# 125 ORAL SURGERY / PERIODONTICS

# 126 RESTORATIVE / PERIODONTICS                                    

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Oral Surgery - Perio

1. third molar extractions
2. periodontal status of second molars associated with impacted third molars
3. periodontal concerns with interdental osteotomies after orthognathic surgery

Restorative Dentistry- Perio

1. general restorative considerations for periodontal health
2. the effect of amalgam overhangs on perio status
3. periodontal condition of abutments in fixed bridges
4. normal dimensions for the dentogingival junction
5. the crown lengthening procedure
6. presence or absence of interdental papilla in humans
7. esthetic crown-lengthening procedures
8. response of the human periodontium to crown preparations
9. the affect of removable partial dentures on the periodontium
10. concepts and indications for splinting teeth
11. tooth-retained overdentures

# 125 ORAL SURGERY / PERIODONTICS

1. Should the recommendation for third molar removal be made to every patient? Are these teeth more susceptible to periodontal breakdown? What affect does third molar removal have on the periodontium of adjacent teeth?

1. Osborne WH, Snyder AJ, Tempel TR. Attachment levels and crevicular depths at the distal of mandibular second molars following removal of adjacent third molars. J Periodontol. 53:93-95, 1982.

2. Kugelberg CF, et al. Periodontal healing two and four years after impacted lower third molar surgery. A comparative retrospective study. Int J Oral Surg 1990; 19: 341-345

3. Giglio J, Gunsolley J, Laskin D, Short K. Effect of removing impacted third molars on plaque and gingival indices. J Oral Maxillofac Surg 1994; 52: 584-587

4. Kan KW, Liu JKS, et al. Residual periodontal defects distal to the mandibular second molar 6-36 months after impacted third molar extraction. J Clin Periodontol 29:1004-1011, 2002.

2. If patients are having maxillofacial surgery, are there any particular concerns with the periodontium about which they should be advised? Do osteotomy cuts damage the periodontium?

1. Schultes G, Gaggl A, Karcher H. Periodontal disease associated with interdental osteotomies after orthognathic surgery. J Oral Maxillofac Surg 56:414-417,1998.

2. Foushee D, et al. Effects of mandibular orthognathic treatment on mucogingival tissues. J. Periodontol. 56:727- , 1985.

# 126  Restorative Dentistry / Periodontics

Non-Implant Supported Fixed and Removable Prosthesis

1. Discuss periodontist/restorative dentist interactions, especially with regard to treatment planning and maintenance. What factors are important to consider for long term success? Does the position, material or span of replaced dentition change any of these factors? What common complications are seen with fixed restorations?

1. Maynard J., Wilson, R: Physiologic dimensions of the periodontium significant to the restorative dentist. J Periodontol 50:170, 1979

2. Gracis, S et al: Biological integration of aesthetic restorations: Factors influencing appearance and long –term success. Periodontol 2000 27:29-44, 2001

3. Kois, J: The restorative-periodontal interface: Biological parameters. Periodontol 2000 11:29-38, 1996

4. Nyman S, Lindhe J. A longitudinal study of combined periodontal and prosthetic treatment of patients with advanced periodontal disease. J. Periodontol. 50:163-169, 1979.

5. Goodacre C. et al. Clinical complications in fixed prosthodontics. J Prosthet Dent. 2003 Jul;90(1):31-41

2. What are some considerations for the margin placement and morphology of dental restorations? How can this affect the periodontium? Can dental treatment of the coronal aspect of a tooth cause changes in the clinical attachment? In the microbial population? How does the periodontal condition of a tooth affect the restorative plan?

1. Jeffcoat MK, Howell TH : Alveolar bone destruction due to overhanging amalgam in periodontal disease. J. Periodontol. 51:599-602, 1980.

2. Lang N, Keil R, Anderhalden K : Clinical and microbiological effects of subgingival restorations with overhanging or clinically perfect margins. J. Clin. Periodontol. 10:563-578,1983.

3. Pack ARC, Croxhead LJ, McDonald BW : The prevalence of overhanging margins in posterior amalgam restorations and periodontal consequences. J. Clin Periodontol.17:145-152, 1990.

4. Rodriguez-Ferrer HJ, Strahn JD, Newman HN. Effect on gingival health of removing overhanging margins of interproximal subgingival amalgam restorations. J Clin Perio 7:457-462, 1980.

5. Wang, H et al: The relationship between restoration and furcation involvement on molar teeth. J Periodontol 64:302-305, 1993

6. Silness J : Periodontal conditions in patients treated with dental bridges. II. The influence of full and partial crowns on plaque accumulation, development of gingivitis and pocket formation. J.Periodontal Res. 5:219-224, 1970.

7. Valderhaug J et al: Oral hygiene, periodontal conditions and carious lesions in patients treated with dental bridges. J Clin Periodontol. 1993 Aug;20(7):482-9.

8. Nyman S, Ericsson I : The capacity of reduced periodontal tissues to support fixed bridgework. J. Clin. Periodontol. 9:409-414, 1982.

9. Lee HE, Wang CH, Chang GL, Chen TY. Stress analysis of four-unit fixed bridges on abutment teeth with reduced periodontal support. J Oral Rehab 1995; 22:705-710. 

3. Describe the crown lengthening procedure. What anatomic considerations must be taken into account? How constant is the biologic width? Is it the same for all patients? How do we determine whether or not bone or soft tissue needs to be removed? What flap design would be needed for clinical crown lengthening?

1. Gargiulo A, Wentz F & Orban B: Dimensions and relations of the dentogingival junction in humans. J. Periodontol. 32:261-267, 1961.

2. Barboza E et al. Supracrestal Gingival Tissue Measurement in Healthy Human Periodontium. Int J Periodontics Restorative Dent 2008,28:55-61.

3. Perez J et al: Clinical Evaluation of the supraosseous gingivae before and after crown lengthening. J Periodontol 2007:78:1023-1030

4. Herrero F, Scott J, Maropois P, Yukna R A. Clinical comparison of desired versus actual amount of surgical crown lengthening. J Periodontol 1995:66:568-571.

5. Bragger, et al: Surgical lengthening of the clinical crown. J Clin Periodontol 19:58-63, 1992

6. Pontoriero R et al: Surgical crown lengthening: A 12-month clinical wound healing study. J Periodontol 72:841-8, 2001

7. Deas D., et al: Osseous surgery for crown lengthening: A six month clinical study. J Periodontol, 2004 Sep. 75(9):1288-94

8. Tarnow DP, Magner AW, Fletcher P. The effect of the distance from the contact point to the crest of the bone on the presence or absence of the interproximal dental papilla. J Periodontol 1992; 12: 995-996

4. How does esthetic crown lengthening differ from functional crown lengthening? What treatment parameters must be considered prior to surgery? What information about the final restoration is needed to correctly plan? Are there differences if restorations are involved? When is periodontal treatment not enough?

1. Jorgensen M, Sowzari H: Aesthetic crown lengthening. Periodontol 2000 27:45-58, 2001

2. Garber, D., Salama M: The aesthetic smile: Diagnosis and treatment. Periodontol 2000 11-28, 1996

3. Robbins JW: Differential diagnosis and treatment of excess gingival display. Pract Periodont Aesthet Dent. 11(2):265-272, 1999

4. Wise MD : Stability of gingival crest after surgery and before anterior crown placement. J Prosthet Dent 1985; 53: 20-23

5. Carnevale G, di Febo G, Fuzzi M. A retrospective analysis of the perio-prosthetic aspect of teeth re-prepared during periodontal surgery. J Clin Perio 17:313-316,1990.

5. What are the ways in which restorative materials can affect gingival tissue? How would you address changes in oral mucosa that appear soon after a restoration? What if it is a new patient and an older restoration?

1. Dragoo MR, Williams GB : Periodontal tissue reactions to restorative procedures. Part I. Int. J. Perio. Rest. Dent. 1(1):9-24, 1981.

2. Dragoo MR, Williams GB : Periodontal tissue reactions to restorative procedures. Part II Int. J. Perio. Rest. Dent. 2(2):35-46, 1982. 

6. What important considerations must be taken in to account when designing RDPs for patients with periodontally compromised dentition? How does the tissue react on perio healthy patients?

1. Petridis H, Hempton TJ. Periodontal considerations in removable partial denture treatment: a review of the literature. Int J Prosthodont. 2001 Mar-Apr;14(2):164-72.

2. Bissada N, et al. Gingival response to various types of removable partial dentures. J Periodontol. 45:651-659, 1974.

3. Wright PS, Hellyer PH. Gingival recession related to removable partial dentures in older patients. J Prosthet Dent 74:602-607,1995.

4. Hansen C, Clear K, La Mar S. Removable partial denture design considerations where periodontally compromised teeth exist. Int J Periodont Rest Dent 1997; 17: 89-93.

7. What kind of splints exist? How does splinting affect the periodontium? What is the relationship between splinting and mobility? When do we offer splinting as part of restorative treatment?

1. Glickman I, Stein RS, Smulow JB. The effect of increased functional forces upon the periodontium of splinted and non-splinted teeth. J. Periodontol. 32:290 - , 1961.

2. Kegel W, Selipsky H, Phillips C : The effect of splinting on tooth mobility. I. During initial therapy. J. Clin. Periodontol. 6:45- , 1979.

3. Serio FG. Clinical rationale for tooth stabilization and splinting. Dent Clin NA 43:1-6,1999.

8. Are tooth-retained overdentures a valid treatment option? For whom would this be a good option? What complications can be associated with this therapy?

1. Lauciello, F Ciancio, L: Overdenture therapy: A longitudinal report. Int J Perio Rest Dent. 4:63, 1985

125  ORAL SURGERY / PERIODONTICS

1. Should the recommendation for third molar removal be made to every patient? Are these teeth more susceptible to periodontal breakdown? What affect does third molar removal have on the periodontium of adjacent teeth?

Osborne 1982                     ARTICLE
Purpose:  To determine whether definitive root planing and curettage would influence the periodontal attachment and crevicular depth on the distal of second molars, following removal of impacted and partially erupted 3rd molars.
Materials and methods:  18 pts (18-25 years old) with similar bilateral impactions classified as either bony or soft tissue impaction or as partially erupted.  PD measured at distobuccal, mid-distal and distolingual of 2^nd molars. CAL was measured from cusp tips and marginal ridge to base of pocket.  Also assessed GI and PI.  On left side (test side), the distal root of the 2nd molar was planed and the tissue curetted and sutured after extraction of 3^rd molars.  On the right side (control side), neither curettage nor root planing was done following 3d molar extraction.  Measurements, indices, impressions, radiographs and clinical photographs were made pre-op, 3 months and 1 year after 3d molars removal (15/18 returned for 3 month and 1 year follow-up).
Results:  NSSD were seen in PD average (3.8 control vs. 3.4 exp.), attachment level (5.5 control vs. 4.8 exp.), GI or PI.  The results were the same for all the three classes (bony impactions, tissue impactions, and partially erupted) of third molars.
Conclusion: The results of this study support the findings of Ash that root planing of adjacent 2nd molars is of little value in reducing post-op crevice or inducing reattachment.  The best means of preserving periodontal attachment may be the removal of 3rd molars at an early stage of tooth development.

Kugelberg 1990                     ARTICLE                    perio status of second molars
Purpose: To compare the periodontal condition of the adjacent 2^nd molar 2 and 4 years after impacted mandibular 3^rd molar extraction with special emphasis on age.
Materials and methods:

1. 51 subjects (23M, 28F, 17-53 years old) selected at random from the retrospective survey.

2. The patients were examined at 2 and 4 years after impacted mandibular 3^rd molar extractions for PI, GI, PD, and radiographic measurements of proximal bone level (BL) and intrabony (IB) defect depth.

3. The patients were divided into two groups for < 25 years old and > 25 years old.

4. Only PDs greater than 3mm were recorded. PDs were divided into two groups: 6mm, and 7mm.

5. The intrabony defects were measured on PA xrays that were taken with and without a perio probe placed in the deepest part of the defect (standarized). The depth of the defect was measured from the CEJ to the bottom of the defect on the PA film (with the probe in place) with a transparent ruler.

Results: 

1. NSSD in the three clinical variables between 2 and 4 years. 

2. At 4 years, 25% of  < 25 years old group and 52% of > 25 years old group had PD of 7mm or more on the distal of 2^nd molars adjacent to the extraction sites. 

3. NSSD in height of the alveolar crest on the distal surface was observed between 2 and 4 years for either group. 

4. SSD between both groups for the alveolar height at both examinations. 

5. Proximal bone levels showed SS improvement in the younger group.  46% of the young patients showed a decrease in IB defects, and 54% were unchanged. 

6. None of the younger patients had increased in (IB) defects but 30% increased in IB in the older group (15% decreased).

7. Intrabony defects 4mm in subjects < 25 yrs were recorded in 17% of the cases 2 years post-op, while present only in 4% of the cases 4 yrs post-op. The older group were 41% after 2 yrs and 44% after 4 yrs.

8. Mean age for decreased PD was 23.5, unchanged 27.8 and increases in the PD depth the mean was 33 years. 

9. All deteriorated cases were >26 years and 73% of improved cases were <25 years.

BL:  Younger pts have a better resolution of defects after impacted 3^rd molar extractions. Periodontal healing after mandibular 3^rd molar extractions is a continuing process even after 2 years in young pts. When the need for extraction of the impacted 3^rd molar can be foreseen, it may bebeneficial to perform the procedure at a younger age, specifically under 25 years old

Giglio 1994                     NO ARTICLE
P: To investigate the effect of removal of partially erupted mandibular 3^rd molars on the plaque & gingival indices of other teeth.
M&M: 60 pts were assigned to 3 groups. Group 1 (Ctrl) had 3^rd molars congenitally missing or previously removed, group 2 had asymptomatic, partially erupted 3^rd molars, and group 3 was experiencing acute pain associated with a partially erupted 3rd molar. None of the pts were under periodontal maintenance or active perio tx. PII & GI were recorded in all 4 quads before and 6 weeks after surgery. No OHI were given.
R/Disc: Both GI and Pl improved in the symptomatic group while only the Pl improved in the asymptomatic group. Neither of the test groups scored as low as the control group post-op. This could be either due to a possible bias in the ctrl group toward better OH, or to the fact that healing was not yet complete influencing the pts ability to perform proper OH. Data from the 2^nd molar adjacent to the sx site was analyzed separately showing that these alone were not responsible for the mean score improvement.
BL: The removal of impacted teeth may provide some benefit in terms of improved gingival health by reducing the plaque index.
Cr: short follow-up period

Kan 2002                     ARTICLE
P: 1) describe the periodontal conditions and other associated features of mandibular 2^nd molars after surgical extraction of impacted 3^rd molars.
2) identify the characteristics of impaction patterns which were associated with persistent post-extraction periodontal problems of these 2^nd molars.
M&M: List of patients that had undergone extraction within a 30-month period was generated from the hospital’s computerized records, in the University of Hong Kong.
Eruption pattern of the 3^rd molars and patient data (gender, age, time since extraction, smoking habits and history of scaling since the extraction) were recorded.The pre-extraction panoramic radiograph was studied and the impaction pattern of the 3^rd molars and the presence of a crestal radiolucency indicating loss of crestal bone between the mandibular 2^nd and 3^rd molar were recorded.  Community Periodontal Index (CPI) protocol and the specific clinical condition of the subject mand 2^nd molar (PD, Rec, BOP, suppuration on probing (SOP), tooth mobility and furc involvement) were assessed by two calibrated examiners. Plaque control and presence of caries lesion or a restoration at distal surface of the subject tooth were also recorded.
Results: 158 were examined in the study out of the 321 cases sampled initially from the computer list. 39% of patients were men and mean age 27.7 years. 77% had never smoked, 18% were current smokers and 5% former smokers. 67% had history of scaling after extraction, 49% had left 3^rd molars extraction and 65% were partially erupted. 76% were classified as mesio-angular impactions and 18% were found to exhibit crestal radiolucency on the pre-extraction radiograph. The % of subjects having a highest CPI score of 2,3 or 4 were 53%, 41% and 6% respectively. Periodontal conditions of Mand 2^nd molar 6-36 months following surgical extraction of adjacent impacted 3^rd molar (n=156)

(SOP) Suppuration on probing 

Plaque was detectable on the distal surface of 87% of subject teeth, 1% showed furcation involvement, 3% had Grade I mobility and 1% Grade II. 6% had caries on the distal and 4% restoration.
PD was correlated with plaque detection at the distal of the 2^nd molar and presence of crestal radiolucency. No association between PD distal of 2^ndmolar and the length of time since surgical extraction of the 3^rd molars.
Conclusion: Periodontal breakdown initiated and established on the distal surface of a mandibular second molar in the vicinity of a ‘mesio-angular’ impacted third molar evidenced by pre-extraction crestal radiolucency in association with inadequate plaque control after extraction can predispose to a persistent localized periodontal problem.

2. If patients are having maxillofacial surgery, are there any particular concerns with the periodontium about which they should be advised? Do osteotomy cuts damage the periodontium?

Schultes 1998                      ARTICLE
Purpose: To evaluate the periodontal situation near interdental osteotomies after orthognathic surgery.
Materials and methods: 
30 patients with Class II malocclusion were studied 4-10 years after orthognathic surgery and orthodontic treatment.
15 anterior maxillary osteotomies, 10 sagittal maxillary splits, 9 Le Fort I osteotomies and 8 anterior mandibular segmental osteotomies were evaluated.
10 patients received ortho before the surgery and 20 patients had orthognathic surgery only.
Panoramic and periapical radiographs were made of the osteotomy region for every patient and the periodontal status was assessed.
A reduction in bone mass of 1/3 of the root length was classified as marginal superficial periodontitis and a further reduction as profound marginal periodontitis.
Post-op tooth loss was confirmed by comparison with pre-op radiographs. Lateral root resorption at the osteotomy sites was recorded.
Results:
51 pathologic periodontal findings in the 74 segmental osteotomy sites.
Periodontal pockets were found in 35 cases and post-op tooth loss in 16 segmental regions.
Average of 1.1 teeth per patient lost because of segmental osteotomies. In addition, 1.2 teeth per segment showed severe damage to the periodontium.
Superficial periodontal lesions were found in 1.7% and deep periodontal lesions in 47.5% of the osteotomy sites. 22% of the osteotomy sites showed a loss of teeth.
Lateral root resorption was present in 15.3% of the osteotomy sites. In the ortho treated patients 7/10 showed apical root resorption of mandibular and maxillary anterior teeth.
BL: A high incidence of dental and periodontal trauma occurs in the region of segmental osteotomies after orthognathic surgery.

Foushee 1985                       ARTICLE
P: To determine if alterations in mucogingival status (recession, width of KG, width of attached gingiva) occur in mandibular anteriors and premolars in patients after chin repositioning (genioplasty)
M+M: 24 patients (12-34 years old, 18 F 6M) evaluated for Orthognathic therapy; orthodontic treatment was performed and then genioplasty with or without mandibular advancement. Pretreatment measurements only on the facial surfaces of mandibular anteriors and premolars: width of KG, PD, recession, and width of attached gingiva. Second evaluation was done between 3 months and 3 years after surgery. 21 patients analyzed statistically looking at centrals, canines, and premolars. 8 patients received maxillary Osteotomies, 6 patients had mandibular advancement, 10 patients had maxillary and mandibular surgeries. 16 / 24 had either mild or moderate gingival inflammation with no PDs > 4 mm preoperative.
R: After Orthognathic treatment: SS decrease in KG for mandibular anteriors (median change = -0.5 mm) but no change for premolars. SS decrease of attached gingival for all teeth after surgery (median change for canines and premolars = - 0.5 mm, median change for incisors= 0). 10 / 24 showed post-treatment recession (4 pts had 0.5mm or less, while 6 pts had 0.5 to 3 mm). 5/6 pts having significant recession post-treatment had mandibular advancement in addition to genioplasty.
BL: The pretreatment width of keratinized and/or attached tissue was not the critical factor in development of recession. Risk of recession increased when genioplasty was combined with mandibular advancement and occur at sites where KG and underlying bone appeared thin.
Cr: All pretreatment measurements were taken by one examiner, and all posttreatment measurements were taken by a different examiner and then they were calibrated and analyzed for agreement.

126  Restorative Dentistry / Periodontics
Non-Implant Supported Fixed and Removable

 

1. Discuss periodontist/restorative dentist interactions, especially with regard to treatment planning and maintenance. What factors are important to consider for long term success? Does the position, material or span of replaced dentition change any of these factors? What common complications are seen with fixed restorations?

Maynard 1979                     ARTICLE
D: When treating patients, the objectives of restorative therapy must be clear. The first and most basic objective is preservation of the teeth. The attainment of this objective would be far less complex if it could be considered independent of restoration of function, comfort and esthetics, but such is not the case. The latter objectives usually require sophisticated restorative dentistry and often include restorations with intracrevicular margins. Although it is widely accepted that the best restorative margin is one that is placed coronal to marginal tissue, most restorations have margins in the gingival crevice, and permanent tissue damage is common. In attempting to reach his objective, the restorative dentist must remember the fundamental precept of the health professions, which is: Do no harm. Daily observation of the three physiologic dimensions permits the therapist to restore teeth with minimal injury to the periodontium.
 

Gracis 2001                     ARTICLE
P: To discuss factors that determines the esthetic and long term success of esthetic restorations.
D:
Anatomical consideration
Biologic Width: Many authors have highlighted the inevitability of penetrating the epithelial attachment during the prosthetic procedures without causing any irreversible damage. Therefore, nowadays, ‘‘true’’ biological width violation means the placement of a restorative margin in the connective tissue attachment.
Papilla: The height of the interproximal papilla depends not only on the bone architecture but also on the relative tooth proximity: the closer the crowns, the more accentuated the papilla because the soft tissues tend to be supported by the proximal contours of the crowns. When preparing a tooth, the tip of the bur should therefore follow the gingival margin or the anatomic
configuration of the cementoenamel junction.
Thin Biotype: More at risk of recession, place margins supragingival.
Root prominences: Must be recognized for presence of fenestrations or dehiscences,
contraindication to placing margins subgingivally.
Supra vs intracrevicular margins
Supragingival, are easier to temporize, take impressions off, allow assessment of the fit of the restoration, allow margin finishing and burnishing, and facilitate plaque removal. Intracrevicular restorations cause more periodontal problems; this might be due to defective margins, inaccurate fit, roughness of the tooth–restoration interface, improper crown contour, violation of the connective tissue attachment, and greater pathogenicity of the subgingival dental plaque.
Factors that may force the clinician to place a restoration margin intracrevicularly:
- Need to improve the resistance and retention form of a short clinical crown
- Presence of caries or restorations extending apical to the gingival margin
- Modification of the emergence profile
- Aesthetics.
Phase one should be done first, Intrasulcular preparations should be performed exclusively in presence of a healthy crevice: only when it is inflammation free is the gingival margin stable and less prone to recession and can be probed and packed more accurately. Therefore, an intracrevicular margin should be placed 0.2 to 0.5 mm apical to the free gingival
margin on the facial side. Interproximally, because the sulcus normally is deeper, the preparation can extend more apically to better support the soft tissues. Some authors suggest placing a retraction cord in the sulcus before finalizing the preparation.
This maneuver has two advantages: it highlights the base of the sulcus and therefore the ultimate limit of the preparation before causing irreversible damage, and it pushes the gingival margin outward and apically to better expose the unprepared tooth structure to be removed.
The sequence of clinical steps consists of:
- Tooth preparation to the gingival margin
- Placement of an extra-thin knitted retraction cord that displaces the gingiva outward and
apically
- Definitive margin preparation to the top of the cord achieving a new, more apical position.
Provisionals
Protect the prepared teeth, to reduce the sensitivity of the vital abutments, and to prevent tooth migration. They are also instrumental in developing the correct aesthetics, phonetics and occlusal scheme before fabrication of the definitive restoration. More importantly, well-contoured and well-fitting provisional restorations allow the periodontal tissues to stay or become healthy.
Special attention should be dedicated to the development of the proper emergence profile of the provisional prosthesis.
Impression technique
The impression technique can have a negative impact on the soft tissues around the abutments, even causing irreversible damage if the technique is not properly carried out. The objective of tissue retraction is to expose all of the prepared tooth structure and, possibly, a portion of the unprepared root beyond the margin by causing a horizontal and vertical displacement of the marginal gingiva. A single-cord technique is the least traumatic option and is normally employed when the sulcus is shallow and the margin is placed only minimally in the crevice. A double-cord technique is used when the sulcus is deeper. Root proximity may create severe problems in obtaining good impressions because there will not be enough space to accommodate the retraction cords and, subsequently, a proper thickness of impression material. The placement of cords in such restricted interproximal spaces
may cause irreversible damage. Possible solutions to this problem are: partial- instead of full-coverage restorations to
1.Avoid preparing and restoring the side of the tooth with the proximity problem
2.More apical placement of the restorative margin if the root trunk tapers apically or an
odontoplasty with a flame-shaped bur to increase the separation
3.Orthodontic movement to separate the teeth
4.Strategic extractions.
Choice of restoration depends on:
1.Tissue type,
2.Tooth vitality
3.Abutment integrity
4.Abutment height
5.Occlusal clearance for proper strength
6.Aesthetic needs of the patient
7.Parafunctional habits
   
Posts
Fiber posts are more esthetic, however, may flex which has been associated with loss of the cement lute marginal seal and microleakage. Metal posts are rigid but can negatively affect esthetics.
 

Preparation design
Preparation designs for full-coverage restorations may be classified into four distinct types:
- Feather-edge: Frequently used for gold crowns and porcelain and composite veneers, lack resistance, and can cause over contouring, use should be limited.
- Chamfer: Widely used because of ease of preparation, however, according to some authors, the thin metal collar may distort during the firing of porcelain, thus producing inaccurate margins. The visibility of the metal does not allow these crowns to be used in areas where the aesthetic demands are high
- Shoulder with bevel: It is more conservative than a full shoulder preparation, but the presence of the metal collar necessitates an intracrevicular preparation in aesthetic areas
- Shoulder: The shoulder is probably the most popular design because it is very easily read by the technician, and it allows sufficient bulk for porcelain to produce aesthetically pleasing restorations
 

 

Kois 1996                     ARTICLE
Purpose: To examine several biological parameters looking at the restorative-periodontal interface
Discussion: 

• Bacterial plaque accumulation: Plaque retention depends on surface roughness and the surface energy of the restorative material. The short-term positive gingival response of provisional restorations may not be a good indicator of the long-term gingival health. Mechanical insults such as bands, cord and retraction clamps can disrupt JE and CTA. This might heal with a recession that will self correct in the future. Possibly prescribe CHX for 2-week regimen with OHI if indicated

• Marginal integrity of restoration: Clinical parameters of what constitutes acceptable margin have never been established. Marginal wear or ill-fitting prosthesis might lead to gingival inflammation but not progression of perio dz. 62% of restorations have an opening of at least 200 μm, bacteria generally range from 1-5 μm. 

• Coronal contour must mimic natural teeth. It’s unclear what the definition of over- and undercontoured actually is. As contour is increased in 0.5 mm increments to 1.5 mm greater than original tooth dimension, papillary bleeding increases. This can be a problem for both supra- and subgingival margins. Close root proximity increases the importance of interproximal contour. Slight deviations can compromise the gingival tissue. One should be able to pass an explorer through to sulcus. If not, overcontoured. 

• Alloy sensitivity: Ni containing alloys greatest risk of hypersensitivity. Contact dermatitis is most common mode of adverse reaction.

• Margin location: Subgingival margins tend to be worse for gingival health. Most critical factor appears to be relationship to supracrestal fiber attachment. If margin placed in biologic width, adverse long term health seen. Need to locate the base of the gingival sulcus; however, in varying degrees of inflammation, probe penetrates differently. The osseous scallop is greatest in the anterior and flattens as move to posterior. If do not follow this scallop, may violate the biologic width in one area and not another on the tooth. If the biologic width is violated, might have recession. This depends on biotype and tissue management. 

BL: The proper margin location of restoration relative to the alveolar bone is one of the critical parameter to ensure long-term gingival health
 

Nyman 1979                     ARTICLE
Purpose: To present the results of periodontal and prosthetic treatment of patients with advanced breakdown of the periodontal tissues.
Materials and methods: 299 individuals were divided in two groups. Group I:non-bridge treatment group (48 patients). A well-functioning dentition could be established with periodontal treatment only. Group II (251 patients): bridge treatment group. Prosthetic treatment was required subsequent to the treatment of periodontal tissues. Following the active phase of treatment, all patients were placed in a maintenance program which included recalls every 3 to 6 months. Patients of Group I have been followed up for 8 years and those of Group II for 5 to 8 years. Following initial treatment and then once a year, the following parameters were assessed: PI, GI, PD, AL, and marginal alveolar bone height. Also, the frequency of and the reasons for technical failures in the bridgework were assessed. 332 fixed bridges were analyzed.
Results: Final examination (8 year follow-up for Group I and 5 to 8 years for Group II) revealed that both groups maintained low plaque scores and gingival indices. In none of the treatment groups, PDs varied in a significant way during the course of the study. Bone level was maintained unchanged in both groups. The analysis of the 332 bridges regarding frequency and reasons for bridge failures revealed:  1) Loss of retention of retainer crowns from abutment teeth (11 bridges, 3.3%), 2) Fracture of bridge (7 bridges, 2.1%), 3) Fracture of abutment tooth (one tooth in 8 bridges, 2.4%).
Conclusion: Following periodontal treatment, periodontal health can be maintained in patients enrolled in a controlled OH program. Supportive periodontal therapy (SPT) in this study was equally effective for patients with bridge work. Severe reduction of periodontal support around abutments and differences in bridgework design did not influence the periodontal status. However, technical failures occurred in 26 out of 332 bridges. These failures appeared as loss of retention, fracture of bridgework, and fracture of abutments.
 

Goodacre 2003                     ARTICLE
Purpose: To identify the incidence of complications and the most common complications associated with single crowns, FPDs, all-ceramic crowns, resin-bonded prostheses, and posts and cores.
Materials and methods:
Medline and extensive hand search covered the last 50 years and focused on publications that contained clinical data regarding success, failure, and complications.
Results:
Most common single crown complications
 

 
Most common fixed partial denture complications
 

     
Most common all -ceramic crown complications
 
 

   
 
Most common resin-bonded prosthesis complications
 

 
Most common post and core complications
 

2. What are some considerations for the margin placement and morphology of dental restorations? How can this affect the periodontium? Can dental treatment of the coronal aspect of a tooth cause changes in the clinical attachment? In the microbial population? How does the periodontal condition of a tooth affect the restorative plan?

Jeffcoat 1980                     ARTICLE                            amalgam overhangs
P: Examine the effects of overhanging amalgams on the alveolar bone height in patients with periodontal disease.
M&M: Examined records of 4600 patients screened for Overhangs. 100 selected with contralateral controls (no overhangs). Overhangs classified as small (occupies< 20% interproximal space), medium (20-50%), large (> 50%). Patients classified as to perio Class I-IV (ADA). Bone loss compared to control measured from CEJ to crest divided by root length using
radiographs.

R:  71% greater bone loss on overhang side vs. control. Small overhangs did not result in SSD vs. control but larger overhangs result in more bone loss. For each periodontal disease type the bone loss around the experimental teeth exceeded the control (5.6% for class I, 6.7% for class II, 12% for class III).
BL: Bone loss from overhanging amalgams is due to plaque retention and inflammation due to impingement of the embrasure space
 

Lang  1983                     ARTICLE
P: To determine if placement of subgingival restorations with overhanging margins results in change in the subgingival microflora.
M&M: 9 dental students with gingival index scores < 0.1 (pts had SRP and OHI first) requiring 10 gold MOD onlays for caries control. All MOD onlays preps were made with margin 1.0 mm subG;. Each tooth had 2 restorations fabricated: one with clinically perfect margins and one with 1.0 mm proximal overhangs. In a cross-over study, half of the teeth (5) had onlays w/1 mm proximal overhangs for 19-27 weeks that  were then replaced by 5 onlays with perfect margins. Another 5 teeth had onlays with perfect margins placed first (8-24 wks) which were then replaced with the 1 mm overhang MOD onlays (12-27 wks). Patient cleaned normally, except NO IPx cleaning at the site of the onlays. Prior to and every 2-3 weeks after insertion, PI, GI, subG microbiological samples (paper point) and PD to the level of the proximal margin of gold onlay were recorded..
R/D: Without overhangs, no increase in BOP at sites (if overhangs placed first, by the end of 2^nd experimental period BOP had resolved). With overhangs, both groups by end of experimental period were at 100% BOP and GI of 2 or 3. For PD, as GI increased, so did the measurement to the FGM. There was no change from margin to base of sulcus (pseudopocketing with inflammation). With overhangs; there no change in the amount of plaque found subG, but rather the subgingival flora began to resemble chronic perio, w/ increased Gram - anaerobic bacteria, black pigmented Bacteroides (1.6%-3.8%) and increased anaerobe facultative ratio. With clinically perfect margins a microflora characteristic of health or initial Gingivitis was observed. Pts individually had different time frames for developing this flora, indicating host resistance/susceptibility.
BL: Placement of restorations with overhanging subgingival margins result in a change of subgingival microflora to one that may be associated with periodontitis, which documents a potential mechanism for iatrogenic initiation of periodontal disease. Host susceptibility plays a role in the time frame of how long it took to shift to a more peridontopathic microflora
 

Pack 1990                     ARTICLE
P: To determine prevalence of overhanging margins and associated periodontal status in 100 patients with completed treatment by final year dental students.
M&M: 100 subjects. PD, BOP, and clinically detectable margins recorded on all posterior teeth, and BWs were taken. No attempt to determine size of overhangs.
R: 1319 teeth with 2117 restored surfaces were examined.
- Prevalence: 1186 restored surfaces (56%) had overhangs, 62% of all restored interproximal surfaces
- 62% of distal, 60% mesial, 35% buccal, and 40% of lingual restorations had overhanging margins
- 69% of distal, 54% of mesial restorations next to the edentulous space had overhanging margins
- PDs > 3 mm: 64.3% of overhangs, 23.1% for unrestored surfaces, and 49.2% for non- overhanging restorations
- BOP, 32% of pockets adjacent to overhangs bled on probing, 10.5% for un-restored and 21.6% for non-overhangs.
BL: Periodontal disease was more prone in the presence of poor margins. These overhangs significantly affected the periodontal status of the teeth.
 

Rodriguez-Ferrer 1980                     ARTICLE
Purpose: To resolve the influence of removal of subgingival overhanging margins on the healing of gingival tissues and to determine whether it should be carried out at the beginning or at the end of the initial phase of periodontal treatment.
M&M: 15 pts with early to advanced periodontitis and 52 proximal surfaces that had confirmed overhanging restorations (amalgam) after removal of subgingival calculus were selected. Test group: 26 overhangs were removed at the first visit (no palpable transition between tooth surface and restoration). Control group: 26 contralateral-paired overhangs were left untreated. Every surface was scored for GI, PI, and PD at 0, 4, 8, 12 wks. Pts received OHI and performed Bass technique, flossing, toothpick and a proxy brush.
Results: After initial exam, NSD was observed in any parameters between test and control groups. By 12 weeks there was a SD for all indices except PD comparing test and control. The greatest change in gingival responses was seen in the first four weeks. Many of the restorations became supragingival as the marginal tissues responded to therapy.
BL: Gingival inflammation is a constant finding in areas related to Class II subgingival amalgam restorations with overhanging margins. Gingival inflammation is due to plaque accumulation in relation to overhangs, which impedes OH. Overhangs should be removed as soon as possible during initial phase of periodontal treatment.
 

Wang 1993                     ARTICLE
P: Cross sectional study The primary aim was to determine the relationship of crowns, proximal restorations and furcation involvement, and Secondarily was to evaluate the influence of the tooth mobility and endo treatment.
M&M: 134 perio maintenance pt (62 M and 72 F) that had restored and non-restored teeth with or w/o furcation involvement on molar teeth. Most of the restoration margins were supragingival and placed about 5 years prior to the study. 1st and 2^nd molar were examined for the absence of presence of crown type restorations, restorations involving proximal surface, endo tx, furcation involvement, mobility, AL.
Results: 373 of 771 Molars had furcation involvement and 362 had restorations or crowns. 113 were mobile and 37 had RCT. So, molars with crown or restoration had higher prevalence of furc involvement (P<0.01).
 Loss of attachment associated with restorations was marginal(p=0.051), with more loss shown in the maxilla. The diff in AL b/w restored and non-restored molars occurs mostly in the maxillary arch
BL: pts w/ crowns or interproximal restorations are more likely to have furcation involvement and more CAL loss even undergoing regular maintenance.
-self critique: causality cannot be shown by X-sectional studies
 

Silness 1970                     ARTICLE
P: To compare the periodontal condition of abutments and contralateral teeth in patients with
full and partial crowns used for retaining dental bridges.
M&M: 261 individuals, 242 abutment teeth were compared with 242 contralateral teeth in the same patients. Patients were divided into groups depending on receiving periodontal treatment and OHI or not, location of crown margins (sub-g and no sub-g) and type of crowns (full or partial). Instructed group (159 individuals): this group had received periodontal treatment, OHI instructions and reinforcement 2-6 years before the examination. Non-instructed group (102 individuals): this group had received no periodontal treatment and no OHI. So 4 groups were formed: 1) GROUP I: non-instructed patients, full crowns with sub-g margins, 2) GROUP II: instructed patients, full crowns with sub-g margins, 3) GROUP III: instructed patients, full crowns with no sub-g margins, 4) GROUP IV: instructed patients, partial crowns with no sub-g margins. GI, PI, PD and margin index (position of margin in relation to crest) were recorded.
R: Abutments with complete crowns with full coverage and sub-g margin showed larger
amount of deposits, more severe gingivitis and increased PD compared to contralateral teeth
whether or not patients were instructed on oral hygiene. In instructed patients, the periodontal
condition of abutments with complete or partial crowns with limited coverage and no sub-g margin did not differ significantly from those of control teeth.
BL: Abutment teeth with crowns with subgingival margins are associated with more severe
gingivitis, deeper PD, and increased accumulation of plaque, compared to the uncrowned
contralateral teeth even in patients who were instructed in oral hygiene methods.
 

Valderhaug 1993                     ARTICLE
P: The aim of the present study was to assess the level of oral hygiene, periodontal conditions, changes of alveolar bone level and prevalence of caries in a group of patients who had received regular oral prophylaxis following the insertion of fixed partial dentures. Differences of these indices when the crown margins initially were located sub-gingivally, at the gingiva or supragingivally were also recorded.
M&M: 102 patients received a total of 108 cast gold or gold/acrylic bond bridges on 343 abutment teeth. The rest of the teeth on the same jaw that received the restorations served as controls. Clinical and radiographic exams were done at baseline, 5, 10, 15 yrs. PI, GI, PD, were measured. Margins placed >1m below the gingival margins were considered sub-gingival. Bone loss was measured to the nearest 0.5mm. Maintenance was offered every 6 months for the first 10 years. Statistical analysis was done.
R: Data at 5 (88 pts), 10 (71 pts) and 15 years (55 pts) recorded. 16 pts had a new bridge made or extraction of an abutment tooth over time (15.7%). There was NSSD for PI between test and control. Pi increased for 21% to 27% during the 15 year observation period. GI 2 and 3 was more frequent on abutment teeth than control, and more frequent on crowns with sub-gingival margins. A slight increase in PD was observed at 5- years at the teeth with sub-gingival margins. At baseline, 79% of surfaces had PD <2mm, 4% had PD >4mm. At 15 years, 57% of sites were <2 mm, while 3% were >4mm. Buccal surfaces had always shallower PDs than the other 3 surfaces. Sub-gingival crown margins decreased from 64% at baseline to 36% at 15 yrs (more pronounced on buccal). Caries were recorded at 3.3% of the abutment teeth at 5th year, 10% at 10^th year, and 12% at 15th year. NSSD in bone loss could be detected between the test and control teeth or between the different crown margins locations.
BL: patients who were seen for regular OH maintained healthy periodontal conditions and relatively low caries. Many subgingival margins were seen at the gingiva or supragingivally after 10 or 15 yr.

 

Nyman 1982                     ARTICLE
Purpose: To compare the calculated size of the PDL around abutment teeth with the size of the anticipated normal PDL area of teeth replaced by the pontics in bridgework in patients treated for advanced periodontal disease.
Materials and methods: 60 bridges, fabricated 8-11 years before study, chosen randomly out of 332 placed from patients on maintenance. Height of alveolar bone around each abutment assessed in radiographs immediately after completion of active treatment & expressed as a % according to Bjorn. The area of the remaining periodontal membrane of each abutment tooth (in square mm) was calculated form the figure given for the total root
surface area of the particular tooth by Jepsen, 1963. Normal PDL area was calculated for the replaced pontics. Total PDL area of abutment teeth was expressed as a % of the PDL area of the teeth replaced by the pontics.
Results: In 12 bridges (20%) PDL area of abutment teeth was < 25% of PDL area of pontics. 22 bridges (36%) showed PDL of abutment teeth to be 2549% of PDL of pontic teeth, 13 bridges (21%) were 5074% of PDL of pontic teeth, & 8 were 7599% of PDL of pontic teeth. Only 5 bridges (8%) PDL area of abutment teeth were ≥ than PDL of pontics. No bone changes were seen over entire study period.
Discussion: Maintaining a previously periodontally treated dentition free from subG plaque deposits coupled with proper occlusal design of bridgework allows teeth with less than adequate support for bridgework to be used successfully as abutments.
Conclusion: In the presence of good OH and proper bridgework design, the total area of PDL does not have to exceed that of the teeth being replaced. Limitations in cases w/few abutment teeth & reduced support are related to biomechanical problems in bridge work, rather than capacity of periodontium to support bridges successfully.
 

Lee 1995                     NO ARTICLE
Purpose: To analyze the stress induced in the periodontium for a 4- unit bridge with perio breakdown being present.
Materials and methods:
Photoelastic models were made with individual simulated materials for tooth structure & alveolar bone. 3 models fabricated with permanent 2nd premolar & 1st molar missing; 1^st premolar & 2nd molar served as abutment teeth.
Model A represented normal bony support, B represented mod perio disease with loss of 1/3 of alveolar bony support lost, & C severe perio disease with 2/3 of alveolar bony support lost.
The level of alveolar bone of the 1^st premolar of all three models was reduced by cutting of 1/3 to simulate bone destruction and thus nine alveolar bony support conditions were tested. A 4-unit gold fixed denture was fabricated for each model. All models were loaded (200N) in the central holding fossa of each pontic & each retainer of the prosthesis. The stress points were located 5mm directly below the root apices of the abutment teeth.
Results:
Following increase of the alveolar bone resorption on the 2nd molar, the stress concentration indices of both the 1st premolar & 2nd molar increased significantly when loading was applied. When bone resorption of 1st premolar was increased, only the stress concentration index of 1^st premolar increased, but not that of the 2nd molar.
BL: Results indicate the effects produced by the stronger & double-rooted 2nd molar were more prominent & determinant than those of the smaller & single rooted 1st premolar.

3. Describe the crown lengthening procedure. What anatomic considerations must be taken into account? How constant is the biologic width? Is it the same for all patients? How do we determine whether or not bone or soft tissue needs to be removed? What flap design would be needed for clinical crown lengthening?

Garguilo 1961                     ARTICLE
P: To establish a norm for the dentogingival junction in all phases and chronologic ages,
M&M: 30 human autopsy specimens (range age 19-50 years old) were examined for the DGJ (287 teeth with a healthy periodontium). There were 6 different sites measured for each tooth. A total of 325 surfaces were measured. The DGJ consists of sulcus, Epithelial Attachment, and connective tissue (CT) Attachment. The areas measured were:
a) Depth of the gingival sulcus
b) Length of the attached epithelium
c) Most apical point of the epithelial attachment from the CEJ
d) Distance from the sulcus to the CEJ
e) Distance of the CEJ from the alveolar bone
f) Distance from the most apical point of the epithelial attachment to the alveolar bone (CT)
R: Passive eruption can be divided from its 4 phases into 2 divisions: A (phase I and II) and B (phase III and IV). The reasoning is due to the fact that the JE is significantly greater in phase I and II than it is in phase III and IV.
Length of CT attachment is very constant: 1.07mm
Length of epithelial attachment varies more: 0.97mm
Sulcus depth: 0.69mm
Different areas of the same tooth may present different measurements for these parameters.
 

Barboza 2008                     ARTICLE
P: To measure and compare contralaterally the dimensions of SGT in healthy human periodontium.
M and M: This randomized, blinded study on 100 dental students (400 teeth [first molars and second premolars] and 1,600 sites). The dimensions of supracrestal gingival tissue (SGT) were compared contralaterally. Sulcular probing reaching the crestal bone was performed in 100 dental students (400 teeth [first molars and second premolars] and 1,600 sites).
R: Contralateral measurements were statistically analyzed by one-way analysis of variance. SGT measurements ranged from 1.0 to 6.0 mm. Contralateral measurements showed no statistical difference (P = .096). The highest % of identical measurements at contralateral teeth was observed in men on maxillary premolar at the center buccal site. The mean % of identical meaurements was 71.8% the conventional 3mm measurement was found in 46.8% of the sites.
BL:
1. Measurement of SGT contralaterally prior to crown lengthening or restorative procedures may dictate the needed amount of bone removal or tooth preparation into the sulcus.
2. The standard 3mm of bone removal from lengthening or 0.5mm for tooth preparation in the sulcus should be reviewed.
 

Perez 2007                     ARTICLE
P: To determine whether transsulcular probing (TSP) accurately and reproducibly defines the supraosseous gingiva (SOG) dimension compared to direct measurement at surgery; to compare the SOG dimension 6 months after CL to that observed preoperatively; and to determine whether the preoperative SOG for a particular tooth can be used to predict the post crown lengthening dimension.
M: 19 patients (12F and 7M) underwent CL surgery with the surgical tooth acting both as the control and the test site. Pts had to have adequate plaque control, absence of overt signs of gingival inflammation, no clinically significant systemic diseases, at least 18y old, non smokers. The SOG was measured by TSP before and 6 months postop. Stents were used as fixed reference points. The amount of CL required was verified by estimating the position of the new finish line of the restoration after caries removal or by the extent of tooth fracture. Internal bevel incisions were made on the buccal and lingual areas, preserving as much KG as possible and mucoperiosteal flaps were reflected up to the MGJ. Osseous resection was performed using high-speed drilling with diamond burs. APF was sutured using 4-0 silk. Post-op instructions given. Intraclass correlations (ICC) were calculated to test for the reliability of TSP measurements versus direct bone-level (DBL) measurements. A Wilcoxon signed-rank test was used to compare the mean difference between baseline and 6 months postop for the mean buccal, mean lingual, and overall mean SOG.
R: ICC coefficients for TSP measures of SOG to DBL measures of SOG ranged from 83.4% to 91.9%, indicating a high degree of agreement between TSP and DBL. The differences in SOG dimensions, 6 months after surgery compared to baseline, were mean buccal 0.51 mm; mean lingual/palatal, 0.61 mm; overall mean, 0.56 mm (SSD).
BL: TSP is an accurate alternative method to DBL in clinically determining SOG. , with these mean differences being statistically significant.
 

Herrero 1995                     ARTICLE                              crown lengthening procedure 
P: To compare the actual amount of supracrestal tooth length obtained during surgical crown lengthening with the pre-surgical desired amount. The clinical effectiveness of varying degrees of experience was also evaluated.
M&M: 16 pts with 21 teeth requiring crown lengthening for restoration placement participated. The goal was 3.0 mm below the planned margin. 4 faculty, 4 first-year residents, and 4 second-year residents were blinded to the nature of the study and exercised their own clinical discretion as to their having achieved biologic width. At each clinician's discretion, surgical techniques consisted of either GV or APF w/ and w/o osseous resection. A notch was made at FGM (1/2 round bur) and at the proposed new margin. Utilizing a reference stent, measurements were obtained at the F, MF, L, DL of the treated teeth both before and after osseous reduction. Parameters evaluated were gingival margin position, PD, MGJ position, alveolar crest location (during surgery), mobility, PI, and GI. These measurements were again recorded 8 weeks after surgery with the exception of alveolar crest.
R: The default objective of 3 mm between planned restoration margin and alveolar crest was not routinely achieved (mean 2.4 mm). The mean amount of bone resected at the 4 points around the tooth was 0.63 mm. The post-treatment distance from the planned restoration margin to the alveolar crest was greatest at the facial aspect of the teeth (mean 2.6 +/- 1.2 mm) and least at the distal-lingual (mean 2.2 +/- 1.7 mm). In addition, although more experienced periodontists removed a larger amount of bone, the amount of root surface exposed was still short of the initially desired biologic width. (1^st year residents removed 0.00 mm on avg).
BL: The biologic width was not routinely achieved in this study. Most likely to underprepare the DL aspect. Experience increases the amt of bone removed, but total biologic width is still short of desired (3.0 mm) goal.
 

Bragger 1992                     ARTICLE
P: To assess the changes in the periodontal tissue levels as an immediate result of the surgical crown lengthening procedure over a 6-months healing period.
M&M: 25 patients ranging between 20 to 81 years of age were included in the study. A total of
85 teeth (43 test and 42 control teeth not exposed to surgery) were evaluated over 6 months. After initial therapy, the indication for crown lengthening comprised need for increased retention and accessibility to deep subgingival preparation margins hampering impression taking. During surgery, the alveolar crest was reduced 3 mm to the future reconstruction margin. The measurements were standardized using stent.
R: PlI, GI, and PD were not statistically different.
- Immediately after surgery – 6 wks: 33% of test sites had recession (1-4 mm)
- 6 wks – 6 months: 29% of test sites and 23% of control sites had recession
BL: Creating a distance of 3 mm from the alveolar crestal bone level to the future reconstruction margin during surgical lengthening of the clinical crown leads to stable periodontal tissue levels over a period of 6 months
 

Pontoriero & Carnevale 2001                     ARTICLE
Purpose: To assess the alterations of the periodontal tissues immediately after crown lengthening and over a 12-month healing period. 


Materials&Methods: 30 patients (84 teeth) were selected with various conditions hampering proper restorative measures in one or more teeth that would require crown lengthening. Indications included: insufficient retention of prep, access to deep subgingival lesions of preexisting faulty prep margins, and correction of anterior gingival tissue for esthetic reasons. Pt had appropriate cleaning with baseline exam: PD, CAL, PI, GI and gingival margin position. After baseline exam, the patients underwent APF surgery with osseous and CT attachment resection. During surgery, the amount of resection and the achieved lengthening of the clinical crown were evaluated. Periosteal sutures were placed to expose the interproximal bony crest. Maintenance program every 2-4 weeks. The patients were reexamined at 1, 3, 6, 9, and 12 months postoperatively.
Results:

Over a period of 12 months, healing resulted in a SSD coronal displacement of the gingival margin of 3.2 mm at IPx and 2.9 mm at B/L sites. As a consequence of this postsurgical soft tissue regrowth, the amount of the available clinical crown after surgery decreased by 0.5 mm at IPx sites and 1.2 mm at B/L sites at the 12-month examination. Once the data was analyzed, they found a sig relationship b/w the amount of bone reduced at the pattern of tissue regrowth. PD at 12 months was within 0.1 mm of baseline.
Discussion: Regardless of surgical positioning, tend to have tissue rebound after 1 year. This pattern of coronal displacement of the gingival margin was more pronounced in patients with "thick" tissue biotype and also appeared to be influenced by individual variations in the healing response not related to age or gender.
 

Deas 2004                     ARTICLE
P: To assess the short-term stability of surgical crown lengthening procedures using an osseous
resective technique.
M&M: 25 treated periodontally healthy patients requiring crown lengthening of 43 teeth participated in the study. Each patient received initial exam, OHI, scaling and/or prophylaxis was scheduled if deemed necessary by the examining periodontist. Alginate impressions were taken and customized probing stents were fabricated and used for clinical measurements. 3 guidelines were given to each surgeon: 1) place the alveolar crest at least 3mm from the anticipated crown margin, 2) leave at least 9mm of clinical crown height coronal to the osseous crest 3)  place the flap margin either at or apical to the anticipated restorative margin following suturing. Surgery: Intrasulcular and/or internally beveled incisions, elevation of FTF, flap thinning, osteoplasty and ostectomy performed, all root surfaces were scaled and root planed, flaps were sutured and pressure was applied for 3 minutes. All sites on teeth targeted for crown lengthening were labeled treated sites (TT), interproximal sites on neighboring teeth were labeled adjacent (AA) if they shared a proximal surface with a treated tooth and non-adjacent (AN) if they were on the opposite site, away from the treated tooth. Baseline clinical indices were recorded at eight sites on each molar and six sites on each premolar (PI, BOP, PD, distance from stent to the gingival margin, relative attachment level from the base of sulcus to the stent). Surgical measurements at the same sites included the distance from stent to the alveolar bone both before and after osseous surgery and the distance of from flap margin to alveolar bone after suturing. Clinical measurements were repeated at 1, 3, and 6 months after surgery.
R: There was no significant difference between the percentage of treated sites with plaque and BOP at any time point. The decrease in PD was statistically significant from baseline to 1, 3, and 6 months for all three groups (TT, AA, AN). Attachment loss was noted for all three groups and was significant for each group compared to baseline. At TT sites, the mean increase in crown length following surgery was 2.27mm. This crown height was reduced to 1.91mm by 1 month, 1.69mm by 3 months and 1.57mm to 6 months. At each time point there was a significant increase in crown height compared to baseline but there was a trend toward reduced crown height over time. The same trend was noticed in adjacent and non-adjacent sites. The mean osseous reduction at treated, adjacent and non-adjacent sites was 1.13mm, 0.78mm and 0.065mm respectively. When tissue rebound following surgery (6 months) was evaluated, it was noted that the closer the flap margin was sutured to alveolar crest, the greater the tissue rebound during the post- surgical period. The rebound ranged from 1.33-1.02mm the flap was sutured 1mm from the alveolar crest, to -0.161.15mm when the flap was sutured 4mm from the alveolar crest.
C: There is a significant marginal soft tissue rebound following crown-lengthening surgery that has not fully stabilized by 6 months. The amount of coronal rebound appears to be related to the position of the flap relative to the alveolar crest at suturing. Clinicians should establish proper crown height during surgery without overreliance on flap placement at the osseous crest to gain necessary crown length.
 

Tarnow 1992                     ARTICLE                        presence or absence of interdental papilla in humans
Purpose: To determine whether the distance between the contact point and the crest of bone correlated with the presence or absence of interdental papilla in humans.
Materials and methods: 288 interproximal sites. 99 anterior, 99 premolars, 90 molars in 30 patients were randomly selected for examination. Pts underwent thorough SRP 2-8 weeks before the measurements to reduce edema and inflammation. Standardized periodontal probe with Williams markings was used. If there was no visible space apical to the contact point the papilla was deemed to be present. At the time of the surgery the probe was inserted vertically at the facial aspect of the contact point until the bone crest was sounded. To verify the sounded measurements, 38 of the 288 sites were remeasured when the flaps were reflected.
Results/BL:
 

 
When the distance was 3, 4, 5mm papilla was present almost 100% of the times. When it was 7, 8, 9 or 10mm the papilla was missing most of the time. At 6mm it was present a little bit more than half of the time. The majority of areas examined were between 5-7mm in distance.  History of periodontal surgery did not show any definitive trend.  

4. How does esthetic crown lengthening differ from functional crown lengthening? What treatment parameters must be considered prior to surgery? What information about the final restoration is needed to correctly plan? Are there differences if restorations are involved? When is periodontal treatment not enough?

Jorgensen & Nowzari 2001                     ARTICLE                        esthetic crown lengthening procedures
Purpose : Discussion chapter on esthetic crown-lengthening procedures.
Collection of Data: Chief-complaint, expectations, medical history and medications.
Clinical examination:
o     Evaluate face proportions (symmetry, height), avg lip length(20-22mm in women, 22-24mm in men)
o     Tooth display in repose (<2mm in men, 3-4mm in women. During a full smile the upper lip should rest at the mid buccal gingiva of the maxillary central incisors, and the lower lip at the incisal edge of the maxillary central incisors.
o     The maxillary anterior teeth should be parallel to the curvature of the lower lip. 
o     After determining extraoral information, assess the intraoral condition. Determine the dimensions of the teeth, and the height/width proportions. Compare the clinical crown (ging margin to incisal edge) and anatomic crown (CEJ to incisal edge) to differentiate between incisal wear or gingival excess/altered passive eruption.
o     Evaluate the width of KG and whether or not there is an underlying cause for gingival enlargement. X-Ray assessment should be done to assess the height of the interproximal bone and the thickness of the alveolar bone. If unable to ascertain, bone sounding.
Diagnosis: Determine the correct diagnosis, and get all necessary consults. It is important to keep in mind that excessive gingival display, often referred to as the ‘‘gummy smile’’ may be the result of several factors, including gingival enlargement, altered or delayed passive eruption, insufficient clinical crown length, vertical maxillary excess and/or a short upper lip
Treatment planning:
o     Complete caries removal and endo treatment should be done first.
o      If full restorations needed place margins supragingivally, in anterior teeth, avoid overhangs, and do not place margins >0.5mm subgingivaly. If crown lengthening is needed (caries, crown fx), extend to all anterior teeth to achieve harmony.
o     Always try to keep the margins of the restoration in harmony with the CEJ and the underlying bone (mesial/distal margins always higher than buccal and lingual).
o     Plan the surgery according to gingival biotype (allow more healing time for thin), and the width and thickness of KG (intrasulcular incisions in limited KG, tissue graft to increase tissue thickness).
o     Always preserve the interdental papilla and allow at least 8 weeks for healing before the second surgery, if needed. In patients with particularly thin buccal alveolar bone and gingiva, it may be prudent to monitor maturation of the healing tissue for a longer period of time, and in patients with relatively thick buccal alveolar bone and gingiva t may be reasonable to place final restorations less than 6 months following periodontal surgery. The degree of tissue maturation must be taken under consideration when planning the restorative treatment. Effective daily plaque control and periodic recall are essential to maintain long-term stability. Multiple cases are shown to highlight different treatment modalities.
BL: Contemporary dental treatment must result in true oral health, incorporating comfort, function and aesthetics. The key to a successful outcome with long- term stability is the establishment of an accurate diagnosis and subsequent development of a comprehensive treatment plan.
 

Garber & Salama 1996                     ARTICLE
P: Discussion article on esthetic smile diagnosis and treatment.
D:
Three Primary Esthetic Components
 
1) Teeth: Color, position, shape
2) Gingival scaffold:
Harmony and continuity of form to FGM
In its broadest sense, this would require that the gingival architecture for the two central incisors mimic one another. For the lateral incisors, these gingival margins should be somewhat more incisally placed and, for the most part, bilaterally symmetrical. The cuspids would have the free gingival margin at the same level of the central incisors and matching one another. Extending distally, the tissues on the premolars would be somewhat coronally positioned.
Periodontal surgery: Additive (soft tissue grafts) or Resective techniques (APF, GV)
Orthodontic treatment: Intrusion or Extrusion
3) Lip framework
Lip line: Amount of gingival exposure from FGM-inferior border of upper lip, high (> 3 mm), medium (1-3 mm), low (doesn’t show)
Gummy Smile
The gummy smile or high lip-line case with an expanse of soft tissue can result from two basic problems: altered passive eruption and/or vertical maxillary excess. The definitive diagnosis of the problem determines the treatment. One of the clinical criteria in determining which of these two factors is responsible for a "gummy smile" relates to the basic shape of the teeth. If the teeth appear to be somewhat short and squat -meaning that the vertical dimension appears to be too short as compared with the horizontal dimension, the gummy smile is probably due to altered passive eruption. If, however, the silhouette form of the tooth appears to be normal and an expanse of tissue is exposed below the inferior border of the upper lip, this is probably due to an overgrowth of the maxilla in a vertical dimension or a vertical maxillary excess. In many situations, the gummy smile may be a combination of these two factors.
 
Altered Passive Eruption
An aberration in normal development where a large portion of the anatomic crown remains covered by the gingiva. Has been classified into two distinct types:
Type I: Short, square-looking teeth, excessive amount of gingiva
   - Type I-A: Sufficient distance from osseous crest to CEJ
   - Type I-B: Osseous crest at the same level of CEJ
Type II: Normal dimension of gingiva
 
Vertical Maxillary Excess (VME)
Results from a skeletal dysplasia, such as a hyperplastic growth of the maxillary skeletal base. Diagnosis based on normal crown height (Table 2). If there is a combination of altered passive eruption and vertical maxillary excess, altered passive eruption should be treated first and then diagnosis will be made according Table 2.
 
      

                         
 

Robbins 1999                     NO ARTICLE
P: To describe a differential diagnosis for excess gingival display as well as recommendations for treatment.
Diagnosis:
Face height: the length of the middle third of the face should equal the length of the lower third.
Maxillary lip length: The upper lip should measure 20-22mm in young adults females and 22-24mm in young adult males. At rest, there should be 3-4mm of incisal display in young females and 1-2mm in males.
Full Smile: If more than 2mm of marginal gingiva is exposed during full smile it is an esthetic compromise.
Crown length: Maxillary central incisory should be 10-11mm 
Short of hyperactive maxillary lip: Normally, the upper lip should move 6-8mm from repose to full smile. A pt with a hyperactive lip may translate 1.5 to 2 times the normal distance. Facial plastic sx procedures are available  
Altered Passive Eruption (APE) : When the gingiva demonstrates a healthy appearance and the reduced crown length of a central incisor cannot be completely explained by incisal edge wear, a presumptive diagnosis of altered passive eruption is made. Passive eruption continues through adolescence until the gingival margin is within 1 to 2 mm of the CEJ. Altered passive eruption (aka delayed passive eruption) is the term utilized when after tooth is fully erupted, apical migration of the gingiva does not take place, resulting in shorter clinical crowns. If the CEJ can be felt with an explorer, the short clinical crown is due to normal variation, wear or a combination. If the CEJ cannot be palpated, it is considered APE. APE more commonly presents with a distance of 3mm from the gingival crest to the alveolar crest (a simple gingivectomy would rebound to its original position). A FTF is elevated and bone between the line angles is removed. The papilla is not reflected and the interproximal bone is not touched. The bone is left 2-2.5mm apical to the CEJ. When the relationship between the bone and gingiva is understood and respected, the gingiva generally heals with minimal coronal or apical movement. It is often necessary to perform minor tissue recontouring once initial healing has occurred 6 weeks post-op.
 
Dentoalveolar Extrusion: This is when one or more maxillary anterior teeth overerupt. This generally occurs in Class 2 malocclusion. The tx indicated is orthodontics, leaving the teeth in the correct position and with occlusal stops. If sx tx is performed as opposed to the orthodontics, the occlusion more be restored to allow for stable occlusal stops. 
Vertical Maxillary Excess: This occurs when the lower face is longer than the midface. As with dentoalveolar extrusion, the lower incisors may also be hidden by the upper lip. The tentative diagnosis is confirmed with cephalometric rx’s. Orthognathic sx is generally required to treat VME. 
Combination: It is not uncommon for pts to present with multiple etiologies. Many pts with VME also have APE. These pts should first have gingival surgery performed to determine the ultimate length of the clinical crowns, and then have the comprehensive orthodontic and orthognathic sx tx plan made.
BL: Appropriate diagnosis and therapy are necessary for optimal outcomes.
 

Wise 1985                     ARTICLE
P: To determine when to make the definitive crowns for a pt who has had sx pocket elimination and who shows the gingival margins during function.
M&M: 15 pts that needed anterior maxillary crowns were included. They received temps at a supra-g level pre-op. Half received internal bevel gingivectomies and the other half apically positioned flaps. Bone recontouring was done on one pt. A  notch was placed in the temp crown as a reference point. The distance from the reference point to the gingival crest was measured with a compass. Measurements were taken at 4, 6, and 8 weeks, as well as every 4 weeks thereafter (total time of 20 weeks).
R: Six weeks after post-op there was a mean coronal movement of 0.23mm. At 8 weeks, there was a mean apical movement of 0.43mm. A gradual apical movement followed and reached a mean of 0.9mm at 20 weeks post-op.
D: The initial coronal movement of the tissue could be due to swelling, which would explain the rapid shrinkage between 6 and 12 weeks. It is possible that after 24 weeks further apical movement of tissues could occur. The best clinical method is to actually make measurements from a temp crown to the gingival crest and only make the crown when the position of the gingival crest has stabilized for at least 1 month.
BL: Definitive crown preps should not be made for at least 20 weeks after sx.
 

Carnevale 1990                     ARTICLE
P: To evaluate whether clinically significant differences  were present in plaque, gingivitis and probing depths at teeth with artificial crown margins located supra-g, sub-g or at the gingival margin when compared to unrestored natural teeth in patients treated for advanced periodontal disease.
M&M: 510 crowned and 510 natural teeth in 109 patients treated for moderate to advanced periodontal disease were examined.  Out of 510 restored teeth, 351 (69%) were molar teeth, 139 premolar teeth (27%), and 20 anterior teeth (4%). Out of 510 natural teeth, 178 were molars (35%), 283 were premolars (55%), and 49 were anterior teeth (14%). Both treated and controlled sites were undergone periodontal surgery (APF with osseous recontouring). Treated teeth were re-prepared for crown restoration during periodontal surgery. The material used for restorations was porcelain fused to gold with gold collars. The position of the prosthetic margin in relation to the gingival margin was evaluated. When the crown was placed sub-g, the depth was measured and recorded with a periodontal probe.  The time that had elapsed between active therapy and clinical re-examination ranged from 1 to 9 years. All patients were maintained in a recall program that was customized for the patient’s needs (once a month, 3 months, 6 months). The following parameters were assessed: PI, GI, PD (6 sites at each tooth were measured and the highest of the 6 values was recorded as the probing depth for the tooth).
R: NSSD were found between the test teeth and the natural non-restored teeth for plaque and gingival index scores. NSSD in plaque score among supra-g, gingival and sub-g prosthetic margins. SSD were found in GI among the 3 different locations of the crown margins, with gingival position being the best and supra-gingival the worst. The PD of the crowned teeth were measured before periodontal therapy and at the time of the re-examination. Initially, 55% of the crowned teeth had PD 4-5mm, 40% had PD >5mm and 5% had PD <3mm. At the re-examination, in 95.5% of the crowned teeth the PD was <3mm.
C:  A gingival or slightly sub-g location of a prosthetic margin is of no harm to the gingival health of patients correctly treated for periodontal disease, with effective plaque control  and enrolled in a personalized maintenance recall program.

5. What are the ways in which restorative materials can affect gingival tissue? How would you address changes in oral mucosa that appear soon after a restoration? What if it is a new patient and an older restoration?

Dragoo 1981- Part I                     ARTICLE
P: To examine the initial response of the human periodontium to crown preparations and related restorative procedures.
M+M: 4 volunteers (12-51 years old), 10 teeth to be extracted for periodontal or orthodontic reasons, received crown preps on the labial surfaces. The teeth included were in stage II and IV of passive eruption (II: anatomic crown is larger than clinical crown; IV: clinical crown larger than anatomical). 5 categories of restorative procedures:  Crown prep without gingival retraction; gingival retraction before crown prep; crown prep followed by gingival retraction; crown prep followed by electrosurgery; crown prep with rotary gingival curettage. Block sections were taken, decalcified sectioned and stained with Hemotoxin and Eosin.
 

 
R: Differences were seen depending on the state of passive eruption the tooth. When a margin was placed subgingival in a stage II passive eruption, the restoration should be replaced once passive eruption has taken place. Histology of cases where retraction cord was not placed prior to crown preparation or placed following the crown prep showed severe damage to the sulcular epithelium, juncitonal epithelium and connective tissue attachment.  Damage to sulcular and junctional epithelium was minimal when gingival retraction preceded crown preparation. Electrosurgery showed extensive damage to JE, CT, but no bone damage, initially; tip was 1.5mm from bone crest. If a subgingival margin restoration is placed in periodontally diseased teeth, it may exacerbate the disease process.
BL: Damage to gingival complex is minimal when gingival retraction precedes tooth reduction. It is not yet known if the effects of tooth preparation, electrosurgery, and/or rotary curettage is reversible, but it is certainly damaging to the periodontium.
 

Dragoo 1982 - Part II                     NO ARTICLE
  P: To examine the wound healing of insults to the periodontium that are created by subgingival margin placement.
M&M: Eight anterior teeth in immediate denture pts were chosen. The following categories of restorative procedures were chosen: gingival retraction preceding crown prep, crown prep followed by gingival retraction, crown prep followed by electrosurgery, and crown prep using rotary gingival curettage. The plastic temporary crowns had the gingival margins placed in two different positions: labial margin adapted to entire length of gingival bevel (long temporary), labial margin terminated at the shoulder and did not cover the gingival bevel (short temp). The shoulder part of the prep was placed at the level of the gingival margin, and the bevel was placed sub-g. All of the teeth were extracted after 1 month (the average period of time for temporization following final cementation.) Histology was performed.
R: All four groups displayed similar healing one week after tooth prep and temporization. However, the temps with the long margin did have a slightly more inflamed gingiva. At 4 weeks post-op, moderate gingival exudate and inflammation existed with both types of temps. After 4 weeks, all cases had reattachment to the tooth structure. JE was attached to dentin and cementum. The CT was firmly adhered in all cases. Therefore, the group with the short temp had epithelial attachment to the gingival bevel which, the temporary crown did not cover. This, in theory, would later make it difficult to take an adequate impression and not trap any tissue under the casting margins of the final crown. In the electrosurgery group, the burn marks on the roots did not appear to adversely affect the epit reattachment.
BL: If temp cement is properly removed, reattachment to the tooth is not adversely affected by a long or short temp crown.
 

6. What important considerations must be taken in to account when designing RDPs for patients with periodontally compromised dentition? How does the tissue react on perio healthy patients?

 
Petridis 2001                     ARTICLE                    removable partial dentures
P: Critical review of the literature on the periodontal considerations in RPD treatment
M&M: Using Medline search, 884 papers were identified. These were narrowed using keywords and empirical/case reports were excluded. In vivo and in vitro studies were included.
R: Oral hygiene appears to be more crucial for the RPD patient than the FPD patient. RPD’s lead to qualitative and quantitative changes in plaque. Periodontal disease should be treated and controlled and pockets should be eliminated before RPD is fabricated. Insertion of RPD should be delayed if GTR is used on an abutment tooth. There is a lack of information on the status of periodontally compromised abutments. Many of the studies failed to agree on ideal RPD design but did agree that they should be as simple as possible. Clinical trials have shown that if basic principles of RPD design are followed, periodontal health with no mobility can be maintained with frequent recalls and good oral hygiene.
B/L: RPDs do not cause adverse periodontal reactions as long as pre-treatment periodontal health is established and maintained after delivery. Frequent hygiene recalls and prosthetic and prosth. maintenance are essential tools for good long term prognosis. More clinical trials are necessary to determine the effects of RPD on periodontally involved abutment teeth.

 

Bissada 1974                     ARTICLE
Purpose: To evaluate the gingival response to various types of removable partial dentures
Materials and methods: 68 patients (17-49y), > 2 missing maxillary teeth. Patients with Posterior free-end RPD were not included. 28 cobalt-chromium & 40Acrylic dentures made. All partial dentures s had cast metal clasps retainers with occlusal rests. 3 types of denture-gingiva relationships: 1)gingival margin completely covered with no intentional relief, 2) gingival margin completely covered with intentional relief & 3)denture base 5-6 mm away from base of gingival margin. Measured gingival index, probing depths, gingival biopsies and bitewings taken at baseline and l week, 6 months, & 12 months after denture delivered.
Results: Most pathologic changes were in areas covered with no relief, followed by areas covered with a relief; areas not covered by the denture base were the least affected; metallic RPD bases elicited less gingival inflammation than the non-metallic bases; slightly greater probing depth in areas covered with relief than without relief (due to hyperplasia & coronal gingival proliferation); no radiographic changes could be detected during the 1^st year study period.
Discussion: the increase in the degree of inflammation could be due to mechanical pressure & bacterial colonization at the dento-gingival junction; there was an increase in the thickness of the epithelium probably due to physiologic adaptation, edema of the tissue & body irritation & the thickness of keratin because of inflammation of the connective tissue.
Conclusion: Gingival health was adversely affected by RPD’s. The degree of inflammation varied according to the denture-gingiva relationship and denture base material.
 

Wright 1995                     ARTICLE
Purpose: To evaluate whether patient and denture characteristics influence the level of gingival recession and if there is a difference in the extent of gingival recession between individuals wearing and not wearing dentures, in a given period of time.
Materials and methods:
146 pts (56-88 yrs old) with at least 12 teeth were initially examined and recalled 3 years later. 127/146 pts were re-examined to determine relationships among RPDs, their design (tissue supported vs tooth supported), and gingival recession on lingual/palatal surface

Results:
54.8% of the pts wore RPDs, 1.4% wore maxillary complete denture. Data on gingival recession: 78% of denture wearers available for 2nd exam with mean gingival recession 0.63 at the initial exam and 1.19 at the second exam. In those not wearing dentures the mean recession was 0.42mm and 0.55 for the second exam.
Discussion:
This study supports a relationship b/w the presence of a RPD and an increase of gingival recession, but was unable to demonstrate any predictable consequence of the lack of tooth support, the material used for the dentures, or covering the gingival margins with lingual plates. These design factors may be less important than the maintenance of good oral hygiene for the prevention of periodontal disease in patients wearing removable partial dentures

BL: RPD wearers are more prone to recession
 

Hansen 1997                     NO ARTICLE
P: To address considerations of RPD design which involve perio compromised teeth

Disc: Authors recommend some modifications of traditional RPD design when restoring the function of perio-involved teeth. Recommendations include:
(1) Multiple rests to ensure adequate vertical support on the event that primary abutment teeth are lost- ledges or ball shaped rest seats may be required on anterior teeth to avoid occlusal interferences
(2) Open base lattice or closed base minor connector placed in the max major connector near questionable teeth to facilitate the replacement of subsequently lost teeth. The most palatal coverage as possible, the better in order to facilitate distribution of forces.
(3) Finish lines can be modified to provide a smoother resin-to-metal transition when post teeth are lost
(4) Wire direct retainers that provide more physiologically acceptable clasping of compromised teeth. Extra: place the clasp as apical as possible- decreases the mechanical leverage.
 

7. What kind of splints exist? How does splinting affect the periodontium? What is the relationship between splinting and mobility? When do we offer splinting as part of restorative treatment?

Glickman 1961                     NO ARTICLE                        concepts and indications for splinting teeth
P: To compare the transmission of occlusal forces among splinted and non-splinted teeth
M&M: 5 adult rhesus monkeys were used, one of which served as a control. The experimental animals had gold crowns splinted or not splinted on various teeth with gold crowns cemented on opposing arch so as to increase the occlusal force and to direct the forces along a particular access. Animals were sacrificed at 10, 21, 92, and 132 days, jaws were fixed in formalin and prepared for light microscopy.
Result:
When an excessive occlusal force was applied to one tooth in a splint the periodontal tissues of all of the splinted teeth suffered comparable injury.
The injurious effect of excessive occlusal forces upon nonsplinted teeth was not transmitted to the adjacent teeth.
The bifurcation and trifurcation are the areas of the periodontium which are most susceptible to excessive occlusal forces applied in a mesioapical or distoapical direction.
The position of the epithelial attachment and the gingival fibers on the root surface was unchanged. No pocket formation was observed.
BL: When one of the teeth in a splint is subjected to excessive occlusal force the remaining teeth share the load and may suffer comparable injury.
 

Kegel 1979                     ARTICLE
P: To determine if splinting of teeth aided in reduction of mobility of posterior teeth during initial preparation.
M&M: Splinted vs. non-splinted teeth compared in a split mouth study of 7 patients with chronic periodontitis, at least two teeth in each sextant having grade 1 mobility or greater, bilaterally similar bone loss. Initial therapy included OHI, SC/RP, occlusal adjustment and splinting using intracoronal wire and acrylic splint. Tooth mobility and gingival inflammation were recorded in all 4 segments every 3 weeks for 17 weeks, with splints removed before each recording. OHI and prophy were repeated every 2 weeks.
R/BL: No difference between splinted and non-splinted teeth regarding mobility.  Both showed reduction due to improved occlusal relationship and decreased inflammation.
 

Serio 1999                     ARTICLE
Purpose: Clinical rationale for tooth stabilization and splinting.
Splint: is any apparatus, appliance, or device employed to prevent motion or displacement of function or movable parts.
Splinting: tying teeth together to increase the stability of an entire unit.
Types of splinting: 1) Temporary (less than 6 months). 2) Provisional (months to several years). 3) Permanent (long-term stability).
Materials: 1) Bonded composite resin button 1 tooth to another. 2) A-splints: prep channel in occlusal or lingual of adjacent teeth + wire. 3) Braided wire & composite extracoronal splints. 4) Acrylic resin, removal splints to control occlusal forces from bruxism. 5) Fixed splints, conventional fixed prosthodontic appliance or resin-bonded (Maryland bridge).
Effects: stabilizing effects are transient. Does not help with mobility. In absence of inflammation, possible to maintain periodontally compromised teeth long term.
Indications and possible approaches for splint therapy: 
1. Control of forces of parafunction or bruxing: acrylic biteguard/Hawley with anterior biteplane
2. Stabilization of mobile teeth for comfort: temporary, provisional, or permanent.
3. Stabilization of teeth during surgery, especially regenerative therapy: braided wire + composite/ reinforced ribbon + resine splint/biteguard.
4. Cross-arch stability of an intact or virtually intact natural dentition or preservation of arch integrity: permanent splint.
5. Stability of severely perio compromised teeth when more definitive treatment is not possible: in case of stable abutments, root of compromised teeth may be removed and splint may function as bridge with natural teeth as the pontic.
6. Restoration of vertical dimension of occlusion in case of posterior bite collapse
7. Prevention of eruption of an unopposed tooth: A-splint, biteguard or restore missing teeth
8. Postorthodontic retention: fix or removable retainer, cemented lingual wire.
9. Redistribution of forces along axes of teeth: reshaping the occusal tables with the appliance.
10. Stability of loose teeth to restore pt’s psychological & physical well-being: occlusal stability, restore a sense of a solid occlusion and improve esthetics.
 

8. Are tooth-retained overdentures a valid treatment option? For whom would this be a good option? What complications can be associated with this therapy?

Lauciello 1985                     ARTICLE
P: Longitudinal study to evaluate the response of the abutment teeth and their surrounding periodontium to overdenture therapy and to correlate the factor of OH and the length of the denture service to tissue response, tooth mobility and incidence of caries.
M&M: 25 males received overdenture ranging from 42-60 years of age and a total of 70 overdenture abutments were evaluated for period up to 6 years. Photographs, perio eval, and prophy bi-annually were done. Parameters measured: PI, GI, and PD, attached gingiva, mobility, caries and abutment tooth loss. Caries free teeth were selected for abutment teeth which were reduced to a convex contour ( w/ or w/o endo) about 1-2 mm supragingivally. 6 months recall visit with daily application of fluoride.
R: PD increased sig during the first four years and leveled off in the 5th and 6th years (32/70) abutment teeth made it to yr 5 and 6). Most teeth that began w/ no mobility stayed the same throughout the study. The most significant changes in PD occurred in the 3rd year and GI in 1st year. There was a progressive downgrade of periodontal parameters throughout the observation period. Attached gingiva continued to migrate apically and decrease in its width. These occurred irrespective of plaque index. 10 teeth lost due to perio dz (8) and caries (2).
C: frequent recall visits are necessary to delay overdenture abutment tooth loss from perio dz and decay. 
 
 

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