3. Surgical principles III- Extraction healing- Fresh Extraction Socket Preservation Techniques                                    

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Implants in native vs augmented bone.

• Management of Extraction Sockets (CH 12) pp 512-607. Zuhr and Hurzeler. Plastic-Esthetic Periodontal and Implant Surgery: A Microsurgical Approach. 2012, Quintessence Publishing.

1. Schropp L, Wenzel A, Kostopoulos L, Karring T. Bone healing and soft tissue contour changes following single-tooth extraction: a clinical and radiographic 12-month prospective study. Int J Periodontics Restorative Dent. 2003 Aug;23(4):313-23.

2. Araújo MG, Lindhe J. Dimensional ridge alterations following tooth extraction. An experimental study in the dog. J Clin Periodontol. Feb;32(2):212-8; 2005

3. Nevins M, Camelo M, De Paoli S, Friedland B, Schenk RK, Parma-Benfenati S, Simion M, et al. A study of the fate of the buccal wall of extraction sockets of teeth with prominent roots. Int J Periodontics Restorative Dent. Feb;26(1):19-29; 2006

4. Braut et al. Thickness of the anterior maxillary facial bone wall-a retrospective radiographic study using cone beam computed tomography. Int J Periodontics Restorative Dent 2011; 31: 125-131.

5. Burchardt H et al. The biology of bone graft repair. Clin Orthop Relat Res. (1983)

6. Heggeler JM, Slot DE, Van der Weijden GA. Effect of socket preservation therapies following tooth extraction in non-molar regions in humans: a systematic review. Clin Oral Implants Res. 2011 Aug;22(8):779-88.

7. Darby I, Chen ST, Buser D. Ridge preservation techniques for implant therapy. Int J Oral Maxillofac Implants. 2009;24 Suppl:260-71. Review.

8. Elian N, Cho SC, Froum S, Smith RB, Tarnow DP. A simplified socket classification and repair technique. Pract Proced Aesthet Dent. Mar;19(2):99-104; 2007

9. Wang HL, Tsao YP. Mineralized bone allograft-plug socket augmentation: rationale and technique. Implant Dent. Mar;16(1):33-41; 2007

10. Sclar AG. Strategies for management of single-tooth extraction sites in aesthetic implant therapy. J Oral Maxillofac Surg. Sep;62(9 Suppl 2):90-105;2004

11. Lasella JM, Greenwell H, Miller RL, Hill M, Drisko C, Bohra AA, Scheetz JP. Ridge preservation with freeze-dried bone allograft and a collagen membrane compared to extraction alone for implant site development: a clinical and histologic study in humans. J Periodontol. 74(7):990-9; 2003

12. Wood RA, Mealey BL. Histologic comparison of healing after tooth extraction with ridge preservation using mineralized versus demineralized freeze-dried bone allograft. J Periodontol 2012; 83:329-336.

13. Fiorellini JP, Howell TH, Cochran D, et al. Randomized study evaluating recombinant human bone morphogenetic protein-2 for extraction socket augmentation. J Periodontol. 2005 Apr;76(4):605-13

14. Farina R, Bressan E, et al. Plasma rich in growth factors in human extraction sockets: a radiographic and histomorphometric study on early bone deposition. Clin Oral Implants Res. 2013 Dec;24(12):1360-8.

15. Coomes AM, Mealey BL, et al. Buccal Bone Formation After Flapless Extraction: A Randomized Controlled Clinical Trial Comparing Recombinant Human Bone Morphogenetic Protein-2/Absorbable Collagen Carrier and Collagen Sponge Alone. J Periodontol. 2013 Jul 4.

16. Carbonell JM, Martín IS, et al. High-density polytetrafluoroethylene membranes in guided bone and tissue regeneration procedures: a literature review. Int J Oral Maxillofac Surg. 2014 Jan;43(1):75-84.

17. Nevins M, Mellonig JT, et al. Implants in regenerated bone: long-term survival. Int J Periodontics Restorative Dent. 1998 Feb;18(1):34-45.

18. Barone A, Orlando B, et al. A randomized clinical trial to evaluate and compare implants placed in augmented versus non-augmented extraction sockets: 3-year results. J Periodontol. 2012 Jul;83(7):836-46.

Topic: tooth extraction healing

Authors: Schropp L

Title Bone healing and soft tissue contour changes following single-tooth extraction: a clinical and radiographic 12-month prospective study

Source: Int J Periodontics Restorative Dent. 2003 Aug;23(4):313-23.

Type: Clinical

P: to assess bone formation in the alveolus and changes of the contour of the alveolar process following single-tooth extraction. a clinical and radiographic 12-month prospective study

M&M: 46 pts, mean age 45 years, referred for extraction of a maxillary or mandibular premolar or molar followed by single tooth implant treatment. 11 maxillary and 10 mandibular premolars and 9 maxillary and 16 mandibular molars were included in the study. Clinical and radiographic evaluation of the extraction site was carried out at baseline 0, 3, 6 and 12 months following the extraction. Standardized X-rays were taken.

R/C/BL

• Width of alveolar ridge reduced by 50% (5-7mm loss) during 12 month observation period

• Larger reduction seen in molar regions, more in mandible

• 2/3 of this reduction occurs within first 3 months

• Soft tissue height changes approximately 1mm or less

Topic: Extraction

Authors: Araújo MG, Lindhe J.

Title: Dimensional ridge alterations following tooth extraction. An experimental study in the dog. Source: J Clin Periodontol. 2005 Feb;32(2):212-8.

Type: Experimental study

Rating: Good

Keywords: Extraction

Purpose: To study dimensional alterations of the alveolar ridge that occurred following tooth extraction as well as processes of bone modelling and remodelling associated with such change.

Method: 12 mongrel dogs were included in the study. Sulcular incision performed on the 3rd and 4th premolars. Small buccal and lingual full thickness flaps were elevated. Teeth were hemisected. The distal roots were removed. The extraction sites were covered with the mobilized gingival tissue. The dogs were sacrificed at 1, 2, 4 and 8 weeks of healing and tissue blocks containing the extraction socket were dissected. The sections were examined in the microscope.

Results: The most dimensional alterations occurred during the first 8 weeks following the extraction of mandibular premolars. At this interval there was a marked osteoclastic activity resulting in resorption of the crestal region of both the buccal and the lingual bone wall. The reduction of the height of the walls was more pronounced at the buccal than at the lingual aspect of the extraction socket. The height reduction was accompanied by a ‘‘horizontal’’ bone loss that was caused by osteoclasts present in lacunae on the surface of both the buccal and the lingual bone wall. The resorption of the buccal/lingual walls of the extraction site occurred in two overlapping phases. Phase 1: the bundle bone was resorbed and replaced with woven bone. Since the crest of the buccal bone wall was comprised solely of bundle this modelling resulted in substantial vertical reduction of the buccal crest. Phase 2 included resorption that occurred from the outer surfaces of both bone walls. The reason for this additional bone loss is presently not understood.

Conclusion: The resorption of the buccal/lingual walls of the extraction site occurred in two overlapping phases. Most of this alterations occurred during the early phase, at 8 weeks post-extraction.

Topic: Ridge preservation

Authors: Nevins M, Camelo M, De Paoli S, Friedland B, Schenk RK, Parma-Benfenati S, Simion M

Title: A study of the fate of the buccal wall of extraction sockets of teeth with prominent roots.
Source: Int J Periodontics Restorative Dent. Feb;26(1):19-29; 2006

Type: Review

Rating: Good

Keywords:

Purpose: To determine the fate of thin buccal bone encasing the prominent roots of maxillary anterior teeth following extraction

Methods: 9 patients underwent extraction of 36 maxillary anterior teeth. 19 were grafted with Bio-OSS and 17 were not grafted at all. All extraction sockets were covered with soft tissue at the end of the surgery. CBCTs were taken following extraction and again at 30 and 90 days post extraction to assess the buccal plate healing. Results were assessed by an independent radiologist. 6 mm crest width was considered sufficient for an implant.

R: Sites grafted with Bio-Oss demonstrated a loss of less than 20% of the buccal plate in 79% of the test sites. Control sockets in contrast had 71% lose more than 20% of the buccal plate.

Conclusion: Bio-Oss treated sites had significantly more retention of the buccal plate. A patient has a significant benefit from receiving grafting materials at the time of extraction. It seems prudent to introduce an osteoconductive substance into the extraction sockets of teeth with prominent roots to avoid loss of buccal plate and the resulting compromises in implant treatment.

Topic: Cone Beam Computed Tomography

Authors: Braut V, Bornstein MM, Belser U, Buser D.

Title: Thickness of the anterior maxillary facial bone wall-a retrospective radiographic study using cone beam computed tomography.

Source: Int J Periodontics Restorative Dent. 2011 Apr;31(2):125-31.

Type: Retrospective Study

Rating: Good

Purpose: To analyze the thickness of the facial bone wall at teeth in the anterior maxilla based on cone beam computed tomography (CBCT) images, since this anatomical structure is important for the selection of an appropriate treatment approach in patients undergoing post extraction implant placement.

Method: A total of 125 CBCT scans met the inclusion criteria, resulting in a sample size of 498 teeth. The thickness of the facial bone wall in the respective sagittal scans was measured perpendicular to the long axis of the tooth at two locations: at the crest level (4 mm apical to the cementoenamel junction; MP1) and at the middle of the root (MP2).

Results: No existing bone wall was found in 25.7% of all teeth at MP1 and in 10.0% at MP2. The majority of the examined teeth exhibited a thin facial bone wall (< 1 mm; 62.9% at MP1,.1% at MP2). A thick bone wall (⋝ 1 mm) was found in only 11.4% of all examined teeth at MP1 and 9.8% at MP2. There was a statistically significant decrease in facial bone wall thickness from the first premolars to the central incisors. The facial bone wall in the crestal area of teeth in the anterior maxilla was either missing or thin in roughly 90.0% of patients. Both a missing and thin facial wall require simultaneous contour augmentation at implant placement because of the well-documented bone resorption that occurs at a thin facial bone wall following tooth extraction.

Conclusion: Radiographic analysis of the facial bone wall using CBCT prior to extraction is recommended for selection of the appropriate treatment approach.

Topic: Bone repair with grafting

Authors: Burchardt H et al

Title: The biology of bone graft repair

Source: Clinical Orthopaedics & Related Research, Vol 174 page 28-37,April 1983

Type: Histological study

Rating: Good

Keywords: none

Purpose: To describe biology of bone repair by presenting general information on the microscropy and correlative biomechanics of autograft repair, biological aspects of allograft repair and alternatives when autogenous bone is insufficient

Discussion:

The process of bone graft incorporation is a function of the recipient bed and depends on close contact with the donor tissue, time sequences, and the equilibrium of the following interdependent processes: 1) proliferation of osteoprogenitor cells, 2) differentiation of osteoblasts, 3) osteoinduction, 4) osteoconduction, and 5) biomechanical properties of the graft. Incorporation is defined as the process of a complex of necrotic old bone with viable new bone. The process of capillary ingrowth, perivascular issue, and osteoprogenitor cells from the recipient bed into the graft is called osteoconduction. It occurs within a framework of non biologic materials and nonviable biologic materials. In viable bone grafts, osteocondition is facilitated by osteoinductive processes and therefore occurs more rapidly than in nonviable or nonbiologic materials.

Fresh Autograft repair:

Cancellous grafts are used primarily as a means to fill small defects, whereas segments of cortical bone are used primarily as supportive struts. During the first two weeks, both cancellous and cortical autogenous materials have similar histological features.

Cancellous and cortical autografts histologically have three differences:

1) Cancellous grafts are revascularized more rapidly and completely than cortical grafts

2) Cancellous bone substitutions initially involves an appositional bone formation phase, followed by a resorptive phase, whereas cortical grafts undergo a reverse creeping substitution process;

3) Cancellous grafts tend to repair completely with time, whereas cortical grafts remain as admixtures of necrotic and viable bone.

Physiologic skeletal metabolic factors influence the rate, amount, and completeness of bone repair and graft incorporation. The mechanical strengths of cancellous and cortical grafts are correlated with their respective repair processes: cancellous grafts tend to be strengthened first, whereas cortical grafts are weakened. Bone allografts are influenced by the same immunologic factors as other tissue grafts. Fresh bone allografts may be rejected by the host's immune system. The histoincompatibility antigens of bone allografts are presumably the proteins or glycoproteins on cell surfaces. The matrix proteins may or may not elicit graft rejection. The rejection of a bone allograft is considered to be a cellular rather than a humoral response, although the humoral component may play a part. The degree of the host response to an allograft may be related to the antigen concentration and total dose. The rejection of a bone allograft is histologically expressed by the disruption of vessels, an inflammatory process including lymphocytes, fibrous encapsulation, ad peripheral graft resorption.

Topic: Ridge augmentation

Authors: Heggler Ten et al

Title: Effect of socket preservation therapies following tooth extraction in non-molar regions in humans: a systematic review

Source: Clinical oral implants research 22, no. 8 (2011): 779-788. doi: 10.1111/j.1600-0501.2010.02064.x

Type: Review

Rating: Fair

Keywords: bone loss, bone resorption, dimensional height and width changes, post-extraction socket, socket augmentation, socket preservation, systematic review, tooth extraction

Objective: To assess, based on the existing literature, the benefit of socket preservation therapies in patients with a tooth extraction in the anterior or premolar region as compared with no additional treatment with respect to bone level.

Material and methods: MEDLINE-PubMed and the Cochrane Central Register of controlled trials

(CENTRAL) were searched till June 2010 for appropriate studies, which reported data concerning the dimensional changes in alveolar height and width after tooth extraction with or without additional treatment like bone fillers, collagen, growth factors or membranes.

Results: Independent screening of the titles and abstracts of 1918 MEDLINE-PubMed and 163

Cochrane papers resulted in nine publications that met the eligibility criteria. In natural healing after extraction, a reduction in width ranging between 2.6 and 4.6mm and in height between 0.4 and 3.9mm was observed. With respect to socket preservation, the freeze-dried bone allograft group performed best with a gain in height, however, concurrent with a loss in width of 1.2mm.

Conclusion: Data concerning socket preservation therapies in humans are scarce, which does not allow any firm conclusions. Socket preservation may aid in reducing the bone dimensional changes following tooth extraction. However, they do not prevent bone resorption because, depending on the technique, on the basis of the included papers one may still expect a loss in width and in height.

Discussion: Use of regenerative biomaterial, growth factors, alternatives to ridge preservation (immediate implant placement) may be beneficial in preserving the ridge and reducing further bone loss.

Topic: Ridge Preservation

Authors: Darby I,

Title: Source: Int J Oral Maxillofac Implants. 2009;24 Suppl:260-71.

Type: review

Rating: good

Keywords: dental implants, extraction, grafting, ridge preservation, socket

P: A review of literature to evaluate the techniques and outcomes of post-ext ridge preservation (RP) and the efficacy of these procedures in implant placement.

M&M: A MEDLINE/PubMed search was conducted among articles from 1999 to March 2008, randomized clinical trials, controlled clinical trials, and pros/retrospective studies. Search lead to 37 human studies;

R:

• Materials used:

- Graft material: DFDBA, DBBM= most used

Others: autologous bone, bioactive glass, hydroxyapatite, calcium sulphate, solvent preserved cancellous allograft and biocoral

- Membranes: e-PTFE and collagen membranes = most used

Others: polylactic/polyglycolic, titanium reinforced, acellular dermal matrix graft (ADMG)

• Augmentation methods: 9 different methods were identified;

• Most Common: graft covered by membrane and flap advancement to achieve primary closure

• Second most common: coronal advancement of flap without membrane

• flap was used for all techniques w/ a membrane but not for all procedures with graft or sponge

• Outcomes of RP:

• Graft vs. Clot alone: all showed significantly better maintenance of ridge width compared to healing by clot alone. reported less change in soft tissue thickness vs. control sites

• Different Grafting Materials: slight differences between grafting materials

• Primary Closure: primary closure was hard to assess due to diversity of soft tissue closure techniques used

• Antibiotics Use: 26 of papers used ABX either during or after procedure

• Implant Placement: non-grafted sites needed augmentation procedures at time of placement

C:

• Ridge preservation procedures are effective in limiting horizontal and vertical ridge alterations in post-ext sites

• RP is accompanied by varying degrees of bone formation and residual graft materials in the ext socket. This depends on the materials and techniques used.

• There is no evidence to support the superiority of one technique over another.

• The use of membranes requires soft tissue coverage to optimize treatment outcomes. Exposure of membranes may lead to compromised results. e-PTFE membranes that become exposed ae more problematic than collagen membranes.

• Primary closure is not always necessary.

• Long-term data on stability of the ridge and implant survival and success are limited.

• There are no data on esthetic outcomes.

• There is no conclusive evidence showing that RP improves the ability to place implant.

BL: RP is effective in limiting horizontal and vertical ridge alterations in post-ext sites but there is no conclusive evidence that RP improves the ability to place implants.

Topic: Ridge Preservation

Author: Elian N, Cho SC

Title: A Simplified Socket Classification and Repair Technique

Source: Pract Proced Aesthet Dent. Mar;19(2):99-104; 2007

Type: Procedure discussion

Rating: Good

Keywords: extraction socket, buccal plate, Type II socket, noninvasive

Purpose: To present a new, simple classification of extraction sockets. To introduce an easy non-invasive approach to the grafting of sockets when soft tissue is present, but the buccal plate is partially or totally missing after extraction.

Classification of Sockets

• The key factor to determining the quality of the socket is the presence or absence of the buccal hard and soft tissue.

New Socket Classification System

Socket Repair Technique for Type II Sockets

1. Atraumatic extraction

2. The socket is debrided with surgical curettes. A finger should be placed over buccal tissue to prevent perforation of soft tissue when curetting the buccal part of socket

3. A resorbable collagen membrane is contoured into a modified V-Shape. The narrow part of the membrane is placed into the socket and should be wide enough to extend laterally past the defect in the buccal wall. The wider part of the membrane should be trimmed and be able to cover the opening of the socket following grafting

4. Membrane is positioned into the socket lining the buccal tissues. The socket is then filled with a bone graft, ideally the graft should be compressed into the socket and remain in place. Ideal graft=small-particle, mineralized cancellous freeze-dried bone allograft (0.25mm to 1mm)

   1. Compresses well, slowly resorbs, helps keep the shape of the socket

5. Top part of membrane is extended over the opening and sutured with two or three 5-0 resorbable sutures to the palatal tissue. No sutures are placed in the buccal tissue

Justification for this Technique

• Minimally invasive and because no flap is reflected or advanced coronally, there is no change in the MGJ position

• Placing the membrane inside the socket, the Periosteum is not detached from the remaining buccal plate.

• Placing membrane in socket before the graft allows for particle containment and maintains the soft tissue morphology.

BL: This minimally invasive socket repair technique has the advantage of being flapless, not distorting the buccal and interproximal tissue contours, preserving the height of the MGJ, and allowing the reformation of the buccal plate of bone. Comparison of bone levels prior to and following this treatment protocol should be a goal of future studies.

Topic: Socket Grafting

Authors: Wang H, Tsao Y.

Title: Mineralized Bone Allograft-plug Socket Augmentation: Rationale and Technique

Source: Implant Dent. Mar;16(1):33-41; 2007

Type: Clinical

Rating: Good

Keywords: Allograft, mineralized bone, extraction socket, bone regeneration

PURPOSE: To present the solvent-preserved, mineralized bone allograft-plug (Puros) for predictable socket augmentation instead of bovine hydroxyapatite bone graft (Bio-Oss), which leads to remaining hydroxyapatite crystals after 4 months of healing.

METHODS: Following atraumatic extraction and profuse bleeding is achieved with curettes or a round bur, solvent-preserved mineralized cancellous allograft (Puros) was hydrated with normal saline (or sterile water). Graft was then placed in socket and condensed to 1-2 mm below the bone level. Bioabsorbable collagen wound dressing material (CollaPlug) was gently packed on top of the bone graft material. A cross-mattress suture with 4-0 Vicryl was used on top of the collagen to achieve site stability. POI: Rinse bid with warm salt water for first two weeks, then switch to bid with chlorhexidine for 2 more weeks. Abx if indicated by current infection.

RESULTS: 2 weeks post-surgery the sockets showed uneventful healing and almost complete soft tissue coverage over the extraction site. Implant placement or stage II surgery can usually be performed at 4 months after treatment. RL persisting for more than 4 months are indicative of inadequate graft incorporation, frequently requiring an additional procedure for debridement of the graft particles and possible a new grafting procedure.

DISCUSSION: Allogenic bone graft materials have been promoted because of their availability and biologic activity compared to xenograft graft materials. While the graft by itself should be able to promote bone ingrowth, the use of a collagen plug has been shown to not only protect the graft but also induce clot formation and would stabilization.

CONCLUSION/BL: The mineralized bone allograft-plug is a suitable and predictable technique for socket augmentation to promote bone regeneration and preserve the alveolar ridge.

Sclar 2004:

Sclar AG. Strategies for management of single-tooth extraction sites in aesthetic implant therapy. J Oral Maxillofac Surg. Sep;62(9 Suppl 2):90-105;2004

Purpose: The purpose of this article is to provide information regarding the diagnosis and treatment planning as well as surgical and prosthetic management of patients faced with removal of a single tooth in an area of high aesthetic importance.

The author has reflected on systematic patient evaluation in terms of medical and dental history. And recommended special treatment planning considerations in relation to tooth malposition, periodontal bio-type, vertical maxillary deficiency, and compromised bone height or width on adjacent dentition.

The author has described the rational and details of performing the Bio-Col site preservation technique at the time of tooth removal. Its primary objective is either to preserve the osseous anatomy and scalloped soft tissue architecture in conjunction with immediate implant placement or to maintain the volume of reconstructive soft-tissue envelope and positive soft tissue architecture when subsequent site-development procedures will be unavoidable. The technique consists of atraumatic extraction of the tooth to be replaced, followed by grafting with Bio-Oss (porous bone grafting material) and isolation with an absorbable collagen membrane to promote guided bone regeneration without incorporating a flap. And the final soft tissue architecture can be maintained by using anatomic healing or custom tooth form healing abutments.

The author has developed a classification system alveolar ridge defects in aesthetic areas based on the volume and nature of the defect. Correlation of treatment options with specific defect types simplifies the selection and sequencing of indicated site-development procedures

1. Small volume soft tissue defects are corrected by subepithelial C.T grafts at implant placement.

2. large-volume soft tissue aesthetic ridge defects are usually corrected with several subepithelial connective tissue grafts before implant placement.

3. Small-volume hard tissue defects (fenestrations) that do not jeopardize the buccal alveolar crest are usually corrected with guided bone-regeneration procedures performed simultaneously with the placement of a submerged or nonsubmerged implant.

4. Large-volume hard tissue aesthetic ridge defects prevent ideal implant positioning and therefore are always reconstructed in stages using autogenous corticocancellous block and particulate cancellous bone grafts.

5. Small-volume combination hard and soft tissue aesthetic ridge defects are often camouflaged with soft tissue grafts or alloplast grafts performed simultaneously with implant placement,

6. Large-volume combination defects require staged reconstruction.

The author asserts that the use of prosthetic-guided soft tissue healing to enhance aesthetic outcomes in implant therapy by early introduction of prosthetic components that correspond to the cross-sectional anatomy of the lost tooth or the planned aesthetic replacement at the gingival level by the use of custom abutments and provisional restorations or custom tooth-form healing abutments.

Conclusion: successful management of a lost single tooth in an area of high aesthetic importance requires systematic functional and aesthetic evaluation to identify factors that could enhance the final aesthetic outcome and plan inter-disciplinary intervention.

Iasella 2003:

Iasella J, Greenwell H, Miller R et al Ridge preservation with Freeze-Dried bone allograft and collagen membrane compared to extraction alone for implant site development: A clinical and histologic study in humans. J Periodontol 2003 July; 74(7)(3): 990-9.

Purpose:

Tooth extraction leads to loss of ridge width and height. The aim of this 6-month randomized, controlled, blinded clinical study was to compare the post extraction dimensional changes following extraction alone or extraction plus ridge preservation with an intrasocket mineralized freeze-dried bone membrane (FDBM), and to determine whether there were significant differences between these two procedures. Furthermore, to determine the effect of collagen membrane on soft tissue thickness overlaying alveolar bone, as to compared to soft tissue thickness following extraction alone.

M&M:

Twenty four patients, 10 males, 14 females, ages 28 to 76, required non-molar extraction and delayed implant placement. They were selected randomly to receive either an extraction alone (EXT) or ridge preservation (RP) using tetracycline hydrated freeze-dried bone allograft (FDBA) and a collagen membrane.

Following extraction, horizontal and vertical ridge dimensions were determined using a modified digital caliper and an acrylic stent. In the RP group, FDBA was hydrated in tetracycline and placed into socket. A collagen membrane was hydrated in sterile saline for 5 minutes, trimmed and placed to cover the socket. Flaps were replaced without obtaining complete socket cover, and sutured with 4-0 silk.

All subjects were seen weekly until soft tissue closure, and then monthly until implant placement. During surgical reentry for implant placement a trephine was used to remove a core from the site, which was placed into 10% buffered formalin. These cores were prepared for histological analysis to obtain percent of cellular bone, acellular bone and trabecular spaces. An osteotomy site was prepared and each patient received a 1 or 2 stage end osseous root-form dental implant. Flaps replaced and sutured.

Results:

Width of the RP group decreased from 9.2 ± 1.2 mm to 8.0 ± 1.4 mm, while the width of the EXT group decreased from 9.1 ± 1mm to 6.4 ± 2.2 mm. This is a difference of 1.6 mm.

Both groups lost ridge width, but an improved result was found in the RP group. Most of the resorption occurred from the buccal; maxillary sites lost more width than mandibular sites.

(EXT group)

The vertical change for RP group was a gain of 1.3 ± 2.0 mm vs. a loss of 0.9 ± 1.6 mm for the EXT group. This represents a height difference of 2.2 mm.

Histologic analysis reveals more bone in RP group: 65% ± 10% vs. 54 ± 12% in EXT.

The RP group included both vital bone (28%) and non vital (37%) FDBA fragments.

Conclusion:

Ridge preservation using FDBA and a collagen membrane improved ridge height and width dimensions when compared to extraction alone. These dimensions may be very suitable for implant placement, especially in areas where loss of ridge height would compromise esthetic result. The quantity of bone observed histologically, was greater in preservation sites, although these sites included vital and non-vital bone. The most predictable maintenance of ridge width, height and position was achieved when a ridge preservation procedure was employed.

Wood 2011:

BACKGROUND:

Allografts, such as demineralized freeze-dried bone allograft (DFDBA) and mineralized freeze-dried bone allograft (FDBA) are commonly used by clinicians for ridge preservation procedures. The primary objective of this study is to histologically evaluate and compare the healing of non-molar extraction sockets grafted with DFDBA versus FDBA for ridge preservation. The secondary aim of this study is to compare dimensional changes in ridge height and width after grafting with these two materials.

MATERIALS:

Forty patients were randomly divided into two groups of 20. Extraction sockets were filled with either FDBA or DFDBA. To minimize variables associated with the organ donor and with tissue processing, all of the graft material was procured from a single donor; the only difference in the two materials was the percentage mineralization of the final bone graft. A 2-mm-diameter core biopsy was taken from each grafted site ≈19 weeks after grafting. Histomorphometric analysis was performed to determine percentage of vital bone, residual graft particles, and connective tissue (CT)/other non-bone components.

RESULTS:

There were no significant differences when comparing changes in alveolar ridge dimensions of the two groups. There was no significant difference in percentage CT/other between groups. DFDBA had a significantly greater percentage of vital bone at 38.42% versus FDBA at 24.63%. The DFDBA group also had a significantly lower mean percentage of residual graft particles at 8.88% compared to FDBA at 25.42%.

CONCLUSION:

This study provides the first histologic and clinical evidence directly comparing ridge preservation with DFDBA versus FDBA in humans and demonstrates significantly greater new bone formation with DFDBA

Topic: rhBMP-2

Authors: Fiorellini J

Title: Randomized study evaluating recombinant human bone morphogenetic protein-2 for extraction socket augmentation.

Source: J Periodontal. April 2005, Volume 76, Number 4- 605-13

Type: Clinical

P: to evaluate the efficacy of bone induction for the placement of dental implants by two concentrations of recombinant human bone morphogenetic protein-2 (rhBMP-2) delivered on a bioabsorbable collagen sponge (ACS) compared to placebo (ACS alone) and no treatment in a human buccal wall defect model following tooth extraction.

Methods: 80 patients (43 males and 37 female) mean age of 47.4, requiring local alveolar ridge augmentation for buccal wall defects (50% buccal bone loss of the extraction socket) of the maxillary teeth (bicuspids forward) immediately following tooth extraction were enrolled. Two sequential cohorts of 40 patients each were randomized in a double-masked manner to receive 0.75 mg/ml or 1.50 mg/ml rhBMP-2/ACS, placebo (ACS alone), or no treatment in a 2:1:1 ratio. Efficacy was assessed by evaluating the amount of bone induction, the adequacy of the alveolar bone volume to support an endosseous dental implant, and the need for a secondary augmentation.

Results: Assessment of the alveolar bone indicated that patients treated with 1.50 mg/ml rhBMP-2/ACS had significantly greater bone augmentation compared to controls (P 0.05). The adequacy of bone for the placement of a dental implant was approximately twice as great in the rhBMP-2/ACS groups compared to no treatment or placebo. In addition, bone density and histology revealed no differences between newly induced and native bone.

Conclusion: the stimulation of host healing
responses with rhBMP-2 versus dependence on the osteoconductive properties of a carrier material enhanced predictability and provided a substantial patient clinical benefit.

BL: Buccal wall extraction defect model utilized to assess a combination of rhBMP-2 and a commonly utilized collagen sponge had a striking effect on de novo osseous formation for the placement of dental implants.

Topic: Extraction

Authors: Farina R1, Bressan E, Taut A, Cucchi A, Trombelli L.

Title: Plasma rich in growth factors in human extraction sockets: a radiographic and histomorphometric study on early bone deposition.Source: J Clin Periodontol. 2005 Feb;32(2):212-8.

Type: Clinical study

Rating: Good

Keywords: CD68 antigen; alveolar process; bone remodeling; growth factors; histology; osteocalcin; plasma; platelet-rich plasma; tooth extraction; von Willebrand factor

Purpose: To determine whether and to what extent the additional application of plasma rich in growth factors (PRGF) to an extraction socket may influence the early bone deposition.

Methods: Twenty-eight patients (age range: 34–74 years) contributing 36 extraction sockets were included in the study. Sockets were either treated with PRGF (PRGF group; 18 sites in 11 patients) or left to spontaneous healing (control group; 18 sites in 17 patients). Radiographic and histomorphometric analysis was performed on bone cores trephined from each healing socket after 4–6 (T1) or 7–10 (T2) weeks of healing.

Results: Patients treated with PRGF application showed: 1- similar bone volume and tissue mineral content, 2- a trend, although not statistically significant, toward a greater number of CD68+ cells (at T1 and T2) and vVW+ cells (at T1), and 3- a similar OCN staining score throughout the study, when compared with control group.

Conclusions: Plasma rich in growth factors-treated group did not show any enhancement in early (4 and 8 weeks) bone deposition compared with control group.

Topic: Ridge preservation

Authors: Coomes AM, Mealey BL

Title: Buccal Bone Formation After Flapless Extraction: A Randomized Controlled Clinical Trial Comparing Recombinant Human Bone Morphogenetic Protein-2/Absorbable Collagen Carrier and Collagen Sponge Alone.
Source: J Periodontol. 2013 Jul 4.

Type: Review

Rating: Good

Keywords:

P: To determine the effects of flapless extraction technique in combination with rhBMP-2 on a resorbable collagen sponge in extraction sites with greater than 50% buccal dehiscence

M&M: 39 patients requiring extraction op hopeless teeth with greater than 50% buccal dehiscence. Flapless extraction was performed and patients were selected at random to have a collagen sponge or a collagen sponge soaked in rhBMP-2 into the extraction site. CBCTs were obtained at baseline after extraction and again at 5 months postoperatively.

R: rhBMP-2 on a collagen sponge was able to regeneration portions of lost buccal plate, maintain ridge dimension, and allow for implant placement 5 months post extraction. The rhBMP-2 group was significantly better in clinical regeneration, clinical ridge width at 5 months, and radiographic ridge width at 3 mm from the alveolar crest (with molar exclusion). There was significantly less remaining buccal dehiscence clinically and radiographically at 5 months when compared to control. Significantly more implants were placed in the rhBMP-2 group that did not need additional augmentation.

BL: rhBMP-2 with a collagen sponge performed better than collagen sponge alone when used in flapless extraction sites with a buccal dehiscence. Results showed it was superior in regeneration of buccal plate, maintenance of ridge dimension, and allowance for implant placement 5 months later.

Topic: Membrane

Authors: Carbonell JM, Martín IS, Santos A, Pujol A, Sanz-Moliner JD, Nart J.

Title: High-density polytetrafluoroethylene membranes in guided bone and tissue regeneration procedures: a literature review.

Source: Int J Oral Maxillofac Surg. 2014 Jan;43(1):75-84

Type: Review

Rating: Good

Keywords: dense PTFE; high-density PTFE; microporous PTFE; nano-porous PTFE; non-expanded PTFE; non-permeable PTFE; non-porous PTFE

Purpose: The aim of this literature review was to analyze and describe the available literature on n-PFTE, report the indications for use, advantages, disadvantages, surgical protocols, and complications.

Method: The medical databases Medline-PubMed and Cochrane Library were searched and supplemented with a hand search for reports published between 1980 and May 2012 on n-PTFE membranes. The search strategy was limited to animal, human, and in vitro studies in dental journals published in English.

Results: Twenty-four articles that analyzed the use of n-PTFE as a barrier membrane for guided tissue regeneration and guided bone regeneration around teeth and implants were identified: two in vitro studies, seven experimental studies, and 15 clinical studies.

Conclusion: There is limited clinical and histological evidence for the use of n-PTFE membranes at present, with some indications in guided tissue regeneration and guided bone regeneration in immediate implants and fresh extraction sockets.

Authors: Nevins M, Mellonig J et al

Title: Implants in regenerated bone: long-term survival

Source: Int J Periodontics Restorative Dent. 1998 Feb;18(1):34-45.

Type: Restrospective study

Rating: Good

Keywords: none

Purpose: Evaluate the long-term success of implants in function in bone regerated by GBR combined with an autograft or allograft

Methods and Materials: Both autogenous and allografts (FDBA) were used in combination with a barrier membrane (e-PTFE) to reconstruct bone using either a simultaneous or staged approach. Different implant systems were used. Subjects were followed from 6 to more than 74 months post loading (single and multiple unit prosthetics). Periapical radiographs taken to evaluate implant health and bone quality at follow up evals. Patients were seen at 6 months, 1 year, and annually after placement.

Results: Eight of the implants were lost, for a success rate of 97.5% (all implants placed in maxilla, occlusal loading presumed etiology of failure). Mean cumulative bone loss as determined over 74 months of loading was 0.64mm. Least amount of bone loss was seen in those sites without any complication from infection.

Conclusion: Regenerated bone reacted to implant placement in a manner that was clinically similar to native bone. The type of graft material did not affect the clinical success of the implants, nor did the use of submerged versus non-submerged implants nor a staged versus a simultaneous approach. This correlates with other studies that report 98.6% success in grafted sites.

Topic: Ridge augmentation

Authors: Barone Antonio et al

Title: A Randomized Clinical Trial to Evaluate and Compare Implants Placed in Augmented Versus Non-Augmented Extraction Sockets: 3-Year Results

Source: Journal of periodontology, 83(7), 836-846. doi: 10.1902/jop.2011.110205

Type: Controlled clinical trial

Reviewer: Jyoti Sonkar

Rating: Good

Keywords: Alveolar bone loss, bone substitutes, dental implants, survival rate

Background: The alveolar ridge undergoes reabsorption and atrophy subsequent to tooth removal and thus exhibits a wide range of dimensional changes. Preservation of the alveolar crest after tooth extraction is essential to enhance the surgical site before implant fixture placement.

Aim: To investigate and compare the need for additional augmentation procedures at implant insertion, as well as the success rate and marginal bone loss for implants placed in the grafted sites versus those placed in naturally healed sites.

Methods: Forty patients with >1 hopeless tooth were randomly allocated to: 1) a test group, receiving extraction and grafting corticocancellous porcine bone; and 2) a control group, receiving extraction without any graft. After 7months of healing, implants were inserted in each of the sites. The implants were submerged and loaded after 4 months with metal–ceramic rehabilitation. The follow-up included evaluation of implant diameter and length, the need for additional augmentation procedures at implant placement, implant failure, and marginal bone level changes. All patients were followed over a 3-year period.

Results: One implant failed in the control group at the second stage of surgery (6 months after placement); one implant failed in the test group after 2 years of loading. The cumulative implant success rate at the 3-year follow-up visit reached 95% for both groups. No statistically significant differences were detected for marginal bone changes between the two groups.

Conclusion: The results of the present study show that there were no differences in the survival rates between implants placed into augmented and non-augmented sites. However, grafted sites allowed placement of larger implants and required less augmentation procedures at implant placement when compared to naturally healed sites.