Quick Search Terms
What is group function? What is canine guidance? Which type of occlusion is most common?
Neiburger EJ. The evolution of human occlusion - Ancient clinical tips for modern denetists. General Dent Jan-Feb:44-49, 2002.
D'Amico A. Functional occlusion of the natural teeth of man. J Prosth Dent 11:899-915, 1961
Alexander PC. Analysis of the cuspid protected occlusion. J Prosthet Dent 13:309-317, 1963
Akoren AC, Karaagaclioglu L. Comparison of the electromyographic activity of individuals with canine guidance and group function occlusion. J Oral Rehabil 22:73-77,1995.
Analysis
Graf H, Zander HA. Tooth contact patterns in mastication. J Prosth Dent 13:1055-1066, 1963.
Pameijer J, et al. Intraoral occlusal telemetry, III. Tooth contacts in chewing, swallowing, and bruxism. J. Periodontol. 40:253-258, 1969.
Carwell ML, McFall Jr. WT. Centric relation determinations: clinical and radiographic comparisons. J. Periodontol. 52:347-353, 1981.
How is occlusal adjustment performed? Does occlusal adjustment lead to attachment level gain? Is occlusal adjustment indicated? When ? Does occlusal adjustment improve the prognosis of periodontal treatment ? When should occlusal trauma be treated in the normal sequence of periodontal therapy? Why? What technique do you use in your practice to adjust the occlusion? Defend that philosophy.
In Our Opinion:" When and to what extent do you adjust the occlusion during periodontal therapy? J. Periodontol. 41:536-541, 1970.
Vale JDF, Ash MM Jr. Occlusal stability following occlusal adjustment. J Prosthet Dent 27:515-523, 1972.
Moozeh MB, et al. Tooth mobility measurements following two methods of eliminating nonworking side occlusal interferences. J. Clin. Periodontol. 8:424 -430, 1981.
Hakkarainen K, Uitto V-J, Ainamo J. Collagenase activity and protein content of sulcular fluid after scaling and occlusal adjustment of teeth with deep periodontal pockets. J. Periodontal Res. 23:204-210, 1988.
Burgett F. et al: A randomized trial of occlusal adjustment in the treatment of periodontitis patients. J Clin Periodontol 1992;19:381-387
Lindhe J., Nyman, S., Ericsson, I. Trauma from occlusion: Periodontal tissues. In: Lindhe et al.. Clinical Periodontology and Implant Dentistry, ed 5., Oxford, UK: Blackwell Munksgaard, 2008:359
Should parafunctional habits be managed as part of periodontal therapy ? Does bruxism and/or its management affect the occurrence or prognosis of periodontal disease? What are the symptoms of bruxism? Can periodontal disease be affected by bruxism?
Rugh JD, Barghi N, Drago CJ. Experimental occlusal discrepancies and nocturnal bruxism. J. Prosthet. Dent. 51:548-553, 1984.
Clarke NG, Townsend GC, Carey S.: Bruxing patterns in man during sleep. J Oral Rehab. 11: 123-127, 1984.
Kydd WL, Daly C: Duration of nocturnal tooth contacts during bruxing. J. Prosthet. Dent. 53:717-721, 1985.
Hanamura H, Houston F, Rylander H, et al. Periodontal status and bruxism - a comparative study of patients with periodontal disease and occlusal parafunctions. J Periodontol. 58:173-176, 1987.
Discuss buttressing bone
Glickman I, Smulow JB. Buttressing bone formation in the periodontium. J Periodontol 36: 365-370, 1965.
What are the options for treatment of bruxism?
Ayer W, Levin M : Theoretical basis and application of massed practice exercises for the elimination of tooth grinding habits. J. Periodontol. 46: 306-308, 1975.
Kardachi BJR, Bailey JO, Ash MM : A comparison of biofeedback and occlusal adjustment on bruxism. J. Periodontol. 49:367-372, 1978.
Okeson J. The effects of hard and soft occlusal splints on nocturnal bruxism. JADA 114: 788 , 1987.
Pierce C, Gale E: A comparison of different treatments for nocturnal bruxism. J Dent Res 67:597-601, 1988.
Holmgren K, Sheikholeslam A, Riise C. Effect of a full-arch maxillary occlusal splint on parafunctional activity during sleep in patients with nocturnal bruxism and signs and symptoms of craniomandibular disorders. J Prosth Dent 1993; 69:293 -297.
Tarantola GJ, Becker IM, Gremillion H, Pink F. The effectiveness of equilibration on the improvement of signs and symptoms in the stomatognathic system. Int J Perio Rest Dent 18:595-603,1998.
Reviews
Zander HA, Polson AM: Present status of occlusion and occlusal therapy in periodontics. J.Periodontol. 48:540-544, 1977. (Review)
Berglundh T, Abrahamsson I, Lindhe J. Bone reactions to longstanding functional load at implants: an experimental study in dogs. J Clin Periodontol 2005 Sep;32(9):925-32.
What is group function? What is canine guidance? Which type of occlusion is most common?
P: To present a historic definition of normal occlusion and evidenced-based recommendations established by our evolutionary history.
D: “Normal” occlusion, is the result of man’s evolution. Important factors are 1) heredity and 2) environment. Early humans and many present-day residents of third-world (“developing”) nations chewed and lived with flattened, well worn teeth. This is called “flat plane occlusion”. Here teeth have low cusps and shallow fossas. Interproximal areas are worn nearly flat, so there are broad contact surface areas. Interproximal distances between teeth is reduced. There is essentially no canine rise and little incisal guidance. The bite often slipped into an edge-to-edge relationship in which centric occlusion becomes centric relation. Flat plane occlusion reduces prematurities and traumatic occlusions, low or non-existent fractures or cracked cusp syndrome. The mandible is free to move unrestricted, reducing stress on individual teeth and the TMJ. Tooth mal-alignments are rare. There is no apparent loss in nutrition due to reduced efficiency. Disadvantages of this scheme include a loss in vertical dimension and potential pulp exposures. The author is not in favor of “cuspal occlusion” (more problems such as TMJ, caries and periodontal disease). He recommends when restoring teeth that the clinician utilizes shallow anatomy, low cusps, broader contact areas instead of contact points, strip interproximal contacts, encourage patients with common TMD or bruxism to gently chew stiff fibrous materials, and consider the age of the patient. Clinicians should follow the patient’s physiology and jaw movements rather than depending on artificial programs or measuring devices.
BL: Evolutionary history prescribes flat plane occlusion.
D'Amico 1961 ARTICLE
P: Review of the evolution and function of the natural teeth of man.
Disc: Discusses the theory of balanced occlusion, attrition, occlusal forces and mechanics to
show that proper occlusal corrections can be made during early stages of life, to reduce the percentage of extractions necessitated by the failure of the periodontium.
The evidence obtained from skull studies of aboriginals and native California Indians, does not
support Von Spee’s theory of balanced occlusion (1890). Up to the age of maturity, periodontal lesions that result from traumatic occlusion are rarely seen, but later, failure of osteoblasts to keep pace, gradually results in progressive resorption of alveolar bone. Proper occlusal corrections can be made if deviations from the ideal functional relation of the natural teeth are detected during early stages of life.
Proponent of cuspid protected occlusion, with canines disoccluding posterior teeth in lateral movements. Cuspid use protects posterior teeth from horizontal forces generated by detrimental contacts. Long roots and relatively greater proprioception makes the canine best suited for this role.
Alexander 1963 ARTICLE
P: To offer a hypothesis that group function, as opposed to canine guidance, satisfies the
functional requirements of the periodontal tissues.
Conclusions:
The balanced occlusion theory is supported by histologic, physiologic, biologic, & clinical evidence. The continuous eruption of teeth and the relative stability of the vertical relation of rest position is supported by cephalometric, clinical and electromyographic studies. The role of the canine tooth is to function in unison with remaining teeth. The proprioceptive response is the same throughout all teeth in the mouth. Restoring of the lingual surface of the maxillary canine to function alone in eccentric movements is contraindicated. The development of edge-to-edge occlusion is unacceptable as it refutes the relative stability of the rest of the vertical dimension & the continuous eruption theory, which is a compensatory reaction to tooth wear. The canine should not needlessly be placed in jeopardy simply because it can withstand greater forces than other teeth.
BL: Group function distributes forces more optimally, preventing occlusal trauma on the
canines, which could lead to TMJ problems.
Cr: historical article; purely empirical
Akoren 1995 ARTICLE
Purpose: To test the effect of two different occlusal schemes on masseter and anterior temporal muscles during gum chewing and sliding laterally by using electromyography and surface electrodes.
Materials and methods: 30 subjects 17-25 years old with healthy functional occlusion and no dysfunction. 15 subjects in each group (canine guidance and group function). Electromyographic data were obtained during gum chewing (both sides) and then during sliding from centric relation to laterally for both groups (only working side muscles).
Results: No SSD between two groups during gum chewing in microvoltage values. In group function the anterior temporalis muscle was more active during sliding. Narrow chewing model was observed with canine guidance and wide with group function.
Conclusion: Both occlusal schemes can be used for patients that lost their natural occlusion. In case of healthy canine teeth with good support, canine guidance occlusion is advantageous because of: 1) the narrow chewing model with the mandible being directed vertically to centric occlusion and 2) the reduction of activity of anterior temporal muscle during lateral slide from centric relation.
Graf 1963 ARTICLE
Purpose: To investigate whether or not tooth contact occurs in the intercuspal position (ICP) and /or retruded contact position (RCP) during mastication and swallowing.
Materials and methods:
5 adults with healthy TMJ and periodontium and normal occlusion, each had 3 bridges with radio transmitter pontics placed reproducing their original occlusal morphology.
ICP and RCP were recorded during mastication and swallowing. Motion picture sequences of several eating acts were taken at 24 frames/sec.
Results:
Teeth contact in ICP during mastication and swallowing food.
Tooth contacts in RCP occur only during swallowing and cleansing.
The frequency, duration, and distribution of these tooth contacts during mastication made up an individual pattern for each of the subjects of the study.
Pameijer 1969 ARTICLE
Purpose: To study tooth contacts during chewing, swallowing, and bruxism using a
multifrequency intra-oral telemetric system incorporated in posterior bridges.
M&M: Recordings were performed on six adults with one missing molar. Miniature transmitting devices were built into 2 interchangeable bridges which replaced the missing molar without interfering with the occlusion. Switch was positioned in sagittal plane in 1 bridge and in coronal plane in other. Protrusive, retrusive, right & left lateral single tooth contacts and glides movements were compared to the frequency, duration of tooth contacts in centric and in habitual occlusion. Recordings were made with subjects eating hamburgers and bruxing.
Results: Centric occlusion was seldom used in chewing and swallowing. Most chewing and swallowing occurred in habitual occlusion (functional occlusion). Lateral excursions are not typical of the chewing cycle. Contacts during mastication are haphazard, while those occurring during bruxism are regular and repetitive.
BL: Bruxism is a specifically directed neuromuscular phenomenon rather than a simple accentuation of the normal mastication. Habitual occlusion is really the working occlusion during mastication (position in which the teeth contact most often in chewing & swallowing)
Carwell 1981 ARTICLE
P: Investigated variations in occlusal prematurities and condylar positions using the following CR determination methods: 1) bilateral mandibular manipulation (BMM); 2) chin point method (CPM); 3) CPM with anterior jig (CPJ) method. Condylar position was determined with tracing evaluations and direct measurements of the radiographs.
M&M: The study included 30 adults (21-63 y.o). 17F & 13M. Criteria: at least 24 teeth including all premolars and 1st, 2nd molars, neg. Hx of TMD, and no occlusal adjustment by selective grinding. The manipulation were repeated and the anterior and lateral components of the slide form CR to CO measured using CPM and BMM. the presence of the jig prevented accurate measurement of the slide with the CPJ. The parameters recorded were nonfunctional contacts within the path of lateral excursions, jaw relationship using Angle's system, group function vs. cuspid guidance, measurement of PD, calculus & gingivitis. Standardized transcranial oblique X-ray were taken of each TMJ using CPM and BMM on 10pts (4F, 6M)
R: 87% Angle Class 1 occlusion, 47% bilateral cuspid guided occlusion, 27% group function, 90% had CR-CO slide, and increase in group function w/an increase in age. Location of CR contacts on same teeth were clinically identical using all 3 techniques. Clinical results indicated that the initial point of contact was located most accurately with CPJ. Both initial contact points and secondary points are disclosed with CPM .Total # of contacts greatest with BMM and least w/CPJ. No measurable or tracing difference of condyle position in TMJ radiogrphs using CPM and BMM. Radiographic analyses of condylar position were inconclusive.
BL: Location of CR on the same teeth were clinically identical with the 3 techniques. Bilateral manipulation produced the greatest number of contacts . CR prematurities occurred most frequently on first premolars. Periodontal status of teeth with CR contacts was not significantly different from those without. Second molars were responsible for the majority (56%) of balancing interferences. Radiographic eval showed no differences in condyle position b/t BMM and CPG.
How is occlusal adjustment performed? Does occlusal adjustment lead to attachment level gain? Is occlusal adjustment indicated? When ? Does occlusal adjustment improve the prognosis of periodontal treatment ? When should occlusal trauma be treated in the normal sequence of periodontal therapy? Why? What technique do you use in your practice to adjust the occlusion? Defend that philosophy.
In our opinion 1970 No ARTICLE
P: When and to What Extent Do You Adjust the Occlusion during Perio Therapy?
Glickman: 1) Preventive occlusal adjustment (OA): NOT recommended 2) Occlusion should usually be adjusted after inflammation is eliminated (teeth tend to be displaced by inflammation). 3) Infrabony pockets or mucogingival surgery: adjust before or at treatment. 4) Mobility due occlusal trauma: adjust before or at treatment. 5)Temporary splints: adjust before splinting & after inflammation is eliminated. 6) Occlusal adjustment should shift from CO and lateral excursions to focus on functional occlusion (habitual or acquired occlusion).
Ratcliff: 1) Preventive OA: NOT recommended. 2) The definitive clinical diagnosis of trauma is impossible. 3) There is little or no scientific evidence to support any specific tx. 4) OA can be justified to improve the hygiene of the mouth. 5) Pain is the only justification of OA for periodontal therapy purposes. 6) Persist in extensive OA doesn’t prevent successful periodontal treatment when adequate level OH is maintained.
Sugarman: 1) Preventive OA: NOT recommended. 2) OA: Only when there is evidence of occlusal trauma (OT) (mobility, radiographic findings of thickened lamina dura or widened PDL spaces). 2) Trauma is trauma only when it produces pathology. 3) OA is contraindicated for: Displaced teeth, overbite, loss of VD and open contacts, abraded teeth. 4) Still mobility after grinding and perio tx: Use a biteguard for stabilization. 5) If needed OA: adjust prior to surgery, removing balancing interferences and centric prematurities. 6) Teeth with healthiest support should carry greatest load in lateral excursion (LE). 7) All teeth should contact at least 1 point in CO. 8) When post teeth are periodontally involved: canine guidance is preferred. 9) When all the teeth are periodontally involved: group function is preferred. 10) Single tooth involved: Leave only CO contact, eliminate LE and protrusive contacts. 11) Not all angular defects should have OA.
Helmut: 1) Preventive OA: NOT recommended. 2) No rule regarding the timing of OA. 3) Increased mobility wo excessive bone loss: OA first. 4) If inflammation and excessive bone loss are present: OA at or after perio tx. 5) The extent of occlusal adjustment depends on the extent of occlusal disharmonies. 6) Only occlusal disharmonies that causes trauma should be address. 7 ) Polish the surface that was adjusted.
Vale 1972 ARTICLE
P: To determine if an occlusal adjustment technique based on the principle of occlusal stability (by Ramfjord & Ash) will result in shifting or movement of teeth.
M&M: Used stereophotogrammetry to assess tooth stability following occlusal adjustment over 90 days in 8 patients. 8 patients with: 1) 80% of posterior teeth were opposed in CO in Max. and Mand. jaws, 2) no fixed or removable appliances, 3) at least 18 years old, and 4) no clinical perio disease. Stone casts were made at occlusal adjust., 6 weeks, & 12 weeks. Reference points made using 1/2 round bur on fillings. 3D picture of casts were made using Cotter photographic system with occlusal surfaces facing perpendicular to camera (through calibrated glass grid). These photographs were taken in two different positions and tooth points and reference points were used to create a three dimensional representation. Differences between the tooth points and reference points were calculated.
R: Distances between tooth points & reference points were analyzed and found to be not SS (p>0.20). The study indicates that occlusal adjustment provides stability up to 0.1 mm, but shifting could have occurred which the system could not detect (error ±0.106 mm).
CL: Tooth position (contacts) didn’t change significantly over 90 days. Max change-0.1mm. Tooth movement is not an unavoidable result of occlusal adjustment according to principle of providing or maintaining occlusal stability. Stereophotogrammetry is suitable for measuring teeth movement of + 0.106 mm. In order to determine shifting of teeth all teeth would have to be evaluated and at shorter intervals.
Comment: Limitation that a tooth might shift immediately after occlusal adjustment & shift back to original position before observation. Future studies with closer observation & more subjects indicated.
Moozeh 1981 ARTICLE
P: Quantitative assessment of tooth mobility following 2 methods of eliminating non-working side interferences (NWI): a) total elimination of any tooth contact on the nonworking side or b) elimination of interferences but maintaining tooth contacts on the non-working side.
M&M: 33 patients (18M/15F, 20-56 years) participated in the study. Patients had non-working interferences, no signs of trauma from occlusion, no history of grinding or clenching and no previous occlusal adjustment. At the beginning of the experiment all patients received prophy and OHI. Gingival health was monitored throughout therapy. Tested mobility of teeth with non-working interferences with microperiodontometer (A force of 500g was applied 3 times on the facial and lingual displacements were recorded) and took x- rays for bone level and PDL comparison. Divided patients into 3 groups: 1) total elimination of NWI, 2) NWI were eliminated in such a manner as to maintain light contacts on the non-working side. These light contacts were checked by occlusal registration strips 3) control group: no occlusal adjustment. 2 months later mobility and bone height measurements were repeated
R: Mobility changes: Group 1 had significantly greater decrease in mobility than group 2 (8.2% vs 3.6%). Control group presented an increase in mobility (1.1%). No change in bone levels or PDL widths for any of the treatments.
BL: No changes in bone height or PDL width were noted in any group. The group in which interferences were totally eliminated showed an 8.2% decrease in mobility, groups where interferences were reduced to contacts showed a 3.6% decrease in mobility. Control group (no adjustment) showed a 1.1% increase in mobility.
Hakkarainen 1988 ARTICLE
P: To determine the protein content and collagenase activity of GCF from deep infected periodontal pockets of hypermobile teeth before and after SRP and occlusal adjustment.
M+M: 3 teeth from 14 pts (5F, 9M, mean age 49) with localized severe periodontal disease.
Test tooth : An incisor or canine with increased mobility associated with occlusal interference and > 5 mm pocket.
2 controls: Infected control tooth nonmobile incisor or canine with > 5 mm pocket
Healthy control tooth nonmobile incisor or canine with < 3 mm pocket.
At least 7 days prior to experimental period, OHI and prophy were given. 7 subjects (Group A) had SRP only, the other 7 had occlusal adjustment (Group B).
At day 14, the treatment was reversed (Group A had occ adjustment and Group B had SRP).
PDs, GI, mobility score, and GCF collection (paper strips) for assay of protein content and collagenase activity were collected at 0, 7, 14 and 28 days.
R: Protein content and collagenase activity in deep pockets was elevated during periodontitis in both mobile and immobile teeth. NSSD decrease of protein content and SSD decrease of collagenase activity took place following SRP. SSD decrease in both protein content and collagenase activity was seen after occlusal adjustment. No changes seen with controls. No change seen in mobility or mean GI in any groups.
BL: Whether teeth are mobile or immobile, periodontal disease increases collagenase activity and protein content. Occlusal adjustment can slightly decrease collagenase activity and protein content, however SRP significantly augments this effect.
Burgett 1992 ARTICLE
P: To test: 1) the influence of occlusal adjustment in association with perio therapy on CAL, PD, and mobility 2) whether the effects of occlusal adjustment differend in non-sx tx vs sx-treated pockets 3) whether intial mobility had an influence on the perio response to occlusal adjustment
M&M: randomized trial of occlusal adjustment on 50 moderate-advanced perio pts (age 25-69). 22 pts received an occlusal adjustment and 28 were not adjusted. Two months after the occlusal djustment, each pt randomly received either a MWF sx of SRP in a split mouth design. Following active tx, pts were maintained with prophylaxis done every 3 months. Pts completed 2-yr follow-up
Results/Conclusion: Mean CAL responded more favorably in the pts who received occlusal adjustment than in the non-adjusted pts (SS dif in sites with 4-6mm ALoss). There was NSSD in pocket response between adjusted and non-adjusted pts. Both the sx and non-sx tx sites of the mouth responded similarly to the occlusal adjustment. Initial mobility and initial severity of perio dz did not affect the CAL response to occlusal adjustment. There was NSSD between groups with respect to mobility, even though one group had occlusal adjustment.
Cr: The difference in AL was 0.4mm in between the O adjustment and non-occlusal adjustment group at 1 and 2 yrs (no change). Only 0.1mm difference in PD response between groups. Most likely not clinically significant. Only one examiner.
Lindhe, Nyman, Ericsson 2008 Textbook NO ARTICLE
Definition: Trauma from occlusion: pathologic alterations or adaptive changes which develop in the periodontium as a result of undue force produced by the masticatory muscles. It can cause damage in the periodontal tissues and in the TMJ, the masticatory muscles and the pulp. It is divided in primary, which includes a tissue reaction around a tooth with normal height of the periodontium, and secondary that is related to situations in which occlusal forces cause injury in a periodontium of reduced height.
Findings from human autopsy material: Assessments made in specimens from cadavers have a limited value when “cause–effect” relationships between occlusion, plaque, and periodontal lesions are to be describe, therefore results are controversial.
Glickman’s conept: nstead of an even destruction of the periodontium and alveolar bone (suprabony pockets and horizontal bone loss), which, according to Glickman, occurs at sites with uncomplicated plaque-associated lesions, sites which are also exposed to abnormal occlusal force will develop angular bony defects and infrabony pockets.
The periodontal structures can be divided into two zones:
1. The zone of irritation: the marginal and interdental gingiva, where gingival inflammation cannot be induced by trauma from occlusion but is the result of irritation from microbial plaque
2. The zone of co-destruction: includes the periodontal ligament, the root cementum, the alveolar bone and is coronally demarcated by the transseptal and the dentoalveolar collagen fiber bundles. The tissue in this zone may have a lesion cause by trauma from occlusion. Fiber bundles are exposed to alteration coming from both zones and alter the normal pathway of inflammation which results in angular bony defects.
Waerhaug’s concept: Measured the distance between the subgingival plaque and the periphery of the associated inflammatory cell infiltrate in the gingiva, and the surface of the adjacent alveolar bone. He found that angular bony defects and infrabony pockets occur equally often at periodontal sites of teeth which are not affected by trauma from occlusion as in traumatized teeth. He concluded that angular bony defects and infrabony pockets occur when the subgingival plaque of one tooth has reached a more apical level than the microbiota on the neighboring tooth, and when the volume of the alveolar bone surrounding the roots is comparatively large.
Clinical trials: Philstrom (studied max 1st molars clinically and radiographically) found that teeth with increased mobility and widened periodontal ligament space had, deeper pockets, more attachment loss, and less bone support than teeth without these symptoms.
Burgett studied the effect of occlusal adjustment in the treatment of perio. And found that patients that received both perio treatment and occlusal adjustment gained 0.5mm more AL.
Nunn and Harrel examined the relationship between occlusal discrepancies and periodontitis. It was observed that teeth with occlusal discrepancies had significantly deeper PDs and higher mobility scores than teeth without occlusal trauma and also that teeth that had occlusal adjustment responded better to non-surgical periodontal therapy than teeth with remaining occlusal discrepancies.
Neiderud, in a dog study demonstrated that tissue alterations which occur at mobile teeth with clinically healthy gingivae may reduce the resistance offered by the periodontal tissues to probing (leading to deeper PDs clinically).
Animal experiments: If the crown of a tooth is affected by horizontally directed orthodontic forces, the tooth tends to tilt in the direction of the force. This results in the development of pressure and tension zones within the marginal and apical parts of the periodontium. The tissue reactions in the pressure zone are characterized by increased vascularization, increased vascular permeability, vascular thrombosis, and disorganization of cells and collagen fiber bundles. If forces are within certain limits bone resorption occurs on the pressure side (direct bone resorption). If the forces are higher bone necrosis (hyalinization) occurs and bone resorption (indirect) happens to adjacent surrounding bone. Bone apposition happens in the tension zone in order to maintain the normal width of the PDL. The tooth becomes mobile and when it moves to a position where the effect of the forces is reduced, tension and pressure zones heal and tooth is stabilized in its new position.
In jiggling-type forces The tissue reactions in the periodontal ligament provoked by the combined pressure and tension forces were found to be similar, however, to those reported for the pressure zone at orthodontically moved teeth, with the one difference that the periodontal ligament space at jiggling gradually increased in width on both sides of the tooth. When the effect of the forces applied had been compensated for by the increased width of the periodontal ligament space, the liga- ment tissue showed no signs of increased vascularity or exudation. The tooth was hypermobile but the mobility was no longer progressive in character. Distinction should thus be made between progressive and increased tooth mobility. In jiggling-type trauma experiments, performed on animals with a normal periodontium, the supra- alveolar connective tissue was not influenced by the occlusal force.
Ericsson and Lindhe showed in dog study that within certain limits a healthy periodontium with reduced height has a capacity similar to that of a periodontium with normal height to adapt to altered functional demands.
Lindhe also studied the effect of traumatizing occlusal forces on tissues with plaque associated periodontal disease. Occlusal forces which allow adaptive alterations to develop in the PDL will not aggravate a plaque-associated periodontal disease.
If the magnitude and direction of the jiggling forces were such that, during the course of the study (6 months), the tissues could not become adapted, the injury in the zones of co-destruction had a more permanent character.
Conclusion: Experiments carried out in humans as well as animals showed evidence that trauma from occlusion cannot induce periodontal tissue breakdown. It results though in bone resorption and increased tooth mobility which should be considered a normal adaptation to the increased forces. In teeth with progressive, plaque-associated periodontal disease, trauma from occlusion may enhance the rate of progression of the disease. Clinically this means that the Tx should be directed primarily to the treatment of periodontal disease which will stop the destruction of periodontal tissues even if trauma from occlusions persists. If the Tx is only directed towards trauma from occlusion this may reduce the tooth mobility, but will not stop the further tissue breakdown because of plaque associated periodontal disease.
Should parafunctional habits be managed as part of periodontal therapy ? Does bruxism and/or its management affect the occurrence or prognosis of periodontal disease? What are the symptoms of bruxism? Can periodontal disease be affected by bruxism?
Rugh 1984 ARTICLE
Purpose: To determine whether occlusal discrepancies are sufficient to elicit nocturnal bruxism
Materials and methods:
Nocturnal bruxism was recorded electromyographically (EMG) in humans in whom deflective occlusal contacts were placed .
Ten human subjects without masticatory dysfunction were used to determine whether occlusal discrepancies could trigger nocturnal bruxism.
Full gold veneers were placed on 1st and 2nd molars of either arch. Each was designed to provide 0.5-1mm forward and lateral deflection from CR.
They remained in place for 10-21 nights and then the discrepancy was removed. Nocturnal bruxism was monitored before, during, and after by cumulative recordings of unilateral masseter muscle activity.
Results:
9 of 10 subjects showed a decrease in muscular activity but 4 had other symptoms such as mild TMJ pain or muscle spasm (without increase in nocturnal muscle activity).
BL: Nocturnal bruxism was not elicited by deflective occlusal contacts. It might not be an etiologic factor in nocturnal bruxism
Clarke 1984. NO ARTICLE
Purpose: To monitor nocturnal clenching using a dedicated microprocessor, appropriate EMG amplification and digitisation.
M&M: The real time of bruxing episodes along with the duration and intensity of action was recorded using microcomputer system. Surface electrodes were placed on the temporalis and masseter muscles with a reference electrode on the neck of 10 adult subjects (5F & 5M). 3 maximum clenches (5sec each) made before sleeping & on arousal was compared to the clenching during sleep. Only signals of 2 sec. or > were noted. Data was collected for 7 nights.
Results: No marked differences were observed between the sexes.
The bruxing frequency was inconsistent with bruxing events ranging from 0-17 (widest) to 0-1 (narrowest). Avg= 5. Whereas, bruxing duration episodes were consistent for some and varied for others, 315 sec (widest) on Subject 1, 37 sec (narrowest) on Sub 7. Avg= 7.8 sec. Total bruxing avg. 42 sec. PM clenches were higher than AM clenches. The avg brux was 28% of the avg PM clench and 51% of the avg AM clench. Episodes occurred avg. 5 times for 8 sec.
BL: All subjects were found to brux and two used intensities of effort while asleep that exceeded their max conscious clenches. Study agrees with Nadler (1968) that occurrence of bruxism is universal.
Kydd 1985 ARTICLE
P: To determine: 1) differences in duration of activity of the masseter muscle in bruxers compared with nonbruxers, and 2) effects of an occlusal splint on nocturnal tooth grinding. M&M: The study included 10 pts. with a history of bruxing and 10 nonbruxing controls. All subjects were women 21to 43 years of age. Subjects were tested for 3 nights and then a maxillary occlusal splint was constructed for each bruxing subject. After placement of the splint, the subject was given 2 weeks to accomodate prior to being tested. All subjects were monitored for masseter muscle activity, duration of tooth contacts, heart rate and body movement during 3 nights of testing.
R: Mean duration of masseter activity in the bruxers was 11.4 minutes at night, compared to 3.1 minutes in the controls. This activity most frequently occurred within 15 to 45 minutes of retiring or waking. The duration of bruxing was not significantly altered by the presence of an occlusal splint. However, all subjects reported more comfort while using the splint. Clenchers contracted both masseters simultaneously while bruxers contracted sequentially. Bruxers-clenchers contract the masseter muscles approximately 4x longer than control subjects. All bruxing and nonbruxing subjects demonstrated some nocturnal bruxing activity, although there was great variance.
BL: Occlusal splints did not significantly reduce bruxing/clenching activity.
Hanamura 1987 ARTICLE
P: Analyze the effect of bruxism on periodontal status.
M&M: Two groups: Perio group (51 patients) and bruxism group (40 patients) with minimum 10 occluding teeth, no RP, no fixed prosthesis and no systemic disease. Evaluation: Radiograph: Level of the coronal margin of proximal alveolar bone. Clinically: Number of occluding teeth, mobility (score 0,1,2,3), attachment level, attrition (score 0,1,2,3). Questionnaire: Assess awareness of bruxism in both groups.
R:
1- % of the bone height on root length: 72% perio group, 84% bruxism group.
2- Mean # of occluding teeth: 24,2 perio group, 24,5 bruxism group.
3- Tooth Mobility: More prevalent in perio group (p<0.001).
4- CAL: Attachment loss more pronounced and prevalent in the perio group (p<00.1).
5- Attrition: Severe attrition more frequent in bruxism group.
6- 12 patients of the perio group reported to be aware of clenching and 39 unawareness. NSD in mobility was showed between these subgroups.
BL: Bruxism doesn’t cause deleterious effect on the periodontium.
Discuss buttressing bone
Glickman, Smulow 1965 ARTICLE
P: Discussion article to describe and characterize the formation of "buttressing bone".
D: Description of histological sections cut from 2nd or 3rd molars of two Rhesus monkeys and a mandibular 2nd molar from a human jaw. Buttressing bone is formed as a reinforcement of the bone trabeculae weakened by occlusally induced resorption (OIR). Effects of buttressing bone formation depend on rate and location, the rate of bone resorption induced by excessive occlusal forces, and direction of the forces. Buttressing bone occurs both centrally and peripherally. Centralized formation does not alter gross morphology of the bone. When buttressing bone formation occurs peripherally it can produce bulbous contours in the buccal or lingual plate or a pronounced ridge at the cervical bone margin. If buttressing bone does not keep up with the OIR, an angular bony defect forms next to the root, the bony plate is thinned, and the contour is bulbous. When the OIR greatly exceeds the bone formation, bone height is reduced. Bone is lost due to excessive occlusal forces without destructive inflammation present which can cause or accentuate a dehiscence. Buttressing bone may be stimulated by occlusal forces not great enough to cause trauma from occlusion. It represents an adaptive mechanism to accommodate to altered occlusal forces. Newly formed bone attempts to reinforce trabeculae that are weakened by resorption caused by excessive pressure or require strengthening to accommodate increased occlusal tension. Buttressing bone forms in areas of excessive tension and pressure. The alveolar plate is reshaped in the direction of the tension to try and preserve the normal width of the PDL.
BL: Occlusal trauma can cause angular defects and horizontal bone loss without disease present. Buttressing bone is formed to adapt, strengthen, reinforce, and repair problems caused by excessive forces from occlusion. Consequences of buttressing bone formation are bulbous or ridge-like distortion in the shape of the alveolus and increased radio density in the periodontium.
What are the options for treatment of bruxism?
Ayer 1975 ARTICLE
Massed practice therapy: patient’s nocturnal grinding habits are treated by repeatedly clenching the teeth during the daytime. Past study showed 1 month follow up
P: To describe in greater detail the theoretical model on which massed therapy is based and to update original studies by providing data on the outcome of the treatment 1year follow-up.
D: It is thought that adherence to the program and ultimate success of therapy is more a reflection of personality. Internal personality types (someone who is characterized by feelings and activities directed at having control of the events that occur in life) responds more favorably than external personality types. Massed practice has its foundation in a body of hypotheses collectively known as learning theory and on the formulations of Hull and involves 1) conditioning and/or 2) learning. On the basis of these two theoretical constructs, the individual eliminates a habit by engaging in prolonged massed practice of the undesirable habit. The engaging in the habit then becomes uncomfortable or fatiguing. Its cessation becomes reinforcing so that eventually the habit is eliminated. In the case of parafunctional grinding, patients consciously clenched and relaxed in sessions for two weeks to one year.
BL: Massed practice therapy applied to treat grinding and clenching habits show after one year of therapy elimination of the habit in 75.5% of the 33 patients studied.
Kardachi 1978 ARTICLE
P: To determine the effects of an occlusal adjustment on muscle activity in subjects who brux and to compare these effects to those of biofeedback.
M+M: 20 subjects used, 12 males and 8 females. Two experimental (occlusal adjustment or biofeedback) groups of 4 subjects each and three control groups of 4 subjects each.
Occlusal adjustment group, muscle activity was recorded for 7 nights to establish a baseline of electromyographic (EMG) activity, and then an occlusal adjustment was performed. Biofeedback treatment group, EMG was recorded for 7 days to establish baseline of activity, feedback was applied for 7 days and EMG was recorded for another 7 days. The biofeedback and occlusal adjustment experimental groups were recorded again for several nights after 3 months, to look at long term effects.
Control group with mock occlusal adjustment was performed- nonopposing, nonsupporting tooth surfaces were ground, and EMG activity was measured 7 days before and after this “adjustment.” Untreated control group, diagnosed nonbruxers had EMG activity recorded for 7 nights.
Control feedback group so that effect of application of noise not related to EMG could be assessed.
R:
Occlusal adjustment group: the effects of occlusal adjustment on nocturnal EMG activity varied. In two subjects there was an immediate increase in muscle activity followed by a decrease. In another two subjects there was an initial decrease that returned to baseline levels after 3 months.
Biofeedback group: there was a reduction of approximately 70% in muscle activity that returned to baseline in 3 months.
Mock occlusal adjustment group: there was a slight decrease in muscle activity.
Nonbruxing control group: very little activity was recorded.
Control feedback group: no change was observed
BL: The effects of occlusal adjustment on nocturnal bruxism are unpredictable and short term.
CR: Limits to this study: Stress factor cannot be controlled and there was no method of distinguishing between eccentric bruxism, clenching or other muscle activity during night.
P: To compare effects of hard vs. soft occlusal splints on nocturnal bruxism in the same person
& to provide insight on proper splint selection for treatment of bruxism or bruxism-related disorders.
M&M: 10 healthy subjects (5M/5F) admitting bruxing habits; all have full sets of teeth (except wisdom teeth); average age 27.4 yrs; all splints were fabricated by same operator and to same vertical dimensions (4mm). Study periods were A – B – A – C – A
A: 5 day control period of bruxism monitoring w/ consistent baselines obtained
B: hard splint x 7 days
A: baseline re-establishment for 5 days again
C: soft splint x 7 days
A: no appliance x 5 days
Surface electrodes placed over single masseter muscle monitored mV of activity calculated as mV/hr to the nearest 15 min interval of sleep
R: Hard Splint: 8/10 had sig decrease in m activity; 2/10 there was no sig change.
Soft Splint: 5/10 had sig increase in m activity; 1/10 had sig decrease in muscle activity; 4/10 had no sig change in muscle activity. Furthermore, 4/10 complained of muscle/joint pain and 2/10 complained of muscle tiredness. Of these 6 pts that complained of having new symptoms, 5/6 demonstrated an increase in muscular activity.
BL: This study suggests hard acrylic max splints sig decrease nocturnal muscle activity in the majority of pts & soft splints do not. Moreover, the soft splint is contraindicated with pts that complained of symptoms associated with bruxism.
Purpose: To compare four bruxism trreatments for short- and long-term effectiveness: nocturnal biofeedback , diurnal biofeedback, massive negative practice and splint therapy.
Materials and methods: Subjects were selected based on self reported history of bruxism, they were bruxing recently and someone else had heard them and they had wear facets indicative of bruxism. Significant nocturnal EMG activity was a final criterion. Each participant’s bruxism was monitored during sleeping hours with an electromyographic unit. 20 patients were assigned to each group and 20 in the control group.
Calculation were made for 14 nights of pre-treatment baseline, 14 nights of treatment phase, 14 nights of post-treatment and 14 nights at follow-up six months later.
Nocturnal biofeedback group consisted of an aversive tone sounded in an earphone when the individual bruxed. Patient was requested to arise walk across the room and record the date and time as well as the quality of sleep. Diurnal biofeedback subjects were instructed to use a relaxation tape. Massed negative practice was performed to each of the 20 bruxers in the 3rd treatment group. Six blocks of clenching trials per day consisted of 5 purposefully executed clench/relax cycles. 4th group received splint therapy consisted of the wearing of maxillary flat plane acrylic splint with cuspid rise. No treatment was provided in the control group. 69/100 subjects returned for the 6-month follow-up.
Results: No significant difference between groups at baseline. Both EMG-measured frequency of bruxing episodes and duration of bruxing activity decreased significantly for nocturnal biofeedback and splint therapy treatments but not for massed negative practice, diurnal biofeedback (relaxation), or the no-treatment control group. The 2-week treatment effects were transient, and bruxing activity generally returned to baseline levels when treatment was withdrawn.
Conclusion: Flat-plane occlusal splint and nocturnal aversive biofeedback are both effective treatments for reducing bruxing behavior. Short term interventions are not followed by long-term (6-month) decreases in bruxing activity.
Holmgren 1993 ARTICLE
Purpose: To investigate the effects of the occlusal splint on grinding and clenching during sleep in patients with bruxism and craniomandibular disorders(CMD).
Materials and methods:
31 pts; full-arch maxillary occlusal splint; canine ramps were removed to avoid restricting the mandible during parafunction
Re-examined at 2 week intervals; treatment lasted for 6 months or until total elimination of signs and symptoms.
Results:
Mean increase of vertical dimension: 3.7mm in the incisal area
61% of patients had active wear facets at every visit; 39% observed from time to time; wear facets reappeared in the same location with a similar pattern and direction
In 71% of patients, these facets were created by bilateral mandibular clenching excursions, in 13% of patients, they were created by unilateral excursions, in 3% of patients by protrusive movements
When patients were asked to stop using the splints, 80% of them had recurrence of symptoms within 4 weeks.
BL: Occlusal splints don’t stop habit of nocturnal bruxism. Signs of CMD were reduced with the use of splints. 80% of wear facets created by grinding and reappeared in same location.
Tarantola 1998 ARTICLE
BG: The Glossary of Prosthodontic terms defines an interference as any tooth contact that interferes w/ or hinders harmonious mandibular movement. First, there are occl interferences to the centric relation (CR) arc of closure that cause a displacement of the condyle from its CR posture. Second, there are occlusal interferences on posterior teeth during excursive movements of the mandible. These have shown to cause hyperactivity of the stomatognathic system muscles.
P: Retrospective (pilot) study to determine if occlusal equilibration was an effective way to affect signs & symptoms of masticatory system dysfunction.
M&M: 30 members of the visiting faculty at the Pankey Institute (FL) collected data from their offices that included occlusal equilibration & analyzed signs & symptoms before & after equilibration, using a complete questionnaire sent to their practices. (342 Qs filled out)
R: Avg age: 46 yrs. 73.9% were Female, 29.1% were Male. 74% of pts used bite splints during therapy – 25% did not. Females were prescribed more splints than males. No relationship between age & months of therapy. NSD btwn M/F with respect to the presence or severity of pain. Overall, all signs/symptoms improved after occlusal equilibration. Exceptions in significant changes: no difference in “location of tooth sensitivity” and “location of pain on loading”. All measures of pain improved, location of any residual pain did not change. Pain on loading reported by 59 pts pre-tx & 17 post-tx with no change in the side of pain.
D/BL: Occlusal equilibration can be an effective way to improve signs & symptoms in the stomatognathic system. It should be done only after exam & equilibration of diagnostic casts. Diagnosis of capsular instability should be confirmed first, & if possible, resolved w/ a bite splint first. Stress or systemic-related causes should be identified to better understand the role & effect of equilibration.
Zander 1977 ARTICLE
P: Present the status of occlusion and occlusal therapy in periodontics.
Lesion of trauma from occlusion: a periodontal tissue injury when the occlusal forces acting on a tooth produce displacement of the root in the socket which results in an injury to the supporting PDL.
Primary Traumatic Occlusion: Excessive occlusal force applied to a tooth with normal supporting structures. The changes are reversible when either the force is discontinued or the tooth moves away from the influence of the force. Perio pockets are not formed from traumatic occlusion as the supracrestal fibers remain attached and prevent apical migration of the epithelium.
In the state of increased mobility, actual lesions of trauma are not longer present but rather a widened PDL, which is functionally oriented to accommodate the environmental forces. If the forces are reduced or eliminated the mobility will decrease.
Mobility is a clinical manifestation of the periodontal adaptation to traumatic occlusion. Mobility can occur in the presence of inflammation, trauma or both. The periodontium with continue to remodel in an attempt to accommodate large displacing forces.
Mobility may decrease with resolution of inflammation and may be stable or progressive. If inflammation is resolved, it is possible to have alveolar bone regeneration; however, bone volume can be increased, but in the presence of inflammation vertical bone fill will not occur.
Co-destructive effects between trauma and periodontitis:
Co-destructive relationship: When periodontal trauma occurs subjacent to established marginal periodontitis will result to the progression of existing periodontal pockets, and infra bony pockets with angular bone loss.
The presence of an existing marginal inflammation in the supracrestal connective tissue had inhibited the potential for alveolar bone regeneration. The elimination of such factors will result in a significant and dramatic regeneration of alveolar bone but no coronal gain of CT attachment will occur.
Secondary Traumatic occlusion: Normal occlusal forces causing trauma to the attachment apparatus of a tooth or teeth because of inadequate supporting structure.
Therapeutic Implications:
There is no scientific basis for considering that it is necessary to splint a tooth to adjacent, less mobile teeth in order to preserve periodontal health.
Splinting is indicated only when hypermobility interferes with patient’s comfort and masticatory function or increases to the point of exfoliation.
Berglundh 2005 ARTICLE
P: To study marginal bone level alterations after implant placement, abutment connection and functional loading.
M&M: 6 Beagle dogs. All mandibular premolars were extracted. 3 months later, 4 Astra implants were placed in one side of the mandible, and 4 Nobel implants were placed on the other side and covered. 3 months later abutments were placed and a plaque control regiment was initiated. FPD were placed on the max canines and premolars. FPD was placed in 3 the posterior implants, and the most mesial implant was left not loaded as a control. Radiographs were taken at implant placement, abutment placement, FPD delivery and at 10 month follow-up. Animals were sacrificed at 10 months and histologic evaluation was performed.
Results: Radiographic evaluation showed that the largest amount of bone loss occurred following implant placement and abutment connection and that this loss was more pronounced on Nobel implants than in Astra implants. There was NSD of the bone level during the functional loaded implants vrs the unload implants during the 10 months follow-up. The histologic evaluation revealed that loaded implants exhibited higher degrees of bone-to-implant interface and more bone re-modelling than the unloaded implants.
C: Functional load at implants may enhance osseointegration and does not result in marginal bone loss.
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