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Few clinical datasets exist in dentistry to conduct secondary research. Hence, a novel dental data repository called BigMouth was developed, which has grown to include 11 academic institutions contributing Electronic Health Record data on over 4.5 million patients. The primary purpose for BigMouth is to serve as a high-quality resource for rapidly conducting oral health-related research. BigMouth allows for assessing the oral health status of a diverse US patient population; provides rationale and evidence for new oral health care delivery modes; and embraces the specific oral health research education mission. A data governance framework that encouraged data sharing while controlling contributed data was initially developed. This transformed over time into a mature framework, including a fee schedule for data requests and allowing access to researchers from noncontributing institutions. Adoption of BigMouth helps to foster new collaborations between clinical, epidemiological, statistical, and informatics experts and provides an additional venue for professional development.

Dental procedures often produce aerosols and spatter, which have the potential to transmit pathogens such as severe acute respiratory syndrome coronavirus 2. The existing literature is limited.Aerosols and spatter were generated from an ultrasonic scaling procedure on a dental manikin and characterized via 2 optical imaging methods: digital inline holography and laser sheet imaging. Capture efficiencies of various aerosol mitigation devices were evaluated and compared.The ultrasonic scaling procedure generated a wide size range of aerosols (up to a few hundred μm) and occasional large spatter, which emit at low velocity (mostly3 m/s). Use of a saliva ejector and high-volume evacuator (HVE) resulted in overall reductions of 63% and 88%, respectively, whereas an extraoral local extractor (ELE) resulted in a reduction of 96% at the nominal design flow setting.The study results showed that the use of ELE or HVE significantly reduced aerosol and spatter emission. The use of HVE generally requires an additional person to assist a dental hygienist, whereas an ELE can be operated hands free when a dental hygienist is performing ultrasonic scaling and other operations.An ELE aids in the reduction of aerosols and spatters during ultrasonic scaling procedures, potentially reducing transmission of oral or respiratory pathogens like severe acute respiratory syndrome coronavirus 2. Position and airflow of the device are important to effective aerosol mitigation.

BackgroundDental procedures often produce aerosols and splatter which have the potential to transmit pathogens such as SARS-CoV-2. The existing literature is limited.MethodsAerosols and splatter were generated from an ultrasonic scaling procedure on a dental mannequin and characterized by two optical imaging methods – digital inline holography (DIH) and laser sheet imaging (LSI). Capture efficiencies of various aerosol mitigation devices were evaluated and compared.ResultsThe ultrasonic scaling procedure generates a wide size range of aerosols up to a few hundred micrometers and occasional large splatter which emit at low velocity (mostly below 3 m/s). Use of a saliva ejector (SE) and high-volume evacuator (HVE) resulted in 63% and 88% of overall reduction respectively while an extraoral local extractor (ELE) resulted in a reduction of 96% at the nominal design flow setting.ConclusionsThe study results showed that the use of ELE or HVE significantly reduced aerosol and splatter emission. The use of HVE generally requires an additional person to assist a hygienist, while an ELE can be operated “hands-free” when a dental hygienist is performing ultrasonic scaling and other operations.Practical ImplicationsAn extraoral local extractor aids in the reduction of aerosols and splatters during ultrasonic scaling procedures, potentially reducing transmission of oral or respiratory pathogens, like SARS-CoV-2. Position and airflow of the device are important to effective aerosol mitigation.

Aims To investigate whether a shortened dental arch (SDA), as identified by reduced posterior occlusal contacts, is a risk factor for the progression of temporomandibular joint (TMJ) intra-articular disorders (ID), as identified using imaging techniques. Methods This multisite, prospective observational study with a mean follow-up period of 7.9 years had a sample of 345 participants with at least 1 temporomandibular disorder (TMD) diagnosis at baseline. SDA was defined as reduced occlusal posterior support due to lack of occlusal intercuspal contacts in the molar region on the left and/or right side. SDA was assessed at baseline and at follow-up with metalized Mylar Tape. The presence or absence of a TMJ ID and the specific TMJ ID diagnoses for baseline and follow-up images were established by a calibrated, blinded radiologist at each of three sites by using bilateral magnetic resonance imaging for soft tissue imaging for disc displacement and by bilateral multidetector computed tomography or cone beam computed tomography for hard tissue imaging for degenerative joint diseases. Wilcoxon rank sum test and linear regression analyses were used to test for an impact of SDA on TMJ ID status. Results At baseline, TMJ ID status of either side was not significantly affected by the presence of SDA on the ipsilateral or contralateral side of the jaw (all P > .05). Furthermore, the presence or absence of SDA at baseline was also not a significant predictor for progression of the TMJ ID status between baseline and follow-up (all P > .05). Conclusion The findings of this study suggest that there is no significant effect of SDA on progression of TMJ ID.

The longitudinal course of temporomandibular joint (TMJ) disc displacement (DD) and degenerative joint disease (DJD) has never been conclusively described with magnetic resonance imaging and computed tomography, respectively. This 8-y observational study’s objective was to assess the longitudinal stability of DD and DJD among 401 subjects. The Validation Project provided baseline measures; follow-up was performed in the TMJ Impact Project. With magnetic resonance imaging, 2 radiologists rendered a consensus diagnosis of normal/indeterminate, DD with reduction, or DD without reduction. Computed tomography consensus diagnoses included normal/indeterminate, grade 1 DJD, or grade 2 DJD. Radiologist reliability was assessed by kappa; a Hui-Walter model was used to estimate, after accounting for diagnostic disagreement, the frequency of diagnostic progression and reversal. Permutation tests were used to test the statistical influence of concurrent baseline diagnoses on diagnostic changes at follow-up. Of 789 baseline joint-specific soft tissue diagnoses of DD, 598 (76%) joints showed no change; 109 (14%) demonstrated progression; and 82 (10%) had reversal. Of 794 joints with baseline joint-specific hard tissue diagnoses of DJD, progression was observed in 122 (15%) joints, no change in 564 (71%), and reversal in 108 (14%). Radiologist reliability (kappa) was 0.73 (95% CI, 0.64 to 0.83) for DD and 0.76 (95% CI, 0.68 to 0.83) for DJD. After accounting for the influence of diagnostic disagreement, progression of hard tissue diagnoses in the right TMJ occurred in 15.2% of subjects (95% CI, 10.5% to 20.8%) and reversal in 8.3% (95% CI, 4.9% to 12.3%); results were similar for soft tissue diagnoses and the left TMJ. Concurrent baseline soft tissue diagnoses were associated with hard tissue diagnostic changes at follow-up ( P < 0.0001). Baseline hard tissue diagnoses showed no statistical association with soft tissue changes at follow-up ( P = 0.11). Longitudinally, 76% of baseline TMJ soft tissue diagnoses and 71% of the baseline hard tissue diagnoses remained stable. Diagnostic reversal and progression were confirmed for both soft and hard tissues.

Many resources and methods are available for dissemination and promotion of the principles and value of evidence-based dentistry among colleagues.

Statement of Problem. Several methods have been used to determine the surface characteristics of resin composites in vivo and compare composite wear rates with enamel wear rates. Purpose. This pilot study describes the surface characteristics of resin composites and the wear of resin composites and enamel during 1 year of in vivo service. Material and Methods. A single Class II posterior resin composite restoration (Z100) was placed in 10 patients. Restored teeth and unrestored adjacent control teeth were measured for wear 4 times within the first year. A null point contact stylus profiler and fitting software were used to measure epoxy casts. Maximum depth of wear, average depth of wear, and characteristics of the restoration margin were determined. Paired t tests were used to compare the control and restored teeth, and ANOVA was used to assess the progression of wear over time ( P Results. After 1 year, maximum depth of wear over the entire preparation region was on average 204.8 μm (± 129.8), significantly greater than the 36.8 μm (± 10.1) average maximum depth of wear of enamel at occlusal contact areas on control teeth ( P =.009). Maximum depth of wear progressed over time ( P =.009). Fracture of excess composite, commonly called flash fracture, occurred in 50% of the restored teeth extending over the preparation margin. Conclusion. Composite restorations wore significantly faster than enamel contact areas on control teeth. Also of concern were the marginal flash fractures that could facilitate secondary caries. (J Prosthet Dent 2000;84:353-9.)

Statement of problem. If masticatory load distribution is task-dependent, then the pattern of wear on an acrylic resin occlusal splint over time may affect clinical outcome. Purpose. This pilot study quantitatively assessed posterior wear after 3 months on the occlusal surfaces of maxillary stabilization splints. Material and methods. Subjects with known history of nocturnal bruxism were given heat-cured full-arch acrylic resin occlusal stabilization splints to be worn nocturnally for 3 months. Splint occlusion was adjusted at appliance delivery and was refined at the baseline session 1 to 2 weeks later. No further adjustment of the splint surface was performed during the 3-month study period. Sequential impressions of the splint occlusal surface provided epoxy resin models that were digitized and analyzed through specialized software. Changes in the digitized splint surface from baseline to 3 months allowed comparison of wear facets between splint sides and among tooth locations. Results. Splint wear was asymmetric between sides and uneven between dental locations. Conclusions. For full coverage occlusal splints, the appliance wear phenomenon can be site specific and, if left undisturbed, may yield two extremes of high wear and a zone of low wear in-between. (J Prosthet Dent 1998;80:209-13.)

Statement of problem. Although all the processes of loss of hard tissue are important, attrition on the occlusal surfaces commands our attention. Purpose of study. The enamel wear rate of 18 young adults over 2 consecutive years was measured independently by volume loss and mean depth loss. Any significant differences in tooth wear resulting from gender and a clinical diagnosis of bruxism were identified. Material and methods. A strict protocol for dental impressions provided epoxy models, which were digitized with a null point contact stylus. AnSur software provided a complete morphologic description of changes in the wear facets. Results. The mean loss for all teeth measured was 0.04 mm 3 by volume and 10.7 μm by depth for the first year. Conclusions. These numbers were approximately doubled at 2 years of cumulative wear. (J Prosthet Dent 1997;77:313-20.)

This study tested a jaw support device for patients receiving dental care while suffering from temporomandibular joint pain. This crossover randomized trial used 31 subjects with jaw pain. Subjects underwent 2 consecutive dental scaling sessions of 30 minutes each. For each subject, the device was used for 1 of the sessions. Subjects completed questionnaires regarding jaw pain and jaw fatigue before and after each session. Multivariate analyses were performed to assess the device's effectiveness in preventing the aggravation of pain and fatigue during dental treatment. Statistically significant differences were found for jaw pain (P = 0.001), and fatigue (P = 0.04), indicating the effectiveness of the device. Based on the results, supporting the mandible of patients with temporomandibular disorders during dental treatments may prevent further pain.

Aims: We assessed and compared the diagnostic accuracy of two sets of diagnostic criteria for headache secondary to temporomandibular disorders (TMD). Methods: In 373 headache subjects with TMD, a TMD headache reference standard was defined as: self-reported temple headache, consensus diagnosis of painful TMD and replication of the temple headache using TMD-based provocation tests. Revised diagnostic criteria for Headache attributed to TMD were selected using the RPART (recursive partitioning and regression trees) procedure, and refined in half of the data set. Using the remaining half of the data, the diagnostic accuracy of the revised criteria was compared to that of the International Headache Society’s International Classification of Headache Diseases (ICHD)-II criteria A to C for Headache or facial pain attributed to temporomandibular joint (TMJ) disorder. Results: Relative to the TMD headache reference standard, ICHD-II criteria showed sensitivity of 84% and specificity of 33%. The revised criteria for Headache attributed to TMD had sensitivity of 89% with improved specificity of 87% ( p Conclusion: Having significantly better specificity than the ICHD-II criteria A to C, the revised criteria are recommended to diagnose headache secondary to TMD.

Treacher Collins syndrome (TCS) is a common genetic disorder with high penetrance and phenotypic variability. First and second branchial arches are affected in TCS, resulting in craniofacial and intraoral anomalies such as: severe convex facial profile; mid-face hypoplasia; microtia; eyelid colobomas; mandibular retrognathism; cleft palate; dental hypoplasia; heterotopic teeth; maxillary transverse hypoplasia; anterior open bite; and Angle Class II molar relationship. A high incidence of caries is also a typical finding in TCS patients. Nonetheless, even simple dental restorative procedures can be challenging in this patient population due to other associated medical conditions, such as: congenital heart defects; decreased oropharyngeal airways; hearing loss; and anxiety toward treatment. These patients often require a multidisciplinary treatment approach, including: audiology; speech and language pathology; otorhinolaryngology; general dentistry; orthodontics; oral and maxillofacial surgery; and plastic and reconstructive surgeries to improve facial appearance. This paper's purpose was to present a current understanding of Treacher Collins syndrome etiology, phenotype, and current treatment approaches.

The primary aim was to determine new estimates for the measurement reliability of the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) Axis I diagnostic algorithms. A second aim was to present data on the reliability of key clinical measures of the diagnostic algorithms.Kappa (k), computed by generalized estimate equation procedures, was selected as the primary estimate of interexaminer reliability. Intersite reliability of six examiners from three study sites was assessed annually over the 5-year period of the RDC/TMD Validation Project. Intrasite reliability was monitored throughout the validation study by comparing RDC/TMD data collections performed on the same day by the test examiner and a criterion examiner.Intersite calibrations included a total of 180 subjects. Intersite reliability of RDC/TMD diagnoses was excellent (k0.75) when myofascial pain diagnoses (Ia or Ib) were grouped. Good reliability was observed for discrete myofascial pain diagnoses Ia (k = 0.62) and Ib (k = 0.58), for disc displacement with reduction (k = 0.63), disc displacement without reduction with limited opening (k = 0.62), arthralgia (k = 0.55), and when joint pain (IIIa or IIIb) was grouped (k = 0.59). Reliability of less frequently observed diagnoses such as disc displacements without reduction without limited opening, and osteoarthrosis (IIIb, IIIc), was poor to marginally fair (k = 0.31-0.43). Intrasite monitoring results (n = 705) approximated intersite reliability estimates. The greatest difference in paired estimates was 0.18 (IIc).Reliability of the RDC/TMD protocol was good to excellent for myofascial pain, arthralgia, disc displacement with reduction, and disc displacement without reduction with limited opening. Reliability was poor to marginally fair for disc displacement without reduction without limited opening and osteoarthrosis.

Occlusal load, contact sequence and location are necessary parameters for the study of dental biomechanics, simulation and clinical treatment planning. A piezoelectric film transducer for dental occlusal analysis was developed and in vitro evaluations of the transducer were conducted in a servohydraulically driven artificial mouth. The transducer is designed to provide occlusal contact force information. The transducer thickness (9 mum) minimizes interference with normal mandibular closure. Voltage outputs from the sensor as a result of occlusal contacts generated in the artificial mouth were sampled through a computer controlled data acquisition system. The transducer output recorded by the data acquisition system was calibrated to the applied load in the artificial mouth. The output of the piezoelectric film was evaluated during varying loads, cycling frequencies, surface areas of contact, and transducer surface areas. The preliminary studies indicate that the piezoelectric film holds out considerable promise and with further development may be well suited as a diagnostic tool in dental occlusal analysis.

Statement of Problem. Quantitative measures of occlusal contacts are of paramount importance in the study of chewing dysfunction. A tool is needed to identify and quantify occlusal parameters without occlusal interference caused by the technique of analysis. Purpose. This laboratory simulation study compared occlusal contacts constructed from 3-dimensional images of dental casts and interocclusal records with contacts found by use of conventional methods. Material and Methods. Dental casts of 10 completely dentate adults were mounted in a semi-adjustable Denar articulator. Maximum intercuspal contacts were marked on the casts using red film. Intercuspal records made with an experimental vinyl polysiloxane impression material recorded maximum intercuspation. Three-dimensional virtual models of the casts and interocclusal records were made using custom software and an optical scanner. Contacts were calculated between virtual casts aligned manually (CM), aligned with interocclusal records scanned seated on the mandibular casts (C1) or scanned independently (C2), and directly from virtual interocclusal records (IR). Sensitivity and specificity calculations used the marked contacts as the standard. Contact parameters were compared between method pairs. Statistical comparisons used analysis of variance and the Tukey-Kramer post hoc test ( P = Results. Sensitivities (range 0.76-0.89) did not differ significantly among the 4 methods ( P =.14); however, specificities (range 0.89-0.98) were significantly lower for IR ( P =.0001). Contact parameters of methods CM, C1, and C2 differed significantly from those of method IR ( P CM/C1 = CM/C2 > C2/IR > CM/IR > C1/IR, where ">" means "closer than." Conclusion. Within the limits of this study, occlusal contacts calculated from aligned virtual casts accurately reproduce articulator contacts. (J Prosthet Dent 2002;88:622-30.)

Purpose The purpose of this study was to develop an approach to the measurement of occlusal contact area and location using digitized video images of occlusal records. Materials and Methods Five occlusal records in the intercuspal position were made using a polyvinylsiloxane material on five subjects with intact, natural dentition. In regions of occlusal contact, the material showed a minimal film thickness without perforation. A dental cast of the mandibular arch was video digitized and followed by digitization of each of the five occlusal records in place on the cast. An impression of a calibration stepwedge was video digitized to provide the relationship between impression material thickness and pixel density. Results Contact surface areas ranged from 0.02 to 3.16 mm2 between subjects. The contact positions on a single tooth determined in five records from a single individual showed coefficients of variation between 7.4% to 36.1%. Large variations in contact size were found in this group of five records from a single individual (coefficient of variation ranged from 10.8% to 156.7%). The large difference in contact size between records may be due to variations in biting force at the time the records were made. When the cast position was changed and records redigitized, the mean area of the contact was not significantly different (P > .20) from measurements at the original position. Conclusions For the small sample evaluated, a large variation in occlusal contact size was found in the five records. The occlusal contact location was consistent in the five records. The measurement method developed seems to provide reliable measures of occlusal contact surface area and location.

The submental-vertical (S-V) radiograph has become popular in the assessment of craniofacial asymmetry because of ease in identifying reliable midline reference structures. To date, no standards of asymmetry that use the S-V projection have been reported. Submental-vertical radiographs were obtained on 44 adults. Subjects were excluded if previous orthodontic treatment or temporomandibular joint symptoms were reported. With the use of a system of asymmetry analysis developed by Ritucci and Burstone, asymmetry was reported for cranial base, zygomaxillary complex, and mandibular structures. Mean and standard deviations were used to report the asymmetry values across 23 pairs of anatomic landmarks. The data showed that asymmetry is present to some degree in all landmarks and patients. Further, strong asymmetry associations existed between landmarks within patients, with most high positive correlation coefficient values found between regionally or geometrically related points. A refined version of the asymmetric analysis was presented that included easily identified and clinically relevant points. This system is more feasible for the orthodontic clinician.

Reliability of clinical measurement is essential to any clinical discipline. This investigation assessed intraexaminer and interexaminer reliability achieved in identifying contacting teeth in the intercuspal position. Shim stock and an articulating film were compared in the evaluation of occlusal contacts of 337 antagonist occlusal pairs in 24 young adults by two examiners. Results were compared by use of a simple proportion of agreement and, when possible, the Kappa statistical test that corrects for chance agreement. Shim stock displayed better reliability than articulating film and appeared suitable for clinical measurement of occlusal contacts in intercuspal position.

Temporomandibular joint internal derangement (TMJ ID) is the most common intra-articular TM disorder and can progress from TMJ ID with reduction to TMJ ID without reduction. It is not known whether this anatomical progression is associated with increasing levels of mandibular dysfunction. The objective of this study was to determine whether the level of clinically detectable mandibular dysfunction was related to the stage of TMJ ID. Two clinicians examined 42 subjects prior to bilateral TMJ arthrographic evaluation. The level of mandibular dysfunction was calculated by Helkimo's Clinical Dysfunction Index (Di) and the Craniomandibular Index (CMI). Statistical analysis revealed that the level of mandibular dysfunction as determined by the Di and CMI was not related to the arthrographic presence or absence of TMJ ID. Therefore, the clinician cannot assume that the level of mandibular dysfunction is directly related to the absence or presence of TMJ ID. Epidemiologically, the CMI and Di can be used only for estimation of the degree of mandibular dysfunction, since they do not provide direct information on a specific TM disorder.

Internal derangements of the temporomandibular joint (TMJ) have gained increased recognition as a potential source of pain and dysfunction of the masticatory system. The objective of this study was to evaluate the reliability of clinicians in predicting an arthrographic diagnosis of articular disc position in a typical patient population presenting for TMJ arthrographic evaluation. Two clinicians utilized a brief history, clinical examination (including evaluation of mandibular movement and TMJ auscultation), and tomographic TMJ imaging in evaluating 60 patients. The radiologist subsequently performed the arthrographic procedures on 102 TMJs (18 unilateral and 42 bilateral). Diagnostic agreement was determined for all possible diagnostic categories including: normal disc position, TMJ internal derangement with reduction, TMJ internal derangement without reduction/acute, TMJ internal derangement without reductionlchronic, and osteoarthrosis. The significance of the diagnostic agreement between the clinicians and arthrography was evaluated with a Kappa Statistical Test, which showed good reliability. For epidemiological studies, it was concluded that clinical and tomographic evaluation would provide sufficient reliability for determination of the presence and stage of TMJ internal derangement. However, in a specific clinical situation, a difficult diagnostic problem may require the use of arthrography, depending on the impact of the diagnosis on subsequent treatment decisions.

Epidemiological investigations about the prevalence of TMJ ID and osteoarthritis have largely reported the symptoms and signs associated with these disorders without specific criteria to establish the diagnosis. In this study, specific diagnostic criteria have been developed, using historical, clinical and tomographic items that are predictive of the presence and stage of TMJ internal derangement. The diagnostic criteria were compared to arthrotomography to assess their diagnostic accuracy. Overall, the percent agreement was 75%. The predictability of specific stages of TMJ ID varied. Overall, sensitivity and specificity of the criteria were acceptable. The diagnosis of osteoarthritis was predicted only with tomography. Utilization of these diagnostic criteria in epidemiological studies is valid due to their high overall predictiveness when applied to a large population.

The movement of the mesiolingual cusp of the maxillary left first molar was studied in the frontal and horizontal planes. The movement was studied while varying the top wall, rear wall, and incisal guidance on the articulator. It can be concluded that the top wall inclination may significantly influence movement of the mesisolingual cusp of the maxillary first molar during working mandibular movement, the rear wall inclination has less influence than top wall inclination on cusp movement during a working mandibular movement, and the working side condylar movement should be considered when evaluating or restoring the dentition.

C omplete denture fabrication is fraught with both extrinsic and intrinsic potential error. The greater part of this error can be controlled with careful clinical and laboratory technique. ’ Woelfel and Paffenbarge9 outlined the inaccuracies inherent to the use of poly(methy1 methacrylate) as a denture base material. Dimensional change during processing is one such source of error. The processing shrinkage of poly(methy1 methacrylate) resin is well documented.*” Injection processing of poly(methy1 methacrylate) denture bases was introduced by Pryor in an attempt to reduce processing shrinkage. More recently a continuous-pressure injection technique has been developed (SR-Ivocap, Ivoclar AG, Schaan, Liechtenstein). As discussed by Schmidt9 the process claims to deliver reduced processing error and increased resin density through layered curing of the resin and no processing flash. Trituration of the liquidpowder system is mechanically performed in prepackaged capsules in an attempt to produce a more even mix resulting in a homogeneous denture base. The mixed resin is injected into the flask under continuous pressure during the processing.” This study determined the dimensional changes of heat-cured poly(methy1 methacrylate) resin processed by the injection processing system compared with that processed by a conventional compression packing technique.

Kittens, dutch-belted rabbits, and albino rabbits were tested daily after eye opening for development of a reliable avoidance response on the visual cliff under varying conditions of texture density of elements comprising the checkerboard patterns of deep and shallow surfaces. Depth avoidance was demonstrated at an earlier age when coarse (34° to 18° retinal angle) rather than fine (2° or less of retinal angle) elements comprising shallow and deep surfaces were available to the subject. Visually guided placing to surfaces (in cats) developed after onset of visual cliff depth avoidance when coarse texture elements, but not when fine texture elements were used. Differences in onset of depth-avoidance responding under different conditions of texture density across species as well as non-coincidence of onset of visual placing with depth avoidance in cats indicated that changes in texture-processing abilities with age and as a function of species characteristics interact with developing visual-motor responding. The results were interpreted relative to organismic development of texture-processing systems affecting degree of degradation of primary visual input during development. The importance of texture-derived afferent information on development of visual-motor behaviors was discussed.

patient is asked to bite together. The high spots are marked, as are the areas that bind the gauge from pulling through freely. The tooth is then reduced appropriately on the marked areas. If the gauge doesn’t pull through, the process is repeated: marking with articulating paper, grinding, and checking for clearance. The process is repeated as often as necessary until the gauge pulls through, which indicates the desired reduction. If it is inconvenient to customize and store blotting paper, a rubber band may be substituted. The common variety used by the U.S. Postal Service to bind a packet of letters is suitable. The rubber band measures about %6 inch thick (1.1 mm), % inch wide, and 3 inches long. The rubber band may be cut to a length of twice the width of the occlusal marking paper. One advantage is that the rubber band can be sterilized and used repeatedly. The flexibility of a rubber band to ride over cusps is undeniable.

Orthopedic mandibular repositioning and flat plane occlusal splint therapy were compared in the treatment of 20 patients with internal TMJ derangement with reduction. The following conclusions can be drawn. Mandibular repositioning treatment produces significant subjective and objective improvement in the dysfunction of patients with internal joint derangements with reduction. Flat plane occlusal splint treatment produces no significant change in the dysfunction level of patients with internal joint derangements with reduction. Mandibular repositioning treatment may eliminate the reciprocal click of internal joint derangement with reduction. To realize improvement in dysfunction of internal joint derangement, it appears that the reciprocal click must be eliminated. Mandibular repositioning treatment produces a significant improvement in muscle pain associated with internal joint derangement.

Simulated occlusal wear utilizing the artifical mouth included natural enamel against isosit and polymethyl methacrylate splint materials. The results reported in volume loss (mm 3 ) demonstrated the isosit material to be 55–67% more resistant to wear than polymethyl methacrylate. No wear occurred on the enamel surface opposing either splint material.