Prevalence of dental occlusal variables and intraarticular temporomandibular disorders: molar relationship, lateral guidance, and nonworking side contacts.

STATEMENT OF PROBLEM: The association between dental occlusion and the development of intraarticular temporomandibular disorders remains unclear. PURPOSE: This study evaluated the prevalence of molar relationship, lateral guidance and nonworking side contacts and intraarticular temporomandibular disorders. MATERIAL AND METHODS: Eighty-two asymptomatic volunteers and 263 symptomatic temporomandibular disorder (TMD) patients completed a subjective questionnaire that documented the absence of jaw pain, joint noise, locking, and a positive history for TMD. Participants also underwent clinical and dental examination for signs and symptoms commonly associated with TMD or internal derangements. RESULTS: The most prevalent molar relationship was Class I. Symptomatic patients had a higher prevalence of Class II, Division 1 relationships on the left side compared with the asymptomatic volunteers with normal joints. There was a higher prevalence of canine guidance (52.04%; P <.005) on the right side in the symptomatic patients with disk displacement (DD). Volunteers with normal joints had a higher prevalence of 1 or more nonworking side contacts compared with symptomatic patients with normal joints (P <.001) and symptomatic patients with DD (P <. 001). CONCLUSION: This study suggests there are no systematic dental occlusal differences that clearly separate symptomatic from asymptomatic patients. Results indicate that it is unclear as to the relationship of the 3 analyzed factors and of intraarticular TMDs.

Association between dental occlusal variables and intraarticular temporomandibular joint disorders: horizontal and vertical overlap.

STATEMENT OF PROBLEM: It has been suggested that dental occlusion may play a role in the development of intraarticular temporomandibular joint disorders. PURPOSE: This study evaluated the relationship between horizontal and vertical overlap and intraarticular temporomandibular joint disorders. MATERIAL AND METHODS: Vertical and horizontal overlap of the anterior teeth of 82 asymptomatic volunteers and 263 symptomatic patients were examined. RESULTS: Fifty-five (67%) of the asymptomatic volunteers had normal joints and 27 (33%) had disk displacement. Two hundred and twenty-one patients (84%) had disk displacement and 42 (16%) had bilateral symptomatic normal joints. Horizontal overlap equal to or greater than 4 mm was more prevalent in the symptomatic patient group as compared with the asymptomatic volunteer group (p < 0.05). Vertical overlap equal to or greater than 4 mm demonstrated no significant differences. CONCLUSION: Horizontal overlap equal to or greater than 4 mm was greater in symptomatic patients with intraarticular temporomandibular joint disorders.

The prevalence of disc displacement in symptomatic and asymptomatic volunteers aged 6 to 25 years.

The purpose of this investigation was to determine a possible association between disc displacement and temporomandibular disorders (TMD). Fifty-six Brazilian asymptomatic volunteers (25 males and 31 females) and 181 symptomatic TMD patients (112 females and 69 males) participated. Volunteers did not have temporomandibular joint pain, limited jaw opening, joint sounds, or previous TMD treatment. Bilateral temporomandibular joint magnetic resonance imaging scans were obtained from all subjects. Joints were classified as normal or having disc displacement. Asymptomatic volunteers had 28 (25%) joints with disc displacement; 10 (18%) had unilateral and 9 (16%) had bilateral disc displacement. Of the TMD patients, 25 (13.8%) had bilateral symptomatic but normal joints. Fifty-one (28.2%) had unilateral and 105 (58%) had bilateral disc displacement. Odds ratios (12.2 [95% confidence interval = 6.1 to 24.4, P = .001]) suggest a strong association between disc displacement and TMD. This study suggests that disc displacement is relatively common (34%) in asymptomatic volunteers and is highly associated with patients (86%) with TMD.

Relationship of other joint problems and anterior disc position in symptomatic TMD patients and in asymptomatic volunteers.

Anterior disc position has been highly correlated with temporomandibular disorders (TMD). It was hypothesized that internal derangement of the temporomandibular joint may be a part of a joint phenotype that imparts an increased risk for joint disorders. If this hypothesis is true, an increased prevalence of joint disorders in individuals diagnosed with displaced discs should be expected. A total of 263 symptomatic TMD patients and 82 asymptomatic volunteers was examined. Asymptomatic volunteers with anteriorly displaced discs were twice as likely as asymptomatic volunteers without disc displacements to report pain/dysfunction in other joints. Symptomatic patients with and without displaced discs reported an increase in other joint problems three to four times greater than in asymptomatic subjects. Compared to symptomatic TMD patients without disc displacement, symptomatic TMD patients with anteriorly displaced discs were also twice as likely to report other family members as being affected by TMD. Familial aggregation of TMD and an increased prevalence of other joint problems in these individuals may represent more than a serendipitous occurrence.

Evaluation of the reproducibility of rest activity of the anterior temporal and masseter muscles in asymptomatic and symptomatic temporomandibular subjects.

There is a general assumption that temporomandibular disorders and the pain and tenderness of mastication muscles may be caused by hyperactivity. Five asymptomatic men, five asymptomatic women, and five women with temporomandibular disorders participated in this study. Multiple examinations were performed to provide information concerning the reproducibility of the rest electromyographic signals. No significant differences between groups were noted. This study supports the contention that the mean rest activity in women with pain and dysfunction is less than or equal to that of sex-matched controls.

Rerandomization tests for analyzing correlated data from dental studies.

Dental research studies often produce relatively small data sets in which observations are serially or spatially correlated. Rerandomization tests are presented as alternatives to analysis of variance and multivariate analysis for assessing group differences using such data. Rerandomization tests are particularly useful when the investigator is unwilling to make strong assumptions about the nature of the serial correlation or the distribution of the data. Two examples are discussed that demonstrate these techniques.

Computed tomographic evaluation of the density of the temporomandibular joint meniscus.

Pathologic alteration of the articular disk, including moderate calcification within the meniscus proper, has been reported to occur in many cases of TMJ dysfunction with chronic anterior meniscal displacement. The purpose of this investigation was to measure, by means of direct sagittal computed tomographic scanning technology, the density (x-ray attenuation) of the meniscus. Fifty-two joints, shown to have meniscus displacement with or without reduction (MD/MDR), and 24 symptomatic joints with normal tomograms were evaluated with the use of a GE 8800 CT scanner. Mean attenuation values were extrapolated with the use of a symmetrical (1 to 9 pixels) region-of-interest (ROI) cursor. Density gradients of the masseter muscle, lateral pterygoid fat pad, and lateral pterygoid muscle were also obtained. The results of this study showed that the mean meniscal density values were 116.7 +/- 4.2 Hounsfield units (HU) for MD subjects, 111.3 +/- 4.6 HU for MDR subjects, and 82.4 +/- 2.9 HU for subjects with symptoms. The MD and MDR density group means were significantly different (p less than 0.001) from the normal group means. A relative comparison of the meniscus density with that of the lateral pterygoid muscle, its fat pad, and the masseter muscle showed a consistent mean difference when the paired t test was used. Meniscal displacement was found to be associated with an increase in density gradient, which suggests histologic alteration.

Assessing diagnostic reliability and estimating incidence rates associated with a strictly progressive disease: dental caries.

This paper presents a general approach for simultaneously assessing, from serial data, diagnostic consistency, interrater reliability and incidence of a strictly progressive disease. Observed data are viewed as incomplete: diagnostic errors are not distinguished from true diagnoses. We introduce a broad class of models to separate rater errors from underlying patterns of disease incidence. The analysis can include covariates and risk factors. We provide variance expressions for parameter estimates. Categorical data for estimating the incidence of dental caries serve as an example.