Andrew G. Pullinger

A Multiple Logistic Regression Analysis of the Risk and Relative Odds of Temporomandibular Disorders as a Function of Common Occlusal Features

A multiple logistic regression analysis was used to compute the odds ratios for 11 common occlusal features for asymptomatic controls (n = 147) us. five temporomandibular disorder groups: Disc Displacement with Reduction (n = 81), Disc Displacement without Reduction (n = 48), Osteoarthrosis with Disc Displacement History (n = 75), Primary Osteoarthrosis (n = 85), and Myalgia Only (n = 124). Features that did not contribute included: retruded contact position (RCP) to intercuspal position (ICP) occlusal slides < 2 mm, slide asymmetry, unilateral RCP contacts, deep overbite, minimal overjet, dental midline discrepancies, ≤ 4 missing teeth, and maxillo-mandibular first molar relationship or cross-arch asymmetry. Groupings of a minimum of two to at most five occlusal variables contributed to the TMD patient groups. Significant increases in risk occurred selectively with anterior open bite (p < 0.01), unilateral maxillary lingual crossbite (p < 0.05 to p < 0.01), overjets > 6-7 mm (p < 0.05 to p < 0.01), ≥5-6 missing posterior teeth (p < 0.05 to p < 0.01), and RCP-ICP slides > 2 mm (p < 0.05 to p < 0.01). While the contribution of occlusion to the disease groups was not zero, most of the variation in each disease population was not explained by occlusal parameters. Thus, occlusion cannot be considered the unique or dominant factor in defining TMD populations. Certain features such as anterior open bite in osteoarthrosis patients were considered to be a consequence of rather than etiological factors for the disorder.

Quantification and validation of predictive values of occlusal variables in temporomandibular disorders using a multifactorial analysis.

STATEMENT OF PROBLEM A consensus is lacking on the association between occlusal variables and temporomandibular disorders (TMDs). PURPOSE This study estimated the maximum potential power of occlusal variables to differentiate patients with TMD from asymptomatic normal adult subjects. MATERIAL AND METHODS The occlusal characteristics in 2 sets of female patients with intracapsular TMD (1993, n = 257, and 1998, n = 124) differentiated into disk displacement and osteoarthrosis subdiagnoses were compared with asymptomatic female controls (n = 51 and 47) with multiple logistic regression analysis. Significant variables and total contribution to the log likelihood were compared with the predictive value of univariate analysis, including sensitivity and specificity. RESULTS Occlusal factors in the females (1993, 1998) explained no more than 4.8% to 27.1% of the log likelihood. In comparison to the logistic regression analysis, univariate analysis was less predictive of patients with TMD, due to notably lower sensitivity. Patients with disk displacement were mainly characterized by unilateral posterior crossbite and longer RCP-ICP slides. Patients with osteoarthrosis were most consistently characterized by longer RCP-ICP slides and larger overjet, and in part to reduced overbite. Significant relative risk for disease (odds ratio > 2:1) was mainly associated with infrequent, more extreme ranges of occlusion measurements. CONCLUSION Occlusal factors may be cofactors in the identification of patients with TMD, but their role should not be overstated. Some occlusal variation may be a consequence of rather than a cause for TMD. Single variables have more limited value and it takes sets of adverse variables to model TMD. Combinations of variables appear to be disease specific. Some extreme ranges of occlusion were the domain of patients with TMD, but most patients were within the normal ranges.

The Prevalence of Dental Attrition and its Association with Factors of Age, Gender, Occlusion, and TMJ Symptomatology

Dental attrition severity in 222 young adults was assessed from dental casts as the sum of the most severe facet in each arch segment. The attrition scores were compared by age, gender, bruxism awareness, prior bite adjustment, orthodontic class, maxillomandibular relationship, and temporomandibular dysfunction symptoms. Awareness of bruxism was not associated with the wear scores and should not be used to define bruxist groups. Attrition scores did not differ significantly between age groups, indicating that notable attrition, when present, often occurs early. Men had higher attrition scores than women (p<0.01), despite fewer signs and symptoms. Dental attrition was not associated with the presence or absence of TMJ clicking, TMJ tenderness, or masticatory muscle tenderness. Class II division 2 males had laterotrusive attrition scores lower than those of Class III (p<0.05). Class III females had lower incisor attrition scores than did other Angle Classes (p<0.05). Discernible dental attrition in a non-patient population was not associated with signs and symptoms of temporomandibular disorders, nor with the occlusal factors studied. These results are compatible with the findings in other studies that point to bruxism as a centrally induced phenomenon common to all people and unrelated to local factors.

Relationship of mandibular condylar position to dental occlusion factors in an asymptomatic population.

This article investigates the influence of occlusion on condylar position as seen on TMJ tomograms in a group of 44 young adults with no histories of orthodontic or occlusal therapy and no objective signs of masticatory dysfunction; the sample was screened from a population of 253 students. Nonconcentric condylar position at ICP was a feature of Class II malocclusion with significantly more anterior positions in Class II, Division 1 than in Class I. Condylar position was unrelated to the amount of sagittal RCP-ICP slide, although most slides were less than 0.5 mm. The frequency of lateral slides was low, but was mildly related to bilaterally asymmetric condylar positions. Position was unrelated to the degree of overbite, which ranged from 0 to 10 mm. Bilateral condylar position asymmetry was not related to the direction of dental midline discrepancy, which ranged from 0 to 2 mm. No open bites or mandibular overjets were seen in this asymptomatic normal sample.

Temporomandibular disorders. Part II: Occlusal factors associated with temporomandibular joint tenderness and dysfunction.

Two complete classes of freshman dental and dental hygiene students, 120 men and 102 women (mean age 23.9 years) were assessed for the presence of masticatory pain or dysfunction by questionnaire, clinical examination, and evaluation of dental casts according to strict criteria. The purpose was to identify the degree of association between observable signs of TMJ disorders and selected combinations of occlusal variables. TMJ tenderness was more frequent in class II, division 2 than in class I (p less than .05), but overall was not associated with occlusal factors such as deep overbites, length of a symmetric RCP-ICP slide, and unilateral contact in RCP. Overall, clicking was not associated with Angle class, deep overbite, length of symmetric RCP-ICP slide, or unilateral RCP contact. Among subjects with unilateral RCP contact, those with no clinically obvious RCP-ICP slide (p less than .005) and those with asymmetric slides (p less than .05) had more TMJ clicking than subjects with symmetric slides. Luxation clicking of the condyle over the articular eminence on wide opening was absent in class II, division 2 subjects, but was most frequent in subjects with some teeth in unilateral posterior crossbite, particularly when this was a unilateral condition (p less than .001). Certain occlusomorphologic conditions may require less adaptation in the TMJs. This article indicates that an ICP anterior to the RCP in association with bilateral occlusal stability may be protective.

Temporomandibular disorders. Part I: Functional status, dentomorphologic features, and sex differences in a nonpatient population

Freshman dental and dental hygiene students, 120 men and 102 women (mean age 23.9 years), were assessed for the presence of masticatory pain or dysfunction by questionnaire, clinical examination, and evaluation of dental casts according to strict criteria. The purpose was to identify and analyze the level of signs and symptoms in a nonpatient population and describe occlusal variation. The prevalence of TMJ signs and symptoms was notable even though two thirds reported only mild or early symptoms, with only 3% reporting severe symptoms. This population was noted for the absence of locking, the low frequency of severe pain or severe TMJ dysfunction, and the low prevalence of restricted ranges of mandibular movement and TMJ crepitation. Women showed significantly more headache, TMJ clicking and tenderness, and muscle tenderness than men. Men were noted for the absence of severe and widespread muscle tenderness and severe TMJ tenderness. TMJ clicking was not always clinically confirmable in subjects with widespread muscle tenderness. This group was considered compatible with previous epidemiologic findings, and also matches the age range of most subjects seeking treatment for TMJ disorders. Therefore, the subjects in the study were considered a representative group of young adults and suitable for study of the possible associations between early signs of TMJ disorders and variables of morphologic malocclusion, which are discussed in Parts II and III of this article.

Variation in condyle-fossa relationships according to different methods of evaluation in tomograms

Mandibular orthopedic diagnosis is frequently based on observation of radiographic nonconcentric condyle-fossa relationships, but the definition of normal and abnormal positions is, in part, obscured by the several different methods used to assess condyle position and the absence of intermethod comparisons. This study compared the measurement and expression of condyle position in tomograms according to subjective evaluations and linear and area measurement of the interarticular space by use of a microcomputer and graphics tablet. Area analysis showed the least concordance with the subjective evaluation. Linear measurement of the subjective closest anterior and posterior interarticular space presented the greatest concordance, had low interobserver variation, and was considered clinically relevant to the functional thickness of the center of the articular disk.

Trauma history in diagnostic groups of temporomandibular disorders

Trauma history was studied for association with disease among six diagnostic subgroups of 230 patients with temporomandibular disorder (TMD) from a private practice setting with (1) disk displacement (DD) with reduction, (2) DD without reduction, (3) osteoarthrosis (OA) with prior derangement history, (4) primary OA, (5) myalgia only, and (6) subluxation only. Except for subluxation (29%), trauma history typified TMD patient groups 1 to 5 (63%, 79%, 44%, 53%, 54%) (p less than 0.001) compared with 13% and 18% of asymptomatic (n = 61) and symptomatic (n = 161) student control subjects, and 11% of general dental patients (n = 150). TMD groups 2 and 3 differed significantly (p less than 0.05). The high prevalence of trauma in the myalgia-only group complicates the concept of myofascial pain-dysfunction syndrome as solely a stress or centrally mediated disorder. DD without reduction (43%) and with reduction (38%) had the highest prevalences of motor vehicle accident trauma, myalgia and OA groups had less, and subluxation-only cases had none. On the other hand, patients with DD without reduction were also the only group to report multiple trauma (29%), suggesting that although specific traumatic events may seem to precipitate clinical symptoms, they may not always have initiated the problem. Trauma may be both an important cumulative and precipitating event in TMDs.

Assessment of mandibular condyle position: A comparison of transcranial radiographs and linear tomograms

Transcranial radiographs are frequently used to assess condyle-fossa relationships. However, their validity in representing condyle position has been questioned. Intermethod comparisons were performed between methods assessing condyle position by subjective evaluation and by linear and area measurement of the interarticular space. Linear measurement of the subjective closest anterior and posterior interarticular space and subjective evaluation were the mutually preferred methods in both transcranial radiographs and tomograms. Statistically significant correlations were shown (p less than 0.05) for condyle position between pairs of clinical transcranial radiographs and linear tomograms of the same temporomandibular joints. However there was a qualitative concordance in assessed posterior concentric and anterior positions in only 80% of the pairs, and a full concordance in the degree of condylar displacement was found in only 60% of the cases. Although still clinically helpful, the use of transcranial radiographs to monitor small changes in condylar position relative to the tomogram was questioned.

Relationship of TMJ Articular Soft Tissue to Underlying Bone in Young Adult Condyles

This investigation used a histological model to study the relationship of articular soft-tissue thickness and contour to the underlying bone in the TMJ condyle of young adults. The usefulness of selected dental and demographic factors in the prediction of the articular soft-tissue thickness and contour was also tested. One sagittal histological section was studied from the lateral, central, and medial thirds of 53 left mandibular condyles. Outline tracings of the articular and compact bone surface were divided into anterior, superior, and posterior sectors for the study of curvature measured by the overlaying of a template of a harmonic series of arcs. The thickness and composition of the articular tissues were measured in each sector by light microscopy. The fibrous connective tissue layer always maintained the articular surface, even in the absence of a cartilage layer. The histological character, including the presence or absence of cartilage, rather than the overall tissue thickness, was considered to be a more useful marker of functionally stimulated changes in the joint. Articular soft-tissue thickness was not related to surface deviation in form and was not correlated with age in this young adult sample. Reduced soft-tissue thickness in the anterior part of the condyle was more common in cases with lack of molar support. Dental attrition was not a useful predictor of soft-tissue thickness. Compact bone contour correlated with soft-tissue contour in the superior (r = 0.816) and posterior (r = 0.808) sectors, explaining only 64% of the variance, but not in the anterior sector (r = 0.265). Thicker or thinner articular soft tissue was not predictable by the underlying compact bone contour or thickness. Therefore, the clinician should not automatically assume that the radiographic osseous image represents the actual articular surface.