Report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry

Occlusal contacts: vectorial analysis of forces transmitted to temporomandibular joint and teeth

Despite relevant command of muscles in the chewing apparatus, occlusion of the upper/lower jaws is constrained by joints and opposing teeth. To describe this system performance, the link quadrilateral bell-crank comprised a suitable model to render vectorial analysis of forces transmitted to the masticatory system during mandibular elevation. Occlusal contacts were created in the above proposed model. No different mechanical responses in the system were found between maximum intercuspation contacts in centric occlusion as compared to long-centric reconstruction. There was a tendency for force decrease in joints and equal force distribution on dentition. Prematurities in centric relation, at least extent, and protrusive interferences produced concentration of forces at dentition and decrease of forces in the joint, while protrusive guidance tended to increase force in the joint.

Predictive value: a model for dentists to evaluate the accuracy of diagnostic tests for temporomandibular disorders as applied to a TMJ scale

The predictive value model for assessing the accuracy of diagnostic test results in the individual patient with a temporomandibular disorder is described. The use of predictive values to help the clinician ascertain the degree of confidence to be placed in diagnostic test results is illustrated. The predictive value model is used to study the accuracy of the TMJ Scale as a diagnostic tool. For all base rates between 0% and 100%, the predictive values of the TMJ Scale result in a gain in accuracy in confirming or excluding a diagnosis of a temporomandibular disorder. The TMJ Scale provides the dentist with improved accuracy of diagnostic decisions regarding the presence of temporomandibular disorders throughout the entire range of base rates found in clinical practice. Application of the predictive value model helps the dentist avoid serious diagnostic errors that could place both the patient and dentist at unnecessary risk.

A dynamic model of etiology in temporomandibular disorders

A dynamic model is proposed to depict the etiology of temporomandibular disorders. A balance is described between destructive factors in the masticatory system that result in dysfunction, and adaptive factors that tend to return it homeostatically to normal. Five factors that cause or potentiate muscle hyperfunction are included on one side of the model with five other factors that affect the ability of the system to adapt on the other side. Relationships among the etiologic factors are discussed, and literature support for each is cited.

Devices for the diagnosis and treatment of temporomandibular disorders. Part I: Introduction, scientific evidence, and jaw tracking

This three-part series of articles summarizes the uses of several devices or groups of devices intended for the diagnosis or treatment of temporomandibular disorders (TMD) and compares their claimed clinical usefulness with the present scientific evidence. Part I of this review defines TMD; discusses the principal criteria for evaluating published scientific clinical evidence such as reliability, validity, sensitivity, and specificity; gives a rationale for the clinical "gold standard" against which diagnostic and therapeutic devices must be compared; and evaluates the status of jaw tracking for the diagnosis of TMD. This review and evaluation led to the conclusion that, at the present time, the claim that jaw-tracking devices have a diagnostic value for TMD is not well supported by the scientific evidence.