J.A. Clayton

Effects of occlusal splint therapy on TMJ dysfunction

A study was conducted to ascertain what happens to dysfunction symptoms followed only by occlusal splint therapy. Four hundred eighty-six pantograms were made on 15 experimental patients over a period of 5 months to 1 year. Five control patients were monitored over this same period but received no occlusal therapy. The experimental patients with TMJ dysfunction were treated with occlusal splint therapy. The occlusal splints were worn until the dysfunction symptoms were reduced and the pantographic PRI scores were reproducible. The occlusal splints were than removed without occlusal adjustments and the patients were monitored pantographically. A statistical analysis was performed on the PRI scores to determine the relationship between experimental and control patients. Experimental patients had an average drop of 21.7 points during occlusal splint therapy as compared to 3.8 points for control patients. All experimental patients had an increase in the PRI score levels following the removal of the occlusal splints.

A measurement of clasp forces on teeth

Abstract A method that measures the force which clasps transmit to abutment teeth was developed and a comparative study was made between the effectiveness of a wrought wire clasp and that of a cast bar clasp. A transducer, using a resistance strain gauge, measured the flexure of clasps and the forces exerted by the clasps on abutment teeth. The cast bar clasps were more flexible than the wrought wire clasps of equal length. All of the clasps tested exerted forces against the teeth when the removable partial denture bases were at rest. The wrought wire clasps flexed a greater distance and exerted more force against the abutment teeth when the casting was seated and removed from the model. The forces exerted by the clasps when the casting bases were moved were different from each other and yet followed a pattern. The force increased for both types of clasps as the bases were depressed; however, the wrought wire clasp exerted more force than the cast bar clasps. The forces measured could be significant when the direction and the result of the forces were examined. The wrought wire clasps may tilt the abutment tooth distolingually and the cast bar clasp may force the tooth mesiolingually. The results of this study question some of the empirical theories used today to substantiate extension partial denture clasp designs. It appears that the theoretical and the practical do not always agree; therefore, the theoretical should be tested further.

Using pantographic tracings to detect TMJ and muscle dysfunctions

Forty-six subjects were examined using the HDI and a PRI. Two sets of pantographic tracings were used to determine if subjects experiencing dysfunction could differentiate between degrees of dysfunction. Subjects were divided into groups according to their clinical symptoms: none (D0), sligh (D1), and moderate dysfunction (D5). Each subject was further classified into one of two groups according to his state of occlusion/articulation. The PRI detected differences between the group with moderate dysfunction and those groups with no dysfunction and slight dysfunction on the basis of differences between the first and second sets of tracings; no difference was found between the groups with slight and moderate dysfunction. Subjects with poor occlusions had higher PRI scores. The diagnosis of TMJ dysfunction may require the use of several modalities such as subjective responses, clinical examination, radiographs, and pantographic tracings.

Effects of occlusal therapy on pantographic reproducibility of mandibular border movements

A clinical experiment was undertaken to study the relationship between occlusal therapy and pantographic reproducibility. Twenty-six subjects were categorized according to their ability to reproduce pantographic border movements and were put into either a control nonreproducible, control reproducible, or experimental nonreproducible group. From each subject a sequence of five pantographic surveys consisting of two morning and two afternoon pantographic recordings was taken. Each survey period lasted a minimum of 30 days. The experimental subjects alone were given occlusal splint therapy and occlusal adjustment therapy during the sequence of recall periods. The relationship between the effect caused by occlusal therapy and pantographic reproducibility was analyzed. For the purpose of analysis, the pantographic recordings were assessed a numerical score using a pantographic reproducibility index. A double-blind technique was used until all data were collected.

Graphic recordings of mandibular movements: Research criteria

Abstract Studies using graphic tracing devices have yielded conflicting results concerning mandibular movements. The purpose of this study was to determine whether graphic tracings could be affected by styli positions in relationship to changes in vertical dimension, by the shape of central bearing surfaces and by tooth contacts and functional movements. A pantograph was used on patients to study the effect of these variables. The results of this study indicate that several variables can affect graphic tracing of mandibular movements. The effects of these variables were shown and suggestions were made to reduce the inconsistencies found in studies using graphic tracings. Research criteria were suggested for conducting and reporting the results of studies of mandibular movements.

Pantographic tracings of mandibular movements and occlusion

Abstract Inconsistencies exist in the literature concerning the relationship of functional mandibular movements and border tracings recorded by pantographs. This study was undertaken to determine the relationship of functional movement and border tracings. A pantograph was assembled to clutches attached to anterior teeth. Chewing studies were performed on four subjects using different test foods. The functional movements of two subjects contacted the border tracing frequently from centric relation while the functional movements of two subjects were restricted to the tracings made from centric occlusion and influenced by occlusal interferences. The occlusion of one of the subjects with restricted functional movements was adjusted, and subsequently, the functional movements frequently contacted the border tracings. This study suggests that occlusion in harmony with border tracings may be the most physiologic.

Patients with restored occlusions. Part I : TMJ dysfunction determined by a pantographic reproducibility index

In a population of 50 subjects restored with fixed prostheses, the prevalence of TMJ dysfunction was 38% slight, 20% moderate, and 10% severe for a total of 68% showing some degree of dysfunction as recorded by pantographic tracings quantitated by the PRI. SD varied between categories. Higher PRI scores produced larger SD. The SD was 2.96 for the reproducible category, increasing progressively in each category, to 12.91 for the severe dysfunction category. The one session (four sets of tracings) used in the study to determine the degree of TMJ dysfunction appeared to be an accurate sample of a subjects PRI score for a given time. Control subjects scores appeared to stay relatively stable (p = .3649) over a period of time (1 to 3 months). While the scores did fluctuate, the category remained essentially the same. Those subjects with higher PRI scores showed the most fluctuation. The results indicated that pantographic tracings quantitated by the PRI can be used as a suitable instrument in epidemiologic studies to determine the prevalence of TMJ dysfunction.

Restored occlusions. Part II: The relationship of clinical and subjective symptoms to varying degrees of TMJ dysfunction

Fifty subjects restored with fixed restorations were examined by means of pantographic tracings and the PRI in order to determine the prevalence of TMJ dysfunction. In addition to the prevalence of dysfunction, the PRI categorized subjects as to the degree of dysfunction and clinical and subjective symptoms were related to the varying degrees of dysfunction. There were positive relationships (X)2 between the PRI categories and any dysfunction and many of the variables at the 0.1 level. There were positive correlations (Spearman R) at the 0.5 level between PRI categories and any level of TMJ dysfunction and many variables. The absence of clinical symptoms did not always indicate the absence of dysfunction as determined by the PRI.

Influence of TMJ dysfunction on Bennett movement as recorded by a modified pantograph. Part III: Progress report on the clinical study

The purpose of this investigation was to provide further insight into the characteristics of the induced and voluntary Bennett movement by determining the influence of TMJ dysfunction on the lateral side shift of the mandible as recorded by a modified pantograph. Twelve subjects were examined using pantographic tracings quantitated with the PRI to establish a baseline pattern of dysfunction for each subject. The PRI was used to categorize the subjects as to the degree of dysfunction. Following categorization, eight subjects were used as an experimental group and for subjects as a control group. On all subjects, induced and voluntary Bennett movement registrations were taken at the initial and final adjustment. Only the experimental subjects underwent an occlusal therapy consisting of an occlusal splint and an occlusal adjustment. Success of the therapy was monitored via the PRI. Following occlusal therapy, the reduction in PRI scores and categorization for the experimental group was significant to the 0.0042 level. There was no significant change inthe scores for the control group. Post-treatment Bennett movement registrations (voluntary and induced) indicated a statistically significant increase of the movement at the 0.043 level. The control group showed no significant change. Furthermore, on all subjects studied in this investigation, the voluntary Bennett movement was always within the borders of the induced Bennett movement, suggesting that the subjects neuromusculature was an important component in registering the lateral side shift of the mandible.

A pantographic reproducibility index for use in diagnosing temporomandibular joint dysfunction: A report on research

The pantographic reproducibility index (PRI) has been developed to quantitate incoordinated mandibular movements; one of the signs and symptoms of TMJ dysfunction. The PRI has been proven valid clinically in controlled research using more than 200 patients and scoring more than 2300 pantographic tracings during the past 10 years. The PRI can be used to determine (1) the presence or absence of TMJ dysfunction; (2) the success of treatment modalities such as occlusal splints, occlusal adjustments, and restorative treatments; (3) the prevalence of TMJ dysfunction; and (4) the level of TMJ dysfunction on experimental patients.