Date of Award

Spring 1996

Document Type

Thesis - Restricted

Degree Name

Master of Science (MS)

Department

Dentistry

First Advisor

Ferguson, Donald J.

Second Advisor

Kittleson, Russell

Third Advisor

Bradley, T. G.

Abstract

It is presumed that the more closely the design of the articulator mimics the anatomy of the human temporomandibular joint (TMJ)/jaw complex, the more likely it is to duplicate mandibular movement. The Polycentric Hinge Articulator (POLY) is promoted as an instrument that more precisely replicates the anatomy and function of the temporomandibular joint and mandible, thereby making the POLY a more accurate and efficient articulator. Designers of the POLY claim that their articulator more accurately replicates mandibular movement and chat clinicians using the POLY will spend less time adjusting appliances made in the laboratory with the POLY. They also advocate that increased accuracy of a dental appliance will improve patient comfort. The purpose of this research was to test the efficacy of the POLY and SAM-2 articulators by fabricating a cone-splint at ten millimeters of vertical opening on the respective articulators mounted in centric occlusion and by measuring the cone-to-tooth gap distances intraorally. Measurements were made on twenty subjects with a stainless steel feeler gauge. Cone-to-tooth gap differences were determined by using the Student's paired t-test. The results demonstrated that the mean gap distances for the POLY were uniformly less than the SAM-2 in all areas of the cone splint, although there was statistical difference only at the mandibular left mesio-buccal cusp tip (p=.033). The largest variable in the study was believed to be the neuromuscular component of each subject as they occluded onto the cone-splint. Research subjects had difficulty holding their mandible motionless as measurements were being recorded. lntraoperator error was found to be acceptable in the pre-recording period but quite large in the post-recording period. Hence, the issue of method reliability is brought into question. Also, cone-to-tooth gap distances were measured with a leaf gauge which possessed an interval scale rather than a continuous scale which may have decreased accuracy of the measurements. In conclusion, the alternative hypothesis (HA) was accepted at cone 5 which demonstrated a statistical difference, whereas the null hypothesis (Ho) was accepted for cone 1 through cone 4 which demonstrated no statistical difference at a probability level of p<0.05.

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