Use of personal computers for Gothic arch tracing: analysis and evaluation of horizontal mandibular positions with edentulous prosthesis.

STATEMENT OF PROBLEM: Determining mandibular position for an edentulous patient raises the question of whether to emphasize centric relation or muscular position. This challenge results from the lack of a convenient procedure for quantifying the horizontal mandibular position, which can be determined by a variety of methods.
PURPOSE: This study analyzed and evaluated the horizontal mandibular positions produced by different guidance systems.
MATERIAL AND METHODS: Twenty-six edentulous subjects with no clinical evidence of abnormality of temporomandibular disorder were selected. Horizontal position data for the mandible obtained by gothic arch tracing was loaded into a personal computer by setting the sensor portion of a digitizer into the oral cavity to serve as a miniature lightweight tracing board. By connecting this with a digitizer control circuit set in an extraoral location, each mandibular position was displayed in a distinguishable manner on a computer display in real time, then recorded and analyzed.
RESULTS: The gothic arch apex and tapping point varied, depending on body position. In the supine position, the gothic arch apex and the tapping point were close to the mandibular position determined by bilateral manipulation.
CONCLUSION: This system provides effective data concerning mandibular positions for fabrication of dentures.