Date of Award

12-2012

Document Type

Thesis

Degree Name

Master of Dental Science (MDS)

Program

Prosthodontics

Research Advisor

David R. Cagna, DMD, MS

Committee

Swati Ahuja, BDS, MS William McHorris, DDS Gregory Paprocki, DDS Mark Scarbecz, PhD Russell Wicks, DDS, MS

Abstract

One goal of restorative dentistry is to truly capture maxillomandibular relationships that accurately reproduce mandibular border movements and that would prescribe the best occlusal interface. Registration of horizontal and sagittal movements of the patient allows maximum cusp height and fossae depth with proper placement of occlusal ridges and grooves. The goal is to develop an occlusion that is interference free and entails the concepts of organic occlusion. Methods to transfer patient information to a highly adjustable articulator include mechanical recorders, mechano-electronic recorders and optoelectronic recorders. The purpose of this study is to verify the accuracy of electronic mandibular movement recording devices in vitro. For this investigation an articulator (Denar® D5A, Whip Mix Corp., Louisville, KY) with known condylar settings was employed as a mock patient. An experimental apparatus was fabricated to attach recording devices to the mock patient simulating clinical conditions. Mock patient movements were accomplished under clinically relevant conditions.

The primary use of a pantograph is to record patient mandibular border movement and program an articulator so that the movements of the articulator simulate the border movements of the patient. The objectives of this four part investigation was to assess the accuracy of an optoelectronic pantograph (Freecorder® Bluefox, Dentron, Germany) in locating a known transverse horizontal axis (THA), assess the ability of an optoelectronic pantograph (Freecorder® Bluefox, Dentron) to accurately determine preset values of the mock patient, assess the ability of a mechano-electronic pantograph (Cadiax Compact 2®, GAMMA Dental, Austria) to accurately determine the preset values of the mock patient and compare the accuracy of the optoelectronic pantograph and mechano-electronic pantograph through statistical analysis mean values generated for each condylar setting were compared to known mock patient condylar settings. Settings were the same for the right and left condylar guide assemblies.

Results of this investigation demonstrated that: 1) the optoelectronic pantograph did not locate a known transverse horizontal axis; 2) the optoelectronic pantograph did not record mandibular movement accurately; 3) the mechano-electronic pantograph did not record mandibular movement accurately; and 4) there were differences in accuracy between the optoelectronic pantograph and mechano-electronic pantograph.

The majority of condylar guide assembly mean values predicted by the optoelectronic pantograph and mechano-electronic pantograph were statistically inaccurate and there were differences in accuracy between the optoelectronic and mechano-electronic pantographs. Clinically, the predicted mean values for the Lateral Condylar Inclination (LCI) and Progressive Mandibular Lateral Translation (PMLT) were within five degrees of the known mock patient settings. The values predicted by the optoelectronic pantograph over-compensated mandibular movement requiring shorter cusps for the restoration. The mechano-electronic pantograph prescribed longer cusps, for the restoration, that potentially induce interferences. Though statistically significant inaccuracies were identified, both mandibular recording devices may be considered clinically acceptable. However, the use of both mandibular recording devices investigated here will potentially result in occlusal restorations that require adjustment when placed in the oral cavity.

DOI

10.21007/etd.cghs.2012.0021

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