Date of Award
Spring 2023
Document Type
Thesis
Degree Name
Master of Science (MS)
Department
Dentistry
Program
Prosthodontics
First Advisor
Keesler, Jack
Second Advisor
Ahmed, Ayman
Third Advisor
Waliszewski, Kenneth
Abstract
Objective: Recording the centric relation position is a critical step in diagnosis and treatment in prosthodontics. There are various methods that can be used to position a patient’s mandible into centric relation. Among these are: swallow technique (unguided closure), chin-point guidance, and bimanual manipulation. The precision of these methods has previously been studied by traditional methods. Data is lacking on the precision of virtual recordings of these methods taken by an intraoral scanner. The purpose of this study was to assess the digital precision of the swallow, chin-point guidance, and bimanual manipulation centric relation positioning techniques.Materials and Methods: Ten participants were included in the study. Their mandibles were positioned into centric relation by the swallow, chin-point guidance, and bimanual manipulation techniques while wearing a deprogrammer. Three trials of each technique were scanned with the Trios 4 (3Shape) intraoral scanner. The right side of the maxillomandibular relationship records were aligned, and 3D analysis was completed with a metrology software (Geomagic Control X, 3D Systems). F-tests were completed to assess for significant differences between two sample variances. Kruskal-Wallis tests assessed the differences in standard deviation across participants with a Bonferroni-corrected threshold of 0.0083 to adjust for multiple comparisons. Results: Pairwise comparisons of bimanual vs. swallow, bimanual vs. chin-point guidance, and swallow vs. chin-point guidance yielded statistically significant differences in standard deviation (each P<0.001). The maxillary and mandibular scans yielded statistically significantly different standard deviations (each P<0.001) within each method. Across each of the six method-region combinations, a non-significant difference was observed (each P>0.0083), indicating that there is insufficient evidence to suggest differences amongst the participants. Conclusion: The results of this study suggest that bimanual manipulation is the most precise centric relation positioning technique followed by chin-point guidance. The swallow technique is the least precise. All three techniques are clinically acceptable based on their adjusted mean and median standard deviations.