Occlusion in the Digital Age
Abstract
Purpose
Current technology is capable of manipulating and analyzing the dentition digitally, in all three planes of space. Our goal is to use 3D technology to help identify barriers to ideal occlusion in the posterior dentition that may have been previously overlooked. Materials and Methods 50 pre-treatment models (30 male, 20 female, mean age= 15.9±2.8 years) were scanned using a TRIOS ® 3Shape scanner. The models were digitized, and the posterior dentition was manipulated into ideal cusp-fossa relationships, using Ortho Analyzer™ software, following a seven-step manipulation protocol. The protocol was based on achieving Andrew’s Six Keys to Ideal Occlusion4 as well as a large number of ideal occlusal contacts. After manipulation was complete, all overlaps >0.05 mm or spacing between interdental contacts were recorded as a discrepancy. The sum of the absolute value of all discrepancies was recorded as the total discrepancy on each side. The left and right sides were compared using a Wilcoxon signed ranks test.
Results
In the 50 models evaluated, 62 discrepancies were detected. Approximately 5% of the discrepancies detected were at the canine- 1st premolar contact, 3% of discrepancies were located between at the 1st and 2nd premolar contact, 84% were at the 2nd premolar- 1st molar contact and 8% of the discrepancies were between the 1st and 2nd molar contact. The 2nd premolar -1st molar contacts, which showed the highest prevalence of contact discrepancies, showed median discrepancies of 0.5 and 0.4 mm on the left and right sides, respectively. Over half of the sides evaluated had a discrepancy at this contact point. In terms of subjects, 64% of individuals had at least one side with a discrepancy at this contact point. Concerning total discrepancies, approximately 50% on the left and right sides were greater than 0.56 mm and 0.47 mm, respectively. Approximately 46% of sides had no total discrepancy. 25% of sides had total discrepancies that were ≥0.05 mm but 0.09).
Conclusions
Discrepancies in the posterior dentition are not uncommon, with approximately 6% of posterior contacts, 29% of sides, and 44% of individuals having clinically significant discrepancies (discrepancies greater ≥0.5 mm). The maxillary 2nd premolar- maxillary 1st molar contact may be a common contributor to occlusal discrepancies. Evaluating the cusp tip of the maxillary 2nd premolar relative to its embrasure may provide insight to the possibility of a class I canine position. In 92% of the posterior dentitions evaluated, if the Maxillary 2nd Premolar was placed appropriately according to the manipulation protocol, the remaining premolars and canines were able to class I cusp-fossa relationship without any interferences. The utilization of 3D technology may help the clinician as a diagnostic aid and yield insight into potential barriers to ideal occlusal results.
Citation
Savage, Jackson David (2021). Occlusion in the Digital Age. Master's thesis, Texas A&M University. Available electronically from https : / /hdl .handle .net /1969 .1 /195716.