Date of Award

Spring 2016

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Dentistry

First Advisor

Thompson, Geoffrey A.

Second Advisor

Cho, Seok Hwan

Third Advisor

Ziebert, Gerald

Abstract

Purpose: The purpose of this vitro study was to evaluate the accuracy of the morphology of digitally trimmed dies in comparison with the subgingival contour of a prepared tooth to be restored with a single crown. Materials and Methods: 20 human extracted teeth, 10 incisors and 10 molars were disinfected, mounted on dentoforms. The teeth were prepared for a single all ceramic restoration. Digital impressions of the preparations were made using the 3M Lava COS. With the data, the SLA models were fabricated with removable dies. The prepared tooth and the corresponding dies were then compared with the Rhino software. Results: Three different parameters were tested angle, length and volume to compare the accuracy of the digital die to the subgingival morphology of the prepared teeth. Paired t test was used to compare the teeth to their corresponding dies. For the angle analysis of CAD/CAM die trim morphology, the incisor group demonstrated significant difference at the BL surfaces. On the contrary, the molar group showed significant difference at the MD surfaces. For the evaluation of length and volume of CAD/CAM die trim morphology, the incisor group showed significant difference at zone D of both BL and MD surfaces. However, significant differences at zone C and D of BL surfaces and all zones of MD surfaces was noticed in the molar group. Conclusions: Within the limitations of this study, the following conclusion was made: Incisor group - the CAD/CAM (SLA) dies were bigger in the Zone D in both BL and MD direction. Molar group – the CAD/CAM dies were bigger in all the zones in both BL and MD direction. The angle measurements showed the teeth had a tendency to be more narrow and flat while the SLA dies were more concave.

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