All ETDs from UAB

Advisory Committee Chair

John O Burgess

Advisory Committee Members

Jack E Lemons

Alan W Eberhardt

Lance C Ramp

Deniz Cakir-Ustun

Amjad Javed

Document Type

Thesis

Date of Award

2012

Degree Name by School

Master of Science (MS) School of Dentistry

Abstract

Dental ceramics are known for their excellent chemical and optical properties. The wear of human enamel and of the restorative material is often a vital and esthetical concern when selecting a restorative material for any given clinical restorative treatment. Objective: The purpose of the study was to evaluate effect of zirconia (polished, glazed, polished then glazed, adjusted, glazed and adjusted, adjusted and polished and aged zirconia) against human enamel antagonist. A comparison was made between different zirconia, veneering porcelain (Ceramco 3) and natural enamel. Additionally, the surface roughness (Ra) of the ceramic surface was measured before and after wear testing to evaluate effect of cyclic loading on the t-m phase transformation. Materials and methods: The study included zirconia specimens (n=8), (divided into polished, glazed, polished and then glazed, adjusted, glazed and adjusted, polished and adjusted and aged zirconia, a veneering ceramic (Ceramco3) and an enamel (control) group. Freshly extracted and caries free mandibular 1st molars were selected to serve as antagonists. Their mesio-buccal cusps were standardized, mounted onto steel styli, stabilized with self-cure acrylic and finally cleaned with pumice. Before testing, the surface roughness of all ceramic specimens was measured using a non-contact 3D surface profilometer (Proscan 2000, UK). All specimens were mounted into brass holders and subjected to cyclic loading in newly developed UAB-chewing simulator for 400,000 cycles. The antagonist applied a vertical load of 10N onto ceramic specimens stabilized on a 2mm horizontal sliding platform at a frequency of 20cycles/min. A solution of 33% glycerin + 66% water was continuously cycled through specimens for lubrication. PVS impressions of the enamel antagonist will be taken at the baseline, 200,000 and 400,000 cycles and poured with die stone. To measure enamel and ceramic wear, 3D scans of the stone model, ceramic block, and incisor surfaces were obtained after 200,000 and 400,000 cycles with a non-contact surface profilometer (Proscan 2000, UK). To determine the volume and the depth loss, the 3D scans were superimposed with PROFORM software. Results: Data was analyzed by ANOVA and Tukey post-hoc tests (p=0.05).

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Dentistry Commons

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