Date of Award

Spring 2015

Document Type

Thesis - Restricted

Degree Name

Master of Science (MS)

Department

Dentistry

First Advisor

Berzins, David

Second Advisor

Thompson, Geoffrey

Third Advisor

Cho, Seok Hwan

Abstract

Purpose: A polymer infiltrated ceramic network (PICN) and a resin nano ceramic (RNC) restorative materials for Computer Aided Design/Computer Aided Manufacturing (CAD/CAM) applications recently became commercially available. Little independent evidence regarding their mechanical properties exists to facilitate material selection process. The purpose of this study was to measure the edge chipping resistance and flexural strength of the novel PICN and RNC materials and compare it to two commonly used feldspathic ceramic (FC) and leucite reinforced glass-ceramic (LRGC) CAD/CAM materials that share the same indications. Materials and Methods: For the edge chipping test, 20 specimens/group were tested. Square prism specimens 10 ~ 10 ~ 2mm were sectioned from the commercially available CAD/CAM blocks, polished and adhesively attached on a 4mm thick resin bed fabricated in a custom holder. A 120 degree sharp conical indenter was mounted on a universal testing machine and the specimens edge was positioned in distances varying from 0.1mm to 0.7mm horizontally from the indenter tip. Two edge chipping tests were performed per sample at a crosshead speed of 0.1mm/min and the critical force at which a chip spalled off the edge was recorded. One-way ANOVA determined intergroup differences (f¿=.05). For the flexural strength test, 22 specimens/group were tested. Beam specimens 18 ~ 4 ~ 1.2mm were sectioned from the commercially available CAD/CAM blocks and polished. A 3-point flexure test was performed on a universal testing machine with a test fixture support span of 15mm and the crosshead speed set at 0.5mm/min. Weibull statistics determined intergroup differences (f¿=.05). Flexural modulus and work of fracture were also measured and one-way ANOVA determined intergroup differences (f¿=.05). Results: Regarding edge chipping resistance, one-way ANOVA revealed significant differences with the materials ranking RNC>LRGC=FC>PICN (P=.05). Regarding flexural strength, Weibull statistics revealed significant differences with the materials ranking RNC=LRGC>PICN>FC (P=.05). Regarding flexural modulus one-way ANOVA revealed significant differences between the 4 materials, which ranked RNC LRGC=PICN>FC (P=.05). Conclusions: The RNC material demonstrated superior results for all the mechanical properties tested compared to the other 3 materials. Randomized controlled trials to determine clinical success are warranted for the RNC material.

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