Semester

Summer

Date of Graduation

2014

Document Type

Thesis

Degree Type

MS

College

School of Dentistry

Department

Restorative Dentistry

Committee Chair

Mark Richards

Committee Co-Chair

Matthew Bryington

Committee Member

Michael Bagby

Committee Member

Matthew Bryington

Committee Member

Mohssen Ghalichebaf

Committee Member

Mark Richard

Abstract

Statement of problem: Acrylic resin removable dentures are susceptible to fracture after periods of clinical use. There are many predisposing clinical factors for these denture fractures. Specifically, acrylic resin fractures due to poor flexural strength has historical been a problem with complete denture.;Objective: The purpose of this in vitro study was to measure and compare the flexural strength of denture base acrylic resin processed by three different techniques: Conventional Pressure-Pack (compression molded) method, Injection molded (SR-Ivocap), and Computer Aided Design - Computer Assisted Manufacturing (CAD/CAM) (AvaDent(TM) Digital Dentures).;Methods: A total of 45 specimens (64 mm X 10 mm X varying thicknesses of 2 mm, 3 mm, and 5 mm) were fabricated, 15 for each of the three materials being tested. Specimens were tested according to the American Society for Testing and Materials (ASTM) standard D790-03 for flexural strength of reinforced plastics. The specimens were loaded until fracture or 15 mm of displacement on a three-point bending test machine (InstronRTM Model 5565 Universal Testing Machine).;Results: Data from this flexural strength study indicates that SR- Ivocap Injection Mold technique showed a higher flexural strength than CAD/CAM Avadent and Pressure-pack. When a 3 mm specimen was considered, statistically significant difference was apparent between Injection mold and the other two techniques (CAD/CAM and Pressure-Pack).;Conclusions: The flexural strength test is significantly useful in comparing denture base materials in which stress of this type is applied to the denture during mastication. The results from flexural test indicated that the differences observed can be attributed to the polymer constituents and to the method of polymerization. SR-Ivocap Injection Molding may prove to be more advantageous than CAD/CAM AvaDent(TM) and Pressure-Pack.

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