Date of Award

Spring 1994

Document Type

Thesis - Restricted

Degree Name

Master of Science (MS)

Department

Dentistry

First Advisor

Dhura, Virendra B.

Second Advisor

Ferguson, Donald J.

Third Advisor

Gannon, Michael

Abstract

Bondable metal brackets are popular appliances in contemporary orthodontics. Anatomical features of bracket bases have continuously changed in an effort to increase bracket retention. A relatively new technique called microetching has been proposed to increase bracket-adhesive bond strength. Microetching is a form of sandblasting with fine particle aluminum-oxide abrasive. This is utilized to highly roughen metal bracket bases for added micromechanical retention. This experiment was designed to evaluate the tensile bond failure load of three commercially available metal bracket bases with and without microetching. The following bracket bases were utilized: a 100 gauge foil mesh base, a 200 /100 double layered foil mesh base, and a sintered base with undercut metal projections and peripheral lip. Ninety bovine incisors were randomly assigned to six sample groups, mounted in acrylic cylinders and prepared for bonding. Bracket bases were microetched prior to bonding if required of the sample. After bonding with a highly filled orthodontic adhesive, teeth were stored in water for 48 hours before testing. The tensile load necessary to produce bond failure was delivered by an Instron machine and recorded. The site of bond failure was evaluated under stereo microscope and recorded. Based on the results of this study, the following conclusions were obtained: 1. The sintered base with undercut projections and peripheral lip was significantly more retentive than the 200/100 double mesh base and the 100 mesh base (p

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