Abstract

Laser etching of enamel surfaces alters the physical and chemical characteristics of the enamel. These changes in characteristics enhance the bonding to enamel. The purpose of this study was to compare the shear and tensile bond strength of Er,Cr:YSGG hydrokinetic laser system (Biolase) with 37% phosphoric acid and self etching primer 30 minutes and 72 hours after bonding. Four different laser power output setting was observed: 1.5W, 2.0W, 2.5W, and 3.0W. Two hundred forty bovine teeth free of defect, caries, and dentin exposure were mounted in acrylic resin and divided into 24 groups of 10 teeth. Sixteen groups of 10 teeth were exposed to the laser (40 teeth for each of the 4 different laser power output settings). Four groups of 10 teeth were etched with 37% phosphoric acid and another 4 groups of 10 teeth with the self-etching primer. The lingual buttons were bonded with Transbond XT and cured for 20 seconds per side mesial and distal to the lingual button. Shear and tensile bond strength were determined with a MTS universal testing machine 30 minutes and 72 hours after bonding. Statistical analyses included the Kruskall-Wallis ranks test and Wilcoxon-Mann-Whitney rank sum test. Two teeth for each of the laser output settings, acid etched, and self etch primer were examined with a Zeiss LSM 510 laser confocal microscope at three different areas of each tooth. The topographical characteristics of laser etching were completely different from acid etch and self etch primer. The tensile and shear bond strength at 30 minutes and 72 hours of the laser at all power output settings were significantly less than acid etching (p < .0001). The X-Y positioner allowed for a more standardized laser etching procedure than by hand laser etching. However, the low maximum velocity and inability to control the Y component for this particular X-Y positioner may not have produced an optimal etched surface. The mode of bond failure for the laser etching occurred mainly at the enamel-adhesive junction (91%). Although Er,Cr:YSGG laser have many use in dentistry, the use of this laser for the sole purpose of enamel etching cannot be recommended as an alternative to the traditional acid etch for increasing the bond strengths to enamel.

LLU Discipline

Orthodontics and Dentofacial Orthopedics

Department

Dentistry

School

Graduate School

First Advisor

Carlos A. Munoz

Second Advisor

Joseph M. Caruso

Third Advisor

James Jessee

Fourth Advisor

Jay S. Kim

Degree Name

Master of Science (MS)

Degree Level

M.S.

Year Degree Awarded

2003

Date (Title Page)

12-2003

Language

English

Library of Congress/MESH Subject Headings

Dental Enamel; Dental Bonding; Dental Materials; Dental Etching

Type

Thesis

Page Count

viii; 46

Digital Format

PDF

Digital Publisher

Loma Linda University Libraries

Usage Rights

This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.

Collection

Loma Linda University Electronic Theses and Dissertations

Collection Website

http://scholarsrepository.llu.edu/etd/

Repository

Loma Linda University. Del E. Webb Memorial Library. University Archives

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