Abstract

Objective: To compare the dentin shear bond strength of three self-etching bonding agents with that of a conventional total-etch bonding system.

Materials & Method: Extracted third molars (120) were fixed in 10% formalin and randomly divided into eight groups of 15 specimens each. The specimens were mounted in acrylic resin and the surface ground to expose superficial dentin. A standardized smear layer was created by polishing the surfaces with wet 600-grit silicon carbide paper. Each adhesive system was placed on the specimen surface according to the manufacturers' instructions. The specimen then was mounted onto a standardized jig and light cured. Composite stubs of 2.38 mm in diameter and 3 mm high were placed directly on top of the bonding agent using incremental layers of Z250, shade A1 composite.

Each sample was paired randomly for testing under two different conditions: thermocycled and non-thermocycled. In the non-thermocycled group, samples were incubated for 24 hours at 37°C while the thermocycled group was cycled 750 times in alternating baths of 5°C and 55°C with a 20 second dwell time in each bath.

The bonds were subsequently stressed to failure using a universal material testing machine operating at a crosshead speed of 1 mm/min. The mean de-bonding force was measured in Newtons (N) and converted to Megapascals (MPa) for statistical analysis. Analysis was performed using the Mann-Whitney U-Test. The sample surfaces were subsequently examined under a stereomicroscope to assess the percentage of cohesive and adhesive failure.

Results: Mean results were given (MPa) for the non-thermocycled and thermocycled samples. (Scotchbond= 38.3 ± 4.5 and 30.1 ± 4.9; G-Bond= 25.4 ± 3.1 and 19.6 ± 2.2; L-Pop=23.9 ± 2.9 and 20.3 ± 3.2; Brush & Bond= 30.0 ± 4.5 and 29.5 ± 2.5). In both the non-thermocycled and thermocycled groups, the control had statistically greater bond strengths than G-Bond, L-Pop, or Brush & Bond (p< 0.05).

Conclusions: The shear bond strength of the total-etch system (control) was statistically higher than that of the self-etch systems. However, under conditions of the present study, the self-etch bonding systems investigated were capable of providing adequate dentin bond strengths.

LLU Discipline

Pediatric Dentistry

School

Graduate Studies

First Advisor

John Peterson

Second Advisor

Jay Kim

Third Advisor

Yiming Li

Fourth Advisor

J. Todd Milledge

Fifth Advisor

Bonnie Nelson

Degree Name

Master of Science (MS)

Degree Level

M.S.

Year Degree Awarded

2006

Date (Title Page)

6-2006

Language

English

Library of Congress/MESH Subject Headings

Dental Bonding; Dental Materials; Dental Etching; Composite Resins

Type

Thesis

Page Count

x; 18

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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