Date of Award

Spring 1997

Document Type

Thesis - Restricted

Degree Name

Master of Science (MS)

Department

Dentistry

First Advisor

Dhuru, Virendra B.

Second Advisor

Ferguson, Donald J.

Third Advisor

Kittleson, Russell T.

Abstract

The purpose of this investigation was to compare the bond failure loads obtained with indirect bonding (Indirect-I), with the "double sealant" technique (lndirect-2). This study was also designed to assess the amount of residual resin on the tooth surface after debonding by using a modified Adhesive Remnant Index (ARI). Eighty extracted human bicuspids were randomly assigned to one of three test groups. One group had brackets indirectly bonded as (Indirect- I), while the other two groups utilized the "double sealant" technique (lndirect-2 and Indirect-3). All the specimens were prepared for indirect bonding in the same manner. The Indirect-I method consisted of attaching a bracket to the stone model with a water soluble indirect bonding adhesive, making a silicone transfer tray, and bonding to the enamel surface with Phase II, a two paste filled composite adhesive resin system. The Indirect-2 method consisted of attaching a bracket to the stone model with Therma Cure, a filled composite resin, making a silicone transfer tray, and bonding only with an unfilled sealant resin. The Indirect-3 method was similar to the Indirect-2 method with one exception; the exception being that Adhesion Booster was used along with the unfilled sealant resin during the bonding procedure. The brackets in all three groups were subjected to a shearing load applied by the Instron testing machine and the debonding loads were recorded. The debonded specimens were observed under a stereomicroscope at 15X magnification and an Adhesive Remnant Index score was assigned to each tooth. Analysis of variance performed on the data showed significant differences in bond failure loads among the three test groups. The lndirect-2 technique had significantly lower bond failure loads as compared with the Indirect-I and lndirect-3 techniques (p<0.05). The "double sealant" techniques (lndirect-2 and lndirect-3) showed significantly lower adhesive remnant index (ARO scores as compared with the Indirect-I technique (p<0.05). The "double-sealant" technique (lndirect-3) utilizing the Adhesion Booster demonstrated adequate bond strength while also exhibiting the possibility of easier clean-up during the debonding procedure.

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