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Surface treatment of indirect resin composite surfaces before cementation
1Department of Restorative Sciences, Baylor College of Dentistry, Dallas, Texas.
Statement Of Problem:
Controversy surrounds the use of hydrofluoric acid to prepare precementation surfaces of indirect composites.
Purpose:
This study was conducted to compare effects of combining hydrofluoric or orthophosphoric acid with microetching as precementation treatments.
Material And Methods:
Nine specimens of three composite materials were prepared to simulate heat-cured indirect restorations. The specimen surfaces were prepared with one of three treatments. Adhesive Bond II and Twinlook cements were used to bond a phosphoric acid-etched disk of P50 to the treated surface. Analysis of variance and Scheffé tests were used to assess the bond strength data. Scanning electron microscopy and microscopic analysis of the fractured and treated surfaces were also performed.
Results:
Bond strengths for all surface treatments did not significantly differ. Hybrids had a higher bond strength with etching than microfills, and mechanical roughening produced the greatest bond strengths with microfills. Microetching with orthophosphoric acid produced higher bond strengths than microetching with hydrofluoric acid on hybrids.
Conclusions:
Acid etching alone is not sufficient to produce effective bond strengths, and hydrofluoric acid treatments are detrimental to the resin composite.