| 3125 The Influence of Conditioning Time on Enamel Adhesion | ||
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J. PERDIGAO1, G. GOMES2, V.M. AUGUSTO3, S. DUARTE, Jr.4, M.M. LOPES1, and J.R. PERDIGAO1, 1University of Minnesota, Minneapolis, USA, 2Private Practice, S. Domingos de Rana, Portugal, 3Private Clinic, Oeiras, Portugal, 4University of Minnesota, Sao Paulo State University, Minneapolis, USA Objectives: To calculate enamel bond strengths of 5 enamel adhesives in function of conditioning time. Methods: The proximal surfaces of 30 extracted molars (60 bonding surfaces, 8.0 X 4.0mm2) were roughened with a diamond bur for 5 sec and assigned to 5 adhesives: AdheSE (ADS, Ivoclar Vivadent, pH≈1.6); Adper Prompt L-Pop (APL, 3M ESPE, pH≈1.0); Clearfil SE Bond (CSE, Kuraray, pH≈2.1); Prime&Bond NT (PBNT, Dentsply, pH of 34% H3PO4 gel≈0.5), the total-etch control; and Tyrian SPE/One-Step Plus (TYR, Bisco, pH≈1.2). For half of the bonding surfaces the adhesives were applied as per the manufacturers' directions. For the remaining half, enamel conditioning time was twice as long as that recommended by the manufacturer. Buildups were constructed with Filtek Z250 (3M ESPE). The bonded specimens were sectioned in sticks with a cross section of 0.8±0.2 mm2 and tested in tension at a crosshead speed of 1 mm/min. Data were analyzed with 2-way ANOVA and Duncan's test at p<0.05. Results: TYR and PBNT ranked in the highest subset regardless of the application time of the enamel conditioner. CSE and ADL also ranked in the highest subset for double application time of the self-etching primer. When means were pooled for application time, TYR and PBNT resulted in the highest mean bond strengths, which were significantly higher than those of APL, CSE, and ADS at p<0.05. ADS resulted in statistically lower mean bond strengths than any other enamel adhesive. When the means were pooled for enamel adhesive, the double application time resulted in statistically higher bond strengths than the recommended application time at p<0.015. ADS and CSE were the only adhesives for which double application time resulted in statistically higher enamel bond strengths than the recommended application time. Conclusions: doubling the enamel conditioning time results in higher bond strengths for self-etching primers with higher pH. | ||
| Seq #335 - Adhesion III 10:15 AM-11:30 AM, Saturday, 13 March 2004 Hawaii Convention Center Exhibit Hall 1-2 | ||
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