Some clinicians advocate placing the bonding agent and the composite resin over it and curing them simultaneously to save time.  However that may produce lower bond strengths.  Objective: This study compared shear bond strengths of 3 self-etching bonding agents to enamel and dentin when the bonding agent was cured or uncured.  Methods:  120 extracted teeth were wet ground on a polisher grinder to 600 grit to create a flat bonding area on enamel and dentin.  The 3 bonding agents were applied following the manufacturers' directions except that half were not cured.  Curing was accomplished using an Optilux 501 curing light (output = 860 mW/cm²). Z-250 composite resin (shade A2) was placed into a Teflon tube, inserted over the adhesive and light cured from occlusal for 40 seconds. The specimens were stored in deionized water at room temperature until testing, when they were placed into an Instron testing machine, model 4411, and loaded in shear at a 1 mm per minute crosshead speed until failure.  Shear bond strength was analyzed with 3-factor ANOVA. Separate single-factor ANOVA models for substrate, cure, and material (by combinations of levels of the other two factors) were also analyzed. Tukey's HSD multiple comparison procedure was used to separate factor-level means. All testing was performed at the 5% significance level. Bond strength = MPa (n=10). Results: Highly significant differences (p<0.0001) were obtained for each factor. Enamel produced significantly greater bond strengths. Clearfil SE Bond was superior to Prompt L-Pop except for dentin no cure.

	Adper Prompt-L-Pop		Clearfil SE Bond		Xeno III
	Cure	No cure	Cure	No cure	Cure	No cure
Enamel	9±3	13.4±4	19±4	19±5	19±3	18±5
Dentin	9±3	5.4±2	16±3	6±2	13±5	4±3

Conclusions:  Curing the adhesive separately generally produces greater dentin shear bond strengths.

Back to the Dental Materials: I - Adhesion-Composite Bond Strength Program
Back to the IADR/AADR/CADR 82nd General Session (March 10-13, 2004)

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