• Chalermkwan Phuvoravan D.D.S., M.Sc., (Endodontics)
• Rattanavadi Tanchanapradit D.D.S.
• Naratip Rachawang D.D.S.

Objective This study investigated the effect of eugenol-containing root canal sealer on shear bond
strength of resin composite, and the effect of 3 different eugenol-cleansing techniques on shear bond
strength of composite restoration.

Materials and methods Occlusal surfaces of 50 extracted caries-free human third molars were mounted
and horizontally sectioned at middle dentin to obtain a flat dentin surface. Teeth were randomly divided
into 5 groups (10 teeth each). Dentin surface in group 1 (negative control) was not contaminated with
eugenol-containing sealer. In groups 2 to 5, dentin surfaces were painted with eugenol-containing
sealer and left for 30 minutes. Then, contaminated surfaces were cleaned with dry cotton pellet (group
2, as a positive control), 70% alcohol (group 3), 5% acetic acid (group 4) and acetone (group 5),
respectively. Composite columns (5 mm in diameter, 2 mm in height) were built using a total-etch
dentin bonding agent. All specimens were cured, and shear bond strength was measured using an
Instron universal testing machine at a cross-head speed of 0.5 mm/min.

Results Mean shear bond strength in group 4 (cotton pellet soaked with 5% acetic acid) showed the
highest value of 18.59 MPa, followed closely by the non-contaminated group (group 1). Whereas
group 2 (dry cotton pellet, without solution) showed the lowest mean shear bond strength of 14.42
MPa. One-way ANOVA analysis revealed statistically significant differences between groups 1 and 2,
2 and 4, 3 and 4 (p < 0.05) respectively.

Conclusion Based on the results of this study, dentin shear bond strength of composite built-up was
influenced by contamination of eugenol-containing root canal sealer, and by different cleansing
techniques. Cotton pellet soaked with 5% acetic acid was the most effective method to eliminate
eugenol-containing sealer.

(CU Dent J. 2011;34:203-12)