Improved Retention of Composite Bonded to Unetched-ER: YAG Laser Surface Modified Dentin

Objectives: This study compared the retention of composite bonded to laser-etched, drill-etched, and laser-unetched dentin surface on natural teeth by measuring resistance to dislodgement.
Methods: Twenty-two extracted permanent mandibular molars were sectioned bucco-lingually, and 1x2mm cavities were prepared on the coronal dentin using laser and drill on one half, and laser on the other half. Composite was bonded on the etched surface of drill- and laser-prepared, and unetched laser-prepared dentin with a 2mm overhang. Using triaxial machine, the force that dislodges or resists dislodgement and the number of dislodged and retained composites were evaluated.
Results: Results showed that there is no significant difference in the forces that dislodged and did not dislodge the composites, F(2,63) =1.21, p=0.31 (two-tailed) among the 3 groups. However, significant difference in the counts of dislodged and retained composites was observed among the 3 groups, X²(2) =7.7, p=0.02. Using Chi-square partitioning, a significant difference between laser-unetched and drill-etched dentin, X²(1) =7.5, p=0.006, and no difference between laser-etched and drill-etched, X²(1) =0.83, p=0.36 were observed.
Conclusions: The study showed that retention of composite in dentin was higher using laser without etching. In addition, ER:YAG laser without etching provides more efficiency and convenience because less chair time can be offered to patients. ER:YAG laser without etching is an available treatment modality for cavity preparations to receive composite restorations.