Effects of diode laser and MTAD on the push-out bond strength of mineral trioxide aggregate-dentin interface

The aim of this in vitro study was to evaluate the effects of diode laser, MTAD(™) and laser plus MTAD on the push-out bond strength of mineral trioxide aggregate (MTA)-dentin.

MTA has been used widely, especially in root canal therapies (RCT); however, the effect of different final treatments during RCT has been questioned regarding the retention characteristic of this cement-based material.

Forty single-rooted human teeth were prepared into dentin slices and drilled to form canal spaces. Samples were divided into four groups of 10 in each (n=10). In groups A and B, diode laser irradiations were performed, and then MTA was placed inside the canal spaces and incubated at 37 °C for 7 days. After incubation, dentin slices in groups B and C were immersed in Biopure MTAD, and the last group served as control without any treatment. The push-out bond strengths were then measured by using a universal testing machine.

The means±standard deviations of push-out bond strength were 6.74±0.48, 5.95±0.40, 6.86±0.66, and 7.88±0.37 for groups A (laser), B (laser plus MTAD), C (MTAD) and D (control), respectively. One-way analysis of variance (ANOVA) test revealed significant differences among the groups (p<0.0001). Tukey's test did not show any significant difference between groups A and C (p=0.93). However, these differences were significant between groups A and B (p=0.006) and between groups B and C (p=0.001).

The results of this study indicated that either diode laser or MTAD can lower the bond strength of MTA-dentin, and that diode laser irradiations plus MTAD might affect MTA bond to dentin negatively.