Laser type effects on repair bond strength of ormocers and nanoceramic based composites

The aim of this study was to evaluate the effects of different surface treatments and different restoration materials on repair bond strength of ormocer and nanoceramic based composites. 24 (12 Admira, Voco, 12 Ceram X duo, Dentsply) thermally aged blocks (6 × 6 × 5 mm) were roughened with either bur, Er:YAG or Nd:YAG laser. In each group half of the roughened samples were repaired with composite of their respective brand; other half was repaired with composite of the other brand. All samples were subjected to microtensile bond strength test. Data were analyzed with Kruskal-Wallis and Bonferroni correction, Mann-Whitney U test (p = 0.05). For roughening methods no significant difference was found between Bur-Er:YAG (p = 0.536), however between the other groups (Bur-Nd:YAG and Er:YAG-Nd:YAG) significant difference were found (p < 0.001). For Admira as a filler material, no significant differences were found for bur, Er:YAG, Nd:YAG groups based on repair materials. For Ceram X duo as a filler material, while no significant differences were found for bur and Er:YAG groups; a significant difference was found for Nd:YAG group based on repair materials. A weak significant difference was found between the repair composite groups undergone thermocycling or not (p = 0.04). Surface roughening with Er:YAG laser can be used clinically for the repair of aged composite restorations.