Abstract
•Laser therapies are useful for reducing microleakage, and hence increase the bond strength of resin based restorative materials bonded to tooth structure.•The specimens conditioned by NaOCl showed the lowest microshear bond strength in hypoplastic teeth•APDT showed the highest bond strength values (∼22 MPa)•Microscopic analysis revealed that specimens bonded after APDT showed the highest adhesive failures (70%).•The highest cohesive failures were seen in NaOCl group (40%).
This study investigates the micro shear bond strength of resin-modified glass ionomer cement (RMGIC) bonded to hypoplastic teeth after the application of chlorhexidine (CHX), sodium hypochlorite (NaOCl), Er;Cr:YSGG and methylene blue mediated antimicrobial photodynamic therapy (APDT).
A total sample of 60 erupted and extracted hypoplastic teeth collected from < 16 years children were subjected to different conditioning protocols including control group that involved bonding of hypoplastic teeth with RMGIC; CHX and NaOCl groups that included hypoplastic enamel being treated with 0.2% CHX and 2% NaOCl solution for 30 s followed by rinsing and drying for 5 s, MB–PDT group involved methylene blue photosensitizer and Er,Cr:YSGG group. All specimens were processed for microshear bond strength in a universal tester. The fractured surface was examined using a stereomicroscope at 40 × magnification and categorized under adhesive, cohesive and mixed.
The highest microshear bond strength was noted for the control group (∼29 MPa). Whereas the specimens conditioned by NaOCl showed the lowest microshear bond strength (∼17 MPa). Among the treatment groups, APDT showed the highest bond strength values (∼22 MPa) as compared to chemical disinfection protocols. However, Er, Cr:YSGG showed slightly lower microshear bond strength as compared to APDT. No significant difference was noted between CHX and NaOCl groups (p > 0.05). There was a statistically significant difference when all the groups were compared together (p < 0.05). Microscopic analysis revealed that specimens bonded after APDT showed the highest adhesive failures (70%). The highest cohesive failures were seen in NaOCl group (40%). The mixed type of failures was seen in the control groups with none appearing for chemical disinfection protocols.
This study concludes that APDT could be a potential therapeutic strategy for increasing the microshear bond strength of RMGIC to hypoplastic enamel.