How do increased irradiance and exposure time affect the repair bond strength of universal adhesives to CAD-CAM composite material?

PURPOSE: This study was designed to investigate the effects of increased exposure time and different levels of irradiance on the repair bond strength (µTBS) and degree of conversion (DoC) of two universal adhesives. METHODS: were obtained from the repaired blocks and subsequently tested in a micro-tensile testing machine. Additionally, the DoC was assessed using micro-Raman spectroscopy. RESULTS: The 1400*10 group of GBU and CSU demonstrated higher µTBS than the 1000*10 and 1400*15 groups, regardless of thermal cycling (P = 0.000). For CSU, the 1400*10 group showed the highest DoC (P < 0.05). However, the DoC of GBU did not differ significantly among the various irradiation/exposure times (P > 0.05). CONCLUSION: ) increases the repair µTBS and DoC regardless of thermal cycling.