Microtensile bond strength of different modes of universal adhesives to radiotherapy-affected dentin

Objective Radiotherapy (RT) beams are proved to have detrimental effects on dental tissues. Aim of the present study was to evaluate the microtensile bond strengths of different modes of universal adhesives on RT-effected dentin. Methods: One hundred and twenty premolars of patients who had not diagnosed with any systemic disease and 120 premolars of patients who had undergone >50 Gy (Gray) dose of radiotherapy 6–9 months ago were extracted. Teeth were sectioned perpendicularly to expose superficial dentin. Different adhesive modes [etch-and-rinse (ER), selective-etch (SE)] of universal adhesives [Single Bond Universal (SBU), Prime&Bond Universal (PBU)] were formed the 8 groups of the study (n = 30). After composite build-ups were bonded to dentin, samples were sectioned into microspecimens. Then, these specimens were subjected to micro-tensile bond strength test. Data were analyzed by t-test at p < 0.05. Results: Except for the PBU-SE group, control group had higher bond strength than treatment group. In treatment group, SBU-ER showed the highest bond strength followed by PBU-SE and SBU-SE (p > 0.05). PBU-ER had the lowest bond strength among all groups. There is also statistical significance between all modes of two universal adhesives (p < 0.05). Adhesive fracture was the most predominant in groups. Conclusion: Design of the methodology ensures the dentin samples of treatment group to benefit from oral condition changes after RT. According to results, only Prime&Etch Universal adhesive is recommended to be used in SE mode. In order to gain a common protocol for material choices, it is necessary to plan studies with similar methodologies and various universal adhesives.