Effect of irradiance and exposure time on the adhesive properties of universal adhesives after 2 years of storage.

Clinical oral investigations 2023 Sep

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This study aims to evaluate the effects of exposure time and irradiance on the dentin bonding properties (microtensile bond strength (μTBS) and nanoleakage (NL)) of the Clearfil Universal Bond Quick (CUQ) adhesive and Scotchbond Universal Adhesive (SBU) immediately and after 2 years of water storage. Hence, 128 human molars were randomly assigned to 16 groups based on adhesive strategy, irradiance/exposure times, and storage time for each universal adhesive tested. The adhesives were applied using the etch-and-rinse and self-etch strategies and were light-cured using four different irradiance/exposure times: 1400 mW/cm2 for 5 s (1400 × 5), 1400 mW/cm2 for 10 s (1400 × 10), 3200 mW/cm2 for 5 s (3200 × 5), and 3200 mW/cm2 for 10 s (3200 × 10). Then, each sample was restored and sectioned into a resin-dentin bonded stick to be tested for μTBS and NL (immediately and after 2 years of water storage). The mean μTBS and NL of all resin-dentin bonded sticks from the same hemi-tooth (factor time) were statistically analyzed using a three-way ANOVA and Tukey's test (a = 0.05). Despite a significant decrease in the μTBS values for all groups after 2 years of water storage, the 3200 × 5 group showed higher μTBS values, whereas the 3200 × 10 group showed lower μTBS values for both universal adhesives tested. Although a significant increase in the NL values was observed for all groups after 2 years of water storage, the 3200 × 10 group showed higher NL values than the other groups (p < 0.001). Results indicate that light-curing the adhesive layer with 14-16 J/cm2 led to an improvement in the stability of the resin-dentin adhesive interface. A longer exposure time (10 s) coupled with a higher irradiance (3200 mW/cm2) resulted in a greater degree of degradation of the adhesive interface. To guarantee better stability of the adhesive interface, clinicians could be preferred a light-cured universal adhesive layer with 14-16 J/cm2. Higher irradiances should be avoided. © 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.

Citation

Karoline G B A Cavalcanti, Camilo Pulido, Pedro H A Moreira, Camila F Monteles, Byron L C Salvatierra, Fabiana S F Siqueira, Carlos J Soares, Alessandra Reis, Alessandro D Loguercio, Andres F M Cardenas. Effect of irradiance and exposure time on the adhesive properties of universal adhesives after 2 years of storage. Clinical oral investigations. 2023 Sep;27(9):5223-5232