AIM: The aim of this study was to investigate the influence of different bleaching procedures (including the violet LED lamp) on microshear bond strength (SBS) and on dentinal matrix-matalloproteinase (MMPs) activity. METHODS: The middle dentin of extracted human molars (n=8) was exposed and were embedded in self-curing acrylic resin leaving one surface available for adhesion. Four groups were formed according to the bleaching procedures: 1)35% hydrogen peroxide gel 4x20min (HP35%; Opalescence Endo, Ultradent); 2)violet LED lamp 4x20min (VL; Bright Max Whitening, MMOptics); 3)hybrid technique-4x20min VL+4x4min HP35% (HYB); 4)no bleaching (CTRL). Half of the specimens were restored immediately (T0) using a universal adhesive (Futurabond U, Voco) in self-etch (SE) or etch-and-rinse mode (ER) and a resin composite (cylinder designated molds 2.5x3 mm), while the remaining half after 2 weeks of storage humid conditions (T2). At T0 and T2, SBS test was performed. The same bleaching procedures were performed on additional teeth (n=3) that were processed to evaluate the MMPs activity using in situ zymography at T0 and T2. Data were statistically analyzed (p<0.05). RESULTS: HYB group demonstrated higher bond strength values compared to all the other groups in ER mode and compared to VL in SE mode (p<0.05), and was not affected by aging (p>0.05). While HP35% decreased bond strength at baseline compared to CTRL (p=0.033), this effect was reversed after 2 weeks (HP35>CTR, p<0.001). This was partially in accordance with MMPs activity results, since HYB resulted in lower, and HP35% group in higher activity compared to CTRL (p<0.05). However, MMPs activity was lower at T2 than T0 (p<0.05) except for HP35% and HYB, where enzyme activity still increased after 2 weeks (p<0.05). CONCLUSION: As to achieve the best stability of a restoration after bleaching treatment regardless of the adhesive strategy, the Hybrid bleaching procedure seems to be the protocol of choice.
Florenzano, F., Maravic, T., D'Alessandro, C., Josic, U., Mazzitelli, C., Mayer-Santos, E., et al. (2024). Bleaching procedures influence on dentin bond strength and enzymatic activity.
Bleaching procedures influence on dentin bond strength and enzymatic activity
florenzano
Primo
;maravic T.;D'Alessandro C.;Josic U.;Mazzitelli C.;Mancuso E.;Breschi L.;Mazzoni A.
2024
Abstract
AIM: The aim of this study was to investigate the influence of different bleaching procedures (including the violet LED lamp) on microshear bond strength (SBS) and on dentinal matrix-matalloproteinase (MMPs) activity. METHODS: The middle dentin of extracted human molars (n=8) was exposed and were embedded in self-curing acrylic resin leaving one surface available for adhesion. Four groups were formed according to the bleaching procedures: 1)35% hydrogen peroxide gel 4x20min (HP35%; Opalescence Endo, Ultradent); 2)violet LED lamp 4x20min (VL; Bright Max Whitening, MMOptics); 3)hybrid technique-4x20min VL+4x4min HP35% (HYB); 4)no bleaching (CTRL). Half of the specimens were restored immediately (T0) using a universal adhesive (Futurabond U, Voco) in self-etch (SE) or etch-and-rinse mode (ER) and a resin composite (cylinder designated molds 2.5x3 mm), while the remaining half after 2 weeks of storage humid conditions (T2). At T0 and T2, SBS test was performed. The same bleaching procedures were performed on additional teeth (n=3) that were processed to evaluate the MMPs activity using in situ zymography at T0 and T2. Data were statistically analyzed (p<0.05). RESULTS: HYB group demonstrated higher bond strength values compared to all the other groups in ER mode and compared to VL in SE mode (p<0.05), and was not affected by aging (p>0.05). While HP35% decreased bond strength at baseline compared to CTRL (p=0.033), this effect was reversed after 2 weeks (HP35>CTR, p<0.001). This was partially in accordance with MMPs activity results, since HYB resulted in lower, and HP35% group in higher activity compared to CTRL (p<0.05). However, MMPs activity was lower at T2 than T0 (p<0.05) except for HP35% and HYB, where enzyme activity still increased after 2 weeks (p<0.05). CONCLUSION: As to achieve the best stability of a restoration after bleaching treatment regardless of the adhesive strategy, the Hybrid bleaching procedure seems to be the protocol of choice.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
