Sealing ability of materials used as protective cervical barrier in internal tooth bleaching

Abstract

The use of a protective cervical barrier (PCB) is very well established to perform a safe internal bleaching; however, there is still no consensus on which material has the best sealing ability. Objective: This in vitro study aimed to evaluate the apical and linear sealing of different PCB materials placed during internal bleaching. Material and methods: This study had two study factors: PCB positioning, divided at two levels (cement-enamel junction [CEJ] and 1mm above the cement enamel junction [CEJ+1]); and PCB material, divided at eight levels (resin composite [RC], glass ionomer cement [GIC], resin-modified glass ionomer cement liner [LRGIC], restorative resin-modified glass ionomer cement [RRGIC], zinc phosphate cement [ZPC], eugenol-free zinc oxide cement [ZOC], provisional filling resin [PFR] and gutta-percha as control [GUT]). Response variables were apical and linear sealing obtained through dye penetration and analyzed with a digital microscope. Data were subjected to two-way analysis of variance followed by Tukey test (p<0.05). Results: The main factor for both apical and linear sealing was the type of material (p<0.01) regardless of their position. RC and ZPC presented the worst sealing values (p<0.05). The Spearman rank correlation coefficient revealed a positive correlation between the apical and linear leakage. Conclusion: The results suggest that RC and ZPC must be avoided as a PCB during internal bleaching procedures.