Microleakage of Two-Adhesive Systems after Na-ascorbate on Non-vital Bleached Teeth

Objectives:

The purpose of this study was to evaluate the effect of Na-ascorbate on microleakage interface tooth/ composite resin when submitted to nonvital tooth bleaching.

Methods:

One hundred human root filled incisor teeth were used in this study. Standardized cavities were prepared including enamel edge. The teeth assigned to 10 groups (n=10). 40 teeth bleached with office bleaching system (35% HP Opalescence extra) then were divided into two subgroups bonded with self and total etch system (Single Bond (SB), Clearfil SE (CSE) ) 40 teeth bleached with walking bleaching system (Na-perborate+H₂O₂) then were divided into two subgroups bonded with self and total etch system ((SB), (CSE)). 20 teeth were bonded with self and total etch system ((SB), (CSE) ) as a control. The teeth were immersed in distilled water at 37 C degrees for 24 hours. Microleakage was assessed by dye penetration.  Teeth were sectioned from buccal to lingual, through the centre of the restoration, using a diamond disk. Leakage was assessed using scores from 0 to 3 under magnification (x20). Data were analyzed by Kruskal-Wallis and Mann-Whitney tests (p> 0.05). Microleakage scores (means ± S.D., n=10 for each group) were summarized in the table below.

Results: The results showed that there are no significant differences at self etch groups. Sodium perborate+H₂O₂  with Na-ascorbate  significantly increase the microleakage in composite restoration

Means marked by the same letters are not significantly different.

Conclusion: This presented study exhibited that there is no effect of bleaching treatment on microleakage of self-etching bonding. However, Na-ascorbate increased the microleakage of sodium perborate+H₂O₂  group  when a total-etching bonding agent was used.