Effect of three different conditioning agents on cavosurface microleakage and bond strength of glass ionomer restorations – An in vitro study

Abstract

Aim: This study aimed to investigate the conditioning effects of phosphoric acid/5.25% sodium hypochlorite (NaOCl) mixture, 2% chlorhexidine (CHX) digluconate, and 10% polyacrylic acid on cavosurface microleakage and bond strength of glass ionomer (GI) restorations. Materials and Methods: Out of 68 extracted premolars, 34 teeth were selected for microleakage and 34 for bond strength evaluation. The samples were divided into the following four groups. Group 1: pretreatment with 50/50 volume% mixture of 5.25% NaOCl solution and 37% phosphoric acid (H3PO4), Group 2:pretreatment with 2% CHX digluconate, Group 3: pretreatment with 10% polyacrylic acid (positive control), and Group 4: no pretreatment (negative control). All the samples were then restored with glass ionomer cement (GIC). Microleakage was evaluated using a stereomicroscope and rhodamine-B dye penetration test. For bond strength, flat dentin surface was exposed and pretreated as mentioned previously and restored with GIC and was evaluated using universal testing machine. Results: Among all the four groups, Group 1 showed least microleakage and highest bond strength when compared with other groups. Whereas the Group 4 samples which were not pretreated with any of the conditioning agent showed the least shear bond strength with greatest cavosurface microleakage when compared to the groups which were pretreated with the conditioning agents. Conclusions: A combination of 50/50 volume % mixture of 37% H3PO4 and 5.25% NaOCl can be a good choice for surface pretreatment of GI restorations.

Keywords

• deproteinization
• dye penetration
• microleakage
• shear bond strength
• smear layer