Is it necessary to pre-treat Dentine before GIC Restorations? Evidence from an in Vitro Study.

Abstract

The aim of this study was to assess the influence of different pre-treatment approaches on glass ionomer cement (GIC) bond strength (BS) to dentine. Sixty bovine incisors were allocated into six groups according to substrate - sound or caries-affected dentine; and substrate pre-treatment approach - no conditioning (control), polyacrylic acid for 10 s and phosphoric acid for 7 s. Teeth in the caries-affected dentine group were previously submitted to cariogenic pH-cycling challenge. After dentine pre-treatment, according to experimental groups, polyethylene tubes were placed on flat dentine surfaces and filled with GIC. Teeth were stored in distilled water for 24 h at 37 °C and then submitted to microshear test (0.5 mm/min). Failure pattern analysis was performed under stereomicroscope (400x). Data were analysed using two-way ANOVA and Tukey's test (α=5%). Statistically significant differences were found for the pre-treatment approach, regardless of substrate (p<0.001). The polyacrylic acid group and control group had similar BS values, and were both better than the phosphoric acid group. In general, GIC had better bonding performance in sound dentine than in caries-affected dentine. In conclusion, dentine pre-treatment with polyacrylic acid did not improve the performance of GIC restoration on clinically relevant substrates.

Phytic Acid: A Novel Dentine Conditioning Agent for Glass Ionomer Cement Restorations: An In Vitro Scanning Electron Microscopic Study

“…Strong acids administered as conditioners, on the other hand, have been shown to produce enamel and dentine decalcification, reducing the amount of calcium available for adequate adhesion and resulting in decrease of bond strength. [ 3 , 4 ] In light of these circumstances, an alternate agent was explored, and it was observed that phytic acid (IP6) was more biocompatible and non-cytotoxic than the routinely used EDTA. It has the ability to remove the smear layer from instrumented root canals and flat coronal dentin surfaces.…”

“…[ 6 ] As a result, numerous surface treatment agents to remove the smear layer before applying GIC have been proposed to incapacitate the impact of the smear layer and enhance bonding. [ 3 ] Although IP6 has been employed as an emergent endodontic irrigant/chelating agent capable of removing the smear layer, there is a paucity of information on the IP6 spectrum as a dentin conditioner. [ 5 ]…”