Effect of surface treatments on shear-bond strength of glass-ionomer cements to silver diammine-fluoride treated simulated carious dentine / Koh Wen Thong

Koh , Wen Thong (2024) Effect of surface treatments on shear-bond strength of glass-ionomer cements to silver diammine-fluoride treated simulated carious dentine / Koh Wen Thong. Masters thesis, Universiti Malaya.

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Abstract

Objectives: This study investigated the effect of different surface treatments on the shear-bond strength (SBS) and failure modes of high-viscosity glass-ionomer cements (HVGIC) and resin-modified glass-ionomer cements (RMGIC) to silver-diamminefluoride (SDF)-treated simulated carious dentine (SCD). Material and Methods: One hundred and fifty extracted human premolars were sectioned and pH-cycled for ten days to simulate carious dentine. In Part A, the demineralised specimens were treated with 38% SDF (Riva Star) for 2 mins, washed, stored in deionised distilled water at 37°C for two weeks, and subjected to the following surface treatments (n=14): T1 - no treatment (control); T2 - 10 seconds polyacrylic acid (PAA); T3 - 5 seconds phosphoric acid (PPA); T4 - 5 seconds PPA plus universal adhesive (Zipbond); T5 - 5 seconds PPA plus RMGIC adhesive (Riva bond LC). High Viscosity Glass-ionomer Cements (Riva Self-cure HV [SC]) and RMGIC (Riva Lightcure HV [LC]) restoratives were applied to the conditioned specimens and stored in artificial saliva at 37°C for one week. SBS was subsequently performed with a Universal Testing Machine (a load of 500N and crosshead speed of 1mm/min). Failure modes were appraised using a stereomicroscope coupled with the ImageJ software. Statistical analysis was done with Kruskal-Wallis/ post hoc pairwise comparisons (α=.05) and Chi-square tests with Bonferroni adjustment (α=0.05). In Part B, the interface between the HVGIC and dentine (n=1) was carried out using scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDX). Results: In part A, the highest SBS was observed when SC and LC were restored with T2 and T5, respectively. Significant differences in SBS were as followed: SC - T2, T1 >T5, T3; LC - T5, T4, T3 > T2. For T3 and T5, SBS achieved with LC was significantly greater than SC. SC generally exhibited adhesive failures. Conversely, LC exhibited mostly adhesive and mixed failure in the material for most surface treatments. In part B, The SEM demonstrated smooth and continuous layer of adhesive in the SC group. The presence of a short and discrete resin tag was seen with thin hybrid layer in phosphoric acid-treated LC groups. The EDX data demonstrated that there were detected fluoride and silver ions levels in all groups. In LC-T5, it was reported that the content of Ag is highly detected (3.30 at%) on the dentinal surface. Conclusion: The preferred method for surface-treating SDF-treated simulated carious dentine before restoration application is PAA for SC and PPA plus RMGIC adhesive for LC.

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