Effect of S-PRG containing coat on the shear bond strength and the prevention of enamel microcrack formation after orthodontic bracket removal: an invitro study.

Abstract

Among the most common complications after orthodontic treatment are enamel microcracks. These issues arise either from enamel demineralization or during bracket debonding or adhesive remnant removal after bracket removal; thus, the current investigation attempts to assess the impact of S-PRG comprising coat on the shear bond strength of the bonded resin composite and the prevention of enamel microcrack formation following orthodontic bracket removal. Fourteen sound, intact human premolars recently extracted were collected. A scanning electron microscope (SEM) was used to assess the enamel surface to exclude teeth with micro-cracks. The teeth were divided randomly into two groups (n = 7). In group 1 (control group), the metal bracket was bonded to the etched enamel with (Beauti-Bond xtreme, SHOFU, Japan) adhesive and a thin layer of (Beautifil II Giomer, SHOFU, Japan). In group 2 (intervention group), PRG BarrierCoat^® (SHOFU, Japan) was applied on the etched enamel prior to adhesive application. The teeth were then subjected to shear bond strength (SBS) testing using a universal testing machine. SEM and quantitative elemental analysis (weight%) by EDX spectrometry were performed by a calibrated examiner to all teeth to determine the enamel microcrack formation after debonding. The data were analyzed using Fisher's exact test, independent t-test and the point biserial correlation coefficient. The significance level was set at p < 0.05 within all tests. For SBS, Ca weight, and Ca/P, group (2) had significantly higher mean values than group (1). In contrast, the difference in P weight was not statistically significant. Additionally, the percentage of crack formation in group (1) was higher than that of group (2); however, the difference was not statistically significant. For Ca weight and Ca/P, there was a strong negative correlation with crack formation, with higher mean values significantly associated with the absence of cracks. For P weight, the correlation was not statistically significant. PRG BarrierCoat^® shows promise in enhancing shear bond strength with metal brackets. The high mineral content of PRG BarrierCoat^® enhances the integrity of enamel and helps in the prevention of microcrack formation. However, additional long-term clinical trials are required to confirm these findings under dynamic oral conditions.