Microleakage under polycarbonate and metallic brackets bonded with resin-modified glass ionomer versus light cured composite resin

Document Type : Original Article

Authors

1 Department of Orthodontics, faculty of dentistry, Alexandria University.

2 Department of Orthodontics ,faculty of dentistry, Alexandria University.

Abstract

Objective: An in vitro study to evaluate the microleakage at the occlusal and gingival margins of both polycarbonate and metallic brackets bonded with light-cured resin modified glass ionomer cement versus light cured composite.
Materials and Methods: 40 extracted sound premolars were divided into 2 groups. Group I was bonded with polycarbonate brackets (silkon M TM). 10 samples using light cure Fuji ortho (IA) and 10 samples using Trans bond XT (IB). Group II was bonded with metal brackets using both techniques (IIA&IIB). All samples were then subjected to thermo cycling. The root apices were sealed with sticky wax and the teeth were painted with 3 layers of nail polish leaving a 1mm window surrounding the bracket. Teeth were then immersed in 0.5% basic fuchsine dye solution for 24 hours at room temperature then washed under running water and sectioned longitudinally between the bracket wings into two halves using a low speed thin diamond disc under a stream of water. The extent of dye penetration was detected using a light stereomicroscope (x18 magnification) at both the occlusal and gingival areas of the brackets between both the enamel adhesive and the bracket adhesive interphases using soft imaging analysis. Descriptive statistics were computed as means and standard deviations of micro leakage values in different groups. Pooled micro leakage allowed the use of ANOVA, Tukey HSD test and the general linear model test at p<0.05. Significance level was set at 5%. Statistical analysis was done using SPSS version 17.Bar charts with Error bars were used for graphical presentation. Results: The gingival side of all groups exhibited higher microleakage compared with the occlusal side for both adhesive interfaces. All bracket and adhesive combinations displayed statistically significant differences in microleakage between the enamel-adhesive and adhesive-bracket interfaces at the occlusal and gingival sides of the brackets. When the adhesive systems were compared, the Resin Modified Glass Ionomer cement (RMGIA) showed more microleakage than the light cured composite resin between the different interfaces. The polycarbonate brackets with the addition of ceramic fillers showed more microleakage than metallic brackets. Conclusion: The overall comparison of the bonding system used revealed that no combination was found to be superior in their microleakage inhibition property, and polycarbonate brackets even by addition of ceramic fillers seemed that it was still inferior to the metallic brackets in the microleakage inhibition property.

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