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Abstract

Context: Bowen developed Bis-GMA monomer in an attempt to improve physical properties of acrylic resins. Urge for change in properties and filler size has led to development of a new composite resin characterized by nano particles. Improvements in composite resin were accomplished by altering filler levels which helped in reducing polymerization shrinkage. In view of developments in bonding this in vitro study was aimed. Aims: To evaluate and compare three adhesive resins, Transbond XT †, Fuji-Ortho-LC ᵜ and Filtek Z 350 ♦ for their comparative strengths before and after subjecting these materials to a caries producing solution for 2 hours / day for a period of 30 days. Settings and Design: 180 sound premolars were divided into 2 broad groups of 90 teeth each, control group were exposed to artificial saliva solution for a period of 30 days, whereas, experimental group were exposed to artificial saliva and two hours of exposure to caries producing solution. These groups were subdivided into six subgroups of 30 teeth each. After a period of 30 days, shear bond strength tests were carried out using Universal Testing Machine. Bond failure was assessed by Adhesive Remnant Index and bracket base were examined under stereomicroscope using 10 X magnification. Results: Nano ceramic restorative material (Filtek Z 350 TM♦3M) had lower bond strength when compared to Conventional orthodontic composite (Transbond XTTM † 3M) and Resin Modified glass ionomer Cement (Fuji-Ortho-LC TMᵜ). Analysis of variance (two way ANOVA) (p <0.05) and Tukey's HSD Post-hoc test (p < 0.05) indicated significant differences between these materials. When Adhesive Remnant Index was evaluated it was seen that majority of groups showed score of 0 and 1. Conclusions: Subjecting teeth to demineralization solution did not alter bond strength to statistically significant values. No specimens tested showed failure site at adhesive-bracket interface.