Effect of collagen cross-linkers on micro tensile bond strength of total-etch adhesive to dentin

Purpose: To evaluate the efficiency of collagen cross-linkers on micro-tensile bond strength of total-etch adhesive with and without thermal cycling.
Materials and methods: The occlusal surfaces of twenty-four caries-free permanent human molars were ground flat to obtain a uniform surface free of enamel exposing the mid thickness of dentine. The prepared speciemens were randomly divided into four equal test groups according to the type of dentin pretreatment (n=6). Group I; control group: the exposed dentin did not receive additional treatment after acid etching. Group II; the etched dentin was treated with Gluma Desensitizer(GA). Group III; the specimens surface was painted with 5% glutaraldhyde solution (GD). Group IV; the specimen surface was painted with 15% proanthocyanidin (PA). Single Bond Universal adhesive was applied to the dentin surface of all the test groups and the dentin specimens were restored with resin composite. The specimens were sectioned to obtain beams of 0.9±0.1 mm in thickness and 5.5±1 mm in length and half of the resultant beams of each group were subjected to thermo cycling. Tensile load was applied until bonding failure of the specimen occurred and micro tensile bond strength was calculated in Mega Pascal. Comparison between all test groups was done using One Way ANOVA followed with Tukey’s post hoc test when the ANOVA test was significant. p value was ≤0.5. Comparison between the thermocycled and none thermocycled groups was done using unpaired student t test.
Results: The highest statistically significant microtensile bond strength values were found in the Gluma and GD surface pretreated groups, with no statistical significant difference between them. The lower micro tensile bond strength values were found in the control and PA groups with no significant difference between them, while thermocycling did not decrease the microtensile strength values of the PA group.
Conclusions:1-Gluma and glutaraldehyde used as cross-linkers increased the microtensile bond strength of dental adhesive to dentin and maintain collagen stability with thermocycling. 2-The PA cross-linkers did not improve microtensile bond strength but maintain bond stability with thermocycling increasing the longevity of the adhesive bond.