comparison of microtensile bond strength of silorane-based composite with the conventional methacrylate composite to the dentin of primary teeth

statement of problem: the bond strength between restorative material and tooth structure is so important for conduction of durable restoration. considering the recent attention to low shrinkage composite resins, evaluation of micro tensile bond strength of these materials would be valuable. objectives: to compare the microtensile bond strength of silorane composite resin (filtek p90) with the conventional methacrylate composite (filtek z250) with and without applying acid etch before application of bonding system. materials and methods: in this experimental study, 24 intact primary canines were used. after the dentin was exposed, the teeth were randomly divided into four groups as follows: the first group (silorane bond system + composite filtek p90); the second group (etch + silorane bond system + composite filtek p90); the third group (single bond + composite filtek z250); and the fourth group (etch + single bond + composite filtek z250). the teeth were cut on the longitudinal axis and the interface between the composite and dentin were grinded buccolingually and mesiodistally. the samples were subjected to a microtensile force until breakage. the obtained values were recorded in mpa; data were analyzed using one-way anova and tamhane’s t2 statistical tests. results: the average microtensile bond strength in all groups had a statistically significant difference with each other (all p < 0.05). the highest bond strength belonged  to  the  second  group  (etch  +  silorane  bond  system  +  composite filtek p90) and the lowest value was related to the third group (single bond + composite filtek z250). conclusions: as the second group (etch + silorane bond system + composite filtek p90) exhibited higher microtensile bond strength, it may prove that using composite filtek p90 is preferable to be used in primary dentin in comparison with composite filtek z250, and using etch + silorane bond system is more advantageous than single bond system.