Influence of Different Bonding Agents and Composite Resins on Fracture Resistance of Reattached Incisal Tooth Fragment

Statement of problem: reattachment of the fractured tooth fragment should be considered as a conservative treatment and valid alternative to a composite restoration. purpose: this in vitro study was to evaluate the influence of different adhesives and composite resins on fracture resistance of dental fragment reattached to the sectioned incisal edges. materials and method: 120 sound human maxillary central incisors were selected under standard conditions and randomly divided into 3 groups, 12 sound teeth were used as a control group and the remaining teeth were assigned to 3 groups (n=36) and each group into three subgroups (n=12). the incisal third of the samples was sectioned using a diamond disk and the respective fragments were then reattached utilizing different intermediate restorative materials, namely: i) adhesive materials alone (opti- bond s or optibond xtr or optibond all-in-one; ii) premise flowable composite and iii) point 4 composite in the one of the mentioned adhesive interface. after storage for two weeks at 37°c and 100% humidity and then thermocycling; shear bond strength (sbs) was recorded in kilogram force (kgf) by applying a load in the middle incisal third with a zwick universal testing machine at a cross-head speed of 1 mm/min. data was analyzed with one-way anova and tukey hsd (p< 0.05). results: the control group had a significantly higher sbs than other groups (p= 0.001); the highest sbs values were obtained using the premise flowable composite and optibond s adhesive (112.44±30.46 mpa); and the lowest with optibond all-in- one alone (33.97± 15.63 mpa). conclusion: although, none of the tested materials provided fracture resistance similar to that found with the intact maxillary central incisors; utilizing the premise flowable composite and optibond s adhesive improved the sbs of the reattached fragment than other materials.