A comparative evaluation of fracture resistance using different techniques for the reattachment of fractured maxillary central incisor – an in vitro study

Objective To comparatively evaluate fracture resistance of different techniques for the reattachment of fractured maxillary central incisors. Materials and Methods Sixty intact freshly extracted permanent maxillary central incisors were selected and randomly divided into four groups of 15 each one of control (I) and three experimental groups (II, III, IV) according to the technique of reattachment. The incisal third of the experimental groups were sectioned horizontally. Group I: the teeth were kept intact without sectioning. Group II: an internal dentinal groove (1 mm deep and 1 mm wide). Group III: a pinhole (1.5 mm depth and 1.5 mm diameter). Fractured fragments in group II and group III were reattached using composite resin. Group IV: two vertical grooves (1 mm deep, 1 mm wide, and 4 mm length) with fiber-reinforced composite post (Everstick, GC America). After 24 h of restoration, all samples in each group were then subjected to thermocycling at 5±1 and 55±1°C for 500 cycles each cycle. All the samples were mounted on the universal testing machine (instron). The force was then applied at an angle of 45° of each tooth in a labial to palatal direction at a cross-head speed of 1 mm/min until fractured occurred and the obtained values were subjected to statistical analysis. Results The results showed that the mean fracture resistance of group I was the highest followed by group III, group IV, and group II the least (group II < group IV < group III < group I). Comparing the mean fracture resistance of four groups, analysis of variance showed significantly different fracture resistance among the groups (F = 22.93, P < 0.001). Conclusion No material and technique can restore the strength of intact tooth. However, reattachment techniques can be considered as an alternate method, when the fractured fragment is available with adequate size and appropriately preserved margins.