Vertical grooving: The newer paradigm of the postbonding reinforcement for fragment reattachment in uncomplicated crown fractures

Background: Vertical grooving has been proposed to overcome the concerns of refracture of fragments bonded using conventional simple reattachment protocol. However, the evidence related to its effectiveness is lacking. Hence, this study aimed to evaluate and compare the two protocols of vertical grooving for postbonding reinforcement of reattached fragments. Materials and Methods: Eighty bovine mandibular incisors were randomly allocated to four groups: intact tooth (Group I), simple reattachment (Group II), vertical groove with nonheated composite (Group III), and vertical groove with heated composite (Group IV). Fractures were simulated, fragments were reattached using standardized bonding procedures in Groups II, III, and IV, and reinforcement was performed via labial vertical grooves filled with either nonheated (Group-III) or preheated composite (50°C, 15 min) (Group-IV). All samples underwent thermocycling followed by the assessment of the force required to fracture using a universal testing machine. Results: Teeth reinforced with vertical grooves and nonheated composite (Group III) showed the highest median force required to fracture (183.39N), followed by Group IV (157.38 N). Both reinforcement protocols significantly increased the force required to fracture compared to simple reattachment ( P < 0.0001), although heating the composite led to a 14.2% reduction in this value. Conclusions: Vertical groove protocol with both nonheated and heated composite significantly increased the force required to fracture the reattached fragments in teeth with uncomplicated crown fractures, as compared to the simple reattachment protocol. While preheating the composite slightly reduced strength, it was still superior to the simple reattachment, suggesting its practical utility in the clinical settings.