Comparative Evaluation of Two Post-Bonding Reinforcement Protocols for Fragment Reattachment in Uncomplicated Crown Fracture-An In Vitro Study.

Abstract

Background/aims: Re-bonding of a fractured fragment without any preparations or reinforcement has been recommended as the preferred treatment of uncomplicated crown fractures. A recent systematic review found that post-bonding reinforcements could reduce the risk of loss of attached fragments in teeth with uncomplicated and complicated crown fractures. Hence, this study aimed to compare various techniques of reinforcement in terms of the force required to fracture, using bovine incisor models with simulated uncomplicated crown fractures.

Methods: This in vitro study was initiated after obtaining approval from the Institutional Ethics Committee. The sample size was calculated as 20 teeth per group, and bovine mandibular incisors were carefully evaluated for size and absence of structural defects and randomly allocated to four groups (Group I- Simple Reattachment, Group II- External Chamfer, Group III- Over contouring, Group IV- Sound teeth). Those in experimental groups were subjected to a fracture protocol, kept dry at room temperature and atmospheric pressure for 24 h, rehydrated for 15 min, and bonded using simple reattachment. The post-bonding reinforcement protocols were followed for Groups II and III. Samples were stored in normal saline, and thermocycling was performed. A universal testing machine was used to assess the force required to fracture.

Results: The least magnitude of force required for fracture was seen in Group I, while the highest was seen in Group III (164.75 N). The force in Group I was significantly lower compared to all the protocols of post-bonding reinforcement and the control teeth (Group IV). A statistically significant difference was not seen between Groups II and III.

Conclusion: The force required to fracture the teeth subjected to post-bonding reinforcement was significantly more than that seen after simple reattachment. The maximum force was exhibited by the teeth reinforced by over-contouring, followed by an external chamfer.