Photoelastic stress analysis of different types of anterior teeth splints.

BACKGROUND/AIMS Traumatic dental injuries are highly prevalent and are considered an important health problem. The aim of this study was to evaluate the in vitro stress distribution around simulated traumatized teeth subjected to different types of splints by photoelastic analysis. MATERIALS AND METHODS For each group, five models of maxillary and mandibular arches were made in photoelastic resin using prefabricated teeth models, which were fixed and adjusted in a semi-adjustable articulator. All splints were bonded with composite resin on the labial surfaces of the maxillary central incisors, the lateral incisors and the canine teeth, simulating trauma to the 11. The groups were divided according to the type of splint: control - without splint; rigid - brackets and 0.021x0.025 inch stainless steel wire; semi-rigid - brackets and 0.016x0.016 inch cobalt-chromium wire; fiber - fiberglass ribbon; and flexible - nylon thread. The groups were submitted to an occlusal force in a special device attached to a universal test machine in balanced, protrusive and lateral occlusions. Then, the incisal edge of the 11 was ground to simulate infra-occlusion, and the tests were performed again. Five points were analyzed around tooth 11 with a polariscope, and the data were submitted to ANOVA and Tukey tests at a 5% level of significance. RESULTS When centric occlusion was analyzed by comparing normal occlusion to infra-occlusion, all groups showed high stress values in infra-occlusion with statistical differences-except for the control group. When lateral occlusion was analyzed, the nylon splint showed lower statistical differences compared to the control, fiberglass and rigid splint groups, which did not differ between each other. The semi-rigid splint did not differ from any group. CONCLUSIONS Fiberglass and semi-rigid splints showed better stress distribution around the traumatized tooth under occlusal loads. The nylon splint showed characteristics of non-stress distribution.