Re-attachment of anterior fractured teeth: fracture strength using different materials.

This study compared the fracture strength of two different techniques (bonded only and buccal chamfer) and different material combinations used to reattach tooth fragments. An axial load applied to the buccal area fractured 110 sound permanent lower incisors. Fifty teeth were designated for the bonded only group (no additional preparation) and 50 teeth were designated for a buccal chamfer group. For each group teeth were subdivided into five subgroups (n = 10) according to the restorative material combinations used: 1) adhesive system (A); 2) A + light cured luting cement; 3) A + dual cured luting cement; 4) A + flowable resin and 5) A + hybrid resin. In a control group (resin composite build-up), in the remaining 10 teeth, the crown portion was rebuilt with adhesive and resin composite. Restored teeth were subjected to the same loading in the same buccal area. Fracture strength after restorative procedures for all groups was expressed as a percentage of the original fracture strength and the results were analyzed by two-way ANOVA and Tukey's test for pair-wise comparison. The interaction and the material factor were not statistically significant (p = 0.140 and p = 0.943, respectively). The chamfer group showed higher fracture strength recovery (67.9%) than the bonded only group (41.1%), and both were statistically lower than the resin composite build-up (103.2%). It was concluded that the material used to reattach the fragment is less important than the chosen technique.