Comparison of fracture resistance in reattached anterior teeth using porcelain, composite and metal laminates

Fractured crown is one of the most prevalent dental problems. Dental researchers and clinicians are trying to find the most effective reattachment technique in order to provide adequate resistance as close to intact human tooth as possible. The purpose of this study was to investigate the effects of using porcelain, composite and metal laminates on fracture resistance of the re-attached coronal fragments in human anterior teeth. This in-vivo study was conducted using forty recently extracted human lower incisors. Samples were randomly assigned into four groups. Ten teeth with no prior preparations were selected as the control group. The rest of teeth were sectioned mesiodistally, four mm under and parallel to the incisal edge. These specimens were randomly assigned to three groups. Re-attachment was performed using single bond and flowable composite in all test groups according to manufacturer’s instructions. In porcelain laminate (PL) group, veneer preparations were made for buccal surface (window preparation). Composite and metal laminate preparations were made in lingual surfaces of the teeth in composite laminate (CL) and metal laminate (ML) groups. After impression taking and laboratory process, all laminates were cemented using resin cement. All teeth were mounted in self cured acrylic blocks and kept in saline solution. Using a testing machine, fracture procedures were performed in a cross-head speed of 0.5 mm/minute. The tooth inclination for testing were set at 135° angle before the loading blade and kept it in this position until fracture occurred. Differences between four groups were determined using one way analysis of variance (ANOVA) at 0.05 significance level. The mean fracture resistant in control, CL, PL and ML groups were 438.85 (±147.14), 420.05 (±109.59), 364.92 (±230.02)and 345.01 (±148.87) respectively. This analysis showed that, group differences were not statistically significant (P>0.05). Although composite laminate (CL) showed highest fracture resistance after the control group, but all the three techniques can be applied depending on the teeth and patient’s preferences.