Effect of dehydration and rehydration intervals on fracture resistance of reattached tooth fragments using a multimode adhesive.

BACKGROUND/AIMS: The tooth fragment bonding technique, frequently used to restore traumatized teeth, may be affected by dehydration/rehydration periods. The aim of this study was to evaluate the effects of different dry and wet storage intervals on multimode adhesive bonding between reattached fragments and teeth.

MATERIALS AND METHODS: Eighty-four bovine incisors were fractured and randomized into groups (n=12). After teeth fracturing, each specimen was assigned to one of the following groups: G0: control group (sound tooth); GA1 and GA2: 1-h dehydration and a 15-min or 24-hours rewetting period, respectively; GB1 and GB2: 24-hours dehydration and a 15-minutes or 24-hours rewetting period, respectively; and GC: 1-hour (GC1) or 24-hours (GC2) dehydration period only. Tooth fragments were then reattached using a multimode adhesive in a self-mode technique with a flowable resin composite. The fracture resistance was evaluated in a universal testing machine under a compressive load (1 mm/min-1 ). Data were submitted to two-way analysis of variance and post hoc Tukey test (5%).

RESULTS: No significant interaction between dehydration and rehydration intervals was observed (P>.05). Only the step of rehydration significantly affected the reattachment strength when compared to the groups submitted only to dehydration, regardless of the interval (15 minutes or 24 hours).

CONCLUSION: Rehydrating a tooth fragment for 15 minutes before bonding with a multimode adhesive maintained sufficient moisture to increase reattachment strength.