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

Abstract

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. 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 (1mm/min-1 ). Data were submitted to two-way analysis of variance and post hoc Tukey test (5%). 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 (15minutes or 24hours). Rehydrating a tooth fragment for 15minutes before bonding with a multimode adhesive maintained sufficient moisture to increase reattachment strength.