Shear bond strength of a new low-shrinkage flowable composite for orthodontic bracket bonding

The purpose of this study was to determine the shear bond strength (SBS) and adhesive remnant index (ARI) value a new generation low-shrinkage flowable composite compared to a conventional bonding adhesive and several flowable composites.

One hundred and fifty sound human premolars extracted for orthodontic treatment were randomly divided into five groups of 30 teeth each. Brackets were bonded to the teeth in each group with a conventional bonding composite, three flowable composites, and a new generation flowable composite. SBS values of these brackets were recorded via an Instron testing machine. ARI scores were determined after the failure of brackets.

There was a statistically significant difference between flowable composites (P<.01). The mean bond strength for the conventional bonding composite group was significantly greater than that of each of the other four groups (P<.001). There were significant differences (chi-square=29.02; P=.00) among the groups.

The demineralization and microleakage-inhibiting effects and simple application of the new low polymerization shrinking flowable composite indicate that it might be considered for clinical use in orthodontic patients, especially those with inadequate oral hygiene.