The influence of bruxism on post orthodontic direct anterior restorations integrity: a retrospective evaluation

The aim of this study was to evaluate the influence of bruxism on post orthodontic direct anterior restorations integrity.

In this retrospective study, adult subjects who received additive composite restorations in maxillary anterior teeth after an orthodontic treatment were recruited. Study group consisted of patients who reported fracture of the additive composite restorations, whereas controls were recruited among the patients who reported success, according to the modified United States Public Health Service (USPHS) criteria. A bruxism evaluation was performed according to the Standardized Tool for the Assessment of Bruxism (STAB). A Scanning Electron Microscopy evaluation was conducted to obtain a fractographic analysis.

A total of 40 restorations from 20 patients (8 males and 12 females, mean aged 25.67 ± 4.77 years) were evaluated. The following electromyographic variables resulted to be significantly different between groups: PC (p-value = 0.003), TC (p-value = 0.003), MC (p-value = 0.002), and TMC (p-value = 0.000). The fractographic analysis revealed that the fractures originated at the site of traumatic contact with the antagonist tooth.

At follow-up, patients with fractured anterior restorations showed significantly higher masseter muscle activity, evaluated in terms of phasic contractions, tonic contractions, mixed contractions, and total masseter contractions using a portable sEMG portable device. The fractographic analysis findings may be considered compatible with repetitive mechanical fatigue. The small sample size did not allow to draw robust conclusions. Future studies are needed on larger samples trying to identify the possible relationship between bruxism and anterior restorations fracture.