Effect of incisal tooth wear and restoration on interocclusal distance during Brazilian Portuguese language speech.

AIM The aim of this study was to investigate changes in interocclusal distance (IOD) during pronunciation of /m/ and /s/ sounds in Brazilian Portuguese, in patients presenting dental wear due to bruxism, before and after placement of a stabilization appliance and restorative treatment. METHODS Subjects were divided into a control group of 19 patients with no dental wear and an experimental group of 18 patients presenting dental wear on anterior teeth due to bruxism. A stabilization appliance was placed in each patient in the experimental group and anterior teeth were restored. A magnetic jaw-tracking device measured the interocclusal distance during pronunciation of /m/ and /s/ phonemes. Interocclusal distance for the experimental group was evaluated one week before and again immediately before the appliance was inserted and 24 hours, 7 days, 1 month and 2 months after appliance insertion. The same evaluation was performed 7 days and 1 month after restorative treatment. In the control group, the measurements were carried out at the same intervals. RESULTS Comparison between groups revealed a significant difference (P<0.05) in interocclusal distance for the /m/ sound at all evaluation intervals. No differences were found before and after appliance insertion and restorative treatment with either phoneme. CONCLUSION Stabilization appliance therapy and restorative treatment of subjects with dental wear did not change the interocclusal distance during speech of /m/ and /s/ sounds in the Brazilian Portuguese language, however, when compared with normal subjects, the IOD values were higher for the dental wear group during pronunciation of the /m/ sound.