Abstract: PURPOSE: The aim of the study was to investigate the dental changes of patients with obstructive sleep apnea hypopnea syndrome (OSAHS) with long-term treatment of oral appliances, via the method of three-dimensional model analysis. METHODS: Using Geomagic Studio 2014 software, we transferred the dental models, which were from 18 OSAHS patients before and after treatment of oral appliances, into three-dimensional models for digital analysis. Datasets obtained from pre- and after treatment were compared for accuracy via paired t test using SPSS 22.0 software package. RESULTS: Eighteen patients using oral appliances for 6.57±1.98 years, showed significant differences in some dentition values between pre-treatment and after-treatment. The total dentition changes indicated intrusion of upper premolars, buccalization of upper posterior teeth and mesialization of lower posterior teeth. Statistical analysis demonstrated decrease in upper dental arch length, increase in upper posterior arch width and decrease in upper arch depth and dramatic reduction of overjet in anterior teeth. In the same time, other values evaluated showed no significant change before and after treatment of oral appliances. CONCLUSIONS: Long-term wearing oral appliances results in changes in several variables of dental occlusion, which should not be ignored for dentists conducting this treatment plan. However, the side effect of dental occlusion changes is little on a whole, leading to high security in this aspect.

Key words: OSAHS, Three-dimensional model, Dental occlusion