Assessment of the effects of different rapid maxillary expansion appliances on facial soft tissues with a three dimensional facial imaging technique

The purpose of this prospective study was to determine three dimensional (3D) effects of three different rapid maxillary expansion (RME) appliances on facial soft tissues. Forty-two children (18 males, 24 females) who required RME treatment were included in this study. Patients were randomly divided into three equal groups: Banded RME (mean age:12.7 years), acrylic splint RME (mean age:12.4 years) and modified acrylic splint RME (mean age:12.5 years). For each patient, 3D images were obtained before treatment (T1) and at the end of the three-month retention (T2) with 3dMD system. Linear, angular and volumetric analysis were made on the 3D photographs. For statistical analysis, the dependent sample t-test, and a one-way ANOVA test were used. When three RME appliances were compared to the effects on the facial soft tissues, there were no significant differences among them (p>0.05). The mouth width and nasal width showed a significant increase in all groups. Although the effect of the acrylic splint RME appliances on total face height was less than that of the banded RME, there was no significant difference between the appliances (p>0.05). The effect of the modified acrylic splint appliance on the upper lip was significant according to the volumetric measurements (p<0.01). There were no significant differences among the effects of three RME appliances on the facial soft tissues. Modified acrylic splint RME produced more protrusive effect on the upper lip. The changes in the facial soft tissues may be easily, reproducibly and efficiently measured with 3dMD face imaging system. Key words: Rapid maxillary expansion, Three dimensional imaging, Soft tissue, 3dMD, Face analysis