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The article provides information on aspects related to use of three dimensional imaging to study impact of maxillary expansion on facial soft tissues. Topics discussed include scanning of dentistry using cone beam computed tomography (CBCT), determination of soft tissue effects on facial movements, and crowns.

Objective: To test the hypothesis that there is no difference in the number of occlusal contacts in centric occlusion in patients treated with bonded and removable retention procedures and a control group during a 1-year retention period. Materials and Methods: Twenty-five patients received a removable Hawley retainer, and 25 patients received maxillary and mandibular bonded retainers. The retainer patients were compared with 20 control subjects with normal occlusions. Silicone-based impression bites were used to record occlusal contacts. Paired-sample t-test, analysis of variance (ANOVA), and Tukey tests were used to evaluate intragroup and intergroup differences. Results: An increased number of occiusal contacts were recorded in total-arch and posterior combined (actual/near) teeth during the retention period as compared with the control group. In the Hawley group, actual and total contacts on the first and second molar and actual contacts on the premolar and canine showed statistically significant increases. In the bonded retainer group, near and total contacts on the first and second molars and premolars showed statistically significant increases. Slight occiusal changes were seen in the control sample during the observation period, presumably from growth and development. ANOVA comparisons of total contacts of anterior and posterior teeth indicated statistically significant differences in the three groups on posterior segments. Conclusions: The hypothesis is rejected. Both retention procedures allowed relative vertical movement of the posterior teeth, but the number of contacts on the posterior segment was increased more in the bonded retainer group than in the Hawley and control groups at the end of retention. [ABSTRACT FROM AUTHOR]

Objective: To determine three-dimensional (3D) effects of three different rapid maxillary expansion (RME) appliances on facial soft tissues., Materials and Methods: Forty-two children (18 boys, 24 girls) who required RME treatment were included in this study. Patients were randomly divided into three equal groups: banded RME, acrylic splint RME, and modified acrylic splint RME. For each patient, 3D images were obtained before treatment (T1) and at the end of the 3-month retention (T2) with the 3dMD system., Results: When three RME appliances were compared in terms of the effects on the facial soft tissues, there were no significant differences among them. The mouth 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. The effect of the modified acrylic splint appliance on the upper lip was significant according to the volumetric measurements (P < .01)., Conclusions: There were no significant differences among three RME appliances on the facial soft tissues. The modified acrylic splint RME produced a more protrusive effect on the upper lip.