Date of Award

Summer 2014

Document Type


Degree Name

Master of Science (MS)



First Advisor

Bradley, Thomas G.

Second Advisor


Third Advisor

Lobb, William


Introduction: Orthodontic treatment demands excellent outcomes in both function and esthetics. Despite the popularity of rapid palatal expansion in orthodontic treatment, few studies have examined its consequences on facial soft tissue using direct anthropometric measurements. The primary goal of this study was to determine facial soft tissue changes immediately following rapid palatal expansion. Materials and Methods: Twenty-eight patients (age range, 8-17 years) attending Marquette Dental School Orthodontic Post-Graduate Clinic were enrolled in the study. Facial soft tissue measurements were taken with digital calipers at two separate time points (T0: initial exam and T1: thirty days following expansion); measurements were recorded with patients sitting in the orthodontic chair in centric occlusion, with Frankfurt Horizontal plane parallel to the floor, and observing a relaxed-lip posture. One examiner took 18 measurements at two different time points (T0 and T1), and was blinded from the initial reading when the second round of measurements were taken. Descriptive statistics were performed and a paired t-test was used to compare measurements taken at the two time points. Regressions models were also conducted to determine the influence of age on the results. Results: Pearson's correlation coefficient, was found to be r = 0.998. This indicates nearly a one-to-one correspondence in the measurements taken at the two time points by the same examiner. Between the two time points, there was a statistically significant difference in intraorbital width, alar nasal width-widest nostrils, mouth width and soft tissue nasion at the tip of nose (p < 0.001). Anatomical structures closest to the facial midline appear to be most affected. Statistically significant increase included mouth width, nasal width, orbital width and the length of the soft tissue nose from nasion to the tip of the nose. All points that showed significant differences were directly related to rapid palatal expansion and were independent of age as determined via regression modeling. Conclusions: This study demonstrated that from a frontal perspective, rapid palatal expansion results in statistically significant facial soft tissue changes. Further assessment is needed to determine if these values are of clinical significance.