Rapid maxillary expansion effects on dynamic measurement of natural head position

Objective: To identify the effect of rapid maxillary expansion (RME) procedure on dynamic
measurement of natural head position (NHP).
Materials and Methods: The treatment group comprised 23 patients, 12 girls and 11 boys (mean
age: 10.1 6 1.1 years), and the control group comprised 15 subjects, 8 girls and 7 boys (mean age:
9.7 6 1.4 years). The test subjects underwent RME treatment using full cap acrylic device, and the
mean amount of expansion was 5.48 mm. An inclinometer and a portable data logger were used to
collect the NHP data. Intragroup changes were evaluated by using nonparametric Wilcoxon test,
and intergroup changes were analyzed with Mann-Whitney U-test. P values less than .05 were
considered statistically significant.
Results: The mean difference between initial and final NHP was 0.31u, and this difference was not
statistically significant. Also, there were no statistically significant differences between the RME
and control groups before and after treatment.
Conclusion: Treatment with the RME procedure showed no statistically significant effects on
dynamic measurement of NHP when compared with initial values or untreated control.