A comparative assessment of changes in dental arches associated with different activation protocols of rapid maxillary expansion.

Aim The aim of this study is to compare dental arch changes associated with different activation protocols of maxillary expander. Materials and Methods A sample of 101 subjects with constricted maxillary arches (49 males and 52 females; mean age 10.96 +/- 1.91 years) was enrolled in the study. All subjects underwent RME with a stainless steel banded expander cemented to the maxillary first molars and the expansion screw was randomly activated with two different rapid maxillary expansion protocols (one-quarter per day or two quarters per day). The study also involved a control group of 22 subjects (10 females and 12 males, mean age 10.39 +/- 1.32 years) who underwent no treatment. A statistical comparison between the dental arch measures obtained before and after treatment in the two groups was performed. Results The Wilcoxon rank-sum test shows statistically significant differences of the measurement increases between the two activation protocols (at least p= 0.01). Statistically significant differences were also reported in comparison with the control group. Conclusions A taster activation protocol could be able to determine a greater anterior opening of the mid-palatal suture. Moreover, it seems to yield a higher width increase in the molar area.