Post-Expansion and end of treatment outcomes of semi-rapid maxillary expansion with a modified removable appliance.

Context: Maxillary expansion is the mainstay therapy for maxillary transverse deficiency. There has been a constant search for the most effective yet biologically friendly method of maxillary expansion, alternatives being, slow, rapid and semi rapid.

Aims: The purpose of this study was to explore the outcome of palatal expansion achieved using a removable plate and low continuous forces brought about by a semi rapid screw activation protocol.

Settings And Design: Retrospective study.

Methods And Material: Plaster models of 56 consecutive patients treated for maxillary expansion were obtained pre-treatment (T), post-expansion (T), and post fixed appliance treatment (T). The radiographic images of the models were traced using Image J software. Linear and angular measurements were evaluated to measure transverse change.

Statistical Analysis Used: Interclass Correlation Coefficient [ICC] and Dahlberg's formula were used for reliability test. The differences in the mean values between the three duration groups [T, T and T] were analysed using Analysis of Variance (ANOVA). For multiple comparisons, a post hoc Tukey honestly significant difference (HSD) test was performed.

Results: Significant increase in inter-molar, alveolar and palatal linear widths were observed from T to T with significant relapses from T to T, with an overall net gain remaining at T. Similarly, significant increases in all angular measurements were observed from T to T with significant relapses from T to T and an overall insignificant change at T as compared to T.

Conclusion: The appliance and protocol were effective in producing transverse expansion with minimal molar and alveolar tipping.