SURGICALLY ASSISTED RAPID PALATAL EXPANSION VS SEGMENTAL LE FORT I OSTEOTOMY: TRANSVERSE STABILITY OVER A 2 YEAR PERIOD

INTRODUCTION: We compared the long-term stability of surgically assisted rapid palatal expansion (SARPE) and segmental Le Fort I osteotomy (bipartition) for expanding the maxillae in adult patients. METHODS: The upper jaw plaster models of 10 patients who underwent transverse expansion of the maxillae using the SARPE technique and 10 patients who underwent Le Fort I bipartition were examined. For each patient, the intercanine and intermolar distances before expansion (T1), after expansion (T2), and 2 years after expansion (T3) were measured. Consequently, we could evaluate the degree of expansion (between T1 and T2) and the relapse distance after 2 years (between T2 and T3). The palatal stability (i.e., extent of relapse) was used to assess the outcomes in both methods. RESULTS: In the SARPE group, the average increase in the intercanine and intermolar distance was +8.5 and +7mm, respectively. In the Le Fort I bipartition group, the average respective increase was +2.75 and +3.75mm. Two years after expansion, in the SARPE group, the intercanine distance decreased by 2.5mm or 28% of the overall expansion, and the intermolar distance decreased by 3.0mm or 36% of the overall expansion. In the Le Fort I bipartition group, the intercanine distance decreased by 0.25mm or 25% of the overall expansion, and the intermolar distance decreased by 0.75mm or 20% of the overall expansion. CONCLUSIONS: In the patients that we assessed, there was a high relapse rate in the mean intercanine and intermolar distances 2 years following the expansion. The overall relapse rate was more pronounced in the SARPE patients, whereas the Le Fort I bipartition technique was more stable, especially in terms of the intermolar distance.