Objectives: This investigation was designed to determine if Isotretinoin would affect expansion or relapse during palatal expansion therapy in a rat model.
Methods: Age and sex matched female (n=5) ~200g Sprague-Dawley rats were treated for 47 days with 2mg/kg/day of Isotretenoin IP (a dosage consistent with treatment of recalcitrant cystic acne in humans), or with DMSO vehicle as a control. Impressions of the maxilla were taken before spring placement. The palate was expanded approximately 1mm using stainless steel W-archwire springs bonded bilaterally to the molars delivering 10 gm force. The expansion was held for 4 weeks. Impressions were taken at debonding, and after 3 days and 7 days. The intermolar distance for each impression was digitally measured from photographic images of the impressions. Tissues were processed for histology at the last time point.
Results: Analysis with 2 sample t-test showed increased expansion of the palate between treated and untreated animals at debonding (1.20 vs 0.96mm respectively, p<0.03), and greater relapse at 3 day (0.46 vs 0.31mm, p<0.08) and 7 day (0.44 vs 0.27mm, p< 0.04) relapse periods.
Conclusions:
This study suggests that Isotretinoin may not hinder orthopedic or orthodontic expansion, but may increase the likelihood of relapse after palatal expansion.