Acne Medication, Isotretenoin, Affects Tooth Movement in Rats

Objectives: A side effect of Isotretinoin, a drug used for resistant cystic acne, is osteopetrosis that can last years. In this animal study, its effect on sutural expansion and associated tipping and translation tooth movements was investigated.
Methods: Twenty-four juvenile Sprague-Dawley female rats were divided into treatment or control groups. The drug was administered before expansion to therapeutic levels and continued to the end of the experiment. CBCT scans were taken at spring placement (T1) to expand the maxilla laterally. After 3 weeks appliance was removed and CBCT scans taken (T2). Scans were repeated after 4 days of relapse (T3). Resulting coronal sections were analyzed for linear and angular parameters using the Anton-Bass analysis in Dolphin Imaging software between T2 and T1 (expansion) and T3 and T2 (relapse).
Results: There was significant hindrance to dental tipping of upper and lower molars while maxillary width and upper interdental widths were unaffected. Horizontal palatal width and nasal width were reduced, but did not achieve statistical significance. Expansion occurred through bodily buccal tooth movement. This resulted in increased incidence of buccal crossbite and dehiscence. Relapse of molar tipping was significantly less in the experimental group in both arches at 4 days. The upper relapse was 51% in the control group and half that in treated animals.
Conclusions: This animal study suggests that orthodontists query patients on Accutane use and watch for gum recession, expect increased treatment times, and disturbances in palatal expansion. It also suggests that the mechanism of action though broad-based, is targeted at periodontally-mediated dental tipping more than translation or sutural growth or expansion. This study also presents a successful animal model for testing drug effects on three types of orthodontic movements, dental tipping, sutural expansion and translation of teeth through the alveolus.