Effect of methotrexate on the mandibular development of arthritic rabbits.

INTRODUCTION Juvenile idiopathic arthritis affecting the temporomandibular joint (TMJ) can cause severe disturbances of the mandibular development. Methotrexate (MTX) is often administered as a common used remission-inducing agent to treat this disease. The aim of this study was to investigate the effect of low dose MTX on the mandibular growth in arthritic rabbits. SUBJECTS AND METHODS Eighteen 10-week-old female New Zealand white rabbits were randomly assigned to three groups with six animals in each group. After being sensitized to ovalbumin (OA), the first and the second group received intra-articular injections with OA. The first group remained untreated, the second was treated by weekly injections of MTX. Cephalograms were taken from each animal at 10, 13, 16, 19, and 22 weeks of age and six mandibular distances measured. RESULTS All distances showed an increase between 10 and 20 per cent, whereas growth was more accentuated in the sagittal dimension. Significant differences in the overall growth could be observed between the arthritic and the control animals and less accentuated between the arthritic and the MTX animals. In contrast, existing differences between the groups were not significant during the intervals, but time had the greatest influence on mandibular growth. CONCLUSIONS MTX seems to have a positive impact on growth in rabbits suffering from experimental arthritis of the TMJ.