[Effects of orthodontic expansion of the mandibular arch on the periodontal condition of the posterior teeth].

In the present study we examined the long term influence of orthodontic mandibular arch expansion therapy on the periodontal condition of the posterior teeth. 11 years after the end of treatment 31 former patients of our clinic were compared with a control group of matched age and sex distribution. Although we found some additional loss of periodontal attachment for the treated group this differences were not considered to be of clinical significance. Within the treated group the stability of the orthodontic treatment result seemed to be correlated with more favourable periodontal conditions.