Altogether 17 patients treated with arch bar splints fixed onto teeth were tested at the time of splint removal and approximately 5 months later. Patients were treated with intermaxillary fixation (IMF) because of either orthognathic surgery (7 patients) or mandibular fractures (10). The CPITN index was used for estimating the periodontal status, and tooth mobility was measured with Periotest. Seven patients in the orthognathic surgery group could also be examined before splinting. Periodontal status, as shown with relative proportions of various CPITN indexes, worsened due to splinting but regained its original level at control examination a minimum of 5 months after splint removal. Since the mean Periotest values did not differ between the first and control examinations in the seven patients undergoing orthognathic surgery, the analysis of the effect of splinting on tooth mobility was performed from the values obtained immediately after splint removal and at control visit. Splinting was shown to increase Periotest values more in female patients, in younger ones, and in those who were splinted for a shorter period. Teeth with the smallest roots showed greater differences in Periotest values than those with large roots, and the greatest differences in mobility were observed in incisors.