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Clinical Paper Orthognathic SurgerySkeletal and dental stability of segmental distraction of the anterior mandibular alveolar process. A 2-year follow-up Abstract. 33 patients (27 females; 6 males) were retrospectively analysed for skeletal and dental relapse before distraction osteogenesis (DOG) of the mandibular anterior alveolar process at T1 (17.0 days), after DOG at T2 (mean 6.5 days), at T3 (mean 24.4 days), and at T4 (mean 2.0 years). Lateral cephalograms were traced by hand, digitized, superimposed, and evaluated. Skeletal correction (T3 À T1) was mainly achieved through the distraction of the anterior alveolar segment in a rotational manner where the incisors were more proclined. The horizontal backward relapse (T4 À T3) measured À0.8 mm or 19.0% at point B (p < 0.001) and À1.6 mm or 25.0% at incision inferior (p < 0.001). Age, gender, amount and type (rotational versus translational) of advancement were not correlated with the amount of relapse. High angle patients (NL/ML 0 ; p < 0.01) and patients with large gonial angle (p < 0.05) showed significantly smaller relapse rates at point B. Overcorrection of the overjet achieved by the distraction was seen in a third of the patients and could be a reason for relapse. Considering the amount of skeletal relapse the DOG could be an alternative to bilateral sagittal split osteotomy for mandibular advancement in selected cases.

Clinical Paper Orthognathic SurgerySkeletal and dental stability of segmental distraction of the anterior mandibular alveolar process. A 2-year follow-up Abstract. 33 patients (27 females; 6 males) were retrospectively analysed for skeletal and dental relapse before distraction osteogenesis (DOG) of the mandibular anterior alveolar process at T1 (17.0 days), after DOG at T2 (mean 6.5 days), at T3 (mean 24.4 days), and at T4 (mean 2.0 years). Lateral cephalograms were traced by hand, digitized, superimposed, and evaluated. Skeletal correction (T3 À T1) was mainly achieved through the distraction of the anterior alveolar segment in a rotational manner where the incisors were more proclined. The horizontal backward relapse (T4 À T3) measured À0.8 mm or 19.0% at point B (p < 0.001) and À1.6 mm or 25.0% at incision inferior (p < 0.001). Age, gender, amount and type (rotational versus translational) of advancement were not correlated with the amount of relapse. High angle patients (NL/ML 0 ; p < 0.01) and patients with large gonial angle (p < 0.05) showed significantly smaller relapse rates at point B. Overcorrection of the overjet achieved by the distraction was seen in a third of the patients and could be a reason for relapse. Considering the amount of skeletal relapse the DOG could be an alternative to bilateral sagittal split osteotomy for mandibular advancement in selected cases.

This study evaluated soft tissue changes in adult patients treated with distraction osteogenesis (DOG) of the anterior mandibular alveolar process and related it to different parameters. 33 patients (27 females; 6 males) were analysed retrospectively before surgery at T1 (17.0 days), after surgery at T2 (mean 6.5 days), at T3 (mean 24.4 days), and at T4 (mean 2.0 years). Lateral cephalograms were traced by hand, digitized, superimposed, and evaluated. Statistical analysis was carried out using Kolmogorov-Smirnov test, paired t test, Pearson's correlation coefficient, and linear backward regression analysis. 2 years postoperatively (T4), the net effect of the soft tissue at point B' was 100% of the advancement at point B whilst the lower lip (labrale inferior) followed the advancement of incision inferior to 46%. Increased preoperative age was correlated (p<0.05) with more horizontal backward movement (T4-T3) for labrale superior and pogonion'. Higher NL/ML' angles were significantly correlated (p<0.05) with smaller horizontal soft tissue change at point B'. Gender and the amount of skeletal and dental advancement were not correlated with postoperative soft tissue changes (T4-T3). DOG of the anterior mandibular alveolar process is a valuable alternative for mandibular advancement regarding soft tissue change and predictability.

Soft tissue changes were analysed retrospectively in 17 patients following distraction osteogenesis (DO) of the mandibular anterior alveolar process. Lateral cephalograms were traced by hand, digitized, superimposed, and evaluated at T1 (17.0 days), after DO at T2 (mean 6.5 days), at T3 (mean 24.4 days), at T4 (mean 2.0 years), and at T5 (mean 5.5 years). Statistical analysis was carried out using Kolmogorov-Smirnov test, paired t-test, Pearson's correlation coefficient, and linear backward regression analysis. 5.5 years postoperatively, the net effect for the soft tissue at point B' was 88% of the advancement at point B while the lower lip (labrale inferior) followed the advancement of incision inferior to 24%. Increased preoperative age was correlated (p<0.05) with more horizontal backward movement (T5-T3) for labrale inferior and pogonion'. Higher NL/ML' angles were significantly correlated (p<0.05) to smaller horizontal soft tissue change at labrale inferior (T5-T3). The amount of advancement at point B was significantly correlated with an upward movement (T5-T3) of labrale inferior (p<0.01) and stomion inferior (p<0.05). It can be concluded that further change in soft tissues occurred between 2.0 and 5.5 years postoperatively. The physiological process of ageing and loss of soft tissue elasticity should be considered as possible reasons

Clinical Study Orthognathic SurgeryNeurosensory and functional evaluation in distraction osteogenesis of the anterior mandibular alveolar process Abstract. Neurosensory status and craniomandibular function of 19 patients (mean age 35.2 years, range 17.8-58.8 years) treated by combined surgical orthodontic treatment with distraction osteogenesis of the mandibular anterior alveolar process (DO group) was compared with that in 41 orthodontically treated patients (mean age 22.9 years, range 15.1-49.0 years; control group). Clinical examination took place on average 5.9 years (DO group) and 5.4 years (control group) after treatment ended. Neurosensory status was determined by two-point discrimination (2-pd) and the pointed and blunt test. Lateral cephalograms evaluated advancement of the mandibular alveolar process and possible relapse. There was no significant difference in craniomandibular function and neurosensory status between the groups. Age was significantly correlated with 2-pd at the lips (DO: p = 0.01, R = 0.575; control group: p = 0.039, R = 0.324) and chin (DO: p = 0.029, R = 0.501; control group: p = 0.008, R = 0.410). Younger patients had smaller 2-pd values. Gender, age, the amount of advancement, and relapse at point B or incision inferior show no correlation with craniomandibular function and neurosensory impairment. DO of the mandibular anterior alveolar process is a valuable and safe method with minor side effects regarding neurosensory impairment.

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