Evaluation of changes in the vertical facial dimension with different anchorage systems in extraction and non-extraction subjects treated by Begg fixed appliances: a retrospective study.Eur J Orthod. 2007 Oct; 29(5):508-16.EJ
The aim of the study was to evaluate and compare the effects of mesial movement of the maxillary and mandibular molars on the facial vertical dimensions following orthodontic treatment. Patients with an Angle Class I malocclusion were treated by four first premolar extractions and Begg fixed appliances (moderate and maximum anchorage groups), while those with an Angle Class II malocclusion were treated by Begg intraoral distalization mechanics without extractions (distalization group). Following treatment, the patients were grouped according to the mesial movement of the mandibular first molars and compared with an Angle Class I control group. All groups comprised 15 patients, their mean pre-treatment ages were 14.95 years for the moderate (13 females, 2 males), 14.88 years for the maximum (13 females, 2 males), 14.41 years for the distalization (10 females, 5 males), and 14.38 years for the control (13 females, 2 males) groups. Lateral cephalometric measurements were performed at two time points (T(1): pre-treatment/control, T(2): post-treatment/control). A paired t-test was used for within-group comparisons and non-parametric Kruskal-Wallis and Dunn's multiple-comparison tests to determine any differences. The increases in anterior and posterior face heights were similar between groups. The mandibular plane angle (SN/GoGn) was increased in all treatment groups, while it decreased in the control group. Although SN/GoGn increased more in the distalization and less in the moderate anchorage groups, these differences were not statistically significant. The change in SN/GoGn was significantly different only between the distalization and control groups. Facial vertical dimensions were not significantly affected by the amount of mesial movement of the molar teeth.