Cephalometric comparison of maxillary second molar extraction and nonextraction treatments in patients with Class II malocclusions.Am J Orthod Dentofacial Orthop. 2001 Dec; 120(6):608-13; quiz 677.AJ
This retrospective cephalometric study compared the nature of the skeletodental correction of maxillary second-molar extraction and nonextraction treatments in correcting Class II malocclusions. The sample comprised 50 Class II, deep-bite, low-angle adolescents; half were treated with maxillary second-molar extraction and half were treated without extraction. Pretreatment and posttreatment lateral cephalograms were analyzed. Analysis relied primarily on the method of Lysle Johnston that evaluates sagittal changes in the teeth and supporting bones relative to the functional occlusal plane. All 18 cephalometric variables examined were statistically equivalent between the 2 groups at the start of treatment. In contrast, several skeletodental treatment changes differed significantly. The maxillary second-molar extraction group exhibited distal movement of the maxillary first molar (1.2 mm vs 0.0 mm), and there was greater flaring of the mandibular incisors in the nonextraction group (9.1 degrees vs 3.5 degrees). The upper incisor root was torqued lingually in both groups, but there was more anterior crown movement in the nonextraction group (2.0 mm vs 0.0 mm). Also, the extraction group finished active treatment 7 months sooner on average. Sagittal molar correction in the maxillary second-molar group was a result of distalizing in the maxillary arch, whereas anchorage was expended in the mandibular arch to correct the malocclusion in the nonextraction group. In properly selected Class II malocclusions, maxillary second-molar extraction is a viable alternative treatment choice.