ORIGINAL ARTICLE Cephalometric assessment of dentofacial vertical changes in Class I subjects treated with and without extraction Arunachalam Sivakumar a and Ashima Valiathan b Manipal, India, and Cleveland, Ohio Introduction: There is disagreement concerning the effect of premolar extractions on the dentofacial vertical dimension. It has been suggested that orthodontic forward movement of the posterior teeth after first premolar extraction leads to reduction in vertical dimension. The purpose of this study was to examine cephalometrically the dentofacial vertical changes in Class I Indian subjects treated with and without extractions. Methods: The extraction group included 31 normodivergent patients (26 female, 5 male; pretreatment age, 17.19  3.89 years) with maxillary and mandibular first premolar extractions. The nonextraction group included 29 patients (18 female, 11 male; pretreatment age, 18.48  3.61 years). A coordinate system with the Frankfort horizontal plane and a mandibular fiduciary line was used for the cephalometric calibration. To determine vertical dimension changes due to treatment and to compare differences between the 2 groups, paired and unpaired t tests were performed, respectively. Results: Both groups had increases in linear vertical dimensions (P 0.05), but the change was comparatively greater in the extraction group (P 0.05). Mesial movement of the maxillary and mandibular posterior teeth was coincidental with the extrusion to such an extent that it increased the vertical dimension, although the mandibular plane angle remained unchanged during treatment. Conclusions: Extraction of teeth only to increase the overbite or decrease the mandibular plane angle might not be justified. (Am J Orthod Dentofacial Orthop 2008;133:869-75) I n this era of mushrooming research and technolog- ical advances, we still have many unanswered or debatable questions. Much research has been fo- cused on an intriguing question: does the vertical dimension of the face decrease with therapeutic premo- lar extraction? Although this conundrum has been around since the beginning of orthodontics, it has surfaced in debates among many clinicians recently. Thus, it is current conventional wisdom that it is desirable to extract teeth in patients with vertical facial patterns to help control the vertical dimension. It is further believed that extraction should be avoided in brachyfacial types to prevent excessive vertical clo- sure. 1,2 The dentoalveolar apparatus is assumed to take the form of an occlusal wedge so that the bite is opened when molars or premolars are extruded or distalized, or it is closed when the molars are moved forward after extraction of the premolars. 3,4 From a biomechanical point of view, this belief is logical and self-explanatory. Unlike other dental treatments, orthodontic mechano- therapy is performed in an environment of biological complexities and complexities associated with the treat- ment per se. Hence, any differences of opinion regard- ing this rule (occlusal wedge hypothesis) are not surprising. Recent studies evaluating the effect of first premo- lar extractions on the vertical dimension concluded that vertical changes after the extraction of first premolars were not statistically different from those in nonextrac- tion patients, and that the attempt to help control (close) the vertical dimension with the extraction of first premolars was not possible. 5,6 A few studies demon- strated increases in the absolute values of anterior and posterior facial heights, even with premolar extraction with no further change in the mandibular plane angle (MPA). 7-10 Some studies suggest that it takes special effort, in addition to the premolar extractions, to reduce the vertical dimension in patients with high MPAs. Pearson 11 showed a mean decrease in MPA of 3.9° after premolar extractions, with vertical chincups used before and during orthodontic treatment. Garlington 12 attempted to reduce the vertical dimension through From the Department of Orthodontics and Dentofacial Orthopedics, Manipal College of Dental Sciences, Manipal, India. a Reader. b Professor and head, adjunct professor of Orthodontics, Case Western Reserve University, Cleveland, Ohio. Reprint requests to: Arunachalam Sivakumar, Department of Orthodontics and Dentofacial Orthopedics, Manipal College of Dental Sciences, Manipal 576104, India; e-mail, sivlalith2004@yahoo.co.in. Submitted, March 2006; revised and accepted, May 2006. 0889-5406/$34.00 Copyright © 2008 by the American Association of Orthodontists. doi:10.1016/j.ajodo.2006.05.041 869