Dentoalveolar rotation in correction of Class II malocclusion

Abstract

A recent orthodontic investigation reports that Class II dentofacial problems may be termed a syndrome and, further, reported an estimated 128 possible subdivisions within the Class II umbrella.’ Most clinicians are aware of this intragroup variability, as evidenced by the array of differential analyses, multiplicity of treatment plans, and everexpanding mechanotherapy that these situations require. These combined complexities serve to emphasize the challenge faced in achieving a successful conclusion in the Class I1 case. Similarly, in attempting to understand clearly the treatment results of these diverse Class II cases, a more discriminating and specific effort may be necessary. The cephalometric analyses employed to illustrate the Class II correction include conventional linear and angular comparisons of reference planes and structural elements of the skeletal, dental, and facial components. One of the most useful guides in estimating treatment results is the alteration and/or stability of the occlusal plane because, obviously, our appliances directly affect the denture area. Indirectly, changes in the denture components affect facial esthetics, skeletal pattern, occlusal functions, and retentive stabilityS2 It has been suggested in the literature 3-5 that occlusal plane changes and/or stability often mask important changes which have taken place within the segments of the dentoalveolar portion of the denture because the occlusal plane includes the entire maxillary and mandibular elements of the anterior and posterior teeth in a geometric fashion which reduces inherent differences to a common denominator. In particular, Schudy6 commenting upon the behavior of the occlusal plane in treatment, pinpoints the problem: “The occlusal plane is not an anatomical part, but a boundary between two parts . . maxillary and mandibular teeth. . . . If we will always relate posterior and anterior segments of teeth to their respective bases, we will not become confused about occlusal plane changes.” A more detailed investigation of the denture area may yield potentially useful information. Therefore, for the purpose of this article, the occlusal plane will be segregated into six components-anterior, middle, and posterior parts of the maxillary and mandibular arches, including their alveolar elements. The dentoalveolar elements will be incorporated to provide a two-dimensional structure for description, measurement, and comparison. The specific purpose of this article is to describe the dentoalveolar components and their changes during treatment from six successfully treated Class II cases exhibiting a major crania-facie-dental variant, such as a Class II, Division 1 malocclusion in a nongrowing adult. Finally, these variants will be related to the behavior of the conventional occlusal planes and discussed in relation to clinical implications.