Hyperdivergent Facial Types Research Articles

Overbite depth indicator with particular reference to anterior open-bite

0 bservation and experience emphasize the conviction that control of the vertical component of malocclusion is one of the most difficult tasks in orthodontics. The anteroposterior component as one dimension has been amply analyzed and discussed; however, information concerning the vertical component as the other dimension is insufficient. Consequently, certain types of malocclusion occasionally manifest themselves in undesirable situations during treatment and lead to unsatisfactory results. In this aspect of orthodontics, strong emphasis has been placed on the correlation between the overbite and the steepness of the mandible,l* 2 the degree of gonial angle, *, 3 the degree of occlusomandibular plane angle,4 the ratio between the anterior and posterior facial heights,5-7 and, to a lesser degree, a number of other insignificant correlations. Among these known diagnostic measurements, the degree of the mandibular plane angle is perhaps the most widely accepted and implied reference measurement. In fact, the terms hyperdivergence and hypodivergence have been introduced by Schudyl and are commonly used as significant diagnostic criteria. The hyperdivergent facial type supposedly indicates an open-bite or a tendenc$ toward an open-bite, whereas hypodivergency supposedly expresses a facial type with a deep overbite or an overbite tendency. Both types are verified and designated by the degree of the mandibular plane angle. Experience has taught that the correlation between the mandibular plane angle and the overbite is not a dependable factor upon which to base the diagnosis and the treatment plan, As a matter of fact, it is too often observed that there are deep overbite malocclusions in the hyperdivergent facial type. Similarly, open-bite malocclusions are found also in the hypodivergent facial type. It has frequently been observed that, in the course of treatment, a certain malocclusion with a moderate degree of overbite resulted in an anterior open-bite. Conversely, in a certain malocclusion that initially appeared to be an open-bite,