[Dentoalveolar adaptation in vertical jaw-base discrepancies]

The aim of this study was to determine the constancy and the extent of the dentoalveolar adaptation in subjects with disharmonious vertical jaw base relationships. Lateral head films in centric occlusion of 66 untreated adults were analysed. The subjects were divided in three facial type groups on the basis of the mandibular base angle (ML/NSL): hypodivergent (n = 23), normodivergent (n = 18), and hyperdivergent (n = 25). The relationships between maxillary and mandibular anterior and posterior dentoalveolar heights and vertical jaw base relationship were ascertained. The study revealed the following: an increase in vertical jaw base angle resulted in 1. an increase in maxillary and mandibular anterior and posterior dentoalveolar heights, 2. a larger increase in maxillary than in mandibular dentoalveolar height, and, 3. a larger increase in anterior than posterior dentoalveolar height. The study divulged the presence of dentoalveolar adaptation in subjects with a divergent vertical jaw base relationship. This adaptation, however, was inconsistent and in some cases incomplete.