Developmental disturbances associated with agenesis of the permanent maxillary lateral incisor

The aim of this study was to characterise the intra and extra-oral phenotype associated with agenesis of the permanent maxillary lateral incisor. We compared three groups: (1) subjects with agenesis of one or both permanent maxillary lateral incisors (n=80); (2) first and second degree relatives of group 1 with no agenesis of the permanent maxillary lateral incisor and (3) subjects with no agenesis of the maxillary lateral incisor or family history of it (n=49). For each of the 201 subjects detailed clinical information was reviewed and panoramic radiographs were analysed. Considering only the sample with unilateral agenesis, microdontia of the contralateral permanent maxillary lateral incisor was significantly more frequent in group 1 (82.4%) than in group 2 (25%) and the control group (2%). This supports the theory that microdontia is a variable expression of the same developmental disturbance that causes tooth agenesis. The absence of third molars occurred more often in group 1 (36.2%) than in groups 2 and 3 (18.6% and 18.9% respectively), confirming that agenesis of third molars was markedly associated with the agenesis of the permanent maxillary lateral incisor. Agenesis of teeth other than third molars was not significantly different among subjects with agenesis of the permanent maxillary lateral incisor and their relatives. The frequencies of supernumerary teeth, permanent maxillary canine impaction, general health condition and minor anomalies were not significantly different between the three groups

Dentofacial characteristics of patients with hypodontia

Item does not contain fulltextThis study aims to identify distinctive dentofacial characteristics of hypodontia patients. For this purpose, 189 young hypodontia patients (cases) were divided into subgroups, based on criteria from literature. Normalised differences between cases and controls were calculated for various parameters of dentofacial form. Subsequently, cluster analysis was applied to disclose subsets of hypodontia patients with distinctive dentofacial features. The ANB angle, interincisal angle and lower anterior face height were consistently significantly different amongst the subsets. Four clusters of patients with an increasing number of missing teeth and distinctive dentofacial characteristics could be identified. Patients in cluster 1 display a high-angle facial pattern. Patients in clusters 2 and 3 exhibit markable dentoalveolar characteristics (a relatively small and a large interincisal angle, respectively). Patients in cluster 4 exhibited notable sagittal-skeletal discriminative features predominantly because of a retrognathic maxilla. The smallest nasolabial angle and lower anterior face height were seen in this cluster. It is concluded that the anterior-posterior relationship between the jaws, the interincisal angle and the lower anterior face height are discriminative parameters of dentofacial form in hypodontia patients. Patients with hypodontia can be clustered in four groups, each with distinctive vertical-skeletal, dentoalveolar and sagittal-skeletal characteristics. This categorisation of patients with hypodontia into meaningful groups may be useful for treatment planning, interdisciplinary communication and as a means of identifying groups of patients that qualify for reimbursement of costs. Other dental factors should be appreciated as well during restorative clinical decision making in patients with hypodontia.1 augustus 201