Mutations in the latent TGF-beta binding protein 3 (LTBP3) gene cause brachyolmia with amelogenesis imperfecta.

Inherited dental malformations constitute a clinically and genetically heterogeneous group of disorders. Here, we report on four families, three of them consanguineous, with an identical phenotype, characterized by significant short stature with brachyolmia and hypoplastic amelogenesis imperfecta (AI) with almost absent enamel. This phenotype was first described in 1996 by Verloes et al. as an autosomal recessive form of brachyolmia associated with AI. Whole-exome sequencing resulted in the identification of recessive hypomorphic mutations including deletion, nonsense and splice mutations, in the LTBP3 gene, which is involved in the TGF-beta signaling pathway. We further investigated gene expression during mouse development and tooth formation. Differentiated ameloblasts synthesizing enamel matrix proteins and odontoblasts expressed the gene. Study of an available knockout mouse model showed that the mutant mice displayed very thin to absent enamel in both incisors and molars, hereby recapitulating the AI phenotype in the human disorder.

The systemic diagnosis / Le diagnostic systémique

INTRODUCTION: Orthodontic diagnosis is generally centered on the morphological aspect, as is the treatment: it is most often a matter of modifying the shape of the arches and their relationships to adjust them to a morphological norm with the goal of a beautiful smile. However legitimate it may be, this diagnostic approach may seem reductive if we consider that teeth are also used to chew: it is even their main function. But how to take into account the masticatory function? MATERIALS AND METHODS: With the help of clinical examples, the author develops the modalities of the clinical exploration of the mandibular kinematics, reflection of the mastication, on which the systemic diagnosis is based. It highlights the proprioceptive resources of the masticatory system that systemic treatment targets during the correction of malocclusions. CONCLUSION: The systemic diagnosis highlights the functional role of the arches, inviting, during their correction, to rehabilitate mastication in order to improve their stability.

INTRODUCTION: Le diagnostic orthodontique est, de façon générale, centré sur l'aspect morphologique, comme l'est d'ailleurs le traitement : il s'agit le plus souvent de modifier la forme des arcades et leurs rapports pour les ajuster à une norme morphologique avec comme finalité un beau sourire. Toute légitime qu'elle soit, cette démarche diagnostique peut paraître réductrice si l'on considère que les dents servent aussi à mastiquer : c'est même leur fonction principale. Mais comment tenir compte de la fonction masticatrice ? MATÉRIELS ET MÉTHODES: À l'aide d'exemples cliniques, l'auteur développe les modalités de l'exploration clinique de la cinématique mandibulaire, reflet de la mastication, sur laquelle se fonde le diagnostic systémique. Elle met en valeur les ressources proprioceptives du système masticateur que le traitement systémique cible lors de la correction des malocclusions. CONCLUSION: Le diagnostic systémique met en avant le rôle fonctionnel des arcades, invitant, lors de leur correction, à réhabiliter la mastication dans le but d'améliorer leur stabilité.

Treatment of Class III malocclusion: the key role of the occlusal plane.

Patients with a Class III malocclusion generally present with a counterclockwise inclination of the occlusal plane, converging with Camper's line towards the front. This slope has an effect on mandibular movement (forward posture) and on chewing mechanisms in general. As dysfunctional mastication is likely to influence facial growth and inter-arch stability negatively, early orthopedic therapy of the occlusal unbalance concurrent with Class III malocclusion is justified. The aim of this article is to present a method of Class III treatment based on a correct re-orientation of the occlusal plane in order to achieve an optimal masticatory mechanism, essential for stability of early treatment outcomes.

[The psychological impact of orthognathic surgery]. / L'impact psychologique des traitements chirurgico-orthodontiques.

We carried out an investigation on 92 patients having benefited from an orthognathic surgery, in order to demonstrate the effects of the dento-facial deformations on the patients' everyday life and the psychological impact of the multidisciplinary treatment. Questionnaires were drawn up and sent to the residence of the patients: one preoperative, transmitted 15 days before the intervention and one postoperative, addressed 6 months afterwards. Our results revealed that all the patients of our study were satisfied and that this treatment eliminated the complex of 90% of the patients. We could highlight that the more surprising part of the treatment for the patients is the postoperative facial deformation generated by the important postoperative oedema. We concluded that the information of the patient and the communication patient-expert have a preponderant role in the therapeutic caring. .