Association between dental agenesis and facial morphology. A cross-sectional study in France.

Purpose: Knowing the features of dental evolution and facial morphology, marked by an increase in the prevalence of agenesis and a tendency towards verticalization of the face, the main objective of this cross-sectional observational study was to assess the correlation between the occurrence of agenesis (of 3rd molars or other teeth) and facial morphology in the French population.

Methods: The study was conducted at the University Hospital of Rennes, France, from June 2022 to October 2022. Patients aged 12-18 years who underwent a global orthodontic assessment were included.

Are protective measures against Covid-19 still active in orthodontic practices? A cross-sectional online survey of French orthodontists three years on from the pandemic.

Purpose: The Covid-19 epidemic has imposed profound changes on the practice of orthodontics. It was in this anxiety-inducing context that drastic measures were imposed on orthodontists. The main aim of this online survey is to highlight the measures that are still in place in French orthodontic practices three years after the emergence of the pandemic.

Pain during primary molar local anaesthesia with SleeperOne5 computerized device versus conventional syringe: A randomized, split-mouth, crossover, controlled trial.

Background: Because of controversial results from clinical studies comparing different dental local anesthesia methods in children, the primary objective of this randomized, split-mouth, crossover, controlled trial was to compare pain intensity during local anaesthesia (LA) performed with a computer-controlled LA delivery system (C-CLADS) versus a conventional syringe (CONV). Secondary objectives included comparisons during dental treatment.

Methods: Participants (4-8 years) with tooth pair requiring similar treatment were recruited from five French hospitals.

Bioglass 45S5, a relevant alternative to autogenous harvesting for secondary alveolar bone grafts in clefts? Retrospective study of one hundred surgeries.

The secondary alveolar bone grafting (SABG) step restores the continuity of the alveolar bone necessary for dentition. Faced with the complications of autografts, synthetic biomaterials such as Bioglass (BG) 45S5 have been proposed. The objective was to evaluate the success rate of SABG with the addition of BG 45S5 and to highlight the prognostic factors.

OSCEGame: A serious game for OSCE training.

Background: Objective Structured Clinical Examinations (OSCEs) are amongst the most anxiety-provoking competency assessment methods. An online serious game (OSCEGame) was developed and implemented within the OSCE curriculum. This study aimed to evaluate the usefulness of this serious game on preparedness and reducing OSCE-related stress.

Oral manifestations of Alagille syndrome.

Alagille syndrome (AGS) is a multisystem disorder classically involving liver and heart failure, characteristic vertebral and facial features and ocular abnormalities. AGS is caused by heterozygous mutations in JAG1 or NOTCH2, with variable phenotype penetrance. We report two cases of AGS in children with tooth defects characterised by green discolouration and hypomineralisation.

A targeted next-generation sequencing assay for the molecular diagnosis of genetic disorders with orodental involvement.

Background: Orodental diseases include several clinically and genetically heterogeneous disorders that can present in isolation or as part of a genetic syndrome. Due to the vast number of genes implicated in these disorders, establishing a molecular diagnosis can be challenging. We aimed to develop a targeted next-generation sequencing (NGS) assay to diagnose mutations and potentially identify novel genes mutated in this group of disorders.

Amelotin: an enamel matrix protein that experienced distinct evolutionary histories in amphibians, sauropsids and mammals.

Background: Amelotin (AMTN) is an ameloblast-secreted protein that belongs to the secretory calcium-binding phosphoprotein (SCPP) family, which originated in early vertebrates. In rodents, AMTN is expressed during the maturation stage of amelogenesis only. This expression pattern strongly differs from the spatiotemporal expression of other ameloblast-secreted SCPPs, such as the enamel matrix proteins (EMPs).

Dental complications of rickets in early childhood: case report on 2 young girls.

Vitamin D is an essential hormone for calcium gut absorption. It is also involved in child growth, cancer prevention, immune system responses, and tooth formation. Due to inadequate vitamin D intake and/or decreased sunlight exposure, vitamin D deficiency has resurfaced in developed countries despite known inexpensive and effective preventive methods.

Conservation of amelogenin gene expression during tetrapod evolution.

Well studied in mammals, amelogenesis is less known at the molecular level in reptiles and amphibians. In the course of extensive studies of enamel matrix protein (EMP) evolution in tetrapods, we look for correlation between changes in protein sequences and temporospatial protein gene expression during amelogenesis, using an evo-devo approach. Our target is the major EMP, amelogenin (AMEL) that plays a crucial role in enamel structure.

Loss of teeth and enamel in tetrapods: fossil record, genetic data and morphological adaptations.

Since their recruitment in the oral cavity, approximately 450 million years ago, teeth have been subjected to strong selective constraints due to the crucial role that they play in species survival. It is therefore quite surprising that the ability to develop functional teeth has subsequently been lost several times, independently, in various lineages. In this review, we concentrate our attention on tetrapods, the only vertebrate lineage in which several clades lack functional teeth from birth to adulthood.

The origin and evolution of enamel mineralization genes.

Background/aims: Enamel and enameloid were identified in early jawless vertebrates, about 500 million years ago (MYA). This suggests that enamel matrix proteins (EMPs) have at least the same age. We review the current data on the origin, evolution and relationships of enamel mineralization genes.

Amphibian teeth: current knowledge, unanswered questions, and some directions for future research.

Elucidation of the mechanisms controlling early development and organogenesis is currently progressing in several model species and a new field of research, evolutionary developmental biology, which integrates developmental and comparative approaches, has emerged. Although the expression pattern of many genes during tooth development in mammals is known, data on other lineages are virtually non-existent. Comparison of tooth development, and particularly of gene expression (and function) during tooth morphogenesis and differentiation, in representative species of various vertebrate lineages is a prerequisite to understand what makes one tooth different from another.

Morphological variations in a tooth family through ontogeny in Pleurodeles waltl (Lissamphibia, Caudata).

Most nonmammalian species replace their teeth continuously (so-called polyphyodonty), which allows morphological and structural modifications to occur during ontogeny. We have chosen Pleurodeles waltl, a salamander easy to rear in the laboratory, as a model species to establish the morphological foundations necessary for future molecular approaches aiming to understand not only molecular processes involved in tooth development and replacement, but also their changes, notably during metamorphosis, that might usefully inform studies of modifications of tooth morphology during evolution. In order to determine when (in which developmental stage) and how (progressively or suddenly) tooth modifications take place during ontogeny, we concentrated our observations on a single tooth family, located at position I, closest to the symphysis on the left lower jaw.

Tooth development in a scincid lizard, Chalcides viridanus (Squamata), with particular attention to enamel formation.

Comparative analysis of tooth development in the main vertebrate lineages is needed to determine the various evolutionary routes leading to current dentition in living vertebrates. We have used light, scanning and transmission electron microscopy to study tooth morphology and the main stages of tooth development in the scincid lizard, Chalcides viridanus, viz., from late embryos to 6-year-old specimens of a laboratory-bred colony, and from early initiation stages to complete differentiation and attachment, including resorption and enamel formation.

Dentition and tooth replacement pattern in Chalcides (Squamata; Scincidae).

This study was undertaken as a prerequisite to investigations on tooth differentiation in a squamate, the Canarian scincid Chalcides. Our main goal was to determine whether the pattern of tooth replacement, known to be regular in lizards, could be helpful to predict accurately any stage of tooth development. A growth series of 20 laboratory-reared specimens, aged from 0.

First-generation teeth in nonmammalian lineages: evidence for a conserved ancestral character?

The present study focuses on the main characteristics of first-generation teeth (i.e., the first teeth of the dentition to develop in a given position and to become functional) in representatives of the major lineages of nonmammalian vertebrates (chondrichthyans, actinopterygians, and sarcopterygians: dipnoans, urodeles, squamates, and crocodiles).