Ectodermal dysplasias (ED) are a clinically and genetically heterogeneous group of hereditary disorders that have in common abnormal development of ectodermal derivatives. Hypohidrotic ectodermal dysplasia (HED) is characterized by abnormal development of eccrine sweat glands, hair, and teeth. The X-linked form of the disease, caused by mutations in the EDA gene, represents the majority of patients with the hypohidrotic form. Autosomal dominant and autosomal recessive forms are occasionally seen, and result from mutations in at least three genes (WNT10A, EDAR, or more rarely EDARADD). We have screened for mutations in EDAR (commonly involved in the hypohidrotic form) and WNT10A (involved in a wide spectrum of ED and in isolated hypodontia) in a cohort of 36 patients referred for EDA molecular screening, which failed to identify any mutation. We identified eight EDAR mutations in five patients (two with homozygous mutations, one with compound heterozygous mutations, and two with heterozygous mutation), four of which were novel variants. We identified 28 WNT10A mutations in 16 patients (5 with homozygous mutations, 7 with compound heterozygous mutations, and 4 with heterozygous mutations), seven of which were novel variants. Our study allows a more precise definition of the phenotypic spectrum associated with EDAR and WNT10A mutations and underlines the importance of the implication of WNT10A among patients with ED.

Introduction: Dental education emphasises the acquisition of technical skills. Recent advances in 3D printing technologies have enabled the emergence of new educational tools usable in hands-on work sessions. The possibility to print 3D models from CT scans of patients is now available to dental practitioners. The aim of this study was to develop and evaluate a 3D printed model for paediatric dentistry training and compare it to the reference model used in our faculty.Materials and Method: 3D models were obtained by modifying and printing the CT scan of a young patient using the Voco® Solflex 350 3D® printer and Voco® V-print resin. Thirty-four students were asked to perform a pulpotomy and preparation for a stainless steel paediatric crown on tooth 85 on both the 3D printed model and the industrial model (Frasaco®), and then to answer a questionnaire. The data were analysed using R software.Result: Both models obtained high scores. The learning potential and its applicability to clinical practice showed no statistically significant difference. Although the colour and the simulation of the proximal area disturbed the students (P = 0.009), the 3D models were seen as a good idea (P = 0.012). When it came to model design, the students appreciated the simulation of caries on 3D models (P = 0.0001) and considered the use 3D of models as a more realistic experience (P = 0.017). Discussion:Although this study has some limitations (number of participants, choice of the models to be compared), it constitutes the first attempt to compare students' perception of 3D and series models. It shows that 3D technology makes it possible to obtain models of similar quality while offering a more realistic experience. Conclusion:There are still many ways in which these models could be improved. For example, modifying the quality of resins could improve the milling sensation, and the design could be improved to achieve better contact points. Nevertheless, these 3D models offer the possibility to give the patient a more central place in the education of future practitioners. K E Y W O R D S 3D printing, hands-on models | 69 MARTY eT Al. How to cite this article: Marty M, Broutin A, Vergnes J-N, Vaysse F. Comparison of student's perceptions between 3D printed models versus series models in paediatric dentistry hands-on session. Eur J Dent Educ. 2019;23:68-72. https://doi.

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Acute leukaemia is the most common type of childhood cancer, the acute lymphoblastic type accounting for the majority of cases. Children affected by leukaemia receive various forms of treatments including chemotherapeutic agents and stem cell transplants. Leukaemia and its treatment can directly or indirectly affect oral health and further dental treatments. The oral complications include mucositis, opportunistic infections, gingival inflammation and bleeding, xerostomia and carious lesions. An additional consideration in children is the impact of the treatments on the developing dentition and on orofacial growth. The aim of this review is to describe the oral complications in children with acute lymphoblastic leukaemia and the methods of prevention and management before, during and after the cancer treatment.

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Hypophosphatasia is an inheritable disorder characterised by defective bone mineralisation due to the impaired activity of tissue-non-specific alkaline phosphatase (AP). Clinical presentation ranges from stillbirth without mineralised bone to pathological fractures in late adulthood. During childhood, the main manifestations include rickets, growth delay and dental problems. Fractures and bone pain usually characterise the adult form. A 9-year-old girl was referred for repetitive fractures after minimal trauma. She had normal growth, normal sclerae, no rickets and minimal dental abnormalities. Her sister had also presented fractures. The proband, her sister and mother had low total and bone-specific AP levels and E435K mutation in exon 12 of the liver/bone/kidney AP gene. Low AP levels must lead to genetic analysis. Bone fragility and repetitive fractures may be symptoms of hypophosphatasia in childhood, which must not be neglected. Associated factors such as vitamin D or calcium deficiency must be prevented. In conclusion, hypophosphatasia must not be forgotten as an aetiological factor of repetitive fractures or bone pain in children and AP activity should be checked accurately.

For some traits, the human genome is more closely related to either the bonobo or the chimpanzee genome than they are to each other. Therefore, it becomes crucial to understand whether and how morphostructural differences between humans, chimpanzees and bonobos reflect the well known phylogeny. Here we comparatively investigated intra and extra labyrinthine semicircular canals orientation using 260 computed tomography scans of extant humans (Homo sapiens), bonobos (Pan paniscus) and chimpanzees (Pan troglodytes). Humans and bonobos proved more similarities between themselves than with chimpanzees. This finding did not fit with the well established chimpanzee – bonobo monophyly. One hypothesis was convergent evolution in which bonobos and humans produce independently similar phenotypes possibly in response to similar selective pressures that may be associated with postural adaptations. Another possibility was convergence following a “random walk” (Brownian motion) evolutionary model. A more parsimonious explanation was that the bonobo-human labyrinthine shared morphology more closely retained the ancestral condition with chimpanzees being subsequently derived. Finally, these results might be a consequence of genetic diversity and incomplete lineage sorting. The remarkable symmetry of the Semicircular Canals was the second major finding of this article with possible applications in taphonomy. It has the potential to investigate altered fossils, inferring the probability of post-mortem deformation which can lead to difficulties in understanding taxonomic variation, phylogenetic relationships, and functional morphology.