Oro-dental phenotyping and report of three families with RELT-associated amelogenesis imperfecta.

Amelogenesis imperfecta (AI) is a group of rare genetic conditions characterized by quantitative and/or qualitative tooth enamel alterations. AI can manifest as an isolated trait or as part of a syndrome. Recently, five biallelic disease-causing variants in the RELT gene were identified in 7 families with autosomal recessive amelogenesis imperfecta (ARAI). RELT encodes an orphan receptor in the tumor necrosis factor (TNFR) superfamily expressed during tooth development, with unknown function. Here, we report one Brazilian and two French families with ARAI and a distinctive hypomineralized phenotype with hypoplastic enamel, post-eruptive enamel loss, and occlusal attrition. Using Next Generation Sequencing (NGS), four novel RELT variants were identified (c.120+1G>A, p.(?); c.120+1G>T, p.(?); c.193T>C, p.(Cys65Arg) and c.1260_1263dup, p.(Arg422Glyfs*5)). Our findings extend the knowledge of ARAI dental phenotypes and expand the disease-causing variants spectrum of the RELT gene.

Reduced bone dimension in patients affected by oligodontia: A retrospective study on maxillary and mandibular CBCT.

AIM: Oligodontia (OD) is a rare developmental condition characterized by the absence of six or more teeth. Dental implant placement may be challenging due to anatomical factors. This study aims to evaluate the alveolar bone dimensions in OD patients compared with controls. MATERIALS AND METHODS: On maxillary and mandibular cone-beam computed tomography (CBCT), bone height and width were measured at every tooth and edentulous site. The distance to the inferior alveolar nerve was also measured. Fifty-three OD patients (40 maxillary and 32 mandibular CBCT) and 82 controls (51 maxillary and 31 mandibular CBCT) were compared using mixed models. RESULTS: Compared with those in OD patients, maxillary permanent teeth and edentulous sites showed significantly higher mean height in control patients (incisive-canine site height: +2.12 mm; edentulous incisive-canine site height: +4.46 mm [p > .001]). For the mandibular permanent teeth, mean height was higher in controls than in OD patients at the incisive-canine (+3.82 mm [p > .001]) and premolar areas (+2.06 mm [p > .001]). Only edentulous incisive-canine sites were significantly different between controls and OD patients (mean: +0.52 mm [p > .001]). Changes in alveolar nerve position were observed in case of molar agenesis. CONCLUSION: Maxillary and mandibular bone dimensions are reduced in OD patients compared with controls both in sites with permanent teeth and in edentulous areas.

Chronic oropharyngeal pain and medical nomadism in an Eagle's syndrome patient: a case report.

BACKGROUND: Elongation of the styloid process associated with oropharyngeal pain and dysphagia is known as Eagle's syndrome, a condition whose pathophysiology is still a matter of debate. Given its low prevalence and complex symptomatology, this syndrome is often misdiagnosed, leading to chronic pain and medical nomadism. A 51-year-old woman of African origin with 3-year history of left-side oropharyngeal pain and worsening dysphagia consulted several health professionals. Medical and surgical treatments, including a sinus surgery and the extraction of three healthy teeth, did not improve her symptoms. Evaluation in an orofacial pain clinic revealed an asymmetrically elongated styloid process. Surgical shortening of the elongated styloid process provided complete pain relief and recovery of normal swallowing function. CONCLUSION: Based on this case report, the pathophysiology of Eagle's syndrome is discussed, and the need for specific follow-up in a subpopulation of patients with asymptomatic styloid process elongation is highlighted.

Forensic odontology identification response to terrorist attacks in Paris November 2015.

The terrorist attacks of November 2015 led to the immediate death of 129 victims admitted to the Legal and Forensic Medicine Institute of Paris, including 41 unidentified. During the Disaster Victim Identification (DVI) operations, 22 bodies were examined by the postmortem (PM) dental team with the aim of establishing PM odontograms. At the same time, the dental expert in the antemortem (AM) unit collected a large number of dental files, progressively filtered as the list of missing persons became reduced. Feedback from these events has highlighted the difficulties of implementing the DVI chain principles in a legal framework, published the day before the attacks, and also the technical complexity of collecting dental data on a week end of terror. The return on experience after this event has represented a paradigm shift on previous methods of DVI in Paris and even more in France. Indeed, the victim identification procedure was redesigned, integrating new technical means such as a CT scan directly on spot, allowing the extraction of maxillofacial data as soon as possible in order to support the PM dental examination team. Moreover, the National Dental Council proceeded to the overall remodeling of the dental identification unit, which is composed of trained members, from local, regional and national aspects. These forensic experts are dedicated, at the request of the legal authorities, to DVI operations and deployed throughout the country capable of managing AM and PM data. This unit aims also to share experiences and awareness-raising among health professionals and investigators in order to optimize a better submission of AM elements and also to enhance the major interest of odontology as a primary identifier in disaster.

Lack of FAM20A, Ectopic Gingival Mineralization and Chondro/Osteogenic Modifications in Enamel Renal Syndrome.

Enamel renal syndrome (ERS) is a rare recessive disorder caused by loss-of-function mutations in FAM20A (family with sequence similarity 20 member A, OMIM #611062). Enamel renal syndrome is characterized by amelogenesis imperfecta, delayed or failed tooth eruption, intrapulpal calcifications, gingival overgrowth and nephrocalcinosis. Although gingival overgrowth has consistently been associated with heterotopic calcifications the pathogenesis, structure and interactions of the mineral deposits with the surrounding connective tissue are largely unknown. We here report a novel FAM20A mutation in exon 1 (c.358C > T) introducing a premature stop codon (p.Gln120*) and resulting in a complete loss of FAM20A. In addition to the typical oral findings and nephrocalcinosis, ectopic calcified nodules were also seen in the cervical and thoracic vertebrae regions. Histopathologic analysis of the gingiva showed an enlarged papillary layer associated with aberrant angiogenesis and a lamina propria displaying significant changes in its extracellular matrix composition, including disruption of the collagen I fiber network. Ectopic calcifications were found throughout the connective gingival tissue. Immunomorphological and ultrastructural analyses indicated that the calcification process was associated with epithelial degeneration and transformation of the gingival fibroblasts to chondro/osteoblastic-like cells. Mutant gingival fibroblasts cultures were prone to calcify and abnormally expressed osteoblastic markers such as RUNX2 or PERIOSTIN. Our findings expand the previously reported phenotypes and highlight some aspects of ERS pathogenesis.

Elements of morphology: Standard terminology for the teeth and classifying genetic dental disorders.

Dental anomalies occur frequently in a number of genetic disorders and act as major signs in diagnosing these disorders. We present definitions of the most common dental signs and propose a classification usable as a diagnostic tool by dentists, clinical geneticists, and other health care providers. The definitions are part of the series Elements of Morphology and have been established after careful discussions within an international group of experienced dentists and geneticists. The classification system was elaborated in the French collaborative network "TÊTECOU" and the affiliated O-Rares reference/competence centers. The classification includes isolated and syndromic disorders with oral and dental anomalies, to which causative genes and main extraoral signs and symptoms are added. A systematic literature analysis yielded 408 entities of which a causal gene has been identified in 79%. We classified dental disorders in eight groups: dental agenesis, supernumerary teeth, dental size and/or shape, enamel, dentin, dental eruption, periodontal and gingival, and tumor-like anomalies. We aim the classification to act as a shared reference for clinical and epidemiological studies. We welcome critical evaluations of the definitions and classification and will regularly update the classification for newly recognized conditions.

Translation and cross-cultural validation of the French version of the Sleep-Related Breathing Disorder scale of the Pediatric Sleep Questionnaire.

BACKGROUND: Sleep-disordered breathing (SDB), including obstructive sleep apnea syndrome, is often underestimated because it requires a burdensome test (ie, polysomnography) to ensure diagnosis. To improve polysomnography referral, it is of utmost importance to validate efficient alternative screening tools. This study aimed to provide a translation and a cross-cultural validation of the Pediatric Sleep Questionnaire (PSQ) into French to obtain an easy-to-use and reliable screening tool. The psychometric properties of the French version were also determined. METHODS: The process of cross-cultural adaptation was carried out following these steps: forward-backward translation, evaluation by an expert committee, and pretesting of the pre-final version. Reliability of the French-PSQ version was assessed by Cronbach's alpha coefficients and Spearman's correlation on a convenient sample of 201 children (aged between 2 and 17 years). Construct validity was determined by factor analysis of principal components. RESULTS: Internal consistency was within an adequate range for all subscales: 0.711 for snoring, 0.559 for sleepiness, 0.682 for behavioral problems, and 0.776 for the whole questionnaire. Spearman's correlation analysis comparing questionnaires administered two weeks apart showed good correlation coefficients for all subscales (snoring: 0.642, sleepiness: 0.846, behavioral problems: 0.780, and entire SRBD scale: 0.835). Factor analysis performed to assess the structure of the French-SRBD scale confirmed the same four factors described in the original questionnaire ("breathing," "behavior," "sleepiness," and "other"). CONCLUSION: The French version of the PSQ has been successfully cross-culturally adapted and showed good psychometric properties, suggesting that it is useful as a tool to screen sleep-disordered breathing in French-speaking children.

Gustatory modulation of the responses of trigeminal subnucleus caudalis neurons to noxious stimulation of the tongue in rats.

Certain tastants inhibit oral irritation by capsaicin, whereas anesthesia of the chorda tympani (CT) enhances oral capsaicin burn. We tested the hypothesis that tastants activate the CT to suppress responses of trigeminal subnucleus caudalis (Vc) neurons to noxious oral stimuli. In anesthetized rats, we recorded Vc unit responses to noxious electrical, chemical (pentanoic acid, 200 µm) and thermal (55 °C) stimulation of the tongue. Electrically evoked responses were significantly reduced by a tastant mix and individually applied NaCl, monosodium glutamate (MSG), and monopotassium glutamate. Sucrose, citric acid, quinine and water (control) had no effect. Pentanoic acid-evoked responses were similarly attenuated by NaCl and MSG, but not by other tastants. Responses to noxious heat were not affected by any tastant. Transection and/or anesthesia of the CT bilaterally affected neither Vc neuronal responses to electrical or pentanoic acid stimulation, nor the depressant effect of NaCl and MSG on electrically evoked responses. Calcium imaging showed that neither NaCl nor MSG directly excited any trigeminal ganglion cells or affected their responses to pentanoic acid. GABA also had no effect, arguing against peripheral effects of GABA, NaCl or MSG on lingual nocicepive nerve endings. The data also rule out a central mechanism, as the effects of NaCl and MSG were intact following CT transection. We speculate that the effect is mediated peripherally by the release from taste receptor cells (type III) of some mediator(s) other than GABA to indirectly inhibit trigeminal nociceptors. The results also indicate that the CT does not exert a tonic inhibitory effect on nociceptive Vc neurons.

Change in sinus membrane dimension following sinus floor elevation: a retrospective cohort study.

OBJECTIVES: To investigate: (1) the effect of the lateral window technique for maxillary sinus augmentation on sinus membrane thickness, and (2) to identify factors associated with the mean postoperative surgical space. MATERIAL AND METHODS: This retrospective cohort study included 37 sinuses corresponding to 37 consecutive patients referred for maxillary sinus augmentation procedures aiming to increase with deproteinized bovine bone the surgical space for dental implant placement in the posterior maxilla. A total of 74 preoperative and postoperative computed tomography were analyzed with regard to the thickness of the sinus membrane. A linear regression model was used to explain the difference between the mean preoperative and postoperative surgical space RESULTS: No significant change in the membrane thickness was shown between pre and postoperative CT scans. The mean height of the graft was 12 mm (P < 0.001), resulting in a significant augmentation of the surgical space (P < 0.001). The multivariate analysis performed to identify variables associated with the postoperative surgical space shows that current smoking significantly reduces the chance to achieve the mean value of the surgical space normally expected in this type of surgical procedure (P = 0.02). No significant effect of complications, history of periodontal disease or ENT was found. CONCLUSION: Our findings suggest that: (1) sinus floor augmentation via a lateral approach with deproteinized bovine bone alone has no impact on the natural sinus physiology; and (2) that the mean postoperative surgical space may be affected by smoking.

[Radiation Protection in Orthodontics: relevant data]. / La radioprotection en orthodontie : données utiles.

For the past 30 years X-Ray images have effected a veritable revolution in medical practice. Using them practitioners cannot only make reliable and precise diagnoses when they begin a course of treatment but also accurately follow the progress of therapy. Orthodontics is one of the specialties that has benefited from the innovations in medical radiography. At the same time we have learned more about the risks that the use of ionizing radiation entails and are, accordingly, basing our radiological practice on the ALARA principle ("As Low As Reasonably Achievable"). Even though this concept is embodied in much national and European legislation, practitioners will enhance their daily use of radiology by acquiring an understanding of the scientific basis for ALARA.

[Useful radiological techniques in orthodontics]. / Techniques radiographiques utiles en orthodontie.

Specialists in dento-facial orthopedics have a large range of dental radiological techniques at their disposal to help them in their diagnostic and therapeutic procedures. Peri-apical, occlusal, panoramic, and cephalometric X-Rays are two-dimensional techniques that orthodontists can complement, if necessary, with Multi slices CT scan or Cone Beam Computed Tomography. Orthodontists must apply and respect quality criteria for each type of film in order to derive the best information from every image and to avoid producing artifacts or false images that will reduce their diagnostic value and, accordingly, the service that they render to patients. Practitioners must be willing to spend the few moments it takes to position patients correctly in the radiological apparatus instead of taking multiple views to compensate for failing to scrupulously follow protocols of radiology.

[Indications for radiography in orthodontics and dentofacial orthopedics]. / Indications des examens radiologiques en orthopédie dento-faciale.

The risks associated with the use of ionizing radiation are a constant concern not only for practitioners but also for legislators who have included this ethical rule in the Code of public safety. It proposes reduction of risks by insisting that all X-Rays be taken only when they accord with one of the fundamental principles of X-Ray protection: they must be justified by clear diagnostic need. In direct application of this principle the French government in 2006 published a guide for the management of radiological and dental and stomatological examinations. However, this document dealt only slightly with orthodontics, a field in which the flourishing and burgeoning of radiological techniques made it urgent that regulations for use of X-Rays in orthodontics be brought up to date on an ongoing and permanent basis. The objective of this article is, accordingly, after presentation of a systematic and critical analysis of the lit erature, to propose up-to-date recommendations for proper taking of orthodontic X-Ray films.

[Imaging of temporo-mandibular disorders]. / Imagerie des désordres temporo-mandibulaires.

Dominated for years by standard films (tomographic mouth open and mouth closed X-rays, MRI) radiographs of the TMJ have progressively lost their usefulness to diagnosticians who have progressively increased their reliance on well codified clinical examinations, which suffice in a great majority of cases.The indications for and diagnostic worth of radiological studies and the impact they have on the management of TMJ disorders are today quite low especially when the high cost of procedures like MRI, computerized tomography, and CBCT is taken into account. In this article we discuss the various maladies that dentists might encounter and the situations in which radiological examinations are still indicated.

Trigeminal projections on gustatory neurons of the nucleus of the solitary tract: a double-label strategy using electrical stimulation of the chorda tympani and tracer injection in the lingual nerve.

Taste and sensory information are closely associated and our electrophysiological studies showed a trigeminal modulation of gustatory neurons in the nucleus of the solitary tract (NST). Chorda tympani (CT) and lingual nerves (LN) converge centrally in the rostral subdivision of the NST in hamsters and rats. However, no study has yet revealed the details of this overlap on a same section. We therefore used a double-label strategy to visualize neurons in the NST that receive both trigeminal and gustatory inputs. An anterograde tracer (BDA, Biotinylated Dextran Amine) was applied unilaterally to the cut central end of the LN in male Sprague-Dawley rats. One week later, the ipsilateral CT was electrically stimulated, after which animals were perfused and brainstem sections double-labelled for Fos immunoreactivity of activated NST neurons and BDA labelling of LN afferents. Our results permitted to circumscribe the regional overlap of the trigeminal and CT afferents mainly in the rostral central (RC) subdivision of the gustatory NST. Fos-immunoreactive neurons were observed to be closely apposed by BDA-labelled fibres and terminal boutons. Such varicosities mainly "en passant" were especially present in the RC zone of the nucleus. These observations provide an anatomical substrate for trigemino-gustatory interactions.