Dental sleep medicine education among undergraduate dental students in France.

INTRODUCTION: Dental sleep medicine (DSM) is an emerging discipline that studies the oral and maxillofacial causes and consequences of sleep-related problems. DSM is of upmost importance given the major medical challenge it represents. Therefore, to verify whether the future generation of dentists would be ready to face this challenge, the main objective of this study was to assess the degree of involvement of the French dental schools in teaching DSM at the undergraduate level. MATERIALS AND METHODS: All 16 dental schools in France were asked to participate in the study by answering to an online survey concerning the DSM curriculum during the 2018-2019 academic year. The survey was addressed to the head of the dental school and/or to relevant course coordinators and contained 10 questions related to the type, content and amount of DSM teaching to undergraduate dental students. RESULTS: Nine of the 16 (56.2%) French dental schools responded to the questionnaire. All these nine reported the inclusion of DSM in their undergraduate curriculum. The total average hours dedicated to teaching DSM was 5.6 h (SD 4.2; range 1-15 h). Seven of the 9 dental schools spent most of their DSM curriculum teaching time in the fifth year. All of them reviewed obstructive sleep apnoea and sleep-related bruxism and covered some topics related to therapies for sleep-related breathing disorders, such as the use of oral appliance. CONCLUSION: The results of this survey showed that, although the average hourly volume is relatively high, the DSM teaching in French dental schools appeared to be non-standardised, heterogeneous and often lacunar. It is therefore essential to develop a common curriculum and implement it in all dental schools to provide undergraduate students a comprehensive and updated teaching in DSM.

The effect of masks on the visual preference for faces in the first year of life.

To prevent the spread of COVID-19, face masks were mandatory in many public spaces around the world. Since faces are the gateway to early social cognition, this raised major concerns about the effect face masks may have on infants' attention to faces as well as on their language and social development. The goal of the present study was to assess how face masks modulate infants' attention to faces over the course of the first year of life. We measured 3, 6, 9, and 12-month-olds' looking behavior using a paired visual preference paradigm under two experimental conditions. First, we tested infants' preference for upright masked or unmasked faces of the same female individual. We found that regardless of age, infants looked equally long at the masked and unmasked faces. Second, we compared infants' attention to an upright masked versus an inverted masked face. Three- and 6-month-olds looked equally long to the masked faces when they were upright or inverted. However, 9- and 12-month-old infants showed a novelty preference for the inverted masked face. Our findings suggest that more experience with faces, including masked faces, leads to efficient adaptations of infants' visual system for processing impoverished social stimuli, such as partially occluded faces.

Structural modifications induced in dentin by femtosecond laser.

The structural and chemical modifications induced in dentin by ultrafast laser ablation were studied. The laser experiments were performed with a Yb:KYW chirped-pulse-regenerative amplification laser system (560-fs pulse duration, 1030-nm radiation wavelength), fluences in the range 2 to 14 ?? J / cm 2 , 1-kHz pulse repetition rate, and 5 - mm / s scanning speed. The ablation surfaces were characterized by scanning electron microscopy and Fourier transform infrared spectroscopy. The ablation surfaces produced with 2 ?? J / cm 2 presented an irregular morphology with exposed dentinal tubules and no evidence of thermal effects. For 7 and 14 ?? J / cm 2 , the ablation surfaces were covered by a layer of redeposited ablation debris, consisting mainly of amorphous calcium phosphate. This layer is weakly adherent to the underlying tissue and can be easily removed by ultrasonication, revealing a surface with a morphology similar to the one obtained with 2 ?? J / cm 2 . The constitution of the dentin ablation surfaces is similar to the constitution of pristine dentin, showing that, within this fluence range, the laser treatment does not significantly modify the structure and constitution of dentin. The results achieved suggest an ablation mechanism where collagen is preferentially decomposed by the laser radiation, reducing the tissue cohesive strength and leading, ultimately, to its ablation.

Femtosecond laser ablation of enamel.

The surface topographical, compositional, and structural modifications induced in human enamel by femtosecond laser ablation is studied. The laser treatments were performed using a Yb:KYW chirped-pulse-regenerative amplification laser system (560 fs and 1030 nm) and fluences up to 14 J/cm2. The ablation surfaces were studied by scanning electron microscopy, grazing incidence x-ray diffraction, and micro-Raman spectroscopy. Regardless of the fluence, the ablation surfaces were covered by a layer of resolidified material, indicating that ablation is accompanied by melting of hydroxyapatite. This layer presented pores and exploded gas bubbles, created by the release of gaseous decomposition products of hydroxyapatite (CO2 and H2O) within the liquid phase. In the specimen treated with 1-kHz repetition frequency and 14 J/cm2, thickness of the resolidified material is in the range of 300 to 900 nm. The micro-Raman analysis revealed that the resolidified material contains amorphous calcium phosphate, while grazing incidence x-ray diffraction analysis allowed detecting traces of a calcium phosphate other than hydroxyapatite, probably ß-tricalcium phosphate Ca3(PO4)2, at the surface of this specimen. The present results show that the ablation of enamel involves melting of enamel's hydroxyapatite, but the thickness of the altered layer is very small and thermal damage of the remaining material is negligible.

CRMP5 Controls Glioblastoma Cell Proliferation and Survival through Notch-Dependent Signaling.

Collapsin response mediator protein 5 (CRMP5) belongs to a family of five cytosolic proteins that play a major role in nervous system development. This protein was first described in cancer-induced autoimmune processes, causing neurodegenerative disorders (paraneoplastic neurologic syndromes). CRMP5 expression has been reported to serve as a biomarker for high-grade lung neuroendocrine carcinomas; however, its functional roles have not been examined in any setting of cancer pathophysiology. In this study, we report two different CRMP5 expression patterns observed in human glioblastoma (GBM) biopsies that establish connections between CRMP5 expression, Notch receptor signaling, and GBM cell proliferation. We demonstrated that elevated CRMP5 promotes Notch receptor expression and Akt activation in human tumor cell lines, GBM stem cells, and primary tumor biopsies. We have shown that the high CRMP5 and Notch expression in GBM xenograft is related to stem cells. This suggests that high CRMP5 expression pattern in GBM biopsies encompasses a subset of stem cells. Mechanistically, CRMP5 functioned by hijacking Notch receptors from Itch-dependent lysosomal degradation. Our findings suggest that CRMP5 serves as a major mediator of Notch signaling and Akt activation by controlling the degradation of the Notch receptor, with implications for defining a biomarker signature in GBM that correlates with and may predict patient survival.

Temporal pulse shaping: a key parameter for the laser welding of dental alloys.

This study aims to describe the effect of pulse shaping on the prevention of internal defects during laser welding for two dental alloys mainly used in prosthetic dentistry. Single spot, weld beads, and welds with 80 % overlapping were performed on Co-Cr-Mo and Pd-Ag-Sn cast plates with a pulsed neodymium-doped yttrium aluminum garnet (Nd:YAG) laser. A specific welding procedure using adapted parameters to each alloy was completed. All the possibilities for pulse shaping were tested: (1) the square pulse shape as a default setting, (2) a rising edge slope for gradual heating, (3) a falling edge slope to slow the cooling process, and (4) a combination of rising and falling edges. The optimization of the pulse shape is supposed to produce defect-free welds (crack, pores, voids). Cross-section SEM observations and Vickers microhardness measurements were made. Pd-Ag-Sn was highly sensitive to hot cracking, and Co-Cr-Mo was more sensitive to voids and small porosities (sometimes combined with cracks). Using a slow cooling ramp allowed a better control on the solidification process for those two alloys always preventing internal defects. A rapid slope should be preferred for Co-Cr-Mo alloys due to its low-laser beam reflectivity. On the opposite, for Pd-Ag-Sn alloy, a slow rising slope should be preferred because this alloy has a high-laser beam reflectivity.

Effect of periodontal treatment on the clinical parameters of patients with rheumatoid arthritis: study protocol of the randomized, controlled ESPERA trial.

BACKGROUND: Rheumatoid arthritis (RA) is a chronic inflammatory disorder that leads to joint damage, deformity, and pain. It affects approximately 1% of adults in developed countries. Periodontitis is a chronic oral infection, caused by inflammatory reactions to gram-negative anaerobic bacteria, and affecting about 35 to 50% of adults. If left untreated, periodontitis can lead to tooth loss. A significant association has been shown to exist between periodontitis and RA in observational studies. Some intervention studies have suggested that periodontal treatment can reduce serum inflammatory biomarkers such as C-reactive protein, or erythrocyte sedimentation rate. We hypothesize that periodontitis could be an aggravating factor in patients with RA, and that its treatment would improve RA outcomes. The aim of this clinical trial is to assess the effect of periodontal treatment on the biological and clinical parameters of patients with RA. METHODS/DESIGN: The ESPERA (Experimental Study of Periodontitis and Rheumatoid Arthritis) study is an open-label, randomized, controlled trial. Subjects with both RA and periodontitis will be recruited at two university hospitals in southwestern France. In total, 40 subjects will be randomized into two arms (intervention and control groups), and will be followed up for 3 months. Intervention will consist of full-mouth supra-gingival and sub-gingival non-surgical scaling and root planing, followed by systemic antibiotic therapy, local antiseptics, and oral hygiene instructions. After the 3-month follow-up period, the same intervention will be applied to the subjects randomized to the control group.The primary outcome will be change of in Disease Activity Score in 28 Joints (DAS28) at the end of the follow-up period. Secondary outcomes will be the percentages of subjects with 20%, 50%, and 70% improvement in disease according to the American College of Rheumatology criteria. Health-related quality of life assessments (the Health Assessment Questionnaire and the Geriatric Oral Health Assessment Index) will also be compared between the two groups. DISCUSSION: Evidence-based management of potential aggravating factors in subjects with active RA could be of clinical importance, yet there are few randomized controlled trials on the effect of periodontal treatment on the clinical parameters of RA. The ESPERA trial is designed to determine if non-surgical periodontal treatment could improve clinical outcomes in patients with active RA, and the quality of life of these patients. TRIAL REGISTRATION: The ESPERA Trial was registered in Current Controlled Trials [ISRCTN79186420] on 2012/03/20. The trial started recruiting on 2012/03/06.

T-cell activation by treatment of cancer patients with EMD 521873 (Selectikine), an IL-2/anti-DNA fusion protein.

BACKGROUND: EMD 521873 (Selectikine or NHS-IL2LT) is a fusion protein consisting of modified human IL-2 which binds specifically to the high-affinity IL-2 receptor, and an antibody specific for both single- and double-stranded DNA, designed to facilitate the enrichment of IL-2 in tumor tissue. METHODS: An extensive analysis of pharmacodynamic (PD) markers associated with target modulation was assessed during a first-in-human phase I dose-escalation trial of Selectikine. RESULTS: Thirty-nine patients with metastatic or locally advanced tumors refractory to standard treatments were treated with increasing doses of Selectikine, and nine further patients received additional cyclophosphamide. PD analysis, assessed during the first two treatment cycles, revealed strong activation of both CD4+ and CD8+ T-cells and only weak NK cell activation. No dose response was observed. As expected, Treg cells responded actively to Selectikine but remained at lower frequency than effector CD4+ T-cells. Interestingly, patient survival correlated positively with both high lymphocyte counts and low levels of activated CD8+ T-cells at baseline, the latter of which was associated with enhanced T-cell responses to the treatment. CONCLUSIONS: The results confirm the selectivity of Selectikine with predominant T-cell and low NK cell activation, supporting follow-up studies assessing the clinical efficacy of Selectikine for cancer patients.

Microstructure and mechanical properties of surface treated cast titanium with Nd:YAG laser.

OBJECTIVE: To investigate the effect of laser surface treatment of cast titanium alloy on microstructure and mechanical properties. METHODS: Dumbbell- and plate-shaped cast titanium specimens were prepared for mechanical testing and microstructure analysis. After the cast surfaces of each specimen were laser-treated using a dental Nd:YAG laser machine at 240 V and 300 V with and without argon gas shielding, tensile testing and microstructure analysis were conducted. Hardness depth profiles were also made from the cross-section of laser-treated cast specimens. Microstructural and chemical analysis were performed by means of the SEM, XRD, AES and WDS. RESULTS: The results of tensile testing and Vickers hardness depth profiling showed that laser treatment improved the mechanical properties. Bulk microstructure of as-cast titanium was mainly composed of α-grains with acicular and widmanstatten patterns. The laser melted zone was characterized by columnar beta grains. When the emission voltage of laser increased to 300V, a larger grain size was promoted. The XRD analysis indicated that the beta phase formation was clearly noticeable after laser surface treatment. Supplementary marked peaks of the TiO, TiO(2) and Ti(2)N were detected without argon gas shielding. When argon shielding gas was used, the presence of titanium oxide was significantly reduced and the peaks of titanium nitride disappeared. SIGNIFICANCE: Laser treatment on cast titanium surfaces showed significant enhancement of mechanical properties and modification of microstructures, and therefore could produce reliable titanium metal frameworks for dental prostheses.

Enhanced susceptibility of T lymphocytes to oxidative stress in the absence of the cellular prion protein.

The cellular prion glycoprotein (PrP(C)) is ubiquitously expressed but its physiologic functions remain enigmatic, particularly in the immune system. Here, we demonstrate in vitro and in vivo that PrP(C) is involved in T lymphocytes response to oxidative stress. By monitoring the intracellular level of reduced glutathione, we show that PrP(-/-) thymocytes display a higher susceptibility to H(2)O(2) exposure than PrP(+/+) cells. Furthermore, we find that in mice fed with a restricted diet, a regimen known to increase the intracellular level of ROS, PrP(-/-) thymocytes are more sensitive to oxidative stress. PrP(C) function appears to be specific for oxidative stress, since no significant differences are observed between PrP(-/-) and PrP(+/+) mice exposed to other kinds of stress. We also show a marked evolution of the redox status of T cells throughout differentiation in the thymus. Taken together, our results clearly ascribe to PrP(C) a protective function in thymocytes against oxidative stress.

Proposals for optimization of laser welding in prosthetic dentistry.

This paper points out each key parameter involved in laser welding and discusses the parameters' effects on weld microstructure and defects detected inside the weld. Solutions are proposed to adjust the parameters to provide an optimal dental assembly. Metallurgical effects as well as defects are briefly discussed. A welding procedure adapted to different compositions of dental alloys is proposed.

Intraoral metal laser welding: a case report.

The possibility of laser welding of dental prostheses offers great advantages: first, the operator has the possibility of welding on the master model, which decreases the number of passages and thus the possibility of errors and damage, and secondly, the patient attends only a few sessions, and, due to the possibility of fixing the damaged prostheses, there is no need to resort to the technician's laboratory. In a previous study we described the experimental phases of intraoral welding, from the in vitro model on animal jaws with evaluations of the temperature variations during welding through thermal chamber and type K thermocouples. In this study we describe the intraoral welding in vivo on human subjects by using, as in the previous study, a fibre-delivered neodymium:yttrium-aluminum-garnet (Nd:YAG) laser. The in vivo phase allowed a restored prosthesis to be positioned and intraorally welded in the upper central sector with optimal results both in patient's comfort and in aesthetic effects. This first in vivo test confirmed that the use of a laser technique for the intraoral welding of metal prostheses is possible, with no particular problems and risks for the biological structures close to the welding zone.

Welding in the dental office by fiber-delivered laser: a new technique.

OBJECTIVE: The aim of this study is to demonstrate the ability of dentists to weld different metals during daily practice using a fiber-delivered laser normally used for dental surgery, and to evaluate the possibilities offered by this new technique. BACKGROUND DATA: Laser welding is a common technique that has long been used in dental technician laboratories. It has many advantages over conventional techniques: it may be applied directly to master casts, and it avoids damage to the acrylic or ceramic portions close to the welded area. In addition, it may be applied on different types of metallic alloys, and it may provide a stronger attachment than other more traditional techniques. The cost, size, and limited flexibility of laser transmission systems using fixed lenses have restricted their use to dental technician laboratories. MATERIALS AND METHODS: The authors detail their experience with welding using an Nd:YAG fiberoptic-delivered laser that is normally used for dental therapy. RESULTS: This work describes some clinical cases that demonstrate the ease of use of this technique to weld broken appliances for both prosthetic and orthodontic therapy. CONCLUSION: Dentists using this technique can carry out immediate restoration of metallic fixed, removable, and orthodontic broken prostheses in their own offices, thus reducing the time needed for such repairs.