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Purpose. The aim of this systematic review is to assess whether the anatomy of mental foramen is precisely evaluable with cone beam computed tomography (CBCT) before implantation in humans. Methods. A systematic review was carried out to evaluate the anatomy of mental foramen (size, position, symmetry, anterior loop, and accessory mental foramen or multiple mental foramina). According to Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines, an electronic search of three databases (Medline, Web of Science, and Cochrane Library) was undertaken until June 2020 and was supplemented by manual searching. Two reviewers will independently perform the processes of study inclusion, data extraction, and quality assessment. Systematic reviews, studies about children, and case reports were excluded. Only studies using CBCT to do preoperative evaluation were selected. Results. From 728 potentially eligible articles, 72 were included in the qualitative analysis and quantitative synthesis. This systematic review provided an assessment of the anatomy of the mental foramen. The mental foramen was located mostly between the two premolars (between 50.4% and 61.95%) or apically to the second premolar (from 50.3% to 57.9%). The mean diameter of the mental foramen was bigger in males than in females; the difference between them could reach 0.62 mm. The anterior loop seemed to be longer in males (between 0.87 ± 1.81 and 7.25 ± 2.02 mm) than in females (between 0.81 ± 1.18 and 6.52 ± 1.63 mm) and with the presence of teeth (from 0.91 ± 1.18 to 2.55 ± 1.28 for dentate people and from 0.25 ± 0.61 to 2.40 ± 0.88 mm for edentate population). The anterior loop and the accessory mental foramina were detected more frequently with CBCT than panoramic X-ray: only between 0.0 and 48.6% AMFs detected with CBCT were also seen with panoramic images. Clinical Significance. The mental foramen (MF) is an important landmark for local anesthesia and surgical and implantology procedures. Its location, morphology, and anatomical variations need to be considered to avoid mental nerve injury. The aim of this review is to evaluate the mental foramen using CBCT through a systematic literature review to improve knowledge of this complex area for the clinician.

The three-dimensional printing of scaffolds is an interesting alternative to the traditional techniques of periodontal regeneration. This technique uses computer assisted design and manufacturing after CT scan. After 3D modelling, individualized scaffolds are printed by extrusion, selective laser sintering, stereolithography, or powder bed inkjet printing. These scaffolds can be made of one or several materials such as natural polymers, synthetic polymers, or bioceramics. They can be monophasic or multiphasic and tend to recreate the architectural structure of the periodontal tissue. In order to enhance the bioactivity and have a higher regeneration, the scaffolds can be embedded with stem cells and/or growth factors. This new technique could enhance a complete periodontal regeneration. This review summarizes the application of 3D printed scaffolds in periodontal regeneration. The process, the materials and designs, the key advantages and prospects of 3D bioprinting are highlighted, providing new ideas for tissue regeneration.

Objective The accuracy of the information incorporated into brackets is a determining factor for the efficacy of torque applied to teeth. The aim of this study was to compare the dimensions of a bracket's slots with the nominal values announced by the manufacturer. Materials and methods A total of 730 maxillary right central brackets manufactured by seven companies (Dentsply Gac, American Orthodontics, Rocky Mountain Orthodontics, GC Orthodontics, 3M Unitek, and Dentaurum) were studied. The sample included 0.018 × 0.025 and 0.022 × 0.028 in., metal and ceramic, conventional and self‐ligating brackets. Images were obtained with an Olympus BX51 optical microscope. Slot dimensions were measured at the base and at the face on both mesial and distal sides using ImageJ software. Data were analyzed using Wilcoxon, sign tests, two‐ and three‐way ANOVA, and Tukey's tests. Intraclass correlation coefficient was employed to assess the intraobserver and interobserver variability. The threshold for statistical significance was p ≤ .05. Results Statistical analysis showed that the slot dimensions of 90% to 97% of studied brackets were significantly different from nominal values. In general, slot size was oversized, with a face size larger than the base size. Comparison between mesial and distal sides showed that up to 45% of the brackets were significantly asymmetrical. The manufacturer had a significant effect for base and face widths (p = .0001) and for length (p = .003). Conclusion This study shows that a large proportion of measured brackets displays dimensional inaccuracies when compared with stated values. Clinically, the slot oversize and the divergence of slot walls cause an increase of wire‐slot play, inducing a loss of torque control. Practitioners cannot fully trust the precision of used appliances and should be aware that adjustments could be needed in the finishing stages of the treatment.

International audience; A mechanical analysis of different architectures of scaffolds processed by selective laser melting (SLM) of 316L stainless steel powder is proposed. Experimental compression tests of scaffolds obtained with different SLM parameters are compared with FEM computations. Identification of the mechanical behavior law parameters of the constitutive material of the scaffolds is made. It is shown that for non post heat treated scaffolds, the identified parameters on a specific architecture are not transferable to predict the compression behavior of an other architecture.

Colloque EUROMECH Bone remodeling: multiscale mechanical models and multiphysical aspects, Nancy, France, 15 May 2018 - 19 May 2018, In recent years, research in bone surgery has focused on developing strategies to accelerate bone regeneration. The major challenge of these researches is to repair large bone defects. Bone grafting technique is the gold standard to fill and heal these kind of defects. However, the mechanical behavior recovering of the newly formed bone, as the regeneration process takes place, remains still poorly understood. Only few studies actually address bone regeneration microstructure as regard to the mechanical properties induced. Recently, Hoerth and al.1 investigated the effect of different mechanical situations during bone healing of a rat femoral osteotomy model onto the microstructure developed and the mechanical properties induced thanks to nanoindentation. However, mechanical investigations have been carried out exclusively on post-regenerated specimen, i.e. on the completely reconstructed bones, and the related observed spatial-resolved mechanical properties gradient could not be solved.To overcome this lack of understanding, this work is leaning on mechanically characterize the bone regeneration process in the tissue engineering frameworks related to bone substitute isolated implantation (inside a 3-mm diameter surgically created defect). This study particularly highlights the distribution of mechanical stresses induced by the healing process through mechanical state mapping in various regeneration levels thanks to rat calvarias samples harvested at different regeneration stages (2, 4, 6 and 8 weeks after implantation). In situ tensile testing under SAXS/WAXS (Small- and Wide- Angle X-ray Scattering) synchrotron µ-beam (P03 beamline-PETRA III- Hamburg) have been achieved to spatially resolve the strain/stress response of collagen fibers and mineral part (hydroxyapatite - Hap) of bone architecture, respectively. In the light of those results, a complete expertise is carried out onto biological processes occurring at the microscopic level involved in the bone regeneration thanks to their correlation to various microstructural analysis (histological or micro-tomography observations).

International audience; Our current Western societies tend to consider the teeth as a purely cosmetic and food item, the point of considering their alteration and transformation over time as almost exclusively resulting from food and occlusal pathologies or accidental trauma. But if the variety of tools at our disposition by technology sometimes leads us to consider our hands even as too vulnerable, teeth always served industrial uses, such as cutting tool, press or gripping means. From dressmaker to kodyak, we build here a small inventory of these practices and their consequences .; Nos sociétés occidentales actuelles tendent à considérer les dents comme un élément purement alimentaire et cosmétique, au point de considérer leur altération et leur transformation au cours du temps comme résultant quasi-exclusivement de l'alimentation et de pathologies occlusales, voire de traumatismes accidentels. Or, si la variété des outils mis à notre disposition par la technologie nous amène parfois à considérer nos mains même comme trop fragiles, les dents de tout temps ont servi à des usages industriels, comme outil tranchant, presse ou moyen de préhension. De la couturière au kodyak, nous dressons ici un petit inventaire de ces usages et de leurs conséquences.

International audience; Background: Coronary stents participate to limit cardiovascular death but are associated with some complications. Matching stent biomechanical characteristics with specific coronary lesions could limit these complications.Objectives: Development of a standardized and global bench test protocol and evaluation of most currently used coronary stents to improve stent choice in cathlab.Materials: We evaluated biomechanical characteristics of coronary stents (AbsorbTM-ABBOTT (R), Xience AlpineTM-ABBOTT (R), Resolute IntegrityTM-MEDTRONIC (R), Resolute OnyxTM-MEDTRONIC (R), OrsiroTM-BIOTRONIK (R), SynergyTM-BOSTON SCIENTIFIC (R), OptimaxTM-HEXACATH (R)) in an in vitro study: radial elastic recoil, foreshortening, crimped stent with balloon flexibility and deployed stent flexibility. We also evaluated maximal resistance, elastic strength limit and elastic deformation limit for radial and longitudinal compression. Stentswere deployed in a saline solution at 37+/-0.5 °C. 9 stents were used to evaluate elastic recoil and foreshortening. Then, 3 among them were used to evaluate radial resistance between parallel plates, 3 were used to evaluate longitudinal resistance and 3 others were used to evaluate deployed stent bending stiffness. Before stent inflation 3 stents, among the 9 devices dedicated to biomechanical evaluation, were used to evaluate the uninflated stent with balloon bending stiffness. For a maximum comparability between stent models, we chose the most used stent size in our clinical practice (3.0 mm diameter and the nearest to 20 mm length). For these evaluations, all devices were inflated with them own balloon, at nominal pressure, according to manufacturer's recommendations. Nominal pressure was maintained for 30 seconds. We studied coating with field emission gun scanning electron microscope after POT-SIDE-POT (PSP) simulation to evaluate coating resistance to angioplasty. Bifurcation performances were evaluated by microcomputed tomography imaging of PSP stented silicon bifurcation models. Statistical analyses were performed using XLStats 2017 (Addinsoft).Results: Elastic recoil, deployed stent exibility and crimped stent flexibility were signicantly different between groups (all p < 0.0001); as were radial and longitudinal maximum resistance (p < 0.0001). SynergyTM, OrsiroTM and Xience AlpineTM had the lowest elastic recoil. SynergyTM and Resolute OnyxTM were the most exible. OptimaxTM had the highest radial and longitudinal resistance. Coating lesions after PSP were not signicantly different, excepted for OptimaxTM which had no coating lesion. In bifurcation model, side branch ostium coverage and malapposed strut ratio were signicantly different between groups (respectively, p = 0.01 and p = 0.004). Strut fractures were founded only in AbsorbTM.Conclusion: Currently used stents have very different biomechanical and bifurcation performance proles. Their choice had to be adapted to each coronary lesion particularity to improve coronary interventions results.