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Purpose Processed nerve allografts (PNA) are an alternative to nerve autografts to reconstruct the inferior alveolar nerve (IAN) when it is damaged. The purpose of this study was to report the results of IAN reconstruction using PNA in the context of aggressive benign mandibular pathology. Material and method A systematic literature review was performed according to the Preferred Reporting Items for Systematic reviews and Meta-Analysis (PRISMA) statement through the MEDLINE (Pubmed) and SCOPUS (Elsevier) databases. Studies concerning reconstructive surgeries of IAN by PNA, performed at the same time as the surgical resection of the benign pathologies of the mandible were included. The following data were analyzed: gender and patient age, cause of mandibular resection, graft dimensions, sensory recovery at least 6 months after surgery according to the MRC scale, and adverse events related to the intervention. Results The initial search yielded 290 studies and 5 were included in the final review. A total of 33 patients underwent 36 IAN reconstructions; 14 patients were female (42.4%) and mean age was 30 years old. The mean length of graft used was 64.0 ± 9.1 mm. The most common pathology that led to nerve resection was ameloblastoma (52%). Among the reconstructions for which follow-up data were available, functional sensory recovery occurred in 92.9% of cases. Conclusion PNA are a reliable, safe, and effective alternative to nerve autografts for the rehabilitation of the IAN with 92.9% of functional recovery according to the reported literature, avoiding any comorbidity associated with the use of a donor site.

Expert determination of the third molar maturity index (I3M) constitutes one of the most common approaches for dental age estimation. This work aimed to investigate the technical feasibility of creating a decision-making tool based on I3M to support expert decision-making. Methods: The dataset consisted of 456 images from France and Uganda. Two deep learning approaches (Mask R-CNN, U-Net) were compared on mandibular radiographs, leading to a two-part instance segmentation (apical and coronal). Then, two topological data analysis approaches were compared on the inferred mask: one with a deep learning component (TDA-DL), one without (TDA). Regarding mask inference, U-Net had a better accuracy (mean intersection over union metric (mIoU)), 91.2% compared to 83.8% for Mask R-CNN. The combination of U-Net with TDA or TDA-DL to compute the I3M score revealed satisfying results in comparison with a dental forensic expert. The mean ± SD absolute error was 0.04 ± 0.03 for TDA, and 0.06 ± 0.04 for TDA-DL. The Pearson correlation coefficient of the I3M scores between the expert and a U-Net model was 0.93 when combined with TDA and 0.89 with TDA-DL. This pilot study illustrates the potential feasibility to automate an I3M solution combining a deep learning and a topological approach, with 95% accuracy in comparison with an expert.

A digital dental technique is described for registering functional borders of immediate complete dentures, by using an intraoral scanner, a dental computer-aided design software program, and a peripheral custom tray. This article also illustrates how to virtually match the recorded information in order to transform the initial intraoral scan into definitive digital scans.

Objective Clasps of removable partial dentures (RPDs) often suffer from fatigue stress that leads to plastic deformation, loss of retention, and RPD failure. Recently, computer-based technologies were proposed to optimize clasp geometry design. The objective of this study was to create an analytic model of I-bar clasps for computer-aided design (CAD)-RPD. Methods The analytical model based on mechanical laws was established to simulate I-bar clasp retention, and optimize its design. The model considered the lengths of the vertical ( L 1 ) and horizontal (L2) arms of the I-bar as well as the radius (r) of its half-round cross-section. The analytical model was validated with mechanical experiments evaluating the retention of cobalt–chromium (Co–Cr) clasps in vitro and compared with finite element analysis (FEA). Results The analytical model was in good agreement with the mechanical experiments and FEA, and showed that I-bar clasp design could provide optimal mechanical performance as long as the length of arms (L1 and L2) do not exceed 6 mm. Clasps with L1 > 8 mm and L2 > 9 mm presented stress values exceeding the fatigue limit of Co–Cr. The proposed solution was to increase the radius of I-bar to conserve the initial mechanical performance of Co–Cr. Significance Co–Cr I-bar clasps perform best on teeth with reduced mesiodistal dimensions (canine and premolar), and their designs could be optimized to prevent stress from reaching the yield strength and the fatigue failure limit.

Purpose of Review The aim of this case report was to illustrate the clinical procedure integrating augmented reality (AR) for complex patient cases requiring full mouth rehabilitation. Recent Findings The introduction of AR technology to the fields of medicine and dentistry has led to numerous applications in education, surgery, and esthetics. Recently, a new AR software was introduced in esthetic dentistry which allows for real-time smile projection and thus improves communication with patients and the dental laboratory. Summary The presented case shows a patient with multiple missing teeth, diastemata, and an impaired masticatory and phonetic ability. After reconstruction of the posterior zone, the AR software was used for the conception of the esthetic zone, integrating the patient into the decision-making process. The result was an esthetic rehabilitation applying palatal and buccal veneers which corresponded to the chosen AR design. The patient appreciated the opportunity to pre-visualize a possible final outcome in an interactive way which increased his confidence in the chosen treatment. Further studies are needed to assess the precision and reproducibility of the described protocol.

The Script Concordance Test (SCT) is an educational tool that aims to assess the ability to interpret medical information under conditions of uncertainty. It is widely used and validated in health education, but almost unknown in dentistry. Based on authentic clinical problem-solving situations, it allows to assess clinical reasoning that experienced health workers develop over the years. A specific scoring system, dedicated to SCT, considers the variability of responses of practitioners in the same clinical situations. Finally, the scores generated by SCT reflect the respondents' ability to interpret clinical data compared to experienced clinicians. This article aims to familiarise the dental educators' community with SCT construction, optimisation and its possible applications.

Clinical performance of osseointegrated implants could be compromised by the medications taken by patients. The effect of a specific medication on osseointegration can be easily investigated using traditional systematic reviews. However, assessment of all known medications requires the use of evidence mapping methods. These methods allow assessment of complex questions, but they are very resource intensive when done manually. The objective of this study was to develop a machine learning algorithm to automatically map the literature assessing the effect of medications on osseointegration. Datasets of articles classified manually were used to train a machine-learning algorithm based on Support Vector Machines. The algorithm was then validated and used to screen 599,604 articles identified with an extremely sensitive search strategy. The algorithm included 281 relevant articles that described the effect of 31 different drugs on osseointegration. This approach achieved an accuracy of 95%, and compared to manual screening, it reduced the workload by 93%. The systematic mapping revealed that the treatment outcomes of osseointegrated medical devices could be influenced by drugs affecting homeostasis, inflammation, cell proliferation and bone remodeling. The effect of all known medications on the performance of osseointegrated medical devices can be assessed using evidence mappings executed with highly accurate machine learning algorithms.

Tissue engineering-based endodontic therapies, designed to regenerate the dental pulp (DP) in the devitalised endodontic space, have been proposed to improve tooth longevity compared to conventional root-filling therapies. Their aim is to restore tooth vitality and major DP functions necessary to maintain tooth health such as immunosurveillance, sensitivity and healing/repair/regenerative capacities. Several formulations based on the use of fibrin, the main component of the blood clot matrix, recently gave valuable results in the regeneration of the human DP. This review describes recent fibrin-based scaffolds designed for that purpose. After having presented the various strategies for DP regeneration, the main fibrin-based scaffolds reported so far for clinical use in endodontics were reviewed. Particular emphasis was given to hydrogel devices that may be improved by incorporation of bioactive molecules that stimulate vascularisation and tissue neoformation or provide antibacterial properties. Data indicate that fibrin-based scaffolds constitute a highly favourable environment for mesenchymal stem cells, which is maintained upon functionalisation. Additional knowledge is needed to understand how fibrin and functionalising agents affect adhesion, survival, proliferation, migration and differentiation of cells incorporated in the scaffold or which will colonise it from neighbouring host tissues. This knowledge is needed to adapt the hydrogel formulation for various clinical conditions.

Purpose To design a checklist in order to reduce the frequency of reconstructive preventable errors (PE) performed by undergraduate dental students at McGill University. Materials and methods The most common PE occurring at a university dental clinic were identified by three reviewers analyzing the refunded cases, and used to create a preliminary checklist. This checklist was then validated by a panel of dental educators to produce a finalized 20-item checklist. The 20-question checklist was then submitted to students in a cross-sectional survey-based study to evaluate its relevance to undergraduate clinical education needs. Results As many as 81% of students reported to have forgotten at least one item of the checklist during care of their last patient, and the most forgotten checklist items corresponded to the pretreatment stage. The students also reported that 17 of the 20 items in the checklist were relevant to a considerable extent or highly relevant. Conclusion Common PE identified in the undergraduate clinic could be used to create a checklist of relevant items designed to reduce errors made by students and practitioners performing prosthodontic and reconstructive treatments. However, further studies are required to evaluate the implementation and efficiency of the checklist.

Pulpitis is the inflammatory response of the dental pulp to a tooth insult, whether it is microbial, chemical, or physical in origin. It is traditionally referred to as reversible or irreversible, a classification for therapeutic purposes that determines the capability of the pulp to heal. Recently, new knowledge about dental pulp physiopathology led to orientate therapeutics towards more frequent preservation of pulp vitality. However, full adoption of these vital pulp therapies by dental practitioners will be achieved only following better understanding of cell and tissue mechanisms involved in pulpitis. The current narrative review aimed to discuss the contribution of the most significant experimental models developed to study pulpitis. Traditionally, in vitro two (2D)- or three (3D)-dimensional cell cultures or in vivo animal models were used to analyse the pulp response to pulpitis inducers at cell, tissue or organ level. In vitro, 2D cell cultures were mainly used to decipher the specific roles of key actors of pulp inflammation such as bacterial by-products, pro-inflammatory cytokines, odontoblasts or pulp stem cells. However, these simple models did not reproduce the 3D organisation of the pulp tissue and, with rare exceptions, did not consider interactions between resident cell types. In vitro, tissue/organ-based models were developed to better reflect the complexity of the pulp structure. Their major disadvantage is that they did not allow the analysis of blood supply and innervation participation. On the contrary, in vivo models have allowed researchers to identify key immune, vascular and nervous actors of pulpitis and to understand their function and interplay in the inflamed pulp. However, inflammation was mainly induced by iatrogenic dentine drilling associated with simple pulp exposure to the oral environment or stimulation by individual bacterial by-products for short periods. Clearly, these models did not reflect the long and progressive development of dental caries. Lastly, the substantial diversity of the existing models makes experimental data extrapolation to the clinical situation complicated. Therefore, improvement in the design and standardisation of future models, for example by using novel molecular biomarkers, databased models and artificial intelligence, will be an essential step in building an incremental knowledge of pulpitis in the future.

Albers-Schönberg disease is a rare bone syndrome characterized by increased bone density and infectious complications after dental extraction or minor surgery. The prosthodontic management of such edentulous patients with osteomyelitis is very challenging and requires special strategies due to a high risk of failure and worsening of the condition. This clinical report describes the rehabilitation of a 31-year-old edentulous woman presenting with Albers-Schönberg disease and secondary chronic osteomyelitis, maxillary hypoplasia, compromised oral conditions, temporomandibular disorders, and psychologic distress. The treatment included mandibulectomy and removable prostheses. A crucial element for the successful long-term treatment and quality of life improvement observed in this patient was the 1-year transitional phase with interim dentures and frequent follow-up appointments. The complications and management proposed during a 10-year follow-up are presented.

International audience; Background: The present study aimed to classify the relative contributions of four biomechanical factors—the root-end filling material, the apical preparation, the root resection length, and the bone height—on the root stresses of the resected premolar. Methods: A design of experiments approach based on a defined subset of factor combinations was conducted to calculate the influence of each factor and their interactions. Sixteen finite element models were created and analyzed using the von Mises stress criterion. The robustness of the design of experiments was evaluated with nine supplementary models. Results: The current study showed that the factors preparation and bone height had a high influence on root stresses. However, it also revealed that nearly half of the biomechanical impact was missed without considering interactions between factors, particularly between resection and preparation. Conclusions: Design of experiments appears to be a valuable strategy to classify the contributions of biomechanical factors related to endodontics. Imagining all possible interactions and their clinical impact is difficult and can require relying on one’s own experience. This study proposed a statistical method to quantify the mechanical risk when planning apicoectomy. A perspective could be to integrate the equation defined herein in future software to support decision-making.

Oral health is grounded in the United National (UN) 2030 Agenda for Sustainable Developement and its 17 Goals (SDGs), in particular SDG 3 (Ensure healthy lives and promote well-being for all at all ages). The World Health Organization (WHO) Global Strategy on Oral Health calls for prioritizing environmentally sustainable and less invasive oral health care, and planetary health. Artificial Intelligence (AI) has the potential to power the next generation of oral health services and care, however its relationship with the broader UN and WHO concepts of sustainability remains poorly defined and articulated. We review the double-edged relationships between AI and oral health, to suggest actions that promote a sustainable deployment of AI for oral health.Concepts regarding AI, sustainability and sustainable development were identified and defined. A review of several double-edged relationship between AI and SDGs were exposed for the field of Oral Health.Medline and international declarations of the WHO, the UN and the World Dental Federation (FDI) were screened.One the one hand, AI may reduce transportation, optimize care delivery (SDG 3 "Good Health and Well-Being", SDG 13 "Climate Action"), and increase accessibility of services and reduce inequality (SDG 10 "Reduced Inequalities", SDG 4 "Quality Education"). On the other hand, the deployment, implementation and maintenance of AI require significant resources (SDG 12 "Responsible Consumption and Production"), and costs for AI may aggravate inequalities. Also, AI may be biased, reinforcing inequalities (SDG 10) and discrimination (SDG 5), and may violate principles of security, privacy and confidentiality of personal information (SDG 16).Systematic assessment of the positive impact and adverse effects of AI on sustainable oral health may help to foster the former and curb the latter based on evidence.If sustainability imperatives are actively taken into consideration, the community of oral health professionals should then employ AI for improving effectiveness, efficiency, and safety of oral healthcare; strengthen oral health surveillance; foster education and accessibility of care; ensure fairness, transparency and governance of AI for oral health; develop legislation and infrastructure to expand the use of digital health technologies including AI.

This scoping review aimed to present an overview of the literature on communication tools in esthetic dentistry. A variety of communication tools have been proposed to include patients in the shared decision-making (SDM) workflow. Only little is known about implementing communication tools in dentistry and their impact on patient communication and patient satisfaction. A systematic literature search was performed in Medline, Embase, Cochrane, and World of Science to identify if communication tools have an impact on patient satisfaction.The search included studies from January 1, 2000 to March 3, 2020 published in English, focusing on patient communication tools and patient satisfaction in esthetic dentistry.Out of 6678 records, 53 full-texts were examined. Ten studies were included. Data of the included studies were extracted systematically and subsequently analyzed. All studies found that patient communication utilizing specific communication tools positively impacted either patient satisfaction, patient-dentist relationship, information retention, treatment acceptance, quality of care or treatment outcome.Additional communication tools besides conventional verbal communication are able to enhance patient satisfaction, improve quality of care and establish a better patient-dentist relationship. It seems essential to further develop standardized communication tools for SDM in dental medicine, which will allow the comparison of research on this topic.This scoping review shows the importance of patient involvement in the decision-making process for improved patient satisfaction with esthetic dental treatments. With an increased implementation of communication tools, patient satisfaction and SDM may further improve in the future.

The dental practice has largely evolved in the last 50 years following a better understanding of the biomechanical behaviour of teeth and its supporting structures, as well as developments in the fields of imaging and biomaterials. However, many patients still encounter treatment failures; this is related to the complex nature of evaluating the biomechanical aspects of each clinical situation due to the numerous patient-specific parameters, such as occlusion and root anatomy. In parallel, the advent of cone beam computed tomography enabled researchers in the field of odontology as well as clinicians to gather and model patient data with sufficient accuracy using image processing and finite element technologies. These developments gave rise to a new precision medicine concept that proposes to individually assess anatomical and biomechanical characteristics and adapt treatment options accordingly. While this approach is already applied in maxillofacial surgery, its implementation in dentistry is still restricted. However, recent advancements in artificial intelligence make it possible to automate several parts of the laborious modelling task, bringing such user-assisted decision-support tools closer to both clinicians and researchers. Therefore, the present narrative review aimed to present and discuss the current literature investigating patient-specific modelling in dentistry, its state-of-the-art applications, and research perspectives.

Dentistry increasingly integrates artificial intelligence (AI) to help improve the current state of clinical dental practice. However, this revolutionary technological field raises various complex ethical challenges. The objective of this systematic scoping review is to document the current uses of AI in dentistry and the ethical concerns or challenges they imply. Three health care databases (MEDLINE [PubMed], SciVerse Scopus, and Cochrane Library) and 2 computer science databases (ArXiv, IEEE Xplore) were searched. After identifying 1,553 records, the documents were filtered, and a full-text screening was performed. In total, 178 studies were retained and analyzed by 8 researchers specialized in dentistry, AI, and ethics. The team used Covidence for data extraction and Dedoose for the identification of ethics-related information. PRISMA guidelines were followed. Among the included studies, 130 (73.0%) studies were published after 2016, and 93 (52.2%) were published in journals specialized in computer sciences. The technologies used were neural learning techniques for 75 (42.1%), traditional learning techniques for 76 (42.7%), or a combination of several technologies for 20 (11.2%). Overall, 7 countries contributed to 109 (61.2%) studies. A total of 53 different applications of AI in dentistry were identified, involving most dental specialties. The use of initial data sets for internal validation was reported in 152 (85.4%) studies. Forty-five ethical issues (related to the use AI in dentistry) were reported in 22 (12.4%) studies around 6 principles: prudence (10 times), equity (8), privacy (8), responsibility (6), democratic participation (4), and solidarity (4). The ratio of studies mentioning AI-related ethical issues has remained similar in the past years, showing that there is no increasing interest in the field of dentistry on this topic. This study confirms the growing presence of AI in dentistry and highlights a current lack of information on the ethical challenges surrounding its use. In addition, the scarcity of studies sharing their code could prevent future replications. The authors formulate recommendations to contribute to a more responsible use of AI technologies in dentistry.

International audience; PurposeTo evaluate whether a concordance assessment (CA) software application is able to assess decision-making in restorative and prosthetic dentistry.Materials and methodsVignettes representing 10 different clinical situations were integrated into a software application. Each vignette included 3D digital models and a short case, as well as 5 therapeutic options rated on a 4-point Likert scale (-2 = strongly contraindicated; -1 = contraindicated; +1 = indicated; +2 = strongly indicated). A panel of 15 dental educators (9 educators from the prosthetic department [PD] and 6 from the conservative department [CD]) had to evaluate the indication of each of the 5 therapies for the 10 vignettes.ResultsThis pilot questionnaire showed good internal consistency on most therapies (Cronbach's α = 0.86), with the exception of more recently introduced therapies (overlay/veneerlay and endocrown). On a maximum score out of 100, the average of CD educators (79.2 ± 3.2) was not significantly different (P = .73) from that of a PD educator (77.8 ± 3.5). Scores ranged from 66.8 to 89.6. Analysis of the expert panel's responses also reported mostly (34/50) a distribution of responses that was characteristic of CA and uncertain situations.ConclusionThe present software application was able to reproduce and assess decision-making in dentistry with satisfying internal consistency of educators.

Three-dimensional files featuring patients’ geometry can be obtained through common tools in dental practice, such as an intraoral scanner (IOS) or Cone Beam Computed Tomography (CBCT). The use of 3D files in medical education is promoted, but only few methodologies were reported due to the lack of ease to use and accessible protocols for educators. The aim of this work was to present innovative and accessible methodologies to create 3D files in dental education. The first step requires the definition of the educational outcomes and the situations of interest. The second step relies on the use of IOS and CBCT to digitize the content. The last “post-treatment” steps involve free software for analysis of quality, re-meshing and simplifying the file in accordance with the desired educational activity. Several examples of educational activities using 3D files are illustrated in dental education and discussed. Three-dimensional files open up many accessible applications for a dental educator, but further investigations are required to develop collaborative tools and prevent educational inequalities between establishments.

The present article describes a digital workflow for the fabrication of definitive complete dentures in 2 appointments by reproducing the cameo surface and tooth arrangement of computer-aided design and computer-aided manufacturing (CAD-CAM) immediate dentures. This straightforward technique, which requires limited time and effort, can be easily applied by using an intraoral scanner, a dental CAD software program, and a milling machine.

Hydrogel-based regenerative endodontic procedures (REPs) are considered to be very promising therapeutic strategies to reconstruct the dental pulp (DP) tissue in devitalized human teeth. However, the success of the regeneration process is limited by residual bacteria that may persist in the endodontic space after the disinfection step and contaminate the biomaterial. The aim of this work was to develop an innovative fibrin hydrogel incorporating clindamycin (CLIN)-loaded Poly (d,l) Lactic Acid (PLA) nanoparticles (NPs) to provide the hydrogel with antibacterial properties. CLIN-PLA-NPs were synthesized by a surfactant-free nanoprecipitation method and their microphysical properties were assessed by dynamic light scattering, electrophoretic mobility and scanning electron microscopy. Their antimicrobial efficacy was evaluated on Enteroccocus faecalis by the determination of the minimal inhibitory concentration (MIC) and the minimal biofilm inhibition and eradication concentrations (MBIC and MBEC). Antibacterial properties of the nanocomposite hydrogel were verified by agar diffusion assays. NP distribution into the hydrogel and release from it were evaluated using fluorescent PLA-NPs. NP cytotoxicity was assessed on DP mesenchymal stem cells (DP-MSCs) incorporated into the hydrogel. Type I collagen synthesis was investigated after 7 days of culture by immunohistochemistry. We found that CLIN-PLA-NPs displayed a drug loading of 10 ± 2 μg per mg of PLA polymer and an entrapment efficiency of 43 ± 7%. Antibiotic loading did not affect NP size, polydispersity index and zeta potential. The MIC for Enterococcus faecalis was 32 μg mL-1. MBIC50 and MBEC50 were 4 and 16 μg mL-1, respectively. CLIN-PLA-NPs appeared homogenously distributed throughout the hydrogel. CLIN-PLA-NP-loaded hydrogels clearly inhibited E. faecalis growth. DP-MSC viability and type I collagen synthesis within the fibrin hydrogel were not affected by CLIN-PLA-NPs. In conclusion, CLIN-PLA-NP incorporation into the fibrin hydrogel gave the latter antibacterial and antibiofilm properties without affecting cell viability and function. This formulation could help establish an aseptic environment supporting DP reconstruction and, accordingly, might be a valuable tool for REPs.

Children affected by dentinogenesis imperfecta (DI) require restorative techniques or prosthodontic management to minimize the functional and psychosocial impacts of the condition. In cases of excessive wear of the deciduous dentition and moderate cooperation from the child, removable complete overdenture prostheses are the most suitable treatment option. However, limited restorative space is a technical challenge for the placement of such prostheses. Advances in digital technologies can help assist in the fabrication of monolithic prostheses with reduced thickness. The present clinical report describes the management of a moderately cooperative 7-year-old patient suffering from DI with severe tooth wear, reduced restorative space, and a high smile line. The design and fabrication of complete overdentures were performed using a digital workflow. This innovative monochromatic monolithic approach combined with the use of gingiva-shade composite resin respected the available restorative space while obtaining a natural esthetic appearance. Such a strategy requires regular denture replacement according to the child's growth and loss of deciduous dentition. An additional aim is to obtain the cooperation needed for a future global fixed rehabilitation over time.

Smile reconstruction is achieved using rigorous and detailed methodologies that are technically demanding and both time and cost intensive. These methodologies do not include the patient during the primary conception phase. New digital technologies using augmented reality (AR) offer the option of immediate diagnosis and pre-visualization of the potential outcome before the start of treatment. A 22-year-old patient with a congenitally missing maxillary right canine, peg-shaped maxillary lateral incisors, and multiple visible diastemas required an esthetic rehabilitation. An AR virtual mock-up using specialized software was used to preview and modify the restoration proposal in real time. Using the novel 'CAD-link' workflow, the final AR proposal could be imported into CAD software and transformed into a digital wax-up with the new virtual wax copy function. After a minimally invasive preparation, the final veneer reconstructions were precisely planned according to the previously developed design proposal and bonded according to the well-known adhesive protocol. The workflow described in this article links AR with CAD/CAM technology and is expected to be time and cost efficient. This patient-centered approach involves the patient from the very beginning and is therefore an excellent communication tool between the patient and the restorative team.

International audience; Finite element (FE) models are widely used to investigate the biomechanics of reconstructed premolars. However, parameter identification is a complex step because experimental validation cannot always be conducted. The aim of this study was to collect the experimentally validated FE models of premolars, extract their parameters, and discuss trends. A systematic review was performed following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Records were identified in three electronic databases (MEDLINE [PubMed], Scopus, The Cochrane Library) by two independent reviewers. Twenty-seven parameters dealing with failure criteria, model construction, material laws, boundary conditions, and model validation were extracted from the included articles. From 1306 records, 214 were selected for eligibility and entirely read. Among them, 19 studies were included. A heterogeneity was observed for several parameters associated with failure criteria and model construction. Elasticity, linearity, and isotropy were more often chosen for dental and periodontal tissues with a Young's modulus mostly set at 18-18.6 GPa for dentine. Loading was mainly simulated by an axial force, and FE models were mostly validated by in vitro tests evaluating tooth strains, but different conditions about experiment type, sample size, and tooth status (intact or restored) were reported. In conclusion, material laws identified herein could be applied to future premolar FE models. However, further investigations such as sensitivity analysis are required for several parameters to clarify their indication.

Mesenchymal stem cells (MSCs) represent alternative candidates to chondrocytes for cartilage engineering. However, it remains difficult to identify the ideal source of MSCs for cartilage repair since conditions supporting chondrogenic induction are diverse among published works. In this study, we characterized and evaluated the chondrogenic potential of MSCs from bone marrow (BM), Wharton’s jelly (WJ), dental pulp (DP), and adipose tissue (AT) isolated and cultivated under serum-free conditions. BM-, WJ-, DP-, and AT-MSCs did not differ in terms of viability, clonogenicity, and proliferation. By an extensive polychromatic flow cytometry analysis, we found notable differences in markers of the osteochondrogenic lineage between the 4 MSC sources. We then evaluated their chondrogenic potential in a micromass culture model, and only BM-MSCs showed chondrogenic conversion. This chondrogenic differentiation was specifically ascertained by the production of procollagen IIB, the only type II collagen isoform synthesized by well-differentiated chondrocytes. As a pilot study toward cartilage engineering, we encapsulated BM-MSCs in hydrogel and developed an original method to evaluate their chondrogenic conversion by flow cytometry analysis, after release of the cells from the hydrogel. This allowed the simultaneous quantification of procollagen IIB and α10, a subunit of a type II collagen receptor crucial for proper cartilage development. This work represents the first comparison of detailed immunophenotypic analysis and chondrogenic differentiation potential of human BM-, WJ-, DP-, and AT-MSCs performed under the same serum-free conditions, from their isolation to their induction. Our study, achieved in conditions compliant with clinical applications, highlights that BM-MSCs are good candidates for cartilage engineering.

Objective Regenerating a functional dental pulp in the pulpectomized root canal has been recently proposed as a novel therapeutic strategy in dentistry. To reach this goal, designing an appropriate scaffold able to prevent the growth of residual endodontic bacteria, while supporting dental pulp tissue neoformation, is needed. Our aim was to create an innovative cellularized fibrin hydrogel supplemented with chitosan to confer this hydrogel antibacterial property. Methods Several fibrin–chitosan formulations were first screened by rheological analyses, and the most appropriate for clinical use was then studied in terms of microstructure (by scanning electron microscopy), antimicrobial effect (analysis of Enterococcus faecalis growth), dental pulp-mesenchymal stem/stromal cell (DP-MSC) viability and spreading after 7 days of culture (LiveDead® test), DP-MSC ultrastructure and extracellular matrix deposition (transmission electron microscopy), and DP-MSC proliferation and collagen production (RT-qPCR and immunohistochemistry). Results A formulation associating 10 mg/mL fibrinogen and 0.5% (w/w), 40% degree of acetylation, medium molar mass chitosan was found to be relevant in order to forming a fibrin–chitosan hydrogel at cytocompatible pH (# 7.2). Comparative analysis of fibrin-alone and fibrin–chitosan hydrogels revealed a potent antibacterial effect of the chitosan in the fibrin network, and similar DP-MSC viability, fibroblast-like morphology, proliferation rate and type I/III collagen production capacity. Significance These results indicate that incorporating chitosan within a fibrin hydrogel would be beneficial to promote human DP tissue neoformation thanks to chitosan antibacterial effect and the absence of significant detrimental effect of chitosan on dental pulp cell morphology, viability, proliferation and collagenous matrix production.

Dental pulp (DP) is a specialized, highly vascularized, and innervated connective tissue mainly composed of undifferentiated mesenchymal cells, fibroblasts, and highly differentiated dentin-forming odontoblasts. Undifferentiated mesenchymal cells include stem/stromal cell populations usually called dental pulp mesenchymal stem cells (DP-MSCs) which differ in their self-renewal properties, lineage commitment, and differentiation capabilities. Analysis of surface antigens has been largely used to precisely identify these DP-MSC populations. However, a major difficulty is that these antigens are actually not specific for MSCs. Most of the markers used are indeed shared by other cell populations such as progenitor cells, mature fibroblasts, and/or perivascular cells. Accordingly, the detection of only one of these markers in a cell population is clearly insufficient to determine its stemness. Recent data reported that multiparametric flow cytometry, by allowing for the detection of several molecules on the surface of one single cell, is a powerful tool to elucidate the phenotype of a cell population both in vivo and in vitro. So far, DP-MSC populations have been characterized mainly based on the isolated expression of molecules known to be expressed by stem cells, such as Stro-1 antigen, melanoma cell adhesion molecule MCAM/CD146, low-affinity nerve growth factor receptor p75NTR/CD271, and the mesenchymal stem cell antigen MSCA-1. Using multiparametric flow cytometry, we recently showed that human DP-MSCs are indeed phenotypically heterogeneous and form several populations.The present paper describes the multiparametric flow cytometry protocol we routinely use for characterizing DP-MSCs. The description includes the design of the antibody panel and explains the selection of the different parameters related to the data quality control.

Dental pulp (DP) is a specialized, highly vascularized, and innervated connective tissue mainly composed of undifferentiated mesenchymal cells, fibroblasts, and highly differentiated dentin-forming odontoblasts. Undifferentiated mesenchymal cells include stem/stromal cell populations usually called dental pulp mesenchymal stem cells (DP-MSCs) which differ in their self-renewal properties, lineage commitment, and differentiation capabilities. Analysis of surface antigens has been largely used to precisely identify these DP-MSC populations. However, a major difficulty is that these antigens are actually not specific for MSCs. Most of the markers used are indeed shared by other cell populations such as progenitor cells, mature fibroblasts, and/or perivascular cells. Accordingly, the detection of only one of these markers in a cell population is clearly insufficient to determine its stemness. Recent data reported that multiparametric flow cytometry, by allowing for the detection of several molecules on the surface of one single cell, is a powerful tool to elucidate the phenotype of a cell population both in vivo and in vitro. So far, DP-MSC populations have been characterized mainly based on the isolated expression of molecules known to be expressed by stem cells, such as Stro-1 antigen, melanoma cell adhesion molecule MCAM/CD146, low-affinity nerve growth factor receptor p75NTR/CD271, and the mesenchymal stem cell antigen MSCA-1. Using multiparametric flow cytometry, we recently showed that human DP-MSCs are indeed phenotypically heterogeneous and form several populations.The present paper describes the multiparametric flow cytometry protocol we routinely use for characterizing DP-MSCs. The description includes the design of the antibody panel and explains the selection of the different parameters related to the data quality control.

INTRODUCTION: Dental anomalies in Osteogenesis imperfecta (OI), such as tooth discoloration, pulp obliteration (calcified dental pulp space), and taurodontism (enlarged dental pulp space) vary between and within patients. To better understand the associations and variations in these anomalies, a cross-sectional study was designed to analyze the dental phenotype in OI patients at the individual tooth type. METHOD: A cohort of 171 individuals with OI type I, III and IV, aged 3–55 years, were recruited and evaluated for tooth discoloration, pulp obliteration, and taurodontism at the individual tooth level, using intraoral photographs and panoramic radiographs. RESULTS: Genetic variants were identified in 154 of the participants. Patients with Helical α1 and α2 glycine substitutions presented the highest prevalence of tooth discoloration, while those with α1 Haploinsufficiency had the lowest (

During dental prosthetic rehabilitation, communication and conception are achieved using rigorous methodologies such as smile design protocols. The aim of the present pilot study was to compare two innovative strategies that used augmented reality for communication in dentistry. These strategies enable the user to instantly try a virtual smile proposition by taking a set of pictures from different points of view or by using the iPad as an enhanced mirror. Sixth-year dental students (n=18, women = 13, men = 5, mean age = 23.8) were included in this pilot study and were asked to answer a 5-question questionnaire studying the user experience using a visual analog scale (VAS). Answers were converted into a numerical result ranging from 0 to 100 for statistical analysis. Participants were not able to report a difference between the two strategies in terms of handling of the device (p=0.45), quality of the reconstruction (p=0.73), and fluidity of the software (p=0.67). Even if the participants’ experience with the enhanced mirror was more often reported as immersive and more likely to be integrated in a daily dental office practice, no significant increase was reported (p=0.15 and p=0.07). Further investigations are required to evaluate time and cost savings in daily practice. Software accuracy is also a major point to investigate in order to go further in clinical applications.

Papillon-Lefevre syndrome (PLS) is a rare disorder that leads to symptoms including the early progressive loss of deciduous and permanent teeth. Prosthodontic management of children and adolescents affected by PLS sometimes requires an immediate complete denture. Tooth mobility presents a challenge to the dentist, especially during impression-making. This clinical report describes the management of a 14-year-old boy with PLS by using an intraoral scanner to prevent conventional impressions and a fully digital workflow for the design and fabrication of immediate complete dentures.

Introduction Human dental pulp cells (HDPCs) are generally isolated and cultured with xenogeneic products and in stress conditions that may alter their biological features. However, guidelines from the American Food and Drug Administration and the European Medicines Agency currently recommend the use of protocols compliant with medicinal manufacturing. Our aim was to design an ex vivo procedure to produce large amounts of HDPCs for dentin/pulp and bone engineering according to these international recommendations. Methods HDPC isolation was performed from pulp explant cultures. After appropriate serum-free medium selection, cultured HDPCs were immunophenotyped with flow cytometry. Samples were then cryopreserved for 510 days. The post-thaw cell doubling time was determined up to passage 4 (P4). Karyotyping was performed by G-band analysis. Osteo/odontoblastic differentiation capability was determined after culture in a differentiation medium by gene expression analysis of osteo/odontoblast markers and mineralization quantification. Results Immunophenotyping of cultured HDPCs revealed a mesenchymal profile of the cells, some of which also expressed the stem/progenitor cell markers CD271, Stro-1, CD146, or MSCA-1. The post-thaw cell doubling times were stable and similar to fresh HDPCs. Cells displayed no karyotype abnormality. Alkaline phosphatase, osteocalcin, and dentin sialophosphoprotein gene expression and culture mineralization were increased in post-thaw HDPC cultures performed in differentiation medium compared with cultures in control medium. Conclusions We successfully isolated, cryopreserved, and amplified human dental pulp cells with a medicinal manufacturing approach. These findings may constitute a basis on which to investigate how HDPC production can be optimized for human pulp/dentin and bone tissue engineering.

International audience; Tooth vitality and health are related to the presence of a living connective tissue, the dental pulp (DP), in the center of the dental organ. The DP contains the tooth immune defence system that is activated against invading oral cariogenic bacteria during the caries process and the tissue repair/regeneration machinery involved following microorganisms' eradication. However, penetration of oral bacteria into the DP often leads to complete tissue destruction and colonization of the endodontic space by microorganisms. Classical endodontic therapies consist of disinfecting then sealing the endodontic space with a gutta percha-based material. However, re-infections of the endodontic space by oral bacteria can occur, owing to the lack of tightness of the material. Recent findings suggest that regenerating a fully functional pulp tissue may be an ideal therapeutic solution to maintain a tooth defence system that will detect and help manage future injuries. The objective of this paper was to explain the different revascularization and regeneration strategies that have been proposed to reconstitute a living DP tissue and to discuss the main challenges that have to be resolved to improve these therapeutic strategies.

Transplantation of mesenchymal stem/stromal cells (MSCs) has emerged as an effective method to treat diseased or damaged organs and tissues, and hundreds of clinical trials using MSCs are currently under way to demonstrate the validity of such a therapeutic approach. However, most MSCs used for clinical trials are prepared in research laboratories with insufficient manufacturing quality control.In particular, laboratories lack standardized procedures for in vitro isolation of MSCs from tissue samples, resulting in heterogeneous populations of cells and variable experimental and clinical results. MSCs are now referred to as Human Cellular Tissue-based Products or Advanced Therapy Medicinal Products, and guidelines from the American Code of Federal Regulation of the Food and Drug Administration (21 CFR Part 1271) and from the European Medicines Agency (European Directive 1394/2007) define requirements for appropriate production of these cells. These guidelines, commonly called “Good Manufacturing Practices” (GMP), include recommendations about laboratory cell culture procedures to ensure optimal reproducibility, efficacy and safety of the final medicinal product. In particular, the Food and Drug Administration divides ex vivo cultured cells into “minimally” and “more than minimally” manipulated samples, in function of the use or not of procedures “that might alter the biological features of the cells”. Today, minimal manipulation conditions have not been defined for the collection and isolation of MSCs (Torre et al. 2015)(Ducret et al. 2015).Most if not all culture protocols that have been reported so far are unsatisfactory, because of the use of xeno- or allogeneic cell culture media, enzymatic treatment and long-term cell amplification that are known to alter the quality of MSCs. The aim of this study was to describe a standardized procedure for recovering MSCs with minimal handling from two promising sources, the dental pulp (DP) and the Wharton’s jelly (WJ) of the umbilical cord. The quality and homogeneity of the expanded cell populations were assessed by using flow cytometry with criteria that go beyond the International Society of Cellular Therapy (ISCT) guidelines for MSC characterization.

The penetration of cariogenic oral bacteria into enamel and dentin during the caries process triggers an immune/inflammatory response in the underlying pulp tissue, the reduction of which is considered a prerequisite to dentinogenesis-based pulp regeneration. If the role of odontoblasts in dentin formation is well known, their involvement in the antibacterial response of the dental pulp to cariogenic microorganisms has yet to be elucidated. Our aim here was to determine if odontoblasts produce nitric oxide (NO) with antibacterial activity upon activation of Toll-like receptor-2 (TLR2), a cell membrane receptor involved in the recognition of cariogenic Gram-positive bacteria. Human odontoblast-like cells differentiated from dental pulp explants were stimulated with the TLR2 synthetic agonist Pam2CSK4. We found that NOS1, NOS2, and NOS3 gene expression was increased in Pam2CSK4-stimulated odontoblast-like cells compared to unstimulated ones. NOS2 was the most up-regulated gene. NOS1 and NOS3 proteins were not detected in Pam2CSK4-stimulated or control cultures. NOS2 protein synthesis, NOS activity and NO extracellular release were all augmented in stimulated samples. Pam2CSK4-stimulated cell supernatants reduced Streptococcus mutans growth, an effect counteracted by the NOS inhibitor L-NAME. In vivo, the NOS2 gene was up-regulated in the inflamed pulp of carious teeth compared with healthy ones. NOS2 protein was immunolocalized in odontoblasts situated beneath the caries lesion but not in pulp cells from healthy teeth. These results suggest that odontoblasts may participate to the antimicrobial pulp response to dentin-invading Gram-positive bacteria through NOS2-mediated NO production. They might in this manner pave the way for accurate dental pulp healing and regeneration.