Oral emergencies at Strasbourg teaching hospitals during the COVID-19 lockdown: Patient care circuits, typologies, and profiles / Urgences bucco-dentaires aux hôpitaux universitaires de Strasbourg et confinement lié au COVID-19 : parcours, typologie et profils

Purpose of research: We aimed to describe the type of emergencies as well as the population treated for oral emergencies at the Pôle de Médecine et Chirurgie Bucco-Dentaires (Dental Medicine and Surgery Center) of Strasbourg during the COVID-19 lockdown period from March 17 to May 9, 2020.Information on patient care circuits as well as the demographic and clinical data concerning all those who accessed the Center during the study period were collected by questionnaire and from medical files. Pain was rated on a numerical scale from 0 to 10. Diagnoses and treatments provided were divided into clinically relevant classes. During the forty-two days of activity, 2,470 patients were seen and 94.2 percent of them were treated. A constant increase in activity, almost doubling between the beginning and the end of the period, was observed. Pain with an intensity greater than or equal to 5 on the scale was reported by 77.9 percent of patients; pain greater than or equal to 7 by 52.5 percent of patients. Coordination between the various general practice and hospital organizations is necessary to deal with oral emergencies, considering the high number of patients concerned and the associated pain level. This coordination was particularly effective during the COVID-19 lockdown, which led to a massive and constantly increasing recourse to emergency dental care. We were able to describe and detail the consultations for oral emergencies and confirm that the intense associated pain did not allow treatment to be postponed.

But de l'étude: Décrire le type d'urgences ainsi que la population prise en charge pour des urgences bucco-dentaires au Pôle de Médecine et Chirurgie Bucco-Dentaires de Strasbourg au cours de la période de confinement liée au COVID-19 du 17 mars 2020 au 9 mai 2020.Le parcours des patients et les données démographiques et cliniques de l'ensemble des patients s'étant présentés pendant la période étudiée ont été collectées par questionnaire et dans les dossiers médicaux. La douleur a été évaluée sur une échelle numérique. Les diagnostics et les prises en charge ont été divisés en classes cliniquement pertinentes. Pendant les 42 jours d'activité, 2 470 patients se sont présentés et 94.2 % d'entre eux ont été pris en charge. On observe une augmentation constante avec un quasi doublement de l'activité entre le début et la fin de la période. Une douleur d'intensité supérieure ou égale à 5 a été rapportée par 77.9 % des patients ; une douleur supérieure ou égale à 7 par 52.5 % des patients. La coordination entre les différents acteurs de ville et hospitalier est une nécessité pour prendre en charge les urgences bucco-dentaires au vu du nombre de patients concernés et des douleurs associées. Cette coordination a été particulièrement efficace pendant la période de confinement qui a entrainé un recours massif aux soins d'urgence, recours ayant augmenté constamment. Les consultations pour urgences bucco-dentaires ont été détaillées et nous avons confirmé que les intenses douleurs associées ne permettent pas de reporter leur prise en charge.

Accuracy of Age Estimation Using Three Dental Age Estimation Methods in a Young, Large, and Multiethnic Patient Sample.

European countries have become host countries for migrants and unaccompanied minors. However, many migrants arrive without identity documents. Many methods exist to estimate age; among them, several methods using dental age have been proposed. Our objective was to evaluate the accuracy of biological age determination in a multiethnic sample using dental age estimated using three methods: Nolla, Demirjian, and the London Atlas. Orthopantomograms collected for 324 patients of various ethnicities aged from 4 to 20 years old were included. Then, for each orthopantomogram, a blind trained examiner used the three methods of age estimation. For each method, the estimated mean age was greater than the real mean age (p < 0.0001). The accuracy after 18 years old with a 1-year margin was under 50%. Demirjian's method gave a less accurate estimated age than Nolla's method (p < 0.0001) or the London Atlas (p < 0.001). The most accurate methods were those of Nolla and the London Atlas, with average absolute deviations of 1.3 and 1.2 years, respectively. Demirjian's method was much less accurate, with a deviation of around 2 years. The evaluated methods are unable to provide reliable information to determine if an individual is a minor.

The "new normal" of hygiene measures at the end of the COVID-19 epidemic: a survey among French dentists.

OBJECTIVES: The COVID-19 epidemic upset the standards in terms of hygiene and protection in the dental office, bringing additional precautions for dentists. The objective of our study was to draw the "new normal" of hygiene measures at the end of the COVID-19 epidemic. MATERIALS AND METHODS: A self-administered questionnaire about transitional recommendations for oral care in the context of the COVID-19 epidemic was published online in private groups dedicated to French dentists. RESULTS: The 246 respondents understood the reasons behind those recommendations, since 10 out of 11 measures reached a mean score greater than 2.5 on a 0 (not at all) to 4 (absolutely) scale when it came to determining whether the measure made the practitioner feel safe and ensured patient safety. Besides, more of the respondents intended to maintain the measures than they were to apply them before the epidemic. CONCLUSIONS: The COVID-19 epidemic reshaped the relationship to hygiene and protection measures in the context of dental practices. The "new normal" of hygiene measures at the end of the COVID-19 epidemic will probably involve more protective measures than before. CLINICAL RELEVANCE: These results constitute interesting avenues for public health deliberation, which would make it possible to best adapt future health recommendations in order to define the "new normal" of hygiene measures in dental practices at the end of the COVID-19 epidemic. Therefore, it could have an impact on all practitioners in their clinical activities.

Back pain prevention program: An evaluation after a 10-year implementation amongst dental students.

BACKGROUND: Many studies show a higher prevalence of back pain for dentists and dental students than in the general population. This leads to a need to integrate an effective back pain prevention program (BPPP) into the student's curriculum. We have implemented such a program for 10 years, and the objective was to evaluate its effectiveness. MATERIAL AND METHODS: Data from 102 dentists and students who benefited from the BPPP were collected. Back pain prevalence and its intensity (0-10 scale) regarding neck, upper back and lower back location were studied, as well as sex, age, implementation or not of elements of the BPPP into daily practice, and if so at what moment of the professional life. For identical items, answers were compared with those from a national survey conducted amongst French students and practitioners in 2018. RESULTS: Amongst the BPPP beneficiaries, 60% were suffering from chronic back pain versus 77% in the previous national survey (p < .001). Mean pain intensity was lower in each location for the BPPP beneficiaries on the 0-10 scale: neck 1.91 vs. 2.40 (p = .05); upper back 1.94 vs. 2.72 (p < .001); lower back 2.26 vs. 2.67 (p = .15). Respondents who implemented elements of the BPPP from the start of their clinical practice showed a prevalence of chronic back pain of 48.4%, against 77% for respondents who did so only from the first year or after (p < .05). CONCLUSION: Our BPPP seems to show a positive preventive effect on dentists and students after a 10-year implementation. It is a solid basis that can however be further improved.

Orofacial problems in scuba diving: prevalence and prevention-a large-scale survey among civilian divers in France.

Self-contained underwater breathing apparatus (SCUBA) diving is becoming widely democratized among hobbyist practitioners. It can cause orofacial problems, mostly linked to pressure changes. The aim of this study was to assess the prevalence of these problems and to analyze civilian divers' behavior about their dental prevention in France, via a cross-sectional study. Data from 1015 French civilian divers were collected via a nationwide online questionnaire in which participants indicated information concerning orofacial experienced problems during their diving activity, and their medical preventive habits. As results, oral manifestations were experienced by 25.2% of the divers, including barodontalgia (10.8%), mouth syndrome (13.4%), gum pain (2.8%) and dental fractures caused by barotrauma (3.7%) or shocks (1.9%). Mouth syndrome was more frequent among women (18.6%) and divers aged between 18 and 34 years (18.9%). The prevalence of dental fractures increased significantly with age. High diving level was associated with more frequent barodontalgia (17.5%), gum pain (7%) and barotrauma (7.6%). Among respondents, 43.5% completed a dental examination before a diving season and showed fewer oral problems during their scuba diving practice than those who did not. In conclusion, oral problems in scuba diving represent frequent events that can compromise the safety of divers. Despite awareness rising, there is a lack of recourse to the dentist. This leads to incomplete information, especially concerning the preventive means available to divers.

Periodontal Care and Treatment Provision by General Dentists in France.

AIM: In many countries, periodontal surgery is mainly provided by periodontists. This specialty is not recognised in France, where periodontal care and treatment are principally the responsibility of general dentists (GDs). The objective of this study was to investigate the periodontal care provided and factors associated with the treatment of periodontal diseases, including periodontal surgery, by GDs in France. METHODS: A national cross-sectional survey of GDs practicing in the French metropolitan area was conducted in 2019. A self-administered questionnaire was sent by mail to the GDs selected by stratified simple random sampling. It included questions on respondents' sociodemographic characteristics and their periodontal practice. A multivariate logistic regression model was employed to identify the factors associated with the practice of periodontal surgery by GDs. RESULTS: Three hundred eighty-five GDs responded (response rate, 23.4%). Their mean age was 45.2 years; 51.2% were male and 83.6% were in private practice. They reported performing selective periodontal examinations such as pocket probing on average for 34.2% of their patients, but only 5.5% of them performed them systematically. Several variables were significantly associated with the provision of periodontal surgical procedures such as the gender of the GDs, full mouth periodontal probing, implantology practice, insufficient fees, or uncertainty about treatment procedure. This survey confirmed the referral of patients for periodontal surgery by a minority of practitioners. It also highlighted insufficient screening and diagnostic procedures for periodontal diseases by GDs. CONCLUSIONS: There is a need to improve French GDs' periodontal skills and knowledge and to address other barriers that currently limit their ability to deliver comprehensive periodontal care.

Development of an innovative educational escape game to promote teamwork in dentistry.

BACKGROUND: Escape games have proven to be an innovative pedagogical tool that allows students to use the professional skills they acquired. The appeal of the game lies in the stimulation of the players' minds and in the diversity of the puzzles. PURPOSE/OBJECTIVES: To evaluate the effectiveness of an educational tool aimed at cultivating team spirit and group cohesion in dentistry students through a fun collaborative activity that mobilises their knowledge and skills. MATERIALS AND METHOD: Twenty-four students participated to the escape game over a one-day period. In order to win, they had to solve dentistry-related puzzles. RESULTS: Feedback was strongly positive. The balance between manipulations and theoretical questions stimulated them. Students did favour this type of activity which allows to increase interactions between students as well as with the teaching team. CONCLUSION: Escape games in dental schools foster a supportive learning environment and stimulated students' motivation and group cohesion.

Comparative effectiveness of nonsurgical interventions in the treatment of patients with knee osteoarthritis: A PRISMA-compliant systematic review and network meta-analysis.

BACKGROUND: To find out, based on the available recent randomized controlled trials (RCTs), if the nonsurgical interventions commonly used for knee osteoarthritis patients are valid and quantify their efficiency. METHODS: The database of MEDLINE and EMBASE were searched for RCTs evaluating nonsurgical treatment strategies on patients with mild to moderate knee osteoarthritis. A Bayesian random-effects network meta-analysis was performed. The primary outcome was the mean change from baseline in the Western Ontario and McMaster university (WOMAC) total score at 12 months. Raw mean differences with 95% credibility intervals were calculated. Treatments were ranked by probabilities of each treatment to be the best. RESULTS: Thirteen trials assessed 7 strategies with WOMAC at 12 months: injection of platelet rich plasma (PRP), corticosteroids, mesenchymal stem cells (MSCs), hyaluronic acid, ozone, administration of nonsteroidal anti-inflammatory drugs with or without the association of physiotherapy. For treatment-specific effect size, a greater association with WOMAC decrease was found significantly for MSCs (mean difference, -28.0 [95% CrI, -32.9 to -22.4]) and PRP (mean difference, -19.9 [95% CrI, -24.1 to -15.8]). Rank probabilities among the treatments indicated that MSCs had a much higher probability (P = .91) of being the best treatment compared with other treatments, while PRP ranked as the second-best treatment (P = .89). CONCLUSION: In this systematic review and network meta-analysis, the outcomes of treatments using MSCs and PRP for the management of knee osteoarthritis were associated with long-term improvements in pain and function. More high quality RCTs would be needed to confirm the efficiency of MSCs and PRP for the treatment of patients with knee osteoarthritis.

Mechanistic Illustration: How Newly-Formed Blood Vessels Stopped by the Mineral Blocks of Bone Substitutes Can Be Avoided by Using Innovative Combined Therapeutics.

One major limitation for the vascularization of bone substitutes used for filling is the presence of mineral blocks. The newly-formed blood vessels are stopped or have to circumvent the mineral blocks, resulting in inefficient delivery of oxygen and nutrients to the implant. This leads to necrosis within the implant and to poor engraftment of the bone substitute. The aim of the present study is to provide a bone substitute currently used in the clinic with suitably guided vascularization properties. This therapeutic hybrid bone filling, containing a mineral and a polymeric component, is fortified with pro-angiogenic smart nano-therapeutics that allow the release of angiogenic molecules. Our data showed that the improved vasculature within the implant promoted new bone formation and that the newly-formed bone swapped the mineral blocks of the bone substitutes much more efficiently than in non-functionalized bone substitutes. Therefore, we demonstrated that our therapeutic bone substitute is an advanced therapeutical medicinal product, with great potential to recuperate and guide vascularization that is stopped by mineral blocks, and can improve the regeneration of critical-sized bone defects. We have also elucidated the mechanism to understand how the newly-formed vessels can no longer encounter mineral blocks and pursue their course of vasculature, giving our advanced therapeutical bone filling great potential to be used in many applications, by combining filling and nano-regenerative medicine that currently fall short because of problems related to the lack of oxygen and nutrients.

Cleaning of dental handpieces and associated parameters: Internal and external cleaning, drying and rotation.

PURPOSE: To evaluate the cleaning of dental handpieces and its associated parameters, internal, external cleaning and drying, and rotation, for two washer-disinfectors: Teon+ by W&H, and a dental rack for WD290 by Belimed. METHODS: An original method was developed with resin flags on dental burs to assess the inner rotation during the cleaning cycle. Concerning the cleaning and drying evaluation, three groups (9, 24 and 22 handpieces) were used in different conditions: soiled with Soil Test, soiled with heparinized blood, used in real conditions after a dental procedure, and clean (as control). Cycles were performed with the two washer-disinfectors, followed by a visual evaluation and a biuret reaction test. RESULTS: The method we developed was effective to assess the inner rotation of handpieces. The internal cleaning was successful for real conditions and control handpieces, but unsuccessful for all the artificially soiled handpieces except one. All the handpieces showed substantial humidity on their inner surfaces after cleaning. The internal cleaning of handpieces and its evaluation are both difficult to perform. A questioning about the relevance of some tests required in the ISO 15883 about handpieces requires further study. Cleaning devices and their parameters should be optimized to offer better cleaning skills, and testing-tools should be developed and validated to easily assess their performances. CLINICAL SIGNIFICANCE: Easy-to-use testing tools should be developed and validated, and dental handpiece cleaning tests should be redefined to fit with the reality of practices. According to the actual performance of cleaning, and even though sterilization will largely contribute to the reduction of the infectious risk of internal handpiece structures, it is unclear whether cleaning procedures can ensure totally safe practices.

An Evaluation of Two Systems for the Management of the Microbiological Quality of Water in Dental Unit Waterlines: Hygowater® and IGN Calbénium®.

Water in dental unit waterlines (DUWL) represents a risk for vulnerable patients if its microbiological quality is not controlled. The aim of this prospective study was to evaluate two systems for its management under real conditions: Hygowater® and IGN Calbenium®. Samples of the output water of DUWL were obtained for 5 previously contaminated units connected to Hygowater®, and 5 non-contaminated units connected to IGN Calbenium®, which was already effective for more than 1 year, as a control group. Samples were regularly collected up to 6 months after the implementation of Hygowater®, and were then cultured and analyzed. With IGN Calbenium®, except for a technical problem and a sample result in one unit at 6 months (Heterotrophic Plate Count (HPC) at 37 °C of 66 colony forming units (cfu)/mL), the results showed an absence of contamination. Hygowater® took a couple of weeks to be effective on initially contaminated DUWL (over 200 cfu/mL for all the units), then showed its efficacy for 2 months (HPC at 37 °C with a mean of 40.2 ufc/mL, and HPC at 22 °C with a mean of 0.2 ufc/mL). At 6 months, results were satisfactory for HPC at 22 °C (mean of 12 ufc/mL), but HPC at 37 °C gave non-satisfactory results for 4 of the 5 units (mean of 92.2 ufc/mL). Both systems have an effect on the microbiological quality of DUWL. IGN Calbenium® appears to be more reliable on a long-term basis.

Changes in tooth brushing frequency and its associated factors from 2006 to 2014 among French adolescents: Results from three repeated cross sectional HBSC studies.

OBJECTIVES: This study aimed to evaluate in the changes in the percentage of adolescents who brush their teeth twice a day and the association with socio-economic status and health behaviors between 2006, 2010 and 2014 among adolescents from the French cross-sectional studies of the Health Behavior in School-aged Children (HBSC) survey. METHODS: Our sample included 18727 adolescents aged 11, 13 or 15 years old (y/o). The relationship between toothbrushing frequency (TBF) and eating habits, health and socio-economic status markers, family status, school perception, substance use, sedentary lifestyle and physical activity, together with their evolution over the 3 studies, were investigated using multivariate logistic regression. RESULTS: The proportion of adolescents brushing twice a day increased from 68.8% in 2006 to 70.8% in 2010 and 78.8% in 2014 (p<0.0001). Notable associated factors (p<0.0001) were: being a girl (adjusted Odds Ratio = 1.5) and, even more, an older girl (aOR 1.5 for 15 y/o vs 11 y/o girls), having breakfast (aOR 1.4) and eating fruits daily (aOR 1.6), excellent perceived health (aOR 1.2), obesity or overweight (aOR 0.6), being bullied at school (aOR 0.8), and perceived family wealth (aOR 1.4 for High vs Low). No impact from any associated factor changed over the 3 studies. CONCLUSIONS: Among French adolescents, TBF improved from 2006 to 2014. TBF was significantly associated with other health behaviors. These associations stayed similar in 2006, 2010 and 2010. This increase in TBF may be linked with global prevention programs developed during this time period. These programs should be maintained and associated with more specific ones targeting and adapted to disadvantaged populations, in order to reduce inequalities in oral hygiene and oral health.

[Oral care and the Coronavirus COVID-19 epidemic]. / Soins bucco-dentaires et épidémie de Coronavirus COVID-19.

The COVID-19 Coronavirus epidemic started in December 2019 in China, and progressed very quickly in France. Its consequences were the implementation of national measures such as the containment of the population, but also a disorganization of the healthcare system, in particular concerning oral care. Indeed, dental procedures produce aerosols which can be loaded with viral particles, and as such, constitute a major contamination route by the virus. At the request of the Conference of Deans of the Faculties of Odontology, the National College of University Dentists in Public Health (CNCDUSP) set up a working group in order to issue recommendations for oral care in the context of the COVID-19 epidemic, given the specific risks faced by practitioners. Considering the lack of awareness of the specifics of dentistry in the medical world and among decision-makers, and given the speed with which national measures to fight the epidemic were implemented, the recommendations of the CNCDUSP had to be drawn up rigorously and quickly before being released to the profession. They take into account epidemiological data related to the virus, the specificities of oral care, and thus propose protective measures for dental surgery professionals.The necessary adaptation of the healthcare system during an epidemic will certainly make it possible to learn lessons from this health crisis.

[Oral care and the Coronavirus COVID-19 epidemic] / Soins bucco-dentaires et épidémie de Coronavirus COVID-19.

The COVID-19 Coronavirus epidemic started in December 2019 in China, and progressed very quickly in France. Its consequences were the implementation of national measures such as the containment of the population, but also a disorganization of the healthcare system, in particular concerning oral care. Indeed, dental procedures produce aerosols which can be loaded with viral particles, and as such, constitute a major contamination route by the virus. At the request of the Conference of Deans of the Faculties of Odontology, the National College of University Dentists in Public Health (CNCDUSP) set up a working group in order to issue recommendations for oral care in the context of the COVID-19 epidemic, given the specific risks faced by practitioners. Considering the lack of awareness of the specifics of dentistry in the medical world and among decision-makers, and given the speed with which national measures to fight the epidemic were implemented, the recommendations of the CNCDUSP had to be drawn up rigorously and quickly before being released to the profession. They take into account epidemiological data related to the virus, the specificities of oral care, and thus propose protective measures for dental surgery professionals.The necessary adaptation of the healthcare system during an epidemic will certainly make it possible to learn lessons from this health crisis.

Prevalence of sensitive teeth and associated factors: a multicentre, cross-sectional questionnaire survey in France.

BACKGROUND: As far as we know, little data, whether obtained from self-administered questionnaires or upon dental clinical examination, has been published on the prevalence of sensitive teeth (ST) in the French adult population. The objectives of the present work were to estimate ST prevalence and characteristics in the general population of France and to explore the associated factors. METHOD: A multicentre cross-sectional study was conducted between November 2011 and March 2013 in six French cities. Adult passers-by in public places were invited to answer an electronic questionnaire on a tablet computer. Only people who declared having at least one natural tooth were included in the study. A logistic regression model was used for the multivariate analysis. RESULTS: The prevalence of ST during the previous 12 months reported by the sample of 2413 participants was 42.2% [95% CI: 40.2-44.1%]. The final logistic regression model showed significant statistical associations between ST and female gender, use of tobacco, consumption of soft drinks, limited access to oral care and poor oral hygiene habits (p < 0.05). CONCLUSIONS: This study provides prevalence data on ST in a general population in France, which seems to remain high despite the existence of many therapies. It should alert professionals to a clinical manifestation that is becoming increasingly prevalent and that they will have to take into consideration to help reduce the discomfort arising from it.

Mobile Dental Delivery System: An Effective Protocol for Hygiene and Disinfection.

Mobile dental delivery systems (MDDSs) are receiving growing interest for reaching isolated patients, as well as in dental care for fragile and hospitalized patients, with the advantage of being able to be used from room to room or during general anesthesia (GA) in an operating room. Therefore, ensuring the care safety is crucial. The aim of this study was to elaborate and assess an MDDS maintenance protocol, containing the management of dental unit waterlines and adapted to specific conditions such as dental care under GA. A step-by-step protocol was established and implemented for an MDDS used during dental care under GA in children. Samples of the output water were collected at J0, J+1, 3, 6, 12, and 24 months, and cultured to observe the microbiological quality of the water. All the results (heterotrophic plate count at 22 °C, at 37 °C, and specific pathogenic germs sought) showed an absence of contamination. The protocol presented was effective over time and allowed ensuring the safety of care to be ensured when using MDDS, even during dental procedures under GA. As a result, it could be implemented by any dental care delivery structure wanting to reinforce the safety of its practice.

Soins bucco-dentaires et épidémie de Coronavirus COVID-19.

The COVID-19 Coronavirus epidemic started in December 2019 in China, and progressed very quickly in France. Its consequences were the implementation of national measures such as the containment of the population, but also a disorganization of the healthcare system, in particular concerning oral care. Indeed, dental procedures produce aerosols which can be loaded with viral particles, and as such, constitute a major contamination route by the virus. At the request of the Conference of Deans of the Faculties of Odontology, the National College of University Dentists in Public Health (CNCDUSP) set up a working group in order to issue recommendations for oral care in the context of the COVID-19 epidemic, given the specific risks faced by practitioners. Considering the lack of awareness of the specifics of dentistry in the medical world and among decision-makers, and given the speed with which national measures to fight the epidemic were implemented, the recommendations of the CNCDUSP had to be drawn up rigorously and quickly before being released to the profession. They take into account epidemiological data related to the virus, the specificities of oral care, and thus propose protective measures for dental surgery professionals.The necessary adaptation of the healthcare system during an epidemic will certainly make it possible to learn lessons from this health crisis.

Back pain prevalence, intensity and associated factors in French dentists: a national study among 1004 professionals.

OBJECTIVES: Back pains are the most frequent musculoskeletal disorders among dentists, exposed to many work-related risk factors. We aimed to assess the prevalence and intensity of back pains as well as the impact of some work behaviors among a large sample of dentists. MATERIALS AND METHODS: Data from 1004 French dentists were collected via an Internet questionnaire. Neck, upper back and lower back pains prevalence, intensity (0-10 scale) and consequences on work were studied, as well as sex, age, years of practice, working position, type of seat, stretching on work days. RESULTS: Dentists were 77.9% to report chronic back pains, with intensity from 3.9 to 4.3 according to location. Women reported more frequent and intense pains than men in neck and upper back (OR 1.5). Age and years of practice were associated with more intense pains (OR up to 3.9), dentists alternating standing and sitting positions reported more frequent and more intense pains in upper and lower back (OR up to 1.5) than those with a fixed position, be it sitting or standing. CONCLUSIONS: Prevalence and intensity of back pain are important among dentists and increase greatly over working life. Preventive methods such as ergonomics exist and awareness should be raised among dentists and dental student. These slides can be retrieved under Electronic Supplementary Material.

Application of Chitosan in Bone and Dental Engineering.

Chitosan is a deacetylated polysaccharide from chitin, the natural biopolymer primarily found in shells of marine crustaceans and fungi cell walls. Upon deacetylation, the protonation of free amino groups of the d-glucosamine residues of chitosan turns it into a polycation, which can easily interact with DNA, proteins, lipids, or negatively charged synthetic polymers. This positive-charged characteristic of chitosan not only increases its solubility, biodegradability, and biocompatibility, but also directly contributes to the muco-adhesion, hemostasis, and antimicrobial properties of chitosan. Combined with its low-cost and economic nature, chitosan has been extensively studied and widely used in biopharmaceutical and biomedical applications for several decades. In this review, we summarize the current chitosan-based applications for bone and dental engineering. Combining chitosan-based scaffolds with other nature or synthetic polymers and biomaterials induces their mechanical properties and bioactivities, as well as promoting osteogenesis. Incorporating the bioactive molecules into these biocomposite scaffolds accelerates new bone regeneration and enhances neovascularization in vivo.

Polymer-Based Instructive Scaffolds for Endodontic Regeneration.

The challenge of endodontic regeneration is modulated by clinical conditions which determine five kinds of tissue requirements: pulp connective-tissue formation, dentin formation, revascularization, reinnervation and radicular edification. Polymer scaffolds constitute keystone of the different endodontic regenerative strategies. Indeed, scaffolds are crucial for carrying active molecules and competent cells which optimize the regeneration. Hydrogels are very beneficial for controlling viscosity and porosity of endodontic scaffolds. The nanofibrous and microporous scaffolds mimicking extracellular matrix are also of great interest for promoting dentin-pulp formation. Two main types of polymer scaffolds are highlighted: collagen and fibrin. Collagen scaffolds which are similar to native pulp tissue, are adequate for pulp connective tissue formation. Functionnalization by active biomolecules as BMP, SDF-1, G-CSF enhances their properties. Fibrin or PRF scaffolds present the advantage of promoting stem cell differentiation and concomitant revascularisation. The choice of the type of polymers (polypeptide, PCL, chitosan) can depend on its ability to deliver the active biomolecule or to build as suitable hydrogel as possible. Since 2010s, proposals to associate different types of polymers in a same scaffold have emerged for adding advantages or for offsetting a disadvantage of a polymer. Further works would study the synergetic effects of different innovative polymers composition.