Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Prevention strategies by analysing socio-environmental predictors of oral health : epidemiology of hard maxillofacial tissues’ preservation and regeneration

La prévention, inculquée dès le plus jeune âge via l’hygiène bucco-dentaire (HBD), est efficace sur la majorité des pathologies orales. Il existe une population d’enfants à haut risque de pathologies orales, cumulant HBD insuffisante, alimentation inadaptée et vivant dans un environnement de faible niveau socio-économique. De 2006 à 2014, l’HBD des 11-15 ans s’est améliorée, mais une population à risque persiste. Cette amélioration s’observe également à l’échelle européenne de 2006 à 2018. La prévention peut montrer ses limites et les pathologies orales s’installer. Lorsqu’elles mènent à une destruction osseuse, la greffe ou l’utilisation de substituts osseux est souvent nécessaire. Nous avons passé en revue les différents substituts osseux, leurs propriétés et indications. Nous avons développé une combinaison d’un substitut osseux, de facteurs de croissances et de cellules souches permettant la revascularisation de défauts osseux de grande étendue. Une étude en population générale montre que ce type de matériau est accepté par plus de 90% de la population, s’affranchissant des barrières éthiques et craintes techniques liées à d’autres stratégies.Prevention, instilled during childhood via oral hygiene, is efficient against the majority of oral diseases. We identified a population of French children at high risk of oral diseases, cumulating insufficient oral hygiene, inadequate diet and living in low socio-economic status environment. From 2006 to 2014, oral hygiene improved among children of 11-15 years old, but a high-risk population still exists. This improvement was also observed in the whole Europe from 2006 to 2018. Prevention has its limits and oral diseases may lead to bone destruction. Grafts or bone substitutes are often needed. We reviewed the different bone substitutes, their characteristics and uses. We developed a combination of a bone substitute, growth factors and stem cells which allows the revascularization of large bone defects. We conducted a study among general population which showed that this kind of substitute is well accepted by over 90% of the population, avoiding ethic barriers and technical fears which are common for other treatments such as allogenic or xenogenic bone transplants

Parodontite et déclin cognitif (revue systématique de la littérature)

TOULOUSE3-BU Santé-Centrale (315552105) / SudocSudocFranceF

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

Abstract 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

Compliance of the Dryness of Dental Handpieces for Their Sterilization under Various Treatment Conditions

Objectives: In the protocol for cleaning and sterilizing dental handpieces (DHs), water retention within the instrument poses a challenge and may compromise the sterilization process. This study aimed to assess the reliability and reproducibility of the sterilization protocol regarding the dryness of DHs. It evaluated the presence of residual water in these instruments after various conditions of treatment through multiple dryness tests. Methods: This comparative study examined the dryness of seven different DHs following five washing–disinfection and/or sterilization protocols. Dabbing tests, shaking by hand, or compressed air tests through DHs and over absorbent paper were employed to ascertain the thorough dryness of DHs after treatment. As soon as the first sign of water appeared on the absorbent paper, the DH was deemed to be not dry. Results: Upon completion of the washing–disinfection protocol without sterilization, five out of seven DHs were deemed dry using the dabbing test, yet none were fully dry when subjected to shaking or compressed air. However, in the four protocols incorporating final sterilization, all DHs were dry according to the three drying tests. Conclusion: This study underscores the essential role of the sterilization step in eliminating residual water from DHs, thereby ensuring optimal conditions for effective sterilization in terms of dryness. Furthermore, the study recommends against relying solely on the dabbing drying test, emphasizing the importance of shaking or using compressed air to confirm instrument dryness

Adolescent tooth brushing frequency evolution (2006-2014), risk factors and causality hypothesis

International audienceObjectivesTo analyze the evolution of tooth brushing frequency (TBF) as well as the impact of socio-economic status and health behaviors between 2006, 2010 and 2014 among adolescents from the French Health Behavior in School-aged Children (HBSC) cross-sectional studies.MethodsWe included 18727 adolescents aged 11, 13 or 15 years old (y/o). The relationship between TBF and variables such as eating habits, health and socio-economic status markers as well as their evolution over the 3 studies were analyzed using logistic regression. We used directed acyclic graphs (DAGs) to represent the potential chain of causality between TBF, its associated factors, as well as latent variables such as the risk for oral diseases.ResultsProportion 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 predictors (p < 0.0001) were being a girl (adjusted Odd Ratio = 1.5) and even more an older girl (aOR 1.5 for 15y/o vs 11 y/o girls), having breakfast and fruits daily (aOR 1.4 and 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). Impacts of these predictors were stable over the 3 studies. DAGs highlighted the fact that a low TBF and its associated risk factors described a high-risk population for poor oral and global health. Variables at the origin of those risks seemed to be age, sex, familial environment, socio-economic environment and education.ConclusionsTBF among French adolescents improved from 2006 to 2014. This may be linked with global prevention programs developed during this time period. These programs should be associated with more specific ones targeted towards and adapted to disadvantaged populations to diminish inequalities. The use of DAGs is a powerful tool to identify the origin of those inequalities as well as the right factors to target in order to achieve efficient prevention

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

International audienceMobile 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

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

ObjectivesThis 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.MethodsOur 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.ResultsThe proportion of adolescents brushing twice a day increased from 68.8% in 2006 to 70.8% in 2010 and 78.8% in 2014 (pConclusionsAmong 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

Bone substitutes: a review of their characteristics, clinical use, and perspectives for large bone defects management

Bone replacement might have been practiced for centuries with various materials of natural origin, but had rarely met success until the late 19th century. Nowadays, many different bone substitutes can be used. They can be either derived from biological products such as demineralized bone matrix, platelet-rich plasma, hydroxyapatite, adjunction of growth factors (like bone morphogenetic protein) or synthetic such as calcium sulfate, tri-calcium phosphate ceramics, bioactive glasses, or polymer-based substitutes. All these substitutes are not suitable for every clinical use, and they have to be chosen selectively depending on their purpose. Thus, this review aims to highlight the principal characteristics of the most commonly used bone substitutes and to give some directions concerning their clinical use, as spine fusion, open-wedge tibial osteotomy, long bone fracture, oral and maxillofacial surgery, or periodontal treatments. However, the main limitations to bone substitutes use remain the management of large defects and the lack of vascularization in their central part, which is likely to appear following their utilization. In the field of bone tissue engineering, developing porous synthetic substitutes able to support a faster and a wider vascularization within their structure seems to be a promising way of research

Polymer-Based Instructive Scaffolds for Endodontic Regeneration

International audienceThe 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