Comparing intraosseous computerized anaesthesia with inferior alveolar nerve block in the treatment of symptomatic irreversible pulpitis: A randomized controlled trial.

AIM: The aim of this study was to compare the cardiovascular effects [heart rate, oxygen saturation (SpO2 ), systolic and diastolic blood pressure] and the anaesthetic efficacy of intraosseous computerized anaesthesia (ICA) versus inferior alveolar nerve block (IANB) in Symptomatic irreversible pulpitis (SIP). METHODOLOGY: The study protocol was registered with ClinicalTrials.gov (NCT03802305). In a randomized, prospective clinical trial, 72 mandibular molar teeth with SIP were randomly allocated to conventional IANB injection (n = 36) or ICA injection (n = 36), both with 1.8 mL of 4% articaine with 1:100 000 epinephrine. The primary objective was to assess the cardiovascular parameters (heart rate, oxygen saturation, blood pressure) before, during and after the anaesthesia. The secondary objectives were to compare ICA with IANB for success and postoperative outcomes for up to 3 days. RESULTS: The maximum increase in heart rate in the ICA group was greater than in the IANB. Other cardiovascular parameters did not show differences throughout the clinical procedure. There were no statistically significant differences (p > .05) between groups for sex, age, or anxiety. The total success rate of ICA (91.43%) was significantly higher (p = .0034) than that of IANB (69.44%). CONCLUSIONS: This study establishes that ICA is safe and efficient in the first intention for the treatment of SIP of the mandibular molar.

A critical analysis of research methods and experimental models to study biocompatibility of endodontic materials.

Materials used for endodontics and with direct contact to tissues have a wide range of indications, from vital pulpal treatments to root filling materials and those used in endodontic surgery. In principle, interaction with dental materials may result in damage to tissues locally or systemically. Thus, a great variety of test methods are applied to evaluate a materials' potential risk of adverse biological effects to ensure their biocompatibility before commercialization. However, the results of biocompatibility evaluations are dependent on not only the tested materials but also the test methods due to the diversity of these effects and numerous variables involved. In addition, diverse biological effects require equally diverse assessments on a structured and planned approach. Such a structured assessment of the materials consists of four phases: general toxicity, local tissue irritation, pre-clinical tests and clinical evaluations. Various types of screening assays are available; it is imperative to understand their advantages and limitations to recognize their appropriateness and for an accurate interpretation of their results. Recent scientific advances are rapidly introducing new materials to endodontics including nanomaterials, gene therapy and tissue engineering biomaterials. These new modalities open a new era to restore and regenerate dental tissues; however, all these new technologies can also present new hazards to patients. Before any clinical usage, new materials must be proven to be safe and not hazardous to health. Certain international standards exist for safety evaluation of dental materials (ISO 10993 series, ISO 7405 and ISO 14155-1), but researchers often fail to follow these standards due to lack of access to standards, limitation of the guidelines and complexity of new experimental methods, which may cause technical errors. Moreover, many laboratories have developed their testing strategy for biocompatibility, which makes any comparison between findings more difficult. The purpose of this review was to discuss the concept of biocompatibility, structured test programmes and international standards for testing the biocompatibility of endodontic material biocompatibility. The text will further detail current test methods for evaluating the biocompatibility of endodontic materials, and their advantages and limitations.

Comparative assessment of complete-coverage, fixed tooth-supported prostheses fabricated from digital scans or conventional impressions: A systematic review and meta-analysis.

STATEMENT OF PROBLEM: Intraoral scanners have significantly improved over the last decade. Nevertheless, data comparing intraoral digital scans with conventional impressions are sparse. PURPOSE: The purpose of this systematic review and meta-analysis was to determine the impact of impression technique (digital scans versus conventional impressions) on the clinical time, patient comfort, and marginal fit of tooth-supported prostheses. MATERIAL AND METHODS: The authors conducted a literature search based on the Population, Intervention, Comparison, and Outcome (PICO) framework in 3 databases to identify clinical trials with no language or date restrictions. The mean clinical time, patient comfort, and marginal fit values of each study were independently extracted by 2 review authors and categorized according to the scanning or impression method. The authors assessed the study-level risk of bias. RESULTS: A total of 16 clinical studies met the inclusion criteria. The mean clinical time was statistically similar for digital scan procedures (784 ±252 seconds) and for conventional impression methods (1125 ±159 seconds) (P>.05). The digital scan techniques were more comfortable for patients than conventional impressions; the mean visual analog scale score was 67.8 ±21.7 for digital scans and 39.6 ±9.3 for conventional impressions (P<.05). The mean marginal fit was 80.9 ±31.9 µm and 92.1 ±35.4 µm for digital scan and conventional impressions, respectively, with no statistically significant difference (P>.05). CONCLUSIONS: Digital scan techniques are comparable with conventional impressions in terms of clinical time and marginal fit but are more comfortable for patients than conventional impression techniques.

Specialized pro-resolving lipid mediators in endodontics: a narrative review.

Endodontics is the branch of dentistry concerned with the morphology, physiology, and pathology of the human dental pulp and periradicular tissues. Human dental pulp is a highly dynamic tissue equipped with a network of resident immunocompetent cells that play major roles in the defense against pathogens and during tissue injury. However, the efficiency of these mechanisms during dental pulp inflammation (pulpitis) varies due to anatomical and physiological restrictions. Uncontrolled, excessive, or unresolved inflammation can lead to pulp tissue necrosis and subsequent bone infections called apical periodontitis. In most cases, pulpitis treatment consists of total pulp removal. Although this strategy has a good success rate, this treatment has some drawbacks (lack of defense mechanisms, loss of healing capacities, incomplete formation of the root in young patients). In a sizeable number of clinical situations, the decision to perform pulp extirpation and endodontic treatment is justifiable by the lack of therapeutic tools that could otherwise limit the immune/inflammatory process. In the past few decades, many studies have demonstrated that the resolution of acute inflammation is necessary to avoid the development of chronic inflammation and to promote repair or regeneration. This active process is orchestrated by Specialized Pro-resolving lipid Mediators (SPMs), including lipoxins, resolvins, protectins and maresins. Interestingly, SPMs do not have direct anti-inflammatory effects by inhibiting or directly blocking this process but can actively reduce neutrophil infiltration into inflamed tissues, enhance efferocytosis and bacterial phagocytosis by monocytes and macrophages and simultaneously inhibit inflammatory cytokine production. Experimental clinical application of SPMs has shown promising result in a wide range of inflammatory diseases, such as renal fibrosis, cerebral ischemia, marginal periodontitis, and cancer; the potential of SPMs in endodontic therapy has recently been explored. In this review, our objective was to analyze the involvement and potential use of SPMs in endodontic therapies with an emphasis on SPM delivery systems to effectively administer SPMs into the dental pulp space.

Educational gaming for dental students: Design and assessment of a pilot endodontic-themed escape game.

INTRODUCTION: The concept of escape games dedicated to dental students is a new learning experience that has not yet been extensively explored. The aim of this pilot study was to assess the impact and perceived value of an endodontic-themed escape game as assessed by fourth-year dental students. METHODS: This study was conducted at the University of Nantes, Faculty of Dental Surgery using a cross-sectional pre- and post-test research design to assess students' changes in performance. Students in the fourth year of dental surgery study (n = 18) were divided in four groups for this study. The answers to the pre-test/post-test were 50 true/false questions. Moreover, a 20-question perception survey was given to all the participants after completion of the escape game. The study data were collected in May 2019. An unpaired t test analysed the mean differences between the groups. RESULTS: The results showed a statistically significant increase in post-test results (75.33% ± 10.17% of correct answers) compared to the pre-test results (67.33% ± 5.94% of correct answers) P < .05. Analysis of variance revealed that this change in score was not significantly different between the four groups. The students perceived the endodontic-themed escape game to be relevant. A one-sample t test indicated that students' mean (SD) perception 4.4 (0.7) was statistically significantly higher than the mean value of the evaluation scale P < .001. The students found this educational game to be a useful experience that helped them recall/apply knowledge whilst promoting teamwork. CONCLUSION: Therefore, this type of game can enhance students' learning and motivation.

Dental Pulp Defence and Repair Mechanisms in Dental Caries.

Dental caries is a chronic infectious disease resulting from the penetration of oral bacteria into the enamel and dentin. Microorganisms subsequently trigger inflammatory responses in the dental pulp. These events can lead to pulp healing if the infection is not too severe following the removal of diseased enamel and dentin tissues and clinical restoration of the tooth. However, chronic inflammation often persists in the pulp despite treatment, inducing permanent loss of normal tissue and reducing innate repair capacities. For complete tooth healing the formation of a reactionary/reparative dentin barrier to distance and protect the pulp from infectious agents and restorative materials is required. Clinical and in vitro experimental data clearly indicate that dentin barrier formation only occurs when pulp inflammation and infection are minimised, thus enabling reestablishment of tissue homeostasis and health. Therefore, promoting the resolution of pulp inflammation may provide a valuable therapeutic opportunity to ensure the sustainability of dental treatments. This paper focusses on key cellular and molecular mechanisms involved in pulp responses to bacteria and in the pulpal transition between caries-induced inflammation and dentinogenic-based repair. We report, using selected examples, different strategies potentially used by odontoblasts and specialized immune cells to combat dentin-invading bacteria in vivo.

Analyzing the Influence of Video Game and Music Engagement on Technical Skills Acquisition in Dental Students in Preclinical Phase: Protocol for a Prospective, Controlled, Longitudinal Study.

BACKGROUND: The practice of dental surgery requires a few different skills, including mental rotation of an object, precision of movement with good hand-eye coordination, and speed of technical movement. Learning these different skills begins during the preclinical phase of dental student training. Moreover, playing a musical instrument or video game seems to promote the early development of these skills. However, we found that studies specifically addressing this issue in the field of dental education are lacking. OBJECTIVE: The main aims of this study are to evaluate whether the ability to mentally represent a volume in 3D, the precision of gestures with their right and left hand, or the speed of gesture execution is better at baseline or progresses faster for players (video games or music or both). METHODS: A prospective monocentric controlled and longitudinal study will be conducted from September 2023 and will last until April 2025 in the Faculty of Dental Surgery of Nantes. Participants were students before starting their preclinical training. Different tests will be used such as Vandenberg and Kuse's mental rotation test, the modified Precision Manual Dexterity (PMD), and performing a pulpotomy on a permanent tooth. This protocol was approved by the Ethics, Deontology, and Scientific Integrity Committee of Nantes University (institutional review board approval number IORG0011023). RESULTS: A total of 86 second-year dental surgery students were enrolled to participate in the study in September 2023. They will take part in 4 iterations of the study, the last of which will take place in April 2025. CONCLUSIONS: Playing video games or a musical instrument or both could be a potential tool for initiating or facilitating the learning of certain technical skills in dental surgery. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/55738.

Fracture resistance of simulated immature maxillary anterior teeth restored with various canal filling materials, with micro-posts or with a fiber post.

The aim of this in vitro study was to compare the fracture resistance of immature anterior teeth restored with different biomaterials. After preparation of bovine incisors to simulate immature permanent teeth, 98 specimens were assigned into seven groups as follows: G1 -negative control group; G2 -apexification with hydraulic calcium silicate cement in the whole root; G3 -apexification and gutta percha; G4 -apexification and fiber post; G5 -apexification with micro-posts; G6 -apexification with composite; and G7 -revascularization. Both the fracture resistance and the location where the fracture occurred were recorded. Group 4 with a fiber post increased fracture resistance value compared to control (p<0.05). The different tested biomaterials did not influence the location where the fractures occurred among the seven groups (χ21=1.760, p=0.1846).

Physicochemical and biological properties of four calcium silicate-based endodontic cements.

Background/purpose: Several brands of calcium silicate-based cements (CSBCs) are currently marketed. Here we compared physicochemical and biological properties of new products Ortho MTA (BioMTA), Retro MTA (BioMTA), and EZ-Seal (Ezekiel) to widely used ProRoot MTA (Dentsply Tulsa). Materials and methods: CSBCs were analyzed by X-ray diffractometry and examined by scanning electron microscopy. Elemental composition was determined by energy dispersive spectroscopy. Particle size was measured by particle size analyzer. Human stem cells from apical papilla (SCAPs) were incubated with eluates from CSBCs. Survival of SCAP cells was evaluated with MTT assay. The Alizarin red S stain was used to identify calcified nodules formed in SCAP cultures. The effects of CSBC eluates on SCAP proliferation and migration were examined using an in-vitro scratch "wound-healing" assay. Results: All CSBC specimens showed similar X-ray diffraction patterns. The average particle size of EZ-Seal was smaller than ProRoot MTA, Ortho MTA, and Retro MTA (P < 0.001). The least cytotoxicity of eluates was found for EZ-Seal. In the Alizarin red S staining test, calcified nodules were observed in cultures with ProRoot MTA, Ortho MTA, and Retro MTA, however, no calcified nodules were observed in cultures with EZ-Seal. SCAP proliferation and migration capacity in presence of EZ-Seal was higher than with ProRoot MTA, Ortho MTA, and Retro MTA (P < 0.001). Conclusion: EZ-Seal has a smaller average particle size and a better cytocompatibility than all other examined CSBCs.

Anaesthetic efficacy and influence on cardiovascular parameters change of intraosseous computerised anaesthesia versus inferior alveolar nerve block anaesthesia in acute irreversible pulpitis of mandibular molars: study protocol for a prospective randomised controlled trial.

BACKGROUND: Irreversible pulpitis is a highly painful inflammatory condition of the dental pulp. The recommended care is the removal of the coronal pulp (pulpotomy) for emergency treatment in multi-rooted teeth. However, achieving adequate analgesia in the case of mandibular molars presents many difficulties according to the dental literature. Intraosseous computerised anaesthesia (ICA), in particular, the QuickSleeper™ system, has already been demonstrated to be clinically efficient, but ICA is known to increase the heart rate reversibly in a manner that depends on the speed of injection. Therefore, accelerated heart rate was examined as a potential adverse effect of this injection. This trial aims to compare the cardiovascular effects and the anaesthetic efficacy of ICA versus inferior alveolar nerve block anaesthesia (IANB) in acute irreversible pulpitis of mandibular molars. METHODS: This study is a non-inferiority prospective, randomised, controlled, single-blind, two-group trial conducted at the Nantes University Hospital. The study design included two parallel arms at a ratio of 1:1 that will allocate seventy-two patients into two groups: the first group will receive QuickSleeper™ intraosseous anaesthesia; the second will receive an inferior alveolar nerve block before emergency treatment (pulpotomy). This study will include patients requiring emergency dental care under local anaesthesia with confirmed irreversible pulpitis in mandibular molars. The primary outcome is the time taken for the fluctuations in the cardiovascular parameters to return to baseline values during endodontic treatment in two different anaesthetic techniques. The secondary outcomes include efficacy of the technique, patient's pain perception before and after care, any post-operative effects, and factors associated with the delay of recovery of cardiovascular parameters between the 2 anaesthetic techniques. DISCUSSION: This trial will evaluate the factors associated with heart rate increase during local anaesthesia administration. The use of blood pressure and cardiovascular measurements can be considered an asset and additional safety in managing local anaesthesia. Detecting early signs of potential adverse events (AEs), particularly patients with certain medical conditions (cardiac rhythm disorders), would suggest caution in administering anaesthesia. TRIAL REGISTRATION: ClinicalTrials.gov ID: NCT03802305 registered January 14, 2019. (version no. 1.2; 5 November 2021).

Periodontitis, erectile dysfunction, reproductive hormones, and semen quality: A systematic review.

BACKGROUND: There is increasing evidence that periodontitis may affect male sexual health (MSH) (erectile function, production of sex hormones, and semen quality). However, a limited number of clinical studies demonstrate the association between MSH and periodontitis. OBJECTIVES: The aim of this study was to explore the relationship between periodontitis and MSF. MATERIALS AND METHODS: A comprehensive systematic review of the published literature in MEDLINE, PubMed, Scopus, Cochrane, EMBASE, and Web of Science databases from the earliest available online indexing year until October 2020 was performed, in accordance with the PRISMA guidelines. Keywords related to periodontitis were combined with words describing MSH. RESULT: A total of 19 studies were included and discussed in the systematic review. The number of study participants ranged from 53 to 197,136 individuals, aged between 18 and 95 years (mean age, 41.2 years). Six studies did not report the age of the participants. Out of nine studies, eight found a significant association between erectile dysfunction (ED) and periodontitis. Only three studies evaluated the association between sex hormone levels and periodontitis, and two of these studies showed that patients with periodontitis are expected to exhibit higher levels of testosterone. Finally, out of five studies, two demonstrated a significant association between semen quality and periodontitis. DISCUSSION: The findings in this review were limited by the quality and the few available studies. Results from the observational studies might have been affected by recall bias and confounded by cofactors. CONCLUSION: The results of this systematic review revealed a significant association between periodontitis and ED, although the responsible mechanisms remain unclear. The potential associations between sex hormone levels, semen quality, and periodontitis are yet to be demonstrated. In order to improve patient management, dentists and physicians need to be aware of the association between male sexual health problems and periodontitis.

A partially demineralized allogeneic bone graft: in vitro osteogenic potential and preclinical evaluation in two different intramembranous bone healing models.

In skeletal surgical procedures, bone regeneration in irregular and hard-to-reach areas may present clinical challenges. In order to overcome the limitations of traditional autologous bone grafts and bone substitutes, an extrudable and easy-to-handle innovative partially demineralized allogenic bone graft in the form of a paste has been developed. In this study, the regenerative potential of this paste was assessed and compared to its clinically used precursor form allogenic bone particles. Compared to the particular bone graft, the bone paste allowed better attachment of human mesenchymal stromal cells and their commitment towards the osteoblastic lineage, and it induced a pro-regenerative phenotype of human monocytes/macrophages. The bone paste also supported bone healing in vivo in a guide bone regeneration model and, more interestingly, exhibited a substantial bone-forming ability when implanted in a critical-size defect model in rat calvaria. Thus, these findings indicate that this novel partially demineralized allogeneic bone paste that combines substantial bone healing properties and rapid and ease-of-use may be a promising alternative to allogeneic bone grafts for bone regeneration in several clinical contexts of oral and maxillofacial bone grafting.

The Efficiency of the Er: YAG Laser and PhotonInduced Photoacoustic Streaming (PIPS) as an Activation Method in Endodontic Irrigation: A Literature Review.

In the field of endodontics, lasers have been used for a long time for the optimization of Endodontic irrigation in particular. The laser-activated irrigation (LAI) technique is based on the photomechanical effects of the lasers at low settings. They create specific cavitation phenomena and acoustic streaming in intracanal fluids. More recently, a new technique with a Er:YAG laser has been used with sub-ablative energy (20 mJ, 15 Hz) and ultra-short pulses (50 µs). This leads to intracanal cavitation and shockwaves as a result of photoacoustic and photomechanical effects. This phenomenon is called photon-induced photoacoustic streaming (PIPS). PIPS and Laser activated irrigation are described in the literature as a revolutionary and powerful method to activate the irrigant; however, systematic literature on this topic is missing. This review compares the literature on Er:YAG LAI and PIPS on endodontic irrigation with other irrigation methods. An article search was performed on the PubMed database using a series of keywords related to endodontic irrigation, including Er:YAG LAI and PIPS; 59 articles were selected for the review according to the inclusion and exclusion criteria. No in vivo study was found. The Er:YAG LAI and PIPS outperformed other methods in 33 of the 59 articles. There was a great variety in the study designs including bacterial incubation time, laser parameters, irrigation protocols, and irrigating solution used. The evidence suggests that the Er:YAG LAI and PIPS are promising in canal disinfection as well as debris and smear layer removal. However, the large variety in the study methods makes the results less significant. Further studies are needed to better evaluate the efficiency of these techniques, especially in vivo studies.

Cytokine Production and Cytotoxicity of Calcium Silicate-based Sealers in 2- and 3-dimensional Cell Culture Models.

INTRODUCTION: The aim of the present study was to assess the effects of different silicate-based sealers (ie, BioRoot RCS [Septodont, Saint Maur des Fosses, France], ProRoot ES [Dentsply Sirona, York, PA], and MTA Fillapex [Angelus, Londrina, PR, Brazil]) on cytokine production and viability of human periodontal ligament stem cells (PDLSCs). AH Plus (Dentsply DeTrey GmbH, Konstanz, Germany) was used as a reference material. METHODS: PDLSCs were cultured either in 2-dimensional or 3-dimensional conditions (in 0.15%-0.5% PuraMatrix [BD Biosciences, Bedford, MA]) for 24 hours with eluates from set endodontic sealers. Additionally, the toxicity of eluates from endodontic sealers was evaluated using an in vitro root model experimental procedure. PDLSC viability was determined using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assay. PDLSC culture medium was used for cytokine quantification (interleukin [IL]-6, IL-8, growth-regulated oncogene, IL,-4 and IL-10) using the HCYTMAG-60K-PX41 Milliplex kit (EMD Millipore, Burlington, MA). RESULTS: In 2-dimensional culture conditions, BioRoot RCS revealed a good PDLSC viability rate. ProRoot ES had no effect on PDLSC viability regardless of the dilution. MTA Fillapex was strongly cytotoxic even at the lowest extract dilutions (1:1, 1:2, and 1:4). Encapsulation of PDLSCs in PuraMatrix tended to decrease the cytotoxic effect of the sealers. In the 3-dimensional in vitro root model experimental procedure, BioRoot RCS, ProRoot ES, and MTA Fillapex revealed a cytocompatibility pattern. Different calcium silicate-based sealers exhibited different proinflammatory cytokine production. BioRoot RCS greatly stimulated the release of IL-10 and, to a lesser degree, IL-4 by PDLSCs (P < .05). CONCLUSIONS: BioRoot RCS and ProRoot ES did not induce proinflammatory cytokines and promoted anti-inflammatory cytokine secretion by PDLSCs that may have a positive local impact by attenuating an initial inflammatory response.

Periodontal pockets: A potential reservoir for SARS-CoV-2?

Periodontal pockets are the major clinical manifestation of Periodontitis, a chronic inflammatory oral disease affecting the teeth-supporting tissues and has high prevalence in the adult population. Periodontal pockets are ideal environments for subgingival bacterial biofilms, that interact with the supragingival oral cavity, mucosal tissues of the pocket and a peripheral circulatory system. Periodontal pockets have been found to harbor viral species such as the Herpes simplex viruses' family. Recently, the SARS-CoV-2 has gained major interest of the scientific/medical community as it caused a global pandemic (Covid-19) and paralyzed the globe with high figures of infected people worldwide. This virus behavior is still partially understood, and by analyzing some of its features we hypothesized that periodontal pocket could be a favorable anatomical niche for the virus and thus acting as a reservoir for SARS-CoV-2.

Effect of dental caries on periodontal inflammatory status: A split-mouth study.

OBJECTIVE: This controlled split-mouth study aimed to estimate the effect of caries and related treatment on concentrations of interleukin (IL)-2, interferon (IFN)-γ, IL-12, IL-17A, IL-13, IL-10, IL-6, IL-5, IL-4, IL-22, tumor necrosis factor (TNF)-α, and IL1-ß in gingival crevicular fluid (GCF) of caries affected teeth before (B), 7 (7D) and 30 (30D) days post-treatment and to compare them with concentrations from healthy teeth. DESIGN: Study population included 81 systemically and periodontally healthy non-smokers exhibiting at least one shallow occlusal/ inter-proximal caries and one healthy tooth from the same morphologic group at the contralateral position. Following clinical exam, the GCF samples were collected baseline as well as 7D and 30D, while the biomarker measurement was performed using multiplex flowcytometry. RESULTS: Caries affected teeth exhibited significantly higher levels of IFN-γ, IL-1ß, IL-2, IL-4 and IL-6 when compared to healthy teeth. Post-treatment cytokines levels showed general trend of increase when compared to baseline, that was significant for IL-22 and IL-17 at 7D, while IFN-γ was significantly increased at 7D compared to the healthy teeth. At 30D, IFN-γ, TNF-α, IL-17 and IL-4 levels were significantly increased when compared to healthy teeth, while IL-2 levels were significantly higher than baseline levels. CONCLUSION: Considering significantly increased periodontal levels of inflammatory markers in caries affected teeth and in response to performed treatment, it seems that dental caries and related restorative treatment might contribute to periodontal inflammation via additive effects already in early-stage caries.

The Effect of Magnification Loupes on Spontaneous Posture Change of Dental Students During Preclinical Restorative Training.

Scientific evidence validating the beneficial effect of loupes in preventing musculoskeletal disorders is very scarce. The aim of this study was to assess the impact of dental loupes on dental students' posture during a preclinical restorative dentistry course. Using a randomized crossover design, this study was conducted at the School of Dentistry, University of Nantes, France, in 2017. Forty students in their second year of dental study were randomly divided into two groups of 20 each: group A used loupes, whereas group B did not. The week after, students reversed configurations (each subject served as his or her own treatment and control group). Students were video-recorded during cavity preparation. Trunk, head and neck, and upper arm positions were analyzed using continuous scores based on the modified Posture Assessment Instrument. Additionally, cavities were rated, and students completed a questionnaire on their perceptions of the loupes. On a scale on which lower scores indicated better posture, the results showed significantly higher posture ergonomic scores per minute for students without loupes (146.3±6.64 points/min) than with loupes (123.2±6.77 points/min; p<0.05). The majority of the students (32/39, 82%) showed improvements in ergonomic postures with the use of loupes. Trunk, head, and neck were positively impacted by the use of loupes, but not the upper arms. Cavity preparations were not improved by the use of loupes. The questionnaire revealed negative aspects (pain and difficulty adapting) but underlined the perceived positive impact on posture. This study documented the ergonomic advantages and challenges of introducing magnification near the beginning of the dental training program.

Phenotypic analysis of immunocompetent cells in healthy human dental pulp.

INTRODUCTION: Like other tissues in the body, the human dental pulp is equipped with a network of immune cells that can be mobilized against pathogens when they invade the tooth. Very little data, mostly obtained with classic histologic methods, have reported their quantities and relative percentages. The objective of this study was to characterize and precisely quantify immunocompetent cells in healthy human dental pulp by using fluorescence-activated cell sorting, together with identifying specific cell subsets in the leukocyte (CD45(+)) cells. METHODS: Healthy human third molars were collected from 42 young patients. Dental pulps were separated from the hard tissues and prepared for flow cytometry or immunostaining analyses. RESULTS: CD45(+) cells represented 0.94% ± 0.65% of cells obtained from the enzymatic digestion of whole dental pulps (n = 34). CD16(+)CD14(+) granulocytes/neutrophils (50.01% ± 9.08%, n = 7) were found to represent the major subpopulation in CD45(+) cells followed by CD3(+) T lymphocytes (32.58% ± 11%, n = 17), CD14(+) monocytes (8.93% ± 5.8%, n = 7), and HLA-DR(high) Lin1(-) dendritic cells (4.51% ± 1.12%, n = 7). Minor subpopulations included CD3(-)CD56(+) natural killer cells (2.63% ± 1.15%, n = 7) and CD19(+) B lymphocytes (1.65% ± 0.89%, n = 17). We further identified cells harboring a phenotype compatible with Foxp3/CD25-expressing regulatory T lymphocytes (CD45(+)CD3(+)CD4(+)CD127(low)). Fluorescence-activated cell sorting analysis and confocal microscopy also revealed expression of HO-1 in HLA-DR(+) cells. CONCLUSIONS: For the first time, this study identifies and precisely quantifies the relative proportion of immunocompetent cells potentially involved in tissue homeostasis of healthy human dental pulp.