NLRP3 inflammasome activity and periodontal disease pathogenesis-A bidirectional relationship.

OBJECTIVE: Periodontitis is an inflammatory oral disease that occurs as a result of the damaging effects of the immune response against the subgingival microflora. Among the mechanisms involved, the nucleotide-binding oligomerization domain, leucine-rich repeat-containing proteins family member NLRP3 (NLR family pyrin domain-containing 3), proposed as the key regulator of macrophage-induced inflammation, is strongly associated with periodontal disease due to the bacterial activators. This paper aimed to present key general concepts of NLRP3 inflammasome activation and regulation in periodontal disease. METHOD: A narrative review was conducted in order to depict the current knowledge on the relationship between NLRP3 inflammasome activity and periodontal disease. In vitro and in situ studies were retrieved and commented based on their relevance in the field. RESULTS: The NLRP3 inflammasome activity stimulated by periodontal microbiota drive periodontal disease pathogenesis and progression. This occurs through the release of proinflammatory cytokines IL-1ß, IL-18, and DAMPs (damage-associated molecular pattern molecules) following inflammasome activation. Moreover, the tissue expression of NLRP3 is dysregulated by oral microbiota, further exacerbating periodontal inflammation. CONCLUSION: The review provides new insights into the relationship between the NLRP3 inflammasome activity and periodontal disease pathogenesis, highlighting the roles and regulatory mechanism of inflammatory molecules involved in the disease process.

Shaping Efficiency of Rotary and Reciprocating Kinematics of Engine-driven Nickel-Titanium Instruments in Moderate and Severely curved Root Canals Using Microcomputed Tomography: A Systematic Review of Ex Vivo Studies.

INTRODUCTION: This systematic review aimed to compare reciprocating with continuous rotary instrumentation kinematics, by means of microcomputed tomography evaluations, in extracted human permanent teeth with moderate and severe canal curvatures. METHODS: The research protocol was registered in the International Prospective Register of Systematic Reviews and given the reference number CRD42023404035. An electronic search was undertaken in MEDLINE (PubMed), EBSCO, Scopus, Web of Science databases until December 2021. Manual screening of issues in endodontic journals and references of relevant articles were assessed individually. The risk of bias (RoB) of the included articles was evaluated with the QUIN tool (Quality Assessment Tool for In Vitro Studies). RESULTS: Among 1640 retrieved articles, 49 were included in the qualitative synthesis. Fifteen articles had low RoB, 33 articles had medium RoB, and only 1 study was at high RoB. Continuous rotary systems had better centering ability in both moderate and severe canal curvatures and resulted in less apical transportation in severely curved root canals. None of the kinematic systems was capable of instrumenting the entire canal surface area. Reciprocating kinematics systems tended to provide higher increase in surface area of severely curved canals and produced fewer dentinal microcracks in moderately curved canals. CONCLUSIONS: The evidence presented in this review suggests that continuous rotary system seems to be better than reciprocating system in solving the major issues encountered during root canal instrumentation of extracted teeth with moderate and severe curvatures.

A core curriculum in the biological and biomedical sciences for dentistry.

INTRODUCTION: The biomedical sciences (BMS) are a central part of the dental curriculum that underpins teaching and clinical practice in all areas of dentistry. Although some specialist groups have proposed curricula in their particular topic areas, there is currently no overarching view of what should be included in a BMS curriculum for undergraduate dental programmes. To address this, the Association for Dental Education in Europe (ADEE) convened a Special Interest Group (SIG) with representatives from across Europe to develop a consensus BMS curriculum for dental programmes. CURRICULUM: This paper summarises the outcome of the deliberations of this SIG and details a consensus view from the SIG of what a BMS curriculum should include. CONCLUSIONS: Given the broad nature of BMS applied to dentistry, this curriculum framework is advisory and seeks to provide programme planners with an indicative list of topics which can be mapped to specific learning objectives within their own curricula. As dentistry becomes increasingly specialised, these will change, or some elements of the undergraduate curriculum may move to the post-graduate setting. So, this document should be seen as a beginning and it will need regular review as BMS curricula in dentistry evolve.

Mineralogical and Microstructural Characteristics of Two Dental Pulp Capping Materials.

This paper aims to investigate the composition, surface, and microstructural characteristics, and bioactivity of two commercially available pulp capping materials known as TheraCal LC and BIO MTA+. The materials were prepared as cylindrical samples and assessed by X-ray diffraction (XRD) and complex thermal analysis for mineralogical characterization, and by scanning electron microscopy (SEM) coupled with energy dispersive of X-ray (EDX), Fourier-Transformed Infrared Spectroscopy (FT-IR), and atomic force microscopy (AFM) for microstructural and surface characteristics. The in vitro bioactivity was highlighted by surface mineralization throughout SEM coupled with EDX and FT-IR analysis. XRD analysis performed on both materials showed calcium silicate phases and different radiopacifying compounds. AFM measurements indicated a smoother and more homogenous surface with a lower average roughness for TheraCal LC due to the resin matrix from its composition. FT-IR analysis displayed bands for several compounds in both materials. Both materials exhibited bioactive properties showing surface mineralization after being immersed in solution similar to the human physiological environment. However, the MTA cement showed a better mineralization due to the anhydrous and hydrated phases.

The effect of dental pulp-capping materials on hard-tissue barrier formation: A systematic review and meta-analysis.

BACKGROUND: The authors of this systematic review aimed to compare the effects of pulp-capping materials on hard-tissue barrier formation using histologic assessments. TYPE OF STUDIES REVIEWED: The authors included randomized controlled trials and controlled clinical trials in humans, with vital therapies performed on healthy permanent teeth undergoing experimental mechanical pulp exposures. They searched electronically in the PubMed, Cochrane, Embase, and Summon databases and carried out a manual search. Twenty-seven full-text articles were eligible for inclusion in the systematic review. After data extraction, the authors performed 2 sets of meta-analyses with odds ratios (OR) and their 95% confidence intervals (CI) on 22 studies. Ten studies compared mineral trioxide aggregate (MTA) with calcium hydroxide (CH), and 12 compared bonding agents with CH. The authors assessed bias by means of Cochrane Collaboration's tool for assessing risk, funnel plots, and Harbord test. RESULTS: The use of MTA was associated with a higher rate of hard-tissue barrier formation than CH. The OR comparing the 2 groups was 2.45 (95% CI, 1.39 to 4.29; P = .002). Use of bonding agents was associated with a lower rate of hard-tissue barrier formation than CH. The OR comparing the 2 groups was 0.02 (95% CI, 0.01 to 0.05; P < .001). CONCLUSIONS AND PRACTICAL IMPLICATIONS: The results suggest that MTA and CH have positive effects on hard-tissue barrier formation. On the basis of the evidence, the authors conclude that MTA has better effects than CH regarding dental pulp protection in the capping of mechanical pulp exposures. Conversely, bonding agents are inferior to CH.

Tracheal telocytes.

Recently, a novel type of stromal cell - the telocytes (TC) - was identified in mouse trachea. These cells are known to possess the ultrastructural characteristics, which support their role in intercellular signaling. We found TC in all stromal compartments of the tracheal wall. TC with long prolongations (telopodes, Tp) were lining longitudinally the collagen bundles, and were serially arranged (end-to-end connections of Tp were found). Noteworthy, Tp frequently establish stromal synapses with mast cells (MC). Primary cilia were also identified in TC. In conclusion, tracheal TC could be involved in the tracheal regulation (e.g. secretion, contractility). The tandem TC-MC deserves further investigations.

Respiratory pathogens in dental plaque of hospitalized patients with chronic lung diseases.

Bacterial cultivation studies have shown that dental plaque is a reservoir for respiratory pathogens in intensive care unit patients and in elderly who are debilitated, hospitalized or in a nursing home, placing them at risk of bacterial pneumonia. No information is available, however, concerning dental plaque as a reservoir of putative respiratory pathogens in hospitalized patients with chronic lung diseases. Supragingival plaque colonization of 34 hospitalized chronic lung-diseased Romanian citizens, excluding those with tuberculosis and less than 20 teeth, was therefore assessed by checkerboard DNA-DNA hybridization using a selected panel of whole genomic DNA probes produced from eight respiratory pathogens and eight oral pathogens. Thirty-one lung-healthy dental outpatients served as reference population. Respiratory pathogens were detected in plaque from 29 of the 34 (85.3%) hospitalized patients and 12 of the 31 (38.7%) reference population subjects. Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter baumannii, and Enterobacter cloacae occurred significantly (p<0.05) more frequent among the hospitalized patients. Hospitalized chronic lung-diseased patients harbored in their supragingival plaque samples bacteria known to cause nosocomial pneumonia significantly (p<0.001) more frequent than lung-healthy dental outpatients. Our results indicate that dental plaque in patients with chronic lung diseases often serves as a reservoir of bacteria known to cause nosocomial pneumonia in susceptible individuals.