Systematic review and meta-analysis of root morphology and canal configuration of permanent premolars using cone-beam computed tomography.

INTRODUCTION: The efficacy of root canal treatment is greatly impacted by a thorough understanding of root canal anatomy. This systematic review and meta-analysis aim to thoroughly investigate the root morphology and canal configuration (RMCC) of permanent premolars (PMs). METHODOLOGY: A comprehensive analysis was conducted following the PRISMA guidelines. Literature exploration was carried out across four electronic databases (PubMed, Embase, Cochrane, and Web of Science). The risk of bias assessment was conducted for the included studies utilizing the Anatomical Quality Assessment (AQUA) tool. Data analysis was performed utilizing SPSS and RevMAN5.3.3. The meta-analysis was applied with a 95% confidence interval to calculate odds ratios (OR). RESULTS: Among the 82 selected studies, 59 studies exhibited potential bias in domain one (objective(s) and subject characteristics), followed by domain three (methodology characterization). The majority of maxillary PM1s had either single root (46.7%) or double roots (51.9%), while three-rooted variants were uncommon (1.4%). Conversely, most other PMs exhibited a single root. In terms of canal configuration, maxillary PM1s predominantly featured double distinct canals (87.2%), with the majority of maxillary PM2s displaying either a single canal (51.4%) or double canals (48.3%). Mandibular PMs were primarily characterized by single canals, accounting for 78.3% of mandibular PM1s and 90.3% of mandibular PM2s. Subgroup analyses revealed higher incidences of single-rooted and single-canalled PMs among Asians compared to Caucasians. Additionally, women exhibited a higher incidence of single-rooted PMs, while men showed a greater frequency of double-rooted PMs. CONCLUSIONS: The comprehensive analysis indicated that maxillary PM1s predominantly possess double roots and double canals, whereas maxillary PM2s and mandibular PMs were primarily characterized by single-rooted with a single canal. Notably, single root and single canal were more prevalent among women and Asian samples.

iTRAQ-Based Differential Proteomic Analysis Reveals the Pathways Associated with Tigecycline Resistance in Acinetobacter baumannii.

BACKGROUND/AIMS: Acinetobacter baumannii is an aerobic and Gram-negative bacterial pathogen with high morbidity and mortality. It remains a serious public health problem arising from its multidrug-resistant and extensive antibiotic resistance spectrum. METHODS: In the present study, iTRAQ coupled with 2D LC-MS/MS was used to evaluate the proteome in standard Acinetobacter baumannii standard strains and tigecycline-resistant strains. RESULTS: A total of 3639 proteins were identified and 961 proteins were identified to be differentially expressed in tigecycline-resistant Acinetobacter baumannii strains compared to the standard strains. 506 (52.6%) proteins were up-regulated and 455 (47.4%) proteins were down-regulated. Based on the GO enrichment analysis and KEGG pathway analysis, we concluded that most differentially expressed proteins were associated with stress responses, cellular component organization, proteins synthesis, degradation and function. Moreover, ß-lactam resistance, the longevity regulating pathway and other related pathways were also involved in the regulation of tigecycline-resistant Acinetobacter baumannii. The differential expression of key proteins were evaluated by transcript analysis using quantitative RT-PCR. CONCLUSION: These results may provide new insights into the mechanisms of drug resistance in Acinetobacter baumannii.

An antibacterial chitosan-based hydrogel as a potential degradable bio-scaffold for alveolar ridge preservation.

Post-extraction, preventing the absorption of alveolar ridge to retain the supporting construction for implanted teeth is still a challenge. Herein, we developed modified chitosan (CS)-based hydrogel using N-hydroxysuccinimide-terminated 4-arm poly (ethylene glycol) (4-arm-PEG-NHS) as the crosslinking agent, after introducing it to the polyhexamethyleneguanidine hydrochloride (PHMB) solution, CS/PEG/PHMB hydrogel with the enhanced antibacterial properties was obtained. The CS/PEG hydrogel and CS/PEG/PHMB hydrogel prepared here showed excellent mechanical strength and their compressive strength could reach 440 kPa and 450 kPa, respectively. The composite hydrogel was designed to be directional porous, low cytotoxic, pH-sensitive, and degradable. The weight of the hydrogel was reduced by ∼30% after 28 days of incubation, and it swelled significantly in the acidic condition while it did not swell in the neutral and weakly alkaline environments, indicating an excellent biodegradability in the inflammation site. In vitro antibacterial experiments showed that the bacteriostatic rate of the CS/PEG/PHMB hydrogel against S. aureus was above 90%, which could effectively inhibit the spread of the bacteria and inflammation in the alveolar ridge. Additionally, the hybrid hydrogels demonstrated good biocompatibility with the NIH 3T3 fibroblast cells. Overall, the CS/PEG/PHMB hydrogel is a promising biological scaffold for maintaining the alveolar ridge and subsequently improving the success rate of the dental implant.

NIR-â ¡ window Triple-mode antibacterial Nanoplatform: Cationic Copper sulfide nanoparticles combined vancomycin for synergistic bacteria eradication.

The widespread use of antibiotics leads to the increasing drug resistance of bacteria and poses a threat to human health. Therefore, there is an urgent need to develop new antibacterial strategies. Herein, based on the good photothermal properties of Copper sulfide (CuS) nanoparticles under near infrared (NIR) laser, we developed a NIR-Ⅱ window triple-mode synergetic antibacterial cCuS (cationic CuS) @Vancomycin (Van) nanoplatform. In the proposed nanoplatform, the positive charge on the surface makes cCuS@Van nanoplatform show better bacterial uptake and membrane damage; vancomycin induces chemical sterilization and provides a targeting effect to the nanoplatform; combined with the strong photothermal effect and deep tissue penetration at the excitation of 1064 nm laser, cCuS@Van nanoplatform can effectively kill bacterial. The photothermal conversion efficiency of the nanoplatform can reach 49.12 % and in vitro experiments show a sterilizing rate of more than 99.5 % to staphylococcus aureus (S. aureus) at the concentration of 3.0 µM, which also demonstrated the synergistic effect of cCuS@Van nanoplatform. In addition, low cytotoxicity to human cells conforms the good biocompatibility of the as-prepared cCuS@Van nanoplatform, which endows it a good application prospect in the field of antibacterial, such as wound healing and implant sterilization.

CuS nanoparticles anchored to g-C3N4 nanosheets for photothermal ablation of bacteria.

Antibiotic resistance has already been recognized as one of the greatest threats to human beings' health, and thus it is highly desirable to develop new bactericidal approaches. The photothermal antibacterial process based on the photo-to-thermal conversion using semiconducting materials is currently extensively studied owing to its high efficiency, long durability and environmental benignity. In this study, we fabricated copper sulfide (CuS) nanoparticle-decorated graphitic carbon nitride (g-C3N4) nanosheets, denoted as the PEG-CuS@g-C3N4 nanocomposite, via a simple hydrothermal process. Materials characterization showed that CuS nanoparticles were uniformly distributed on the surface of g-C3N4 without agglomeration. Moreover, the nanocomposite exhibited excellent photothermal conversion efficiency (up to 59.64%) due to its strong near-infrared (NIR) absorption characteristics. The antibacterial efficiency evaluation indicated that the PEG-CuS@g-C3N4 nanocomposite could effectively kill the Gram-positive Staphylococcus aureus (S. aureus) and the Gram-negative Escherichia coli (E. coli). We found that up to 99% of both S. aureus and E. coli could be killed in a 200 µg ml-1 PEG-CuS@g-C3N4 suspension within 20 min of NIR irradiation. Moreover, the cytotoxicity of the PEG-CuS@g-C3N4 nanocomposite was evaluated using the mouse skin fibroblast NIH-3T3 cells, and the nanocomposite was found to display acceptable biocompatibility. We believe that the PEG-CuS@g-C3N4 nanocomposite is of significant interest for rapid bacteria-killing, and would gain promising applications for sterilization.