Effect of non-surgical periodontal therapy on risk markers of cardiovascular disease: a systematic review and meta-analysis.

BACKGROUND: Cardiovascular disease (CVD) is the leading cause of mortality in the world. Patients with periodontitis have a higher risk of CVD, although a causal relationship between these conditions remains unclear. Non-surgical periodontal therapy (NSPT) is able to control inflammation at local and systemic levels. This study aimed to analyze the effect of NSPT on CVD risk markers. METHODS: Four electronic databases were searched from their inception to April 1, 2023, to identify and select articles without any language restrictions. Eleven CVD-related markers (e.g., C-reactive protein [CRP], Interleukin-6 [IL-6]) were selected. Meta-analyses were performed using random and fixed effect models. The differences were expressed as weighted mean differences (WMD) and 95% confidence interval (95% CI). RESULTS: From 1353 studies, twenty-one randomized controlled clinical trials were included in the meta-analysis. Results showed a significant decrease in CRP, IL-6, and systolic blood pressure (SBP) after NSPT. CONCLUSION: Moderate certainty evidence shows that NSPT has a positive effect on the reduction of IL-6 and SBP in patients with periodontitis, while low certainty evidence shows that NSPT is effective for reduction of CRP. Moderate certainty evidence showed that NSPT did not show a positive effect on low-density lipoprotein (LDL), high-density lipoprotein (HDL), total cholesterol (TC) and triglycerides (TG), and low certainty evidence showed that NSPT did not show a positive effect on Interleukin-1ß (IL-1ß), tumor necrosis factor-alpha (TNF-α), diastolic blood pressure (DBP), and flow-mediated dilatation (FMD). PROTOCOL REGISTRATION: The protocol was registered in the PROSPERO (International Prospective Register of Systematic Reviews), number CRD42022377565.

Shaping outcome of ProTaper NEXT for root canal preparation in mandibular incisors: a micro-CT study.

BACKGROUND: Relatively high incidence of single canals with oval or round shape were observed in human mandibular incisors. In order to investigate the influence of the root canal morphology on root canal preparation, the shaping outcome of ProTaper NEXT in oval and round canals of mandibular incisors were evaluated by using micro-computed tomography (micro-CT) analysis. METHODS: This experiment was approved by the School Medical Ethics Committee. The sample size calculation was conducted using G*Power software. Intact mandibular incisors with a single canal were selected. Oval canals (2 < aspect ratio (AR) ≤ 4) and round canals (AR ≤ 2) were pair-matched according to canal length, and assigned to two experimental groups (13 per group). ProTaper NEXT was used for root canal preparation for both groups. Untouched canal wall (UCW), root canal morphological parameters and three-dimensional (3D) dentin thickness were evaluated in the entire root canal and each canal third after micro-CT scanning. STATISTICAL ANALYSIS: Data were collected and analyzed with Mann-Whitney test and Friedman test using SPSS statistics software 25 (P < 0.05). Additionally, correlations of UCW area with canal morphological parameters were also investigated. RESULTS: After root canal preparation, no significant difference was observed in all analyzed parameters in the apical third between oval and round canal groups (P > 0.05). In the coronal two thirds of the canal, the post-operative structure model index (SMI), form factor and roundness were significantly increased, while the AR was significantly decreased in both groups (P < 0.05). In addition, in the coronal two thirds, significantly more UCW and higher UCWΔ% was observed in oval canal group (P < 0.05). Furthermore, UCW correlated very strongly to canal major diameter (0.924) and initial volume (0.938), and strongly to canal form factor (- 0.724), minor diameter (0.799) and canal area (0.882). Proximal dentin wall was associated with significantly thinner pre-operative dentin thickness and higher amount of dentin removal after root canal preparation in both oval and round canal groups. CONCLUSIONS: (1) Both types of canals were more conical after root canal preparation, but oval root canals tend to leave more UCW area than round canals in the coronal two thirds of mandibular incisors, which contributes to the challenge for endodontic infection control. (2) Root canal preparation usually results in excessive dentin removal in the proximal dentin wall comparing with buccal and lingual walls in both types of canals of mandibular incisors.

Mechano-chemical coupling of irrigation enhances endodontic biofilm debridement.

The complexity of the root canal system results in areas where mechanical instrumentation is impossible during endodontic treatment. To disinfect these areas, the effect of irrigation on biofilm debridement is of great significance but has not yet been well explored. Using an in vitro Enterococcus faecalis biofilm model and a biofilm reactor, the present study provides a better understanding of the relative contributions of mechanical and chemical effects of irrigation on biofilm removal, as well as the factors influencing their coupling efficiency. The results clearly demonstrate that, the mechanical effect of irrigation alone does not significantly influence the stability of biofilms. However, the mechanical effect promotes biofilm eradication by coupling with the chemical effect. In addition, both the irrigant concentration and the irrigant-biofilm contact time are among the key factors affecting the mechano-chemical coupling. This knowledge may serve to better direct endodontists in designing irrigation regimes during root canal therapy.

Microcomputed tomographic investigation of the trepan bur/microtube technique for the removal of fractured instruments from root canals without a dental operating microscope.

OBJECTIVES: The aim of this study was to evaluate the removal of fractured instruments in mandibular incisor canals by using the trepan bur/microtube technique without a dental operating microscope (DOM). MATERIALS AND METHODS: Thirty-four mandibular incisors were selected, and 5-mm apical segments of #25/.06 taper K3 NiTi instruments were fractured in the apical portion of each canal. Coronal enlargement was performed, and a staging platform was prepared at the coronal aspect of the fractured instrument. Then, a trepan bur was used to expose 1-1.5 mm of the fragmented instrument, and a microtube device was used to withdraw the fragment. Microcomputed tomographic (micro-CT) imaging was used to evaluate the geometric changes in the root canal and dentin. The time required for fractured instrument removal in each sample was recorded, and the results were statistically analyzed with a paired t test. RESULTS: The trepan bur/microtube technique exhibited a success rate of 76.47%, and the average fractured instrument removal time was 8.55 ± 5.81 min. The changes in canal volume and dentin volume from the coronal end of the fractured instrument to 1.5 mm apical to the end were significantly greater than those from the cementoenamel junction (CEJ) to the coronal end of the fractured instrument during fractured instrument removal (P < 0.0001). CONCLUSIONS: The study showed that the trepan bur/microtube technique had a significant impact on geometric changes in the root canal and dentin from the coronal end of the fractured instrument to 1.5 mm apical to the end. CLINICAL RELEVANCE: These findings suggest that the trepan bur/microtube technique may be an optional method for fractured instrument removal from relatively straight canals.

Response and adaptation mechanisms of Apostichopus japonicus to single and combined anthropogenic stresses of polystyrene microplastics or cadmium.

Microplastics (MPs) have become pervasive in marine ecosystems, exerting detrimental effects on marine life. The concurrent presence and interaction of MPs and heavy metals in aquatic environments could engender more insidious toxicological impacts. This study aimed to elucidate the potential impacts and underlying mechanisms of polystyrene microplastics (PS-MPs), cadmium (Cd), and their combined stress (MPs-Cd) on sea cucumbers (Apostichopus japonicus). It focused on the growth, Cd bioaccumulation, oxidative stress responses, immunoenzymatic activities, and metabolic profiles, specifically considering PS-MPs sizes preferentially ingested by these organisms. The high-dose MPs (MH) treatment group exhibited an increase in cadmium bioavailability within the sea cucumbers. Exposure to PS-MPs or Cd triggered the activation of antioxidant defenses and immune responses. PS-MPs and Cd exhibited a synergistic effect on lysozyme (LZM) activity. A total of 149, 316, 211, 197, 215, 619, 434, and 602 differentially expressed metabolites were identified, distinguishing the low-dose MPs (ML), high-dose MPs (MH), low-dose Cd (LCd), low-dose MPs and low-dose Cd (MLLCd), high-dose MPs and low-dose Cd (MHLCd), high-dose Cd (HCd), low-dose MPs and high-dose Cd (MLHCd), high-dose MPs and high-dose Cd (MHHCd) groups, respectively. Metabolomic analyses revealed disruptions in lipid metabolism, nervous system function, signal transduction, and transport and catabolism pathways following exposure to PS-MPs, Cd, and MPs-Cd. Correlation analyses among key differentially expressed metabolites (DEMs) underscored the interregulation among these metabolic pathways. These results offer new perspectives on the distinct and synergistic toxicological impacts of microplastics and cadmium on aquatic species, highlighting the complex interplay between environmental contaminants and their effects on marine life.

The Role of SDF-1α-CXCR4/CXCR7 in Migration of Human Periodontal Ligament Stem Cells.

Background and Objectives: Regenerative endodontic procedures (REPs) are a research hotspot in the endodontic field. One of the biggest problems of REPs is that it is difficult to realize regeneration of pulp-dentin complex and functional reconstruction. The reason is still not clear. We hypothesize that the migration may be different in different dental stem cells. Periodontal ligament stem cells (PDLSCs) may migrate faster than stem cells of apical papilla (SCAPs), differentiating into cementum-like tissue, bone-like tissue and periodontal ligament-like tissue and, finally affecting the outcomes of REPs. Hence, this study aimed to explore the mechanism that regulates the migration of PDLSCs. Methods and Results: After isolating and culturing PDLSCs and SCAPs from human third molars, we compared the migration of PDLSCs and SCAPs. Then we investigated the role of SDF-1α-CXCR4/CXCR7 axis in PDLSC migration. We further investigated the impact of Porphyromonas gingivalis (P. gingivalis) lipopolysaccharide (LPS) on PDLSC migration and the potential mechanism. PDLSCs showed better migration under both noninflammatory and inflammatory conditions than SCAPs. SDF-1α can promote the migration of PDLSCs by elevating the expression of CXCR4 and CXCR7, increasing the interaction between them, promoting expression of ß-arrestin1 and activating the ERK signaling pathway. P. gingivalis LPS can promote the migration of PDLSCs toward SDF-1α through increasing the expression of CXCR4 via the NF-κB signaling pathway, promoting the expression of ß-arrestin1, and activating the ERK signaling pathway. Conclusions: This study helped elucidate the potential reason for the difficulty in forming pulp-dentin complex.

Comparative Effects of Concentrated Growth Factors on the Biological Characteristics of Periodontal Ligament Cells and Stem Cells from Apical Papilla.

INTRODUCTION: During cell-free regenerative endodontic therapy, both stem cells from apical papilla (SCAPs) and periodontal ligament cells (PDLCs) are possible cell sources because of their proximity. Nonetheless, the regenerative ability of PDLCs and SCAPs under the induction of concentrated growth factors (CGFs) remains unclear. METHODS: PDLCs and SCAPs were treated with various concentrations of CGF-conditioned medium (CCM). The effects of CCM with or without Porphyromonas gingivalis lipopolysaccharide (LPS) on cell migration, odonto/osteogenic differentiation, and the expression of inflammatory cytokines were assessed. Dentin matrix transplants composed of PDLCs or SCAPs cell sheets coupled with CGF were put subcutaneously in immunocompromised mice for 8 weeks to explore their regenerative characteristics in vivo. RESULTS: CCM dose dependently enhanced the migration, proliferation, and odonto/osteogenic differentiation of PDLCs and SCAPs. CCM alleviated LPS-inhibited odonto/osteogenic differentiation of PDLCs and SCAPs as well as the LPS-induced up-regulation of inflammatory cytokines. In vivo, the newly regenerated tissue and microvessels formed by PDLCs and SCAPs were significantly increased under the induction of CGF. SCAPs mainly regenerated pulp/dentinlike tissues and a large number of microvessels, whereas PDLCs mainly formed bone/cementumlike structures. CONCLUSIONS: Overall, PDLCs excelled in cell proliferation, migration, and osteogenic differentiation, whereas SCAPs outperformed PDLCs in terms of angiogenic and odontogenic differentiation. The biological differences between PDLCs and SCAPs provided a possible theoretical basis for the formation of bone/cementum/periodontal ligament-like tissues after cell-free regenerative endodontic therapy.

Influence of Endodontic Procedure on the Adherence of Enterococcus faecalis.

INTRODUCTION: The purpose of this study was to investigate the effects of instrumentation and irrigation on the initial adherence of Enterococcus faecalis to root canal dentin and to explore initial microbial adhesion to root filling materials. METHODS: The following specimens were prepared: instrumented and uninstrumented dentin, dentin treated with different irrigation protocols, and root filling materials. The number of E. faecalis cells adhered on dentin was measured. The adhesion force of E. faecalis cells on different materials and the roughness of different surfaces were measured. The contact angle of the surfaces was recorded. The results were analyzed using the t test. RESULTS: Instrumented dentin specimens had a significantly higher amount of E. faecalis adherence than uninstrumented dentin. There were higher numbers of adhering bacteria on the dentin when EDTA was used alone (P < .05) compared with other irrigants alone. The use of chlorhexidine (CHX) as the last irrigant for a certain time resulted in a reduced number of adhering bacteria when the specimens were first exposed to sodium hypochlorite (NaOCl) followed by EDTA. EDTA used alone had the highest adhesion force followed by NaOCl alone and CHX alone (P < .05). Dentin treated with EDTA alone had the highest roughness and contact angle followed by NaOCl alone and CHX alone (P < .05). CHX added as the final irrigant after NaOCl with EDTA irrigation reduced the contact angle (P < .05). Larger amounts of adhering bacteria and higher adhesion force were detected on the surface of gutta-percha and sealer than on the dentin surface (P < .05). CONCLUSIONS: Instrumentation and irrigation alter the initial adherence of E. faecalis to root canal dentin and the surface properties of the dentin as well.

Converting organosulfur compounds to inorganic polysulfides against resistant bacterial infections.

The use of natural substance to ward off microbial infections has a long history. However, the large-scale production of natural extracts often reduces antibacterial potency, thus limiting practical applications. Here we present a strategy for converting natural organosulfur compounds into nano-iron sulfides that exhibit enhanced antibacterial activity. We show that compared to garlic-derived organosulfur compounds nano-iron sulfides exhibit an over 500-fold increase in antibacterial efficacy to kill several pathogenic and drug-resistant bacteria. Furthermore, our analysis reveals that hydrogen polysulfanes released from nano-iron sulfides possess potent bactericidal activity and the release of polysulfanes can be accelerated by the enzyme-like activity of nano-iron sulfides. Finally, we demonstrate that topical applications of nano-iron sulfides can effectively disrupt pathogenic biofilms on human teeth and accelerate infected-wound healing. Together, our approach to convert organosulfur compounds into inorganic polysulfides potentially provides an antibacterial alternative to combat bacterial infections.

Accuracy of Cone-beam Computed Tomography in Measuring Dentin Thickness and Its Potential of Predicting the Remaining Dentin Thickness after Removing Fractured Instruments.

INTRODUCTION: The purpose of this study was to evaluate the accuracy of cone-beam computed tomographic (CBCT) to measure dentin thickness and its potential of predicting the remaining dentin thickness after the removal of fractured instrument fragments. METHODS: Twenty-three human mandibular molars were selected, and 4-mm portions of #25/.06 taper K3 files (SybronEndo, Orange, CA) were fractured in mesial canals. The teeth were then scanned using a micro-computed tomographic (micro-CT) system and a CBCT unit. Dentin thickness was measured and compared between both micro-CT and CBCT images to study the accuracy of CBCT readings. Then, the process of removing the fragments was simulated in CBCT images using the MeVisLab package (MeVis Research, Bremen, Germany); the predicted minimal remaining dentin thickness after removal was measured in different layers using VGStudio MAX software (Volume Graphics, Heidelberg, Germany). Data were compared with the actual minimal remaining dentin thickness acquired from micro-CT images, which were scanned after removing fractured instruments using the microtrepan technique. The results were analyzed statistically using intraclass correlation coefficients (ICCs) and a forecasting regression model analysis. RESULTS: The ICC for the dentin thickness was 0.988. The forecasting regression model of CBCT imaging estimating dentin thickness was micro-CT imaging = 15.835 + 1.080*CBCT, R2 = 0.963. The ICC for the remaining dentin thickness was 0.975 (P < .001). The forecasting regression model of CBCT imaging forecasting remaining dentin thickness was micro-CT imaging = 147.999 + 0.879*adjusted CBCT, R2 = 0.906. CONCLUSIONS: The study showed that CBCT imaging could measure dentin thickness accurately. Furthermore, using CBCT images, it is reliable and feasible to forecast the remaining dentin thickness after simulated instrument removal.