A comparative study of biological properties of three root canal sealers.

OBJECTIVES: The aim of this study was to evaluate the effects of Hiflow with other two kinds of root canal sealers on the biological behavior of stem cells from the apical papilla (SCAP), the influence on inflammatory cytokines release and its antibacterial effects. MATERIALS AND METHODS: Material extracts of Hiflow, iRoot SP, and AH Plus were prepared. Then, SCAP was incubated with extracts. The effects were evaluated by CCK-8, wound healing assay, ALP staining, alizarin red staining, and qRT-PCR. Meanwhile, polymorphonuclears (PMNs) and monocytes were isolated and treated with extracts for 4 h and 24 h respectively. Cell viability was analyzed by Annexin-V/PI double staining flow cytometry. The effects on the release of cytokines were observed by ELISA. The antibacterial effects of different sealers were tested against three kinds of bacteria found in chronic apical periodontitis. RESULTS: A series of results of SCAP showed that Hiflow and iRoot SP could promote cell proliferation, migration, and osteogenesis (p < 0.05). Although Hiflow was associated with greater cell apoptosis and necrosis when incubated with PMNs and monocytes (p < 0.05), it had an approximate release of anti-inflammatory cytokines with iRoot SP, which was higher than AH plus (p < 0.05). The co-culture showed that Hiflow and iRoot SP inhibited the colony formation of F. nucleatum (p < 0.05). However, both sealers had no obvious antibacterial effect on E. faecalis and P. gingivalis (p > 0.05). CONCLUSIONS: In summary, Hiflow and iRoot SP both had positive biological stimulus on SCAP. Meanwhile, Hiflow showed a better induction on anti-inflammatory cytokines over the others. All the properties mentioned above and its antibacterial effect of F. nucleatum promise Hiflow a bright application prospect in endodontic uses. CLINICAL RELEVANCE: References for clinical work to use BC Sealer Hiflow as a good biological root canal sealer.

Microcomputed tomographic analysis of the efficiency of two retreatment techniques in removing root canal filling materials from mandibular incisors.

This study aimed to evaluate the removal effect of the ProTaper Next system (PTN) combined with manual nickel-titanium Hedström (MNiTiH) files or chloroform on filling materials of mandibular incisors by microcomputed tomography (micro-CT). Sixty-four extracted human mandibular incisors were finally selected and assigned to two groups (n = 32) based on root canal morphology after instrumentation. Two subgroups (n = 16) were formed based on two retreatment methods. The volume of residual filling materials (RFMs) and the surface area covered by RFMs were analyzed by micro-CT, the apical extrusion and the time taken for removing the filling materials were recorded. A smaller percentage of the volume of RFMs and less surface area covered by RFMs occurred in PTN combined with MNiTiH groups and round-shaped canal incisors (P < 0.05). The time taken for removing the filling materials was not significantly different in all groups (P > 0.05). The apical extrusion was significantly less in PTN combined with MNiTiH groups than in PTN combined with chloroform groups (P < 0.05). Neither of the two methods rendered root canals completely free from filling materials. PTN combined with MNiTiH could reduce the apical extrusion and remove filling materials more efficiently than PTN combined with chloroform.

Investigation of the antibacterial effect, osteogenic activity, and tracing properties of hydroxyapatite co-doped with Tb3+ and Zn2.

Hydroxyapatite (HA) is a biomimetic biomaterial that has been widely used in bone repair for many years. However, the increased risk of infection after surgery and long-time tracing for the material distribution and degradation during bone reconstruction remain challenges in the clinic. Zinc (Zn) is considered as an indispensable microelement for humans and is characterized with antibacterial action and osteogenic activity. Terbium (Tb), a rare-earth element, emits stable fluorescence under ultraviolet light. Here, Tb3+/Zn2+ co-doped hydroxyapatite (HA:Tb/Zn) was prepared to synchronously realize the antibacterial effect, osteogenic activity, and long-time tracing property. We found that HA:Tb/Zn had a strong antibacterial effect on both Gram-positive and Gram-negative clinical infectious bacteria, as well as improved osteogenic activity. HA:Tb/Zn also displayed stable green fluorescence in vitro and in vivo, which indicated great potential for recognizing the material changes during the bone reconstruction process. The combination of the ternary functions is of great significance to control the overuse of antibiotics and realize long-time tracing, and provide a versatile design on biomaterials in bone repair.

The landscape of endodontic education research area: A bibliometric analysis.

OBJECTIVES: Educational research is essential for rationalizing curriculum design, improving evaluation systems, and updating teaching content. This bibliometric study aimed at analyzing the characteristics of publications relevant to endodontic education, thus forming a comprehensive scope of this research area. METHODS: The search was conducted in the Web of Science Core Collection database in May 2022. Knowledge units of the included publications, such as year of publication, journal, country/institution/author, keywords, and highly cited articles/references, were analyzed. RESULTS: The United States ranked first in the number of articles with a total of 17 articles. The majority of included articles were published in Journal of Dental Education (n = 25), International Endodontic Journal (n = 21), and European Journal of Dental Education (n = 14). The top 3 most frequent keywords were Endodontics, Education, and Root canal treatment. The main topic in endodontic education were curriculum, preclinical education, educational technology, and continuing education. CONCLUSION: Forming a full scope of the endodontic research area, this bibliomertic analysis can help mine the hot topic, predict the frontiers in the field and provide the data necessary to determine the direction of research, rationalize resource allocation, and formulate policy.

A Bibliometric Analysis of Studies on Root Caries.

This study aimed to review the current state of the root caries field, explore the current hot topic, and anticipate future research frontiers. The Web of Science Core Collections was searched to acquire publications that were relevant to root caries from 1992 to 2021. After retrieval and manual screening, the co-occurrence and co-operation analysis of keywords and countries/institutions/authors were performed through CiteSpace and VOSviewer based on two periods (1992-2006 and 2007-2021). From 1992 to 2021, 451 unique publications were selected. The USA, which has been the center of international cooperation, has produced the most publications in the research area in 1992-2021. Journal of Dental Research and Caries Research are the main counterpart journals in the field of root caries. The University of London is the institution with the highest number of publications in the analyzed 30 years. "Demineralization," "remineralization," "aged," "dentin," and "fluoride" have been commonly used as keywords throughout the past 30 years. More studies from different aspects have been published in the field of root caries in recent years (2007-2021). The findings of this study provide a full picture of the last 30 years in this research area; hopefully, they also provide essential information for researchers and policymakers to make decisions.

Assessment of the Effectiveness of Supplementary Methods for Residual Filling Material Removal Using Micro-computed Tomography: A Systematic Review and Meta-analysis of In Vitro Studies.

A systematic review and meta-analysis were conducted to evaluate the effectiveness of auxiliary methods in removing residual filling material (RFM). This systematic review has been registered with the International Prospective Register of Systematic Reviews (registration number CRD42020197482). A comprehensive literature search was conducted to identify relevant articles in electronic databases (PubMed, Embase, Cochrane) from January 2005 to March 2021. In vitro studies investigating or comparing at least one type of supplementary method or technique were included. A total of 26 studies were selected from the 239 records obtained after screening the databases. Ten of the included studies were suitable for meta-analysis. Strong evidence showed that ultrasonically activated irrigation (UAI) [SMD (95% CI): -0.52 (-0.88 to -0.16, P=0.266)] and XP-Endo Finisher R (XPR) [SMD (95% CI): -0.55 (-0.89 to -0.20, P=0.136)) contributed significantly to increase the removal procedure, and XPR has no significant superiority over UAI [SMD (95% CI): 0.36 (-0.12 to 0.84, P=0.994)]. Strong evidence was found to support the increased cleaning efficiency of the supplementary use of the Gentle Wave system, laser irradiation, XP Endo Finisher, and self-adjusting file. In contrast, conflicting evidence was found to support the use of sonic to improve the removal of RFM, and limited evidence was found to support the efficiency of Tornado Brush. Under in vitro conditions, UAI and XPR increase the removal of RFM from the root canal system during retreatment procedures.

An in vitro evaluation of antimicrobial activity of a fast-setting endodontic material.

The aim of this study is to evaluate the antimicrobial activity of the fast-setting iRoot Fast Set Root Repair Material (iRoot FS), Mineral trioxide aggregate (MTA) and Biodentine. The materials were freshly mixed or set for 1 and 7 days to conduct the agar diffusion test, direct contact test and carry-over effect test against E. faecalis and P. gingivalis, and the pH values were also measured. The data were analyzed by an analysis of variance and one-way ANOVA or Dunnett's T3 test, and the Tukey's post hoc test for multiple comparisons (α = 0.05). In the direct contact test, all three materials showed good antibacterial activity after setting for 20 min. The antibacterial properties of the three materials decreased with the increase of setting time (p < 0.05). The suspension of all the three materials showed high pH values (11-12) and no significant difference was observed (p > 0.05). With the extension of setting time, the pH of iRoot FS and Biodentine slightly decreased (p < 0.05). Fresh iRoot FS, Biodentine, and MTA killed E. faecalis and P. gingivalis effectively, but their antimicrobial effect decreased after 24 h, and distinctly decreased after 7 days after mixing. iRoot FS, Biodentine, and MTA showed a tendency of alkalinity during this 7-day experiment.

Natural products from traditional medicine as promising agents targeting at different stages of oral biofilm development.

Oral cavity is an ideal habitat for more than 1,000 species of microorganisms. The diverse oral microbes form biofilms over the hard and soft tissues in the oral cavity, affecting the oral ecological balance and the development of oral diseases, such as caries, apical periodontitis, and periodontitis. Currently, antibiotics are the primary agents against infectious diseases; however, the emergence of drug resistance and the disruption of oral microecology have challenged their applications. The discovery of new antibiotic-independent agents is a promising strategy against biofilm-induced infections. Natural products from traditional medicine have shown potential antibiofilm activities in the oral cavity with high safety, cost-effectiveness, and minimal adverse drug reactions. Aiming to highlight the importance and functions of natural products from traditional medicine against oral biofilms, here we summarized and discussed the antibiofilm effects of natural products targeting at different stages of the biofilm formation process, including adhesion, proliferation, maturation, and dispersion, and their effects on multi-species biofilms. The perspective of antibiofilm agents for oral infectious diseases to restore the balance of oral microecology is also discussed.

The Arginine Biosynthesis Pathway of Candida albicans Regulates Its Cross-Kingdom Interaction with Actinomyces viscosus to Promote Root Caries.

The cross-kingdom interactions between Candida albicans and Actinomyces viscosus play critical roles in root caries. However, the key pathway by which C. albicans regulates its interactions with A. viscosus is unclear. Here, we first employed 39 volunteers with root caries and 37 caries-free volunteers, and found that the abundances of C. albicans and A. viscosus were significantly increased in the individuals with root caries and showed a strong positive correlation. Their dual-species combination synergistically promoted biofilm formation and root caries in rats. The arginine biosynthesis pathway of C. albicans was significantly upregulated in dual-species biofilms and dental plaques from another 10 root caries volunteers compared with the 10 caries-free volunteers. The exogenous addition of arginine increased the cariogenicity of the dual-species biofilm. The C. albicans ARG4, a key gene from the arginine biosynthesis pathway, null mutant failed to promote dual-species biofilm formation and root caries in rats; however, the addition of arginine restored its synergistic actions with A. viscosus. Our results identified the critical roles of the C. albicans arginine biosynthesis pathway in its cross-kingdom interactions with A. viscosus for the first time and indicated that targeting this pathway was a practical way to treat root caries caused by multiple species. IMPORTANCE Root caries is a critical problem that threatens the oral health of the elderly population. Our results identified the essential roles of the C. albicans arginine biosynthesis pathway in its cross-kingdom interactions with A. viscosus in root caries for the first time and indicated that targeting this pathway was a practical way to treat root caries caused by multiple species.

Anticaries activity of GERM CLEAN in Streptococcus mutans and Candida albicans dual-species biofilm.

OBJECTIVE: To evaluate the antimicrobial effects of a peptide containing novel oral spray GERM CLEAN on dual-species biofilm formed by Streptococcus mutans and Candida albicans and to investigate whether GERM CLEAN inhibits the demineralization procedure of bovine enamel in vitro. METHODS: The antimicrobial effects of GERM CLEAN on dual-species biofilm were analyzed by initial adherence rate calculation, water-insoluble exopolysaccharides quantification, total biomass quantification, and colony-forming units (CFUs) counting. Scanning electron microscopy and confocal laser scanning microscopy were applied to evaluate the impacts of GERM CLEAN on the biofilm structure. Further, the effects of GERM CLEAN on acidogenicity of dual-species were appraised via glycolytic pH drop analysis and hydroxyapatite dissolution measurement. The percentage of Surface Microhardness Reduction (%SMHR) evaluation, Atomic Force Micrograph (AFM) examination, and Transverse Microradiography (TMR) analysis after pH cycling were used to determine whether GERM CLEAN inhibited the demineralization of bovine enamel. RESULTS: GERM CLEAN decreased the adherence rate, water-insoluble EPS production, biofilm formation, and acidogenicity of the dual-species. Moreover, GERM CLEAN significantly inhibited the demineralization status of bovine enamels. CONCLUSION: This peptide containing novel oral spray GERM CLEAN has antimicrobial potential toward the dual-species. GERM CLEAN can also impede the demineralization procedure of enamel.

Rapid detection of human heart-type fatty acid-binding protein in human plasma and blood using a colloidal gold-based lateral flow immunoassay.

The incidence of acute myocardial infarction (AMI) is currently increasing. Early detection is important for the treatment and prognosis of patients with AMI. Heart-type fatty acid-binding protein (H-FABP) may be used as an early marker of AMI due to its high sensitivity, specificity and prognostic value. Therefore, in the present study, H-FABP was used as a biomarker in a double-antibody sandwich method and colloidal gold-based lateral flow immunoassay to develop a rapid detection kit for H-FABP with a processing time of only 5 min. The sensitivity of the kit in plasma and whole blood was 1 ng/ml and this method had good specificity, exhibiting no cross-reaction with cardiac troponin I, myoglobin or creatine kinase-Mb. The kits had good shelf life and stability, as they were able to be stored at 40˚C for 30 days. A total of 12 clinical samples were collected for detection and the coincidence rate with the ELISA method was up to 91.67%. Therefore, the present study provided a simple, rapid and economical early-detection in-home testing kit.