Nanoarchitectonics-Based Materials as a Promising Strategy in the Treatment of Endodontic Infections.

Endodontic infections arise from the interactive activities of microbial communities colonizing in the intricate root canal system. The present study aims to update the latest knowledge of nanomaterials, their antimicrobial mechanisms, and their applications in endodontics. A detailed literature review of the current knowledge of nanomaterials used in endodontic applications was performed using the PubMed database. Antimicrobial nanomaterials with a small size, large specific surface area, and high chemical activity are introduced to act as irrigants, photosensitizer delivery systems, and medicaments, or to modify sealers. The application of nanomaterials in the endodontic field could enhance antimicrobial efficiency, increase dentin tubule penetration, and improve treatment outcomes. This study supports the potential of nanomaterials as a promising strategy in treating endodontic infections.

Antimicrobial photodynamic therapy against oral biofilm: influencing factors, mechanisms, and combined actions with other strategies.

Oral biofilms are a prominent cause of a wide variety of oral infectious diseases which are still considered as growing public health problems worldwide. Oral biofilms harbor specific virulence factors that would aggravate the infectious process and present resistance to some traditional therapies. Antimicrobial photodynamic therapy (aPDT) has been proposed as a potential approach to eliminate oral biofilms via in situ-generated reactive oxygen species. Although numerous types of research have investigated the effectiveness of aPDT, few review articles have listed the antimicrobial mechanisms of aPDT on oral biofilms and new methods to improve the efficiency of aPDT. The review aims to summarize the virulence factors of oral biofilms, the progress of aPDT in various oral biofilm elimination, the mechanism mediated by aPDT, and combinatorial approaches of aPDT with other traditional agents.

Clinical observation of autologous platelet rich fibrin assisted revascularization of mature permanent teeth.

OBJECTIVE: To investigate the clinical observation of autologous platelet-rich fibrin (PRF) assisting the revascularization of mature permanent teeth. METHODS: Twenty patients with mature permanent teeth were divided into experimental group and control group. The control group was treated with classic revascularization, and the experimental group was treated with PRF-assisted mature permanent tooth revascularization. RESULTS: After treatment, the total effective rate of the experimental group (100.00%) was higher than that of the control group (50.00%); the thickness of the root canal wall of the experimental group was higher than that of the control group, and the crown root length was lower than that of the control group; The bite degree, chewing function, color, overall aesthetic score, and satisfaction rate of the patients were higher, and the difference was statistically significant (P < 0.05). CONCLUSION: Autologous PRF assists in revascularization of mature permanent teeth, which can achieve ideal results, and promote pulp regeneration.

Is oxidative stress involved in the hepatic inflammatory response to apical periodontitis? A comparative study in normal and hyperlipidaemic rat.

AIM: The aim of the study was to explore the involvement of oxidative stress (OS) in the hepatic inflammation induced by apical periodontitis (AP). Periapical, systemic and hepatic reaction to AP under hyperlipidaemia was also investigated. METHODOLOGY: A total of 16 male Sprague-Dawley rats were fed with a hyperlipidaemic diet (HD) whereas another 16 rats with a normal diet (ND). After 9 weeks, the first molars of the right maxilla and mandible of 8 HD and 8 ND rats were exposed to induce AP (ND, ND + AP, HD and HD + AP group). After 5 weeks, rats were euthanized, the haematological tissue was collected directly from the heart, and serum levels of inflammatory cytokines were measured. Liver tissue was analysed by haematoxylin-eosin and Masson staining, and reverse transcription-polymerase chain reaction (RT-PCR) was performed to detect mRNA expression of inflammatory cytokines. Serum, periapical, and hepatic OS parameters including total oxidant status (TOS), total antioxidant capacity (TAOC) and oxidative stress index (OSI) were measured by enzyme-linked immunosorbent assay (ELISA). The area of AP lesion in the right maxilla or mandible was radiographically assessed. Student's t-test was performed on the periapical data. A one-way analysis of variance and the Kruskal-Wallis test were analysed for others. RESULTS: The HD + AP group had a larger AP lesion in the maxilla, compared with the ND + AP group (p < .05). The ND + AP group presented higher serum interleukin (IL)-18, IL-1ß, TOS, OSI levels, lower serum TOAC levels, higher hepatic tumour necrosis factor (TNF)-α mRNA expression and higher hepatic TOS, and OSI levels, compared with the ND group (p < .05). The HD + AP group had lower serum IL-4 level, higher serum IL-1ß level, and higher hepatic IL-6 and transforming growth factor (TGF) -ß1 mRNA expression, compared with the HD group (p < .05). CONCLUSIONS: Apical periodontitis could activate systemic and liver inflammation by promoting serum IL-18, 1L-1ß, TOS and OSI expression, enhancing hepatic TOS and OSI expression and inhibiting serum TOAC expression. AP under hyperlipidaemia led to more profound periapical bone destruction in the maxilla and elicit systemic and liver inflammatory responses through elevating serum levels of IL-1ß, descending serum IL-4 level and improving hepatic IL-6 and TGF-ß1 expression.

Effects of chronic apical periodontitis on the inflammatory response of the aorta in hyperlipemic rats.

OBJECTIVES: To study the effects of chronic apical periodontitis (CAP) on the inflammatory response and initial lesion of aorta in hyperlipemic rats. MATERIALS AND METHODS: Sprague-Dawley (SD) rats aged 14 weeks were randomly divided into 4 experimental groups (n = 8), namely, normal diet (ND), high-fat diet (HFD), CAP, and HFD + CAP. The rats were raised under controlled conditions and fed with diet specified for each group. All subjects were euthanatized after 14 weeks for histopathological analysis. Serum cytokines were analyzed to assess changes in gene and protein expression of aorta via enzyme-linked immunosorbent assay and real-time polymerase chain reaction. Results were analyzed by one-way ANOVA. RESULTS: Low-density lipoprotein cholesterol levels in rats in HFD + CAP group were significantly higher than those in other groups. By comparison, low-density lipoprotein cholesterol levels in rats in both the HFD and HFD + CAP groups were significantly lower than those in the other groups. No significant difference among all groups was observed in terms of CRP level. However, levels of IL-2, IL-6, and IL-10 increased in the experimental CAP rats compared with the control rats. mRNA expression levels of MCP-1, TLR-4, and NF-κB p65 were markedly elevated in rats in the HFD group compared with those in rats in the ND group. TLR-4 mRNA expression was significantly higher in rats in the HFD + CAP group than that in rats in the HFD group. CONCLUSIONS: CAP mediated the high expression of cytokines and induced the initial inflammatory response in the aorta. Apical periodontitis may affect the level of inflammatory cytokines (IL-2, IL-6, and IL-10) depending on the immune response. CLINICAL RELEVANCE: CAP may trigger a systemic inflammatory response and affect the aorta of patients.

Expression of Interleukin-1ß and Matrix Metalloproteinase-8 in Cytolytic and Noncytolytic Enterococcus faecalis-induced Persistent Apical Periodontitis: A Comparative Study in the Rat.

INTRODUCTION: Cytolytic Enterococcus faecalis possesses a highly toxic and proinflammatory capacity. Cytokines and proteases play important roles in the host inflammatory response. The aim of this study was to compare the local expression of interleukin (IL)-1ß and matrix metalloproteinase-8 (MMP-8) between persistent apical periodontitis (AP) infected by cytolytic and noncytolytic E. faecalis. METHODS: Eighty-four left upper first rat molars were divided into 4 groups: chronic AP group (n = 6), disinfection group (n = 6), cytolytic E. faecalis-infected persistent AP group (n = 36), and noncytolytic E. faecalis-infected persistent AP group (n = 36). Periradicular lesions were established after pulp exposure. After 3 weeks, root canals were prepared, and disinfected. E. faecalis strains ATCC 29212 or ATCC 700802 suspensions were inoculated into root canals 2 weeks later. Six samples were collected at different time points (1, 2, 3, 4, 5, and 6 weeks). The expression levels of IL-1ß and MMP-8 were detected by immunohistochemical staining. RESULTS: IL-1ß and MMP-8 expression trends in the cytolytic groups were similar to those of the noncytolytic group although at different time points the expression levels in the cytolytic group were significantly higher than those in the noncytolytic group (P < .01). IL-1ß expression enhancement occurred during the early phase of infection, whereas increased MMP-8 expression lasted for a prolonged period. CONCLUSIONS: Both E. faecalis strains could induce local IL-1ß and MMP-8 expression in persistent AP. Compared with noncytolytic E. faecalis, cytolytic E. faecalis may cause more severe local inflammation and tissue destruction in persistent AP.

Minimizing Concentration of Sodium Hypochlorite in Root Canal Irrigation by Combination of Ultrasonic Irrigation with Photodynamic Treatment.

Concentration of sodium hypochlorite (NaOCl) is positively correlated with its effectiveness in root canal disinfection but negatively correlated with its biocompatibility. The objective of this in vitro study was to compare the bactericidal effects among ultrasonic irrigation with different concentration of NaOCl alone or together with photodynamic treatment (PDT) against Enterococcus faecalis (E. faecalis) in infected root canals. One hundred and twenty bovine root canals contaminated with E. faecalis were randomly distributed into 12 groups treated with different disinfection methods: PDT, ultrasonic irrigation with NaOCl at different concentrations (0.5%, 1.0%, 2.0%, 2.5% and 5.25%), and ultrasonic irrigation with NaOCl at different concentrations plus PDT. Data of microorganism load were collected before and after disinfection and analyzed by one-way ANOVA and LSD tests. Significantly enhanced antibacterial effects were noticed in groups treated by PDT plus 2.0% or 2.5% NaOCl irrigation (P < 0.05). No statistical differences existed in bactericidal efficacy among groups of PDT plus ultrasonic irrigation with 2.0%, 2.5% or 5.25% NaOCl, and ultrasonic irrigation with 5.25% NaOCl alone (P > 0.05). Our study confirmed the feasibility to reduce the concentration of NaOCl to a safer level while maintaining its antibacterial efficiency through synergistic effect of PDT with NaOCl ultrasonic irrigation.