Octenidine in root canal and dentine disinfection ex vivo

AIM: The aim of the present study was to investigate the antimicrobial activity of octenidine on Enterococcus faecalis ATCC 29212 in a dentine block model. METHODOLOGY: Fifty-six root segments of extracted human teeth were infected with E. faecalis for 4 weeks. Octenidine-phenoxyethanol gel (1 : 1) was applied for different timing: 1 min, 10 min, 7 days and in a different formula (1 : 3) for 10 min. Three samples were chosen for the group with placebo gel and for the group without infection (negative control). Dentine samples were collected, and the total count of bacteria and colony-forming units were determined. In addition, for controls and the 10 min group with 1 : 1 gel, the proportion of viable bacteria (PVB) was assessed. RESULTS: Octenidine was particularly effective after incubation periods of 10 min and 7 days. The mean PVB decreased significantly from 57.2% to 5.7% after 10 min application. After 7 days, only one of 10 samples showed positive culture. CONCLUSION: The present study showed the effectiveness of octenidine against E. faecalis in dentine disinfection. Further laboratory and clinical studies are required.     

Endodontic photodynamic therapy ex vivo

Introduction

The objective of this study was to evaluate the antimicrobial effects of photodynamic therapy (PDT) on infected human teeth ex vivo.

Methods

Fifty-two freshly extracted teeth with pulpal necrosis and associated periradicular radiolucencies were obtained from 34 subjects. Twenty-six teeth with 49 canals received chemomechanical debridement (CMD) with 6% NaOCl, and 26 teeth with 52 canals received CMD plus PDT. For PDT, root canal systems were incubated with methylene blue (MB) at concentration of 50 μg/mL for 5 minutes, followed by exposure to red light at 665 nm with an energy fluence of 30 J/cm². The contents of root canals were sampled by flushing the canals at baseline and after CMD alone or CMD+PDT and were serially diluted and cultured on blood agar. Survival fractions were calculated by counting colony-forming units (CFUs). Partial characterization of root canal species at baseline and after CMD alone or CMD+PDT was performed by using DNA probes to a panel of 39 endodontic species in the checkerboard assay.

Results

The Mantel-Haenszel χ² test for treatment effects demonstrated the better performance of CMD+PDT over CMD (P = .026). CMD+PDT significantly reduced the frequency of positive canals relative to CMD alone (P = .0003). After CMD+PDT, 45 of 52 canals (86.5%) had no CFUs as compared with 24 of 49 canals (49%) treated with CMD (canal flush samples). The CFU reductions were similar when teeth or canals were treated as independent entities. Post-treatment detection levels for all species were markedly lower for canals treated by CMD+PDT than they were for those treated by CMD alone. Bacterial species within dentinal tubules were detected in 17 of 22 (77.3%) and 15 of 29 (51.7%) canals in the CMD and CMD+PDT groups, respectively (P = .034).

Conclusions

Data indicate that PDT significantly reduces residual bacteria within the root canal system, and that PDT, if further enhanced by technical improvements, holds substantial promise as an adjunct to CMD.     

The effect of sodium hypochlorite concentration and irrigation needle extension on biofilm removal from a simulated root canal model

To investigate the effect of sodium hypochlorite concentration and needle extension on removal of Enterococcus faecalis biofilm, sixty root canal models were 3D printed. Biofilms were grown on the apical 3 mm of the canal for 10 days. Irrigation for 60s with 9 mL of either 5.25% or 2.5% NaOCl or water was performed using a needle inserted either 3 or 2 mm from the canal terminus and imaged using fluorescence microscopy and residual biofilm percentages were calculated using imaging software. The data were analysed using analysis of covariance and two‐sample t‐tests. A significance level of 0.05 was used throughout. Residual biofilm was less using 5.25% than with 2.5% NaOCl. Statistically significant biofilm removal was evident with the needle placed closer to the canal terminus. A greater reduction of available chlorine and pH was noted as the concentration increased. One‐minute irrigation was not sufficient for complete biofilm removal.     

Evaluation of photodynamic therapy using a light-emitting diode lamp against Enterococcus faecalis in extracted human teeth

Introduction

Photodynamic therapy (PDT) with high-power lasers as the light source has been proven to be effective in disinfecting root canals. The aim of this study was to evaluate the antimicrobial effect of PDT using toluidine blue O (TBO) and a low-energy light-emitting diode (LED) lamp after the conventional disinfection protocol of 6% NaOCl.

Methods

Single-rooted extracted teeth were cleaned, shaped, and sealed at the apex before incubation with Enterococcus faecalis for 2 weeks. Roots were randomly assigned to five experimental groups and three control groups. Dentin shavings were collected from the root canals of all groups with a #50/.06 rotary file, colony-forming units were determined, and the bacterial survival rate was calculated for each treatment.

Results

The bacterial survival rate of the NaOCl/TBO/light group (0.1%) was significantly lower (P < .005) than the NaOCl (0.66%) and TBO/light groups (2.9%).

Conclusions

PDT using TBO and a LED lamp has the potential to be used as an adjunctive antimicrobial procedure in conventional endodontic therapy.     

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根管冲洗对根管的消毒和清理起着重要作用,冲洗液可以通过冲洗碎屑、溶解组织和消毒根管系统而提高机械预备的效力。次氯酸钠（NaClO）是目前世界范围内临床上使用最广泛的根管冲洗液之一。本文就NaClO的作用及相应机制、提高使用效率的方法、不良反应、与其他冲洗液联合应用等方面做一综述。     

Photodynamic therapy: An adjunct to conventional root canal disinfection strategies

Although chemical‐based root canal disinfectants are important to reduce microbial loads and remove infected smear layer from root dentin, they have only a limited ability to eliminate biofilm bacteria, especially from root complexities. This paper explores the novel photodynamic therapy (PDT) for antimicrobial disinfection of root canals. The combination of an effective photosensitizer, the appropriate wavelength of light and ambient oxygen is the key factor in PDT. PDT uses a specific wavelength of light to activate a non‐toxic dye (photosensitizer), leading to the formation of reactive oxygen species. These reactive oxygen molecules can damage bacterial proteins, membrane lipids and nucleic acids, which promote bacterial cell death. In, addition PDT may enhance cross‐linking of collagen fibrils in the dentin matrix and thereby improving dentin stability. The concept of PDT is plausible and could foster new therapy concepts for endodontics. The available knowledge should enable and encourage steps forward into more clinical‐oriented research and development. This article discusses PDT as related to root canal disinfection, including its components, mechanism of action, reviews the current endodontic literature and also highlights the shortcomings and advancements in PDT techniques.     

Effectiveness of calcium and sodium hypochlorite in association with reciprocating instrumentation on decontamination of root canals infected with Enterococcus faecalis

The aim of this study was to evaluate the antimicrobial activity of sodium and calcium hypochlorite utilising reciprocating instrumentation. Sixty root canals were inoculated with E. faecalis for 14 days. Samples were divided into six groups according to decontamination protocol: G1: no treatment, G2: distilled water, G3: 2.5% sodium hypochlorite, G4: 2.5% calcium hypochlorite, G5: 5.25% sodium hypochlorite and G6: 5.25% calcium hypochlorite. Instrumentation was performed with Wave One reciprocating system (Dentsply Sirona Endodontics, York, PA, USA) in groups G2 to G6. Colony‐forming units (CFUs) counting was performed and the data were subjected to Anova and Tukey (α  =  0.05). Group 1 and 2 showed the highest mean contamination, with a significant difference between them (P < 0.05). Groups 3, 4, 5 and 6 showed the lowest contamination means with no significant difference between them (P < 0.05). Sodium and calcium hypochlorite, in association with reciprocating instrumentation, can be an effective decontamination protocol in root canals infected with E. faecalis.     

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牙髓根尖周病是一类主要因细菌感染引起的、发生于牙髓及根尖周围组织的炎症性疾病,发病率高,是口腔常见病、多发病,占口腔内科门诊的60%,也是导致牙痛、失牙的主要原因.     

Antimicrobial efficacy of clindamycin and triple antibiotic paste as root canal medicaments on tubular infection: An in vitro study

This study compared the antibacterial effect of 2% clindamycin and 2% and 100% concentration of triple antibiotic paste (TAP) on an Enterococcus faecalis biofilm. Dentinal tubules of 100 root specimens were infected and randomly assigned to five groups. A total of 1000 mg mL^?1 of TAP, 20 mg mL^?1 of TAP and clindamycin, calcium hydroxide or methylcellulose (control) were placed in the root canal for 1 week. After treatment, dentine shavings were collected from 200 and 400 μm dentine depth and the number of colony‐forming units (CFU) per mg was determined. Reduction in viable bacteria in first three groups was significantly better than calcium hydroxide and control groups. However, the antimicrobial effectiveness among these three groups was not significantly different from each other. There was no significant difference between data at 200 and 400 μm in all groups except the Ca(OH)₂ group. The antibiofilm effect of clindamycin was comparable with TAP, so it may be used instead of TAP.     

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目的探讨前牙钙化根管治疗的可行性。方法2003年1月至2005年12月,对郑州市中医院口腔科收集的前牙钙化根管患者22例,通过寻找根管口,行根管治疗术,进行术前、术后X线片观察研究。结果20例患者顺利完成根管治疗术,2例因根管完全钙化行根尖手术。结论前牙钙化根管的治疗关键在于根管口的寻找,并进行常规根管治疗术,避免根尖手术或牙拔除术。     

Inability of laser and rotary instrumentation to eliminate root canal infection

BACKGROUND: The authors evaluated the antibacterial effectiveness of laser instrumentation and rotary instrumentation of anterior, single-rooted teeth infected with Enterococcus faecalis. METHODS: The authors divided 35 infected samples into five groups: Group A: inoculation, laser, 17 percent ethylene-diamine-tetra-acetate (EDTA), 2.5 percent sodium hypochlorite (NaOCl) (n=10); Group B: inoculation, laser, 17 percent EDTA, sterile saline (n = 10); Group C: inoculation, rotary, 17 percent EDTA, 2.5 percent NaOCl (n=10); Group D: inoculation, no instrumentation (positive control) (n=5); Group E: no inoculation, no instrumentation (negative control) (n=5). They sampled and incubated dentin shavings from each canal for bacterial growth. RESULTS: In Group A, eight tubes were positive for bacterial growth. In Group B, 10 tubes were positive for bacterial growth. In Group C, six tube were positive for bacterial growth. In Group D, all of the tubes were positive for bacterial growth. In Group E, no tubes showed bacterial growth. The Fisher exact test showed no significant differences among groups A, E and C. CONCLUSION: Neither the laser nor the rotary instrumentation was able to eliminate endodontic infection. CLINICAL IMPLICATIONS: Although lasers have been presented as high-tech tools for disinfecting root canals, the laser was ineffective in this study.