Aetiology of root canal treatment failure: why well-treated teeth can fail

The use of host defense peptides in root canal therapy in rats

OBJECTIVES

In order to evaluate host defense peptides (HDPs) HHC-10 and synoeca-MP activity in in vitro osteoclastogenesis process and in vivo induced apical periodontitis, testing the effect of molecules in the inflammatory response and in apical periodontitis size/volume after root canal treatment.

MATERIALS AND METHODS

In vitro osteoclastogenesis was assessed on bone marrow cell cultures extracted from mice, while in vivo endodontic treatment involved rats treated with Ca(OH)₂ or HDPs. In vitro osteoclasts were subjected to TRAP staining, and in vivo samples were evaluated by radiographic and tomographic exams, as well as histologic analysis.

RESULTS

None of the substances downregulated the in vitro osteoclastogenesis. Nevertheless, all treatments affected the average of apical periodontitis size in rats, although only teeth treated with HDPs demonstrated lower levels of the inflammatory process. These results demonstrated the in vivo potential of HDPs. Radiographic analysis suggested that HHC-10 and synoeca-MP-treated animals presented a similar lesion size than Ca(OH)₂-treated animals after 7-day of endodontic treatment. However, tomography analysis demonstrated smaller lesion volume in synoeca-MP-treated animals than HHC-10 and Ca(OH)₂-treated animals, after 7 days.

CONCLUSIONS

These molecules demonstrated an auxiliary effect in endodontic treatment that might be related to its immunomodulatory ability, broad-spectrum antimicrobial activity, and possible induction of tissue repair at low concentrations. These results can encourage further investigations on the specific mechanisms of action in animal models to clarify the commercial applicability of these biomolecules for endodontic treatment.

CLINICAL SIGNIFICANCE

HDPs have the potential to be adjuvant substances in endodontic therapy due to its potential to reduce inflammation in apical periodontitis.

Proteomic analysis of human dental pulp in different clinical diagnosis

OBJECTIVES

The present study aimed to identify proteins obtained from pulp tissue and correlate with each clinical diagnosis (healthy pulp, inflamed pulp, and necrotic pulp).

MATERIALS AND METHODS

A total of forty-five molars were used. Three biological replicas were evaluated. Lysis and sonication were used for protein extraction. Protein quantification was assessed by using the Bradford technique, and shotgun proteome analysis was performed by nanoUPLC-MS^E using a Synapt G2 mass spectrometer. Mass spectra data were processed using the Waters PLGS software, and protein identification was done using the human Uniprot database appended to the PLGS search engine.

RESULTS

A total of 123 different proteins were identified in all evaluated pulp conditions. Among these, 66 proteins were observed for healthy pulp, 66 for inflamed pulp, and 91 for necrotic pulp. Most protein identification was related to immune response, multi-organism process, platelet activation, and stress in inflamed pulp samples compared to healthy pulp. Proteins related to cellular component organization or biogenesis, developmental process, growth, immune response, multi-organism process, response to stimulus, signaling, stress, and transport were identified in cases of apical periodontitis compared to inflamed pulp.

CONCLUSIONS

The progression of the disease to inflamed pulp promoted a high abundance of proteins related to the immune system and stress. Comparing the necrotic pulp with inflamed pulp conditions, a high abundance of proteins was noticed related to metabolism, transport, and response between organisms.

CLINICAL RELEVANCE

This finding may assist in future studies of new markers, understanding of tissue engineering, and development of future products.

Antimicrobial activity and inhibition of biofilm formation in vitro and on human dentine by silver nanoparticles/carboxymethyl-cellulose composites

OBJECTIVE

To evaluate the antimicrobial activity of a silver nanoparticles/carboxymethyl-cellulose (AgNPs/CMC) composite on in vitro and dentine disc heterogeneous biofilms.

DESIGN

AgNPs/CMC composite effect on normal human gingival fibroblast cells (HGF) viability was determined by the MTT reduction assay. In addition, we evaluated the antimicrobial effect of AgNPs/CMC composite on Candida albicans, Enterococcus faecalis, and Fusobacterium nucleatum growth in vitro and heterogeneous biofilms, as well as dentine disc biofilms.

RESULTS

Quasi-spherical AgNPs/CMC composites, with a mean 22.3 nm particle-size were synthesized. They were not toxic to HGF cells at concentrations tested that were antimicrobial, however they caused significant cytotoxicity (89 %, p <  0.05) at concentrations > 15 μg/mL. In vitro, they inhibited up to 67 %, 66 %, and 96 % C. albicans, E. faecalis, and F. nucleatum growth at concentrations ranging from 1.2 μg/mL to 9.6 μg/mL, as compared with untreated control. We also demonstrated significant (p <  0.05) 58 % biofilm reduction by 4.8 μg/mL AgNPs/CMC composite on human dentine discs.

CONCLUSION

AgNPs/CMC composite showed anti biofilm activity on monocultures, heterogenous cultures, and dentine discs, resulting a potentially effective alternative to prevent and eliminate infections after endodontic treatment.

Dentin-Pulp Tissue Regeneration Approaches in Dentistry: An Overview and Current Trends

Conventional treatment approaches in irreversible pulpitis and apical periodontitis include the disinfection of the pulp space followed by filling with various materials, which is commonly known as the root canal treatment. Disadvantages including the loss of tooth vitality and defense mechanism against carious lesions, susceptibility to fractures, discoloration and microleakage led to the development of regenerative therapies for the dentin pulp-complex. The goal of dentin-pulp tissue regeneration is to reestablish the physiological pulp function such as pulp sensibility, pulp repair capability by mineralization and pulp immunity. Recent dentin-pulp tissue regeneration approaches can be divided into cell homing and cell transplantation. Cell based approaches include a suitable scaffold for the delivery of potent stem cells with or without bioactive molecules into the root canal system while cell homing is based on the recruitment of host endogenous stem cells from the resident tissue including periapical region or dental pulp. This review discusses the recent treatment modalities in dentin-pulp tissue regeneration through tissue engineering and current challenges and trends in this field of research.

Evaluation of root and canal morphology of maxillary permanent first molars in an Emirati population; a cone-beam computed tomography study

Background

The aim of this study was to analyze the root and canal morphology of the maxillary permanent first molars in an Emirati population using cone-beam computed tomography (CBCT).

Methods

Two hundred and sixty-one CBCT scans were acquired. The data were extracted and anonymized to remove all patient identifiers. Two observers (an endodontic resident and an endodontist) evaluated all scans on diagnostic quality monitors.

Results

The prevalence of a second mesiobuccal canal (MB2) was 80.1% in all examined samples. Type II Vertucci classification, was the most common canal configuration (59%) in the mesiobuccal root, followed by Types I (19.9%) and IV (15.3%), while Type III was the least common (5.7%). Types I, II, and IV were significantly more common in the 21–40-year age group (P < 0.001), while Type III was observed significantly more often in the < 20-year age group (P < 0.001). No significant effect of gender on the prevalence of Vertucci classification in the mesiobuccal root of maxillary first molars (P = 0.74) was found. Analysis of bilateral symmetry showed that 80% teeth had perfect bilateral symmetry, whereas 20% were asymmetrical. Type II canal configuration showed the highest prevalence of bilateral symmetry (48.7%), followed by Type I (15%) and Type IV (10%), while Type III showed the least prevalence of symmetry (3%).

Conclusions

This was the first study to analyze the prevalence of MB2 canal in an Emirati population. Our results indicate high prevalence of MB2 (80.1%) and emphasize the importance of using advanced techniques to locate the MB2 canal.

Ethical Aspects concerning Instrument Separation and Perforations during Endodontic Treatment: A Cross-Sectional Study

Aim

During endodontic treatment, dentists may face various unwanted procedural accidents, at any stage of the treatment that might compromise endodontic treatment outcome and bring obstacles to dentists as well. This study aimed to address and analyze several ethical concerns relating to the behavioural conduct of dentists towards endodontic instrument separation as well as perforation of the crown and/or root during root canal treatment in Riyadh, Saudi Arabia.

Method

Hundred and eleven questionnaires were distributed among dentists working in Riyadh in university clinics and government and private sectors. Data were collected, reviewed, and statistically analyzed by Fisher's exact and chi-square tests at a 5% significance level, using SPSS software.

Results

54.5% of the respondents have encountered instrument separation. 53.2% stated that they would inform the patient about the instrument separation. 43.6% of the respondents had experienced perforation during root canal treatment, and 54.9% reported that they would inform the patient of the accident.

Conclusion

Within the limitation of this survey, we concluded that most of the dental professionals did not hesitate to adhere to the correct ethical conduct, and they would inform the patient if an incident occurred.

Cigarette Smoking and Root Filled Teeth Extraction: Systematic Review and Meta-Analysis

AIM

The aim of this systematic review and meta-analysis was to investigate the possible association between smoking habits and the occurrence of root-filled teeth (RFT) extraction.

MATERIAL AND METHODS

The Population, Intervention, Comparison, and Outcome (PICO) question was in adult patients who had RFT, does the absence or presence of smoking habits affect the prevalence of extracted RFT? Systematic MEDLINE/PubMed, Wiley Online Database, Web of Science, and PRISMA protocol was used to evaluate and present the results. The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system was used for certainty in the evidence. The risk of bias was assessed according to Cochrane Collaboration common scheme for bias and ROBINS-I tool. Cumulative meta-analysis was performed with a random effects model. PROSPERO registration code: CRD42020165279.

RESULTS

After search strategy, 571 articles were recovered, seven were selected for full-text analysis, and two reported data on inclusion criteria, including 516 RFT, 351 in non-smokers, and 165 in smoker subjects. The meta-analysis provided an odds ratio indicating significant association between smoking and the prevalence of extracted RFT (OR = 3.43, 95% CI = 1.17-10.05, p = 0.02, I² = 64%). The certainty of the literature assessment was low per GRADE. Both studies were considered as moderate risk of bias.

CONCLUSIONS

Tobacco smoking should be considered a negative prognostic factor for the outcome of root canal treatment, although the quality of the evidence is low. RFT of smoking patients are three times more likely to be extracted. Continuing to smoke after endodontic treatment may increase the risk of treatment failure. However, the overall strength of evidence is low. This must be considered a limitation of the present study and the conclusion should be valued with caution.

Mandibular first premolar with five root canals: a case report

Background

Understanding the anatomical morphology of the root canal is key for successful root canal treatment. The aims of this case presentation are to report a unique case of root canal treatment involving five root canals in the mandibular first premolar and to highlight the importance of variation in root canals of mandibular first premolars in clinical practice.

Case presentation

A 25-year-old male with intermittent pain in relation to the lower right posterior teeth over 3 weeks was diagnosed with symptomatic pulpitis in tooth #44. Four root canals were found, including mesiobuccal, distobuccal-1, distobuccal-2, and distolingual roots, and the Mtwo rotary system was used for root canal preparation. The four root canals were filled after 2 weeks, when a fifth canal was found, located in the buccal cavity. The fifth canal was confirmed to be the mesiolingual root canal by cone beam computed tomography (CBCT) and was found to be curved. After completion of the root canal filling, CBCT was performed, and a three-dimensional root canal image was reconstructed. After 1 week of observation, the tooth was repaired using composite resin filling.

Conclusions

This is the first case presentation of a fifth canal of the mandibular first premolar and advances our understanding of variations in the anatomy of the mandibular first premolar. This case report provides a reference for the treatment of mandibular first premolars.

Effect of duration and dilution on antimicrobial efficacy of octenidine hydrochloride as an intracanal medicament with chitosan carrier against Enterococcus faecalis - A modified direct contact test

BACKGROUND

The ambiguity in key influential factors such as minimal time for effective action, dilution, and need of drug carrier for intracanal medicaments necessitates a microbial analysis that aids in the potential selection of an intracanal medicament for ensuring optimal root canal disinfection.

AIMS

This study aims to evaluate the antimicrobial efficacy of octenidine hydrochloride (OHC) and gold standard calcium hydroxide (Ca(OH) 2) as intracanal medicaments, both independently and along with chitosan (CTS) as medicament vehicle against the common resistant endopathogen - Enterococcus faecalis.

MATERIALS AND METHODS

A modified direct contact microbial test was used to evaluate the amount of surviving bacteria after predetermined contact time (2, 5, 20, and 60 min) and 5-fold serial dilution of the intracanal medicaments. The experiment was carried out under aseptic conditions and performed in triplicate to ensure reproducibility.

STATISTICAL ANALYSIS USED

The results were analyzed by Kruskal-Wallis analysis of variance followed by pairwise comparisons by Mann-Whitney U-test.

RESULTS AND CONCLUSIONS

The results showed that all the four medicament groups were able to show the maximum antimicrobial efficacy against E. faecalis at 60 min time interval and that the antimicrobial efficacy of OHC and Ca(OH) 2 was at its peak when used alone. The study thereby concluded that the addition of CTS as a carrier did not enhance the antimicrobial efficacy of OHC or Ca(OH) 2 against E. faecalis.

Comparison of Antibacterial Effect of Calcium Hydroxide Combined With Chlorhexidine and Povidone-Iodine Against Enterococcus faecalis in Dentinal Tubules of Human Incisors: An In Vitro Comparative Study

Background and Objectives:

It has been found that the microorganism behind the failure of root-filled teeth is Enterococcus faecalis, which shows resistance to most of the intra-canal medicaments. Therefore, the purpose of this study was to evaluate the antibacterial efficacy of three intra-canal medications—calcium hydroxide with saline, combinations of calcium hydroxide with 2% chlorhexidine (CHX), and calcium hydroxide with 5% povidone-iodine—against E. faecalis in dentinal tubules of human incisors.

Materials and Methods:

Forty permanent maxillary central incisors were made into standardized segments and infected with E. faecalis. They were treated with a paste made of calcium hydroxide and 2% CHX, calcium hydroxide and 5% povidone-iodine, and calcium hydroxide and saline for 1 week. Dentinal shavings collected from the canal were suspended in thioglycollate broth solution and spread on brain heart infusion agar. Colony-forming units (CFUs) were enumerated and the CFU per milligram of dentin was calculated. The pH of the medicaments used was measured with the help of pH meter.

Results:

The results showed that the paste made from calcium hydroxide and 2% CHX was significantly more effective than that made from calcium hydroxide and povidone-iodine, and calcium hydroxide and saline. The addition of CHX or povidone-iodine did not affect the alkalinity of calcium hydroxide.

Conclusion:

This study concludes that Ca(OH)₂ + 2% CHX are effective against E. faecalis. Combinations of calcium hydroxide and 5% povidone-iodine showed better antibacterial effect than calcium hydroxide and saline. Ca(OH)₂ + saline was ineffective against E. faecalis.

Improving the Efficiency of Photodynamic Chemotherapy in Root Canals against Enterococcus faecalis In Vitro

The aim of this study was to evaluate the effect of photoactivated chemotherapy (PACT) on Enterococcus faecalis (E. faecalis) biofilms in root canals using an 90% isopropanol (IPA)-based photosensitizer and removing excess photosensitizer before light incubation. Three hundred and seven extracted human teeth with one root canal were infected with E. faecalis for 72 h and treated in groups: IPA irrigation; PACT; PACT and final rinse with IPA; PACT with photosensitizer removal using either 0.9% NaCl solution or sterile paper points or both; PACT using IPA-based photosensitizer with and without a final rinse of IPA. Root canals were sampled using sterile paper points and dentin chips collected from the root canal walls. Additionally, SEM (Scanning Electron Microscopy) images of the specimens were taken to evaluate the root canal walls for residue bacterial contamination. In all antimicrobial treatment groups treatments E. faecalis counts were significantly reduced in the root canals. Using IPA-based photosensitizer the antimicrobial effect of PACT was significantly enhanced. Irrigation with IPA alone or after PACT significantly increased the antimicrobial effect compared to PACT alone. The collected dentin chips revealed the highest amount of culture negative root canals (10%) after PACT using IPA-based photosensitizer. In the other groups, the culture negative samples ranged from only 0–2 specimens of 30 specimens. REM images show remaining E. faecalis cells on the root canal wall and inside dentin tubules. Using IPA-based photosensitizer significantly enhanced the antimicrobial effect of PACT against E. faecalis in the root canals.

Comparison of dentin penetration ability of different root canal sealers used with different obturation methods

This in vitro study aimed to investigate the tubular penetration depth of four different sealers used with two different obturation methods in the apical, middle, and coronal root canal dentin. Eighty-four single-rooted teeth were instrumented until the F4 ProTaper universal rotary file and filled with AH26, AH Plus (Dentsply, DeTrey, Konstanz, Germany), RealSeal (SybronEndo, Orange, CA), and MTA Fillapex (Angelus, Londrina, Brazil) using cold lateral condensation (CLC) and single-cone (SC) obturation techniques. Thereafter, the roots were sectioned longitudinal and prepared for scanning electron microscope evaluation. The maximum and minimum sealers penetration depth into dentinal tubules at the apical, middle, and coronal regions and the average depth of sealer penetration were calculated. The data was statistically analyzed two-way ANOVA and post hoc Tukey and Dunnett tests and independent samples t test using maximum mean values. There was no statistically difference between the obturation methods (p > .05). When the sealers are evaluated within themselves AH26 was affected by obturation methods significantly (p < .05). Also the results revealed a significant difference between root regions (p < .05). AH26 and RealSeal root canal sealers had the highest penetration values with CLC and SC obturation techniques, respectively. The obturation method did not affect the penetration amount of root canal sealers. RealSeal root canal sealer performed better penetration ability than the other sealers. Apical third of the root in all groups showed lowest penetration depth.

Microbial Association with Genus Actinomyces in Primary and Secondary Endodontic Lesions, Review

The main reason for root canal treatment failure is the persistence of microorganisms after therapy, or the recontamination of the root canal system due to an inadequate seal. In the mouth, Actinomyces spp. constitute a significant part of the normal flora, which is indicative of their ability to adhere to oral tissue and resist cleansing mechanisms, such as salivary flow. This review, performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA), aims to clarify the prevalence of microbial genera that are associated with the genus Actinomyces in primary and secondary endodontic infections (primary outcome), and to identify the most prevalent species of the Actinomyces genus in endodontic lesions (secondary outcome). A total of 11 studies were included in the qualitative and quantitative analysis, and a total of 331 samples were analyzed. Bacteria of the genus Actinomyces were found in 58 samples, and 46 bacterial genera were detected in association with bacteria of the genus Actinomyces. Bacteria of the genus Streptococcus and Propionibacterium were those most frequently associated with Actinomyces in the endodontic lesions considered, and Actinomyces israelii was the most frequently involved species.

Endodontic Periapical Lesion: An Overview on the Etiology, Diagnosis and Current Treatment Modalities

Nonsurgical and surgical endodontic treatments have a high success rate in the treatment and prevention of apical periodontitis when carried out according to standard and accepted clinical principles. Nevertheless, endodontic periapical lesions remain in some cases, and further treatment should be considered when apical periodontitis persists. Although several treatment modalities have been proposed for endodontically treated teeth with persistent apical periodontitis, there is a need for less invasive methods with more predictable outcomes. The advantages and shortcomings of existing approaches for the diagnosis and treatment of endodontic periradicular lesions are discussed in this review.

Rapid Chairside Microbial Detection Predicts Endodontic Treatment Outcome

Background. The aim of this longitudinal, one-year cohort study was to explore the hypothesis that fluorescence sampling of the root canal space prior to obturation could predict the outcome of root canal treatment (RCT). Methods. Sixty-five teeth underwent primary RCT and were followed up clinically and radiographically. The outcome was determined radiographically with periapical radiographs (PR) and cone beam computed tomography (CBCT) scans. Results. Success at 12 months was predictable based on the fluorescence score. When the fluorescence score (defined as the percentage of signal over total signal including background) was lower than 67, there was a 4.5 times (Odds ratio (OR) = 0.028; 95% confidence interval (CI): 0.003, 0.291, p = 0.001) greater chance of success (90% overall). When the readings were above this threshold, the success rate was 20%. Conclusion. A chairside sampling method is able to predict the outcome of RCT, through the use of paper point sampling and fluorescence staining. This has reduced the prevalence of persistent infections by guiding the optimum time for obturation. ClinicalTrials.gov trial NCT03660163.

The Efficacy of Rotary, Reciprocating, and Combined Non-Surgical Endodontic Retreatment Techniques in Removing a Carrier-Based Root Canal Filling Material from Straight Root Canal Systems: A Micro-Computed Tomography Analysis

The aim of this study is to analyze and compare the efficacy of three non-surgical endodontic retreatment techniques in removing a carrier-based root canal filling material from straight root canal systems. The study was performed on 99 single-rooted extracted teeth using the ProTaper Gold endodontic rotary system up to the F2 file (Dentsply Maillefer, Baillagues, Switzerland), which were sealed with GuttaCore (Dentsply Maillefer, Ballaigues, Switzerland) and AH plus epoxy resin sealer (Dentsply DeTrey, Konstanz, Germany) and randomly assigned to the following non-surgical retreatment techniques: ProTaper Retreatment endodontic rotary instruments (D1–D3 files, Dentsply Maillefer, Ballaigues, Switzerland; n = 33, PTR), Reciproc Blue endodontic reciprocating instrument (R50, VDW, Munich, Germany; n = 33, RCB50), and a combined root canal retreatment technique between Gates-Glidden drills (sizes #3 and #2, Dentsply Maillefer, Ballaigues, Switzerland) and Hedstrom files (file size 35, 30, and 25, Dentsply Maillefer, Ballaigues, Switzerland; n = 33; H-GG). All of the teeth were submitted twice to a micro-computed tomography (micro-CT) scan, before and after non-surgical endodontic retreatment procedures. The volume of root canal filling material (mm³), volume of remaining root canal filling material (mm³), non-surgical endodontic retreatment working time (min), proportion of remaining root canal filling material (%), and efficacy of root canal filling material removal between the non-surgical endodontic retreatment techniques were analyzed using ANOVA one-way statistical analysis. Statistically significant differences were observed between the proportions of remaining root canal filling material of PTR and H-GG (p = 0.018), between the non-surgical endodontic retreatment working times (min; p < 0.001), and between the efficacies of root canal filling material removal by the non-surgical endodontic retreatment techniques (p = 0.009). However, the non-surgical endodontic retreatment systems allow for similar carrier-based root canal filling material removal.

Effect of sodium hypochlorite solution and gel with/without passive ultrasonic irrigation on Enterococcus faecalis, Escherichia coli and their endotoxins

Background: Sodium hypochlorite (NaOCl) is the most commonly used irrigant in endodontics . The purpose of this study was to evaluate the effect of NaOCl solution (2.5%) and gel (3%) with/without passive ultrasonic irrigation (PUI) on Enterococcus faecalis, Escherichia coli, and their endotoxins, lipopolysaccharide (LPS) and lipoteichoic acid (LTA).

Methods: 40 human lower premolars were contaminated with E. coli (ATCC 25922) for 28 days and E. faecalis (ATCC 29212) for 21 days. Specimens were randomly divided into four groups: (1) 2.5% NaOCl irrigating the canals without PUI activation; (2) 2.5% NaOCl with PUI; (3) 3% NaOCl gel irrigating the canals without PUI; and (4) 3% NaOCl gel with PUI. 40 mL of irrigant was used for each group. PUI activation was carried out using E1-Irrisonic stainless-steel tip at 10% frequency. After treatment, all specimens were filled with 3mL of 17% ethylenediaminetetraacetic acid (EDTA) for 3min and then washed with nonpyrogenic saline solution. Three samples were collected from the canals: S1, at baseline to confirm biofilm formation; S2 after treatment; and S3 after EDTA. Samples were assessed for E. coli and E. faecalis colony forming units, and LPS and LTA were assessed using chromogenic kinetic LAL assay and ELISA, respectively. Data were analyzed by Kruskal-Wallis, Friedmann and Dunn tests with α≤0.05.

Results: All groups were effective in reducing the microbial load of E. coli and E. faecalis after treatment without a significant difference among the groups. NaOCl and NaOCl gel groups had no significant difference in reducing LPS and LTA. Statistically increased reduction was seen for NaOCL + PUI and NaOCl gel + PUI compared for groups without PUI.

Conclusions: NaOCl gel has the same antimicrobial action of NaOCl solution and can partially detoxify endotoxins. PUI improves NaOCl (gel or solution) action over E. faecalis and E. coli and their endotoxins.

Retrograde Instrumentation of Surgically Resected Roots Using Controlled Memory Files: A Human Cadaver Study

INTRODUCTION

The purpose of this study is to evaluate the amount of residual obturation material of retroinstrumented surgically resected roots using controlled memory files and to evaluate the incidence of adverse treatment outcomes.

METHODS

Thirty maxillary anterior teeth in human cadavers were selected, and nonsurgical root canal treatment was performed on these teeth. A standardized 4-mm osteotomy and a 3-mm root resection with as close to 0° bevel as possible were made on each tooth. A microsurgical diamond tip was used to create a 1- to 2-mm starting point for each retropreparation. A 25/06 and 30/06 VTaper 2H were bent at about 90° angle to mimic the clinical and anatomic restrictions and used to create a retropreparation to a depth of 14 mm. Micro-computed tomography scans were taken and analyzed for volume and percentage of residual obturation material at 5 and 10 mm. In addition, the incidences of instrument separation and crack and ledge formation in the teeth were recorded.

RESULTS

The median volume of residual obturation at 5 and 10 mm was 0.18 mm³ (interquartile range, 0.36 mm³) and 1.97 mm³ (interquartile range, 1.99 mm³), respectively. The overall incidence of file separation during retropreparation was 13.33% (4/30). Among the cases analyzed with micro-computed tomography, none showed crack or ledge formation.

CONCLUSIONS

Retroinstrumentation of surgically resected roots using controlled memory files cleans the canal effectively with relatively low adverse treatment outcomes. Although this novel technique is limited in application, it is a safe and effective way to achieve a deep, clean retropreparation.

Evaluation of Passive Ultrasonic Irrigation and GentleWave System as Adjuvants in Endodontic Retreatment

INTRODUCTION

Nonsurgical endodontic retreatment continues to be a challenge in endodontics, particularly when dealing with a complex tooth anatomy. This study evaluated the efficacy of passive ultrasonic irrigation (PUI) and the GentleWave system as supplementary techniques to remove remaining filling materials from oval-shaped root canals.

METHODS

Twenty distal roots of human mandibular molars with single and oval-shaped canals were shaped with R40 (40.06) instrument and filled with gutta-percha and AH Plus sealer using warm vertical obturation. Initial filling material removal was performed with R50 (50.05) instrument, followed by the use of PUI (n = 10) or GentleWave system (n = 10). Micro-computed tomographic images were obtained after obturation, initial material removal, and after the use of PUI and GentleWave. The volume of remaining filling material was calculated for the entire canal as well as for the coronal, middle, and apical thirds. Statistical analyses were performed by using analysis of variance, Kruskal-Wallis and Mann-Whitney tests. P ≤ .05 was considered significant.

RESULTS

The use of PUI and GentleWave as supplementary techniques significantly reduced the volume of remaining filling material after initial instrumentation (P < .05). However, none of these techniques was able to render canals free from filling materials. PUI showed better performance by removing 18% of the remaining filling material, whereas the GentleWave system was able to remove approximately 10% (P = .02).

CONCLUSIONS

The use of supplementary techniques optimized filling material removal after initial instrumentation. PUI enhanced the overall cleaning of the root canal system during endodontic retreatment in oval-shaped canals.

Prevalence and morphology of multiple roots, root canals and C-shaped canals in mandibular premolars from cone-beam computed tomography images in a Thai population

Background/purpose

Variations in root and root canal morphology of mandibular premolars of Thais has not been reported, and understanding these variations enhances endodontic success. The purpose was to investigate prevalence and morphology of multiple roots, root canals and C-shaped canals in mandibular premolars in a Thai population from cone-bean computed tomography (CBCT) images.

Materials and methods

A total of 349 first mandibular premolars and 416 second premolars from CBCT images with 0.125-mm voxel size and 60 × 60 mm field of view were evaluated. Number of roots, root canals, and C-shaped canals were recorded and statistically analyzed using chi-square test. Root canal configurations were defined according to the Vertucci's classification. Levels and distances of separated multiple canals were reported.

Results

Multiple roots in mandibular first premolars were found at 5.73% while none of second premolars had. Multiple root canals were found in the first premolars at 19.48% and the second premolars at 3.85%. C-shaped canals (C1/C2) were found in the first premolars at 3.72% and the second premolars at 0.48%. All parameters in the first premolars were significantly higher than in the second premolars (p < 0.01). The majority of multiple root canals were defined as Vertucci's type V (1–2 canals). Multiple root canals were frequently separated at the middle level of roots about 6.5–7.0 mm from the cementoenamel junction.

Conclusion

Prevalence of multiple roots/root canals and C-shaped canals in mandibular first premolars were significantly higher than in mandibular second premolars. Level of separation in multiple root canals was frequently at the mid-root level.

Antimicrobial Activity of Nano-Magnesium Hydroxide Against Oral Bacteria and Application in Root Canal Sealer

BACKGROUND The goal of the present work was to assess the antibacterial activity of nano-magnesium hydroxide (NMH) against Streptococcus mutans (S. mutans) and to explore the antimicrobial function of AH Plus™ sealer incorporating NMH. MATERIAL AND METHODS The antimicrobial behavior of NMH against S. mutans was evaluated with bactericidal tests. A modified direct contact test was used to assess the antimicrobial activity of unset AH Plus containing NMH after 5 minutes, 20 minutes, and 60 minutes of contact with bacteria. The antimicrobial effects and the amount of surface-adhering bacteria of the solidified materials were explored by SEM and confocal laser scanning microscopy, respectively. RESULTS NMH powder presented excellent antimicrobial activity against S. mutans. Mg²⁺ and OH⁻ were not the main factors resulting in bacterial death. Approximately 93.1% and 98% of the S. mutans were killed in the AH Plus+7% NMH group after incubation for 5 minutes and 20 minutes, respectively. AH Plus with 5% or 7% NMH were more potent against S. mutans compared with AH Plus alone (P<0.05). Moreover, the antibacterial function of AH Plus was lost after setting. NMH enabled the solidified AH Plus to still have antibacterial properties on the seventh day. CONCLUSIONS NMH can be used to modify AH Plus sealer to eradicate residual bacteria and prevent reinfection.

A long-term treatment outcome of intentional replantation in Taiwanese population

BACKGROUND/PURPOSE

Intentional replantation was a conventional treatment option in surgical endodontics but usually be seen as a last resort. Therefore, the purpose of this study was to evaluate the long-term treatment outcome of intentional replantation in Taiwanese population, including the survival rates and the related prognostic factors.

METHODS

Subjects included 215 teeth from 199 patients who had received intentional replantation in a Taiwan medical center. Patients at age under 20 years and those follow-up periods less than 6 months were excluded. The replanted teeth were followed up for a period of 6 months-120 months. Post-treatment assessments, including tooth survival and functional status, were evaluated using both clinical and radiographic examinations.

RESULTS

Kaplan-Meier survival analysis revealed the overall tooth survival rate at 4 years was 82.8%. In bivariate analysis, both root-end filling material and enamel matrix derivative (EMD) applications were found to be significant (P < 0.05). The multivariate analysis revealed that age and the presence of a sinus tract or abscess might be the predictors of treatment outcome in intentional replantation.

CONCLUSION

Intentional replantation, operated with improved modern technique, is a reliable and viable treatment with a high long-term survival rate (82.8%). If replanted teeth are diagnosed as acute or chronic apical abscess at the pre-operative examination, the risk of failure is measured 2.7 times higher than those diagnosed with other conditions. Application of EMD on the root surface of a replanted tooth may promote the formation and regeneration of periodontal apparatus, therefore increasing the functioning rate and improving the treatment outcome.

An Unusual Case of a Large Periapical Cyst Mimicking a Nasopalatine Duct Cyst

This article reports on the management of a large median symmetrical lesion of the anterior palate, which was clinically and radiographically diagnosed as an infected nasopalatine duct cyst. However, histopathology demonstrated it to be a radicular cyst of endodontic origin.

In Vivo Evaluation of Painful Symptomatology after Endodontic Treatment Performed Using Two Different Irrigation Needle Insertion Depths

Objective  The main purpose of this study was to evaluate pain symptoms in patients after endodontic treatment performed in a single session in teeth with vitality or pulp necrosis, comparing two depths of insertion of the NaviTip irrigation needle.

Materials and Methods  One-hundred upper uniradicular teeth were selected and divided into four groups ( n = 25), namely Bio group 1 (live pulp/1 mm from the foramen), Bio group 3 (live pulp/3 mm from the foramen), Necro group 1 (pulp necrosis/1 mm from the foramen), and Necro group 3 (pulp necrosis/3 mm from the foramen). All canals were instrumented with Wave One Gold System. Irrigation was performed using 2.5% NaOCl. The teeth were filled using the single-cone technique with AH Plus sealer using a McSpadden compactor. After treatment, patients answered a questionnaire with a visual analog scale scored from 0 to 10 at 1, 3, and 7 days after treatment.

Statistical Analysis  Data were analyzed using Mann–Whitney U, Wilcoxon, and Friedman tests.

Results  There was a decrease in average pain levels at the three time points for both vital and necrotic teeth ( p < 0.05). There were no significant differences in postoperative pain levels comparing needle depth, or vitality and pulp necrosis ( p > 0.05). The percentage of mild pain increased over time and moderate pain decreased, regardless of pulp condition. There was no incidence of acute pain at any time.

Conclusions  Post-treatment endodontic pain levels in upper uniradicular teeth with or without pulp vitality resulted in similar pain scores, regardless of the depth of insertion of the irrigation needle in relation to the apical foramen.

Evaluation of Photodynamic Therapy Using a Diode Laser 635 nm as an Adjunct to Conventional Chemo-Mechanical Endodontic Procedures against Enterococcus faecalis Biofilm: Ex-Vivo Study

The study aimed to evaluate the antimicrobial effect of photodynamic therapy (PDT) with the use of Toluidine Blue (TB) on extracted teeth infected with biofilms of Enterococcus faecalis. Fifty-four extracted teeth with single-roots and single canals were mechanically shaped, autoclaved, and contaminated with E. faecalis. They were randomly divided into six groups: two groups were negative and positive control groups, two groups were subjected to mechanical instrumentation and PDT with different pre-irradiation times and irradiation times, and two groups were subjected to chemo-mechanical endodontic treatment and PDT with different pre-irradiation times and irradiation times. In PDT groups, after the application of TB, the canals were irradiated with a diode laser of wavelength 635 nm, with a fiber diameter of 200 μm and 100 mW of power in continuous mode. The bacterial load was evaluated using a BioTimer Assay protocol. The greatest reduction of bacterial load was observed in groups of combined PDT with chemo-mechanical treatment. The reductions of bacterial load in groups of combined PDT with chemo-mechanical treatment, and in the positive control group, were significant (p < 0.01) when compared to that of the negative control group. Photodynamic therapy as an adjunctive modality may improve the disinfection capacity of conventional endodontic treatment against E. faecalis.

Prevalence of the Genus Propionibacterium in Primary and Persistent Endodontic Lesions: A Systematic Review

Propionibacterium are anaerobic/aero-tolerant rod Gram-positive bacteria, and numerous studies are associated with primary and secondary endodontic infections. The data in the literature on the prevalence of Propionibacterium are conflicting, and there are studies that report conflicting data on the prevalence in primary and secondary endodontic infections. This review aims to clarify the prevalence of bacteria of the genus Propionibacterium in endodontic lesions. The present systematic review work was performed on the basis of the Prisma protocol. A search was carried out on the PubMed and Scopus databases with the use of keywords. The research produced 410 records, which, after the elimination of the overlaps and the application of the inclusion and exclusion criteria, led to a number of 36 included articles divided by the three outcomes. The first outcome concerns prevalence of bacteria of the genus Propionibacterium in primary and secondary endodontic lesions. The secondary outcome, differences in the prevalence of bacteria of the genus Propionibacterium between primary endodontic infections and secondary endodontic infections. The tertiary outcome, differences in the prevalence of Propionibacterium Acnes compared to Propionibacterium propionicum in endodontic infections. The results of the meta-analysis show that the genus Propionibacterium bacteria are more prevalent in secondary endodontic infections and that P. Acnes has a higher prevalence than P. propionicum.

Vibrational and sonochemical characterization of ultrasonic endodontic activating devices for translation to clinical efficacy

Passive activation of endodontic irrigants provides improved canal disinfection, smear layer removal, and better subsequent sealing. Although evidence suggests that passive activating endodontic devices increase the effectiveness of irrigation, no study exists to quantitatively compare and validate vibrational characteristics and cavitation produced by different ultrasonic endodontic devices. The current study aims to compare the efficiency of various commercially available ultrasonic endodontic activating devices (i.e., EndoUltra™, EndoChuck, Irrisafe™, and PiezoFlow®). The passive endodontic activating devices were characterized in terms of tip displacement and cavitation performance using scanning laser vibrometry (SLV) and sonochemical analysis, respectively. The obtained results showed that activator tip displacements and speed correlate to established cavitation thresholds. The EndoUltra™ tip speed was measured to be 14.5 and 28.1 m/s at 45 and 91 kHz, respectively, which is greater than the threshold. The EndoUltra™ was found to be the only device that exceeds the cavitation thresholds (i.e. tip speed and displacement), as evident from laser vibrometry analysis, and subsequently yielded measurable cavitation quantified via sonochemical analysis. All other passive endodontic activation devices, despite ultrasonic oscillation, were unable to produce cavitation.

Accuracy of Computer-Aided Dynamic Navigation Compared to Computer-Aided Static Procedure for Endodontic Access Cavities: An in Vitro Study

Purpose: To analyze the accuracy of two computer-aided navigation techniques to guide the performance of endodontic access cavities compared with the conventional access procedure. Materials and Methods: A total of 30 single-rooted anterior teeth were selected, which were randomly distributed into three study groups: Group A—guided performance of endodontic access cavities through computer-aided static navigation system (n = 10) (SN); Group B—guided performance of endodontic access cavities through computer-aided dynamic navigation system (n = 10) (DN); and Group C—manual (freehand) performance of endodontic access cavities (n = 10) (MN). The endodontic access cavities of the SN group were performed with a stereolithography template designed on 3D implant planning software, based on preoperative cone-beam computed tomography (CBCT) and a 3D extraoral surface scan, and endodontic access cavities of the DN group were planned and performed by the dynamic navigation system. After endodontic access cavities were performed, a second CBCT was done, and the degree of accuracy between the planned and performed endodontic access cavities was analyzed using therapeutic planning software and Student’s t-test. Results: Paired t-test revealed no statistically significant differences between SN and DN at the coronal (p = 0.6542), apical (p = 0.9144), or angular (p = 0.0724) level; however, statistically significant differences were observed between the two computer-aided navigation techniques and the MN group at the coronal (p < 0.0001), apical (p < 0.0001), and angular (p < 0.0001) level. Conclusion: Both computer-aided static and dynamic navigation procedures allowed accurate performance of endodontic access cavities.

Clinicopathological and ultrastructural characterization of periapical actinomycosis

Background

The aim of the present study was to analyze the clinicopathological and the ultrastructural features of periapical actinomycosis (PA) cases.

Material and Methods

Data from the files of an oral pathology laboratory were retrieved and the findings of histopathological analysis were evaluated. Hematoxylin–eosin (HE), a modified Brown & Brenn, and Grocott stains as well as ultrastructural analysis using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) were utilized.

Results

Six cases were obtained, 4 females and 2 males, with a mean age of 34 year-old. Two cases were symptomatic, lower teeth and the anterior region were more commonly affected, and all cases were characterized by periapical radiolucencies. All cases presented sulfur granules with a ray-fungus or club-shaped pattern of the Splendore-Hoeppli phenomenon in HE-stained sections, with filamentous gram-positive bacteria aggregates highlighted by the modified Brown & Brenn stain. SEM analysis revealed abundant packed rod-like and filamentous bacteria associated with an extracellular amorphous material. EDX analysis showed predominant picks of calcium and sulfur in actinomycotic colonies.

Conclusions

Our findings suggest that PA manifests either clinically and radiologically as a non-specific and heterogeneous condition and that the actinomycotic colonies consist in a calcium- and sulfur-rich matrix. Furthermore, the results highlight the importance of submitting periapical specimens after surgical removal to histopathological analysis.

Key words:Actinomyces, actinomycosis, periapical diseases.

Endodontic Surgery Associated with Guided Tissue Regeneration Technique: Case Report

AbstractNon-surgical endodontic retreatment should always be the first option for reintervention when the initial endodontic treatment fails. The surgical treatment, called periradicular surgery, will be the procedure of choice when there is no success after the conventional endodontic retreatment. The purpose of this article is to describe clinical case of endodontic surgery, associated with guided tissue regeneration (GTR). A male patient, 24 years old, was referred for endodontic surgery on tooth 12 after two unsuccessful endodontic interventions. During the surgery, osteotomy, lesion curettage, apicectomy, retrograde obturation with Mineral Trioxide Aggregate (MTA), and filling of the bone failure with lyophilized bone and reabsorbable collagen membrane were performed. After six months of follow-up, the patient did not present any type of painful symptomatology. The endodontic surgery, associated with a technique of guided tissue regeneration, was efficient to solve this clinical case. Keywords: Endodontics. Apicoectomy. Guided Tissue Regeneration. Resumo O retratamento endodôntico não cirúrgico deve sempre ser a primeira opção de reintervenção quando o tratamento endodôntico inicial falha. Já o tratamento cirúrgico, ou cirurgia parendodôntica, será o procedimento de escolha quando não há sucesso após o retratamento endodôntico convencional. O objetivo deste artigo é descrever um caso clínico de cirurgia parendodôntica, associada à regeneração tecidual guiada (RTG). O paciente, gênero masculino, 24 anos, foi encaminhado para cirurgia parendodôntica no dente 12 após duas intervenções endodônticas sem sucesso. Durante a cirurgia foram realizadas manobras de osteotomia, curetagem da lesão, apicectomia, obturação retrógrada com Mineral Trióxido Agregado (MTA), além de preenchimento da falha óssea com osso liofilizado e membrana de colágeno reabsorvível. Após seis meses de acompanhamento do caso, o paciente não apresentou nenhum tipo de sintomatologia dolorosa. A cirurgia parendodôntica, associada à técnica de regeneração tecidual guiada, foi eficiente para solucionar este caso clínico. Palavras-chave: Endodontia. Apicectomia. Regeneração Tecidual Guiada.

Endodontic microsurgery. Part one: diagnosis, patient selection and prognoses

Historically, surgical endodontics has been viewed as a treatment of last resort, mainly due to poor outcomes as a result of limitations in materials and techniques. Contemporary techniques, modern materials and better visualisation have all led to an improvement in success rates, making endodontic microsurgery a valuable treatment option to certain patients. Such advances, however, are no substitute for skill in endodontic diagnosis and treatment planning, which can often prove challenging. A variety of tools are available to test for fractures and assess both periodontal and pulpal health. More advanced techniques such as cone beam computed tomography are often invaluable in pre-surgical assessment and diagnosis. Once an accurate diagnosis has been established, a favourable prognosis is explicitly linked to careful patient selection. Orthograde treatment, or retreatment, remains the gold standard for the majority of endodontic problems. However, there are a number of indications for surgery where orthograde treatment is either impossible, or less likely to be successful. It is paramount for any clinician undertaking endodontic surgery to have a detailed understanding of the local and systemic factors associated with successful treatment. Whilst there are few absolute medical contraindications, there are a number of conditions which may influence patient management and make treatment more challenging.

Assessment of the quality of endodontic re-treatment and changes in periapical status on a postgraduate endodontic clinic

OBJECTIVE

The aim of this study was to assess endodontic retreatment outcomes based on quality of obturation and healing.

MATERIALS AND METHODS

A total number of 223 radiographs of patients who had received endodontic retreatment during the period (2008-2015) at a postgraduate teaching clinic were selected. Unreadable radiographs were all excluded. From the original sample of 223 in total 24 radiographs were discarded. The final sample thus consisted of 199 root canal fillings. All radiographs were individually evaluated for the density of the root filling as well as the distance between the end of the root canal filling and radiographic apex based on a six-point scoring system. Subsequently, patients were reviewed and follow up periapical radiographs were exposed. The outcome of healing was assessed using the Periapical Index (PAI) scoring system. The data were analysed using Chi Square test (p < 0.05).

RESULTS

The study revealed that 78.9 % of the endodontic retreatments were both homogeneity and length acceptable. The corresponding figure was only 13.1 % before endodontic retreatment. Conversely, homogeneity and length unacceptable before endodontic retreatment was 47.2 % reducing to a mere 2.5 % after retreatment. The results were statistically significant (P < 0.001). There was over 80 % improvement in periapical healing following endodontic retreatment and this was also statistically significant (P < 0.001).

CONCLUSION

There was a significant improvement in outcome after endodontic retreatment on the postgraduate endodontic clinic. The success rate of endodontic retreatment was over 70 % which is in line with the endodontic literature. Radiographic follow up confirmed some 81 % improvement in healing rate following endodontic retreatment.

CLINICAL SIGNIFICANCE

Endodontic re-treatment cases are normally categorised as high complexity and as such referral to specialist settings should be considered to help improve treatment outcomes.

Evaluation of the outcome of various laser therapy applications in root canal disinfection: A systematic review

BACKGROUND

Any successful endodontic therapy requires elimination of the endodontic biofilms through meticulous root canal disinfection methods. Sodium hypochlorite (NaOCl) and ethylenediaminetetraacetic acid (EDTA) are the most common effective irrigants, in removing smear-layer from the coronal and middle thirds of the dental canals but reduced considerably towards the apical one third. In recent years, newly alternative treatment modalities have been proposed, including high-power lasers and antimicrobial photodynamic therapy (aPDT). Our work was conducted to evalaute the outcome of root canal disinfection in relation to the efficacy of various treatment modalities. Furthermore, every effort was made to present an overview of the aPDT outcomes, as a model for this application, and to propose laser parameters protocol with positive results.

METHODS

The electronic databases PubMed was searched from January 2013- January 2019. Our inclusive criteria based on laser therapy applications, as a model for root canal disinfection. The search terms utilised various combinations as follows: photodynamic therapy or antimicrobial photodynamic therapy or photoactivated disinfection or light activated disinfection or laser activated disinfection or laser therapy, and endodontic.

RESULTS

The results of this systematic review concluded that the effectiveness of aPDT and various laser wavelengths protocols, in removing endodontic biofilms from infected root canals, remains unattainable.

CONCLUSIONS

Study concluded that the combination of aPDT with antimicrobial irrigants could provide a synergetic effect. However, due to the heterogeneity of the selected studies and their limitations, in terms of lack of standardised protocol or discrepancy in the methodology, authors suggest further validated approaches to achieve optimal outcomes.

Nematode-Associated Bacteria: Production of Antimicrobial Agent as a Presumptive Nominee for Curing Endodontic Infections Caused by Enterococcus faecalis

Xenorhabdus and/or Photorhabdus bacteria produce antibacterial metabolites to protect insect cadavers against food competitors allowing them to survive in nature with their nematode host. The effects of culture supernatant produced by Xenorhabdus and Photorhabdus spp. were investigated against the multidrug-resistant dental root canal pathogen Enterococcus faecalis. The efficacy of seven different cell-free supernatants of Xenorhabdus and Photorhabdus species against E. faecalis was assessed with overlay bioassay and serial dilution techniques. Additionally, time-dependent inactivation of supernatant was evaluated. Among the seven different bacterial species, X. cabanillasii produced the strongest antibacterial effects. Loss of bioactivity in a phosphopantetheinyl transferase-deficient mutant of X. cabanillasii indicated that this activity is likely based on non-ribosomal peptide synthetases (NRPSs) or polyketide synthases (PKSs). Subsequent in silico analysis revealed multiple possible biosynthetic gene clusters (BGCs) in the genome of X. cabanillasii including a BGC homologous to that of zeamine/fabclavine biosynthesis. Fabclavines are NRPS-derived hexapeptides, which are connected by PKS-derived malonate units to an unusual polyamine, also PKS-derived. Due to the known broad-spectrum bioactivity of the fabclavines, we generated a promoter exchange mutant in front of the fabclavine-like BGC. This leads to over-expression by induction or a knock-out by non-induction which resulted in a bioactive and non-bioactive mutant. Furthermore, MS and MS² experiments confirmed that X. cabanillasii produces the same derivatives as X. budapestensis. The medicament potential of 10-fold concentrated supernatant of induced fcl promoter exchanged X. cabanillasii was also assessed in dental root canals. Calcium hydroxide paste, or chlorhexidine gel, or fabclavine-rich supernatant was applied to root canals. Fabclavine-rich supernatant exhibited the highest inactivation efficacy of ≥3 log₁₀ steps CFU reduction, followed by calcium hydroxide paste (≤2 log₁₀ step). The mean percentage of E. faecalis-free dental root canals after treatment was 63.6, 45.5, and 18.2% for fabclavine, calcium hydroxide, and chlorhexidine, respectively. Fabclavine in liquid form or preferably as a paste or gel formulation is a promising alternative intracanal medicament.

A novel zinc oxide eugenol modified by polyhexamethylene biguanide: Physical and antimicrobial properties

This study was to prepare and screen a novel root canal sealing agent modified by polyhexamethylene biguanide (PHMB) that was in accordance with the ISO 6876:2001 standard and to study its physical and antimicrobial properties. The modified sealers were produced by mixing a certain amount of zinc oxide with eugenol containing different concentrations of PHMB (0.05, 0.1, 0.2, 0.4, 0.6 and 0.8%) at a ratio of 1:1 (w/v). The setting time, flow, film thickness, solubility and dimensional change after solidifying were assessed to screen out the modified sealing agents that the physical properties met the mentioned standards. The modified direct contact test (DCT) was used to evaluate the antimicrobial activity against Enterococcus faecalis. The results suggested that when the concentrations of PHMB were 0.05, 0.1 and 0.2%, the modified root canal sealers showed the best performance in physical and antimicrobial properties.

Therapeutic effect of one-time root canal treatment for irreversible pulpitis

Objective

To compare the therapeutic effects of one-time root canal treatment versus two-time treatment in patients with irreversible pulpitis.

Methods

We classified 130 patients into a one-time treatment group (group A; n = 68) and a two-time treatment group (group B; n = 62) according to the number of patient visits. Clinical efficacy at 6 months and 1 year follow-ups as well as serum levels of interleukin-6, tumor necrosis factor alpha, and high-sensitivity C-reactive protein before and 1 week after endodontic treatment were observed. Additionally, the level of treatment satisfaction between the two groups was compared, and the degree of pain was evaluated using the visual analogue scale.

Result

One week after treatment, serum interleukin-6, tumor necrosis factor alpha, and high-sensitivity C-reactive protein levels were significantly decreased in the two groups; however, levels in group B were significantly lower than those in group A. Additionally, visual analogue scale scores of patients in group A were significantly higher than those of patients in group B.

Conclusion

One-time root canal therapy can effectively improve postoperative pain and the expression of inflammatory factors in the serum of patients undergoing treatment.

Relationship between unintentional canal overfilling and the long-term outcome of primary root canal treatments and nonsurgical retreatments: a retrospective radiographic assessment

AIM

To determine retrospectively the long-term radiographic outcome of root canal treatments and root canal retreatments with unintentional root canal overfilling.

METHODOLOGY

A total of 220 root canal treatments (143 primary/77 retreatments) with postoperative unintentional canal overfilling and performed by two endodontists during their 45 years of private practice were included in the study. Lateral condensation techniques and nine different sealers were used. Overfilling was confirmed with a postoperative periapical radiograph and patients were scheduled regularly for recall visits. Average recall time was 4.86 years (maximum = 30 years). Two calibrated observers evaluated the radiographs and determined the long-term outcome using the PAI score pooled in a 3-category scale. The persistence or resorption of the extruded material was registered. The Kappa coefficient (K) was calculated and a logistic regression was used for further analysis. Odds ratios and their 95% CI were estimated.

RESULTS

The level of inter-observer agreement was 66.1%. Primary root canal treatments had a significantly (P = 0.015) greater rate of success (91.6%) than retreatments (81.8%). Tooth location (P = 0.019) was the only other factor that significantly affected the outcome. The type of extruded material, and its resorption or persistence did not relate to the outcome. Persistence of extruded material was significantly affected by tooth location and recall time after treatment.

CONCLUSION

The outcome of root canal treatment with unintentional canal overfilling was not associated with the type of extruded material or its resorption or persistence. The persistence of extruded material did not relate to a favourable or unfavourable outcome.

An Insight into Advanced Approaches for Photosensitizer Optimization in Endodontics-A Critical Review

Apical periodontitis is a biofilm-mediated disease; therefore, an antimicrobial approach is essential to cure or prevent its development. In the quest for efficient strategies to achieve this objective, antimicrobial photodynamic therapy (aPDT) has emerged as an alternative to classical endodontic irrigation solutions and antibiotics. The aim of the present critical review is to summarize the available evidence on photosensitizers (PSs) which has been confirmed in numerous studies from diverse areas combined with several antimicrobial strategies, as well as emerging options in order to optimize their properties and effects that might be translational and useful in the near future in basic endodontic research. Published data notably support the need for continuing the search for an ideal endodontic photosensitizer, that is, one which acts as an excellent antimicrobial agent without causing toxicity to the human host cells or presenting the risk of tooth discoloration. The current literature on experimental studies mainly relies on assessment of mixed disinfection protocols, combining approaches which are already available with aPDT as an adjunct therapy. In this review, several approaches concerning aPDT efficiency are appraised, such as the use of bacteriophages, biopolymers, drug and light delivery systems, efflux pump inhibitors, negative pressure systems, and peptides. The authors also analyzed their combination with other approaches for aPDT improvement, such as sonodynamic therapy. All of the aforementioned techniques have already been tested, and we highlight the biological challenges of each formulation, predicting that the collected information may encourage the development of other effective photoactive materials, in addition to being useful in endodontic basic research. Moreover, special attention is dedicated to studies on detailed conditions, aPDT features with a focus on PS enhancer strategies, and the respective final antimicrobial outcomes. From all the mentioned approaches, the two which are most widely discussed and which show the most promising outcomes for endodontic purposes are drug delivery systems (with strong development in nanoparticles) and PS solubilizers.

Antimicrobial efficacy of the supernatant of Streptococcus dentisani against microorganisms implicated in root canal infections

The present study aimed to test the antimicrobial activity of Streptococcus dentisani (S. dentisani) supernatant against a collection of microorganisms implicated in dental root infections, and to analyze morphological changes induced in a selection of the tested microorganisms. A total of 22 microbial species were selected, and their growth was monitored by spectrophotometry in the presence and absence of the supernatant of S. dentisani at different assay concentrations (0.2×, 1×, 2×). The generation time and maximum growth rates were evaluated under every tested condition. Scanning electron microscope (SEM) images were obtained to assess the effect on the cell surface following incubation of the pathogens with the concentrated (2×) supernatant of S. dentisani. The supernatant of S. dentisani was found to exert effective inhibitory activity against most of the studied microorganisms implicated in dental root infections (20 out of 22). Total growth inhibition was observed in the case of Streptococcus oralis, Streptococcus sobrinus, Streptococcus salivarius, Prevotella intermedia, and Streptococcus mutans, while the rest of the microorganisms showed an increase in the generation time (between 30 min and 4 h). SEM images revealed structural changes in the membrane consistent with bacteriocin activity, although the effects were heterogeneous among the different species tested.