Endodontic Failure Research Articles

A Comparison of Conventional Root Canal Sealers With Ones That Use Green Synthesized Nanoparticles for Antimicrobial Activity: Protocol for a Systematic Review.

Root canal failure and secondary endodontic infection are frequent clinical scenarios in dentistry. The main microorganisms implicated in root canal therapy failure are persistent Enterococcus faecalis, Candida albicans, and Staphylococcus aureus. To combat the impact of disease resistance, scientists are concentrating on alternative antimicrobial root canal sealers. Nanomaterials are a recent development in endodontic materials that exhibit great antimicrobial properties, making them an ideal material choice for root canal sealers. This systematic review aims to compare the antimicrobial properties of conventional root canal sealers to those incorporating green synthesized nanoparticles between 2010 and 2024. A well-constructed protocol was established and registered with PROSPERO (CRD42021286373). Ethics approval was obtained from the Biomedical Research and Ethics Committee from the University of the Western Cape (UWC; BM22/1/4). PRISMA-P (Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols) reporting guidelines were followed. The included criteria demonstrate the green synthesized nanoparticles studies where the nanoparticles (NPs) are incorporated in root canal sealers. MeSH (Medical Subject Headings) terms were used for the search strategy of the systematic electronic databases for articles published in English between 2010 and 2024. The selected databases included Scopus, PubMed, Web of Science, Science Direct, EBSCOhost, SpringerLink, and Wiley Online. A quality assessment tool for laboratory studies will be used to critically appraise the included studies. If applicable, statistical measures (mean, SD, etc) will be used for data analysis and presentation of the results. The protocol is registered with PROSPERO. A preliminary search was conducted using a determined search strategy across 8 electronic databases, and the review is now complete. It is anticipated that the results of this systematic review may reveal the increased interest and application for nanoparticle-enhanced root canal sealers. This will aid in the future development of root canal sealants and mitigate the risk of endodontic failure. PROSPERO CRD42021286373; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=286373. DERR1-10.2196/51351.

A first step towards the detection of damage processes in endodontic Ni-Ti alloy files, using acoustic emission

Despite major instrumental developments over the last decade, endodontic files are still not infallible. It is well known that NiTi rotary files can break without any visible sign of deformation. Instrument breakage under combined flexion-torsion loading is still common in clinical practice. Unfortunately, breakage of this type of instrument mainly occurs in narrow canals, through pinching in the apical region. When such an incident occurs, the endodontist must adopt a debris retrieval strategy that is both stressful and not guaranteed success. This study proposes a new method for experimental damage detection leading to the fracture of Ni-Ti shape memory alloy endodontic files. It is based on the acoustic emission (AE) technique and mechanical parameters measured in real-time and image analysis. It has been shown that the AE results correlate with the damage observations and torque and force measurements recorded during the tests.Having carried out numerous root canal treatment on resin blocks, it appears that this new detection and analysis technique can be used to analyze and anticipate the first signs of damage leading to endodontic file failure. The technological development of such a method, at the level of the engine itself, associated with the act in service procedure, would constitute a revolution in the field of endodontics.

The Middle Mesial Canal: Combined Endodontic and Restorative Treatment Approach - A Case Report

The management of the middle mesial canal (MMC) in mandibular first molars presents considerable challenges during endodontic treatment due to its complex anatomy. Challenges may arise throughout various stages of treatment, including canal location, instrumentation, and obturation. The inability to identify and shape this canal can lead to endodontic failure and post-treatment apical periodontitis. Therefore, understanding this aberrant root canal anatomy and its clinical implications during the various stages of endodontic treatment is essential for successful management, including the selection of the optimal coronal restoration to enhance the efficacy of the obturation’s coronal seal and to ensure the restoration’s maximal longevity. This case report describes the diagnosis and successful endodontic and restorative management of an MMC in a mandibular first molar.

Achieving excellence with interdisciplinary approaches in complex orthodontic adult patients

Over the last decades the percentage of adult orthodontic patients has substantially increased. Undeniably, an important motif for seeking orthodontic care at an older age is smile improvement, but this is not all. Frequently, impaired dentofacial aesthetics are combined with several other issues: severe dentoskeletal malocclusions; multiple tooth loss due to caries or endodontic failure; dental agenesis or trauma; periodontal breakdown; or functional problems, such as temporomandibular disorders or obstructive sleep apnoea. Therefore, comprehensive adult treatment mostly requires close collaboration of a team of equally well-trained dental specialists to select and execute the most suitable treatment option for the individual patient from day one. With joint planning, intensive communication with the patient and the involved specialists, and continuous monitoring of the treatment process, true patient-centred care can be delivered. In order to serve the individual patient best, the treating orthodontist does not only need thorough speciality training and continuing education, but furthermore, should be well-equipped with sufficient knowledge of the other dental fields of expertise. In combination with digital technology as an important tool for enhancing communication and efficient exchange of information between all involved team members, excellent joint clinical skills will take comprehensive interdisciplinary treatment to the next level.

Assessment of the Difference Between General Practitioners and Specialists in Antibiotic Prescription for Emergency Patients

Background:Endodontic emergencies are one of the most common emergencies that dentists face during their career. Objectives: This study aimed to evaluate and assess the difference between general dentists and endodontists in managing endodontic emergency cases. Also, it highlights the risk of bacterial resistance due to an inappropriate antibiotic prescription. Methods: A cross-sectional study conducted at King Abdul-Aziz University Dental Hospital, a self-administered survey was distributed to 521 dental patients. The response rate was 82.9% (432 out of 521). The survey, available in both paper and electronic formats, comprised 24 questions organized into three main sections: the first section collected demographic and medical history data, the second focused on the patients' dental history related to emergencies, and the third detailed the treatment received during emergencies and the methods employed. A Fisher's exact test was utilized to assess significant differences between general dental practitioners and endodontic specialists regarding their initial steps, reasons for treatment, swelling conditions, biting and chewing conditions, and final treatments. Data analysis involved simple descriptive statistics, including percentages, frequency distributions, pie charts, and bar graphs. Statistical significance was determined with a p-value set at ≤ 0.05. Results: The study revealed that decay was the most prevalent reason for endodontic treatment, with immediate treatment being the preferred choice among dentists. Despite the well-documented issue of endodontic treatment failure due to inadequate coronal sealing, the majority of general dentists performed root canal treatments followed by either temporary or permanent restorations. Additionally, the study found that general dentists prescribed antibiotics more frequently than endodontists. Conclusion: The study findings indicate the need to develop intervention programs targeting clinicians to enhance knowledge about prescribing antibiotics for endodontic emergencies.

Comparative evaluation of postoperative pain and periapical healing after root canal treatment using three different endodontic sealers: A randomized controlled clinical trial.

A randomized controlled clinical trial to evaluate postoperative pain and investigate periapical healing after root canal treatment using eugenol, resin-based, and calcium silicate-based sealers (CSBSs) sealers. Sixty-three individuals diagnosed with apical periodontitis confirmed using cold test and electronic pulp tester, periapical pathology with periapical index score of 2 or more, previous endodontic treatment failure exhibiting a visual analog scale pain score of 3 or above, were enrolled in this investigation. The patients were randomly allocated into three groups and following biomechanical preparation, the canals were obturated using Meta CeraSeal, AH plus, and eugenol-based sealers. Postprocedural pain intensity was assessed at 24 h, 48 h, and 7 days, while periapical healing was evaluated at 3- and 6-month follow-ups. Statistical analysis was done using the Chi-square and Friedman's test. The mean of periapical lesions for Meta CeraSeal (4.7, 1.6), AH Plus (4.68, 3.19), 24 and eugenol-based (2.66, 1.75) at 3 months and 6 months, respectively. The mean & std. deviation of pain scores at 24 h for Meta CeraSeal (0.62 ± 1.857), AH Plus (1.62 ± 1.962), and eugenol-based (0.48 ± 1.250). At 48 h for Meta CeraSeal (0.33 ± 1.528), AH Plus (1.33 ± 1.798). On the 7th day, Meta CeraSeal (0.24 ± 1.091) and AH Plus (0.71 ± 1.384) for eugenol-based at 48 h, and on the 7th day, none of the patients had pain. Evaluation of the apical sealer puff displayed no suggestive variations (P = 0.634). Notably, no analgesics were taken. No suggestive dissimilarity was noted between eugenol, resin-based, and CSBSs sealers.

Iatrogenic Root Perforations: Case Report

Root perforation, a connection between the root canal system and tooth surface, is a common cause of endodontic therapy failures. Caused by pathological conditions or operative errors, it can occur during access cavities, root canal preparation, or post-preparation. A 28-year-old patient was diagnosed with a vestibular medium-sized infra-osseous perforation during root post realization. Despite no systemic disorders, the patient showed physiologic movement and was slightly sensitive to pressure. A flap surgical treatment was chosen to remove excess material and enable tissue regeneration. Biodentine® was used to prevent future discolorations. The patient underwent an intrasulcular incision, flap raised, cavity cleaned, disinfected, revised, and sealed using an anterior Schilder plugger. Root perforations are common errors caused by factors like anatomy, caries, pulp calcifications, and intracanal posts. Diagnosis is based on clinical signs, radiographic examinations, and imaging techniques. The prognosis depends on preventing bacterial infection. The ideal reparation material should stimulate bone formation, be biocompatible, maintain sealing, and not disintegrate in tissue fluid. Equivalent materials like Biodentine® offer advantages in protocol, antibacterial power, and bioactive properties. Radicular perforations, a significant dental issue, can be prevented through early management using modern techniques and clinical training, ensuring long-term success in endodontic treatments.

In Vitro Investigation of Antibacterial Activity of Gum Arabic Prepared by Two Different Processing Methods against Enterococcus Faecalis

Introduction: Entrococcus faecalis is a known cause of endodontic treatment failure. Synthetic drugs have been preferred for decades, but recently, many plants have been reported for their antibacterial activity. The study was carried out to investigate the antibacterial effect of Gum Arabic (GA) processed with two different processing methods against Enterococcus faecalis.

Analysis of Endodontic Successes and Failures in the Removal of Fractured Endodontic Instruments during Retreatment: A Systematic Review, Meta-Analysis, and Trial Sequential Analysis.

This study presents a systematic review with meta-analysis to evaluate the success rates of endodontic retreatments in teeth where separated instruments are located within the roots. The search and selection of studies were conducted across two databases, SCOPUS and PubMed, as well as the Cochrane Library registry, yielding a total of 1620 records. Following the selection process, 11 studies were included in the systematic review. Overall, out of 1133 retreated teeth, there were 172 failures in instrument removal and 55 perforations. The meta-analysis results indicate that failures are more frequent when instruments are located in the apical third, with a failure rate of 21%, compared to an 8.8% failure rate in the middle/coronal third. The anatomy of the root canals, particularly the location of the separated instruments, significantly influences the success rates.

Can antimicrobial photodynamic therapy serve as an effective adjunct protocol for disinfecting the necrotic root canal system? A randomized controlled study

BackgroundBacterial infection plays an important role in persistent periapical lesions and inadequate disinfection of root canals is considered the biggest factor responsible for endodontic treatment failure. Antimicrobial Photodynamic Therapy (aPDT) has become the latest choice to eradicate microorganisms in root canals.ObjectiveThis study aims to evaluate the effectiveness of Antimicrobial Photodynamic Therapy (aPDT) in bacterial count reduction compared to Passive Ultrasonic Activation (PUI) and Ca(OH)2 dressings.Materials and methodsForty-five anterior single canal teeth with medium-sized periapical lesions (2–5 mm) were divided into three groups according to the disinfecting technique (each group consists of 15 canals with 1:1:1 allocation ratio): Group A: Ca(OH)2 dressing. Group B: Passive Ultrasonic Activation (PUI). Group C: Antimicrobial Photodynamic Therapy (aPDT). Direct bacterial viable count method was used to count the colonies forming units (CFU) before and after the disinfecting and the bacterial count reduction was estimated, the statistical analysis was performed at a 95% confidence level using the Chi-square and Mann–Whitney U test.ResultsaPDT showed no statistically significant difference when compared to passive ultrasonic irrigation (P > 0.05) but showed higher and more promising results when compared to Ca(OH)2 dressings (P < 0.05).ConclusionsaPDT has the ability and effectiveness as a disinfecting technique in necrotic and infected root canals.Clinical significance of the studyThe results of this clinical trial provide that aPDT can be considered an adjunct method for root canal disinfection with the same effectiveness as passive ultrasonic irrigation.

Quest for hidden alley- hide &amp; Seek in mandibular anteriors

Failure is the good teacher than success. When returning to the root canal system for retreatment, there is always a lesson to be learned. An often cited reason for endodontic failure is the inability to identify, access, treat, and fill every single canal. Mandibular incisor teeth are not an outlier to this rule. Mandibular incisors are one such tooth which is regarded as least difficult for endodontic treatment. But the intricacy of the mandibular incisors internal anatomy presents us with various challenges during root canal treatment. Prevention of missing anatomy commences with adequate pre-operative radiographs, notwithstanding the limitations of radiography in estimating the number of canals and the presence of auxiliary canals and anastomoses. Without a second thought, a correct access cavity preparation is crucial to localising the root canal orifices, and this also calls for a comprehension of the tooth's internal architecture. This case series highlights the non- surgical endodontic retreatment of mandibular incisors with missed canal.

Survival analysis of teeth following clinical crown lengthening and crown insertion procedures up to 14 years: A retrospective cohort study.

The purpose of this study was to conduct survival analysis of teeth following clinical crown lengthening procedures (CLPs) and crown insertions via a retrospective cohort study. Patient- and tooth-related data were collected from 268 participants who received CLPs from 2009 to 2015. The Kaplan-Meier curve and the log-rank tests were used to estimate the probability of survival and compare the survival probabilities among different variables. A Cox multivariate proportional hazard regression model was used to investigate the collective effects of root canal treatment (RCT) and the types of opposing dentition. The rate of tooth loss was 21.6% during the observation period from 1 to 14 years, with 58 teeth extracted. The most attributable reason for tooth extraction was coronal tooth fracture, followed by endodontic failure such as root fracture. The survival probability was 0.87 at 5 years and 0.7 at 10 years. No significant differences in the survival probabilities were found among different providers and locations, the presence of a post, and the types of crowns. The hazard ratio for tooth loss was 6.3, 95% confidence interval (CI) [2.6 to 20.9] in the teeth with RCT (p<0.001) and 2.4, 95% CI [1.1 to 4.8] in the teeth occluding implant-retained prostheses (p=0.016). Tooth loss following CLPs and crown insertions appeared least among the teeth without RCT when occluding natural teeth, while tooth loss was most among the teeth with RCT when occluding implants.

Assessment of microbial reduction following rapid chair-side sterilization of contaminated endodontic files

Background. Endodontic treatment is carry out in order to preserve a tooth whose pulp has been damaged where the injury extends to the peri-radicular tissue. The endodontic treatment is cleaning, disinfection of the root canal space and shaping it, followed by the obturation of the root canal system. The presence and re-entry of microbes inside the canal is the main reason for post-treatment infections, which is considered as an endodontic failure. Therefore, disinfection throughout the treatment is very important. The aims of the study were to find microbial growth on brand sealed endodontic files, taken directly from the manufacture's packages, compare between different chemical compounds in rapid sterilization of contaminated endodontic files and determine the most effective chemical method in the sterilization. Methods. The present study was performed to compare between different chemical compounds: 3% sodium hypochlorite, dendroid, chloroX and saline as the positive control in rapid sterilization of endodontic files in root canal treatment in dental practice using sealed endodontic files, taken directly from the manufacture's packages and sterile K-files sterilize by autoclaving. Results. The results of this study, concerning E. coli bacteria, indicated that Dentroid scored the best results (90% free of any E. coli bacteria), followed by CHX (20% free of E. coli bacteria), then 3% NaOCL (10% free of E. coli bacteria). The results, concerning S. aureus, showed that normal saline and 3% NaOCL scored the highest contamination percentages (100%). While least and equal distribution of CHX and dentroid (90% free of S. Aureus). Conclusion. The disinfecting solutions as CHX and Dentroid could be used as a method of rapid chair-side sterilization in clinical practice.

Predicting early endodontic treatment failure following primary root canal treatment

BackgroundUnderstanding when and why endodontic treatments fail could help clinicians make prognoses and thus improve treatment outcomes. This study was aimed to assess potential predictors of early endodontic treatment failure. We explored factors contributing to the failure of initial root canal treatment were explored, with a specific emphasis on evaluating the influence of the time elapsed since the initial treatment.MethodsThis retrospective cohort study enrolled 1262 patients who sought endodontic treatment at our department and 175 patients were included for analysis. Potential causes of endodontic treatment failure were investigated, such as inadequate obturation quality, inadequate coronal status, the presence of additional untreated canals, anatomical complexity, instrument separation, iatrogenic perforation, cracks, and endodontic-periodontal lesions. The patients were divided into “short-term” and “long-term” groups depending on the time that had passed since the initial treatment (i.e., < 5 and > 10 years, respectively). The causes of failure in the short-term and long-term group were analyzed and compared using logistic regression analyses. Subgroup analysis was performed according to the number of years since the initial treatment in the short-term group to further investigate the association between the time and cause of failure (i.e., < 1, 2, 3, and 4 years, respectively).ResultsUntreated additional canals were present in 21.7% of all cases, and in 36.9 and 6.4% of cases in the short-term and long-term groups, respectively. Multivariable analysis showed that the presence of untreated additional canals was significantly associated with short-term compared to long-term failure. Untreated additional canals were also associated with endodontic failure within 1, 2, 3, and 4 years.ConclusionsThe presence of untreated additional canals was a predictor of endodontic failure within 5 years following initial root canal treatment. To optimize long-term prognosis, it is important to detect and treat all root canals during the initial treatment.

Clinical, radiographic and histological findings of seven teeth from two California sea lions (Zalophus californianus) housed under professional care.

Seven teeth extracted from two adult California sea lions (Zalophus californianus) due to pulp exposure and/or to gain access to the mandibular canine teeth were histologically evaluated, and the findings were compared with clinical and radiographic findings. Three teeth were diagnosed with pulp exposure, and two of these showed no radiographic signs of endodontic disease and were histologically vital with prominent coronal pulpitis and a pulp polyp. Another tooth with pulp exposure was showing clinical and radiographic signs of endodontic disease and was histologically confirmed with pulp necrosis. A discoloured incisor tooth was showing radiographic signs of endodontic disease and was also histologically non-vital. Two clinically and radiographically healthy mandibular first premolar teeth and one second incisor tooth had no evidence of pulpitis or pulp necrosis but had pulp canal obliteration. Regular clinical and radiographic follow-up for 5 months to 3 years after the procedures confirmed uneventful healing of the extraction sites, despite initial flap's dehiscence. Although extractions of affected teeth in California sea lions are considered the most practical and beneficial therapy, these are associated with the risks of extensive trauma and anaesthesia and the need to perform these surgical procedures on-site under variable conditions. As California sea lions can be trained to allow conscious dental radiographic re-checks, monitoring teeth with clinical signs of pulp polyp formation and without radiographic signs of endodontic disease warrant further evaluation/reconsideration from previous recommendations. Endodontic treatment of abscessed teeth in California sea lions is reportedly unsuccessful and is discouraged. However, vital pulpectomy could be an alternative treatment to extraction in teeth with pulp polyps as it was found to be highly successful in humans, but the possibility of endodontic failure and need for further treatments should be weighted in the treatment choice.

ISOLATION AND IDENTIFICATION OF BIOFILM PRODUCING ENTEROCOCCUS FAECALIS FROM ROOT CANAL

This study was aimed to one of the most prevalent causes for endodontic treatment failure is the presence of Enterococcus faecalis bacterium within teeth root canals. To achieve successful treatment, it is so important to study E. faecalis behavior. The aim of study was to investigate biofilm production and antibiotic sensitivity of E. faecalis isolated from root canals. Results showed isolation of E. feacalis (65%) of samples, identified by specific gene by PCR technique. Most isolates were sensitive to Imipenem and resistant to Erythromycin, Clindamycin, Tetracycline and Trimethoprim. Strong biofilm production was detected among 29.5% of highest antibiotic resistant isolates. The results may indicate that infected root canals with E. feacalis may lead to serious complication for patients.

The association of endodontic prognostic factors with the presence of periapical lesion, its volume, and bone characteristics in endodontically treated molars: a cross-sectional study

BackgroundThis study intended to evaluate the association between several endodontic prognostic factors with the presence of periapical lesions (PLs), their volume, and bone characteristics including cortical bone destruction (CBD) and buccal plate bone height (BPBH) in root-filled molar teeth using cone-beam computed tomography.MethodsA collection of 143 scans of endodontically treated maxillary/mandibular first or second molars recorded over 8 years, were obtained from a specialized radiology center. Data on prognostic factors including tooth number, gender, jaw type, the status and number of missed canals, obturation length, restoration type, presence of a separated instrument, presence of a post or screw in the canals, and presence of perforation were collected. The assessed outcomes included PL presence, PL volume, CBD, and BPBH. The association between prognostic factors and outcomes was evaluated using multiple logistic regression models with adjusted covariates and multifactorial ANOVA at a significance level of 0.05.ResultsA total of 282 molars from 82 women and 50 men with a mean age of 40.6 ± 12.27 were included. Among those, 139 teeth presented PL with a mean volume of 18.68 mm3. CBD was prevalent in 137 teeth and the mean BPBH appeared to be 9.45 mm. The presence of a missed canal (OR = 10.022, P < .05), underfilled canal (OR = 3.725, P < .05), overfilled canal (OR = 15.859, P = .018), and perforation (OR = 15.261, P = .013) was significantly associated with PLs. None of the prognostic factors could considerably contribute to the CBD (P > .05). The presence of a missed canal was positively associated with the PL volume (P < .05). Similarly, missed canals (P < .05), perforation (P < .05), and separated instruments (P = .004) were associated with a significantly reduced BPBH.ConclusionsOverfillings, perforations, missed canals, and underfillings were identified as remarkable predictors of PL, arranged in descending order of their respective impact. The only factor capable of significantly increasing the PL volume was the missed canal. In brief, obturation length errors, perforations, missed canals, and separated instruments were robustly correlated with endodontic failure, which highlights the importance of mitigating the potential for errors by following the fundamentals of endodontics.

Antimicrobial Efficacy of Calcium Hydroxide with Different Herbal Additives: An In-vitro Study

Introduction: Microorganisms such as Enterococcus faecalis, Enterobacteriaceae, and Candida albicans are associated with persisting infections and can cause endodontic failure. The addition of herbal additives such as Triphala, Clove, and Activated charcoal to Calcium hydroxide enhances the microbial efficacy within the root canal. Aim: To evaluate and compare the anti-microbial efficacy of calcium hydroxide with various herbal additives against E. faecalis and C. albicans using Agar Diffusion Test (ADT) and Direct Contact Test (DCT). Materials and Methods: The present in-vitro study was conducted in Bangalore, Karnataka, between July 2023 and September 2023. Ethical clearance was obtained from the institution. Sabouraud Dextrose Agar (SDA) and Mueller-Hinton Agar were prepared and used to culture C. albicans and E. faecalis, respectively. In each plate, four wells were filled with groups (n=10): Group-I: Nanocalcium hydroxide (NCH)+sterile distilled water, Group-II: NCH+Nanoparticle Clove, GroupIII: NCH+Nanoparticle Triphala, Group-IV: NCH+nanoparticle activated charcoal. The plates were incubated at 37°C, and zones of inhibition around the wells were measured on the first, third, and seventh day. DCT was evaluated in Colony Forming Units (CFUs)/ml by adding each bacterial suspension to four groups and inoculating on blood agar plates. One-way ANOVA test followed by Tukey’s post-hoc analysis was used to compare the mean Zone Of Inhibition (ZOI). Kruskal-Wallis Test followed by Mann-Whitney post-hoc test was used to compare the mean CFUs. Results: One-way ANOVA test showed that there was a significant difference in the mean ZOI between the four groups at p=0.005. The maximum mean ZOI against C. albicans was achieved by the combination of calcium hydroxide and clove with an average mean of 22.20±1.92 mm, 20±1.87 mm, and 17.20±2.28 mm on the 1st, 3rd, and 7th day, respectively. Calcium hydroxide with distilled water combination showed the highest mean ZOI against E. faecalis with an average mean of 18.20±0.84 mm on day 1, 17±1 mm on the 3rd and 7th day. The mean CFUs of E. faecalis and C. albicans showed a significant difference between the four groups at p&lt;0.001. Conclusion: The addition of herbals to Calcium hydroxide increased anti-microbial activity against Candida albicans and Enterococcus faecalis.

Photodynamic Therapy With Resveratrol and an Nd:YAG Laser for Enterococcus faecalis Elimination.

Enterococcus faecalis is the leading cause of endodontic treatment failures. Despite various conventional disinfection approaches, microorganisms often persist in root canals. Photodynamic therapy (PDT) is an adjunct antimicrobial strategy employing a nontoxic photosensitizer (PS) and light source. This study evaluated the antimicrobial effect of PDT using an Nd:YAG laser and resveratrol (RSV) with or without pigment, and confirmed that RSV is nontoxic as a PS. We employed laser irradiation at a 3W output power, using RSV and red pigment as the PS, on an E. faecalis bacterial solution. Subsequently, colony-forming units were quantified. The impact of RSV on osteoblasts was measured using an MTT assay. E. faecalis counts declined after laser irradiation. The combined application of laser irradiation with RSV, red pigment, or both showed a reduction compared to no irradiation and control groups without RSV and red pigment. The 50% cytotoxic concentration against osteoblast cells from mice incubated with RSV for 48 h was 162 μM. The value with RSV and laser was 201 μM and that with RSV and red pigment was 199 μM. The value with RSV, laser and red pigment was 357 μM. The combination of Nd:YAG laser irradiation and RSV as the PS with pigment was efficacious for E. faecalis elimination without inducing any toxic effects on osteoblasts. This combination holds potential as a root canal irrigation strategy.

Strategies and mechanisms targeting Enterococcus faecalis biofilms associated with endodontic infections: a comprehensive review.

Enterococcus faecalis is one of the main microorganisms that infects root canals, ranking among the most prevalent microorganisms associated with endodontic treatment failure. Given its pervasive presence in persistent endodontic infections, the successful elimination of Enterococcus faecalis is crucial for effective endodontic treatment and retreatment. Furthermore, Enterococcus faecalis can form biofilms - defense structures that microbes use to fight environmental threats. These biofilms confer resistance against host immune system attacks and antibiotic interventions. Consequently, the presence of biofilms poses a significant challenge in the complete eradication of Enterococcus faecalis and its associated disease. In response, numerous scholars have discovered promising outcomes in addressing Enterococcus faecalis biofilms within root canals and undertaken endeavors to explore more efficacious approaches in combating these biofilms. This study provides a comprehensive review of strategies and mechanisms for the removal of Enterococcus faecalis biofilms.