The effect of chlorhexidine as an endodontic disinfectant

Microbiological assessment of success and failure in pulp revitalization: a randomized clinical trial using calcium hydroxide and chlorhexidine gluconate in traumatized immature necrotic teeth

Aim

To compare differences in the disinfection efficacy of calcium hydroxide (CH) and chlorhexidine gluconate (CHD) dressings in pulp revitalization (PR) of traumatized immature necrotic teeth; to investigate the microflora in successful/failed PR and whether bacterial persistence influences the outcomes of PR.

Methods

Microbiological assessment of the average bacterial load (CFU/sample) and bacterial diversity (taxa/sample) was performed on 41 teeth at three timepoints (S2-before, S3-after debridement and S5- after root canal dressing).

Results

The primary microflora was more diverse in successful cases than in failed. Decreases in CFU/sample and taxa/sample occurred S2 - S3, though new increases occurred at S5 in the CHD subgroup (successful and failed) and CFU/sample in the CH subgroup (failed). At S5, the successful cases showed more bacterial decreases. No specific species was associated with the outcomes with no statistical differences between the disinfection efficacy.

Conclusions

There were no statistical differences in CH and CHD efficacy. At S5, microflora persisted in both successful and failed outcomes, but the abundance and diversity increased significantly only in the failed cases. The successful outcomes presented higher diversity and higher decreases of the primary microflora at S5 than the failed outcomes. The abundance and diversity increased significantly at S5 only in failed cases.

Evaluation of the Anti-microbial Efficacy of a Novel Endodontic Irrigant Against Enterococcus faecalis: An In Vitro Study

INTRODUCTION

Enterococcus faecalis is a constant microbiome that plays an inevitable role in the etiology of peri radicular lesions after endodontic treatment, chronic and, apical periodontitis and, recently, in periimplantitis. The effective biomechanical preparation and the use of potent irrigating solutions will permit bacterial neutralization and toxin inactivation, leading to the success of endodontic treatment. This study aimed to evaluate the "anti-microbial" efficacy of simvastatin (SMV) against E. faecalis as an endodontic irrigant.

MATERIALS AND METHODS

In this invitro experimental study, the antimicrobial efficacy of SMV was evaluated against E. faecalis using the agar diffusion method. The samples were divided randomly into the following groups. GROUP 1: SMV solution 1 μM/L concentration, GROUP 2: SMV solution 5 μM/L concentration, GROUP 3: SMV solution 10 μM/L concentration, GROUP 4: 2% chlorhexidine gluconate (CHX) solution (positive control), and GROUP 5: normal saline (negative control). Linear measurement was done by measuring the zones of inhibition around the medicaments in the cavities in millimeters. Results were tabulated.

RESULTS

The results of the study have shown the zone of inhibition of Group 4 (2% CHX solution) is 19 mm, which demonstrated the best outcome. When comparing the test samples, Group 3 (SMV solution 10 M/L concentration) has the best zone of inhibition, measuring 14 mm, followed by Group 2 (SMV solution 5 M/L concentration), which is 9 mm.

CONCLUSION

The results of this in vitro study have proven that SMV's anti-microbial activity, albeit less potent than CHX in this in vitro investigation, has demonstrated that it can be utilized as an efficient endodontic irrigant.

Traditional and Recent Root Canal Irrigation Methods and Their Effectiveness: A Review

According to contemporary dental standards, the primary goal of endodontic therapy is the chemo-mechanical cleaning of the complex root canal system. Watering root canals with approved solutions and activating them are essential parts of this operation. This review outlines various irrigant activation methods for root canal therapy. Specifically, a comparison among the methods of manual dynamic activation, sonics (subsonic, sonic, and ultrasonic), internal heating, and lasers, was conducted. The results in this work were gathered using Scopus, Web of Science, Google Scholar, and PubMed databases by searching the following keywords: sodium hypochlorite, cleaning, activation, and irrigation methods. The present work concluded that the use of irrigant activation has a greater benefit than its absence. Regardless, it is impossible to point to a single effective activation method.

Outcome of single-visit- versus two-visit root canal retreatment in teeth with periapical lesions: a randomized clinical trial

AIM

To evaluate the clinical and radiographic outcome of single-visit root canal retreatment and to compare the results with conventional two-visit root canal retreatment as control group.

METHODOLOGY

One hundred root canal-treated, single-rooted asymptomatic teeth with periapical lesion were retreated by one operator. Fifty of the teeth were randomly assigned to the single-visit group and the others were treated in two-visits. In both groups, root canal filling material was removed, and re-instrumentation of the root canal was performed using step-back technique with hand files using 2.5% NaOCl and 5% EDTA as irrigants. In the single-visit group 5 ml 2% chlorhexidine (CHX) were applied as the final irrigation and in the two-visit group, calcium hydroxide paste was placed into the root canal as an interappointment dressing. All root canal obturations were performed with lateral compaction. All patients were followed up for 24 months. Success was determined depending on both healed and healing cases. The chi-square or Fisher's Exact test was used to analyse the differences between the groups for success rates and the factors affecting the outcome.

RESULTS

The recall rate was 89 (89%). At 24 months, 39 teeth (88.6%) were considered as healed, 3 teeth (6.8%) as healing, and 2 teeth (4.5%) were identified as failed in the single-visit group, while in the two-visit group 39 teeth (86.7%) had healed, 2 teeth (4.4%) were scored as healing, and 4 teeth (8.9%) as failed. There was no statistically significant difference in the success rates between the two groups (P > 0.05). Size of the lesion and the preoperative length of root canal filling had a statistically significant impact on the outcome (P < 0.05).

CONCLUSION

No statistically significant difference was observed in terms of healing in 24-month follow-up of retreatments completed in single-visit or two-visits in asymptomatic teeth with periapical lesions. Size of the periapical lesion and initial apical level of root canal filling have affected the outcome of root canal retreatment.

Microbiological Aspects of Root Canal Infections and Disinfection Strategies: An Update Review on the Current Knowledge and Challenges

The oral cavity is the habitat of several hundreds of microbial taxa that have evolved to coexist in multispecies communities in this unique ecosystem. By contrast, the internal tissue of the tooth, i.e., the dental pulp, is a physiologically sterile connective tissue in which any microbial invasion is a pathological sign. It results in inflammation of the pulp tissue and eventually to pulp death and spread of inflammation/infection to the periradicular tissues. Over the past few decades, substantial emphasis has been placed on understanding the pathobiology of root canal infections, including the microbial composition, biofilm biology and host responses to infections. To develop clinically effective treatment regimens as well as preventive therapies, such extensive understanding is necessary. Rather surprisingly, despite the definitive realization that root canal infections are biofilm mediated, clinical strategies have been focused more on preparing canals to radiographically impeccable levels, while much is left desired on the debridement of these complex root canal systems. Hence, solely focusing on "canal shaping" largely misses the point of endodontic treatment as the current understanding of the microbial aetiopathogenesis of apical periodontitis calls for the emphasis to be placed on "canal cleaning" and chemo-mechanical disinfection. In this review, we dissect in great detail, the current knowledge on the root canal microbiome, both in terms of its composition and functional characteristics. We also describe the challenges in root canal disinfection and the novel strategies that attempt to address this challenge. Finally, we provide some critical pointers for areas of future research, which will serve as an important area for consideration in Frontiers in Oral Health.

Comparative evaluation of chlorhexidine and cetrimide as irrigants in necrotic primary teeth: An In vivo study

Context:

Disinfection of the root canal system by biomechanical preparation and profuse irrigation is especially important in primary teeth due to its complex pulp canal anatomy. Appropriate selection of irrigating solution should be done in terms of tissue dissolving capacity, antibacterial efficacy, and palatability when treating pediatric cases.

Aim:

The aim of the study was to compare the antibacterial efficacy of 2% chlorhexidine (CHX), 0.2% cetrimide (CTR), and 0.2% CHX + 0.2% CTR against anaerobic bacteria and to test the influence of CTR added to CHX on its antibacterial action.

Materials and Methods:

Seventy-five teeth that were selected for the study were divided into three groups: Group I (2% CHX), Group II (0.2% CTR), and Group III (0. 2% CHX + 0.2% CTR). Samples collected before and after irrigation were immediately processed and microbial growths were quantified.

Statistical Analysis:

Intergroup comparison was done using one-way analysis of variance and Newman–Keuls multiple post hoc procedures and intragroup comparison was done using paired t-test.

Results:

When the mean values of Group I were compared with Group II, the data were statistically not significant (P = 0.2341), whereas Group I showed a significant difference when compared with Group III (P = 0.0107). When the mean values of Group II and Group III were compared, the data were found to be statistically not significant (P = 0.0805).

Conclusion:

The efficacy of 2% CHX was found to be slightly superior when compared with that of 0.2% CTR, but the difference was not statistically significant. However, a significant difference was found between 2% CHX and combination irrigants.

A prospective cohort study evaluating the outcome of root canal retreatment in symptomatic mandibular first molars with periapical lesions

AIM

To evaluate the impact of various predictors on the outcome of root canal retreatment in symptomatic mandibular first molars with periapical lesions after a minimum of 2 years.

METHODOLOGY

One hundred and twenty previously root canal treated symptomatic mandibular first molars with periapical lesions which were diagnosed as symptomatic apical periodontitis or acute apical abscess with localized intraoral swelling were included. Root canal retreatment was performed by an experienced endodontist using a standardized treatment protocol. The teeth were followed up clinically and radiographically and the radiographic outcome was assessed using a modified periapical index scale (PAI). The cumulative success proportion and the influence of predictors on the outcome of the root canal retreatment were analysed using Kaplan-Meier analyses and log-rank tests, and the hazard ratios for the predictors were also investigated using Univariate Cox Proportional Hazard regression analysis at a significance level of 5%.

RESULTS

Of the 120 teeth, 103 teeth were re-examined with an 85% recall rate. The cumulative success rate was 88% in which 64% were healed and 24% were healing, and failure rate was recorded as 12%. None of the preoperative predictors, including age, gender, soft tissue tenderness, intraoral swelling, size of the lesion, PAI score, apical level and density of root canal filling before root canal retreatment, nor intraoperative predictors, such as active exudate drainage, density of root canal filling after root canal retreatment and restoration type had an influence on the outcome of root canal retreatment (p > .05). The only factor that significantly reduced the success rate of root canal retreatment was the apical level of the root canal filling; when it was more than 2 mm short of the radiographic apex in teeth where apical patency was not established, the success was significantly lower (p = .023).

CONCLUSIONS

Root canal retreatment in symptomatic mandibular first molars with periapical lesions resulted in a success rate of 88%. None of the predictors had a significant influence on the outcome, except for the apical level of the root canal filling after root canal retreatment with short root fillings being associated with significantly more post-treatment endodontic disease.

The influence of different NiTi instrumentation techniques on postoperative pain after single-visit root canal treatment

This study aimed to evaluate the effect of multi-file rotary (Protaper Universal) and reciprocating single-file (Reciproc Blue) root canal preparation techniques on the occurrence of postoperative pain in asymptomatic mandibular molar teeth with large periapical lesions in single-visit root canal treatment (RCT). A hundred and twenty teeth were randomly assigned to two groups: Protaper Universal (PTU) or Reciproc Blue (RB) instruments. Postoperative pain at 6, 12, 24, 48, 72 h and 7 days after obturation was measured. Mann-Whitney U-test was performed to compare the pain scores between the groups and to assess the relation of pain with patients' age and gender. Spearman's rank correlation was utilized to correlate the pain intensity and analgesic intake at different time points. There was no significant difference between the instrumentation techniques regarding postoperative pain at any time points evaluated (P > 0.05). There was a correlation between analgesic intake and intensity of pain (P < 0.05). No statistically significant difference was found among the groups assessed in the study in terms of analgesic intake (P > 0.05).

Current perspectives on dental adhesion: (3) Adhesion to intraradicular dentin: Concepts and applications

Adhesion science is one of the greatest contributions to restorative dentistry. Adhesion not only established the current principles of tissue preservation, but also allowed for the production of more hermetic and long-lasting restorations. Although adhesive strategies are routinely used in most clinical situations, adhesion to root dentin is still a major challenge. The presence of humidity together with less intertubular dentin are factors that limit the adhesive potential of root dentin. This situation is more unfavorable in endodontically treated teeth prepared for prefabricated or custom-made intraradicular posts; these procedures may alter the mechanical properties of teeth by modifying the viable dentin surface for adhesion. Also, contaminants deposited on the dentin surface are difficult to remove through conventional techniques. Moreover, root canal morphology has a very unfavorable C-factor, bringing undesirable effects resulting from polymerization contraction of resin-based materials. However, the differences between coronal and root dentin are not a barrier for dentin adhesion. Standardization of procedures and care during clinical steps are fundamental to the success of adhesion to coronal or intraradicular dentin. Thus, it is essential to know the anatomy of the root structure, the factors that interfere with intraradicular adhesion, as well as the current adhesive materials and techniques.

The influence of two forms of chlorhexidine on the accuracy of contemporary electronic apex locators

Background

Accurate determination of working length (WL) is crucial for the success of endodontic therapy. The aim of this study was to determine the influence of 2% chlorhexidine digluconate solution, 2% chlorhexidine digluconate gel and 2% hypochlorite solution on the accuracy of two devices: the Raypex 5 and the ApexDal.

Methods

Twenty-nine single-rooted human teeth were used in this study. The crowns were cut horizontally and embedded in an alginate mass. In each tooth, six endodontic measurements were made using two electronic apex locators (EALs): a Raypex 5 and an ApexDal. For each EAL, measurements were taken with the following products: 2% chlorhexidine solution (CHX-S group), 2% chlorhexidine gel (CHX-G group) and 2% NaOCl (NaOCl group). After performing an endodontic measurement, the endodontic instruments were stabilized with flow resin composite. Afterwards, the roots were removed from the alginate mass, and the apical one-third of each root was cut lengthways to recover the canal system. Last, the distance between the file tip and the apical foramen was measured under a microscope at 60 x magnification.

Results

Statistically significant differences were found between CHX-S and NaOCl and CHX-G and NaOCl, but no significant differences were detected between CHX-S and CHX-G during the testing of both devices. No statistically significant differences were observed between the Raypex 5 and ApexDal for all intracanal media tested.

Conclusion

The EALs Raypex 5 and ApexDal had higher accuracy in the anatomical foramen of the root containing chlorhexidine in the gel or in the solution form than in the canal containing sodium hypochlorite.

Alexidine versus chlorhexidine for endodontic irrigation with sodium hypochlorite

Objective:

The objective of this study was to chemically evaluate precipitate formation on irrigation by different concentrations of chlorhexidine (CHX) and alexidine (ALX) with sodium hypochlorite (NaOCl).

Materials and Methods:

Six test tubes were prepared with 1 ml of 4% NaOCl. One milliliter of 2%, 1%, 0.5%, and 0.25% ALX was added to the first four, and in the last two, 1 ml of 2% CHX and 0.2% CHX was added, respectively. Samples were observed for color changes or precipitates at multiple time intervals. All solutions were then centrifuged at 1000 rpm for 10 min and re-examined for precipitates. This process was repeated twice. Fifty freshly extracted premolars were biomechanically prepared, dried, divided into two groups, and irrigated with 10 ml of 4% NaOCl and 10 ml of 2% ALX (Group 1) and 10 ml of 4% NaOCl and 10 ml of 2% CHX (Group 2). These samples were sectioned and observed for precipitates on the dentinal surfaces by scanning electron microscopy (SEM).

Results:

The color of the solution of ALX and NaOCl stayed transparent and no precipitate was observed. A color change was noted immediately on mixing CHX and NaOCl which did not change with time. Precipitates were only observed in the solutions of CHX with NaOCl and after centrifuging them. SEM views also showed dense precipitates covering the dentinal surface and occluding the dentinal tubules in Group 2.

Conclusion:

The interaction of ALX and NaOCl does not produce precipitates which together with its better antimicrobial action make ALX a more effective and safer replacement for CHX as an adjunctive endodontic irrigant.

The inhibitory effect of quaternary ammonium salt on bacteria in root canal

Persisting apical periodontitis is a primary reason for multiple intervention in root canal. Persisting bacteria in root canal is related with the persisting infection. Despite the advancement in treatment strategies the persisting infection is a major challenge for endodontist. Here we tested two newly developed quaternary ammonium methacrylates (QAMs) against endodontic bacteria and their biofilms. Their antibacterial and antibiofilm efficiency were compared with chlorhexidine (CHX) and sodium hypochlorite (NaOCl). We measured the MIC, MBC and MBIC of DMADDM and DMAHDM respectively. We also detected the ratio of live/dead bacteria and bacterial composition in the biofilms treated by DMADDM and DMAHDM. We found that DMADDM and DMAHDM could inhibit the growth of bacteria and biofilms formation. The result showed that novel QAMs were remarkably efficient than CHX against biofilms. In addition, we found that Streptococcus gordonii (S. gordonii) and Enterococcus faecalis (E. faecalis) were frequent isolates after treatment with antimicrobial compounds.

Assessment of Postoperative Pain Using Different Root Canal Irrigants in Mandibular Molars with Symptomatic Irreversible Pulpitis: An Observational Study

Background:

The present study was conducted to assess postoperative pain using different root canal irrigants in mandibular molars with symptomatic irreversible pulpitis.

Materials and methods:

The present study was conducted on 84 patients (40 males and 44 females) having 126 mandibular molars with symptomatic irreversible pulpitis. In all molars, access cavity preparation was done and the root canal shaping procedures were performed according to the manufacturer’s instructions for each instrument system. Teeth were divided into 2 groups. In Group I, the 5.25% sodium hypochlorite (NaOCl) solution was used as an irrigating solution. In Group II, the 2% chlorhexidine gluconate (CHX) was used as an irrigating solution. A visual analog scale (VAS) was used to assess postobturation pain on the 1st, 3rd, and 7th days.

Results:

There were 40 males and 44 females in the present study. In Group I, the 5.25% NaOCl solution was used as an irrigating solution. In Group II, the 2% CHX was used as an irrigating solution. Each group had 63 teeth. VAS was 9 in Group I and 8 in Group II on Day 1; 5 and 3 in Groups I and II, respectively, on Day 3; and 3 and 1 on Day 7 in Groups I and II, respectively. The difference was significant ( P < .05).

Conclusions:

There were excellent results obtained with the 2% CHX solution as compared with the 5.25% NaOCl solution. Group II exhibited less VAS than Group I.

Unprepared root canal surface areas: causes, clinical implications, and therapeutic strategies

Chemomechanical preparation is intended to clean, disinfect, and shape the root canal. This step is of utmost importance during treatment of infected teeth with apical periodontitis, because treatment outcome depends on how effectively the clinician eliminates bacteria, their products, and necrotic tissue that would serve as substrate for bacterial regrowth. Nonetheless, curvatures and complex internal anatomical variations of the root canal system can pose a high degree of difficulty in reaching these goals. In infected teeth, bacteria may persist not only in difficult-to-reach areas such as isthmuses, ramifications, dentinal tubules, and recesses from C-shaped or oval/flattened canals, but also in areas of the main canal wall that remain untouched by instruments. If bacteria withstand chemomechanical procedures, there is an augmented risk for post-treatment apical periodontitis. This article discloses the reasons why some areas remain unprepared by instruments and discusses strategies to circumvent this issue and enhance infection control during endodontic treatment/retreatment of teeth with apical periodontitis.

Efficacy of chlorhexidine as a final irrigant in one-visit root canal treatment: a prospective comparative study

AIM

To evaluate postoperative pain and radiographic evidence of periapical healing in teeth with apical periodontitis treated in one visit with an additional final irrigation using 2% chlorhexidine (CHX) and to compare the results with conventional two-visit root canal treatment (RCT) with an intracanal calcium hydroxide (CH) dressing as a control group.

METHODOLOGY

Ninety asymptomatic maxillary anterior teeth with periapical lesions were treated by a single operator. Root canals were prepared using the step-back technique with manual instrumentation with 2.5% NaOCl and 5% EDTA as irrigants. Half of the teeth were randomly assigned to the one-visit (OV) group and received an additional final rinse with 2% CHX before canal filling. The other teeth were treated in two visits (TV) with a CH paste made by mixing CH powder and distilled water as an interappointment dressing. All patients were recalled and investigated clinically and radiographically for 24 months. Postoperative pain at 24-48 h and changes in apical bone density indicating radiographic healing were evaluated statistically using the Mann-Whitney U-test followed by the Friedman and the Wilcoxon tests (α = 0.05).

RESULTS

There were no significant differences between two groups regarding the incidence of postoperative pain at 24 h (OV group 50% no pain, 47.6% mild, 2.4% moderate pain/TV group 55% no pain, 42.5% mild, 2.5% moderate pain) and at 48 h (OV group 95% no pain, 5% mild pain/TV group 98% no pain, 2% mild pain). None of the patients reported severe postoperative pain, swelling and/or flare-ups during the follow-up period. There was no significant difference in the radiographic healing rates (OV group 97.6% PAI 1 and/or PAI 2 and 2.4% PAI 3/TV group 95% PAI 1 and/or PAI 2 and 5% PAI 3; P > 0.05).

CONCLUSION

Both groups provided favourable and similar postoperative pain and periapical healing rates at 24 months. Thus, one-visit RCT with a final rinse with 2% CHX is an acceptable alternative to two-visit RCT with CH as temporary dressing in maxillary anterior teeth.

Determination of the Minimum Inhibitory Concentrations of Alexidine and Chlorhexidine Against Enterococcus faecalis and Candida albicans: An In Vitro Study

Introduction: The root canal system must be mechanically instrumented and chemically cleaned using various antimicrobial irrigants in a sequential manner or in combination for the elimination of necrotic pulp tissue and reducing the number of root canal bacteria. For this reason, new methods and materials are continuously being developed to achieve the objectives of endodontic treatment.

Materials and Methods: E. faecalis (ATCC 29212) and C. albicans (ATCC 90028) standard strains were used for this study. Colonies of E. faecalis and C. albicans were harvested from the agar plates and suspended in 4 mL of phosphate buffered saline (PBS). Microorganisms were diluted to obtain a suspension of approximately 108 colony-forming units/mL (CFU/mL) in sterile PBS using McFarland standard tubes no. 0.5.

Results: After a two-minute contact time, all alexidine (ALX) concentrations used in this study eradicated all E. faecalis strains, while chlorhexidine (CHX) didn’t kill 100% of E. faecalis at 0.25% and lower concentrations even after a five-minute contact time. ALX also eradicated C. albicans at all concentrations even after a one-minute contact time. CHX showed antifungal activity against C. albicans at all concentrations higher than 0.031% after a one-minute contact time.

Conclusion: A 0.0156% concentration of ALX can be a good alternative to CHX as an irrigation solution in endodontic treatment when used for one minute against E. faecalis and C. albicans.

Contemporary Cleaning and Shaping of the Root Canal System

Prevention or treatment of apical periodontitis is aimed at disinfecting the root canal system so that the periradicular tissues are not vulnerable to attack from microbiota within the tooth. This is achieved by a process of cleaning and shaping the root canal space. The fundamental principles underlying this process have not changed in decades. In contrast, the armamentarium available to the clinician continues to evolve rapidly. The use of specially designed nickel titanium (NiTi) files to create a glidepath allows the clinician to manage tight curved canals more predictably in situations which would otherwise have proved too difficult using conventional techniques. Other files, designed to shape the canal, have been developed using metallurgic principles which permit NiTi files to be more flexible and resistant to cyclic fatigue. These newer systems also require fewer instruments to prepare a canal and some, which have adopted a reciprocating (rotational) motion, may only require one file. Progress is also being made in enhancing efficacy of irrigant activity using negative apical pressure systems, sonic and ultrasonic agitation techniques. These contemporary techniques used to clean and shape the root canal system should result in improved confidence and predictability when managing endodontic disease.

Análise de dois métodos de desinfecção de condutos radiculares após preparo para pinos: proposta de protocolo protético: estudo in vitro

Resumo Introdução Quando existe perda de suporte coronário e ainda desgaste adicional devido a tratamento endodôntico, muitas vezes, é necessária a utilização de um retentor intrarradicular que devolva a retenção para a restauração, reestabelecendo estética e função às estruturas dentárias perdidas. A cadeia asséptica mantida durante a endodontia pode ser quebrada com alguns procedimentos clínicos. Objetivo Testar um protocolo de desinfecção por E. faecalis dos condutos radiculares, nas etapas de confecção de um retentor intrarradicular, desmistificando que a quebra da cadeia asséptica e o surgimento de infecções radiculares sejam provenientes da reabilitação protética. Material e método 50 dentes unirradiculares com endodontia concluída foram desobturados, tiveram seus condutos preparados para retentor intrarradicular e foram contaminados por Enterococcus faecalis. Os dentes foram separados em três grupos de acordo com a substância desinfectante: G1-solução fisiológica (n=10), G2- hipoclorito de sódio 2,5% (n=20), G3- clorexidina 2% (n=20). Em seguida, foi feita a desinfecção do conduto, secagem e análise da eficácia da solução. A avaliação da presença da bactéria foi feita através do cultivo em caldo Brain Heart Infusion, pelo método da turvação, e posterior identificação pelo meio Ágar Bílis-Esculina. A análise estatística foi feita pelo método do quiquadrado em tabulação cruzada, onde p<0,0001. Resultado Observou-se a inibição bacteriana de 100% em G2 e G3 e crescimento bacteriano de 100% em G1. Conclusão O emprego das substâncias avaliadas nas etapas protéticas de finalização de um retentor intrarradicular, como protocolado por esta pesquisa, é capaz de manter a cadeia asséptica sem interferir no sucesso da reabilitação protética.

Antimicrobial efficacy of chlorhexidine as a root canal irrigant: a literature review

Use of an appropriate root canal irrigant is essential during endodontic treatment, due to the complex and unpredictable anatomy of the root canal system and limitations in the mechanical instrumentation techniques used to obtain a clean, bacteria-free canal. Several irrigants, such as sodium hypochlorite, chlorhexidine, hydrogen peroxide, and normal saline, have been proposed as canal system irrigants in endodontic treatment. The widely used endodontic irrigant chlorhexidine is a positively charged lipophilic/hydrophobic molecule that interacts with phospholipids and lipopolysaccharides on the bacterial cell membrane. In endodontics, its mode of antibacterial activity is determined by its concentration (0.2% or 2%). This article reviews findings from available endodontic studies on the antibacterial, antifungal, and antibiofilm activities of chlorhexidine.

Antibacterial efficacy of Azadirachta indica, Mimusops elengi and 2% CHX on multispecies dentinal biofilm

Aims:

To check the antimicrobial activity of Azadirachta indica (Neem), Mimusops elengi (Bakul), and Chlorhexidine gluconate (CHX) on multispecies biofilm of common endodontic pathogens such as Streptococcus mutans, Enterococcus faecalis, Staphylococcus aureus and Candida albicans.

Settings and Design:

In vitro dentin disinfection model used to check the antimicrobial efficacy of herbal extracts.

Materials and Methods:

The in vitro dentin disinfection model was used to check the antimicrobial activity of the methanolic extracts of the medicinal plants along with Chlorhexidine gluconate. The polymicrobial biofilm was allowed to grow on extracted teeth sections for a period of 21 days. Remaining microbial load in the form of CFU/ml after the antimicrobial treatment was tabulated, and data were statistically analyzed using ANOVA and Bonferroni post-hoc tests.

Statistical Analysis Used:

SPSS version 17, one-way ANOVA, Bonferroni post-hoc test.

Results:

Both the plant extracts showed considerable antimicrobial efficacy as compared to negative control. 2% CHX was the most effective antimicrobial agent having statistically significant difference against plant extracts and negative control (saline).

Conclusion:

The methanolic extract of A. Indica, M. elengi, and Chlorhexidine Gluconate has considerable antimicrobial activity against polymicrobial dentinal biofilm of S. mutans, E. faecalis, S. aureus and C. albicans.

Comparative evaluation of effect of different irrigation solutions against Enterococcus faecalis: A polymerase chain reaction-based study

Enterococcus faecalis is the most isolated or detected species from oral infections including marginal periodontitis, infected root canals, periradicular abscesses and also detected in cases of failed endodontic therapy. To prevent endodontic treatment failure irrigation is mandatory for the effective removal of smear layer, pulp tissue, and microorganisms. Cultivation and other traditional identification methods have been demonstrated to have several limitations when it comes to microbiological identification. Polymerase chain reaction was selected because it has an added advantage over traditional microbiological methods.

Analysis of the reaction of subcutaneous tissues in rats and the antimicrobial activity of calcium hydroxide paste used in association with different substances

The aim of this study was to evaluate the subcutaneous tissue response in rats and the antimicrobial activity of intracanal calcium hydroxide dressings mixed with different substances against E. faecalis. Fifty four rats were divided into three experimental groups according to the vehicle in the calcium hydroxide treatment: 0.4% chlorohexidine in propylene glycol (PG), Casearia sylvestris Sw in PG and calcium hydroxide+PG (control group). The pastes were placed into polyethylene tubes and implanted into the subcutaneous tissue. After 7, 14 and 30 days, the samples were processed and histologically evaluated (hematoxylin and eosin). The tissue surface in contact with the material was analyzed, and the quantitative analysis determined the volume density occupied by the inflammatory infiltrate (giant cells, polymorphonuclear cells and mononuclear cells), fibroblasts, collagen fibers and blood vessels. For the antimicrobial analysis, 20 dentin blocks infected with E. faecalis were treated with calcium hydroxide pastes in different vehicles; 0.4% chlorhexidine in PG, PG, extract from Casearia sylvestris Sw in PG and a positive control (infection and without medication) for 7 days. The efficiency of the pastes was evaluated by the live/dead technique and confocal microscopy. The results showed that 0.4% chlorhexidine induced a higher inflammatory response than the other groups. The Casearia sylvestris Sw extract showed satisfactory results in relation to the intensity of the inflammatory response. In the microbiological test, there were no statistical differences between the evaluated intracanal dressings and the percentage of bacterial viability was between 33 and 42%. The control group showed an 86% viability. Antimicrobial components such as chlorhexidine or Casearia sylvestris Sw did not improve the antimicrobial activity against E. faecalis in comparison to the calcium hydroxide+PG treatment. In addition, the incorporation of chlorhexidine in the calcium hydroxide paste promoted the highest inflammatory response.

Cytotoxicity of a novel nano-silver particle endodontic irrigant

Purpose

The aim of this study was to evaluate the cytotoxic effect of a novel nano-silver particle (25.2±6.5 nm) endodontic irrigant (0.2 mM) and compare it with 3% sodium hypochlorite.

Materials and methods

Two cell types, mouse fibroblast National Institutes of Health 3T3 (NIH 3T3) and primary human periodontal ligament stem cell (hPDLSCs) were used in a test for the effect of direct and indirect (by separating the agent and cell with a layer of agar) exposure to the two solutions. In the direct exposure experiment, ten groups of cell cultures were exposed to one dilution (3:1, 2:1, 1:1, 1:2, 1:3, 1:4, 1:5, 1:6 or 1:7) of a nano-silver irrigant for 48 hours; the concentration-response function was estimated by determining the number of viable cells in each group by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The 50% lethal dose of the testing irrigant for NIH3T3 and hPDLSCs were estimated. In the second part of the experiment, a modified agar overlaying technique was applied. Twelve culture wells (6-well plate) were divided into three groups (n=4). The cell lysis zone (cytotoxic range) created by the stock nano-silver solution, 3% sodium hypochlorite, and an isotonic phosphate buffering saline (control) was measured by two double blinded observers (Kappa score =100%). The cytotoxic score of specific irrigant was derived by modified Sjögren’s method.

Results

The 50% lethal doses of the testing nano silver irrigant for NIH 3T3 and hPDLSCs after 48 hours of direct exposure were 0.58 and 0.608 dilution of stock solution, respectively. The cytotoxic scores of nano-silver irrigant and control (phosphate buffered saline) on NIH 3T3 were 0.25 (95% confidence interval [CI] =0 to 1.04) and 0 (95% CI =0 to 0); and on hPDLSCs were 0.13 (95% CI =0 to 0.52) and 0.25 (95% CI =0 to 1.04), respectively. Toxicity of the test and control group on both mouse fibroblasts (P>0.05) and hPDLSCs (P=1.00) was not statistically different.

Conclusion

Our results showed that the nano-silver irrigant was non-cytotoxic to both NIH 3T3 and hPDLSCs.

Biofilm in endodontics: A review

Endodontic disease is a biofilm-mediated infection, and primary aim in the management of endodontic disease is the elimination of bacterial biofilm from the root canal system. The most common endodontic infection is caused by the surface-associated growth of microorganisms. It is important to apply the biofilm concept to endodontic microbiology to understand the pathogenic potential of the root canal microbiota as well as to form the basis for new approaches for disinfection. It is foremost to understand how the biofilm formed by root canal bacteria resists endodontic treatment measures. Bacterial etiology has been confirmed for common oral diseases such as caries and periodontal and endodontic infections. Bacteria causing these diseases are organized in biofilm structures, which are complex microbial communities composed of a great variety of bacteria with different ecological requirements and pathogenic potential. The biofilm community not only gives bacteria effective protection against the host's defense system but also makes them more resistant to a variety of disinfecting agents used as oral hygiene products or in the treatment of infections. Successful treatment of these diseases depends on biofilm removal as well as effective killing of biofilm bacteria. So, the fundamental to maintain oral health and prevent dental caries, gingivitis, and periodontitis is to control the oral biofilms. From these aspects, the formation of biofilms carries particular clinical significance because not only host defense mechanisms but also therapeutic efforts including chemical and mechanical antimicrobial treatment measures have the most difficult task of dealing with organisms that are gathered in a biofilm. The aim of this article was to review the mechanisms of biofilms’ formation, their roles in pulpal and periapical pathosis, the different types of biofilms, the factors influencing biofilm formation, the mechanisms of their antimicrobial resistance, techniques to identify biofilms.

Determination of chemical components derived from 2% chlorhexidine gel degradation using gas chromatography-mass spectrometry

OBJECTIVE

This study determined the chemical components derived from degradation of 2% chlorhexidine (CHX) gel and solution by using gas chromatography-mass spectrometry.

MATERIALS AND METHODS

Three 2% CHX gels were used to identify the products of CHX gel degradation using gas chromatography-mass spectrometry. A solution of CHX was also evaluated to compare the degradation between gel and solution. Degradation was evaluated in four storage situations (on the worktable with light: on the worktable without light; in the Pasteur oven at 36.5°C without light; and in the refrigerator at 8°C without light). Measurements were made at four time points: initial analysis and 1, 3 and 6 months after. The conversion of CHX into para-chloroaniline in storage situations and in different periods was analyzed statistically using chi-square test (α = 5%).

RESULTS

The 2% CHX gel or solution had already degraded vial found within the period of validity, at all time points and for all storage conditions. The amount of para-chloroaniline (pCA) was directly proportional to time in the case of CHX solution, but not in CHX gel due to lack of homogeneity. CHX homogeneity in hydroxyethylcellulose gel was directly dependent on compounding mode.

CONCLUSIONS

Degradation products, such as para-chloroaniline (pCA), orto- chloroaniline (oCA), meta-chloroaniline (mCA), reactive oxygen species (ROS) and organochlorines (ortho-chlorophenyl isocyanate and 2-amino-5-clorobenzonitrila) were found in 2% CHX gel and solution, regardless of storage conditions or time. In relationship to gel homogenization an alternative to produce 2% CHX gel and a new homogenization method have been developed.

Quantitative and qualitative analysis of microorganisms in root-filled teeth with persistent infection: Monitoring of the endodontic retreatment

Objective:

The aim of this study was to investigate in vivo microorganisms detected in root-filled teeth with post-treatment apical periodontitis and quantify colony-forming units (CFU) during endodontic retreatment.

Materials and Methods:

Fifteen root-filled teeth had their previous gutta-percha removed and were randomly instrumented before being divided into three groups and medicated with either [Ca(OH)₂ + 2% CHX gel], [Ca(OH)₂ + 0.9% NaCl] or 2% CHX gel. Samples were taken after removal of gutta-percha (S1), after chemomechanical preparation using 2% CHX gel (S2), and after inter-appointment dressing (S3) for 7 or 14 days later. Cultivable bacteria recovered from infected root canals at the three stages were counted and identified by means of culture and PCR assay (16S rDNA). Quantitative data were statistically analyzed by using Mann-Whitney test in which pairs of groups were compared (P < 0.05).

Results:

CFU counts decreased significantly from S1 to S2 (P < 0.05). No significant difference was found between S2 and S3 (P = 0.3093) for all three experimental groups. Chemomechanical preparation and intra-canal dressing promoted significant median reductions of 99.61% and 99.57%, respectively, in the number of bacteria compared to S1 samples. A total of 110 cultivable isolates were recovered by culture technique from 32 different species and 7 different genera. Out of the 13 target species-specific primer of bacteria analyzed, 11 were detected during endodontic retreatment.

Conclusion:

The great majority of taxa found in post-treatment samples were Gram-positive bacteria, although Gram-negative bacteria were found by molecular methods. Moreover, our results showed that gutta-percha removal and chemomechanical preparation are effective for root canal disinfection, whereas additional intra-canal dressing did not improve disinfection.

Cytotoxicity of QMix™ endodontic irrigating solution on human bone marrow mesenchymal stem cells

Background

Debridement and disinfection of the root canal system is a crucial step in endodontic procedures. The effectiveness of irrigation relies on both the mechanical flushing action and the ability of irrigants to dissolve tissue and kill bacteria. The objective of the present study is to evaluate and compare the cytotoxicity of QMix™ root canal irrigating solution on immortalized human bone marrow mesenchymal stem cells (hTERT-MSC-C1) and to compare it with that of sodium hypochlorite (NaOCl).

Methods

Immortalized human bone marrow mesenchymal stem cells (hTERT-MSCs) were exposed to QMix™ and NaOCl. Cell viability was assessed by 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and alamarBlue assays. The cell morphology was studied after two hours of exposure to QMix™ and NaOCl. Scanning electron microscopy (SEM) analyses were performed after 2- and 4-hour incubation periods. Finally, ethidium bromide/acridine orange (EB/AO) fluorescent stain was applied to the cells in the 8-chamber slides after they were incubated with the testing agents for 2 hours to detect live and dead cells. The observations were tabulated and analyzed statistically.

Results

QMix™ exposure resulted in a significantly higher percentage of cell viability than NaOCl in the MTT and alamarBlue assays at three time points compared to the control. The SEM analysis demonstrated minimal morphological changes associated with cells that were exposed to the QMix™ solution, with little shrinkage and fragmentation of the cell wall. The live/dead analysis showed that the number of live cells after exposure to QMix™ was similar to that of the untreated control. No cell structure could be observed with the NaOCl group, indicating cell lysis.

Conclusion

Both the QMix™ and NaOCl solutions were toxic to human bone marrow MSCs. Each solution might have induced cell death in a different way as evidenced in the cell viability, SEM and fluorescent studies. The slower cell death induced by QMix™ might therefore be less aggressive and more acceptable to living tissues.

Various irrigation protocols for final rinse to improve bond strengths of fiber posts inside the root canal

Irrigation after post space preparation and its effects on the bond strength of different adhesive strategies are still an issue of interest. The aim of the present study was to investigate the effects of various irrigation protocols (IPs) on the push-out bond strengths of fiber posts. One-hundred and fifty extracted human anterior teeth were divided into three groups (n = 50 each) and endodontically treated. The post space was irrigated before post placement using the following five IPs in each group: IP1 (control): 5 ml of distilled water; IP2: 5.25% sodium hypochlorite (NaOCl) applied with passive ultrasonic irrigation (PUI); IP3: 1% NaOCl applied with PUI; IP4: 18% ethylenediaminetetracetic acid (EDTA) followed by 5.25% NaOCl; and IP5: 2% chlorhexidine (CHX). Fiber posts placement in each group was performed using three different adhesive strategies. A self-etch adhesive system revealed higher bond strength (16.2 ± 6.9 MPa) compared with an etch-and-rinse adhesive (8.5 ± 4.2 MPa) and a self-adhesive resin cement (9.2 ± 4.7 MPa). The use of 18% EDTA/5.25% NaOCl increased the bond strength of the self-adhesive resin cement. Conversely, this IP decreased the bond strength for the etch-and-rinse adhesive system, whilst 1% NaOCl enhanced the bond strength for the same system. Consequently, each adhesive strategy may need to be adapted to a specific IP.

Evaluation of the sealing ability of two sealers after using chlorhexidine as a final irrigant: An in vitro study

Aims and Objectives:

The aim of this study was to evaluate the effect of the precipitate formed by using sodium hypochlorite and chlorhexidine as a root canal irrigant on the sealing ability of different root canal sealers, using a push-out bond strength test.

Materials and Methods:

Twenty single rooted premolars were used for this study. The teeth were divided into two groups (Groups I and II) of ten teeth each, according to the obturation done with AH Plus with GuttaPercha and Resilon with epiphany, respectively. The groups were in turn divided into two subgroups of five teeth each (Subgroups A and B) according to the irrigation protocol, and were evaluated using a micro push-out bond strength, with the help of a universal testing machine. Statistical analysis was done using the paired t test.

Results:

The mean value of the AH Plus GuttaPercha group with precipitate formation (17.66 ± 0.56) showed the highest mean value for the bond strength, which was statistically higher (P < 0.05) than the rest of the groups. In the Resilon Epiphany group, the samples with precipitate formation showed (13.28 ± 1.35) the least bond strength, which was statistically lower than all the groups, except the Resilon samples without precipitate (13.99 ± 0.48).

Conclusion:

The precipitate formed by a combination of sodium hypochlorite and chlorhexidine tends to affect the bond strength of the sealers used for obturation.

Effect of endodontic irrigation and dressing procedures on the shear bond strength of composite to coronal dentin

This study aimed to evaluate the effects of three sodium hypochlorite (NaOCl)-endodontic irrigation procedures used alone or in combinations with two intermediate dressing materials on bond strengths of two adhesive composite systems to coronal dentin. Surfaces were treated with NaOCl or NaOCl–Glyde-File-Prep (H₂O₂ and EDTA) with or without chlorhexidine (CHX) as a final rinse. Intermediate dressing materials of calcium hydroxide (Ca(OH)₂) and sodium perborate (SP) were combined with surface treatments. Surface treatment groups (n = 10/group) included (1) distilled water (control), (2) 5.25% NaOCl (30 min), (3) NaOCl/Glyde (30 min), (4) NaOCl/Glyde (30 min) + CHX (2 min), (5) NaOCl/Glyde (30 min) + Ca(OH)₂ (5 days) + CHX (2 min), and (6) NaOCl/Glyde (30 min) + SP (9 days) + CHX (2 min). For each surface treatment group, dentin shear bond strengths of two different composite systems (Excite/Tetric Flow Chroma, [EX/TFC], and Clearfil Protect Bond/Protect Liner F [PB/PLF]) were evaluated. Median shear bond strengths (EX/TFC, PB/PLF) for each surface treatment group in MPa were (1) 21, 18; (2) 26, 18; (3) 21, 17; (4) 22, 16; (5) 17, 11; and (6) 14, 11, respectively. NaOCl significantly increased the bond strength of EX/TFC (p < 0.05), but did not significantly affect that of PB/PLF. The use of NaOCl/Glyde with CHX did not significantly affect EX/TFC (p > 0.05), whereas it significantly decreased PB/PLF (p < 0.05). Ca(OH)₂ and SP significantly decreased the bond strengths of both adhesive systems (p < 0.05). Adhesion to coronal dentin is dependent upon the irrigation regimen and the type of adhesive.

Radiology in practice: a case study

The dentures are aesthetically pleasing and the patient is very happy with the outcome (figures 27-28). The improved retention from the precision attachments has stabilised the lower denture very effectively and has allowed the patient to adapt well to wearing a lower complete denture. In combination with a thorough clinical examination, the appropriate use of radiographs and other special tests are essential for both planning and treating a restorative case.

The effects of various irrigating solutions on intra-radicular dentinal surface: An SEM analysis

Aim:

The action of irrigant solutions on intra- radicular dentinal surface were evaluated in an in vitro setting using a scanning electron microscope (SEM) and it was observed that sodium hypochlorite and MTAD produced the cleanest surface and that none of the irrigants were able to produce an ideal preparation of the dentinal surface when used individually. The primary objective of endodontic therapy is to achieve a clean, optimal environment in root canals to avoid unsuccessful treatment outcomes. The complexities of the root canal system necessitate the use of irrigating solutions which act on radicular dentin surface, modifying it. The action of irrigants can be beneficial, and yet at the same time, as they modify the surface structure of dentin, they can have an adverse impact on the properties of dentin. The present study was undertaken to assess the effect of various irrigants on the dentinal surface using an SEM.

Materials and Methods:

Forty-five roots were randomly divided into nine groups (n=5) and prepared by sectioning at the level of cemento-enamel junction (CEJ) and 10 mm from the CEJ and split longitudinally. The dentin surface was prepared and the cemental surfaces were coated with double layer of varnish. The irrigants tested were normal saline, de-ionized water, 17% ethylenediaminetetraacetic acid (EDTA), 5% sodium hypochlorite (NaOCl), 5% NaOCl with ultrasonic agitation, 3% hydrogen peroxide, 2% chlorhexidine (CHX), MTAD, and MTAD with ultrasonic agitation. The prepared samples were placed in the irrigant solution for 3 min, subsequently dehydrated, sputter coated, and observed under SEM. The images were subsequently analyzed for dentinal surface changes.

Results:

17% EDTA and MTAD produced the cleanest dentinal surface. Ultrasonic agitation enhanced the effect of irrigants. 5% NaOCl and 3% hydrogen peroxide were efficient at removal of organic debris, but were unable to remove the smear layer. De-ionized water, normal saline, and 2% chlorhexidine were not effective at removing the debris or the smear layer.

Conclusion:

None of the irrigants individually were able to achieve conditions of an ideal dentinal surface preparation.

Irrigants for non-surgical root canal treatment in mature permanent teeth

BACKGROUND

Root canal treatment is carried out on teeth in which irreversible pulpitis has led to necrosis of the dental pulp. As a treatment option it is an alternative to dental extraction. Mechanical preparation and irrigation with antiseptic or antibacterial solutions destroys bacteria and cleans the infected root canal. Irrigants should be effective in deactivating bacteria in the entire root canal space without causing any adverse tissue reactions. Sodium hypochlorite (NaOCl) and chlorhexidine are commonly used but there is uncertainty as to which solution, concentration or combination is the most effective.

OBJECTIVES

To assess the effects of irrigants used in the non-surgical root canal treatment of mature permanent teeth.

SEARCH METHODS

We searched the Cochrane Oral Health Group's Trials Register (to 5 July 2012), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2012, Issue 4), MEDLINE via Ovid (1950 to 5 July 2012), EMBASE via Ovid (1980 to 5 July 2012), LILACS via BIREME (1980 to 5 July 2012). There were no restrictions regarding language or date of publication.

SELECTION CRITERIA

Randomised controlled trials in single or multi-rooted permanent teeth with pulpal or periapical pathology or both, which require root canal treatment. Irrigants either against each other or against inactive irrigant or placebo. Combinations of irrigants were allowed and if used in conjunction with EDTA (ethylenediaminetetra-acetic acid) or similar chelating agents.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed risk of bias of included trials and extracted data.

MAIN RESULTS

We included 11 trials involving 851 participants with 879 teeth which had undergone root canal treatment and involved the use of irrigants. Two trials were assessed as being at low risk of bias, with six unclear and three high. Four trials compared sodium hypochlorite versus chlorhexidine, however, no primary outcomes and only one secondary outcome, bacterial growth cultures, was reported for two of these trials (20% and 50% of teeth in the control group had positive bacterial culture). The meta-analysis indicated no strong evidence of a difference in the existence of bacterial growth between the interventions (risk ratio 0.73; 95% confidence interval 0.34 to 1.56; P = 0.41). The seven remaining trials each compared different interventions and only two of these trials included useable data on the primary outcomes of swelling and pain. One trial compared sodium hypochlorite 5.25% alone versus sodium hypochlorite 5.25% combined with hydrogen peroxide 3%, and versus normal saline and reported pain at 3 to 14 days after the procedure. There was no evidence of a difference in pain between the three groups. The other trial compared sodium hypochlorite 5% versus sodium hypochlorite with 'proteolytic enzyme', and there was no evidence of a difference in swelling between the groups. Two further trials reported bacterial growth, and three trials failed to report any data which could be used in the review. None of the included trials reported any data on adverse effects nor radiological changes in periapical radiolucency.

AUTHORS' CONCLUSIONS

Although root canal irrigants such as sodium hypochlorite and chlorhexidine appear to be effective at reducing bacterial cultures when compared to saline, most of the studies included in this review failed to adequately report these clinically important and potentially patient-relevant outcomes. There is currently insufficient reliable evidence showing the superiority of any one individual irrigant. The strength and reliability of the supporting evidence was variable and clinicians should be aware that changes in bacterial counts or pain in the early postoperative period may not be accurate indicators of long-term success. Future trials should report both clinician-relevant and patient-preferred outcomes at clearly defined perioperative, as well as long-term, time points.

Endodontic 'solutions' part 1: a literature review on the use of endodontic lubricants, irrigants and medicaments

Endodontic lubricants, irrigants and medicaments help prepare and disinfect root canal systems (RCS) but primary and secondary cases involve different microbes and therefore it is unlikely that one protocol will be effective for both case types. Each individual 'solution' or sequence of'solutions' could play a significant role in each case type, but there are no detailed published guidelines in existence. To help inform clinical practice it was decided to undertake a literature review followed by a UK and Republic of Ireland wide audit on current endodontic'solution' usage within dental schools. The literature review was undertaken under the following headings: pre-op oral rinse; file lubricants; root canal irrigants and intracanal medicaments and provides an evidence base for protocol development for both primary and retreatment cases.The audit project and the protocols developed from the findings of both the literature review and audit will be presented in Part 2.

Non-surgical endodontics in retreatment of periapical lesions - two representative case reports

This article reports non-surgical endodontic retreatment of two patients with persistent or recurrent periapical lesions, who had previously undergone surgical and non-surgical endodontic therapy respectively. It further discusses and reviews the relevance of classification of periapical lesions, the explanation behind healing of periapical lesions by endodontic therapy alone, causes of persistence of periapical lesions, choice of treatment modalities (whether surgical or non - surgical) and materials such as intracanal medicaments and irrigants for optimal healing. Key words:Non-surgical, retreatment, periapical, calcium hydroxide, chlorhexidine irrigation.

Comparative study of the antimicrobial effect of three irrigant solutions (chlorhexidine, sodium hypochlorite and chlorhexidinated MUMS)

AIM

To compare the antimicrobial effect of 2% chlorhexidine, 2.5% sodium hypochlorite and MUMS containing 2% chlorhexidine.

MATERIALS AND METHODS

All of the above irrigants were examined on Enterococcus faecalis, Streptococcus mutans, Candida albicans, Lactobacillus casei and E. coli. A total of 0.5 CC of each solution and 0.5 CC of McFarland solution bacterium were added to each examination tube. After 15, 30 and 45 minutes, colony count was performed for each tube. The difference in the number of bacteria indicated the effect taken by disinfectant material.

RESULTS

MUMS containing chlorhexidine showed the antimicrobial properties just like chlorhexidine's effect against E. coli, Streptococcus mutans, Candida albicans, Enterococcus faecalis and Lactobacillus casei in preventing these entire microorganisms to incubate. Sodium hypochlorite was not effective against Enterococcus faecalis and Candida albicans incubated in 15, 30 and 45 minutes and Enterococcus faecalis in 15 minutes.

CONCLUSION

MUMS has antimicrobial properties similar to chlorhexidine.

CLINICAL SIGNIFICANCE

As MUMS containing chlorhexidine can transfer chlorhexidine through its own surfactant around apical area and it can open the dentinal tubules by its own chelator for more penetration of chlorhexidine, it may be a choice for canal irrigation.