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This is a series of 7 cases in which the operator penetrated lateral canals with instruments. Two teeth presented with irreversible pulpitis, 4 with necrotic pulps, and 1 with previous treatment. Except for the teeth with pulpitis, all the others were associated with apical periodontitis. The main root canal was always relatively straight, with the lateral canals at the middle third of the root. Suggestive images of lateral canal presence were seen on periapical radiographs in five cases. The clinician introduced intentionally small hand instruments in the lateral canal in 5 cases, while the penetration was fortuitous in the others. The lateral canals were obturated in all cases. Follow-up examination was possible in five cases, all of them showed evidence of successful clinical and radiographic outcomes. Introducing files into lateral canals may permit some preparation and penetration of irrigant solution, favoring disinfection and, consequently, enhancing the treatment outcome. (EEJ-2023-05-063).

Aim: To analyse the effect of ultrasonic irrigant activation (UIA) and the GentleWave (GW) multisonic irrigation (GW) with minimal instrumentation on the root canal microbial diversity in an ex vivo model that used extracted molars with a history of pulp necrosis., Methodology: Twenty-three mandibular molars were prepared ex vivo for collection of superficial (surface control), pre-treatment and post-treatment samples 24 h after extraction. Samples were divided into two groups: UIA using 6% NaOCl (n = 11) and GW group (n = 12). All samples were processed using quantitative real-time polymerase chain reaction (qPCR) and 16S rRNA next-generation sequencing to measure microbial diversity before and after the antimicrobial treatment. For qPCR, a t-test (α = .05) was used to compare the log10 reduction. The Chao1 and Shannon indices evaluated alpha diversity. Differences in community composition (beta diversity) were evaluated by analysis of similarity (ANOSIM). Kruskal-Wallis test with Bonferroni corrections was performed to evaluate the differences in abundances genera in the samples., Results: Quantitative real-time polymerase chain reaction revealed an estimated 1.6 and 2.6 log10 reduction for UIA and GW groups respectively (p = .048). An average of 5 ± 4 and 3 ± 5 operational taxonomic units (OTUs) were found in surface's samples in the UIA and GW group respectively. These values were significantly lower (p < .001) compared to the number of preoperative OTUs in those groups (155 ± 79 and 187 ± 121). In assessing beta diversity, there were no significant differences found in pre-treatment samples (R = .090, p = .070 ANOSIM with Bonferroni corrections). Also, no significant differences in community composition were observed in post-treatment samples (R = -.05, p = .829). After treatment, there was a significant reduction of Eubacterium using conventional treatment with UIA and a significant reduction of Prevotella using minimal instrumentation with GW irrigation (p = .007 and p = .002 respectively)., Conclusion: Quantitative PCR analysis revealed a significant reduction in microbial load for GW group. Overall, diversity changes were similar between UIA and GW irrigation in this ex vivo model that used extracted teeth with a history of pulp necrosis. OTUs obtained from the surface sample were negligible and did not affect the statistical outcome of the study., (© 2023 The Authors. International Endodontic Journal published by John Wiley & Sons Ltd on behalf of British Endodontic Society.)

Objectives: This review aims to discuss the implications of anatomy of the root, pulp chamber, and canals on pulpotomy and revitalization procedures (RPs) as treatment alternatives to root canal treatment procedures., Methods: This narrative review was undertaken to address two main questions - why remove vital pulp tissue in teeth with complex canal anatomy when it can be preserved? And why replace the necrotic pulp in teeth with mature roots with a synthetic material when we can revitalize? This review also aims to discuss anatomical challenges with pulpotomy and revitalization procedures., Results: Maintaining the vitality of the pulp via partial or full pulpotomy procedures avoids the multiple potential challenges faced by clinicians during root canal treatment. However, carrying out pulpotomy procedures requires a meticulous understanding of the pulp chamber anatomy, which varies from tooth to tooth. Literature shows an increased interest in the application of RPs in teeth with mature roots; however, to date, the relation between the complexity of the root canal system and outcomes of RPs in necrotic multi-rooted teeth with mature roots is unclear and requires further robust comparative research and long-term follow-up., Conclusions: Whenever indicated, pulpotomy procedures are viable treatment options for vital teeth with mature roots; however, comparative, adequately powered studies with long-term follow-up are needed as a priority in this area. RPs show promising outcomes for necrotic teeth with mature roots that warrant more evidence in different tooth types with long-term follow-ups.  CLINICAL RELEVANCE: Clinicians should be aware of the pulp chamber anatomy, which is subject to morphological changes by age or as a defensive mechanism against microbial irritation, before practicing partial and full pulpotomy procedures. RP is a promising treatment option for teeth with immature roots, but more evidence is needed for its applications in teeth with mature roots. A universal consensus and considerably more robust evidence are needed for the standardization of RPs in teeth with mature roots., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

This study aimed to compare the disinfection effects between a triple antibiotic paste and neodymium-doped yttrium aluminum perovskite (Nd:YAP) laser in pulp regenerative therapy and evaluate corresponding therapeutic effects based on apical radiographs and cone-beam computed tomography (CBCT). Sixty-six immature permanent teeth in 66 patients diagnosed with acute or chronic apical periodontitis were analyzed. All teeth were given pulp regenerative therapy. The patients were categorized into a control (triple antibiotic paste) and an experimental (Nd:YAP laser) group. Teeth in the experimental group were disinfected using an Nd:YAP laser, while those in the control group were disinfected using a triple antibiotic paste. Clinical and radiological examinations were performed every 3-6 months after treatment and followed up for 24 months. Statistical analysis was performed after clinical examination and showed that after one week of treatment, symptoms persisted in two teeth in the control group and two teeth in the experimental group. Two weeks later, the clinical symptoms disappeared in all teeth ( p > 0.05). After 24 months of follow-up, the clinical symptoms recurred in two teeth in the control group and one tooth in the experimental group. On radiographic examination, 31 and 27 teeth showed continued root development, and three and two teeth showed no obvious root development in the control and experimental groups, respectively. The pulp sensibility test was positive in four teeth in both groups, with no significant difference between the two groups ( p > 0.05). The results of this study suggest that endodontic irradiation with an Nd:YAP laser could be an effective alternative to triple antibiotic paste during disinfection of pulp regenerative therapy. Treatment outcomes were assessed using apical radiographs and CBCT, and no negative prognostic effects of the Nd:YAP laser on pulp regenerative therapy were found., Competing Interests: The authors declare no conflict of interest., (©2023 The Author(s). Published by MRE Press.)

Introduction: Persistent infection is always considered the most important reason for the failure of dentin-pulp complex regeneration. The present study aimed to evaluate the effect of the duration of root canal infection (from 1-12 weeks) on the ability of dentin-pulp complex regeneration., Methods: In this animal study, 64 roots of immature premolar teeth of 4 dogs were randomly divided into the following groups: the positive control group, 8 root canals treated with the regenerative endodontic procedure (REP); the negative control group, 12 infected root canals; the intervention groups, 36 root canals infected with supragingival plaque (1, 3, 6, and 12 weeks) and treated with REP; and an additional positive control group, 8 normal roots. After 3 months, the teeth were investigated by radiographic images and immunohistochemical staining (CD31, CD34, and S100 markers). In addition, DSPP gene expression was assessed using a real-time polymerase chain reaction technique., Results: Based on radiologic evaluation among the intervention groups, the highest root canal development (length and width) occurred in the intervention group of 1 week, and the lowest radiologic results were in the intervention groups of 6 and 12 weeks (1-way analysis of variance, P-value < .05). There was a significant difference between the groups in terms of CD31, CD34, S100, and DSPP expression percentage (1-way analysis of variance, P-value < .05); the highest and lowest expression percentages belonged to the 1- and 12-week groups, respectively, among the intervention groups., Conclusions: This study demonstrated that long root canal infection decreased the ability of the body to regenerate the dentin-pulp complex., (Copyright © 2022 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Objectives: This single-blind, randomized clinical trial (RCT) aimed to compare the duration, intensity, and incidence of postoperative pain after foraminal enlargement (FE) with continuous rotary systems and reciprocating instruments., Materials and Methods: Sixty qualified patients were randomly divided into the following two groups: the ProTaper Next group and the WaveOne group. Participants were selected from patients who had both asymptomatic necrosis and asymptomatic apical periodontitis with a single root canal. Endodontic treatment was performed in one visit, and the patients were asked to record their pain severity and analgesic consumption during a 7-day follow-up period using a visual analog scale (VAS). The data were analyzed using the Mann-Whitney U-test and Chi-square test (P < 0.05)., Results: A significant difference was observed between the two groups during the first two days of follow-up (P < 0.05). Pain experience was higher in FEs that had been created by reciprocating instruments than by continuous rotary systems. There were no significant differences in VAS pain scores over the other days (P > 0.05). None of the patients had severe postoperative pain during the follow-up period. No significant differences were observed in the prevalence of analgesic consumption between either group (P > 0.05)., Conclusions: This RCT indicates that in the 2-day follow-up period after endodontic treatment, FEs created by reciprocated instruments associated more postoperative pain than continuous rotary systems., Competing Interests: None

Aim: To detect the unknown components of the oral microbiome and the effects of root canal treatment in a Turkish population and to evaluate the changes in microbial diversity in the root canals before and after treatment., Methodology: Single-rooted central and lateral maxillary incisors with one canal were chosen from 20 patients. Baseline samples of intact intracanal microbiota were collected from 20 root canals of permanent teeth with necrotic pulps using sterile paper points. After root canal preparation, the root canals were filled with a calcium hydroxide paste for 7 days. Calcium hydroxide was removed from root canal with 2.5% sodium hypochlorite and 17% EDTA using passive ultrasonic irrigation (PUI). A second bacteriologic samples were taken with sterile paper points prior to root filling. The samples were processes with DNase-I treatment using next-generation sequencing (NGS). Reduction in bacterial numbers during root canal treatment was evaluated using real-time quantitative PCR (qPCR). All statistical analyses were conducted using the MINITAB 17 software (Minitab Ltd. Co., Coventry, UK). A one-sample t-test was used to analyse the data. Statistical significance was accepted at P < 0.05., Results: Relative abundances of Mycoplasma sp., Paludibacter sp., Tannerella sp., Prevotella spp. and an uncultured species from the order Bacteroidales decreased with root canal preparation and medication (98.7%, 99.8%, 98.8%, 97.7% and 99.3%, respectively), whilst the relative abundances of Methylobacterium sp., Corynebacterium sp. and Streptococcus infantis increased (93.1%, 94.8% and 99.4%, respectively). Considerable numbers of Streptophyta species were detected before and after treatment. The ratio of Agrobacterium sp. in the treated teeth community and the ratio of order Streptophyta in the infected canals had negative correlations with the success of bacterial elimination., Conclusions: The combination of NGS and qPCR techniques resulted in detection of previously unknown components of the oral microbiome and the effects of root canal treatment on their relative abundance in a Turkish population., (© 2018 International Endodontic Journal. Published by John Wiley & Sons Ltd.)

Competing Interests: Competing interests: None declared.

Aims: To determine the efficacy of a single session protocol (SSP) in the reduction of septic content of primary teeth root canals and identify the persistence of bacterial species associated with unsuccessful treatment., Methods: Primary teeth root canals (16) with pulp necrosis and peri-radicular lesions were treated. Samples were collected at baseline (T1), and after chemo-mechanical preparation, before filling (T2). Identification of the microorganisms was determined using checkerboard DNA-DNA hybridisation., Statistical Analysis: Wilcoxon test was applied for comparison of mean number of species, proportion and mean count of each species between the evaluation times., Results: Significant reductions were found in the mean number of bacteria species between T1 and T2 (p < 0.05), but not for the reduction in proportion (p > 0.05). There was a reduction (6.0-4.6) of the mean number of species associated with failure, without statistical significance., Conclusion: The SSP was capable of significantly reducing the septic content, even though, many of the bacteria associated with failure persisted at the time of root canal filling.

Objective: This clinical study compared the effectiveness of 7- and 14-day intracanal medications in the reduction of bacteria/endotoxins from primarily infected root canals and determined their antigenicity against macrophages through the levels of cytokines., Methods: Seventy-two primarily infected teeth were randomly divided into six groups according to medication and time of application: 7-day groups = G1, Ca(OH) 2 + saline solution (SSL); G2, Ca(OH) 2 + 2% chlorhexidine (CHX) gel; and G3, 2% CHX gel and 14-day groups = G4, Ca(OH) 2 + SSL; G5, Ca(OH) 2 + 2% CHX gel; and G6, 2% CHX gel (all groups, n = 12). Bacterial and endotoxin samples were collected from root canals and inflammatory cytokines of macrophages supernatants. Culture techniques were used to determine bacterial counts and limulus amebocyte lysate (LAL) assay to quantify endotoxins. IL-1β, TNF-α, and PGE 2 were measured by ELISA-assay., Results: With regard to the bacterial reduction, no differences were found between all protocols tested (p > 0.05). The CHX protocols (G3 and G6) exhibited the lowest effectiveness against endotoxins (p < 0.05). All protocols were effective in lowering the levels of IL-1β, TNF-α, and PGE 2 (p < 0.05), with no difference between the medications tested on days 7 or 14 (p > 0.05). Particularly, the 7-day CHX-protocol (G3) exhibited the lowest effectiveness in lowering the levels of most cytokines compared to the 14-day protocols (G6) (p < 0.05)., Conclusions: All the 7- and 14-day intracanal medications were effective in reducing bacteria and endotoxins as well as in lowering the levels of inflammatory cytokines, with CHX showing limited effectiveness against endotoxins. Moreover, 7-day CHX-protocol exhibited the lowest effectiveness in lowering the levels of most cytokines compared to the 14-day protocols., Clinical Significance: Seven-day CHX protocol is the less effective protocol and should be carefully applied by the clinician.

The aim of this scoping study was to evaluate the survival rate and nature of tissue formed inside root canals of human immature permanent teeth with necrotic pulps (NIPT) under root canal revascularization (RCR). The search was performed in SciVerse Scopus®, PubMed/MEDLINE, Web of Science®, BIREME and in the grey literature up to November 2015. The keywords were selected using MeSH terms and DECs. Two independent reviewers scrutinized the records obtained considering specific inclusion criteria. The included studies were evaluated in accordance with a modified Arksey and O' Malley's framework. From 375 studies that were evaluated, 75 were included. A total of 367 NIPT were submitted to RCR, from which only 21 needed further endodontic treatment. The weighted mean follow-up time was 17.6 months. The data were derived mainly from case reports (69%) or small case series (15%). NaOCl [0.5-6%] was applied as the disinfecting solution in almost all studies. Triple antibiotic paste was as effective as Ca(OH) 2 as on intracanal medicament. De novo tissue was cementum and poorly mineralized bone positive to bone sialoprotein (BSP) but negative to dentine sialoprotein (DSP). Failures were associated mainly with reinfection of the root canal. The majority of included studies reported a significant increase in both root length and width. However, as most of these data came from case reports, they must be interpreted with care, as most were focused on treatment successes (not failures). Therefore, well-designed randomized controlled trials comparing RCR with available apexification treatments are needed to address this gap in the literature., (© 2016 International Endodontic Journal. Published by John Wiley & Sons Ltd.)

Introduction: The purpose of this case series was to report the clinical and radiographic results of a pulp regenerative procedure using platelet-rich fibrin (PRF), a second-generation platelet concentrate, in immature teeth with necrotic pulps., Methods: Root canal revascularization using PRF was performed on 4 immature teeth with necrotic pulps. After access cavity preparation, the root canals were irrigated with low concentration sodium hypochlorite solution (1.5% sodium hypochlorite [20 mL/canal, 5 minutes]) and then irrigated with saline (20 mL/canal, 5 minutes). Equal proportions (167 mg) of ciprofloxacin, metronidazole, and cefaclor were mixed and diluted to a final concentration of 1 g/mL. Finally, the canal was sealed with 3-4 mm of a temporary restorative material, and patients were dismissed for 2 to 3 weeks. At the second appointment, 9 mL of the patient's whole blood was obtained and centrifuged to prepare a PRF clot. Canals were irrigated with 17% EDTA, and a sharp spreader was inserted beyond the apex. Then, the PRF clot was placed inside the root canals, and Biodentine (Septodont, Saint-Maur, France) was placed directly over the PRF. The teeth were restored permanently with glass ionomer cement and composite resin., Results: Clinical examinations revealed that all cases were asymptomatic at the recall appointments at 1, 3, 6, 12, and 18 months. Radiographs revealed resolution of the periapical lesions, further root development, and apical closure in all cases., Conclusions: On the basis of the short-term results up to 12 months, PRF clots acted as successful scaffolds for the regeneration of pulpal contents in immature teeth with necrotic pulps., (Copyright © 2016 American Association of Endodontists. All rights reserved.)

Aim: To report cases with morphologic variations in mandibular premolars., Background: Mandibular premolars have earned the reputation for having aberrant anatomy. The occurrence of three canals with three separate (type V, Vertucci) foramina in mandibular premolars is very rare. In this report, three cases are presented involving the root canal treatment of mandibular premolars with three different root and canal configurations. The present report also emphasizes the use of the dental operating microscope to enhance visualization., Case Description: Correlation between radiographic findings, use of dental operating microscope and knowledge of aberrant anatomy helps to identify, locate and treat the aberrant anatomy of the tooth., Clinical Significance: The treatment was successful as all canals were identified and filled and also as evidenced by relief of symptoms., Conclusion: Success is largely dependent on the use of magnification, which aided in identifying the location of the three individual root canal orifices; thus emphasizing the need to familiarize ourselves with dental microscopy, to obtain maximal anatomic information in endodontic practice.

Introduction: Revascularization outcome depends on microbial elimination because apical repair will not happen in the presence of infected tissues. This study evaluated the microbial composition of traumatized immature teeth and assessed their reduction during different stages of the revascularization procedures performed with 2 intracanal medicaments., Methods: Fifteen patients (7-17 years old) with immature teeth were submitted to the revascularization procedures; they were divided into 2 groups according to the intracanal medicament used: TAP group (n = 7), medicated with a triple antibiotic paste, and CHP group (n = 8), dressed with calcium hydroxide + 2% chlorhexidine gel. Samples were taken before any treatment (S1), after irrigation with 6% NaOCl (S2), after irrigation with 2% chlorhexidine (S3), after intracanal dressing (S4), and after 17% EDTA irrigation (S5). Cultivable bacteria recovered from the 5 stages were counted and identified by means of polymerase chain reaction assay (16S rRNA)., Results: Both groups had colony-forming unit counts significantly reduced after S2 (P < .05); however, no significant difference was found between the irrigants (S2 and S3, P = .99). No difference in bacteria counts was found between the intracanal medicaments used (P = .95). The most prevalent bacteria detected were Actinomyces naeslundii (66.67%), followed by Porphyromonas endodontalis, Parvimonas micra, and Fusobacterium nucleatum, which were detected in 33.34% of the root canals. An average of 2.13 species per canal was found, and no statistical correlation was observed between bacterial species and clinical/radiographic features., Conclusions: The microbial profile of infected immature teeth is similar to that of primarily infected permanent teeth. The greatest bacterial reduction was promoted by the irrigation solutions. The revascularization protocols that used the tested intracanal medicaments were efficient in reducing viable bacteria in necrotic immature teeth., (Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Introduction: Recent reviews lament the lack of evidence on the efficacy of regenerative procedures to induce further root maturation despite claims of a paradigm shift in the way infected, necrotic immature teeth with arrested root development can be endodontically treated. The majority of reports are either case series or successful case reports where nonstandardized images may make interpretation uncertain., Methods: This prospective clinical study reports on preliminary outcomes of regenerative endodontic procedures carried out on 16 teeth, 3 mandibular premolars and 13 traumatized central incisors, after 18-month reviews. Qualitative analysis of resolution of periapical radiolucencies and apical closure was undertaken. Quantitative analysis compared preoperative and recall radiographs by using a geometrical imaging program that calculated percentage changes in root length and dentin wall thickness., Results: Qualitative assessment showed 90.3% resolution of the periapical radiolucency. Apical closure was assessed as incomplete in 47.2% and complete apical closure in 19.4% of cases. Quantitative assessment showed change in root length varying from -2.7% to 25.3% and change for root dentin thickness of -1.9% to 72.6%., Conclusions: Patterns of continued root maturogenesis were variable at 18-month review. Reviews at 36 months showed continued root maturogenesis for 2 cases. Quantitative analysis can control for changes in angulation but may introduce other measurement errors. However, not all anterior teeth were suitable for TurboReg assessment because overlapping of the cementoenamel junctions and/or further eruption of teeth often precluded stable landmark positioning. Discoloration of the crown was a common consequence, with unaesthetic results in 10 of the 16 cases., (Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

A complication of endodontic treatment is over-preparation of the tooth structure in an attempt to access calcified pulp chambers and root canals. This could result in thin root walls that might compromise the long-term prognosis of the tooth. There are various treatment options when such a complication occurs, among them, extraction of the compromised tooth and its replacement with a dental implant. This clinical report describes a nonsurgical, multidisciplinary treatment alternative where a maxillary anterior tooth with a thinned root wall was successfully saved by repairing the damaged root to its original thickness using a composite resin material and subsequently restoring with a cast post and core and a crown.

Introduction: The C-shaped configuration is rare in the upper first molar.The purpose of this article is to present 2 cases diagnosed during endodontic therapy and perform a literature review of this anatomy in the upper first molar., Methods: Endodontic therapy was performed by using a dental operating microscope and a cone-beam computed tomography analysis for better understanding of this anatomy. A literature search was conducted to identify and compare all the published cases of C-shaped upper first molar., Results: Before the cases reported in this article, only 5 cases were available in the published literature. Three different types of C-shaped configurations in the upper first molar have been presented., Conclusions: The C-shaped maxillary first molar is a rare anatomic configuration. The use of the dental operating microscope may help in the endodontic therapy of these cases. Three types of C-shaped configurations have been reported; the fusion of the distobuccal root with the palatal root appears to be the most usual one., (Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Introduction: The aim of this study was to investigate the capacity of endodontic regenerative procedures combining an induced blood clot, platelet-rich plasma (PRP), and bone marrow aspirate (BMA) to regenerate dental pulp in canine closed-apex necrotic teeth., Methods: Apical periodontitis was induced in 20 upper and lower premolars of 2 dogs. After biomechanical preparation, enlargement to a #60 file, and disinfection with a triantibiotic paste for 28 days, the roots were randomly assigned to 4 treatment groups: blood clot (BC), BC + PRP gel, BC + BMA gel, and BC + BMA/PRP gel. Negative controls were also included. After a 3-month follow-up period, the animals were killed., Results: Histologic analysis showed the presence of newly formed vital tissues (connective, cement-like, and bone-like tissue) in 23 of the 32 treated roots (71.87%). There was no statistically significant difference between the treatment groups., Conclusions: New vital tissues were formed and characterized as connective, cementum-like, or bone-like, but not as pulp-like tissue; PRP and/or BMA did not improve the tissue ingrowth., (Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Endodontic management of teeth with aberrant root canal morphology can be challenging. This article presents a case in which multiple angulated radiographs and a dental operating microscope clearly revealed the presence of 3 root canals in a right mandibular central incisor with 2 different canal patterns. This case report emphasizes the importance of utilizing a dental operating microscope to understand unusual root canal morphology.

Aim: To compare the antibacterial efficacy of two instrumentation techniques, one using hand nickel-titanium (NiTi) instruments and the other using rotary NiTi instruments, in root canals of teeth with apical periodontitis., Methodology: Root canals from single-rooted teeth were instrumented using either hand NiTi instruments in the alternated rotation motion technique or rotary BioRaCe instruments. The irrigant used in both groups was 2.5% NaOCl. DNA extracts from samples taken before and after instrumentation were subjected to quantitative analysis by real-time polymerase chain reaction (qPCR). Qualitative analysis was also performed using presence/absence data from culture and qPCR assays., Results: Bacteria were detected in all S1 samples by both methods. In culture analysis, 45% and 35% of the canals were still positive for bacterial presence after hand and rotary NiTi instrumentation, respectively (P > 0.05). Rotary NiTi instrumentation resulted in significantly fewer qPCR-positive cases (60%) than hand NiTi instrumentation (95%) (P = 0.01). Intergroup comparison of quantitative data showed no significant difference between the two techniques., Conclusion: There was no significant difference in bacterial reduction in infected canals after instrumentation using hand or rotary NiTi instruments. In terms of incidence of positive results for bacteria, culture also showed no significant differences between the groups, but the rotary NiTi instrumentation resulted in more negative results in the more sensitive qPCR analysis., (© 2013 International Endodontic Journal. Published by John Wiley & Sons Ltd.)

Aberrant root canal anatomy is diagnostically and clinically challenging for clinicians. The most common root canal configuration of human molars is 2 roots and 3 canals, but various combinations may still exist. Third molars are known to have the most unusual anatomy among human teeth. Restorative, prosthetic, and orthodontic considerations often require endodontic treatment of third molars in order for them to be retained as functional components of the dental arch. The present case report demonstrates unusual root canal morphology of the mandibular third molar. Roentgenographic examination, which included spiral CT scan, revealed 3 separate mesial roots in tooth #48 with 3 independent canals and 3 canal orifices, indicating an endodontic rarity. The present case report puts impetus on exploration of additional canals using advanced diagnostic aids, such as spiral computed tomography, which can have a huge impact on the successful outcome of endodontic therapy., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Introduction: The aim of this randomized, controlled, prospective clinical study was to determine if foraminal enlargement instrumentation during endodontic treatment is associated with more postoperative pain compared with standard nonenlargement instrumentation., Methods: Forty volunteers with a single root canal were diagnosed with asymptomatic necrosis with apical periodontitis and randomized into 2 experimental groups (ie, the control group and the foraminal enlargement group). Endodontic treatment was performed in a single visit, and volunteers were instructed to record pain intensity (ie, none, slight, moderate, and severe). Scores from 1 to 4 were attributed to each kind of pain after 12, 24, and 48 hours. The Kolmogorov-Smirnov and Student's t tests were used to determine significant differences at P < .05., Results: No statistically significant age difference was found between the groups (P > .05, Student's t test). Postoperative pain showed no statistically significant difference between the groups at any observation period (P > .05). Also, no significant difference was observed in the mean number of analgesic tablets used between the groups (P > .05)., Conclusions: The foraminal enlargement and nonenlargement techniques resulted in the same postoperative pain and necessity for analgesic medication. This may suggest that the use of foraminal enlargement should be performed for endodontic treatment previsibility without increasing postoperative pain., (Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Introduction: This in vivo study used molecular microbiology methods to evaluate the effects of passive ultrasonic irrigation (PUI) as a supplementary disinfecting step after root canal preparation., Methods: Samples were taken from 10 necrotic root canals of teeth with apical periodontitis before (S1) and after rotary nickel-titanium instrumentation using 2.5% NaOCl as the irrigant (S2) and then after PUI for NaOCl activation (S3). The parameters examined included the incidence of positive broad-range polymerase chain reaction (PCR) results for bacterial presence, the impact on bacterial diversity evaluated by PCR-denaturing gradient gel electrophoresis (DGGE), the quantitative bacterial reduction determined by real-time PCR, and the identification of persistent species by clone library analysis., Results: All S1 samples were positive for bacteria in all tests. Treatment procedures were significantly effective in reducing the incidence of positive results for bacteria, the number of bacterial cells (infectious bioburden), and the bacterial diversity (number of species and abundance). However, the supplementary PUI approach did not succeed in significantly enhancing disinfection beyond that achieved by chemomechanical preparation. Several bacterial species/phylotypes were identified in post-treatment samples that were positive for bacteria., Conclusions: Findings from this clinical study including a small sample size suggest that PUI can be ineffective in significantly improving disinfection of the main root canal after chemomechanical procedures., (Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

This case report describes the nonsurgical endodontic management of a maxillary first molar with the unusual morphology of three separate buccal roots. An accurate assessment of this morphology was made with the help of cone-beam computed tomography (CBCT). This report also describes the varied root morphology associated with maxillary first molars and the role of CBCT as a diagnostic tool for managing these complex cases successfully.

Introduction: Recent in vitro studies that use an apical negative pressure irrigation system, EndoVac, have demonstrated promising results in the production of debris-free root canals, while also preventing potential extrusion of irrigants into the periapical region. We conducted a randomized, controlled, prospective clinical study to determine whether the use of EndoVac irrigation (EndoVac group) was more efficient compared with standard needle irrigation (control group) in obtaining canals from which microbes could not be cultivated., Methods: Routine endodontic therapy was performed in 48 patients with necrotic, single-rooted, single-canal teeth. The patients were randomly assigned to either the EndoVac group (n = 25) or control group (n = 23). Irrigation with either method was carried out with 0.5% sodium hypochlorite. After surface disinfection, before instrumentation and on completion of chemomechanical preparation, intracanal microbial samples were obtained and cultured under anaerobic conditions. The frequency of microbial cultivability by using either irrigation system was analyzed., Results: The frequency of obtaining culture-negative root canals was 90.9% and 82.6% for the control group and EndoVac group, respectively. There was no significant difference in the antimicrobial efficacy of either control group or EndoVac group (Fisher exact test, P = .665). Furthermore, no significant association between study variables and the irrigation systems' antimicrobial efficacy was found (P > .05)., Conclusions: The results of this prospective in vivo study demonstrate that the antimicrobial efficacy of EndoVac irrigation is comparable to that of standard irrigation., (Copyright © 2012 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Introduction: This study analyzed the in vivo microbiological status of the root canal systems of mesial roots of mandibular molars with primary apical periodontitis after 1- or 2-visit endodontic treatment., Methods: Mesial root canals were instrumented by using either a combination of K3 and LightSpeed instruments (mesiobuccal canals) or the ProTaper system (mesiolingual canals), with 5% NaOCl irrigation. Patency files were used. Smear layer was removed, and a final rinse with 5 mL of 2% chlorhexidine was performed. In the 2-visit group (7 roots, 14 canals), canals were medicated with calcium hydroxide for 1 week and then obturated by using the continuous wave of compaction technique. In the 1-visit group (6 roots, 12 canals), canals were immediately obturated after chemomechanical procedures. Teeth were extracted 1 week after root canal instrumentation and processed for histobacteriologic analysis., Results: In the 1-visit group, no case was completely free of bacteria; residual bacteria occurred in the main root canal (5 of 6 cases), isthmus (5 of 6), apical ramifications (4 of 6), and dentinal tubules (5 of 6). In the 2-visit group, 2 cases were rendered bacteria-free; residual bacteria were found in the main canal only in 2 cases (none of them with persistent dentinal tubule infection), in the isthmus (4 of 7 cases), and in ramifications (2 of 7). The 2 instrumentation techniques performed similarly. When filling material was observed in ramifications, it was usually intermixed with necrotic tissue, debris, and bacteria., Conclusions: The 2-visit protocol by using an interappointment medication with calcium hydroxide resulted in improved microbiological status of the root canal system when compared with the 1-visit protocol. Residual bacteria were more frequent and abundant in ramifications, isthmuses, and dentinal tubules when root canals were treated without an interappointment medication. Apical ramifications and isthmuses were never completely filled. The use of an antibacterial interappointment agent is necessary to maximize bacterial reduction before filling., (Copyright © 2012 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Introduction: Endotoxins are one of the etiologic agents involved in the pathogenesis of apical periodontitis. The objectives of this clinical study were to investigate the effects of endodontic treatment by using different irrigants on endotoxins in root canals with pulp necrosis and apical periodontitis and to evaluate the cytotoxic effects., Methods: Thirty-six root canals were selected. Samples were collected before (S1) and after instrumentation (S2). The root canals were divided into 3 groups (n = 12) according to the irrigant combination used: CLX + LW, 2% chlorhexidine gel + calcium hydroxide (0.14%, limewater); CLX + PmB, chlorhexidine + polymyxin B; CLX (control), chlorhexidine + saline. The third sampling (S3) was performed after ethylenediaminetetraacetic acid and S4 after intracanal medication (CLX + calcium hydroxide for 14 days). Endotoxins were quantified by the chromogenic Limulus amebocyte lysate assay, and cytotoxic effects were evaluated by the production of cytokines (interleukin-1ß, tumor necrosis factor α) in macrophages (RAW 264.7) stimulated with the root canal content., Results: Endotoxins were detected in all root canals before instrumentation (S1). Group CLX + LW presented the greatest endotoxin reduction after instrumentation (99.18%), which was similar to group CLX + PmB (96.42%, P > .05) and different from group CLX (90.78%, P < .05). The intracanal medication promoted important endotoxin neutralization, with a reduction of 99.2% to 100%. The root canal content induced a higher production of tumor necrosis factor α and interleukin-1β in S1 samples compared with samples obtained after treatment., Conclusions: The combination of CLX and limewater as irrigant was the most effective in reducing endotoxins in root canals, and intracanal medication was important to neutralize the cytotoxic effects., (Copyright © 2012 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Dental practitioners are often called upon to provide endodontic services for patients in pain. Maxillary lateral incisors may present added concerns when planning endodontic services. Dens invaginatus (DI) Oehlers Type 3 classification is a relatively rare phenomenon that occurs primarily in maxillary lateral incisors. It is important to consider this condition in all maxillary lateral incisors and to be aware that it can be difficult to treat when the invagination extends past the epithelial attachment apparatus. Successful outcome may be severely compromised in these cases and requires interdisciplinary approaches. This case study describes a maxillary lateral incisor with DI Type 3 that was refractory to treatment.

Aim: To describe the successful non-surgical endodontic management of a permanent maxillary lateral incisor tooth with four root canals., Summary: Aberrant morphology of root canals can occur in any tooth, including maxillary lateral incisors. In the presented case, clinical examination and radiographs clearly depicted the presence of four root canals in a right maxillary lateral incisor. The differential diagnosis included fusion, gemination, dens invaginatus or a combination of these. The report emphasises the need for attention during root canal treatment of maxillary lateral incisors., Key Learning Points: • Clinicians should be aware of the variable root canal anatomy in maxillary lateral incisor teeth. • Careful examination of radiographs and the internal anatomy of teeth are essential prerequisites for successful root canal treatment. • Four root canals in maxillary lateral incisors is a possibility., (© 2011 International Endodontic Journal.)

Introduction: The aim of this study was to evaluate the enamel matrix derivative (EMD) biomaterial in nonvital immature teeth., Methods: To arrest root development, pulpectomies were performed in the lower first molars of 36 4-week-old rats; the cavities were left exposed to the oral environment for 3 weeks. Then, chemical disinfection was performed, and triple antibiotic paste (TAP) or EMD was applied in the root canals. A control group did not receive any treatment. Radiographic and histological data were evaluated after 3 and 6 weeks., Results: At 3 weeks, TAP promoted a milder inflammatory response and increased root lengths compared with the control group. At 6 weeks, root development and reduced periapical lesions could be observed in both test groups, mainly because of the deposition of a cementum-like tissue. EMD promoted narrower canals compared with TAP (P < .05)., Conclusions: EMD deserves attention as a potential tool in the treatment of nonvital immature teeth. The ingrowth of cementum-like tissues into canal spaces favored dental wall thickness and may contribute to tooth resistance and support., (Copyright © 2012 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Aim: To investigate the root canal microbiota of primary teeth with apical periodontitis and the in vivo antimicrobial effects of a calcium hydroxide/chlorhexidine paste used as root canal dressing., Design: Baseline samples were collected from 30 root canals of primary teeth with apical periodontitis. Then, the root canals were filled with a calcium hydroxide paste containing 1% chlorhexidine for 14 days and the second bacteriologic samples were taken prior to root canal filling. Samples were submitted to microbiologic culture procedure to detect root canal bacteria and processed for checkerboard DNA-DNA hybridization., Results: Baseline microbial culture revealed high prevalence and cfu number of anaerobic, black-pigmented bacteroides, Streptococcus, and aerobic microorganisms. Following root canal dressing, the overall number of cfu was dramatically diminished compared to initial contamination (P <0.05), although prevalence did not change (P > 0.05). Of 35 probes used for checkerboard DNA-DNA hybridization, 31 (88.57%) were present at baseline, and following root canal dressing, the number of positive probes reduced to 13 (37.14%). Similarly, the number of bacterial cells diminished folowing application of calcium hydroxide/chlorhexidine root canal dressing (P = 0.006)., Conclusion: Apical periodontitis is caused by a polymicrobial infection, and a calcium hydroxide/chlorhexidine paste is effective in reducing the number of bacteria inside root canals when applied as a root canal dressing., (2011 The Authors. International Journal of Paediatric Dentistry © 2011 BSPD, IAPD and Blackwell Publishing Ltd.)

Introduction: Many anatomical variations can occur within the mandibular first molar. Commonly, 3-4 canals are located, but as many as 6-7 canals have been reported., Methods: This report describes a case of a mandibular first molar with 6 separate canals (3 mesial and 3 distal) that was instrumented with conventional hand and rotary files and obturated by using a hybrid warm vertical compaction technique., Results: Recall examination as far as 3 years post-treatment found no sensitivity to percussion or palpation and recall radiographs after treatment show resolution of the previous apical periodontitis., Conclusions: The existence of such teeth as these underlies the importance of looking for additional canals., (Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Introduction: This culture-independent molecular microbiology study evaluated the antimicrobial effects of chemomechanical preparation supplemented by intracanal medication during treatment of teeth with apical periodontitis., Methods: Samples were taken from 24 necrotic root canals at the baseline (S1), after chemomechanical preparation by using 2.5% NaOCl as the irrigant (S2), and after a 7-day interappointment medication with calcium hydroxide paste in either glycerin (CHG) or camphorated paramonochlorophenol/glycerin (CHPG) (S3). Bacterial, archaeal, and fungal presence was evaluated by polymerase chain reaction (PCR), and bacterial identifications were performed by a closed-ended reverse-capture checkerboard approach targeting 28 candidate endodontic pathogens., Results: All S1 samples were positive for bacteria but negative for both archaea and fungi. Treatment procedures were highly effective in reducing the bacterial levels and number of taxa. Overall, 46% of S2 samples and 62.5% of S3 samples were PCR-negative for bacteria. Specifically, S2 and S3 samples yielded negative PCR results in 50% and 58% of the canals in the CHG group and in 42% and 67% of the canals in the CHPG group, respectively. Except for comparisons with S1 samples, no other statistically significant differences were observed for intragroup and intergroup comparisons involving S2 and S3. Several taxa were still found in S2 and S3 samples, and the most prevalent were Propionibacterium acnes and Streptococcus species., Conclusions: Bacterial levels and number of taxa were substantially reduced after chemomechanical preparation and intracanal medication. However, presence of detectable levels of persisting bacteria in many cases indicates that the search for more effective antimicrobial treatment strategies should be stimulated., (Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Introduction: The objective of this study was to evaluate the antimicrobial effects of photodynamic therapy (PDT) on infected human teeth ex vivo., Methods: Fifty-two freshly extracted teeth with pulpal necrosis and associated periradicular radiolucencies were obtained from 34 subjects. Twenty-six teeth with 49 canals received chemomechanical debridement (CMD) with 6% NaOCl, and 26 teeth with 52 canals received CMD plus PDT. For PDT, root canal systems were incubated with methylene blue (MB) at concentration of 50 μg/mL for 5 minutes, followed by exposure to red light at 665 nm with an energy fluence of 30 J/cm(2). The contents of root canals were sampled by flushing the canals at baseline and after CMD alone or CMD+PDT and were serially diluted and cultured on blood agar. Survival fractions were calculated by counting colony-forming units (CFUs). Partial characterization of root canal species at baseline and after CMD alone or CMD+PDT was performed by using DNA probes to a panel of 39 endodontic species in the checkerboard assay., Results: The Mantel-Haenszel χ(2) test for treatment effects demonstrated the better performance of CMD+PDT over CMD (P = .026). CMD+PDT significantly reduced the frequency of positive canals relative to CMD alone (P = .0003). After CMD+PDT, 45 of 52 canals (86.5%) had no CFUs as compared with 24 of 49 canals (49%) treated with CMD (canal flush samples). The CFU reductions were similar when teeth or canals were treated as independent entities. Post-treatment detection levels for all species were markedly lower for canals treated by CMD+PDT than they were for those treated by CMD alone. Bacterial species within dentinal tubules were detected in 17 of 22 (77.3%) and 15 of 29 (51.7%) canals in the CMD and CMD+PDT groups, respectively (P = .034)., Conclusions: Data indicate that PDT significantly reduces residual bacteria within the root canal system, and that PDT, if further enhanced by technical improvements, holds substantial promise as an adjunct to CMD., (Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Introduction: Immature teeth with open apices treated with conventional nonsurgical root canal treatment often have a poor prognosis as a result of the increased risk of fracture and susceptibility to recontamination. Regenerative endodontics represents a new treatment modality that focuses on reestablishment of pulp vitality and continued root development. This clinical procedure relies on the intracanal delivery of a blood clot (scaffold), growth factors (possibly from platelets and dentin), and stem cells. However, to date, the clinical presence of stem cells in the canal space after this procedure has not been demonstrated. The purpose of this clinical study was to evaluate whether regenerative endodontic procedures are able to deliver stem cells into the canal space of immature teeth in young patients and to identify the possible tissue origin for these cells., Methods: After informed consent, the first appointment consisted of NaOCl irrigation and treatment with a triple antibiotic paste. One month later, the root canal space was irrigated with sterile saline, and bleeding was evoked with collection of samples on paper points. Real-time reverse-transcription polymerase chain reaction and immunocytochemistry were conducted to compare the gene transcripts and proteins found in the root canal sample with levels found in the systemic circulation., Results: Molecular analyses of blood collected from the canal system indicated the significant accumulation of transcripts for the stem cell markers CD73 and CD105 (up to 600-fold), compared with levels found in the systemic blood. Furthermore, this effect was selective because there was no change in expression of the differentiation markers ALK-P, DSPP, ZBTB16, and CD14. Histologic analyses demonstrated that the delivered cells expressed both CD105 and STRO-1, markers for a subpopulation of mesenchymal stem cells., Conclusions: Collectively, these findings demonstrate that the evoked-bleeding step in regenerative procedures triggers the significant accumulation of undifferentiated stem cells into the canal space where these cells might contribute to the regeneration of pulpal tissues seen after antibiotic paste therapy of the immature tooth with pulpal necrosis., (Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Introduction: This clinical study was conducted to investigate the ability of chemomechanical preparation with 2.5% NaOCl + 17% ethylenediaminetetraacetic acid (EDTA) and rotary nickel-titanium (NiTi) system in removing endotoxin from primary root canal infection with apical periodontitis., Methods: Twenty-one root canals with necrotic pulps were selected. Samples were collected before (s1) and after chemomechanical preparation (s2). The limulus amebocyte lysate (LAL) assay was used to quantify endotoxins., Results: The LAL assay indicated that endotoxins were present in 100% of the root canals investigated (19/19) before (s1) and after chemomechanical preparation (s2). Analyses of the quantitative data revealed that the endotoxin content was significantly reduced at s2 (98.06%) compared with that at s1 (P < .05)., Conclusions: Our findings indicate that chemomechanical preparation with 2.5% NaOCl + 17% EDTA and rotary NiTi files was effective in reducing endotoxin load in the root canal infection from primarily infected teeth with apical periodontitis., (Copyright © 2010 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Introduction: This study reports the antimicrobial effect of photodynamic therapy (PDT) combined with endodontic treatment in patients with necrotic pulp infected with microflora resistant to a previous antibiotic therapy., Methods: Thirty anterior teeth from 21 patients with periapical lesions that had been treated with conventional endodontic treatment and antibiotic therapy were selected. Microbiological samples were taken (1) after accessing the root canal, (2) after endodontic therapy, and (3) after PDT., Results: All the patients had at least 1 microorganism resistant to antibiotics. PDT used polyethylenimine chlorin(e6) as a photosensitizer and a diode laser as a light source (P = 40 mW, t = 4 minutes, E = 9.6 J). Endodontic therapy alone produced a significant reduction in numbers of microbial species but only 3 teeth were free of bacteria, whereas the combination of endodontic therapy with PDT eliminated all drug-resistant species and all teeth were bacteria-free., Conclusions: The use of PDT added to conventional endodontic treatment leads to a further major reduction of microbial load. PDT is an efficient treatment to kill multi-drug resistant microorganisms., (Copyright 2010 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

This clinical article describes 4 different case reports of maxillary first molars with unusual anatomy of 6 root canals and their endodontic management. Treating these additional canals in maxillary first molars might be challenging. Inability to locate and properly treat these extra canals might lead to failures. A thorough knowledge of root canal morphology and the proper use of microscopes increase chances for successful clinical results. Because presence of these extra canals is not unusual and naming these canals still remains elusive, a new nomenclature is suggested for ease of communication., (Copyright 2010 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Aim: The purpose of this case report is to describe a nonsurgical endodontic treatment of a mandibular left second premolar with two separate roots and three distinct root canals., Background: In endodontics, the possible existence of extra canals must be considered before endodontic treatment is instituted. A wide morphological variation of the root canal system is known to exist., Case Description: A 36-year-old male patient was referred for endodontic treatment on the left mandibular second premolar. Radiographic examination of the involved tooth revealed an unusual, complex root canal anatomy. There was an irregular root morphology consisting of two distinct roots and three canals., Summary: This case report describes the successful nonsurgical endodontic treatment of a mandibular left second premolar with two separate roots and three distinct root canals filled using size 35 Thermafil gutta-percha carriers and AH Plus sealer. On the one-year follow-up radiograph, the tooth was asymptomatic, confirming adequate healing with no complications., Clinical Significance: Even in a tooth with an extremely complex root canal morphology, conventional endodontic treatment without surgical intervention can result in adequate healing without any complications.

Objective: The aim of this study was to compare in vivo the efficacy of 2 root canal disinfection techniques (apical negative pressure irrigation versus apical positive pressure irrigation plus triantibiotic intracanal dressing) in immature dog teeth with apical periodontitis., Study Design: Two groups of root canals with pulp necrosis and apical periodontitis were evaluated according to the disinfection technique: group 1: apical negative pressure irrigation (EndoVac system); and group 2: apical positive pressure irrigation (conventional irrigation) plus triantibiotic intracanal dressing. The first sample (S1) was collected after lesions were radiographically visible, and the second sample (S2) was collected after apical negative pressure irrigation (group 1) or conventional irrigation/triantibiotic dressing (group 2). All samples were seeded in a culture medium for anaerobic bacteria. Colony-forming unit counts were analyzed statistically by the Mann-Whitney test (alpha = .05)., Results: Microorganisms were present in 100% of canals of both groups in S1. In S2, microorganisms were absent in 88.6% of group 1's canals and 78.28% of group 2's canals. There was no significant difference between the groups in either S1 (P = .0963) or S2 (P = .0566). There was significant (P < .05) bacterial reduction from S1 to S2 in both groups., Conclusion: In immature teeth with apical periodontitis, use of the EndoVac system can be considered to be a promising disinfection protocol, because it provided similar bacterial reduction to that of apical positive pressure irrigation (conventional irrigation) plus intracanal dressing with the triantibiotic paste, and the use of intracanal antibiotics might not be necessary., (Copyright 2010 Mosby, Inc. All rights reserved.)

Maxillary central incisors have been reported with 1, 2, and occasionally 3 root canals. The complete biomechanical instrumentation and obturation of the root canal system are mandatory to achieve endodontic success. Root canal systems with abnormal variations present a challenge in diagnosis and clinical management to the practitioner. This article presents a detailed case report of the endodontic treatment of a 3-canal maxillary incisor with an associated periodontal defect.

Introduction: This clinical study was conducted to compare the efficacy of chemomechanical preparation with 2.5% sodium hypochlorite (NaOCl) and 2% chlorhexidine (CHX) gel on eliminating oral bacterial lipopolysaccharide (LPS) in teeth with pulp necrosis and apical periodontitis., Methods: Fifty-four root canals were selected. Samples were collect before (s1) and after chemomechanical preparation (s2). Teeth were randomly divided into groups: GI, 2.5% NaOCl (n = 27) and GII, CHX gel (n = 27). Limulus amebocyte lysate assay was used to quantify endotoxins., Results: Endotoxin was present in 100% of the samples investigated, with a median value of 272 endotoxin units (EU)/mL (GI) and of 152.46 EU/mL (GII). As a result of chemomechanical preparation, LPS content was reduced to a median value of 86 EU/mL (GI) and 85 EU/mL (GII). Higher percentage value of endotoxin reduction was found in GI (P < .05)., Conclusions: The 2.5% NaOCl and 2% CHX gel were not effective in eliminating endotoxin from the primarily infected root canals.

Aims: To determine the frequency and diversity of yeasts from the dorsum of the tongue and necrotic root canals with teeth associated with primary apical periodontitis., Methodology: Detailed medical and dental histories of 168 patients were recorded. The samples were collected from the dorsum of tongue and from 168 teeth with root canals contained necrotic pulps. Yeasts were isolated on Sabouraud agar with 100 mg L(-1) chloramphenicol, purified and characterized by standard methods. Identification was confirmed by EI1 PCR fingerprint technique. Yeast isolates of uncertain identity or with a different genetic fingerprint profile from the reference strains were identified by sequencing the D1/D2 variable domains of the large subunit rDNA., Results: Yeasts were isolated from 22.6% of teeth sampled and from 45.8% of tongue samples. Candida albicans was the most frequently isolated species at both investigated sites but other species were also found. Saccharomyces cerevisiae and Kluyveromyces lactis were recovered from the tongue., Conclusions: Although the detection of yeasts in the root canal does not imply an involvement in the disease process, the study suggests a frequency of Candida spp. in primary endodontic infections that deserves further clarification.

Most mandibular first molars have 2 mesial canals. Two cases of failed endodontically treated first mandibular molars are presented with 2 obturated mesial canals. The cases were retreated with a third mesial canal identified, and instrumented and obturated with resolution of the patients' signs and symptoms. These cases show that consideration must be made to recognize the possibility of a third mesial canal and perform complete treatment to minimize the possibility of failure.

Aim: Teeth that have been weakened by caries and require root canal treatment to maintain their functional integrity may present with minimal coronal tooth structure and are a challenge for isolation and restoration. The aim of this clinical report is to demonstrate the management of badly broken down teeth using the Projector Endodontic Instrument Guidance System (PEIGS)., Summary: The PEIGS is an adjunct to root canal treatment designed to enhance the ease of treatment delivery. Use of this system facilitates projection of canal orifices from the floor of the pulp chamber to the cavosurface, providing direct visualization of and physical access to the projected canals. This report demonstrates the use of this novel device for the management of two badly broken down teeth., Key Learning Points: Use of the endodontic projection system has the following advantages: * 'Projects' the canal orifice from the floor of the pulp chamber to the cavosurface, thereby enhancing visualization and access to the canals. * The bonded coronal build up reduces the risk of interappointment crack initiation and coronal-radicular fracture of weakened tooth structure. * Permits individualization of canals especially when they lie in close proximity to each other on the chamber floor. * Isolation may be facilitated by ease of clamp retention, rendering many structurally debilitated teeth endodontically treatable.

Aim: To evaluate whether passive ultrasonic irrigation (PUI) of 2.5% NaOCl would dissolve necrotic pulp tissue from simulated accessory root canals (SACs) better than passive placement of the irrigant, when temperature was equilibrated between the two treatments., Methodology: Transparent root canal models (n = 6) were made from epoxy resin. SACs of 0.2 mm diameter were placed at defined angles and positions in the mid-canal and apical area. SACs were filled with necrotic bovine pulp tissue. PUI was performed five times for 1 min each with irrigant replenishment after every minute. Main canal temperature was measured after each minute, and a digital photograph was taken. In control experiments, mock treatments were performed with the same set-up without activation of the file using heated NaOCl to mimic the temperature created by PUI. Experiments were repeated five times. Digital photographs were analysed for the distance of dissolved tissue into the SACs in mm. Overall comparison (sum of dissolved tissue from all five accessory canals) between treatments was performed using paired t-test. Differences between SAC angulation and position after PUI were investigated using anova/Bonferroni (alpha < 0.05)., Results: Passive ultrasonic irrigation caused a rise in irrigant temperature in the main canal to 53.5 +/- 2.7 degrees C after the fifth minute. PUI dissolved a total of 6.4 +/- 2.1 mm, mock treatment controlled for heat: 1.4 +/- 0.6 mm (P < 0.05). No significant influence of SAC position or angulation was found., Conclusions: Passive ultrasonic irrigation promotes positive tissue-dissolving effects beyond a rise in irrigant temperature.

Introduction: It was the aim of the present study to evaluate root canal samples for the presence and numbers of specific species as well as for total bacterial load in teeth with chronic apical periodontitis using quantitative real-time polymerase chain reaction (PCR)., Methods: Forty adult patients with one radiographically documented periapical lesion were included. Twenty teeth presented with primary infections and 20 with secondary infections, requiring retreatment. After removal of necrotic pulp tissue or root canal filling, a first bacterial sample was obtained. Following chemo-mechanical root canal preparation a second sample was taken and a third sample was obtained after 14 days of intracanal dressing with calcium hydroxide. Analysis by real-time PCR enabled the quantification of total bacterial counts and of nine selected species., Results: Root canals with primary infections harbored significantly more bacteria (by total bacterial count) than teeth with secondary infections (P < 0.05). Mean total bacterial count in the retreatment group was 2.1 x 10(6) and was significantly reduced following root canal preparation (3.6 x 10(4)) and intracanal dressing (1.4 x 10(5)). Corresponding values for primary infections were: 4.6 x 10(7), 3.6 x 10(4), and 6.9 x 10(4). The numbers of the selected bacteria and their detection frequency were also significantly reduced., Conclusion: Root canals with primary infections contained a higher bacterial load. Chemo-mechanical root canal preparation reduced bacterial counts by at least 95%.

Background/aim: The purpose of this study was to detect bacterial species and to quantify the total number of bacteria from samples of infected root canals before (S1) and after chemo-mechanical preparation using 2% chlorhexidine (CHX) gel as auxiliary chemical substance (S2) and after 7 days of intracanal dressing (S3) to compare microbial changes., Method: Twenty-four teeth were selected for this study. Chemo-mechanical preparation was performed using 2% CHX gel, then three different intracanal medicaments [M1: Ca(OH)(2) paste; M2: 2% CHX gel; and M3: Ca(OH)(2) paste plus 2% CHX gel] were used for 7 days. Checkerboard DNA-DNA hybridization was performed to detect 40 bacterial species. Aerobic and anaerobic culture techniques were used to determine the bacterial community by counting the colony-forming units (CFU)., Results: The species most frequently identified by checkerboard in S1 were: Fusobacterium nucleatum ssp. polymorphum, Treponema socranskii ssp. socranskii, Parvimonas micra and Enterococcus faecalis. In S2 and S3 a total of eight different species were identified; and only one of them was gram-positive (E. faecalis). Microorganisms were not identified after use of M2 for 7 days. The quantification obtained on agar plates ranged from 4 x 10(5) to 2.6 x 10(6) CFU/ml in S1, mean CFU was reduced by 99.96% in S2, and there was no statistical difference between the CFU in S2 and S3., Conclusion: The antibacterial effect of the mechanical preparation supplemented by the use of an antibacterial auxiliary substance greatly reduced the microorganisms in the main root canal.