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1.  Detection of Enterococcus faecalis and Candida albicans in previously root-filled teeth in a population of Gujarat with polymerase chain reaction 
Background:
Micro-organisms are the primary causative agents of endodontic infections. Phenotype based procedures for bacterial identification has certain drawbacks especially, when investigating the microbiota of root-filled teeth. Thus, more sensitive methods like Polymerase chain reaction (PCR) can provide results that are more accurate and reliable for the microbial prevalence in the root filled teeth.
Aim:
In this study, we have investigated twenty symptomatic root-filled teeth with chronic apical periodontitis for the prevalence of Enterococcus faecalis and Candida albicans in the root filled teeth associated with symptomatic cases with or without periradicular lesions.
Materials and Methods:
Microbiological samples were taken from the canals immediately after removal of previous gutta percha cones using aseptic techniques. After removal of root canal filling, samples were obtained with paper points placed in the canal. Paper points were transferred to a cryotube containing “Tris EDTA” buffer and immediately frozen at −20°C.
Results:
By PCR amplification of the samples using taxon specific primers, E. faecalis was found to be prevalent species, detected in 65% of the cases and C. albicans was detected in 35% of cases.
Conclusion:
The results of the study shows that geographical influence and dietary factors might have some role to play in the prevalence of the species like C. albicans and presence of E. faecalis confirming the assertion of previous culture-dependent and independent approaches for the microbiological survey of root filled teeth.
doi:10.4103/0976-237X.111622
PMCID: PMC3703696  PMID: 23853454
Candida albicans; Enterococcus faecalis; polymerase chain reaction; root filled teeth
2.  Microbial Flora of Root Canals of Pulpally-infected Teeth: Enterococcus faecalis a Prevalent Species 
Background and aims
The aim of this study was to determine the microorganisms prevalent in the necrotic dental pulp and root canals of unsuccessfully treated teeth.
Materials and methods
The present study was conducted on 150 single-rooted teeth of patients referring to a dental clinic. Sampling was performed by placing a sterile paper point in the canal for 60 s. Bacterial samples were evaluated by a microbiological technique specific for anaerobic species, used for isolation and identification of sampled strains.
Results
From the 150 samples taken, 101 were from necrotic pulps (primary infection) and 49 were from the teeth with an unsuccessful endodontic treatment (secondary infection).
Conclusion
Enterococcus faecalis was a prevalent species in the failed root canals evaluated.
doi:10.5681/joddd.2009.007
PMCID: PMC3517199
Endodontic therapy; Enterococcus faecalis; failure
3.  Endodontic treatment enhances the regenerative potential of teeth with advanced periodontal disease with secondary endodontic involvement 
Purpose
The aim of this study was to identify a role for endodontic intervention in enhancing the regenerative potential of the periodontal ligament when combined with periodontal treatment in seriously involved teeth with a secondary endodontic component.
Methods
Patients who exhibited radiolucency extending to the periapical region, abnormal electric pulp testing values, and deep probing depth derived from primary periodontal disease with secondary endodontic involvement were included. Intentional root canal treatment was applied to those teeth in which the apical lesions were presumed to communicate with those of the periodontal lesion of the teeth that remained vital. In all three selected cases, regenerative periodontal therapy incorporating either bone graft or guided tissue regeneration was instituted 3 months after the endodontic intervention.
Results
Remarkable enhancement in radiographic density was noticeable around the affected teeth as evidenced by changes in radiopacity. There was a significant reduction in the probing pocket depth and gain in the clinical attachment level. Chewing discomfort gradually disappeared from the commencement of the combined treatment.
Conclusions
An intentional endodontic intervention may be a worthwhile approach for the sophisticated management of teeth suffering from serious attachment loss and alveolar bone destruction with concomitant secondary endodontic involvement.
doi:10.5051/jpis.2013.43.3.136
PMCID: PMC3701835  PMID: 23837128
Periodontal attachment loss; Periodontal disease; Root canal therapy
4.  Searching for Helicobacter pylori and Chlamydia pneumoniae in primary endodontic infections 
European Journal of Dentistry  2012;6(2):158-162.
Objectives:
The purpose of this study was to search samples from primary endodontic infections for the presence of two common human bacterial pathogens - Helicobacter pylori and Chlamydia pneumoniae.
Methods:
Genomic DNA isolated from samples taken from 25 root canals of teeth with asymptomatic (chronic) apical periodontitis and 25 aspirates from acute apical abscess was initially amplified by the multiple displacement amplification approach and then used as template in species-specific polymerase chain reaction (PCR) for detection of H. pylori and C. pneumoniae.
Results:
All clinical samples were positive for the presence of bacterial DNA. However, no clinical sample was positive for either H. pylori or C. pneumoniae.
Conclusions:
Neither H. pylori nor C. pneumoniae were found in samples from primary endodontic infections. These findings suggest that these species are not candidate endodontic pathogens and that the necrotic root canal does not serve as a reservoir for these human pathogens in healthy patients.
PMCID: PMC3327501  PMID: 22509118
Helicobacter pylori; Chlamydia pneumoniae; apical periodontitis; acute apical abscess; polymerase chain reaction
5.  Polymerase chain reaction of enterococcus faecalis and candida albicans in apical periodontitis from Turkish patients 
Aim: The aim of this study was to determine the frequency of two important pathogenic microorganisms associated with endodontic infections, Enterococcus faecalis and Candida albicans, in root canal samples from patients with necrotic pulps or failed canal therapy by polymerase chain reaction method. Method: Microbial samples were obtained from 117 teeth with necrotic pulp tissues and 114 teeth with failed endodontic treatment. Results: E.faecalis were identified in 16% of the necrotic and 10% of the retreated root canal infections by PCR. C.albicans genome were identified in 20% and 11% of the necrotic and retreated root canal infections, respectively, by PCR. The frequencies of microbiota were not statistically different between necrotic and retreatment groups (p > 0.05, chi squared test). Conclusions: PCR analysis of teeth with periapical lesions revealed that E.faecalis was found in fewer patients than in previous studies. The C.albicans prevelance was consistent with previous reports. No statistical difference was found between primary and secondary root canal infections for C.albicans or E.faecalis.
Key words:Primary root canal infection, secondary root canal infection, E.faecalis, C.albicans.
doi:10.4317/jced.50669
PMCID: PMC3908807  PMID: 24558522
6.  Detection of Treponema Denticola in Symptomatic Apical Periodontitis and in Symptomatic Apical Abscesses by Real-Time PCR 
European Journal of Dentistry  2009;3(2):107-113.
Objectives:
The aim of this study was to investigate the presence of Treponema denticola in symptomatic apical periodontitis and in symptomatic apical abscesses by real-time polymerase chain reaction (PCR) method.
Methods:
Microbial samples were collected from 60 single-rooted teeth having carious lesions and necrotic pulps. For each tooth, clinical data including patient symptoms were recorded. Teeth were categorized by diagnosis as having symptomatic apical periodontitis or symptomatic apical abscess. Aseptic microbial samples were collected using paper points from 30 infected root canals and from aspirates of 30 abscesses. DNA was extracted from the samples by using a QIAamp® DNA mini-kit and analyzed with real-time PCR.
Results:
T. denticola was detected in 24 of 30 cases diagnosed as symptomatic apical abscesses (80%), and 19 of 30 cases diagnosed as symptomatic apical periodontitis (63.3%). In general T. denticola was found in 43 of 60 cases (71.6%).
Conclusions:
Our findings suggest that T. denticola can participate in the pathogenesis of symptomatic apical abscesses.
PMCID: PMC2676069  PMID: 19421390
Treponema denticola; Symptomatic apical abscess; Necrotic tooth; Root canal; Real-time PCR
7.  Clinical and Radiographic Evaluation of Success Rate with MTA Plug in Open Apices 
Iranian Endodontic Journal  2006;1(1):15-18.
INTRODUCTION: The ideal endodontic treatment for the teeth with in complete root-ends and necrotic pulps may involve the use of material which forms an immediate apical barrier instead of long term calcium hydroxide therapy. Such procedure may lead us to a single appointment endodontic treatment. The purpose of the present study was to evaluate clinical and radiographic success rate in necrotic teeth with open apices treated with MTA as an apical plug.
MATERIALS AND METHODS: Thirty five patients between the ages of 8-16 with total number of 41 necrotic anterior teeth containing open apices were selected. In the first visit, root canals were debrided and filled with calcium hydroxide. After one week, calcium hydroxide was removed and MTA with the thickness of 3 to 4 mm was put in the apical region of the canals. After 24 hours, the remaining part of the canals was filled with guttapercha and sealer and the teeth were restored with composite. All the cases were evaluated clinically and radiographically after 3 and 6 months and data were analyzed by McNemar test.
RESULTS: No clinical symptoms were observed in 97.6% of the teeth after 3 months and in none after 6 months. The study showed a significant difference from pretreatment status. After 3 months radiographic evaluation showed that in 17 cases (41.5%), lesions were reduced and in 14 cases (34.1 %), lesions remained the same, and in 10 cases (24.4%) lesions disappeared. After 6 months in 21 cases (51.2%), lesions were reduced, in 3 cases (7.3%) lesions remained the same and in 17 cases (41.5%) lesions disappeared. These finding were statistically different from pretreatment data.
CONCLUSION: The results indicate that MTA can be used as an apical plug in the teeth with open apices following root canal debridement and disinfection with calcium hydroxide. Further investigations with longer follow-ups are recommended in order to evaluate the effect of this material.
PMCID: PMC3909610  PMID: 24494020
Apical Plug; Calcium Hydroxide; MTA; Open Apex
8.  Metaproteome Analysis of Endodontic Infections in Association with Different Clinical Conditions 
PLoS ONE  2013;8(10):e76108.
Analysis of the metaproteome of microbial communities is important to provide an insight of community physiology and pathogenicity. This study evaluated the metaproteome of endodontic infections associated with acute apical abscesses and asymptomatic apical periodontitis lesions. Proteins persisting or expressed after root canal treatment were also evaluated. Finally, human proteins associated with these infections were identified. Samples were taken from root canals of teeth with asymptomatic apical periodontitis before and after chemomechanical treatment using either NaOCl or chlorhexidine as the irrigant. Samples from abscesses were taken by aspiration of the purulent exudate. Clinical samples were processed for analysis of the exoproteome by using two complementary mass spectrometry platforms: nanoflow liquid chromatography coupled with linear ion trap quadrupole Velos Orbitrap and liquid chromatography-quadrupole time-of-flight. A total of 308 proteins of microbial origin were identified. The number of proteins in abscesses was higher than in asymptomatic cases. In canals irrigated with chlorhexidine, the number of identified proteins decreased substantially, while in the NaOCl group the number of proteins increased. The large majority of microbial proteins found in endodontic samples were related to metabolic and housekeeping processes, including protein synthesis, energy metabolism and DNA processes. Moreover, several other proteins related to pathogenicity and resistance/survival were found, including proteins involved with adhesion, biofilm formation and antibiotic resistance, stress proteins, exotoxins, invasins, proteases and endopeptidases (mostly in abscesses), and an archaeal protein linked to methane production. The majority of human proteins detected were related to cellular processes and metabolism, as well as immune defense. Interrogation of the metaproteome of endodontic microbial communities provides information on the physiology and pathogenicity of the community at the time of sampling. There is a growing need for expanded and more curated protein databases that permit more accurate identifications of proteins in metaproteomic studies.
doi:10.1371/journal.pone.0076108
PMCID: PMC3797121  PMID: 24143178
9.  CBVT analysis of canal configuration of the mesio-buccal root of maxillary first permanent molar teeth: An in vitro study 
Contemporary Clinical Dentistry  2012;3(3):277-281.
Context:
For successful endodontic treatment, it's imperative to locate and obturate all root canals. As concluded by Ingle, the major cause for failure of root canal therapy is in ability to recognize all theexisting canals and subsequent failure in their obturation.
Aim:
To analyze the canal configuration of the mesio-buccal root of maxillary first permanent molar teeth.
Materials and Methods:
A total of 30 recently extracted human permanent maxillary first molars were collected and stored in a container with 5% Sodium Chloride solution for four days. Teeth with open apices, external resorption, improperly formed roots and teeth with previous restorations were excluded. Using the dental modeling wax, teeth were arranged in a ‘U’ shaped arch with roots embedded inside the wax and occlusal surface remaining free. 10 teeth were arranged in each arch and three such sample plates were prepared. Flat surface of the base encasing enabled the plate to be mounted on flat plastic bite plate. With bite plate roughly centered in the focal trough area Axial, Coronal and Sagittal section Cone-Beam Computed Tomography (CBCT) images were taken with Kodak 9000 Extra-oral Imaging System. Images displayed on a monitor were inspected by two endodontists using Kodak Dental Imaging Software 3D Module V2.2.
Statistical Analysis:
When the data was observed, it was found that 24 teeth out of total 30 teeth examined showed some variation (i.e. possible additional canal) along the length of the mesio-buccal root canal. Out of these 24 teeth, 13 showed presence of additional canal at coronal third, 7 showed presence of additional canal at middle third and four showed presence of additional canal in apical third level. Percentage analysis was done as there was no group comparison to be done.
Results:
Cone-Beam Volumetric Tomography (CBVT) evaluation positively identified the variations in mesio-buccal canal in 80% of samples. Out of these, 54.16% were in coronal 3rd, 29.16% in middle 3rd and 16.66% were in apical 3rd.
Conclusion:
Within the limitations of this study, it can be concluded that- (1) more than half of maxillary first molars have four canals and (2) most of the additional canals were located in the MBR and CBVT is a good diagnostic tool to help diagnose these additional canals. Further investigations using larger sample sizes would be helpful.
doi:10.4103/0976-237X.103618
PMCID: PMC3532788  PMID: 23293481
Cone-beam computed tomography; cone beam projection geometry; MB2 canal; root canal system
10.  Comparison of Endodontic Treatment Results Yielded from Using Normal Saline with IKI Final Rinse or NaOCl Irrigation: A 30-Month Follow-up Study 
Iranian Endodontic Journal  2013;8(4):171-176.
Introduction
The aim of this clinical trial was to evaluate and compare the endodontic treatment results of teeth with apical periodontitis after thirty-month recall with two different irrigation regimen: normal saline followed by Iodine Potassium Iodide (IKI) or sodium hypochlorite (NaOCl) irrigation alone.
Materials and Methods
Twenty seven patients (30 teeth) who had been included in the first part of our antimicrobial survey were recalled. In previous stage, root canal treatments were performed using either normal saline with IKI final rinse (n = 15) or NaOCl (n = 15) as irrigating solutions. Bacterial samples were taken before and after instrumentation. In this stage, three patients (6 teeth) were excluded from the follow-up schedule since they did not respond to the recall requests. The remaining 24 subjects (12 teeth in each NaOCl and IKI group) were examined clinically and radiologically. Post-operative and follow-up images were coded, blindly evaluated and given a periapical score according to PAI scoring system. The outcome was assessed in two ways; first, the changes in PAI score from base line to the follow-up evaluation in each group were assessed by wilcoxon signed rank test. In addition, Mann-Whitney U test was used to compare the differences between the post-operative and follow-up images of treatment groups. Second, the dichotomous variables as “healed” or “not healed” were compared.
Results
The Median (Min, Max) PAI scores for NaOCl group and IKI group were both 5 (3, 5) for immediate post-operative radiographs and declined to 1 (1, 2) and 2 (1, 2), respectively. A statistically significant decrease in PAI score from the base line to the follow-up evaluation was seen in both groups (P = 0.002). The decrease in NaOCl group was higher significantly in comparison to IKI group (P = 0.036). One hundred percent of the teeth were healed in both groups (PAI ≤ 2) and no teeth showed any abnormal clinical findings.
Conclusion
Root canal irrigation with NaOCl resulted in a significant higher decrease in PAI scores in comparison to irrigation with normal saline followed by IKI final rinse. Although, according to results of 30-months recall, complete bone formation was observed in all samples in both groups and no teeth showed any abnormal clinical findings. These findings depict the weight of all important clinical and biological factors which together impact the results of a successful endodontic treatment.
PMCID: PMC3808676  PMID: 24171024
Apical Periodontitis; Healing; Iodine Potassium Iodide; Sodium Hypochlorite
11.  Distinctive features of the microbiota associated with different forms of apical periodontitis 
Journal of Oral Microbiology  2009;1:10.3402/jom.v1i0.2009.
Microorganisms infecting the dental root canal system play an unequivocal role as causative agents of apical periodontitis. Although fungi, archaea, and viruses have been found in association with some forms of apical periodontitis, bacteria are the main microbial etiologic agents of this disease. Bacteria colonizing the root canal are usually organized in communities similar to biofilm structures. Culture and molecular biology technologies have demonstrated that the endodontic bacterial communities vary in species richness and abundance depending on the different types of infection and different forms of apical periodontitis. This review paper highlights the distinctive features of the endodontic microbiota associated with diverse clinical conditions.
doi:10.3402/jom.v1i0.2009
PMCID: PMC3077003  PMID: 21523208
endodontic infection; acute apical abscess; endodontic pathogens; biofilm
12.  Comparison of Antimicrobial Efficacy of IKI and NaOCl Irrigants in Infected Root Canals: An In Vivo Study 
Iranian Endodontic Journal  2010;5(3):101-106.
INTRODUCTION
Effective debridement of the root canal system with chemical irrigants prior to obturation is the key to long-term success of endodontic therapy. The purpose of this study is to compare the antibacterial activity of 2.5% sodium hypochlorite (NaOCl) and 2% iodine potassium iodide (IKI) solutions as intracanal disinfectant in infected root canals during one-visit endodontic treatment procedure.
MATERIALS AND METHODS
Thirty single-rooted teeth with necrotic pulps in 27 patients were selected according to specific inclusion/exclusion criteria and divided into two random groups. In group I, canals were irrigated with 2.5% NaOCl during instrumentation and in group II canals were initially irrigated with sterile saline during biomechanical preparation and then exposed to a 5-minute final irrigation with 2% IKI. Bacterial samples were taken before treatment (S1), and at the end of treatment (S2). Mann-Whitney U test was used for analysis.
RESULTS
Bacteria were present in all initial samples. NaOCl was able to significantly reduce the number of colony forming units (CFU) from S1 to S2 in approximately 90% of canals. Only 15% reductions in CFUs occurred after irrigation/instrumentation in group II; this degree of disinfection was not statistically significant.
CONCLUSION
According to this study, although root canal irrigation with 2.5% NaOCl could not eradicate all bacteria within the canals; it was significantly superior in comparison with 2% IKI use.
PMCID: PMC3471579  PMID: 23130035
Antibacterial; Iodine Potassium Iodide; Root Canal Irrigants; Sodium Hypochlorite
13.  Capacity of anaerobic bacteria from necrotic dental pulps to induce purulent infections. 
Infection and Immunity  1979;25(2):685-693.
Combinations of bacteria isolated from the root canals of teeth with necrotic pulps and periapical bone destruction were tested for their capacity to induce abscess formation and transmissible infections when inoculated subcutaneously into guinea pigs. Transmissible infections could be induced with combinations obtained from teeth with purulent apical inflammation, but not with combinations from symptomless teeth with chronic apical inflammation. All combinations which gave transmissible infections contained strains of Bacteroides melaninogenicus or B. asaccharolyticus (formerly B. melaninogenicus subsp. asaccharolyticus). The results suggest that purulent inflammation in the apical region in certain cases may be induced by specific combinations of bacteria in the root canal and that the presence of B. melaninogenicus or B. asaccharolyticus in such combinations is essential. However, with one exception, the strains needed the support of additional microorganisms to achieve pathogenicity. The results indicate that Peptostreptococcus micros was also essential. Histological sections of the lesions in the guinea pigs showed that all bacterial combinations induced acute inflammation with an accumulation of polymorphonuclear leukocytes and the formation of an abscess. However, the presence of B. melaninogenicus or B. asaccharolyticus in the combinations resulted in a failure of abscess resolution, with a gradually increaseing accumulation of polymorphonuclear leukocytes.
Images
PMCID: PMC414499  PMID: 489126
14.  Microbiota of deciduous endodontic infections analyzed by MDA and Checkerboard DNA-DNA hybridization 
International endodontic journal  2010;44(3):225-235.
Aims
To evaluate the microbiota of endodontic infections in deciduous teeth by checkerboard DNA-DNA hybridization after uniform amplification of DNA in samples by multiple displacement amplification (MDA).
Methodology
Forty samples from the root canal system of deciduous teeth exhibiting pulp necrosis with or without radiographically detectable periradicular/interadicular bone resorption were collected and 32 were analyzed, with 3 individuals contributing 2 samples; these were MDA- amplified and analyzed by Checkerboard DNA-DNA hybridization for levels of 83 bacterial taxa. Two outcome measures were used: the percentage of teeth colonized by each species; and the mean proportion of each bacterial taxon present across all samples were computed.
Results
The mean amount of DNA in the samples prior to amplification was 5.2 (± 4.7) ng and 6.1 (± 2.3) μg after MDA. The mean number of species detected per sample was 19 (± 4) (range: 3–66) to the nearest whole number. The most prevalent taxa were Prevotella intermedia (96.9%), Neisseria mucosa (65.6%), Prevotella nigrescens (56.2%) and Tannerella forsythia (56.2%). Aggregatibacter (Haemophilus) aphrophilus and Helicobacter pylori were not detected. P. intermedia (10%), Prevotella tannerae (7%) and Prevotella nigrescens (4.3%) presented the highest mean proportions of the target species averaged across the positive samples.
Conclusion
Root canals of infected deciduous teeth had a diverse bacterial population. Prevotella sp were commonly found with P. intermedia, Prevotella tannerae and Prevotella nigrescens among the most prominent species detected.
doi:10.1111/j.1365-2591.2010.01805.x
PMCID: PMC3177302  PMID: 21083570
15.  Success Rate of Nonsurgical Endodontic Treatment of Nonvital Teeth with Variable Periradicular Lesions 
Iranian Endodontic Journal  2011;6(3):119-124.
INTRODUCTION
Bacterial infection of tooth pulp can progress into periapical diseases. Root canal treatment has been established as the best treatment. In cases of failure, nonsurgical retreatment of teeth is preferred to surgical procedure and extraction.
MATERIALS AND METHODS
In this historical cohort study, 104 permanent teeth with apical lesion were treated during 2002-2008. All teeth showed radiographic evidence of periapical lesion varying in size from 1 to >10mm. A total of 55 teeth were treated with initial root canal treatment and 49 teeth required retreatment. Patients were recalled up to ≈7 years. All radiographs were taken by RSV MAC digital imaging set and long cone technique. The presence/absence of signs and symptoms and periapical index scores (PAI) were used for measuring outcome. Teeth were classified as healed (clinical/radiographic absence of signs and symptoms) or diseased (clinical/radiographic presence of signs and symptoms). The data were statistically analyzed using student t-test and Pearson chi-square or fisher’s exact test.
RESULTS
The rate of complete healing for teeth with initial treatment was 89.7%, and for retreatment group was 85.7%; there was no significant difference. Size of lesions did not significantly affect the treatment outcomes. Success of tooth treatment did not reveal significant correlation with gender and number of roots.
CONCLUSION
Orthograde endodontic treatment/retreatment demonstrates favorable outcomes. Thus, nonsurgical endodontic treatment/retreatment should be considered as the first choice in teeth with large periapical lesion.
PMCID: PMC3487520  PMID: 23130063
Endodontics; Periapical Disease; Retreatment; Root Canal Therapy; Treatment Outcome
16.  Prevalence of Enterococcus faecalis in saliva and filled root canals of teeth associated with apical periodontitis 
To investigate the prevalence of Enterococcus faecalis in saliva and filled root canals of patients requiring endodontic retreatment for apical periodontitis. Patients with apical periodontitis who were referred for endodontic retreatment were examined. The type and quality of the restoration, symptoms, quality of obturation were recorded. During retreatment, an oral rinse sample and root canal sample were cultured using brain-heart infusion agar and bile esculinazide agar to select for E. faecalis. The 16S rRNA technique was used to identify E. faecalis. A total of 32 women and 22 men (mean age: 38 years; s.d.: 11 years) and 58 teeth were studied. The prevalence of E. faecalis was 19% in the saliva and 38% in the root canals. The odds that root canals harbored E. faecalis were increased if the saliva habored this bacterium (odds ratio=9.7; 95% confidence interval=1.8–51.6; P<0.05). Teeth with unsatisfactory root obturation had more cultivable bacterial species in root canals than teeth with satisfactory root obturation (P<0.05). E. faecalis is more common in root canals of teeth with apical periodontitis than in saliva. The prevalence of E. faecalis in root canals is associated with the presence of E. faecalis in saliva.
doi:10.1038/ijos.2012.17
PMCID: PMC3412659  PMID: 22422085
apical periodontitis; endodontic treatment; Enterococcus faecalis; saliva; 16S rRNA
17.  Influence of the apical enlargement size on the endotoxin level reduction of dental root canals 
Journal of Applied Oral Science  2012;20(6):661-666.
Gram-negative bacteria play an essential role in endodontic infections because they have virulence factors such as endotoxin. Due to its potential cytotoxic activity, special attention has been given to the removal/neutralization of this endotoxin in the root canal system.
Objective
The aim of this study was to evaluate the influence of the apical enlargement size (AES) by using rotary instruments on the endotoxin level reduction of dental root canals.
Material and Methods
Forty root canals of the mandibular premolar teeth were used. Escherichia coli endotoxin (055: B55) was inoculated into thirty root canals. Ten teeth served as the negative control group. After the incubation period, the first endotoxin samples were collected from the root canals with a sterile/apyrogenic paper point for the analysis of the endotoxin units (EU/mL) present before instrumentation (S1). Specimen instrumentation was performed with the Mtwo® rotary system in the sequence 10/.04, 15/.05, 20/.06, 25/.06, 30/.05, 35/.04 and 40/.04. To monitor the effectiveness of increasing apical enlargement on endotoxin removal, the second endotoxin samples were collected from all the root canals after instrumentation with the following instruments: #25/.06- (S2); #30/.05- (S3); # 35/.04- (S4); and #40/.04- (S5). Limulus amebocyte lysate (LAL) was used to quantify the levels of endotoxin. The results were statistically compared by using repeated measures of ANOVA with post hoc Tukey testing.
Results
Increasing levels of endotoxin removal was achieved by large sized apical enlargement: S2 (AES #25/.06)- 89.2%, S3 (AES #30/.05)- 95.9%, S4 (AES #35/.04)- 97.8% and S5 (AES #40/.04)- 98.2%. Substantial reduction of endotoxin content was obtained in S4 and S5 compared to S2 (p<0.05), however, the root canal preparation was not able to eliminate the endotoxin.
Conclusions
Under the conditions of this study, it was concluded that the reduction of endotoxin levels of the dental root canals could be predicted by increasing the apical enlargement size.
doi:10.1590/S1678-77572012000600012
PMCID: PMC3881856  PMID: 23329249
Root canal; Bacterial infections; Instrumentation
18.  Matrix Metalloproteinase Expression in Teeth with Apical Periodontitis Is Differentially Modulated by the Modality of Root Canal Treatment 
Journal of endodontics  2010;36(2):231.
Objectives
To investigate the expression of matrix metalloproteinases (MMPs) in apical periodontitis and during the periapical healing phase following root canal treatment.
Methods
Apical periodontitis was induced in dog teeth and root canal treatment was performed in a single visit or using an additional calcium hydroxide root canal dressing. One hundred and eighty days following treatment the presence of inflammation was examined and tissues were stained to detect bacteria. Bacterial status was correlated to the degree of tissue organization, and to further investigate molecules involved in this process, tissues were stained for MMP-1, MMP-2, MMP-8, and MMP-9. Data were analyzed using one-way ANOVA followed by Tukey test or Kruskal-Wallis followed by Dunn.
Results
Teeth with apical periodontitis that had root canal therapy performed in a single visit presented an intense inflammatory cell infiltrate. Periapical tissue was extremely disorganized, and this was correlated with the presence of bacteria. Higher MMP expression was evident, similar to teeth with untreated apical periodontitis. In contrast, teeth with apical periodontitis submitted to root canal treatment using calcium hydroxide presented a lower inflammatory cell infiltrate. This group had a moderately organized connective tissue, a lower prevalence of bacteria, and a lower number of MMP-positive cells, similar to healthy teeth submitted to treatment.
Conclusion
Teeth treated with calcium hydroxide root canal dressing exhibited a lower percentage of bacterial contamination, a lower MMP expression, and a more organized ECM, unlike those treated in a single visit. This suggests that calcium hydroxide may be beneficial in tissue repair processes.
doi:10.1016/j.joen.2009.10.030
PMCID: PMC2818380  PMID: 20113780
apical periodontitis; root canal treatment; single visit; calcium hydroxide; matrix metalloproteinases
19.  Root and Canal Morphology of Mandibular Second Molar in an Iranian Population by Clearing Method 
Journal of Dentistry  2013;14(2):78-81.
Statement of Problem: The knowledge of the pulp anatomy plays an important role in the success of endodontic treatments.
Purpose: The aim of this study was to determine the root and canal morphology of the mandibular second molar teeth in an Iranian population.
Material and Methods: One hundred intact human mandibular second molars were collected. The teeth were examined visually and the number of their roots were recorded. The teeth were covered using of lacquer. Access cavities were prepared and the pulp tissue was dissolved by sodium hypochlorite. The apices were covered with the glue and the root canals were injected with the methylene blue and were decalcified with 10% nitric acid, dehydrated with ascending concentrations of alcohol and rendered clear by immersion in methyl salicylate. The following remarks were evaluated: (i) number of root canals per tooth; (ii) number of canals per root; (iii) canal configuration in each root.
Results: Of 100 examined teeth; 6% had one root, 89% had two roots, 2% had three roots and 3% had C-shaped roots. The teeth were classified based on the number of canals: 3 % had single canal, 6 % two canals, 54% three canals, 34% four canals, whilst 3 % had C-shaped roots. Based on the Vertucci classification, the most prevalent canal configuration in the mesial root was type II and in the distal root was type I.
Conclusion : Iranian mandibular second molar teeth exhibit features which are similar to the average Jordanian, Caucasian and Burmese root and canal morphology.
PMCID: PMC3977544  PMID: 24724124
Canal Morphology; Mandibular Second Molar; Clearing; Iranian Population
20.  Apexification with a New Intra-Canal Medicament: A Multidisciplinary Case Report 
Iranian Endodontic Journal  2012;7(3):165-170.
Dental trauma generally requires multidisciplinary planning and treatment for good prognosis. When immature teeth are traumatized to a degree where pulp necrosis ensues, the objective of root canal treatment should be apexogenesis and root maturation. Apexification of the root is the conventional choice, which involves cleaning the canal and filling it with a temporary medication that stimulates the formation of a calcific apical barrier. Dental Trauma Service of Piracicaba Dental School, State University of Campinas (UNICAMP), Brazil employs a dressing for apexification treatments with calcium hydroxide, chlorhexidine gel 2% and zinc oxide. This paper reports the case of a dental trauma of the maxillary central incisors and subluxation on teeth 11, 12 and 21 that were treated with multidisciplinary collaboration (Endodontics, Periodontology and Operative Dentistry) to improve prognosis. After five-years there were no pathological conditions and the teeth showed every evidences of success.
PMCID: PMC3467138  PMID: 23056138
Apexification; Endodontics; Calcium Hydroxide; Periodontics; Tooth Injuries
21.  Effect of Previous Calcium Hydroxide Dressing on the Sealing Properties of the New Endodontic Cement Apical Barrier 
European Journal of Dentistry  2011;5(3):260-264.
Objectives:
Using the fluid filtration method, an in vitro study was conducted to evaluate the effects of medication with calcium hydroxide on the sealing ability of the New Endodontic Cement (NEC) apical barrier in the short and long terms.
Methods:
Fifty extracted single rooted teeth were prepared and apical resorption produced using acid sulfuric for four days. The teeth were randomly divided into two experimental groups (n=20) and two control groups. In group 1, calcium hydroxide was placed into all canals for one week and in group 2, no medication was used. In both groups, a 4 mm NEC apical plug was placed in the canals and the remaining portion of the canals was filled with gutta-percha. The amount of microleakage of all samples was evaluated after one week and three months. The data were statistically analyzed using two-way ANOVA.
Results:
There was no significant difference between the two groups in either time period (P>.05). In both group 1 and group 2, microleakage increased after three months but this increase was not statistically significant (P>.05).
Conclusions:
According to the result of this study, medication with calcium hydroxide had no adverse effect on the short- and long-term sealing properties of an NEC apical plug.
PMCID: PMC3137438  PMID: 21769266
Calcium hydroxide; Apical barrier; Leakage; Fluid filtration; New Endodontic Cement
22.  Impact of the quality of coronal restoration versus the quality of root canal fillings on success of root canal treatment: a systematic review and meta-analysis 
Journal of endodontics  2011;37(7):10.1016/j.joen.2011.04.002.
Introduction
Thorough cleaning and shaping of root canals are essential for periapical healing. Restoration of endodontically-treated teeth is also required for them to function and prevent coronal leakage. This study compared the impact of the quality of root canal treatment versus the quality of coronal restoration in treatment outcomes.
Methods
Literature search was conducted using the search terms “coronal restoration”, “root canal”, “periapical status” and “quality”. Articles that evaluated the effect of the quality of root filling and coronal restoration or both on the success of root canal treatment were selected. Nine articles were identified and were reviewed by three investigators. Data were collected based on pre-determined criteria. Percentages of teeth without apical periodontitis were recorded for each category: Adequate Root Canal Treatment (AE), Inadequate Root Canal Treatment (IE), Adequate Restoration (AR), Inadequate Restoration (IR). Data were analyzed using meta-analysis for odds ratios (ORs).
Results
After adjusting for significant covariates to reduce heterogeneity, the results were combined to obtain pooled estimates of the common OR for the comparison of AR/AE vs AR/IE (OR 2.734; 95% CI 2.61–2.88; p<0.001) and AR/AE vs IR/AE (OR 2.808; 95% CI 2.64–2.97; p<0.001).
Conclusion
On the basis of the current best available evidence, the odds for healing of apical periodontitis increase with both adequate root canal treatment and adequate restorative treatment. Although poorer clinical outcomes may be expected with adequate root filling-inadequate coronal restoration and inadequate root filling-adequate coronal restoration, there is no significant difference in the odds of healing between these two combinations.
doi:10.1016/j.joen.2011.04.002
PMCID: PMC3815527  PMID: 21689541
coronal restoration; meta-analysis; obturation; periapical status; quality; root canal treatment; systematic review
23.  Periapical Status and Quality of Root canal Fillings and Coronal Restorations in Iranian Population 
Iranian Endodontic Journal  2010;5(2):74-82.
INTRODUCTION
This cross-sectional survey determined the dental prevalence of apical periodontitis (AP) in selected Iranian population, and evaluated the influence of the quality of root canal treatment (RCT) and their coronal restorations (CR) on the periapical status.
MATERIALS AND METHODS
A total of 1064 panoramic radiographies were evaluated by two observers during 2009. The quality of RCT i.e. length/density of root fillings and CR in addition to periapical status of endodontically treated teeth were recorded. Their interrelationship was analyzed by Chi-squared, logistic regression and Spearman's rho statistics. Hosmer and Lemeshow tests were used for assessing fitness of logistic regression model and one sample k-s test was used for evaluating of normality of the data.
RESULTS
Our results showed that 527 teeth (52%) of the endodontically treated teeth presented with AP radiographically. The percentages of teeth which fulfilled the criteria of an acceptable RCT or CR radiographically were 42.3 and 62.5 respectively. Incidence of AP among teeth with acceptable RCT (29.1%) was significantly lower than those suffering from unacceptable RCT (68.8%) (P<0.001). Moreover, adequate CR demonstrated a significantly better periapical status (58.6%) compared to teeth with inadequate CR (30.3%) (P<0.001). The incidence of AP ranged from 25.6% (good qualities) to 79.5% (bad qualities) (P<0.001). Cases with both unacceptable RCT/CR were 11 times more likely to have AP than cases with acceptable RCT/CR. The quality of RCT and CR were found to impact the periapical health of endodontically treated teeth.
CONCLUSION
There are a significant high number of technically unacceptable endodontic and restorative treatments in Iran; therefore considerable efforts are needed to improve the standards of endodontic and restorative treatments.
PMCID: PMC3487502  PMID: 23130031
Apical Periodontitis; Coronal Restoration; Endodontic Outcomes; Epidemiology; Root Fillings
24.  Root Canal Microbiota of Teeth with Chronic Apical Periodontitis▿ † 
Journal of Clinical Microbiology  2008;46(11):3599-3606.
Samples from infected root canals of 43 teeth with chronic apical periodontitis were analyzed for the presence and relative levels of 83 oral bacterial species and/or phylotypes using a reverse-capture checkerboard hybridization assay. Associations between the most frequently detected taxa were also recorded. The most prevalent taxa were Olsenella uli (74%), Eikenella corrodens (63%), Porphyromonas endodontalis (56%), Peptostreptococcus anaerobius (54%), and Bacteroidetes oral clone X083 (51%). When prevalence was considered only for bacteria present at levels >105, Bacteroidetes clone X083 was the most frequently isolated bacterium (37%), followed by Parvimonas micra (28%), E. corrodens (23%), and Tannerella forsythia (19%). The number of target taxa per canal was directly proportional to the size of the apical periodontitis lesion, with lesions >10 mm in diameter harboring a mean number of approximately 20 taxa. Several positive associations for the most prevalent taxa were disclosed for the first time and may have important ecological and pathogenic implications. In addition to strengthening the association of several cultivable named species with chronic apical periodontitis, the present findings using a large-scale analysis allowed the inclusion of some newly named species and as-yet-uncultivated phylotypes in the set of candidate pathogens associated with this disease.
doi:10.1128/JCM.00431-08
PMCID: PMC2576597  PMID: 18768651
25.  Detection of Enterococcus faecalis in Necrotic Teeth Root Canals by Culture and Polymerase Chain Reaction Methods 
European journal of dentistry  2007;1(4):216-221.
Objectives
The aim of this study was to investigate the presence of Enterococcus faecalis in endodontic infections in both deciduous and permanent teeth by culture and polymerase chain reaction (PCR) methods.
Methods
A total of 145 children aged 5–13 years old were involved in this study. The presence of E. faecalis in necrotic deciduous and permanent teeth root canals was studied using culture and polymerase chain reaction methods.
Results
Among 145 molar teeth, 57% (n=83) presented necrotic asymptomatic pulp tissues and were included in this study. Culture and PCR methods detected the test species in 18 and 22 of 83 teeth involved, respectively. E. faecalis was cultured from 8 (18%) of 45 necrotic deciduous teeth and from 10 (26%) of 38 necrotic permanent teeth. PCR detection identified the target species in 10 (22%) and 12 (32%) of necrotic deciduous and permanent teeth respectively. Statistically significant difference in the presence of E. faecalis in deciduous and permanent teeth was found by culture and PCR methods (P=0.03 and 0.02, respectively). The difference in the presence of E. faecalis between two different methods was not statistically significant (P>.05).
Conclusions
The results of the present study confirm that both culture and PCR methods are sensitive to detect E. faecalis in root canals.
PMCID: PMC2609913  PMID: 19212470
Enterococcus faecalis; Necrotic tooth; Culture; Polymerase chain reaction

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