Identification of Enterococcus faecalis in root-filled teeth with or without periradicular lesions by culture-dependent and-independent approaches

Enterococcus faecalis is the most commonly found species in root-filled teeth evincing recalcitrant periradicular lesions and as a consequence, a role in causation of endodontic treatment failure has been suggested. The purpose of this study was to evaluate the prevalence of this bacterial species in root-filled teeth with or without periradicular lesions. Identification of E. faecalis was carried out by polymerase chain reaction (PCR) or conventional culture procedures. Overall, E. faecalis was detected by species-specific 16S rRNA gene-based PCR in 40/50 teeth (80%), while culture revealed the occurrence of this species in 8/50 teeth (16%). PCR was significantly more effective than culture in detecting this bacterial species (p < 0.001). Of 27 root-filled teeth with no periradicular lesions, E. faecalis was found in 22 cases (81.5%) by PCR and in five cases (18.5%) by culture. Of 23 root-filled teeth with periradicular lesions, E. faecalis was identified in 18 cases (78%) by PCR and in three cases (13%) by culture. Regardless of the identification technique used, no significant difference was observed when comparing the occurrence of E. faecalis in root-filled teeth with and without periradicular lesions (p > 0.05). Although these findings apparently put into question the status of E. faecalis as the main species causing endodontic treatment failure, other related factors still need to be clarified before this assumption turns into certainty.     

Association of Enterococcus faecalis with different forms of periradicular diseases

Data from culture studies have revealed that Enterococcus faecalis is occasionally isolated from primary endodontic infections but frequently recovered from treatment failures. This molecular study was undertaken to investigate the prevalence of E. faecalis in endodontic infections and to determine whether this species is associated with particular forms of periradicular diseases. Samples were taken from cases of untreated teeth with asymptomatic chronic periradicular lesions, acute apical periodontitis, or acute periradicular abscesses, and from root-filled teeth associated with asymptomatic chronic periradicular lesions. DNA was extracted from the samples, and a 16S rDNA-based nested polymerase chain reaction assay was used to identify E. faecalis. This species occurred in seven of 21 root canals associated with asymptomatic chronic periradicular lesions, in one of 10 root canals associated with acute apical periodontitis, and in one of 19 pus samples aspirated from acute periradicular abscesses. Statistical analysis showed that E. faecalis was significantly more associated with asymptomatic cases than with symptomatic ones. E. faecalis was detected in 20 of 30 cases of persistent endodontic infections associated with root-filled teeth. When comparing the frequencies of this species in 30 cases of persistent infections with 50 cases of primary infections, statistical analysis demonstrated that E. faecalis was strongly associated with persistent infections. The average odds of detecting E. faecalis in cases of persistent infections associated with treatment failure were 9.1. The results of this study indicated that E. faecalis is significantly more associated with asymptomatic cases of primary endodontic infections than with symptomatic ones. Furthermore, E. faecalis was much more likely to be found in cases of failed endodontic therapy than in primary infections.     

Microbial analysis of canals of root-filled teeth with periapical lesions using polymerase chain reaction

The objective of the present study was to investigate the presence of nine bacterial species in root-filled teeth associated with periapical lesions using a polymerase chain reaction analysis and to correlate these species with clinical features of the cases. DNA was extracted from 45 canal samples of root-filled teeth with periapical lesions. A PCR assay using species-specific primers of 16S rDNA and the downstream intergenic spacer region was used for microbial detection. Enterococcus faecalis was the most prevalent species, detected in 77.8% of the study teeth, followed by Peptostreptococcus micros, detected in 51.1%. Porphyromonas gingivalis, Porphyromonas endodontalis, Prevotella intermedia, and Prevotella nigrescens were detected in 35.6%, 22.2%, 11.1%, and 11.1% of the sampled teeth, respectively. Moreover, PCR detected Filifactor alocis in 26.7%, Treponema denticola in 24.4%, and Tannerella forsythia in 4.4% of the samples. T. denticola and P. micros were statistically associated with tenderness to percussion (p < 0.05). P. nigrescens was associated with the presence of spontaneous pain and abscess (p < 0.05). P. endodontalis and P. nigrescens were associated with purulent exudates (p < 0.05). Synergistic relationship was also observed between some species. The results of this study indicated that E. faecalis was the most frequently identified test species by PCR in teeth with failing endodontic treatment.     

Detection and eradication of microorganisms in root-filled teeth associated with periradicular lesions: an in vivo study

This study determined the presence of microorganisms by culture and polymerase chain reaction in asymptomatic root-filled teeth with periradicular lesions. Furthermore, a disinfecting regimen using sodium hypochlorite (NaOCl), ethylenediaminetetraacetic acid (EDTA), chlorhexidine digluconate (CHX) irrigation, and calcium hydroxide (Ca(OH)(2)) dressing was assessed. After removal of the root-filling material, specimens of 20 cases undergoing retreatment were sampled. Moreover, the canals were sampled after each step of the disinfecting regimen. Prevalence of microorganisms was 60% by culture and 65% by polymerase chain reaction. In four of those samples (31%), DNA of Enterococcus faecalis was found. After further root canal preparation and irrigation using NaOCl and EDTA, microorganisms could be detected in none of the teeth. Thus, CHX and Ca(OH)(2) could not show further disinfection. In contrast, microorganisms were found in two teeth after the interappointment dressing. It may be concluded that proper root canal preparation and irrigation using NaOCl and EDTA are sufficient for decontamination of the root canal system during endodontic retreatment.     

Detection of Filifactor alocis in endodontic infections associated with different forms of periradicular diseases

Recent molecular studies have expanded the list of suspected endodontic pathogens. The aim of this study was to evaluate the occurrence of Filifactor alocis in primary endodontic infections associated with different forms of periradicular diseases. Identification by nested polymerase chain reaction was performed in root canal samples from teeth associated with either asymptomatic periradicular lesions or acute apical periodontitis. Samples were also taken by aspiration of purulent exudate associated with acute apical abscesses. DNA extracted from the samples was initially amplified using universal 16S rDNA primers followed by a second round of amplification using the first PCR products to detect a specific fragment of F. alocis 16S rDNA. F. alocis was detected in 12/21 (57.1%) root canal samples from teeth showing asymptomatic periradicular lesions and in 3/10 (30%) samples taken from root canals associated with acute apical periodontitis. This species occurred in 8/19 (42.1%) pus aspirates obtained from abscessed teeth. In general, F. alocis was detected in 23/50 (46%) samples taken from endodontic infections. These findings suggest that F. alocis is involved in the etiology of different forms of periradicular diseases and has the potential to be an endodontic pathogen.     

Bacteroides forsythus in primary endodontic infections as detected by nested PCR

The purpose of this study was to investigate the prevalence of Bacteroides forsythus in primary endodontic infections using a species-specific nested polymerase chain reaction assay. Samples were collected from 50 teeth having carious lesions, necrotic pulps, and different forms of periradicular diseases. DNA extracted from the samples was initially amplified using universal 16S rDNA primers. A second round of amplification used the first polymerase chain reaction products to detect a specific fragment of B. forsythus 16S rDNA. B. forsythus was detected in 13 of 22 asymptomatic cases (59.1%), 4 of 10 root canals associated with acute apical periodontitis (40%), and 9 of 18 cases diagnosed as acute periradicular abscesses (50%). There was no relationship between the presence of B. forsythus and the occurrence of symptoms. In general, this bacterial species was detected in 26 of 50 samples of endodontic infections (52%). The findings of this study support the assertion that this bacterial species is associated with infections of endodontic origin and suggest that B. forsythus may be involved in the pathogenesis of different forms of periradicular lesions.     

Pseudoramibacter alactolyticus in primary endodontic infections

A nested polymerase chain reaction (PCR)-based method was used to directly survey samples taken from primary endodontic infections for the occurrence of Pseudoramibacter alactolyticus. Identification by nested PCR was performed in root-canal samples from teeth associated with asymptomatic periradicular lesions or acute apical periodontitis, and in pus samples from acute periradicular abscesses. DNA was extracted from the samples and initially amplified using universal 16S rDNA primers. A second round of amplification used the first PCR products to detect a specific fragment of P. alactolyticus 16S rDNA. P. alactolyticus was detected in 76% of root-canal samples from teeth showing asymptomatic periradicular lesions, in 60% of samples taken from root canals associated with acute apical periodontitis, and in 32% of pus samples aspirated from acute periradicular abscesses. No significant association of this species with clinical symptoms was observed (p > 0.01). In general, P. alactolyticus occurred in 56% of samples taken from infections of endodontic origin. The high prevalence of P. alactolyticus in infections of endodontic origin as detected by nested PCR in this study, and its apparent pathogenicity, particularly in mixed infections, indicate that this bacterial species is a candidate endodontic pathogen that can participate in the etiology of different forms of periradicular diseases.     

Enterococcus spp. in endodontically treated teeth with and without periradicular lesions

The purpose of this study was to determine if Enterococcus spp. are more prevalent in endodontically treated teeth with periradicular lesions compared with teeth that require retreatment but have no periradicular rarefaction. Fifty-eight teeth that had received root canal therapy more than 1 yr previously and required retreatment were included. Designation of lesion versus no lesion was determined by two experienced endodontists. DNA extraction and PCR amplification were performed using ubiquitous 16S rDNA bacterial primers, as well as Enterococcus spp.-specific primers. The results showed that the overall prevalence of bacteria was 90% and Enterococcus spp. was 12%. chi analysis revealed a statistically significant relationship between the presence of a lesion and the presence of bacteria, as detected by the universal primers (p = 0.032). Using logistic regression, a statistically significant relationship was found between teeth with normal periapex and the presence of Enterococcus spp. (p = 0.023). This study revealed that bacteria are significantly associated with endodontic treatment failure but enterococci are not associated with disease.     

Treponema socranskii in primary endodontic infections as detected by nested PCR

Spirochetes have been frequently observed in root canal infections, but they were rarely identified. The purpose of this study was to investigate the prevalence of Treponema socranskii in primary endodontic infections using a species-specific nested polymerase chain reaction assay. Samples were collected from 60 teeth having carious lesions, necrotic pulps, and different forms of periradicular diseases. DNA extracted from the samples was initially amplified using universal 16S rDNA primers. A second round of amplification used the first polymerase chain reaction products to detect a specific fragment of T. socranskii 16S rDNA. T. socranskii was detected in 11 of 28 asymptomatic cases (39.3%), five of 12 root canals associated with acute apical periodontitis (41.7%), and five of 20 cases diagnosed as acute periradicular abscesses (25%). There was no relationship between the presence of T. socranskii and the occurrence of symptoms. In general, this spirochete was detected in 21 of 60 samples of endodontic infections (35%). Findings suggest that T. socranskii can be involved in the pathogenesis of different forms of periradicular lesions.     

Nested PCR detection of Centipeda periodontii in primary endodontic infections

In recent years, molecular genetic methodologies have provided significant additional knowledge about components of the microbiota associated with infections of endodontic origin. Following this research line, the purpose of the present study was to investigate the prevalence of Centipeda periodontii in primary endodontic infections using a species-specific nested PCR assay. Samples were collected from fifty teeth having carious lesions, necrotic pulps, and different forms of periradicular diseases. DNA extracted from the samples was initially amplified using universal 16S rDNA primers, and a second round of amplification used the first PCR products to detect a specific fragment of C. periodontii 16S rDNA. This species was detected in 3 (13%) of 23 asymptomatic cases, in 1 (14%) of 7 cases diagnosed as acute apical periodontitis, and in 3 (15%) of 20 pus samples aspirated from acute periradicular abscesses. There was no significant association between C. periodontii and the presence of clinical symptoms. Overall, C. periodontii was detected in 14% of the cases of endodontic infections. This is probably the hitherto first study to detect C. periodontii in primary endodontic infections. The specific role played by this bacterial species in infections of endodontic origin awaits further clarification.     

Phenotypic and genotypic identification of enterococci isolated from canals of root-filled teeth with periapical lesions

The objectives of the present study were to identify enterococcal species isolated from the canals of root-filled teeth with periapical lesions using biochemical and molecular techniques, and to investigate the genetic diversity of the isolates. Twenty-two Enterococcus strains, isolated from the canals of root-filled teeth with persisting periapical lesions, were identified to species level using rapid ID 32 STREP galleries and partial 16S rDNA sequencing. To subtype the strains, genomic DNA from the isolates was analyzed by pulsed field gel electrophoresis (PFGE) after digestion with SmaI. Intragenic regions of two genes, ace and salA, were sequenced for further differentiation of the isolates. All strains were identified as Enterococcus faecalis by both commercial kit and partial 16S rDNA sequencing. PFGE with SmaI of 22 isolates demonstrated 18 macrorestriction profiles, whereas 13 distinct genotypes were identified after analysis of the ace and salA composite sequences. Most of the isolates from distinct patients had different PFGE profiles. Moreover, in two cases, different E. faecalis strains were found in different root-filled teeth from the same mouth. E. faecalis was the only enterococcal species isolated from the canals of root-filled teeth with periapical lesions. Genetic heterogeneity was observed among the E. faecalis isolates following PFGE and sequence-based typing method. Furthermore, the genetic diversity within root canal strains was similar to previous reports regarding E. faecalis isolates from different clinical and geographic origins.     

Evaluation of root canal microorganisms isolated from teeth with endodontic failure and their antimicrobial susceptibility

Studies of the microbiota from the canals of teeth with failure of endodontic therapy have revealed that it differs markedly from that of untreated necrotic dental pulps. This study aimed to evaluate the microbiota of 30 root-filled teeth with persisting periapical lesions and to test the antibiotic susceptibility of the most prevalent species. Microbial samples, isolation and speciation were done using advanced microbiologic techniques for anaerobic species. A total of 55 bacterial species were isolated, 80% were gram-positives and 58% facultative anaerobic microorganisms. The bacterial genera most frequently recovered were Enterococcus, Streptococcus, Peptostreptococcus and Actinomyces. Antibiotic sensitivity of Enterococcus faecalis and Peptostreptococcus spp. was accomplished with the E-test system. All species studied were susceptible to benzylpenicillin, amoxicillin, amoxicillin combined with clavulanate. However, 20% of the E.faecalis strains were resistant to erythromycin and 60% to azithromycin. It was concluded that microbial flora in canals after endodontic failure comprised predominantly facultative anaerobes and gram-positive species. E.faecalis was the species most frequently isolated and showed erythromycin and azithromycin resistance among the isolates.     

Microorganisms from canals of root-filled teeth with periapical lesions

AIM: The objective of the present study was to identify the microbial flora within root canals of teeth with failed root-canal treatment and to determine the association of the various species with clinical features. METHODOLOGY: Sixty root-filled teeth with persisting periapical lesions were selected for this study. During nonsurgical endodontic re-treatment, the root-filling material was removed and the canals were sampled. Microbial sampling, isolation and species determination were performed using advanced microbiological techniques for anaerobic species. The association of microbiological findings with clinical features was investigated. RESULTS: Microorganisms were recovered from 51 teeth. In most cases, one or two strains per canal were found. Of the microbial species isolated, 57.4% were facultative anaerobic species and 83.3% Gram-positive microorganisms. Enterococcus faecalis was the most frequently recovered bacterial species. Obligate anaerobes accounted for 42.6% of the species and the most frequently isolated genera was Peptostreptococcus. which was associated with clinical symptoms (P < 0.01). Significant associations were also observed between: (a) pain or history of pain and polymicrobial infections or anaerobes (P < 0.05): (b) tenderness to percussion and Prevotella intermedia/P. nigrescens (P < 0.05); (c) sinus and Streptococcus spp. (P < 0.001) or Actinomyces spp. (P < 0.01); (d) coronally unsealed teeth and Streptococcus spp. or Candida spp. (both with P < 0.01). CONCLUSION: The microbial flora in canals after failure of root-canal treatment were limited to a small number of predominantly Gram-positive microbial species. Facultative anaerobes, especially E. faecalis, were the most commonly isolated microorganisms, however, polymicrobial infections and obligate anaerobes were frequently found in canals of symptomatic root-filled teeth.     

显微根尖手术治疗39例慢性根尖周炎病例的临床疗效

目的评价显微根尖手术治疗39例慢性根尖周炎病例的临床疗效。方法对39例慢性根尖周炎病例进行显微根尖手术治疗．包括在牙科手术显微镜下借助显微外科器械对患牙进行根尖刮治、根尖切除、根尖倒预备和MTA倒充填。术后每3个月复诊．通过临床和X线片检查评价术后1年的疗效，分为愈合、好转和无效病例。结果39例慢性根尖周炎病例1年后随访的治疗成功率为94．9％，其中治愈病例为82．1％．好转病例为12．8％。结论显微根尖手术对治疗慢性根尖周炎病损具有良好疗效。     

Frequency and technical standard of endodontic treatment in a Swedish population

Abstract The purpose of this investigation was to study the frequency and technical standard of endodontic treatment in a Swedish population. The material consisted of full-mouth radio-graphic surveys from 200 patients treated by general practice dentists, and the radiographs were analyzed by two observers. Thirteen percent of the teeth had been endodontically treated. Periradicular radiolucencies were found in 5.2% of the teeth and 26.4% of the endodontically treated teeth had such periradicular radiolucencies. In nearly half of the root-filled teeth, the root filling ended more than 2 mm from the apex, and only 56.3% were judged to have a proper seal. It is concluded that the need for endodontic treatment is great and the technical standard of the root fillings is poor. This strongly indicates that there is a need for standardized endodontic treatment methods and for more specialists in endodontics in Sweden.     

The odontogenic keratocyst: A potential endodontic misdiagnosis

Odontogenic keratocysts manifest themselves as radiolucencies that can appear anywhere in the maxilla or mandible, including periradicular areas; they may thus masquerade as lesions of endodontic origin. This retrospective study examined 239 odontogenic keratocysts received by the Oral Pathology Laboratory at Temple University School of Medicine over a 3-year period. Twenty-one (9%) of the cysts received were located periradicularly; of these 21, 12 (57%) were associated with nonvital or endodontically treated teeth and thus mimicked lesions of endodontic origin. Because of its aggressive nature and tendency to recur, the periradicular odontogenic keratocyst should be included in the differential diagnosis of lesions that are refractory to endodontic treatment.     

Periradicular radiographic assessment in diabetic and control individuals

OBJECTIVE: The purpose of this study was to investigate the prevalence of radiographic periradicular radiolucencies in endodontically treated and untreated teeth in patients with and without diabetes. STUDY DESIGN: The records of 30 subjects with diabetes and 23 control subjects attending the Endodontic Graduate Clinic at the University of Florida, Gainesville, were reviewed. The number of teeth with root canal treatments with and without periradicular radiolucencies and the number of teeth without endodontic treatment but with periradicular lesions were recorded. RESULTS: There were no main effects of sex, diabetes diagnosis, or age (the covariate) on the 3 outcomes of interest- nonsurgical endodontic treatment (NSE) with lesions, NSE without lesions, and no NSE with lesions. However, there were significant interactions between sex and diabetes diagnosis for both of the endodontic outcomes, NSE with lesions (F = 4.292; P <.05) and NSE without lesions (F = 4.241; P <.05). This meant that men with type 2 diabetes who had endodontic treatments were more likely to have residual lesions after treatment. CONCLUSION: Type 2 diabetes is associated with an increased risk of ill response by the periradicular tissues to odontogenic pathogens.     

The effect of diabetes mellitus on endodontic treatment outcome: data from an electronic patient record

BACKGROUND: The authors used a custom-built electronic record system to investigate endodontic diagnostic and treatment outcome data in patients with and without diabetes. METHODS: The medical histories and endodontic treatment data for nonsurgical endodontic patients treated in predoctoral and postgraduate specialty clinics were entered into an electronic record system. A total of 5,494 cases (including 284 cases in patients with diabetes) were treated, and 540 cases (including 73 cases in patients with diabetes) had follow-up data two years or more postoperatively. The authors performed univariate and multivariate analyses to determine important factors affecting endodontic diagnosis and treatment outcome. RESULTS: Patients with diabetes had increased periodontal disease of teeth with endodontic involvment compared with patients who did not have diabetes. There was a trend toward increased symptomatic periradicular disease in patients with diabetes who received insulin, as well as flareups in all patients with diabetes. Two years or longer postoperatively, 68 percent of cases followed were successful. Older age, the absence of preoperative lesions, the presence of permanent restorations and longer postoperative evaluation periods all were associated with a successful outcome. A multivariate analysis showed that in cases with preoperative periradicular lesions, a history of diabetes was associated with a significantly reduced successful outcome. CONCLUSIONS: Patients with diabetes have increased periodontal disease in teeth involved endodontically and have a reduced likelihood of success of endodontic treatment in cases with preoperative periradicular lesions. CLINICAL IMPLICATIONS: Patients with diabetes who are treated endodontically should be assessed carefully and be treated with effective antimicrobial root canal regimens, particularly in cases with preoperative lesions.     

Detection of Porphyromonas endodontalis in infected root canals by 16S rRNA gene-directed polymerase chain reaction

Porphyromonas endodontalis has been isolated from the endodontic infections mainly in symptomatic teeth. This study evaluated the occurrence of P. endodontalis in both symptomatic and asymptomatic endodontic infections using 16S rRNA gene-directed polymerase chain reaction. P. endodontalis was detected in 39.5% of the cases (17 of 43 teeth). It was present in 4 of the 6 cases with acute periradicular abscess (66.7%) and in 13 of the 37 other cases (35.1%). The presence of P. endodontalis was associated with an asymptomatic periradicular lesion in 6 cases (25%) and in 10 teeth with tenderness to percussion (52.6%). P. endodontalis was also found in one asymptomatic case without evidence of periradicular pathosis. Our results indicated that, although P. endodontalis is commonly detected in symptomatic cases, it can be present in asymptomatic root canal infections. Further studies should determine if this bacterial species is really an important endodontopathogen.     

Application of denaturing gradient gel electrophoresis (DGGE) to the analysis of endodontic infections

The recent expanding use of cultivation-independent techniques for bacterial identification is reliant on the lack of knowledge of the conditions under which most bacteria are growing in their natural habitat and the difficulty to develop culture media that accurately reproduce these conditions. A molecular method that has been recently used in several areas to examine the bacterial diversity living in diverse environments is the denaturing gradient gel electrophoresis (DGGE). In DGGE, polymerase chain reaction (PCR)-generated DNA fragments of the same length but with different base-pair sequences can be separated. Separation is based on electrophorectic mobility of a partially melted double-strand DNA molecule in polyacrylamide gels, which is decreased when compared with that of the completely helical form of the molecule. Molecules with different sequences may have a different melting behavior and will therefore stop migrating at different positions in the gel. Application of the PCR-DGGE method in endodontic research has revealed that there are significant differences in the predominant bacterial composition between asymptomatic and symptomatic cases. This suggests that the structure of the bacterial community can play a role in the development of symptoms. In addition, new bacterial phylotypes have been disclosed in primary endodontic infections. PCR-DGGE has also confirmed that intra-radicular infections are a common finding in root-filled teeth associated with persistent periradicular lesions. The microbiota in failed cases significantly vary from teeth to teeth, with a mean number of species far higher than previously shown by culturing approaches. Application of the PCR-DGGE technique in endodontic microbiology research has the potential to shed light on several aspects of the different types of endodontic infection as well as on the effects of treatment procedures with regard to infection control.