Bacteria recovered from teeth with apical periodontitis after antimicrobial endodontic treatment

Chávez de Paz LE, Dahlén G, Molander A, Möller Å, Bergenholtz G . Bacteria recovered from teeth with apical periodontitis after antimicrobial endodontic treatment. International Endodontic Journal, 36 , 500–508, 2003. Aim To determine whether there is a pattern for certain bacteria to remain after chemo‐mechanical treatment of root canals in teeth with apical periodontitis. Methodology Consecutive root‐canal samples of 200 teeth receiving root‐canal treatment, referred from general practitioners and endodontic specialists for analyses of cultivable microbes, were studied prospectively. To be included, samples had to be taken at a treatment session subsequent to the one at which endodontic therapy was initiated. All samples were from teeth that either presented with clinical or radiographic evidence of apical periodontitis or both. Bacteriological findings were linked to clinical and radiographic parameters including status of the root canal prior to treatment, namely, vital pulp, necrotic pulp or root filled. Results A total of 248 strains were isolated from 107 teeth giving bacterial growth. Gram‐positives predominated (85%). Lactobacillus spp. (22%), nonmutans streptococci (18%), and Enterococcus spp. (12%) were the most common isolates. Gram‐negative anaerobes were relatively sporadic. Large radiographic bone lesions, persistent pain and use of intracanal calcium hydroxide dressing correlated with bacterial presence (P < 0.05). Conclusions Once established, nonmutans streptococci, enterococci and lactobacilli appear to survive commonly following root‐canal treatment of teeth with clinical and radiographical signs of apical periodontitis.     

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目的探讨根管再治疗的技术及方法。方法选取2005年7月至2006年8月于东南大学医学院附属徐州中心医院口腔科就诊的38例患者共46颗需根管再治疗的患牙,采用小号K型锉配合次氯酸钠溶液和乙二胺四乙酸二钠(EDTA)溶液探查根管并清理根管内感染物质,封入氢氧化钙糊剂1～2周,采用手用镍钛器械ProTaper进行根管预备,侧向加压技术充填根管,记录治疗过程中患牙症状的改善程度、根管疏通情况、根管预备和充填效果。结果45颗患牙根管疏通成功,治疗过程中症状明显缓解或完全消失,瘘管明显减小或消失,根管预备时无根管偏移、根尖阻塞、台阶等并发症发生,根管形态良好。结论根管再治疗时应强调彻底清除根管内感染物质。采用次氯酸钠和EDTA溶液清理根管,氢氧化钙消毒根管,器械ProTaper进行根管预备能取得良好的治疗效果。     

Effect of root canal procedures on endotoxins and endodontic pathogens

BACKGROUND/AIMS: The purpose of this study was to determine the amount of endotoxin (lipopolysaccharide) and cultivable bacteria in human necrotic root canals before (S1) and after chemo-mechanical preparation using chlorhexidine (CHX) gel as auxiliary chemical substance (S2), and after 7 days of intracanal dressing (S3) in order to evaluate the anti-endotoxin and antimicrobial effects of endodontic procedures. METHOD: Twenty-four teeth were selected for the present study. Chemo-mechanical preparation was performed using 2% CHX gel and three different intracanal medicaments [CaOH2 paste; 2% CHX gel; and CaOH2 + 2% CHX gel]. A quantitative chromogenic Limulus amoebocyte lysate assay was used to measure the amount of endotoxin. Aerobic and anaerobic techniques were used to isolate and identify bacteria, and to determine the bacterial reduction by counting colony-forming units (CFU). RESULTS: Endotoxins and bacteria were present in 100% of the initial samples, with endotoxin concentration ranging from 62.93 to 214.56 UE/ml and CFU ranging from 4 x 10(5) to 2.6 x 10(6). After chemo-mechanical preparation a mean endotoxin reduction of 44.4% was found. Eight (33.3%) root canals were still positive by culture analysis with a mean reduction of bacteria (CFU) of 99.96%. After 7 days of intracanal dressing, endotoxin concentration decreased by only 1.4% compared with S2, and residual bacteria were recovered by culture analysis in 13 cases (54.1%). No significant difference was found among different intracanal medicaments. CONCLUSION: Relatively high values of endotoxin were still present in the root canal after chemo-mechanical preparation although the majority of bacteria were eliminated. No improvement was achieved by 7 days of intracanal dressing.     

Molecular identification and quantification of bacteria from endodontic infections using real‐time polymerase chain reaction

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 × 10⁶ and was significantly reduced following root canal preparation (3.6 × 10⁴) and intracanal dressing (1.4 × 10⁵). Corresponding values for primary infections were: 4.6 × 10⁷, 3.6 × 10⁴, and 6.9 × 10⁴. 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%.     

根管治疗失败病例根管内微生物检测及药敏试验

目的通过对根管治疗失败病例根管内微生物进行培养检测，了解失败病例根管内菌群特征，同时对检测出的细菌进行药敏试验，为临床根管治疗提供参考。方法选择86例根管治疗失败病例共86颗惠牙，去除根管内充填物后，对根管内细菌取样，进行培养和鉴定，用琼脂稀释法对根管内分离的优势菌进行药敏试验。结果根管治疗失败病例根管中微生物菌群组成以兼性厌氧菌为优势菌，主要以1-2种革兰阳性菌为主，肠球菌是最常检出的细菌。失败病例根管内检出的兼性及专性厌氧菌对青霉素G、甲醛甲酚、甲硝唑敏感。结论细菌与根管治疗失败密切相关，根管治疗失败病例根管内微生物组成有其独特性。临床应选择敏感性药物进行治疗。     

Microbiologic endodontic status of young traumatized tooth

Traumatic dental injuries could expose the dentin and, even the pulp, to the oral environment, making possible their contamination. The presence of microorganisms causes pulpal disease and further a tecidual clutter in the periradicular region. The therapy of periradicular pathosis is the consequence of a correct diagnoses which depends on the knowledge of the nature and complexity of endodontic infections. As there is no information on the microbiology of primary endodontic infection in young teeth, the aim of the current study was to investigate the microbiologic status of root canals from permanent young teeth with primary endodontic infection. Twelve patients with the need for endodontic treatment participated in the study. The selected teeth were uniradicular and had an incomplete root formation. They had untreated necrotic pulp. After the access preparation, nineteen microbiologic samples were obtained from the root canals with sterile paper points. Afterwards, the paper points were pooled in a sterile tube containing 2 ml of prereduced transport fluid. The samples were diluted and spread onto plates with selective medium for Enterococcus spp. and for yeast species and onto plates with non-selective medium. A quantitative analysis was performed. The mean number of cultivable bacterial cells in the root canals was 5.7 × 10(6). In four samples (21.05%) black pigmented species were recovered and the mean number of cells was 6.5 × 10(5). One specimen (5.25%) showed the growth of Enterococcus species and the mean number of cells in this case was of 1.5 × 10(4) . The results showed a root canal microbiota with similar design as seen in completely formed teeth.     

Molecular identification and quantification of bacteria from endodontic infections using real-time polymerase chain reaction

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 × 10⁶ and was significantly reduced following root canal preparation (3.6 × 10⁴) and intracanal dressing (1.4 × 10⁵). Corresponding values for primary infections were: 4.6 × 10⁷, 3.6 × 10⁴, and 6.9 × 10⁴. 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%.     

The antibacterial effect of camphorated paramonochlorophenol, camphorated phenol and calcium hydroxide in the treatment of infected root canals

Abstract The bactericidal efficacy of calcium hydroxide, camphorated phenol and camphorated paramonochlorophenol as intracanal dressings was evaluated clinically when the root canals of 65 single-rooted teeth with periapical lesions were treated. A bacteriological technique that could detect even small numbers of anaerobic bacteria in the canals was used. After treatment, including intracanal dressing with calcium hydroxide paste (Calasept), bacteria were recovered from one of 35 treated root canals. After use of camphorated phenol or camphorated paramonochlorophenol as the dressing, bacteria were recovered from 10 of 30 treated root canals. The isolated bacteria were predominantly Gram-positive and anaerobic. There was no indication that specific bacteria were resistant to the treatment. The results indicate that the endodontic treatment of infected root canals can be completed in two appointments when calcium hydroxide paste is used as an intracanal dressing.     

Nonsurgical endodontic treatments in molar teeth with large periapical lesions in children: 2-year follow-up

Profound caries lesions may lead to invasion of microorganisms to the dental pulp, and periapical areas can promote the development of dentoalveolar abscess and periapical bone loss. Treatment options to manage large periapical lesions range from nonsurgical root canal treatment and/or apical surgical procedure to extraction. Young molar teeth with pulp necrosis and large periapical lesions in children are frequently treated with root canal treatment because the therapy is more difficult in multirooted teeth. In these case reports, nonsurgical endodontic treatments performed on 6 molar teeth with large periapical lesions, by repeated intracanal dressing with calcium hydroxide, are presented. Radiographs displayed significant bony healing at the end of the second year. In conclusion, large periapical lesions can respond favorably to nonsurgical treatment, and complex and difficult endodontic treatments in children might not be required.     

Fungi in endodontic infections

Fungi are chemoorganotroph eukaryotic microorganisms that can take part in endodontic infections and thereby may participate in the etiology of periradicular diseases. They possess virulence attributes--including adaptability to a variety of environmental conditions, adhesion to a variety of surfaces, the production of hydrolytic enzymes, morphologic transition, biofilm formation, and evasion and immunomodulation of the host defense--that may play a role in the pathogenesis of periradicular diseases. Fungi have occasionally been found in primary root canal infections, but they seem to occur more often in the root canals of obturated teeth in which treatment has failed. Candida albicans is by far the fungal species most commonly isolated from infected root canals, and this species has been considered a dentinophilic microorganism because of its invasive affinity to dentin. C albicans has also been discovered to be resistant to some intracanal medicaments, such as calcium hydroxide. Its ability to invade dentinal tubules and resistance to commonly used intracanal medicaments may help to explain why C albicans has been associated with cases of persistent root canal infections. Some medicaments, such as chlorhexidine digluconate, calcium hydroxide combinations (with camphorated paramonochlorophenol or chlorhexidine), and EDTA, have the potential to be used as effective intracanal medications for patients in whom fungal infection is suspected.     

A new bacterial species associated with failed endodontic treatment: identification and description of Actinomyces radicidentis

OBJECTIVE: This report describes 2 endodontic patients who had persistent signs and symptoms after conventional root canal treatment. The aim of this study was to determine what microorganisms were present in the root canals of the teeth with failed endodontic therapy. STUDY DESIGN: After removal of the root fillings, the canals were sampled by advanced microbiological techniques and the isolates were characterized by various tests. RESULTS: Bacteria, which grew in pure cultures, were isolated in each case. The bacteria were similar to each other and were classified as Actinomyces on the basis of phylogenic and phenotypic evidence. The bacteria were different from others within the genus, thus warranting designation as a new species, Actinomyces radicidentis. CONCLUSIONS: The 2 cases of endodontic failure were infected with A radicidentis, a new Actinomyces species. This bacterium joins a restricted group of other microorganisms that have been associated with failure of root canal treatment.     

干髓术失败患牙的根管再治疗

目的:通过对干髓术失败患牙进行根管再治疗,探讨此类病例的特点及再治疗方法.方法:选取干髓术失败的磨牙63个,采用小号K锉配合次氯酸钠溶液和EDTA溶液探查根管并清理根管内的感染物质,封入氢氧化钙糊剂1～2周,采用机动镍钛器械Hero642进行根管预备,侧向加压技术充填根管,记录治疗过程中患牙症状的改善程度,根管疏通情况,根管预备和充填的效果.结果:62个患牙的根管疏通成功,治疗过程中症状明显缓解或完全消失,瘘管明显减小或消失,根管预备时无根管偏移、根尖阻塞、台阶等并发症发生,根管形态良好.结论:干髓术失败患牙在根管治疗时强调彻底清除根管内的感染物质,采用次氯酸钠和EDTA溶液清理根管,氢氧化钙消毒根管,机用镍钛器械进行根管预备能取得良好的治疗效果.     

Clinical investigation of the effect of calcium hydroxide intracanal dressing on bacterial lipopolysaccharide reduction from infected root canals

The purpose of this clinical study was to determine the effect of 7 day intracanal dressing with calcium hydroxide on the amount of bacterial lipopolysaccharide (LPS; endotoxin) in human teeth with necrotic and infected pulp and apical periodontitis. Twenty‐five single‐rooted teeth with necrotic pulps and apical periodontitis were selected. Samples were collected before (S1), after root canal preparation (S2) and after 7 day intracanal dressing with calcium hydroxide (S3). The limulus amoebocyte lysate assay was used to quantify LPS. LPS was present in 100% of the root canals before (S1), after preparation (S2) and after 7 day intracanal dressing (S3). A significant reduction, equal to 29.54%, was found after root canal preparation (P < 0.05). A significant difference (equal to 25.26% reduction) was also detected between S2 and S3 (P < 0.05). Total endotoxin reduction (S3 compared with S1) was found to be 47.34%. Endotoxin concentration of the infected root canals was reduced after root canal preparation and also after 7 days of dressing of canals with calcium hydroxide; however, relatively high values of endotoxin remained in the root canals.     

根管治疗期间急性发作与慢性根尖周炎患牙根管细菌组成比较

目的:比较根管治疗期间炎症急性发作及慢性根尖周炎患牙根管内8种厌氧菌检出情况,分析急性发作时根管内定植细菌种类及其相关性。方法:分别提取26例根管预备后约诊期间炎症急性发作患牙根管样本和23例慢性根尖周炎患牙根管样本,提取样本细菌DNA,利用细菌16S rRNA引物通过PCR扩增方法鉴定细菌。结果:慢性根尖周炎样本根管细菌检出率达100%(23/23),根管治疗期间急性发作样本细菌检出率为92.31%(24/26);产黑普氏菌、齿垢密螺旋体和直肠弯曲杆菌在急性发作样本中的检出率较慢性根尖周炎样本显著增高(P<0.05)。急性发作样本中牙龈卟啉菌与福赛氏类杆菌的检出显著相关(OR>2,P<0.05)。结论:根管内感染是根管治疗期间炎症急性发作的重要原因,厌氧菌在急性发作的发生中起重要作用。     

The role of intracanal medication in root canal treatment

The role of intracanal medication as a root canal dressing is re-examined. In pulpectomy and some root canal treatments, where the root canal contains vital pulp tissue, it is doubtful whether a routine intracanal medicament is needed. In infected root canals, intracanal medication has been advocated for many purposes. An intracanal medicament is used to: (i) eliminate any remaining bacteria after canal instrumentation; (ii) reduce inflammation of periapical tissues and pulp remnants; (iii) render canal contents inert and neutralize tissue debris; (iv) act as a barrier against leakage from the temporary filling; (v) help to dry persistently wet canals. However, most of the indications for intracanal medicaments are questionable. Intracanal medicaments should only be used for root canal disinfection as part of controlled asepsis in infected root canals, and their role is secondary to cleaning and shaping of the root canal. Thorough canal debridement and adequate canal preparation are more pertinent, and their importance is emphasized. Bacteriological sampling may be necessary if a tooth does not respond to treatment, to help in the choice of intracanal medicament.     

Profiling of Propionibacterium acnes recovered from root canal and blood during and after endodontic treatment.

This report describes the first results of an ongoing study of bacteremia after endodontic treatment of teeth with Asymptomatic apical periodontitis. After access cavity preparation, microbiological samples were taken from the root canal under aseptic conditions in 4 single-rooted teeth in 4 patients. In treatment of 2 of the patients, the first 3 reamers (sizes 15-25) were deliberately used to a level 2 mm beyond the apical foramen. In 2 patients the instrumentation ended inside the root canal 1 mm short of the apical foramen. Blood samples were taken from the patients during the endodontic instrumentation and 10 min after the treatment was completed. Using lysis-filtration under anaerobic conditions, the blood was passed through a cellulose membrane filter. The filters as well as the root canal samples were incubated using an anaerobic technique. Anaerobic bacteria were isolated from all root canals. In the 2 patients where overinstrumentation had occurred, Propionibacterium acnes was recovered both from the root canals and from the blood samples taken during and after the treatment had been completed. Biochemical profiles, antibiotic susceptibility tests and electrophoresis of soluble proteins revealed that Propionibacterium acnes isolated from the root canal and blood samples were identical within patients, but varied between patients. Facultative anaerobic bacteria including Streptococcus sanguis were recovered from only one root canal sample and not from the blood samples.     

ASSOCIATION OF CALCIUM HYDROXIDE AND METRONIDAZOLE IN THE TREATMENT OF DOG'S TEETH WITH CHRONIC PERIAPICAL LESION

One of the primary objectives of endodontic treatment of teeth with pulp necrosis is the elimination of microorganisms from the root canal system, as effectively as possible, especially in cases with chronic periapical lesions. AIM: The purpose of this study was to analyze the response of the periapical tissue of dogs'' teeth with chronic periapical lesions to endodontic treatment performed with utilization of metronidazole, calcium hydroxide, and an association of both as root canal dressings. METHODOLOGY: Forty root canals were submitted to pulpectomy and the root canals were kept exposed to the oral environment for 6 months. Then, they were submitted to biomechanical preparation and divided into 4 study groups with 10 specimens: group I – no root canal dressing; group II – calcium hydroxide; group III – metronidazole; group IV – calcium hydroxide associated to metronidazole. After 15 days, the root canals were filled with Fill Canal sealer. After 90 days, the animals were killed and the especimens processed for histological analysis. RESULTS: Calcium hydroxide dressing provided a significantly better outcome compared to other experimental groups (α = 0.01). Also, the results of the association of metronidazole and calcium hydroxide were similar to those observed for the metronidazole group. The worst results were obtained by the no root canal dressing group. CONCLUSION: The use of metronidazole alone or associated with Calcium hydroxide, did not improve periapical healing when compared to Calcium hydroxide dressing.     

Profiling of Propionibacterium acnes recovered from root canal and blood during and after endodontic treatment

Abstract This report describes the first results of an ongoing study of bacteremia after endodontic treatment of teeth with Asymptomatic apical periodontitis. After access cavity preparation, microbiological samples were taken from the root canal under aseptic conditions in 4 single-rooted teeth in 4 patients. In treatment of 2 of the patients, the first 3 reamers (sizes 15-25) were deliberately used to a level 2 mm beyond the apical foramen. In 2 patients the instrumentation ended inside the root canal 1 mm short of the apical foramen. Blood samples were taken from the patients during the endodontic instrumentation and 10 min after the treatment was completed. Using lysis-filtration under anaerobic conditions, the blood was passed through a cellulose membrane filter. The filters as well as the root canal samples were incubated using an anaerobic technique. Anaerobic bacteria were isolated from all root canals. In the 2 patients where overinstrumentation had occurred, Propionibacterium acnes was recovered both from the root canals and from the blood samples taken during and after the treatment had been completed. Biochemical profiles, antibiotic susceptibility tests and electro-phoresis of soluble proteins revealed that Propionibacterium acnes isolated from the root canal and blood samples were identical within patients, but varied between patients. Facultative anaerobic bacteria including Streptococcus sanguis were recovered from only one root canal sample and not from the blood samples.     

Electrophoresis of whole-cell soluble proteins of microorganisms isolated from bacteremias in endodontic therapy

We have previously demonstrated that anaerobic bacteria are the microorganisms most frequently isolated from blood following endodontic therapy of teeth with apical periodontitis. Phenotypic characterisation of the isolates suggested that the bacteria in the blood originated from the root canal. The present experiment using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was carried out in an effort to verify these findings, and to further study the microorganisms involved in endodontic bacteremias. Soluble cellular proteins were extracted from 11 reference strains and 26 bacterial isolates recovered from the root canal and blood. These included Propionibacterium acnes, Peptostreptococcus prevotii, Fusobacterium nucleatum, Prevotella intermedia, Actinomyces israelii, Streptococcus intermedius, Streptococcus sanguis. The electrophoretic patterns mostly confirmed the identity of the isolates as determined by the biochemical and antimicrobial resistance tests. Furthermore, with this typing method the species Prevotella intermedia and Prevotella nigrescens could be differentiated. These species had been recovered from both root canal and blood. Also, differences between subspecies of Fusobacterium nucleatum became evident with SDS-PAGE, and the results indicated that the organism recovered from the root canal and blood was Fusobacterium nucleatum subsp. vincentii. The electrophoretic patterns of the different organisms isolated from the root canal and the blood were similar, providing further evidence that the bacteria found in the blood originated from the root canal.     

Microbiological evaluation of clindamycin as a root canal dressing in teeth with apical periodontitis

The present investigation was designed to study the effect of clindamycin on root canal infection when placed as an intracanal dressing. Twenty-five teeth with necrotic pulps and periapical radiolucencies were included. Following initial bacteriological sampling and routine instrumentation, clindamycin powder mixed to a paste with saline was applied for 14 days. The presence or absence of bacteria was determined in samples taken immediately after removal of the dressing, and after a period of 7 days during which the canals were filled with sampling fluid. Bacteria were recovered from four and six teeth respectively. The results indicated that clindamycin offered no advantage over conventional root canal dressings, such as calcium hydroxide, and it is therefore not recommended for use in routine endodontic therapy.