Persistent Periapical Lesions Research Articles

Enterococcus faecalis affects the proliferation and differentiation of ovine osteoblast-like cells

Enterococcus faecalis (E. faecalis) is a Gram-positive bacterium, mostly recovered from root-filled teeth with persistent periapical lesions. Bacterial contamination of root canals inevitably results in interaction between E. faecalis and periapical tissues during the dynamic process of periapical inflammation. This study investigated the impact of heat-inactivated endodontic E. faecalis on the proliferation and the differentiation of ovine osteoblast-like cells, in an attempt to elucidate its putative enhanced pathogenicity mechanisms. Therefore, two different concentrations of a heat-inactivated endodontic E. faecalis isolate (2 × 10(6) or 2 × 10(8) CFU/ml) were incubated with ovine osteoblast-like cells for 7 and 14 days, respectively. Cells without antigen served as control. The effects of antigen on cell growth were evaluated by a proliferation assay (EZ4U). Furthermore, the assessment of alkaline phosphatase (ALP) activity, calcium deposition, and osteocalcin (OCN) gene expression through quantitative real-time PCR determined the degree of osteogenic cell differentiation. Scanning electron microscopy (SEM) was also performed to detect alterations in cell morphology. Interestingly, although highly concentrated E. faecalis increased cellular reproduction after 14 days, ALP activity and OCN gene expression decreased in an antigen concentration-dependent and incubation time-independent way. SEM images revealed E. faecalis adhesion on cells, a fact that might contribute to its virulence. These results suggest that E. faecalis stimulated cell multiplication, whereas it likely restrained cell differentiation of ovine osteoblast-like cells. In conclusion, the presence of E. faecalis in root canals may negatively affect periapical new bone formation, and thus, the healing of periapical lesions.

Periapical bone defects of root filled teeth with persistent lesions evaluated by cone-beam computed tomography

To evaluate and categorize the bone defects of root filled teeth with persistent periapical lesions by cone-beam computed tomography (CBCT). Slice images of 532 teeth with persistent periapical lesions were obtained by CBCT in 427 patients and were examined by two endodontists. The periapical lesions were categorized into five types according to the characteristics of the bone defect based on CBCT images. The prevalence of each type was determined and analysed statistically at a 5% significance level using logistic regression. Of the 532 teeth analysed, 67% had buccal or labial bone plate defects (type II), 4% palatal or lingual bone plate defects (type III), 7%'through and through' defects (type IV) and 10% apical root protrusions from the bone plate (type V). Mandibular teeth had a significantly greater prevalence of type I lesions (P=0.0005) and a significantly lower prevalence for types IV (P=0.041), V (P=0.001), V-1 (P=0.015) and V-2 (P<0.001) as compared to maxillary teeth. CBCT accurately identified the type of periapical bone defect in persistent lesions. Because 10% of the teeth had apical root protrusions, which could not be identified by periapical radiography, the diagnostic information obtained by CBCT was an essential component of the treatment planning process.

Histopathological profile of surgically removed persistent periapical radiolucent lesions of endodontic origin

To determine the types of periapical lesions associated with root filled teeth with persistent periapical pathosis that required surgical treatment based on specific inclusion and exclusion criteria. Periapical lesions from a consecutive clinical sample of 100 patients were examined histopathologically to determine a definitive diagnosis. Females were more represented (n = 56), the average age was 46.5 years and there were no age differences between gender or lesion type. A diagnosis of periapical granuloma was the most common finding with a similar number present in females (n = 40) and males (n = 37). A cyst was present in 18% of the cases with a majority of females (n = 12) represented in the sample. Evidence of foreign material, with an appearance consistent with endodontic sealer materials, was seen in 25 periapical granulomas, two cysts and one scar. Two periapical scars were seen, one had a history of apicectomy and amalgam root-end filling while the other was associated with extruded root filling material. By using defined clinical inclusion and exclusion criteria a predictable clinical diagnosis of a persistent periapical lesion due to endodontic origin can be reliably made. Periapical granulomas and cysts were the most common periapical lesions of endodontic origin associated with persistent periapical pathosis with the overall incidence of periapical cysts similar to previous studies. The presence of endodontic material in a high proportion of periapical lesions suggests a cause-effect association with the inference that clinicians should employ canal preparation techniques that limit apical extrusion of material.

Bacterial diversity in persistent periapical lesions on root-filled teeth

Background: The purpose of this study was to analyze the bacterial diversity in persistent apical lesions on root-filled teeth by using culture-independent molecular methods.Design: Twenty surgically removed apical lesions from therapy-resistant teeth were examined for the presence of bacterial DNA using PCR targeting the 16s ribosomal RNA gene, followed by cloning and sequencing.Results: Bacterial DNA was detected in 17 of the 20 samples (85%). A total of 236 clones were analyzed. Seven different bacterial phyla were represented and a total of 75 different bacterial taxa were identified; 36% of the species have not yet been cultivated. Commonly detected bacterial species included Fusobacterium spp., Prevotella spp., Tannerella forsythia, Porphyromonas endodontalis, Treponema denticola, Bacteroidetes spp., Peptostreptococcus spp., and Streptococcus spp.Conclusions: A wide range of bacteria was identified in periapical lesions on therapy-resistant teeth. These bacteria may contribute in the etiology of periapical infection and impede healing of these lesions.

Residual bacteria in root apices removed by a diagonal root‐end resection: a histopathological evaluation

To assess bacteria in the apical portion of the root end after 45 degrees root-end resection in teeth with persistent periapical lesions. The study included 27 apical root segments from patients with persistent periapical lesions. Histological sections of the coronal part of the amputated root segment were stained with Brown and Brenn to detect the presence of bacteria in the main root canal and/or in irregular root spaces and dentinal tubules. The quality of each root canal filling was evaluated using preoperative radiographs of filling, length of root filling as assessed from the distance between its apical end and the radiographic apex, diameter of apical preparation, and presence of apical perforations or deviations from the root canal. Two endodontists, blinded to the bacteriological results, independently evaluated the radiographs. Bacteria were present in 23 (85.2%) specimens: five in only the main canal (21.7%), 10 in only the dentinal tubules and irregular spaces (43.5%), and eight in both irregular spaces and dentinal tubules and in the main root canal (34.8%). No correlation was found between the technical quality of the root filling assessed radiographically and bacterial presence in the central canal or irregular areas. Infected irregular areas were found in the root tips of teeth with persistent periapical lesions. This was found regardless of the radiographic quality of the root filling. Diagonal, 45 degrees root-end resection may expose such contaminated irregularities to the periapical tissue.

Reconsideration of treatment protocol on the reduction ofEnterococcus faecalisassociated with failed root canal treatment

Microorganism survived in the root canal after root canal cleaning and shaping procedure is a main cause of root canal treatment failure. There are several mechanisms for the bacteria to survive in the root canal after chemomechanical preparation and root canal irrigation. Bacteria organized as biofilm has been suggested as an etiology of persistent periapical lesion. Recent studies were focus on removal of Enterococcus faecalis biofilm due to the report that the persistence of this bacteria after root canal treatment may be associated with its ability to form biofilm. Several investigations demonstrated that current root canal treatment protocol including use of NaOCl, EDTA and Chlorhexidine as irrigants is quite effective in eliminating E. faecalis biofilm. However, this microorganism still can survive in inaccessible areas of root canal system and evade host immune response, suppress immune activity and produce biofilm. Up to date, there is no possible clinical method to completely get rid of bacteria from the root canal. Once the root canal treatment failure occurred, and conventional treatment incorporating current therapeutic protocol has failed, periapical surgery or extraction should be considered rather than prolong the ineffected retreatment procedure. [J Kor Acad Cons Dent 33(6):560-569, 2008]

Periopathogenic Bacteria in Persistent Periapical Lesions: An In Vivo Prospective Study

The aim of this in vivo prospective study was to detect the presence of periopathogenic bacteria in persistent periapical lesions and to compare the reliability of two different methods: anaerobic culture and the DNA hybridization technique. Samples were obtained from 24 patients with persistent periapical lesions referred for surgical endodontic treatment. A sterile paper point was inserted into the periapical lesion for 10 seconds. The point was stored in sterile transfer tubes and analyzed by DNA hybridization. Tissue samples were transported in transfer medium and analyzed further using anaerobic culture. At least one periodontal pathogenic bacterium was found in seven of 24 cases. Bacterial species present were Treponema denticola (three cases), Porphyromonas gingivalis (three cases), Tannerella forsythensis (four cases), Prevotella intermedia (one case), and Actinobacillus actinomycetemcomitans (three cases). No particular signs or symptoms were associated with the presence of these bacterial species. Anaerobic culture failed to identify any of the periopathogenic bacteria. Periodontal pathogenic bacterial DNA can be detected in persistent periapical lesions. Anaerobic cultures failed to detect the periodontal pathogenic bacteria in positive hybridization assays, suggesting that standard culture methods lack sensitivity or that hybridization assays are flawed with low specificity. The clinical significance of the presence of bacterial DNA in persistent periapical lesions remains to be determined.

Calcium hydroxide barrier over the apical root‐end of a type III dens invaginatus after endodontic and surgical treatment

To report the simultaneous endodontic and surgical treatment of a tooth associated with Oehlers type III dens invaginatus and a persistent periapical lesion, which comprised root-end resection, root-end filling and application of a calcium hydroxide barrier placed on the resected dentine surface. Three root canals were identified in a tooth with a type III dens invaginatus, which presented with a necrotic pulp, wide foraminal opening and extensive periapical lesion, and with a previous history of acute abscess, intracanal exudate and fistula. After root canal preparation followed by intracanal application of calcium hydroxide pastes, the clinical-pathological status persisted. After periapical curettage and root-end resection, the root canals were filled, followed by root-end filling with Sealer 26 mixed with zinc oxide powder to a clay-like consistency. Calcium hydroxide paste was then applied over the exposed dentinal surface forming a covering over the root apex. At the 20-month follow-up examination the patient had no symptoms and no fistula; advanced periapical bone repair was obvious on the radiograph. Because of the variable morphology and extent of invagination, type III dens invaginatus represents a challenge for conventional treatment, often leading to the need for a surgical approach. Sealer 26 thickened with zinc oxide powder provided satisfactory clinical properties for use as a root-end filling material. Application of a calcium hydroxide barrier over the resected root-end is a potential treatment option to encourage tissue repair.

Endoscope assisted endodontic surgery

Periradicular surgery, assisted by an endoscope was performed on patients with persistent periapical lesion of endodontic origin, which were not responding to conventional root canal therapy. The objective of using endoscope was to use a cost effective alternative to surgical microscope for diagnosis, illumination and magnification of the surgical field. Endoscope helped in the assessment of the extent, direction and depth of the lesion. It provided excellent illumination, magnification of the surgical field including the root apices and the area around the root apices.

3 難治性根尖性歯周炎から分離されたバイオフィルム様構造をもつ好気性有芽胞グラム陽性桿菌の同定と性状(第498回 大阪歯科学会例会)

3 難治性根尖性歯周炎から分離されたバイオフィルム様構造をもつ好気性有芽胞グラム陽性桿菌の同定と性状(第498回 大阪歯科学会例会)

A spore-forming Gram-positive aerobic rod isolated from a persistent periapical lesion has biofilm-like structures

A spore-forming Gram-positive aerobic rod isolated from a persistent periapical lesion has biofilm-like structures

Cultivable microbial flora associated with persistent periapical disease and coronal leakage after root canal treatment: a preliminary study

To identify the cultivable bacterial flora in root filled teeth with persistent periapical lesions and to locate their distribution within the root canal system using an in vitro sampling protocol. Eight freshly extracted root filled teeth were collected from the Oral and Maxillo-facial Surgery Department, Eastman Dental Hospital. Seven teeth were associated with persistent apical periodontitis and also showed evidence of coronal leakage. Teeth were transferred to an anaerobic chamber immediately after careful extraction and sectioned transversely to give a crown (in all but one case) and two root segments (coronal and apical). Two samples were obtained from each segment, one from dentine and the other from the restoration or gutta-percha (GP) root filling (46 sites in total). The samples were dispersed, serially diluted and cultured on blood agar and fastidious anaerobic agar (with 5% defibrinated horse blood). The primary growth was subcultured to obtain pure isolates, which were identified by routine microbiological techniques and commercial enzyme tests. A total of 252 strains were isolated from all the teeth. Of all the isolates, the most prevalent bacteria were Gram-positive facultative anaerobes 189/252 (75%) with staphylococci (48/252, 19%), streptococci (44/252, 17%), enterococci (20/252, 8%) and Actinomyces species (20/252, 8%) being found in most of the teeth (6/8, 6/8, 5/8, 5/8 and 7/8, respectively). Of the obligate anaerobes (17%), peptostreptococci (7%) were also present in most teeth (7/8). A statistical association between bacterial flora and site (crown/coronal/apical) or surface (dental/GP/restoration) could not be shown. The predominant group of bacteria in root filled teeth with persistent apical periodontitis and coronal leakage was Gram-positive facultative anaerobes of which staphylococci followed by streptococci and enterococci were the most prevalent.

Sonicated Extract of Enterococcus faecalis Induces Irreversible Cell Cycle Arrest in Phytohemagglutinin-Activated Human Lymphocytes

The purpose of this study was to examine whether the sonicated extract of Enterococcus faecalis (SEF) alters the cell cycle transition of lymphocytes and thus regulates the fate of the arrested cells. Human lymphocytes were activated by phytohemagglutinin in the presence or absence of SEF, and cell cycle was assessed by flow cytometry. Seventy-two hours after activation with phytohemagglutinin, cells were activated from G0/G1 to S (6.1%) and G2/M (3.8%) phases of the cell cycle. In contrast, pretreatment with SEF resulted in 90.5% of cells remaining in G0/G1, and cell cycle progression to the S and G2/M phases was consequently inhibited. Caspase assay demonstrated that SEF-treated cells exhibited significantly increased apoptosis (56.7%) compared with phytohemagglutinin alone (28.1%). We propose that if this irreversible cell cycle arrest induced by E. faecalis occurs in vivo, it may result in local immunosuppression and contribute to the pathogenesis of endodontic failure. Our findings that E. faecalis can inhibit lymphocyte responses may be of particular relevance to the pathogenesis of endodontic failure. Although the immunologic mechanism involved in the pathogenesis of persistent periapical lesion is not clearly defined, it is reasonable to predict that the altered immune reaction may be linked to the immunosuppressive potential of E. faecalis or other oral bacteria.

The perceived benefit of endodontic retreatment.

There is substantial variation amongst dentists in the management of symptom-free periapical lesions in root-filled teeth. It has been suggested that this variation can be understood as clinicians' choice of different cut-off points on a continuous periapical health scale (the 'Praxis Concept (PC) theory'). Based on this suggestion, an individual's inclination to propose retreatment can be expressed in the Retreatment Preference Score (RPS). In the present study it was hypothesized that: (i) the PC theory is valid amongst experienced endodontists; and that (ii) interindividual variation in RPS can be explained by a corresponding variation in the perceived benefit of endodontic retreatment. The RPS was determined for 16 experienced Swedish endodontists. The retreatment benefit (RTB) was defined as the gain in utility when a root-filled tooth with a persistent periapical lesion ('health state B') moved to a state where the lesion had healed ('health state A'). For each individual the utility values of the two health states were measured by means of the standard gamble technique. The RPS and RTB were found to be subjected to substantial inter- and intrarater variation. The decision makers acted in accordance with the PC theory. No significant correlation between RPS and RTB was detected. Findings suggest that the PC theory is valid amongst endodontic experts. The study did not support the notion that the more potential utility that could be produced, the more the individual dentist should tend to perform retreatment. However, alternative consequentialist strategies focusing low risk taking may be involved.

Persistent periapical radiolucencies of root-filled human teeth, failed endodontic treatments, and periapical scars

Objective. This report describes 6 cases that demonstrate persistent periapical radiolucent lesions after conventional root canal treatment. Study Design. Six teeth that had conventional root canal treatment or re-treatment with nonresolving periapical radiolucencies underwent periapical surgery. Biopsies were obtained and analyzed descriptively by correlative light and transmission electron microscopy for general features and microbial findings. Results. Three findings were identified: periapical lesions with persisting infection in the apical root canal system (2 cases); a cyst (1 case); and periapical healing by scar tissue formation (2 cases). Conclusions. These results confirm previous observations that associated factors in the failure of endodontic treatment include persistent intraradicular infection and periapical cysts. In addition, unresolved periapical radiolucencies may occasionally be due to healing by scar tissue, which may be mistaken as a sign of failed endodontic treatment. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1999;87:617-27)

Immunobiological activities of bacteria isolated from the root canals of postendodontic teeth with persistent periapical lesions

Although intraradicular bacteria are widely considered to be the primary etiological agents of periapical lesions, the immunobiological properties of the species in question are not adequately known. The aim of this study, therefore, was to investigate the pathobiological properties of the 10 most frequently isolated endodontopathic bacterial species. Using cellular components of the pathogens obtained by sonic extraction, we have investigated their ability to induce monocyte migration, interleukin 1 production, mitogenic responses of lymphocytes, and the polyclonal activation of B lymphocytes. It was found that all of the tested species enhanced the migration of monocytes and induced mitogenesis in B lymphocytes. The polyclonal activation of B cells and the induction of interleukin 1 by monocytes were found to be stronger in Gram-negative anaerobes. Furthermore, all of the tested species excluding Bacteroides oralis were poor T cell mitogens. These findings show that a wide range of pathobiological properties are attributable to the most frequently isolated endodontic pathogens. It thus seems plausible that a battery of complex immunological responses induced by such microbes lead to the formation of persistent periapical lesions.

Periapical actinomycosis: clinical considerations

Summary The preceding account has documented a case of actinomycosis simulating a periapical inflammatory condition. This case exemplifies our contention that a biopsy should be performed on any persistent periapical lesion when a clinical history of a chronic draining sinus tract associated with bone destruction exists, and a culture should be performed to establish a definitive diagnosis of a specific microbial organism such as Actinomyces israelii.