Endodontic Lesions Research Articles

Specificity of the oral microflora in dentinal caries, endodontic infections and periodontitis

The use of culture-independent molecular methods for the characterisation of the oral microflora in health and disease is revolutionising our understanding of the microbial ecology of the mouth. In addition, the use of 16S rRNA gene sequence analysis is allowing more precise identification of oral bacteria compared with that obtained using conventional phenotypic tests. The aim of this study was to use a combination of cultural and culture-independent methods to characterise the microflora in dentinal caries, endodontic lesions and periodontal pockets. Samples were cultured under aerobic and anaerobic conditions and randomly selected isolates were identified by 16S rRNA gene sequence analysis. In addition, DNA was extracted directly from the samples, 16S rRNA genes amplified by PCR and the amplified genes cloned to create Escherichia coli libraries. 3592 clones and isolates were sequenced and identified. 265 taxa, identified to species-level, were represented and belonging to 9 phyla: Actinobacteria, Bacteroidetes, Chloroflexi, Firmicutes, Fusobacteria, Proteobacteria, Spirochaetes, Synergistes and candidate Division TM7. 62 taxa were found in the endodontic samples, 98 in the carious lesions while the periodontal samples were the most species-rich with 161 taxa present. 15 taxa were found in both the caries and endodontic samples, 17 in the caries and periodontal samples and 21 in the endodontic and periodontal samples. Only 4 taxa were found in all three sample sets. In conclusion, the oral microflora is highly species-rich and the bacterial communities associated with the common dental diseases are specific to those diseases.

Porphyromonas gingivalis, Porphyromonas endodontalis, Prevotella intermedia and Prevotella nigrescens in endodontic lesions detected by culture and by PCR

he aim of this study was to investigate the presence of four black-pigmented bacteria, Porphyromonas gingivalis, Porphyromonas endodontalis, Prevotella intermedia and Prevotella nigrescens, in endodontic infections by culture and polymerase chain reaction (PCR) analyses. Microbial samples were obtained from 50 teeth with untreated necrotic pulps (primary infection) and from 50 teeth with failing endodontic treatment (secondary infection). Microbiological strict anaerobic techniques were used for serial dilution, plating, incubation, and identification. For PCR detection, the samples were analyzed using species-specific primers of 16S rDNA and the downstream intergenic spacer region. Culture and PCR detected the test species in 13/100 and 50/100 of the study teeth, respectively. The organisms were cultured from 11/50 (22%) of primarily infected root canal samples and from 2/50 (4%) of secondary root canal samples. PCR detection identified the target species in 32/50 (64%) and 18/50 (36%) of primary and secondary infections, respectively. P. gingivalis was rarely isolated by culture methods (1%), but was the most frequently identified test species by PCR (38%). Similarly, P. endodontalis was not recovered by culture from any tooth studied, but was detected by PCR in 25% of the sampled teeth. PCR-based identification also showed higher detection rates of P. intermedia (33%) and P. nigrescens (22%) than culture (13%). In conclusion, P. gingivalis, P. endodontalis, P. intermedia, and P. nigrescens were identified more frequently in teeth with necrotic pulp than in teeth with failing endodontic treatment. Also, a higher frequency of black-pigmented species was detected by PCR than by culture.

Early Loading of Interforaminal Implants Immediately Installed after Extraction of Teeth Presenting Endodontic and Periodontal Lesions

Infection in tooth extraction sites has traditionally been considered an indication to postpone implant insertion until the infection has been resolved. The aim of this study was to evaluate the survival rate of early-loaded implants placed immediately after extraction of teeth with endodontic and periodontal lesions in the mandible. Twenty patients in need of mandibular implant treatment and with teeth showing signs of infection in the interforaminal area were included in the study. The patients received four to six implants (Brånemark System, Nobel Biocare AB, Göteborg, Sweden) in or close to the fresh extraction sockets and received a provisional prosthesis within 3 days. Final prostheses were delivered after 3 to 12 months. The surgical protocol paid special attention to the preservation of high implant stability and control of the inflammatory response. The patients were followed up for 15 to 44 months. No implants were lost, resulting in a 100% survival rate. A mean marginal bone loss of 0.7 mm (SD 1.2 mm) was registered during the observation period. No signs of infection around the implants were detected at any follow-up visit. A high survival rate can be achieved for immediately placed and early-loaded implants in the mandible despite the presence of infection at the extracted teeth.

Isolation and identification of bacteria from the root canal of the teeth diagnosed as the acute pulpitis and acute periapical abscess

The aim of this study was to identify the bacteria isolated from acute endodontic lesions by cell culture and 16S rDNA sequencing. The necrotic pulpal tissue was collected from 17 infected root canals, which were diagnosed as being either an acute pulpitis or acute periapical abscess. Samples were collected aseptically from the infected pulpal tissue of the infected root canals using a barbed broach and a paper point. The cut barbed broaches and paper points were transferred to an eppendorf tube containing 500 ul of 1 XPBS. The sample solution was briefly mixed and plated onto a BHI-agar plate containing sheep blood. The agar plates were incubated in a anaerobic chamber for 7 days. The bacteria growing on the agar plate were identified by 16S rRNA coding gene (rDNA) cloning and sequencing at the species level. Among the 71 colonies grown on the agar plates, 56 strains survived and were identified. In dental caries involving the root canals, Streptococcus spp. were mainly isolated. Actinomyces, Clostridia, Bacteroides and Fusobacteria were isolated in the periapical lesion without dental caries. Interestingly, two new Actinomyces spp. (ChDC B639 and ChDC B631) were isolated in this study. These results showed that there was diversity among the species in endodontic lesions, This suggests that an endodontic infection is a mixed infection with a polymicrobial etiology. These results may offer the bacterial strains for pathogenesis studies related to an endodontic infection.

Management of Periodontitis Associated with Endodontically Involved Teeth: A Case Series

The pulp and the periodontal attachment are the two components that enable a tooth to function in the oral cavity. Lesions of the periodontal ligament and adjacent alveolar bone may originate from infections of the periodontium or tissues of the dental pulp. The simultaneous existence of pulpal problems and inflammatory periodontal disease can complicate diagnosis and treatment planning. The function of the tooth is severely compromised when either one of these is involved in the disease process. Treatment of disease conditions involving both of these structures can be challenging and frequently requires combining both endodontic and periodontal treatment procedures. This article presents cases of periodontitis associated with endodontic lesions managed by both endodontic and periodontal therapy.

Furcation canals of the maxillary fourth premolar and the mandibular first molar teeth in cats.

The furcation region morphology was evaluated in 103 mature feline carnassial teeth (54 maxillary fourth premolar and 49 mandibular first molar teeth). Patent furcation canals were present in 27.2% of teeth. No significant difference (p = 0.88) in distribution of this anatomical variation was found between maxillary fourth premolar and mandibular first molar teeth. The mean width of these furcation canals was 104.0 microns with two-thirds of the canals having a buccal orientation. The presence of furcation canals could be a factor in the etiopathogenesis of feline dental resorptive lesions, as well as a characteristic to be considered in the diagnosis, prognosis, and treatment of endodontic or periodontic-endodontic lesions in cat teeth.

Extraoral Sinus Tract Misdiagnosed as an Endodontic Lesion

The extraoral sinus tract may occur as a result of an inflammatory process associated with a necrotic pulp. However, several non-odontogenic disorders may also produce an extraoral sinus tract. Thus, the differential diagnosis of this clinical finding is of paramount importance in providing appropriate clinical care because misdiagnosis of this condition may result in healing failure or unnecessary treatment. This case report of a 19-yr-old male patient describes an extraoral cutaneous sinus tract misdiagnosed as an endodontic lesion. Consequently, the patient underwent unnecessary exploratory procedures and antibiotic therapy. Identification of the inflammatory source of the lesion and removal of the affected tissue led to tissue healing.

The evolving new understanding of endodontic infections

The science of oral microbiology is in a period of change from the era of bacterial cultivation to an era of molecular genetic methods and techniques. Already a significant body of new knowledge exists with regard to the oral flora in health and disease. Inevitably, this new knowledge has led to a better understanding of many oral diseases. In endodontics, the prevailing concepts are still to a great extent based on the results of the classical cultivation studies. However, a few groups have started to use molecular methods, and a new understanding of endodontic infections is presently evolving. Thus, the root canal infection clearly is more complex than revealed by cultivation methods alone, and both previously unidentified and uncultivable microorganisms have been detected by molecular methods. A reasonable estimate at present is that the infected root canal contains, not less than 10, but rather between 10 and 50 bacterial species which coincide well with the number of bacterial species normally found in a dental plaque sample and at different sites in the oral cavity. A further interesting finding in the studies using molecular techniques is that the microbiota of the infected root canal appears to be very similar to the flora of the periodontal pocket in patients with active periodontal disease. With regard to infection of periapical lesions in patients with asymptomatic apical periodontitis, electron microscopic and molecular methods have confirmed our cultivation findings that this is a common occurrence. Mature biofilms have been demonstrated on the external surfaces of root tips and in the form of sulfur granules within periapical granulomas. As in dental plaque, Actinomyces species appear to have a special role as scaffold builders in the development of sulfur granules. Other bacteria are then attracted to the site and a multibacterial granule (biofilm) develops. In addition, in situ hybridization studies show a variety of different bacteria and bacterial morphotypes in periapical lesions. With DNA–DNA hybridization between 11and 39 bacterial species have been recognized in the lesions, again confirming that in patients with active disease, the microbiotas of endodontic and periodontal infections are very similar. Thus, the recent findings demonstrate and confirm that the periapical endodontic lesion is not as hostile to microorganisms as many have thought. As clinicians we have to understand and accept that an infection might not be limited to the root of the tooth, but include the periapical lesion as well.

Expression of MHC Class II, CD70, CD80, CD86 and pro-inflammatory cytokines is differentially regulated in oral epithelial cells following bacterial challenge.

Oral epithelium may play a regulatory role in local immune responses when interacting with bacteria. The present study was undertaken to investigate the effects of selected bacterial pathogens found in periodontal and endodontic infections on oral epithelial cells. Expression of cell surface molecules (major histocompatibility complex (MHC) Class II, CD54, CD70, CD80 and CD86) and secretion of inflammatory cytokines (interleukin (IL)-1beta, IL-6, and tumor necrosis factor (TNF)-alpha) in response to selected bacterial challenge were examined on an immortalized oral epithelial cell line, HOK-18A and a skin epithelial cell line, HaCaT. Actinomyces viscosus, Actinomyces israelii, Fusobacterium nucleatum lipopolysaccharide (LPS) or primary human periradicular exudate from a granuloma were co-cultured with epithelial cells for 4 or 24 h. Subsequently, cell surface expression of MHC Class II, CD54, CD70, CD80 and CD86, along with pro-inflammatory cytokine levels were determined using flow cytometry, ELISA and RT-PCR. Results indicated that the selected oral bacteria have greater effects on oral versus skin epithelial cells. F. nucleatum increased MHC Class II and CD54 (ICAM-1) cell surface expression on HOK-18A and HaCaT cells. A. israelii also had enhancing effects on the expression of CD54 and MHC Class II. A. israelii and LPS induced a 2.8-fold (P < 0.001) and 4.4-fold (P < 0.005) TNF-alpha secretion, respectively, while F. nucleatum and LPS induced a 10-fold (P < 0.0004) and 6-fold (P < 0.01) IL-1beta secretion, respectively by HOK-18A. Interestingly, CD70, CD80, and CD86 were generally decreased upon bacteria and LPS challenge on HOK-18A. The effects of increased MHC Class II and decreased CD70 were also evident with challenge of human periradicular exudate on HOK-18A. The implications of the study are unique in that oral epithelial cells may play both activating and inhibitory roles in the host immune response towards infection by oral bacteria. We introduce a concept of 'dormancy' where the differential expression of key cell surface antigens on oral epithelial cells may keep the recruited immune effector cells in a state of unresponsiveness, thus contributing to the long term quiescent period observed in many periodontal and endodontic lesions.

An Easy Solution to Endodontic Problems?

Treatment of Combined Endodontic Periodontic Lesions by Intentional Replantation and Application of Hydroxyapatites. L. Yu, B. Xu and B. Wu. Dental Traumatology 2003; 19: 60–63.

Cytomegalovirus and Epstein-Barr virus DNA transcription in endodontic symptomatic lesions.

Productive Herpesviridae infections are implicated in the etio-pathogenesis of aggressive periodontitis. However, virtually nothing is known about a possible role of herpesviruses in pulpal and periapical pathosis. This study employed a cDNA analysis to determine transcription of human cytomegalovirus (HCMV), Epstein-Barr virus (EBV) and herpes simplex virus (HSV) in 14 recalcitrant periapical lesions and in 2 periapical healthy control sites. Periapical samples were collected in conjunction with periapical surgery and kept frozen until virologic examination. RNA was isolated from periapical tissue by using a guanidinium isothiocyanate-acid phenol procedure (TRIZOL LS Reagent, GIBCO BRL, Rockville, MD). cDNAs were amplified by means of oligonucleotides targeting highly conserved regions of the test viruses and the RT-PCR-100 amplification kit (Sigma-Aldrich, St Louis, MO). Standardization of PCR primer sensitivity and validation was carried out according to established methods. Amplification products were identified by agarose gel electrophoresis. HCMV transcript was detected in 12 of 13 symptomatic and in 1 asymptomatic periapical lesion. EBV transcript was demonstrated in 8 of the 13 symptomatic lesions but not in the asymptomatic periapical lesion. HCMV and EBV dual transcription occurred at higher frequency in periapical lesions showing radiographic bone destruction of 5 mm x 7 mm or larger than in smaller size lesions (P = 0.03; Chi-squared test). No HCMV or EBV transcription was identified in the 2 healthy control sites. HSV transcript was not detected in any study site. The present data suggest that HCMV or EBV infections participate in the pathogenesis of periapical symptomatic lesions. Herpesviruses may produce periapical pathosis as a direct result of viral infection and replication, or as a consequence of virally induced impairment of the host defense and subsequent increased virulence of resident bacterial pathogens.

ANALISA URUTAN GEN 16S rRNA DARI BAKTERI ORAL YANG TIDAK DIKENAL

The purpose of this study was to identify five unknown bacterial strains by using 16S rRNA gene sequencing. These strains isolated from endodontic lesions and periodontal pocket are culture-difficult and inert in most biochemical tests, and could not be classified to any established bacterial species by conventional bacteriological method. In the present study, genomic DNA was extracted from the cultured bacterial cells with InstaGene (BIO-RAD), and the 16S rRNA gene was amplified by PCR with universal primers (27F and 1492R) and Premix Taq (Ex Taq version, Takara), then was sequenced by using a Thermo Sequence Fluorescent Labelled Primer Cycle Sequencing Kit (Amersham) and an ALFexpress DNA sequencer (Pharmacin LKB). The segmented nucleotide sequences of 16S rDNA were integrated by using SEQMAN in LASERGENE computer program (DNASTAR). The 16S rDNA sequences of the unknown bacterial strain were applied to GenBank by using BLAST program to search the suspected bacterial species . The MEGALIGN search program showed that the sequence similarities were 89.5% - 91.3% to a type strain of Dialister pneumosintes among the established bacterial species. Based on the phylogenetic data, it is considered that the five unknown strains have to be presented a new bacterial species as Dialister-like bacterium.

Bacteria induce osteoclastogenesis via an osteoblast-independent pathway.

Bacteria or their products may cause chronic inflammation and subsequent bone loss. This inflammation and bone loss may be associated with significant morbidity in chronic otitis media, periodontitis, endodontic lesions, and loosening of orthopedic implants caused by lipopolysaccharide (LPS)-contaminated implant particles. Currently, it is not clear how bacteria or endotoxin-induced bone resorption occurs and what cell types are involved. Here we report that Porphyromonas gingivalis, a periodontal pathogen, and Escherichia coli LPS induce osteoclastic cell formation from murine leukocytes in the absence of osteoblasts. In contrast, stimulation with parathyroid hormone had no effect. These multinucleated, tartrate-resistant acid phosphatase-positive cells were positive for receptor activator of NF-kappaB (RANK), the receptor for osteoprotegerin ligand (OPGL), also known as RANK ligand (RANKL). Blocking antibodies demonstrated that their formation was dependent upon expression of OPGL and, to a lesser extent, on tumor necrosis factor alpha. Mononuclear cells represented a significant source of OPGL production. In vivo, P. gingivalis injection stimulated OPGL expression in both mononuclear leukocytes and osteoblastic cells. Thus, these findings describe a pathway by which bacteria could enhance osteolysis independently of osteoblasts and suggest that the mix of cells that participate in inflammatory and physiologic bone resorption may be different. This may give insight into new targets of therapeutic intervention.

Periapical central giant cell granuloma: a potential endodontic misdiagnosis.

This retrospective study ascertained the incidence and clinicopathologic features of central giant cell granulomas (CGCGs) associated with teeth with necrotic pulps or teeth that had received previous endodontic treatment and determined whether periapical CGCGs can result in endodontic misdiagnosis. Clinical and histopathologic data of biopsy specimens diagnosed as CGCG were collected from the archives of the Oral Pathology Laboratory, Temple University, and were reviewed. Over the 9-year period, 16 of 79 cases (20%) of CGCG were associated with a tooth that had a history of pulp necrosis. Of those, 14 (88%) were associated with previous root canal treatment. The data from this series of 79 cases of CGCG also showed that CGCGs were less common in women, less common before age 30, and did not cross the midline of the jaw as often as previously reported. Clinical and histopathologic data were compared from (1) CGCGs associated with teeth with vital pulps or that occurred in edentulous areas; (2) CGCGs associated with teeth with necrotic pulps; and (3) 194 cases of periapical granulomas and radicular cysts. These data strongly suggest that CGCGs associated with teeth with necrotic pulps are not directly related to periapical inflammation and may be misdiagnosed as endodontic lesions. Posttreatment follow-up and routine submission of periapical surgical specimens are emphasized.

Current practice in endodontics: 2. Diagnosis and treatment planning.

The aim of this series of six articles is to improve the quality of endodontic treatment in general dental practice by considering what is currently being taught in dental schools. This second article considers the accurate diagnosis of endodontic lesions, which frequently present as emergencies requiring prompt, rapid and efficient attention. The paper then presents the treatment normally indicated once a correct and accurate diagnosis has been made.

Assessment of periradicular microbiota by DNA-DNA hybridization.

– In the present study the “checkerboard” DNA‐DNA hybridization technique was used to identify bacteria in periapical endodontic lesions of asymptomatic teeth. Thirty‐four patients with root‐filled teeth and apical periodontitis were divided into two groups, each containing 17 patients. In Group 1, a marginal incision was performed during surgery to expose the lesion, and in Group 2, a submarginal incision was applied. The gingiva and mucosa were swabbed with an 0.2% chlorhexidine gluconate solution prior to surgery. Bacterial DNA was identified in all samples from the two groups using 40 different whole genomic probes. The mean number (±SD) of species detected was 33.7±3.3 in Group 1 and 21.3±6.3 in Group 2 (P<0.001). The majority of the probe‐detected bacteria were present in more lesions from Group1 than from Group 2. The differences were most notable for Campylobacter gracilis, Porphyromonas endodontalis, Propionibacterium acnes, Capnocytophaga gingivalis, Fusobacterium nucleatum ssp. nucleatum, Fusobacterium nucleatum ssp. polymorphum, Prevotella intermedia, Treponema denticola, Streptococcus constellatus and Actinomyces naeslundii I. Bacterial species such as Actinobacillus actinomycetemcomitans and Bacteroides forsythus were detected in more than 60% of the lesions from both groups. Also, P. endodontalis was abundant in periapical tissue. The data supported the idea that following a marginal incision, bacteria from the periodontal pocket might reach the underlying tissues by surgeon‐released bacteremia. The study provided solid evidence that bacteria invade the periapical tissue of asymptomatic teeth with apical periodontitis. The detection of much more bacteria with the “checkerboard” DNA‐DNA hybridization method than has previously been recovered by anaerobic culture indicated that the endodontic (and periodontal) microfloras should be redefined using molecular methods.

The Radicular Groove: Its Potential Clinical Significance

This report examines three clinical cases of root-filled teeth with primary endodontic lesions. During endodontic surgery, an area of incomplete root bifurcation beginning in the coronal or middle third of the root surface and terminating at or near the apical foramen were observed. The radicular grooves of two teeth were eliminated using a round bur ("saucerization"), and the resulting defect was filled with a bone substitute or calcium sulfate and covered by an absorbable collagen membrane. The other tooth was extracted, the groove was eliminated with a similar technique, and the tooth was replanted. Bacteria have been reported in chronic apical lesions. Our observations suggest that after conventional endodontic therapy, the etiology of a nonresolving primary endodontic lesion may be bacteria of endodontic origin sequestered within the protective confines of an apical-radicular groove.

Consensus Report: Periodontic‐Endodontic Lesions

90 sive forms of periodontitis can gain access to pulpal tissues through accessory canals or the tooth apex and lead to pulpal infection. In those cases where there is any coalescence of endodontic and periodontal lesions, the group agreed that these situations should be termed, “Combined Periodontal-Endodontic Lesions.” This classification is not based on the initial etiology of the lesion. Either the periodontal or endodontic lesion may be the cause or the result of the other or both may develop independently. Therefore, the group recommended the following classification:

A lesion of endodontic origin misdiagnosed as a globulomaxillary cyst

This report presents a case of a lesion originating from a pulpless central incisor misdiagnosed as a globulomaxillary cyst. The initial diagnosis of globulomaxillary cyst was made solely from radiographs by observing an almond-shaped radiolucency between the lateral incisor and cuspid. No pulp testing was performed before surgical removal of the lesion. The final diagnosis of an endodontic lesion caused solely by a pulpless central incisor was complicated by the initial lack of a pulpal response from the lateral incisor next to the surgical site. By delaying the start of endodontic treatment, pulp sensibility returned to the lateral incisor and the diagnosis of an endodontic lesion caused only by a pulpless central incisor was confirmed.

Rapid canine retraction through distraction of the periodontal ligament

The process of osteogenesis in the periodontal ligament during orthodontic tooth movement is similar to the osteogenesis in the midpalatal suture during rapid palatal expansion. A new concept of “distracting the periodontal ligament” is proposed to elicit rapid canine retraction in 3 weeks. It is called dental distraction. Fifteen orthodontic patients (26 canines, including 15 uppers and 11 lowers) who needed canine retraction and first premolar extraction were included. At the time of first premolar extraction, the interseptal bone distal to the canine was undermined with a bone bur, grooving vertically inside the extraction socket along the buccal and lingual sides and extending obliquely toward the socket base. Then, a tooth-borne, custom-made, intraoral distraction device was placed to distract the canine distally into the extraction space. It was activated 0.5 to 1.0 mm/day immediately after the extraction. The anchor units were the second premolar and first molar. Cephalometric and periapical x-rays were taken before and after the canine retraction. Both the upper and lower canines were distracted bodily 6.5 mm into the extraction space within 3 weeks. New alveolar bone was generated and remodeled rapidly in the mesial periodontal ligament of the canine during and after the distraction. It became mature and indistinguishable from the native alveolar bone 3 months after distraction. During the distraction, 73% of the first molars did not move mesially and 27% of them moved less than 0.5 mm mesially within 3 weeks. The radiographic examination revealed that apical or lateral surface root resorption of the canine was minimal. No periodontal defect or endodontic lesion was observed throughout and after distraction. We concluded that the periodontal ligament could be rapidly distracted without complications. The rapid orthodontic tooth movement through distracting the periodontal ligament cannot be emulated by current conventional orthodontic concepts and methods. (Am J Orthod Dentofacial Orthop 1998;114:372-82)