Factors influencing the success of conventional root canal therapy--a five-year retrospective study

This retrospective study on the outcome of conventional root canal therapy was carried out on patients attending the Eastman Dental Hospital between 1970 and 1982. A minimum follow-up period of 5 years was required for patients to be included in the survey. The characteristics of the resulting sample group, the techniques for canal preparation and obturation and the obturating materials used were analysed. The type of obturating material used had no demonstrable effect on success rate but sex, age, preoperative vitality and periapical pathology were associated with significantly differing success rates. Technique also influenced success rate; the method of canal preparation and the position of the apical seal relative to the radiographic apex were both found to be significant. The overall success rate was 84.29%, representing 692 of 821 teeth included in the survey.

A prognostic model for assessment of the outcome of endodontic treatment: Effect of biologic and diagnostic variables

OBJECTIVE

Many biological variables, endodontic treatment factors, and restorative considerations have been suggested in the literature to affect the outcome of endodontic treatment. However, few attempts have been made recently to study these variables further. The purpose of this study was to identify the biologic and endodontic treatment-associated variables that are most predictive of treatment outcome for conventional endodontic therapy and to determine the magnitude of risk these variables pose on the outcome.

STUDY DESIGN

The population of this historical prospective cohort study comprised a total of 200 teeth with 441 root canals. Diagnostic and treatment information was abstracted from the original patient records. An endodontic follow-up examination was conducted 4 +/- 0.5 years after obturation. Each tooth/root was analyzed according to 3 indices of periradicular status at 2 time points. The main outcome measure was the presence of apical periodontitis. The criteria used for evaluation of the outcome were modified from Strindberg. Data were subjected to univariate and multivariate analysis. Logistic regression models were fit by using various clinical measures to determine which combination of biologic and treatment-associated factors best predicted treatment outcome.

RESULTS

The preoperative pulp diagnosis, the periapical diagnosis, the preoperative periapical radiolucency size, and the sex of the patients were revealed, by means of univariate analysis, to exert a significant influence on endodontic treatment outcome (P <.05). In the logistic regression model, the strongest effect on postoperative healing was the presence and magnitude of preoperative apical periodontitis. In the presence of this variable, no other factor contributed value to the prediction. The correct prediction of this model was 74.7% (P <.05).

CONCLUSION

The major biologic factors influencing the outcome of endodontic treatment appear to be the extent of microbiological insult to the pulp and periapical tissue, as reflected by the periapical diagnosis and the magnitude of periapical pathosis.

Endodontic perforations: their prognosis and treatment

Causes of tooth perforation include resorption, caries, and operator performance. The prognosis for a tooth with a perforation is related to the location of the perforation, negotiability of the canal, contamination, and treatment. Alternative treatment approaches include routine endodontic treatment, correction via the chamber, surgical correction, and stimulation of calcification. In most instances, a perforation can be treated so that satisfactory healing will occur.

Failures and healing in endodontically treated non-vital anterior teeth with posttraumatically reduced pulpal lumen

The aim of the present investigation was to assess the frequency of technical failures as well as the 4-year results of endodontic treatment in non-vital incisors with post-traumatically reduced pulpal lumen. In 54 teeth the smallest width of the root canal was measured and classified as 0. less than or equal 0.1, greater than 0.1- less than or equal to 0.2 or greater than 0.2 mm. The total frequency of failures was 20%. In upper incisors it was 15-17% in the classes up to a root canal width of 0.2 mm. In lower incisors with no or only partially visible root canal it was 71% and in the class up to 0.1 mm 10%, the difference being significant at the 5% level. The total frequency of healing after 4 years was 80%, while in teeth with a technical failure at the time of treatment the frequency was 50%. The difference between the group without and that with technical failures was statistically significant at the 5% level.

The predictive value of endodontic diagnostic tests

The diagnostic usefulness of common endodontic tests was evaluated through the retrospective analysis of studies in which histologic examinations were performed. In general, tests were able to adequately identify persons who were likely to be free of disease but were substantially less effective in identifying disease-positive persons. Thus, persons who are test-positive for irreversible pulpal disease are frequently disease-negative on the basis of histologic examination. These findings suggest that practitioners continue to use all available evidence in making a diagnosis of irreversible pulpal disease.

Pathologic interactions in pulpal and periodontal tissues

Both endodontic and periodontal disease are caused by a mixed anaerobic infection. The pathways for the spread of bacteria between pulpal and periodontal tissues have been discussed with controversy. This article is an attempt to provide a rational approach to the perio-endo/endo-perio question based on a review of the relevant literature. In the light of evidence, clinical concepts for the diagnosis and treatment of lesions involving both periodontal and pulpal tissues are discussed.

Relationship between periapical and periodontal status. A clinical retrospective study

The purpose of the present investigation was to explore possible relationships between clinical periodontal status in periodontally involved teeth with and without endodontic infection. The investigation was conducted as a retrospective study on a consecutive referral population. The periapical conditions in endodontically-involved single-rooted teeth from a selected patient sample were evaluated and correlated to their periodontal status. There was a significant correlation between periapical pathology and vertical bony destructions. An intra-individual comparison between pocket depth in teeth with and without periapical pathology showed that periapical pathology was significantly correlated to an increased pocket depth in the absence of a vertical bony destruction. It was concluded that an endodontic infection, evident as a periapical radiolucency, promotes periodontal pocket-formation on an instrumented marginal root surface and, consequently, should be regarded as a risk factor in periodontitis progression and be given appropriate consideration in periodontal treatment planning.

Axin2-expressing cells differentiate into reparative odontoblasts via autocrine Wnt/β-catenin signaling in response to tooth damage

In non-growing teeth, such as mouse and human molars, primary odontoblasts are long-lived post-mitotic cells that secrete dentine throughout the life of the tooth. New odontoblast-like cells are only produced in response to a damage or trauma. Little is known about the molecular events that initiate mesenchymal stem cells to proliferate and differentiate into odontoblast-like cells in response to dentine damage. The reparative and regenerative capacity of multiple mammalian tissues depends on the activation of Wnt/β-catenin signaling pathway. In this study, we investigated the molecular role of Wnt/β-catenin signaling pathway in reparative dentinogenesis using an in vivo mouse tooth damage model. We found that Axin2 is rapidly upregulated in response to tooth damage and that these Axin2-expressing cells differentiate into new odontoblast-like cells that secrete reparative dentine. In addition, the Axin2-expressing cells produce a source of Wnt that acts in an autocrine manner to modulate reparative dentinogenesis.

Comprehensive analysis of secondary dental root canal infections: a combination of culture and culture-independent approaches reveals new insights

Persistence of microorganisms or reinfections are the main reasons for failure of root canal therapy. Very few studies to date have included culture-independent methods to assess the microbiota, including non-cultivable microorganisms. The aim of this study was to combine culture methods with culture-independent cloning methods to analyze the microbial flora of root-filled teeth with periradicular lesions. Twenty-one samples from previously root-filled teeth were collected from patients with periradicular lesions. Microorganisms were cultivated, isolated and biochemically identified. In addition, ribosomal DNA of bacteria, fungi and archaea derived from the same samples was amplified and the PCR products were used to construct clone libraries. DNA of selected clones was sequenced and microbial species were identified, comparing the sequences with public databases. Microorganisms were found in 12 samples with culture-dependent and -independent methods combined. The number of bacterial species ranged from 1 to 12 in one sample. The majority of the 26 taxa belonged to the phylum Firmicutes (14 taxa), followed by Actinobacteria, Proteobacteria and Bacteroidetes. One sample was positive for fungi, and archaea could not be detected. The results obtained with both methods differed. The cloning technique detected several as-yet-uncultivated taxa. Using a combination of both methods 13 taxa were detected that had not been found in root-filled teeth so far. Enterococcus faecalis was only detected in two samples using culture methods. Combining the culture-dependent and –independent approaches revealed new candidate endodontic pathogens and a high diversity of the microbial flora in root-filled teeth with periradicular lesions. Both methods yielded differing results, emphasizing the benefit of combined methods for the detection of the actual microbial diversity in apical periodontitis.

Dental caries and pulpal disease

This article reviews the diagnostic process, from the first clinically evident stages of the caries process to development of pulpal pathosis. The caries diagnostic process includes 4 interconnected components-staging caries lesion severity, assessing caries lesion activity, and risk assessments at the patient and tooth surface level - which modify treatment decisions for the patient. Pulpal pathosis is diagnosed as reversible pulpitis, irreversible pulpitis (asymptomatic), irreversible pulpitis (symptomatic), and pulp necrosis. Periapical disease is diagnosed as symptomatic apical periodontitis, asymptomatic apical periodontitis, acute apical abscess, and chronic apical abscess. Ultimately, the goal of any diagnosis should be to achieve better treatment decisions and health outcomes for the patient.

Responses of immunocompetent cells to cavity preparation in rat molars: an immunohistochemical study using OX6-monoclonal antibody

Responses of immunocompetent cells, especially class II major histocompatibility complex (MHC) antigen-expressing cells, were investigated after cavity preparation in the erupted upper first molar teeth of rats, by immunohistochemistry using OX6-monoclonal antibody. In control teeth, OX6-immunopositive cells were predominantly located beneath the odontoblast layer in the dental pulp. Cavity preparation caused an acute edematous reaction between the injured odontoblasts and predentin, and most of OX6-immunopositive cells in the affected site shifted away from the pulp-dentin border. After 12-24 hours, many OX6-immunopositive cells accumulated along the pulp-dentin border and extended their cytoplasmic processes into the exposed dentinal tubules. After 72 hours, newly differentiated odontoblasts replaced the degenerated odontoblasts, and few OX6-immunopositive cells remained along the pulp-dentin border. Our data suggest that some of the class II MHC antigen-expressing cells in the dental pulp participate in the initial defense reaction and presumably serve as a biological sensor for the external stimuli arriving through the exposed dentinal tubules.

Comparison of clinical and histologic diagnoses in periapical lesions

OBJECTIVE

To determine the frequency with which histopathologic examination of periapical biopsy specimens contributed information not anticipated clinically.

STUDY DESIGN

Clinical and histopathologic information from 805 sequentially submitted periapical biopsy specimens over a 2-year period was compared. Clinical data included endodontic status, age and sex of patient, location of lesion, and submitting clinician. Histopathologic diagnoses were categorized as 1) sequelae of pulpal necrosis (SPN), 2) complicated SPN (CSPN) with infection or antral involvement, or 3) periapical lesions unrelated to pulpal necrosis (PLUPN).

RESULTS

Of the 805 cases, 788 (97.9%) were SPN, 9 (1.1%) were CSPN, and 8 (1%) were PLUPN, representing a range of locally aggressive but benign lesions and 1 malignancy. Comparison of clinical and histologic diagnoses indicated that the clinical interpretation was inaccurate in 4.1% of cases (suggesting SPN in PLUPN cases or PLUPN in SPN cases). In another 0.9% of cases, the histologic analysis (indicating CSPN) contributed additional information to the clinical diagnosis.

CONCLUSIONS

A histopathologic examination contributed clinically relevant information in 5.0% of submitted cases. General extrapolation of this figure is not possible. Theoretical considerations, which could positively or negatively bias this figure, are discussed.

Pulp changes after anterior mandibular subapical osteotomy in a primate model

Subapical osteotomy of the anterior mandible was carried out on 10 adult Macaca Irus monkeys with and without open bite. Teeth were extracted at 8 weeks, 12 weeks, 24 weeks and 1 year after surgery and the pulps examined histologically. No normal pulps were found. Progressive fibrosis and calcification was noted in all teeth. Patent pulp blood vessels were found up to 24 weeks after surgery. Pulp damage to teeth distal to the osteotomy site was found in 50% of cases. Control teeth extracted from the opposing jaw at the same intervals were all found to have normal pulps.