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Shearing bond strength of endodontic sealers to gutta-percha.

Strength of the bond of root canal sealers to gutta-percha seems to be an important property for maintaining the integrity of the apical seal. In the few studies published, different models and assessment methods were used. The purpose of our study was to adapt an effective and easily reproducible model and to test it on nine contemporary commercially available endodontic sealers. Gutta-percha disks with a diameter of 10 mm and thickness of 2 mm were prepared by warming gutta-percha cones and then fixed with plaster in 1-inch phenolic rings. Five-millimeter long sections of polyethylene tubing, filled with freshly mixed sealer, were placed on the gutta-percha and tested for shearing bond strength after setting. A custom-made holder was attached to the rings and placed in an Instron machine, which was activated at a cross-arm speed of 0.5 mm per minute. The bond strength ranged from 0 MPa to 6.4 MPa. The sealers were ranked, and those that did not differ statistically in their bond strength were grouped together. This model provides a simple and reproducible means for measuring the in vitro bond strength of endodontic sealers.

Adhesiveness↗

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.

Adolescent↗

Taurodontism: an endodontic challenge. Report of a case.

Taurodontism is a morphoanatomical change in the shape of a tooth, which usually occurs in multirooted teeth. An enlarged body and pulp chamber, as well as apical displacement of the pulpal floor, are characteristic features. Endodontic treatment of a taurodont tooth is challenging, because it requires special care in handling and identifying the number of root canals. A case of endodontic treatment of a maxillary first molar with taurodontism is presented.

Adult↗

Adhesion of endodontic sealers: scanning electron microscopy and energy dispersive spectroscopy.

The microscopic details of the debonded interfaces between endodontic sealers and dentin or gutta-percha were assessed in this study. Dentin, conditioned with 37% H3PO4 for 30 s, 25% citric acid for 30 s, 17% EDTA for 5 min, or a rinse with 10 ml of distilled H2O (control), and gutta-percha surfaces were coated with freshly mixed sealer: Grossman's sealer, Apexit, Ketac-Endo, AH Plus, RoekoSeal Automix, or RoekoSeal Automix with an experimental primer. The surfaces were pressed together and the sealers were allowed to set. After tensile bond strength testing, the morphological aspects of the fractured surfaces were assessed by scanning electron microscopy and energy dispersive spectroscopy. The energy dispersive spectroscopy successfully traced sealer components to the debonded surfaces. Some of the sealers penetrated into the dentinal tubules when the dentin surface had been pretreated with acids. However, these sealer tags remained occluding the tubules after bond failure in some instances only (Grossman's sealer, RoekoSeal Automix with an experimental primer, AH Plus/EDTA). Penetration of the endodontic sealers into the dentinal tubules when the smear layer was removed was not associated with higher bond strength.

Acid Etching, Dental↗

Patient safety during endodontic therapy using current technology: a case report.

It is an accepted safety practice to take precautions during endodontic treatment to prevent aspiration or swallowing of instruments (1). The placement of a rubber dam is considered the standard of care (2, 3). With the advent of new endodontic devices, new safety challenges have arisen and must be considered in addition to the placement of a rubber dam. A case report is presented that emphasizes the importance of patient safety and suggests precautions to prevent any safety-related mishaps during treatment.

Dental Instruments↗

Radiopacity of endodontic sealers: development of a new method for direct measurement.

Radiopacity is an essential attribute of endodontic filling materials. It is important to see clearly the root canal filling to detect its presence, extent, and apparent condensation. National and international standards require a minimal radiopacity equivalent to 3 or 4 mm of aluminum, yet some products made by reputed companies do not meet this requirement. The result may be unjustified downgrading of clinical cases. The purpose of this investigation was 2-fold: to develop a novel and easily reproducible technique for assessing the radiopacity of endodontic sealers and to apply it to measure the opacity of 21 current cements poured in 6- x 1-mm wells. As in the currently recommended technique, the standardized samples are radiographed alongside an aluminum stepwedge but instead of using an optical densitometer to measure the density and then calculate the radiopacity, the image is digitized. The gray pixel value of the test material is compared with the stepwedge, using computer software, to find the corresponding step. The opacity of the samples ranged from 1.6 mm to more than 11 mm of aluminum. The technique can be advanced to a dry, chemical-less variant by using radiation captors, as for periapical X-rays, instead of film.

Absorptiometry, Photon↗

Treatment outcome in endodontics: the Toronto Study. Phase 1: initial treatment.

This study assessed the 4- to 6-yr outcome of initial endodontic treatment during Phase 1 of the "Toronto Study" project. A total of 450 teeth were treated, alternating the "Schilder" technique and step-back with lateral condensation, and examined clinically and radiographically by an independent examiner. Apical periodontitis was recorded as absent (periapical index < 3) or present (periapical index > or = 3) and outcome dichotomized as "healed" (no apical periodontitis, no signs or symptoms) or "disease." Univariate, bivariate, and multivariate analyses were performed (p = 0.05) on 120 examined teeth. The "healed" rate (81% overall) was significantly higher for teeth treated without apical periodontitis (92%) than with apical periodontitis (74%). Several other factors were associated with healing rate differential of 10% or higher, but no statistical significance. This study confirmed apical periodontitis as the main prognostic factor in initial endodontic treatment. Continuation of the project will allow assessment of other prognostic factors with better power.

Chi-Square Distribution↗

Prevalence of odontogenic sinus tracts in patients referred for endodontic therapy.

The purpose of this study was to determine the prevalence of odontogenic sinus tracts in patients referred for endodontic therapy. Charts of 330 patients (393 permanent teeth) endodontically treated during a 10-month period were reviewed and data was collected. Among the 393 permanent teeth there were a total of 160 teeth with preoperative status of periradicular inflammation. Of 160 teeth with preoperative status of periradicular inflammation, 29 teeth (18.1%) had an odontogenic sinus tract, which correlates to almost one in five teeth with periradicular inflammation having a sinus tract.

Adolescent↗

Pain in endodontics. 1986.

A frequent problem in endodontics is the development of pain and swelling during or after endodontic therapy. Although the reasons for such exacerbations are not always clear, there are a number of hypotheses which will be discussed in this article.

History, 20th Century↗

Assessment of elemental composition, microstructure, and hardness of stainless steel endodontic files and reamers.

The purpose of this study was to determine the elemental composition, microstructure, and hardness of commercially available reamers, K files, and H files. Five instruments of each type from different manufacturers (Antaeos, FKG, Maillefer, Mani, and Micromega) were embedded in epoxy resin along their longitudinal axis. After metallographic grinding and polishing, the specimens were chemically etched and their microstructure investigated under an incident light microscope. The specimens were studied under a scanning electron microscope, and their elemental compositions were determined by energy dispersive X-ray microanalysis. The same surfaces were repolished and X-ray diffraction was performed. The same specimen surface was used for the assessment of the Vickers hardness (HV200) by using a microhardness tester with a 200-g load and 20-s contact time. The hardness results were statistically analyzed with two-way ANOVA and Tukey's test (a = 0.05). All files demonstrated extensively elongated grains parallel to longitudinal file axis because of cold drawing. The elemental composition of Maillefer and Mani reamers, Antaeos K files, and Mani H files were found in the range of AISI 303 SS, whereas all the rest were determined as AISI 304 SS. Two different phases (austenite SSt and martensite SSt) were identified with X-ray diffraction for all files tested. The results of hardness classified reamers in the following decreasing order (HMV200): Micromega = 673 +/- 29, Mani = 662 +/- 24, Maillefer = 601 +/- 34, Antaeos = 586 +/- 18, FKG = 557 +/- 19, and the K files (HV200): FKG = 673 +/- 16, Mani = 647 +/- 19, Maillefer = 603 +/- 41, Antaeos = 566 +/- 21, Micromega = 555 +/- 15, and the H files (HMV200): Mani = 640 +/- 12, FKG = 583 +/- 31, Maillefer = 581 +/- 5, Antaeos = 573 +/- 3, Micromega = 546 +/- 14. Although only two stainless steel alloys were used for the production of endodontic files, the differences in hardness are independent to the alloys used, implying that other factors, such as the production method or the thermomechanical history of the alloys, play an important role on the mechanical properties of endodontic files.

Acid Etching, Dental↗

Assessment of endodontically treated teeth adjacent to proposed implant sites.

Many partially dentate dentitions are now being restored using dental implants; but assessment of endodontically treated teeth adjacent to the proposed implant sites has seldom been reported. Assessment criteria are given for sound- and endodontically compromised teeth to ensure adequate preimplant preventive and restorative treatment and to minimize the chances of failure of dental implants adjacent to these teeth. Cases are used to illustrate pitfalls in the treatment planning process.

Clinical Protocols↗

Endodontic therapy associated with calcium hydroxide as an intracanal dressing: microbiologic evaluation by the checkerboard DNA-DNA hybridization technique.

This study evaluated the predominant microbiota of infected necrotic pulps and the effects of calcium hydroxide therapy on these microorganisms by the checkerboard DNA-DNA hybridization technique. Conventional endodontic therapy associated with calcium hydroxide as intracanal dressing was performed in 12 single-rooted teeth with pulp necrosis and periradicular bone lesion. Samples were collected from the canal at baseline and 14 days after therapy, and the presence of 44 bacterial species was determined by the checkerboard method. Significant differences in the microbiota from baseline to post-therapy were sought by the paired-samples t test. The most prevalent species included F. nucleatum ss. vincentii, C. sputigena, C. ochracea, S. constellatus, V. parvula, P. gingivalis, P. melaninogenica, and S. sanguis. Most of the microorganisms were reduced after treatment, particularly A. gerencseriae, A. israelii, A. naeslundii, C. gingivalis, C. ochracea, P. gingivalis, S. noxia, S. sanguis, and S. oralis (p < 0.05). Conversely, A. actinomycetemcomitans, C. sputigena, and E. corrodens increased in numbers after therapy. These results indicate that conventional endodontic therapy with calcium hydroxide results in the reduction of pathogenic species associated with pulp necrosis. However, its use is limited, because it did not eliminate the whole spectrum of microorganisms.

Adult↗

Effects of endodontic irrigation solutions on mineral content of root canal dentin using ICP-AES technique.

The aim of this in vitro study was to evaluate mineral content of root canal dentin after treatment with several endodontic irrigation solutions. Sixty mandibular anterior teeth extracted for periodontal reasons used. The crowns of the teeth were removed at the cemento-enamel junction. Pulp tissues were removed and the teeth were randomly divided into six groups including 10 teeth each. Root canals were enlarged with gates-glidden burs (# 1, 2, and 3). The groups were treated as follows: group 1, 0.2% chlorhexidine gluconate for 15 min; group 2, 3% H2O2 for 15 min; group 3, 17% EDTA for 15 min; group 4, 5.25% NaOCl for 15 min; group 5, 2.5% NaOCl for 15 min; and group 6, distilled water (control). Dentin chips were obtained using gates-glidden burs (# 4, 5, and 6). The levels of five elements calcium, phosphorus, magnesium, potassium, and sulfur in each specimens were analyzed using ICP-AES (Inductively Coupled Plasma Atomic Emission Spectrometry) technique. Changes in the levels of the chemical elements were recorded. The results were then statistically analyzed by one-way ANOVA and Tukey tests. There was a significant decrease in the calcium and phosphorus levels after treatment with all irrigation solutions except for 5.25% NaOCl when compared with the control group (p < 0.05). The K, Mg, and S level changes were not statistically significant (p > 0.05). It has been concluded that endodontic irrigation solutions have an effect on mineral contents of root dentin.

Analysis of Variance↗

The effect of antibiotics and endodontic antimicrobials on the polymerase chain reaction.

The effectiveness of endodontic antimicrobial treatment could be determined using sensitive molecular methods. The purpose of this study was to determine if antibiotics or endodontic reagents interfere with the ability of PCR to detect Enterococcus faecalis in vitro. Amoxicillin (25 mg/ml), clindamycin (15 mg/ml), tetracycline (25 mg/ml), doxycycline (10 mg/ml), calcium hydroxide, 1% buffered sodium hypochlorite (NaOCl1), 3% and 6% unbuffered NaOCl (NaOCl3 and NaOCl6), 2% chlorhexidine (CHX), 5% tincture iodine (TI), 2% iodine potassium iodide (IKI), chloroform (CF), 70% ethyl alcohol, 5% sodium thiosulphate, 5% citric acid or saline were added to 10 or 10 cells/ml E. faecalis ATCC 19433 for 1 h (1 wk for Ca(OH)2). Using PCR, all specimens were positive except for NaOCl3 and NaOCl6. PCR with Ca(OH)2 was positive with 10 cells/ml but negative with 10 cells/ml. The following reagents yielded negative culturing results: all antibiotics, Ca(OH)2, CHX, IKI, TI, NaOCl3, NaOCl6, and CF. BacLight nuclear staining revealed the presence of viable cells in all PCR positive, culture negative combinations, except for those with CF. Therefore, in the presence of threshold values of bacterial concentrations, all reagents tested except for NaOCl3 and NaOCl6 do not interfere with the detection of E. faecalis using PCR.

Animals↗

Searching for Archaea in infections of endodontic origin.

Archaea is a highly diverse group of prokaryotes, whose members have been traditionally recognized as extremophiles. Recently, some of these microorganisms have also been found to thrive in nonextreme environments, including the human body. Methanogenic archaea have been detected in samples from subgingival plaque associated with periodontal disease and a pathogenetic role is suspected. The purpose of this study was to survey samples taken from different types of endodontic infections for the presence of archaea. Samples were taken from untreated and treated root canals associated with asymptomatic chronic periradicular lesions as well as from cases diagnosed as acute periradicular abscesses. Overall, 96 samples were obtained. DNA from samples was extracted by using two different protocols and used as template for polymerase chain reaction amplification using oligonucleotide universal primers for the domains Archaea or Bacteria. Samples were also checked for the presence of spirochetes by making use of a group-specific primer. While bacteria were present in all samples, no case yielded archaeal DNA. Spirochetes occurred in a high number of cases. Our findings suggested that members of the Archaea domain are not members of the microbiota present in different types of endodontic infections and thereby may not be implicated in the etiology of apical periodontitis.

Archaea↗

The effect of human immunodeficiency virus on endodontic treatment outcome.

The purpose of this retrospective study was to compare periradicular healing between HIV positive and negative patients 1 yr after endodontic treatment of necrotic teeth with chronic apical periodontitis. The preoperative radiographs of 33 patients diagnosed with HIV and 33 medically healthy patients were scored by three endodontists using the Periapical Index (PAI) Scoring Method. Follow-up radiographs were taken 12 months after endodontic treatment and also scored with the PAI. The degree of healing, as determined by the mean PAI change, was compared between the two groups. There were no statistically significant differences between the two with respect to the degree of periradicular healing. In addition, the three evaluators were found to have very high inter-examiner agreement. The results indicate that clinicians do not have to alter their expectations for healing and resolution of periradicular lesions based solely on the HIV status of their patients.

Adolescent↗

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.

Adult↗

Endodontic implications of bisphosphonate-associated osteonecrosis of the jaws: a report of three cases.

Bisphosphonates are commonly used in medicine to maintain bone density in patients with certain nonneoplastic diseases or cancers. A serious adverse effect of bisphosphonates that has substantial dental significance is osteonecrosis that appears to uniquely affect the mandible and maxilla without occurring in other bones of the skeleton. Patients with bisphosphonate associated osteonecrosis of the jaws may present with pain and exposed necrotic bone. This has substantial clinical implications because surgical procedures (including extractions or endodontic surgical procedures) are contraindicated in the jaws of these patients and the presenting pain may mimic pain of odontogenic origin. This report describes three patients with bisphosphonate associated osteonecrosis and emphasizes the endodontic implications of managing these patients.

Aged↗