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At least 1,549 records · Page 86Linked to original sources
PubMed2005

Anatomic Endodontic Technology (AET)--a crown-down root canal preparation technique: basic concepts, operative procedure and instruments.

AIM: To illustrate the conceptual basis and the operative procedure of the Anatomic Endodontic Technology (AET) technique and to illustrate the specific instruments used in each phase. SUMMARY: The basic characteristics of the AET technique are reported. The instruments and procedure are described in three phases: coronal access, coronal-middle preparation and apical preparation. In the first phase, correct cavity design is described. In the coronal-middle phase, the use of four stainless steel shaping instruments, powered by a reciprocating handpiece is described, incorporating a brushing-milling action against canal walls. During the apical phase, dedicated apical stainless steel and NiTi hand instruments are used to complete the preparation. The stainless steel apical files are used with a 1/4 turn and withdrawal movement whilst the NiTi are used in 360 degrees rotary motion. KEY LEARNING POINTS: Most current canal shaping techniques do not prepare all the canal walls and can result in over-enlargement in some areas. AET defines three regions of the canal: coronal (from the cavo-surface of the access cavity), coronal-middle, and apical. Coronal-middle instrumentation is undertaken with four mechanically driven stainless steel shaping instrument used in brushing-milling action against canal walls. Apical preparation is completed by hand and with the formation of a stop.

Dental Alloys↗
PubMed2005

Presence of pores and vacuoles in set endodontic sealers.

AIM: To assess qualitatively the presence of pores and vacuoles in the structure of various endodontic sealers when set. METHODOLOGY: Eight specimens were prepared in keeping with Instituto Argentino de Racionalización de Materiales (IRAM) and ISO regulations for each of the 10 sealers assessed. Four specimens per sealer were examined to identify the presence of structural defects, termed pores, on the external surface. The remaining four specimens were used to examine the presence of defects on the surface exposed by cross-sectional fracture; these were termed vacuoles. The largest and smallest diameters of the pores and vacuoles were measured by scanning electron microscope on both surfaces. The structural defects were classified according to their frequency as abundant, frequent, scarce or exceptional. RESULTS: Pores and vacuoles were consistently found in every specimen of each sealer. However, their frequency and dimensions were greater in zinc-eugenol-based sealers than in epoxy-resins and glass-ionomer sealers; they increased if the sealer contained calcium hydroxide. The diameter of the pores ranged from 5 to 320 microm and the diameter of the vacuoles ranged from 80 to 500 microm. The diameter of the vacuoles always exceeded that of the pores. CONCLUSIONS: Pores and vacuoles were a consistent finding in set sealers. Their frequency and size depended on the density of the sealer and increased when the sealers contained calcium hydroxide.

Bismuth↗
PubMed2006

Prostaglandin E production and viability of cells cultured in contact with freshly mixed endodontic materials.

AIM: To determine whether commonly used endodontic sealers could either induce or increase the release of prostaglandin E2 (PGE2) when in contact with cell types found in the periapical tissues. METHODOLOGY: Freshly mixed samples of Roth 801 sealer, Sealapex and ProRoot mineral trioxide aggregate (MTA) were placed in contact with cultured macrophages and fibroblasts for 24 h. The supernatant from the cultures was assayed for PGE2 using enzyme-linked immunosorbent assay. Cell viability counts were made. As a positive control, similar cultures were also exposed to lipopolysaccharide and the supernatant analysed for PGE2. Data were compared by anova. RESULTS: The three materials examined in these experiments did not stimulate increased PGE2 release from either of the cell lines. In control cultures, lipopolysaccharide increased PGE2 release from macrophages but not from fibroblasts. Viability counts revealed that, whilst Roth 801 sealer caused some cell death in both fibroblasts and macrophages, Sealapex led to cell death only in the macrophage cultures. ProRoot MTA did not lead to statistically significant cell death in either culture. CONCLUSIONS: Under 24-h culture conditions, the three freshly mixed test materials did not increase directly either production or release of PGE2 from either macrophages or gingival fibroblasts. Roth 801 decreased cell viability counts for both fibroblasts and macrophages. Sealapex decreases macrophage viability. ProRoot MTA did not affect viability in either cell line.

Aluminum Compounds↗
PubMed2006

Reducing fear of pain associated with endodontic therapy.

AIM: To provide subjects with positive information about endodontic treatment (ET) to reduce fear of pain associated with ET. METHODOLOGY: A large sample (n = 437) was randomly allocated to read one of five informative paragraphs and afterwards asked to complete two questionnaires (dental anxiety and fear of dental pain). The paragraphs consisted of dental information obtained from patient brochures. One (experimental) paragraph consisted of positive information about pain during ET. Analysis of variance followed by post hoc analysis was used to detect differences in mean score. RESULTS: Subjects who were given the positive information regarding ET indicated they were less fearful of pain associated with ET. CONCLUSIONS: The clinical implication of this experiment is that patients should be accurately informed about pain associated with ET. In this way, the patient may be more at ease before and during treatment, decrease avoidance behaviour and make decisions regarding treatment choice, based on common sense rather than fearful expectations.

Adult↗
PubMed2006

Endodontics and infective endocarditis--is antimicrobial chemoprophylaxis required?

The purpose of this review is to evaluate the evidence implicating nonsurgical endodontic procedures in inducing infective endocarditis (IE). The literature is reviewed and findings about dental procedures that elicit bacteraemia [in particular root canal treatment (RCT)], sequelae of bacteraemia, relationship between IE and RCT and variation between antibiotic prophylaxis (AP) guidelines are highlighted. At present, there is still significant debate as to which dental procedures require chemoprophylaxis and what antibiotic regimen should be prescribed. Currently, there are insufficient primary data to know whether AP is effective or ineffective against IE. Practitioners are bound by current guidelines and medico-legal considerations. Thus, the profession requires clear, uniform guidelines that are evidence-based.

Amoxicillin↗
PubMed2006

Endodontic status amongst 35-year-old Oslo citizens and changes over a 30-year period.

AIM: To determine the prevalence of apical periodontitis and quality of root fillings in 35-year-old citizens of Oslo, Norway in 2003, and to compare the results with data from the same age cohort collected by repetitive cross-sectional studies in 1973, 1984 and 1993. METHODOLOGY: A random sample of 250 35-year-old Oslo inhabitants was drawn from The National Bureau of Statistics Recordings. Attendance rate was 64%. Root filled teeth and teeth with periapical pathology were detected from panoramic radiographs and additional periapical radiographs of affected teeth were processed. The preriapical status was evaluated by applying the periapical index system (PAI). Chi-square and Student's t-tests were used for the evaluation of differences between the groups. RESULTS: Twenty-three per cent of the individuals examined had root filled teeth and 16% had at least one tooth with apical periodontitis. Root filled teeth were associated with PAI values of 1 and 2 (health) in 57% of cases. Prevalence of root filled teeth and apical periodontitis remained unchanged during the past 10 years. An increase in the proportion of root filled teeth with apical periodontitis from 18% in 1973 to 43% in 2003 was observed. CONCLUSIONS: Despite continuous improvement in dental health (reduced DMF-values) compared with the previous Oslo studies; there was no improvement in endodontic status from 1993 to 2003.

Adult↗
PubMed2007

The corrosion of nickel-titanium rotary endodontic instruments in sodium hypochlorite.

AIM: To evaluate the corrosion resistance of nickel-titanium (NiTi) endodontic rotary instruments immersed in 5.25% sodium hypochlorite (NaOCl) solution. METHODOLOGY: The corrosion performance of NiTi instruments (S1 25 mm, ProTaper Dentsplay Maillefer, Ballaigues, Switzerland) was evaluated using commercial 5.25% NaOCl solution (pH = 12.3), and the same solution partially neutralized adding H2SO4 to reach pH = 10.1. Electrochemical measurements were carried out using a potentiostat equipped with a five-channel zero resistance ammeter (ZRA) for galvanic current measurements. The instruments were sectioned into three parts (cutting part, noncutting part and shank) and degreased with acetone and rinsing with demineralized water prior to being immersed in NaOCl solution for testing. Each set of the three parts constituted one 'virtual' instrument through the ZRA, giving access to the galvanic currents that circulate between the three parts. Nine instruments were employed to check the reproducibility of the electrochemical measurements. RESULTS: The corrosion potential (E(corr)) of the NiTi alloy reached the passive domain in approximately 20 s of immersion in the solution having a pH 10.1. After this initial period the potential remained steady, indicating that stable passivation was achieved. However, at pH 12.3 no stationary state was achieved even after 6000 s of immersion time. Thus, the alloy was not stable in this medium from a corrosion point of view. CONCLUSIONS: The corrosion resistance of NiTi alloy was enhanced by lowering the pH of NaOCl solution to 10.1, which allows the system to reach the stability domain of the passivating species TiO2 and NiO2.

Corrosion↗
PubMed2007

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

AIM: 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. SUMMARY: 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. KEY LEARNING POINTS: 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.

Adolescent↗
PubMed2004

Treponema species associated with abscesses of endodontic origin.

Spirochetes have been frequently observed in abscesses of endodontic origin, but they have rarely been identified. This study sought to investigate the prevalence of eight oral treponemes in acute periradicular abscesses using a species-specific nested polymerase chain reaction assay. Purulent exudate was collected by aspiration from 19 cases diagnosed as acute periradicular abscesses and 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 the 16S rDNA of each Treponema species. The species-specific nPCR assay used in this study allowed the detection of Treponema denticola in 79%(15 of 19), Treponema socranskii in 26%(5 of 19), Treponema pectinovorum in 21% (4 of 19), Treponema amylovorum in 16% (3 of 19), and Treponema medium in 5% (1 of 19) of the cases. Spirochetal DNA was found in 89% of the cases (17 of 19). The number of Treponema species per case ranged from 1 to 3 (mean, 1.5). Treponema vincentii, Treponema lecithinolyticum and Treponema maltophilum were not detected in any pus sample. The present data lend support to the assertion that Treponema species, particularly T. denticola and T. socranskii, may be involved in the pathogenesis of acute periradicular abscesses.

Adolescent↗
PubMed2006

Resistance to acidic and alkaline environments in the endodontic pathogen Enterococcus faecalis.

BACKGROUND/AIMS: This study aimed to investigate the biochemical mechanisms employed by the endodontic pathogen Enterococcus faecalis to confer acid- and alkali-resistance and to compare these with the mechanisms of representative oral streptococci. METHODS: E. faecalis JCM8728, Streptococcus mutans NCTC10449 and Streptococcus sanguinis ATCC10556 were used to assess both acid- and alkali-resistance by examining: (i) growth in complex media; (ii) stability of intracellular pH (pH(in)); (iii) cell durability to leakage of preloaded BCECF (2',7'-bis-(2-carboxyethyl)-5,6-carboxy-fluorescein); and (iv) cell permeability to SYTOX-Green. RESULTS: Growth was initiated by E. faecalis at pH 4.0-11.0, by S. mutans at pH 4.0-9.0 and by S. sanguinis at pH 5.0-9.0. The pH(in) was similar to the extracellular pH in S. mutans and S. sanguinis at pH 5-10, while the pH(in) of E. faecalis was maintained at approximately 7.5-8.5 when extracellular pH was 7.5-10 and was maintained at levels equivalent to the extracellular pH when pH < 7.5. Cell membranes of E. faecalis were resistant to BCECF leakage when extracellular pH was 2.5-12 and to SYTOX-Green permeability at pH 4-10. The cell membrane durability to extracellular pH in E. faecalis was higher than that observed in the Streptococcus strains. CONCLUSION: Compared to S. mutans, E. faecalis was found to be equally resistant to acid and more resistant to alkalis. The results suggest that pH-resistance in E. faecalis is attributed to membrane durability against acid and alkali, in addition to cell membrane-bound proton-transport systems. These characteristics may account for why E. faecalis is frequently isolated from acidic caries lesions and from persistently infected root canals where calcium hydroxide medication is ineffective.

Acids↗
PubMedDate not supplied

Effect of core diameter and surface treatment on the retention of resin composite cores to prefabricated endodontic posts.

PURPOSE: With advances in adhesive dentistry and current emphasis on esthetic restorations, dowel systems have been developed to take advantage of these new techniques. Of interest when using these systems is the interaction between core materials and post materials. This investigation compared the tensile retentive force of two resin composite core materials to two metallic and one non-metallic prefabricated endodontic posts. Two dimensions of core build-up and two post-surface treatments were tested. MATERIALS AND METHODS: One hundred twenty posts (stainless steel, titanium alloy, and glass fiber-impregnated resin) were secured in a jig with 4 mm of the post extending into a cylindrical matrix. The matrix formed cylinders with diameters of 3 and 5 mm into which resin composite was inserted. The posts were treated or not treated with a bonding agent. After storage for 24 hours at 100% humidity, five specimens per condition were tested in an Instron testing machine at a crosshead speed of 0.5 mm/min. Failure loads were recorded in kilograms and failure modes were observed under light microscopy (40 x). Four-way analysis of variance and multiple comparison testing were used to compare means at the 0.05 level of significance. RESULTS: The means and standard deviations of tensile loads were calculated. All variables were significant in either main effects or interactions ( p<0.05). Fisher's PLSD intervals for post, core, treatment, and diameter were 2.0, 1.6, 1.6, and 1.6 kg, respectively. In most cases, the retentive force recorded for metallic posts was higher than that of glass fiber posts. Titanium posts had higher retentive forces than did the stainless steel posts. For metallic posts, 5-mm cores provided higher forces than 3-mm cores. In the glass fiber group, core diameter was not significant. For core materials, Build-It gave higher results with stainless steel posts, and FluoroCore gave higher results with the titanium ones. The surface treatment results were mixed. In the metallic post groups the adhesive failure data ranged between 80% and 100%, whereas in the glass fiber post groups, adhesive failures ranged between 60% and 70%. CONCLUSIONS: Within the limitations of this study, the metallic post groups always provided higher tensile retentive forces, with the titanium post groups showing higher retentive forces than the stainless steel ones. In the glass fiber post groups, different core diameters did not affect retention values.

Analysis of Variance↗
PubMed1985

Influence of antiseptic storage solutions on physical properties of endodontic guttapercha points.

The effect of three commonly used antiseptic storage solutions on some physical properties of endodontic guttapercha points was studied. The solutions tested were: 70% isopropyl alcohol, 5% chloramine and 0.5% chlorhexidine. As a control solution, physiologic saline was used. There was a marked decrease in the force necessary to bend the points after 1 month. With few exceptions, the greatest decrease was seen with solutions containing alcohol, i.e. chlorhexidine and isopropyl alcohol. The difference between aqueous and alcoholic storage solutions was also noted for linear dimensional changes. Physiologic saline and chloramine hardly affected the length of the points. The decrease in stiffness may add to the difficulties when handling guttapercha points of small dimensions in curved root canals. From this point of view it is therefore recommended to avoid storage of points in antibacterial solutions. Rather, an effective surface disinfecting of the points immediately prior to use would be desirable.

1-Propanol↗
PubMed1996

Characterization of new periodontal and endodontic isolates of spirochetes.

Gas chromatographic analysis of cellular fatty acids (CFA), biochemical reactions, electrophoresis of soluble cellular proteins, as well as immunodiffusion were used to discriminate between 16 fresh spirochete isolates from periodontal and endodontic infections. CFA patterns were compared by the Hewlett Packard MIDI library to all available reference strains, and results of the biochemical tests were compared to VPI's records for treponemal strains. The electrophoretograms of soluble proteins of the fresh isolates were compared to those of previously well described strains of Treponema denticola, T. pectinovorum, T. vincentii, T. socranskii subsp. socranskii, T. socranskii subsp. paredis, T. socranskii subsp. buccale, and T. socranskii 04. Immunodiffusion was carried out by using adsorbed polyclonal rabbit antibodies to representative strains of the species mentioned. These methods separated most clinical strains from approved species strains, suggesting that new species had been isolated.

Bacterial Proteins↗
PubMed2004

Cytotoxicity and sealing properties of four classes of endodontic sealers evaluated by succinic dehydrogenase activity and confocal laser scanning microscopy.

The objectives of this study were to evaluate the cytotoxicity and sealing properties of four classes of endodontic sealers (PCS/Kerr, RoekoSeal/Roeko, TopSeal/Dentsply, and EndoREZ/Ultradent). For cytotoxicity testing (MTT method), the materials were either placed immediately in contact with cultured cells or 24 h after setting, then evaluated at three subsequent time points (24 h, 48 h, or 1 wk). For the leakage study, extracted human roots were obturated with acrylic cones and sealers and immersed for 48 h into rhodamine-labeled lipopolysaccharide. The roots were then observed under a confocal laser scanning microscope to estimate (semiquantitatively) the presence of the rhodamine-lipopolysaccharide (LPS) inside the canal. The results showed that cytotoxicity generally increased with time, and that most materials pose significant cytotoxic risks, particularly in the freshly mixed condition. Further, all materials showed significant leakage although there was large variation among teeth. Overall, the silicon-based material (Roeko Seal) was less cytotoxic and more effective in sealing root canals against LPS leakage than other materials.

Analysis of Variance↗
PubMed2004

A multivariate analysis of the outcome of endodontic treatment.

In the present study, multivariate analyses were performed on clinical and treatment variables that may influence the outcome of endodontic treatment. Data collected in a previous clinical-radiographic follow-up study were used. Of 810 treated, 675 roots in 498 teeth were followed for 6 months to 4 yr. Of these, 192 (the CAP group) had pre-existing, chronic apical periodontitis and 483 (the NAP group) had not. Root canal treatment followed a standard procedure with one of three sealers chosen at random. Demographic, clinical and radiographic variables were recorded at the start of, and during treatment. The periapical index (PAI) score was used to record the outcome of treatment, and applied in two different endpoint modes (END1 and END2) as the dependent variable for multivariate statistical analyses using logistic regression and the general model. The modes reflected increasing PAI scores (END1) and conventional success/failure assessment (END2). Dropouts were largely similar to the cases followed up. A total of 10 preoperative and peroperative variables were found to be significantly associated with treatment outcome by the multivariate analyses of either the total material or the NAP or CAP subgroups. Several of these were not significant in univariate analyses (e.g. the effect of sealer). Conventional success/failure analyses (END2) identified fewer of the influential variables and had low explanatory power, whereas PAI scores on an ordinal scale (END1) were most sensitive in identifying variables of influence on the treatment outcome.

Adolescent↗
PubMed2004

Apical periodontitis development and bacterial response to endodontic treatment. Experimental root canal infections in monkeys with selected bacterial strains.

In six monkeys, 160 root canals were inoculated with a combination of four bacterial strains belonging to species Streptococcus milleri, Peptostreptococcus anaerobius, Prevotella oralis, and Fusobacterium nucleatum. In two other monkeys, 24 root canals were inoculated with a five-strain combination consisting of these strains and a strain of Enterococcus faecalis. All strains were previously isolated from an infected monkey root canal. After 8-12 months, survival of the strains was recorded bacteriologically, and the reaction in the periapical region was radiographed. From 180 of 184 root canals, one or more of the bacterial strains were reisolated. The two facultative strains were more frequently reisolated than the anaerobic strains. Apical periodontitis was registered in the periapical region of more than 96% of root canals with reisolated bacteria but in none of those without reisolated bacteria. Endodontic treatment was carried out in two sessions with an interval of 14 d without interappointment dressings, and the effect was evaluated bacteriologically before and after each treatment. The chemo-mechanical treatment reduced significantly the number of strains and bacterial cells. The facultative bacteria were more resistant to the treatment than the anaerobic bacteria. The five-strain combination had a higher survival rate than the four-strain combination.

Animals↗
PubMed1989

Endodontic effects of root planing in humans.

Although the deliberate removal of cementum by root planing remains part of periodontal therapy, its scientific basis is under challenge. A potentially harmful effect of root planing is the exposure of dentinal tubules to the oral environment; this study investigated the short-term endodontic effects of root planing in humans. Ten teeth with significant loss of periodontal attachment had one proximal surface root planed; the other proximal surface was not root planed. After 10-14 days, the teeth were extracted and processed for light microscopic and SEM examination. Hypersensitivity to thermal stimuli was reported by 4 subjects after root planing. Chronic pulpitis was found in 3 pulps adjacent to the area of root planing. Bacterial penetration of dentin was observed, although the depth of penetration was less than reported by others. The results indicated that previous perceptions of the beneficial role of root planing in periodontal therapy require reconsideration.

Dental Prophylaxis↗