Quantitative And Qualitative Analysis Of Microorganisms In Root-filled Teeth With Persistent Infection: Monitoring Of The Endodontic Retreatment.

The aim of this study was to investigate in vivo microorganisms detected in root-filled teeth with post-treatment apical periodontitis and quantify colony-forming units (CFU) during endodontic retreatment. Fifteen root-filled teeth had their previous gutta-percha removed and were randomly instrumented before being divided into three groups and medicated with either [Ca(OH)2 + 2% CHX gel], [Ca(OH)2 + 0.9% NaCl] or 2% CHX gel. Samples were taken after removal of gutta-percha (S1), after chemomechanical preparation using 2% CHX gel (S2), and after inter-appointment dressing (S3) for 7 or 14 days later. Cultivable bacteria recovered from infected root canals at the three stages were counted and identified by means of culture and PCR assay (16S rDNA). Quantitative data were statistically analyzed by using Mann-Whitney test in which pairs of groups were compared (P < 0.05). CFU counts decreased significantly from S1 to S2 (P < 0.05). No significant difference was found between S2 and S3 (P = 0.3093) for all three experimental groups. Chemomechanical preparation and intra-canal dressing promoted significant median reductions of 99.61% and 99.57%, respectively, in the number of bacteria compared to S1 samples. A total of 110 cultivable isolates were recovered by culture technique from 32 different species and 7 different genera. Out of the 13 target species-specific primer of bacteria analyzed, 11 were detected during endodontic retreatment. The great majority of taxa found in post-treatment samples were Gram-positive bacteria, although Gram-negative bacteria were found by molecular methods. Moreover, our results showed that gutta-percha removal and chemomechanical preparation are effective for root canal disinfection, whereas additional intra-canal dressing did not improve disinfection.7302-

Evaluation of the biocompatibility of root canal sealers using subcutaneous implants

The purpose of this study was to evaluate in vivo the biocompatibility of Endométhasone, Pulp Canal Sealer EWT and AH-Plus root canal sealers after implantation in rat connective tissue. Twenty-four Wistar-Furth rats were used. Polyethylene tubes were filled with the sealers and implanted into specific dorsal subdermal tissue sites of the rats. Implants were removed after 3, 7 and 30 days, fixed and processed for glycol methacrylate-embedding technique to be examined microscopically. On the 3rd day, there was a mild inflammatory reaction to Pulp Canal Sealer EWT implants, but a severe response to the other sealers with presence of acute inflammatory cells. On the 7th day, tissue organization was more evident with attenuation of the inflammatory reaction, especially for the AH-Plus implants. On the 30th day, connective tissue with few inflammatory cells was observed in contact with all sealer implants. In this time interval, the tissue in contact with Pulp Canal Sealer EWT implants was more organized, while the tissue close to Endométhasone and AH-Plus implants showed a mild persistent inflammatory reaction and had similar results to each other. In conclusion, the sealers had a similar pattern of irritation, which was more severe in the beginning and milder with time, in such a way that all sealers showed a persistent mild reaction. Pulp Canal Sealer EWT yielded better tissue organization than Endométhasone and AH-Plus, which, in turn, showed similar results to each other

Jean-Marc Leveratto, Mary Leontsini, Internet et la sociabilité littéraire

Sur la quatrième de couverture de cet ouvrage que complète une courte « présentation » liminaire, Jean-Marc Leveratto et Mary Leontsini témoignent d’un double projet : d’une part, développer la recherche sociologique sur les pratiques de la lecture ; d’autre part, préciser la spécificité et la place du média internet dans le développement de la sociabilité littéraire. L’ambition de l’étude est donc d’abord épistémologique, car elle vise à observer avant tout la complexité des médiations et de..

Influence of the apical enlargement size on the endotoxin level reduction of dental root canals

Gram-negative bacteria play an essential role in endodontic infections because they have virulence factors such as endotoxin. Due to its potential cytotoxic activity, special attention has been given to the removal/neutralization of this endotoxin in the root canal system. OBJECTIVE: The aim of this study was to evaluate the influence of the apical enlargement size (AES) by using rotary instruments on the endotoxin level reduction of dental root canals. MATERIAL AND METHODS: Forty root canals of the mandibular premolar teeth were used. Escherichia coli endotoxin (055: B55) was inoculated into thirty root canals. Ten teeth served as the negative control group. After the incubation period, the first endotoxin samples were collected from the root canals with a sterile/apyrogenic paper point for the analysis of the endotoxin units (EU/mL) present before instrumentation (S1). Specimen instrumentation was performed with the Mtwo(®) rotary system in the sequence 10/.04, 15/.05, 20/.06, 25/.06, 30/.05, 35/.04 and 40/.04. To monitor the effectiveness of increasing apical enlargement on endotoxin removal, the second endotoxin samples were collected from all the root canals after instrumentation with the following instruments: #25/.06- (S2); #30/.05- (S3); # 35/.04- (S4); and #40/.04- (S5). Limulus amebocyte lysate (LAL) was used to quantify the levels of endotoxin. The results were statistically compared by using repeated measures of ANOVA with post hoc Tukey testing. RESULTS: Increasing levels of endotoxin removal was achieved by large sized apical enlargement: S2 (AES #25/.06)- 89.2%, S3 (AES #30/.05)- 95.9%, S4 (AES #35/.04)- 97.8% and S5 (AES #40/.04)- 98.2%. Substantial reduction of endotoxin content was obtained in S4 and S5 compared to S2 (p<0.05), however, the root canal preparation was not able to eliminate the endotoxin. CONCLUSIONS: Under the conditions of this study, it was concluded that the reduction of endotoxin levels of the dental root canals could be predicted by increasing the apical enlargement size

Comparative Study Of The Antimicrobial Efficacy Of Chlorhexidine Gel, Chlorhexidine Solution And Sodium Hypochlorite As Endodontic Irrigants.

The purpose of this study was to assess the in vitro the antimicrobial efficacy of chlorhexidine gluconate gel as an endodontic auxiliary chemical substance compared to sodium hypochlorite (NaOCl) and chlorhexidine gluconate solution. The antimicrobial efficacy of the tested substances was evaluated using the agar diffusion test. The growth inhibition zones produced by 0.2%, 1% and 2% chlorhexidine gel were evaluated against 5 facultative anaerobic bacteria and 4 pigmented Gram-negative anaerobes, and compared to the results obtained by NaOCl and chlorhexidine solution. The largest growth inhibition zones were produced when the test bacteria were in contact with 2% chlorhexidine gluconate gel (11.79 mm), being significantly different (p0.05) between the growth inhibition zones obtained with equal concentrations of chlorhexidine solution and gel. The results of this study indicate that, as far as its antimicrobial properties are concerned, chlorhexidine gel has a great potential to be used as an endodontic auxiliary chemical substance.18294-

Frequency of root resorption following trauma to permanent teeth

This retrospective study evaluated the frequency of development of root resorption in dental trauma cases involving supporting tissue. For 249 traumatized teeth of 125 patients aged between 7 and 51 years, we collected data on the gender and age of the patient, the teeth involved, the type of trauma, and the period between dental injury and initial examination. Radiographic parameters examined in relation to root resorption included the presence of inflammatory external root resorption, internal root resorption, replacement resorption, and canal calcification. Data were analyzed by chi-squared test, Fisher's exact test, and multiple logistic regression (P < 0.05). The results indicated that there was a significant relationship between the period from the date of injury until initial examination and the occurrence of inflammatory external resorption (P = 0.0199), as well as the type of injury (P = 0.0406). Furthermore, external resorption was most frequently associated with intrusive luxation (92.8%), followed by avulsion (89.0%), lateral luxation (80.2%), and extrusive luxation (77.4%). Among the types of dental injury, replacement resorption was observed more frequently in cases of avulsion (87.2%). The only factor that was significantly associated with this type of resorption was the type of injury (P < 0.0001). Root resorption is observed more frequently and its risk of development is higher in cases of severe trauma, especially avulsion and intrusive luxation572737

The Outcome Of Endodontic Treatment: A Retrospective Study Of 2000 Cases Performed By A Specialist.

The purpose of this study was to evaluate the treatment outcome of initial endodontic treatment and nonsurgical retreatment performed by an endodontic specialist in his private office. A total of 2,000 teeth were examined clinically and radiographically and the results were analyzed statistically by Pearson or Fisher's Exact test and multivariate logistic regression. The multivariate analysis evaluated joint associations among various factors, using logistic regression models. The dependent variable for this analysis was the dichotomous outcome: healed versus disease. The overall endodontic success rate was 91.45%, and the healed rate was significantly higher for initial endodontic treatments than for nonsurgical retreatments; teeth without lesion than for those with lesions; teeth treated without complications than for those with complications; recall period of 18-24 months than for other periods, and teeth with final coronal restoration than for those without. Of the 1376 teeth treated in the initial endodontic treatment sample, the success rate was 94.0%. Multivariate analysis identified the presence of procedural complications (file breakage, perforation and flare-up), as well as the absence of the restorations at follow-ups as the significant predictors of outcome, showing lower rates of success. Of the 624 teeth in the nonsurgical retreatment sample, 85.9% were successful. Stepwise logistic regression analysis revealed that preoperative radiolucency was a strong statistically significant factor to determine lower rates of success than in its absence. Two additional variables (age and tooth type) were found to have a significant influence on the outcome of the retreatment sample. A higher healed rate was observed for the 50-59 years age groups than others, while multirooted (molars) teeth revealed a significantly lower percentage of success than pre-molars and anterior teeth.331278-8