Antimicrobial action of intracanal medicaments on the external root surface.

OBJECTIVES: To assess in vitro the antimicrobial action of intracanal medicaments in the external root surface, with or without of cementum. METHODS: After the placement of intracanal medicaments, the coronal and apical openings were sealed. The antimicrobial action of 2% chlorhexidine gel (2%CHX); calcium hydroxide+2% chlorhexidine gel (CH+2%CHX); calcium hydroxide+2% chlorhexidine gel+zinc oxide (CH+2%CHX+ZnO); calcium hydroxide+saline solution (CH+SS) was evaluated against Enterococcus faecalis, Candida albicans, Actinomyces viscosus and Porphyromonas gingivalis. The samples were placed over the agar, and the zones of inhibition of microbial growth were measured after the incubation period. RESULTS: The antimicrobial effects of the medicaments could be ranked from strongest to weakest as follows: 2%CHX, CH+2%CHX, CH+2%CHX+ZnO, CH+SS. No differences among groups were verified in the presence or absence of cementum. CONCLUSIONS: 2%CHX containing medicaments diffused into the dentin and reached the outer surface, exerting antimicrobial action.

Polymerase chain reaction of Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia in primary endodontic infections.

The aim of this study was to investigate the correlation between endodontic clinical signs and symptoms and the presence of Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia or their association by nested polymerase chain reaction assay. Microbial samples were taken from 50 cases with necrotic pulp tissues in primary infections. DNA was extracted from the samples, which were analyzed for the presence of three endodontic pathogens by using species-specific primers. P gingivalis, T denticola, and T forsythia were detected in 46%, 38%, and 22% of the symptomatic cases, respectively. The bacterial complex composed by T forsythia, P gingivalis, and T denticola was found in 14% of the cases with spontaneous pain, tenderness to percussion, swelling, and pain on palpation. The high prevalence of P gingivalis, T denticola, and T forsythia in the samples examined suggests that these bacteria are related to the etiology of symptomatic periradicular diseases.

Residual effects and surface alterations in disinfected gutta-percha and Resilon cones.

The aim of this study was to evaluate alterations on the surface of gutta-percha and Resilon cones when exposed to 2% chlorhexidine gel (CHX) and 5.25% sodium hypochlorite (NaOCl) and to evaluate their possible antibacterial residual effects against Enterococcus faecalis and Porphyromonas gingivalis. A total of 270 medium tapered cones (135 gutta-percha and 135 Resilon) were selected and divided into three groups, according to the substance (NaOCl, CHX, and sterile saline solution). The cones were immersed in each substance (for 1, 5, 10, 20, and 30 min), rinsed in saline solution, and dried. They were placed onto inoculated agar plates and incubated under specific conditions. Scanning electron microscopy analysis was performed on additional 270 disinfected cones. Another 18 cones were used as controls. Based on the results, it was concluded that Resilon cones exposed to CHX for 10, 20, and 30 min demonstrated residual antibacterial action and that substances did not cause alterations to the cones' surface.

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.

Molecular analysis of Filifactor alocis, Tannerella forsythia, and treponema denticola associated with primary endodontic infections and failed endodontic treatment.

The aim of this study was to investigate the presence of strict anaerobes such as Filifactor alocis, Tannerella forsythia, and Treponema denticola in primary and secondary root-infected canals with periapical lesions by molecular analysis and the association of these species with specific endodontic signs and symptoms. Microbial samples were taken from 100 root canals, 50 with necrotic pulp tissues (NPT, primary infection), and 50 with failed endodontic treatment (FET, secondary infection). DNA was extracted from the samples, which were analyzed for the presence of three endodontic pathogens using species-specific primers and PCR. F. alocis were isolated from 23 canals with NPT and 12 canals with FET; T. forsythia from 12 canals with NPT and three canals with FET; T. denticola from 19 canals with NPT and 12 canals with TEP. Suggested associations were found between primary infection and the presence of F. alocis and T. forsythia (both p < 0.05). In particular, associations were found between: pain and F. alocis; swelling and F. alocis; tenderness to percussion and T. forsythia; mobility and T. forsythia and T. denticola; wet canals and F. alocis, T. forsythia, and T. denticola; purulent exsudate and F. alocis, T. forsythia and T. denticola; abscess and F. alocis, T. forsythia, and T. denticola (all p < 0.05). The findings of this study indicated that F. alocis, T. forsythia, and T. denticola seem to be associated with endodontic signs and symptoms. Additionally, F. alocis and T. forsythia were detected more frequently in teeth with necrotic pulp than in teeth with failing endodontic treatment.

Quantification of endotoxins in necrotic root canals from symptomatic and asymptomatic teeth.

The purpose of this investigation was to quantify the concentration of endotoxin in necrotic root canals and investigate the possible relationship between the concentration of endotoxin and endodontic signs and symptoms. Samples were collected from root canals of 50 patients requiring endodontic treatment due to necrosis of the pulpal tissue. Anaerobic techniques were used to determine the number of c.f.u. in each sample. A quantitative chromogenic Limulus amoebocyte lysate assay was used to measure the concentration of endotoxin in each sample. The presence of c.f.u. was detected by culture in all samples (range 10(2)-5x10(6)). In samples from cases of patients with spontaneous pain, the mean c.f.u. was 1.43x10(6) while in asymptomatic cases it was 9.1x10(4). Endotoxin was present in all the samples studied [range 2390.0-22100.0 endotoxin units (EU) ml-1]. The mean concentration of endotoxin in samples from patients with spontaneous pain was 18540.0 EU ml-1 while in asymptomatic cases it was 12030.0 EU ml-1. Asymptomatic cases generally had lower levels of endotoxin (i.e. a negative association). A positive association was found between endotoxin and symptomatic cases (e.g. spontaneous pain, tenderness to percussion, pain on palpation, swelling and purulent exudates). This study showed that endotoxin is present in high concentrations in root canals of symptomatic teeth. There was a positive correlation between the concentration of endotoxin in the root canal and the presence of endodontic signs and symptoms.

Evaluation of endodontic treatments performed by students in a Brazilian Dental School.

The aims of this study were to evaluate the clinical outcomes of root canal treatments performed by final-year students in the Dental School of Piracicaba, State University of Campinas, SP, Brazil, during the year 2000 and to evaluate the success rate of these treatments at follow-ups conducted one and three years later (2001-03). All 579 endodontic treatments performed by final-year students were selected for this investigation. Detailed personal and dental history was obtained from the patient's records. Clinical and radiographic follow-up examinations were performed. For 78.8 percent of the cases, dental caries was recorded as the cause for performing endodontic treatment; for 8.8 percent, prosthetic reasons were given; and for 12.4 percent, failure of the endodontic treatment was the reason. The largest percentage (30.7 percent) of recalled patients was examined after one year; the success rate at this follow-up evaluation ranged from 83 percent to 96 percent depending on the pulp status prior to the root canal treatment. After three years, only 8 percent of treated patients returned; assessment for them revealed a 75.5 percent success rate. Dental caries is still the main reason for endodontic treatment. This level of success of the root canal treatment in a Brazilian dental school is similar to other reports in the literature.

Microbial evaluation of traumatized teeth treated with triple antibiotic paste or calcium hydroxide with 2% chlorhexidine gel in pulp revascularization.

INTRODUCTION: Revascularization outcome depends on microbial elimination because apical repair will not happen in the presence of infected tissues. This study evaluated the microbial composition of traumatized immature teeth and assessed their reduction during different stages of the revascularization procedures performed with 2 intracanal medicaments. METHODS: Fifteen patients (7-17 years old) with immature teeth were submitted to the revascularization procedures; they were divided into 2 groups according to the intracanal medicament used: TAP group (n = 7), medicated with a triple antibiotic paste, and CHP group (n = 8), dressed with calcium hydroxide + 2% chlorhexidine gel. Samples were taken before any treatment (S1), after irrigation with 6% NaOCl (S2), after irrigation with 2% chlorhexidine (S3), after intracanal dressing (S4), and after 17% EDTA irrigation (S5). Cultivable bacteria recovered from the 5 stages were counted and identified by means of polymerase chain reaction assay (16S rRNA). RESULTS: Both groups had colony-forming unit counts significantly reduced after S2 (P < .05); however, no significant difference was found between the irrigants (S2 and S3, P = .99). No difference in bacteria counts was found between the intracanal medicaments used (P = .95). The most prevalent bacteria detected were Actinomyces naeslundii (66.67%), followed by Porphyromonas endodontalis, Parvimonas micra, and Fusobacterium nucleatum, which were detected in 33.34% of the root canals. An average of 2.13 species per canal was found, and no statistical correlation was observed between bacterial species and clinical/radiographic features. CONCLUSIONS: The microbial profile of infected immature teeth is similar to that of primarily infected permanent teeth. The greatest bacterial reduction was promoted by the irrigation solutions. The revascularization protocols that used the tested intracanal medicaments were efficient in reducing viable bacteria in necrotic immature teeth.

Chlorhexidine in endodontics.

Chemical auxiliary substances (CAS) are essential for a successful disinfection and cleanness of the root canals, being used during the instrumentation and if necessary, as antimicrobial intracanal medicaments. Different CAS have been proposed and used, among which sodium hypochlorite (NaOCl), chlorhexidine (CHX), 17% EDTA, citric acid, MTAD and 37% phosphoric acid solution. CHX has been used in Endodontics as an irrigating substance or intracanal medicament, as it possesses a wide range of antimicrobial activity, substantivity (residual antimicrobial activity), lower cytotoxicity than NaOCl whilst demonstrating efficient clinical performance, lubricating properties, rheological action (present in the gel presentation, keeping the debris in suspension); it inhibits metalloproteinase, is chemically stable, does not stain cloths, it is odorless, water soluble, among other properties. CHX has been recommended as an alternative to NaOCl, especially in cases of open apex, root resorption, foramen enlargement and root perforation, due to its biocompatibility, or in cases of allergy related to bleaching solutions. The aim of this paper is to review CHX's general use in the medical field and in dentistry; its chemical structure, presentation form and storage; mechanism of action; antimicrobial activity including substantivity, effects on biofilms and endotoxins, effects on coronal and apical microbial microleakage; tissue dissolution ability; interaction with endodontic irrigants; effects on dentin bonding, metalloproteinases and collagen fibrils; its use as intracanal medicament and diffusion into the dentinal tubules; its use as disinfectant agent of obturation cones; other uses in the endodontic therapy; and possible adverse effects, cytotoxicity and genotoxicity.

Comparison of endotoxin levels in previous studies on primary endodontic infections.

BACKGROUND: This study was performed to determine which of the quantitative methods, namely, chromogenic endpoint, chromogenic kinetic, and turbidimetric kinetic ones, best fit for the analysis of primary endodontic infections. METHODS: Twenty-one root canals with apical periodontitis were sampled with paper points. The same sample was analyzed by means of the endpoint chromogenic Limulus amebocyte lysate (LAL) assay (QCL), quantitative kinetic chromogenic LAL assay (KQCL), and kinetic turbidimetric LAL assay (Turbidimetric). RESULTS: All three LAL methods were effective in the recovery of endotoxin from root canal infection. Regardless of the method tested, endotoxin was detected in 100% of the root canals (21/21). The KQCL assay yielded a median value of endotoxin of 7.49 EU/mL, close to and not significantly different from those for the turbidimetric test (9.19 EU/mL) (both kinetic methods) (p > 0.05). In contrast, the endpoint QCL showed a median value of 34.20 EU/mL (p < 0.05). The comparison of the three methods revealed that both turbidimetric and KQCL methods were more precise, with best reproducibility (the coefficient variation between analysis of the root canal and its duplicate was lower than 10%). The inhibition/enhancement assay indicated a good interaction between the root canal samples with the turbidimetric method. CONCLUSION: This study has revealed that quantitative kinetic-turbidimetric and kinetic-chromogenic LAL methods are best fitted for the analysis of endotoxins in root canal infection, both being more precise and allowing better reproducibility compared with the endpoint-QCL assay.

Clinical investigation of the efficacy of chemomechanical preparation with rotary nickel-titanium files for removal of endotoxin from primarily infected root canals.

INTRODUCTION: This clinical study was conducted to investigate the ability of chemomechanical preparation with 2.5% NaOCl + 17% ethylenediaminetetraacetic acid (EDTA) and rotary nickel-titanium (NiTi) system in removing endotoxin from primary root canal infection with apical periodontitis. METHODS: Twenty-one root canals with necrotic pulps were selected. Samples were collected before (s1) and after chemomechanical preparation (s2). The limulus amebocyte lysate (LAL) assay was used to quantify endotoxins. RESULTS: The LAL assay indicated that endotoxins were present in 100% of the root canals investigated (19/19) before (s1) and after chemomechanical preparation (s2). Analyses of the quantitative data revealed that the endotoxin content was significantly reduced at s2 (98.06%) compared with that at s1 (P < .05). CONCLUSIONS: Our findings indicate that chemomechanical preparation with 2.5% NaOCl + 17% EDTA and rotary NiTi files was effective in reducing endotoxin load in the root canal infection from primarily infected teeth with apical periodontitis.

Microbial analysis of canals of root-filled teeth with periapical lesions using polymerase chain reaction.

The objective of the present study was to investigate the presence of nine bacterial species in root-filled teeth associated with periapical lesions using a polymerase chain reaction analysis and to correlate these species with clinical features of the cases. DNA was extracted from 45 canal samples of root-filled teeth with periapical lesions. A PCR assay using species-specific primers of 16S rDNA and the downstream intergenic spacer region was used for microbial detection. Enterococcus faecalis was the most prevalent species, detected in 77.8% of the study teeth, followed by Peptostreptococcus micros, detected in 51.1%. Porphyromonas gingivalis, Porphyromonas endodontalis, Prevotella intermedia, and Prevotella nigrescens were detected in 35.6%, 22.2%, 11.1%, and 11.1% of the sampled teeth, respectively. Moreover, PCR detected Filifactor alocis in 26.7%, Treponema denticola in 24.4%, and Tannerella forsythia in 4.4% of the samples. T. denticola and P. micros were statistically associated with tenderness to percussion (p < 0.05). P. nigrescens was associated with the presence of spontaneous pain and abscess (p < 0.05). P. endodontalis and P. nigrescens were associated with purulent exudates (p < 0.05). Synergistic relationship was also observed between some species. The results of this study indicated that E. faecalis was the most frequently identified test species by PCR in teeth with failing endodontic treatment.

Gemella morbillorum in primary and secondary/persistent endodontic infections.

OBJECTIVE: To investigate the presence of Gemella morbillorum by culture or nested PCR in primary and secondary/persistent endodontic infections. STUDY DESIGN: Microbial samples were taken from 50 cases with primary and 50 cases with secondary/persistent endodontic infections. Microbiologic techniques were used for culture and identification. The DNA extracted from the samples was analyzed for the presence of the target species using species-specific primers. RESULTS: Culture and polymerase chain reaction (PCR) identified the species in 23 and 77, respectively, of 100 root canals. Culture yielded the test organism in 19 of 50 (38%) of root canal samples from primary and in 4 of 50 (8%) from secondary/persistent infections. PCR yielded the test organisms in 41 of 50 (82%) and 36 of 50 (72%) of the, respectively, primary and secondary/persistent root canal infections studied. CONCLUSION: Gemella morbillorum was identified more frequently in primary endodontic infections than in secondary/persistent ones. A higher frequency of the target species was detected by PCR than by culture.

Chlorhexidine in Endodontics

Chemical auxiliary substances (CAS) are essential for a successful disinfection and cleanness of the root canals, being used during the instrumentation and if necessary, as antimicrobial intracanal medicaments. Different CAS have been proposed and used, among which sodium hypochlorite (NaOCl), chlorhexidine (CHX), 17% EDTA, citric acid, MTAD and 37% phosphoric acid solution. CHX has been used in Endodontics as an irrigating substance or intracanal medicament, as it possesses a wide range of antimicrobial activity, substantivity (residual antimicrobial activity), lower cytotoxicity than NaOCl whilst demonstrating efficient clinical performance, lubricating properties, rheological action (present in the gel presentation, keeping the debris in suspension); it inhibits metalloproteinase, is chemically stable, does not stain cloths, it is odorless, water soluble, among other properties. CHX has been recommended as an alternative to NaOCl, especially in cases of open apex, root resorption, foramen enlargement and root perforation, due to its biocompatibility, or in cases of allergy related to bleaching solutions. The aim of this paper is to review CHX's general use in the medical field and in dentistry; its chemical structure, presentation form and storage; mechanism of action; antimicrobial activity including substantivity, effects on biofilms and endotoxins, effects on coronal and apical microbial microleakage; tissue dissolution ability; interaction with endodontic irrigants; effects on dentin bonding, metalloproteinases and collagen fibrils; its use as intracanal medicament and diffusion into the dentinal tubules; its use as disinfectant agent of obturation cones; other uses in the endodontic therapy; and possible adverse effects, cytotoxicity and genotoxicity.

Resumo Substâncias químicas auxiliares (SQA) são essenciais para o processo de limpeza e desinfecção dos canais radiculares, sendo utilizadas durante a instrumentação dos canais radiculares e, se necessário, como medicamentos intracanais. Diferentes SQA têm sido propostas e utilizadas, entre elas: hipoclorito de sódio (NaOCl), clorexidina (CHX), EDTA 17%, ácido cítrico, MTAD e solução de ácido fosfórico a 37%. CHX tem sido usada na endodontia como SQA ou medicação intracanal. CHX possui uma ampla gama de atividade antimicrobiana; substantividade (atividade antimicrobiana residual); menor citotoxicidade que NaOCl, demonstrando desempenho clínico eficiente; propriedades de lubrificação; ação reológica (presente na apresentação gel, mantendo os detritos em suspensão); inibe metaloproteinases; é quimicamente estável; não mancha tecidos; é inodora; solúvel em água; entre outras propriedades. CHX tem sido recomendada como uma alternativa ao NaOCl, especialmente em casos de ápice aberto, reabsorção radicular, perfuração radicular e durante a ampliação foraminal, devido à sua biocompatibilidade, ou em casos de alergia ao NaOCl. O objetivo deste trabalho é fazer uma revisão do uso da clorexidina na medicina e na odontologia; sua estrutura química; forma de apresentação e armazenamento; mecanismo de ação, atividade antimicrobiana, incluindo, substantividade, efeitos sobre biofilmes e endotoxinas; efeito sobre infiltração microbiana coronal e apical; capacidade de dissolução do tecido; interação com os irrigantes; efeitos sobre a união à dentina, metaloproteinases e fibrilas de colágeno; a sua utilização como medicamento intracanal e difusão ...

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.

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 (p<0.05) from the growth inhibition zones produced by all NaOCl concentrations, including 5.25% (9.54 mm). However, there was no statistically significant difference (p>0.05) 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.

Behavior of subcutaneous tissue of rats in response to infected dentine associated with different endodontic irrigants / Comportamento do tecido subcutâneo de ratos frente à dentina infectada e associada a diferentes irrigantes endodônticos

PURPOSE: To compare rat subcutaneous connective tissue reaction to dentine contaminated with Enterococcus faecalis associated with 0.9% sterile saline, 5.25% sodium hypochlorite (NaOCl) and 2% chlorhexidine gel (CHX). METHODS: Dentine was crushed into powder and inoculated with E. faecalis. Tested substances were mixed with contaminated dentine and placed in polyethylene tubes. Ten male Wistar rats had their backs divided into four quadrants that received an implant containing one of the tested substances. An empty tube was used as a control. Five rats were randomly distributed for evaluation at time intervals of 24 hours and 72 hours. Tissue samples were histologically processed. Tissue reactions to experimental groups were evaluated under optical microscopes. RESULTS: Groups of 5.25% NaOCl induced greater inflammatory response after 24 hours and 72 hours. Compared to groups of 2% CHX, the groups of 0.9% sterile saline showed milder inflammatory reactions after 24 hours and more severe after 72 hours. CONCLUSION: The results indicate that 5.25% NaOCl group showed a higher inflammatory reaction to rat subcutaneous connective tissue and the 2% chlorhexidine group showed the least reaction.

OBJETIVO: Comparar a resposta do tecido subcutâneo de ratos frente a dentina contaminada com Enterococcus faecalis associado ao soro fisiológico 0.9% , hipoclorito de sódio 5.25% (NaOCl) ou clorexidina gel 2% (CHX). METODOLOGIA: Foi realizada a contaminação de dentina em pó com E. faecalis. As substâncias testadas foram misturadas com a dentina contaminada e inseridas em tubos de polietileno. Dez ratos Wistar tiveram os dorsos divididos em quatro quadrantes e cada quadrante recebeu um tubo com cada uma das misturas testadas. Um tubo vazio foi utilizado como controle. Os ratos foram distribuídos em dois grupos para avaliação no período de 24 e 72 horas. Os tecidos foram processados histologicamente e as reações teciduais foram avaliadas sobre microscopia de luz. RESULTADOS: Os grupos de NaOCl 5.25% promoveram maiores reações inflamatória após 24 e 72 horas. Quando comparado com os grupos de CHX 2%, os grupos de soro fisiológico 0.9% mostraram inflamação moderada após 24 horas e severa após 72 horas. CONCLUSÃO: Os resultados indicaram que o grupo de NaOCl 5.25% apresentou maior reação inflamatória aos tecidos subcutâneos de rato e que o grupo de CHX 2% apresentou menor reação inflamatória.

Microleakage evaluation of intraorifice sealing materials in endodontically treated teeth.

OBJECTIVE: Evaluate intraorifice sealing materials Cavit, Vitremer, and Flow-It for the prevention of coronal microleakage in root-canal treatment. STUDY DESIGN: Root-canal treatment was performed on 80 extracted human molars. Three millimeters of coronal gutta-percha was removed from the coronal aspect of the root canal and replaced with one of the 3 filling materials. After thermocycling (5 degrees C to 55 degrees C) and 5 days of immersion in dye, the teeth were cleared for stereomicroscope evaluation for evidence of dye penetration into the sealing material and along canal walls. RESULTS: All groups showed dye penetration into the root canal. Cavit sealed significantly better than the other groups (P < .01), preventing the coronal leakage in 90% of the specimens. Flow-It exhibited the highest leakage (65% of specimens) and did not differ significantly from the Vitremer group, which showed dye penetration in 55% of specimens. CONCLUSION: Cavit sealed significantly better than Vitremer and Flow-It when used as intraorifice filling materials.

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.

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 percent, 1 percent and 2 percent 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 percent chlorhexidine gluconate gel (11.79 mm), being significantly different (p<0.05) from the growth inhibition zones produced by all NaOClconcentrations, including 5.25 percent (9.54 mm). However, there was no statistically significant difference (p>0.05) 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.

O objetivo deste estudo foi avaliar in vitro a atividade antimicrobiana do gluconato de clorexidina gel, como irrigante endodôntico, comparando-o ao hipoclorito de sódio (NaOCl) e ao gluconato de clorexidina líquido. A atividade antimicrobiana das substâncias testadas foi avaliada pelo teste de difusão em ágar. As zonas de inibição de crescimento bacteriano produzidas pela clorexidina gel a 0,2 por cento; 1 por cento e 2 por cento foram observados frente a 5 espécies de bactérias anaeróbias facultativas e 4 espécies de anaeróbios estritos, Gram-negativos e produtores de pigmento negro; e comparados com os resultados obtidos pelo NaOCl e pela clorexidina líquida. As maiores zonas de inibição foram produzidas quando as bactérias testadas ficaram em contato com a clorexidina a 2 por cento em gel (11,79 mm), apresentando diferença estatisticamente significante (p<0,05) quando comparados às zonas de inibição de crescimento bacteriano produzidas por todas as concentrações avaliadas de NaOCl, incluindo 5,25 por cento (9,54 mm). No entanto, não houve diferença estatisticamente significante (p>0,05) comparando as zonas produzidas por concentrações equivalentes de clorexidina líquida ou gel. Os resultados indicaram que a clorexidina em gel tem grande potencial para ser usada como substância química auxiliar quanto às suas propriedades antimicrobianas.