Influence of pH change and water storage on the sealing ability of two resin-based root-filling materials.

AIM: To evaluate the Influence of pH change and water storage up to 90 days on the sealing ability of two resin-based root-filling materials. MATERIALS AND METHODS: Forty-four human mandibular single-rooted teeth were instrumented and filled with gutta-percha/ AH Plus or Resilon/Epiphany SE (n=20 per group). Two teeth each were used as positive and negative controls. Specimens were set for 7 days under 100% humidity at 37°C. They were allocated into two subgroups (n=10) according to whether they were tested immediately or stored for up to 90 days in water before testing. Sealing ability was evaluated by passive dye penetration. Absorbance at 630 nm (in µg/ml) was measured by spectrophotometry. The pH values were obtained in triplicate. Data were submitted to ANOVA by post-hoc Tukey's test (α=0.05). RESULTS: Specimens filled with Resilon/Epiphany SE exhibited more leakage than specimens filled with gutta-percha/AH Plus at the immediate time point (p<0.001). No differences were detected between the groups after storage, or between the materials with pH changes after 30, 60 and 90 days (p>0.05). CONCLUSION: Gutta-percha/AH Plus provided superior sealing at the immediate time point. Water storage and pH changes did not Influence the sealing ability of tested materials. CLINICAL SIGNIFICANCE: These results suggest that Resilon/ Epiphany SE sealer offered no apparent advantage over the more conventional gutta-percha/AH Plus sealer technique in terms of sealing ability.

Dental fracture and chocolate candies: case report.

A complaint by a customer to a food company claimed that the consumption of a chocolate candy fractured his anterior teeth, due to its hard consistency. Fragments of the fractured teeth and the chocolate candy that supposedly caused it were collected, examined and photographed. Fragments presented caries, large restorations, and suggested previous endodontic treatment. To evaluate causation, the food company requested a laboratory analysis, which simulated the human bite on chocolate candies of the same brand. Human teeth were assembled in a simulating device of masticatory functions of apprehension and incision. Teeth used were either sound or with non-restored endodontic accesses, to simulate previous conditions of the collected fragments. Twenty chocolate candies, cooled in a freezer to 0 °C for 2 h were used as test foods, and were positioned between the teeth of the device at the moment of the test. The set was put in a dynamometer, programmed to apply increasing forces (rate of advance of 5 mm/min), until rupture (either of the specimen or of the teeth). The applied force, in N, at the time of fracture was recorded and analyzed. The average force to fracture the test food was 233.23 N. No tooth was fractured in the experiment. Forces ranging from 191.3 to 275.2 N, applied to chocolate candies were not sufficient to neither fracture human teeth nor cause any structural damage. It was concluded that the dental fracture occurred because of previous oral health conditions of the customer.

Influence of calcium hydroxide intracanal medication on bond strength of two endodontic resin-based sealers assessed by micropush-out test.

AIM: To evaluate the influence of calcium hydroxide (CH) paste used as intracanal medication on the bond strength of AH Plus (AH) and Epiphany (EP) sealers to root dentin. METHODOLOGY: Sixty palatal canals were prepared in human maxillary first molars, using a rotary system. Half of the specimens received distilled water, and the other ones received intracanal medication with CH for 14 days. Thereafter, the CH was removed and both groups were further divided into two subgroups, filled with either AH or EP. The test specimens were submitted to the micropush-out test at a speed of 0.5 mm min(-1) . Results were statistically analyzed with anova and Tukey's test at a 95% confidence level. RESULTS: The use of CH had statistically significant (P < 0.05) influence on AH only, increasing its bond strength from 19.7 ± 4.5 to 23.8 ± 2.5 (mean ± SD in MPa). In both EP groups, with (1.8 ± 0.5 MPa) and without (1.5 ± 0.9 MPa) CH, the bond strength values were statistically significantly lower than in either of the AH groups (P < 0.05). CONCLUSION: Calcium hydroxide used as intracanal medication for 14 days had a positive influence on the bond strength of AH to root dentin whereas the effect on EP was insignificant. Regardless of the intracanal medication used, AH showed considerably higher bond strength values compared with EP sealer.

Adhesion of four endodontic sealers to root dentin conditioned with different chemical solutions / Adesão de quatro cimentos endodônticos em dentina condicionada com diferentes soluções químicas

Objective - To evaluate in vitro adhesion of endodontic sealers Rickert, AH Plus, Sealapex and Epiphany to dentin previously conditioned with one of two different chemical solutions. Methods - A total of 80 specimens were made up with bovine incisive teeth that were prepared by cutting predetermined sections and wearing them, producing standard experimental samples. Forty samples were treated with 2.5% sodium hypochlorite and divided into four groups with 10 specimens each, to be coated with the different sealers. Dentin of other forty samples was treated with 17% EDTA, and these samples were also divided into four groups. Prepared specimens were hydrated uniformly, dried, bonded and kept at 37°C and 100% relative humidity. After 72 hours, specimens were analyzed using an Instron universal testing machine in traction mode. Data were analyzed by Kruskal-Wallis test (?=0.05). Results - EDTA treatment led to the greatest adhesiveness in all experimentalgroups. Conclusion - It was concluded that conditioning of the surface with chelating agents increase adhesiveness of the tested sealers and similar behavior was observed in the adhesion of epoxy-based and methacrylate-based sealers.

Objetivo - Avaliar in vitro a adesão dos cimentos endodônticos Rickert, AH Plus, Sealapex e Epiphany à dentina previamente tratada por duas soluções irrigadoras. Métodos - Foram empregados 80 corpos de prova obtidos a partir de dentes incisivos bovinos que foram preparados por cortes e desgastes pré-estabelecidos, resultando em modelos experimentais padronizados. Quarenta dessas amostras foram tratadas com hipoclorito de sódio 2,5% e subdivididas em quatro grupos de 10 espécimes para cada cimento. As demais 40 amostras tiveram a dentina tratada com EDTA a 17% e foram divididos igualmente em 4 grupos. Os espécimes preparados foram uniformemente hidratados, secos, receberam os cimentos, e foram mantidos sob umidade relativa a 37ºC. Após 72 horas os espécimes foram submetidos a testes de tração com auxilio da máquina de ensaio universal Instron, sendo os dados analisados pelo teste de Kruskal-Wallis (?=0.05). Resultados - O tratamento com EDTA proporcionou maiores índices de adesão para todos os grupos experimentais (p<0.05). Conclusão - Pode-se concluir que o tratamento da superfície com agente quelante, aumenta a capacidade de adesão dos cimentos testados. Não houve diferença na adesão dos cimentos a base de resina epóxica e a base de metacrilatos.

Análisis crítico de metodologías empleadas en la evaluación de selladores en endodoncia / Critical analysis of methodologies used in the evaluation of sealants in endodontics

La incompleta obturación del sistema de conductos radiculares es uno de los motivos del fracaso en el tratamiento endodóntico. La presencia de espacios en el material obturador puede permitir la filtración en los sentidos apical y coronario. A medida que nuevos materiales son propuestos, se deben realizar investigaciones para la evaluación de todas sus propiedades. Dentro de ellas se puede destacar la capacidad selladora del material obturador en el interior de los conductos radiculares. Varias metodologías han sido preconizadas para esta finalidad. La literatura indica que han sido cuestionables la falta de estandarización y correlación entre estos métodos y los resultados de estas investigaciones. La falta de métodos confiables hace que estos materiales sean empleados en la práctica clínica de forma enpírica, en lo que respecta a esta propiedad. El propósito de este trabajo fue analizar metodologías de evaluación de la capacidad selladora de materiales obturadores endodónticos, buscando estudiar detalladamente sus variables y correlacionar los resultados de estas investigaciones con la práctica clínica

The incomplete filling of the root canal systen is one of the reasons for endodontic treatment failure. The presence of gaps in the seal material can allow leakage into the apical and coronary senses. As new materials are proposed, investigations must be conducted for the evaluation of all its properties. Within then you can highlight the sealing capacity of the filling material inside the root canals. Several methods have been advocated for this purpose. Therefore, the literature points towards the lack of standardization and correlation between these methods and the results of these investigations have been questionable. The lack of reliable methods makes the clinical use of these materials enpirical. The goal of this paper is to discuss methodologies for assessing the sealing ability of endodontic filling materials, seeking to study in detail the variables and correlate the results of these researchs with the clinical practice

Análise das soluções de hipoclorito de sódioutilizadas por endodontistas / Evaluation of sodium hypochlorite solutionsused by endodontists

Introdução: O sucesso da terapia endodôntica está condicionado adiversos fatores, entre os quais o uso de substâncias químicas deboa qualidade. Objetivo: Neste trabalho investigaram-se algumascaracterísticas das soluções de hipoclorito de sódio utilizadas emclínicas de atendimento, tais como concentração, pH e armazenagem.Material e métodos: Para isso, distribuiu-se formulário com perguntasrelativas à solução empregada a 100 endodontistas, além de pedir-lhes100 ml do produto. As amostras foram levadas ao laboratório paraanálise por titulometria da concentração de cloro residual livre, bemcomo do pH das soluções, com o auxílio de um peagômetro. Resultados:Apenas 1% dos profissionais conhece o valor do pH das soluções. Dasamostras recolhidas, 36% apresentaram pH 9, 22% pH 10, 16% compH 13, 14% pH 12, 11% pH 11 e 1% pH 8. Quanto aos profissionais,37% mantinham seus frascos sob refrigeração e 67% em temperatura ambiente. Conclusão: Os endodontistas usam soluções de hipocloritode sódio diferentes daquelas que desejam por desconhecerem ascondições necessárias para a manutenção da estabilidade química.

Introduction: The success of endodontic therapy is conditioned byseveral variables, being the use of good quality chemical agents one ofthem. Objective: In this study, some characteristics of commonly usedsodium hypochlorite irrigants were investigated, such as: concentration,pH, and storage conditions. Material and methods: For this purpose, aquestionnaire comprising questions regarding the employed irrigant wassent to 100 endodontists. Besides that, a 100mL sample of the sodiumhypochlorite irrigant used by them was collected. Free residual chlorinedetermination was laboratorially carried out through titration method.Additionally, pH was measured, through peagameter reading. Results:Only 1% of the professionals did know the pH value of the solutionsused by them. Concerning to pH value, 36% of the solutions presentedpH 9; 22%, pH 10; 16%, pH 13; 14%, pH 12; 11%, pH 11; and 1%, pH8. 37% of the endodontists kept the solution flasks under refrigeration,and 67% kept them at environmental temperature. Conclusion: It can beconcluded that the endodontists are using altered hypochlorite solutionsbecause they fail to observe the necessary conditions for maintainingthe solution?s chemical stability.

Fagoterapia como alternativa no combate às infecções endodônticas / Phage therapy as an alternative in the fight against endodontic infections

O uso de diferentes tipos de medicação intracanal para o controle do processo infeccioso, principalmente nos casos em que há presença de micro-organismos resistentes às manobras de desinfecção, tem sido alvo de muitas pesquisas. Os micro-organismos resistentes foram selecionados à medida que a prescrição de antibióticos passou a ser indiscriminada pelos próprios profissionais das áreas da saúde. Apesar de centros de pesquisas nos Estados Unidos da América do Norte, França e Repúblicas Soviéticas continuarem os estudos sobre fagoterapia, somente na década de 1980 ela foi redescoberta, despertando novamente o interesse da comunidade científica mundial. A fagoterapia poderá ser usada, no futuro, isoladamente na eliminação de bactérias resistentes aos antibióticos, ou associada à antibioticoterapia, em casos nos quais há presença de bactérias ainda suscetíveis às drogas. O irreversível e preocupante aumento da resistência bacteriana aos quimioterápicos abriu um novo caminho à fagoterapia, principalmente em casos em que já se esgotaram as alternativas para controle de sinais e sintomas característicos dos processos infecciosos refratários.

Many studies have investigated diverse intracanal medications to control the infectious process, especially in cases of microorganisms that are resistant to disinfection procedures. Drug-resistant microorganisms have been proliferating because of the indiscriminate use of antibiotics by healthcare professionals. Although research centers in the United States, France, and former Soviet States never stopped conducting studies on phage therapy, this concept was only rediscovered in the 1980s, again drawing the interest of the global scientific community. In the future, phage therapy may be used alone to eliminate antibiotic-resistant bacteria, or together with antibiotic therapy in cases where antibiotics still work. The irreversible increase in drug-resistant bacteria is cause for concern and has created a new role for phage therapy, especially in cases where the alternatives to control the signs and symptoms of drug-resistant infectious processes have been exhausted.

Early antimicrobial activity of intracanal medications on the external root surface of periodontally compromised teeth.

OBJECTIVE: To verify the effect of scaling and root planing on the antimicrobial activity of intracanal medications on the external root surface of periodontally compromised teeth. METHOD AND MATERIALS: Forty single-rooted extracted teeth were randomly assigned for visible calculus removal or scaling and root planing. Samples were separated into four groups-chlorhexidine, tetracycline hydrochloride, calcium hydroxide, or saline solution-and immersed in semisolid media and seeded with Micrococcus luteus for 24 hours. The zones of inhibition were measured using a profile projector. RESULTS: Calcium hydroxide and saline solution did not show bacterial growth inhibition. Chlorhexidine and tetracycline showed the occurrence of zones of inhibition in 70% and 40% of specimens, respectively. CONCLUSION: Partial antimicrobial activity on the external root surface was found when chlorhexidine and tetracycline solutions were used as intracanal medications; however, root planing procedures may modify this condition.

Analysis of permeability and morphology of root canal dentin after Er,Cr:YSGG laser irradiation.

OBJECTIVE: The aim of this study was to evaluate the morphology and permeability of root canal walls irradiated with Er,Cr:YSGG laser after conventional endodontic treatment. BACKGROUND: Laser irradiation can be used for dentinal tubule exposure, smear layer removal, and disinfection. Another potential, interesting application is as an adjunct to endodontic treatment, especially in the intracanal medication phase. METHODS: Fifty-two single-rooted teeth had their crowns sectioned at the cementoenamel junction and were randomly divided into four groups (n = 13): G1: conventional preparation (CP) + irrigation with EDTA-T + rhodamine B dye solution associated with NDP (dexamethasone phosphate, paramonochlorophenol, polyethylenoglycol) (Rhod-NDP); G2: CP + EDTA-T + Er,Cr:YSGG laser irradiation 0.75 W + Rhod-NDP; G3: CP + EDTA-T + Er,Cr:YSGG 1.5 W + Rhod-NDP; G4: CP + EDTA-T + Er,Cr:YSGG 2.5 W + Rhod-NDP. For the permeability analysis (n = 9), teeth were transversely cut and two slices of each third were selected. The images were analyzed by ImageLab software (Softium Informática Ltda., São Paulo, SP, Brazil). Additional samples (n = 4) were examined by scanning electron microscopy. RESULTS: Data were analyzed statistically using the Kruskal-Wallis and Student-Newman-Keuls tests for the following areas: apical third (H = 23.4651): G1 (14.25)(a), G2 (17.66)(ab), G3 (26.50)(b), G4 (39.58)(c); medium (H = 23.1611): G1 (14.16)(a), G2 (16.66)(ab), G3 (28.83)(b), G4 (38.33)(b); and cervical (H = 32.4810): G1 (9.66)(a), G2 (20. 00)(ab), G3 (27.00)(b), G4 (41.33)(c), (p < 0.01). Despite the irregular aspect of laser irradiation along the canal walls, the parameters of 1.5 W and 2.5 W allowed morphologic modifications that increased dentinal permeability. CONCLUSIONS: Irradiation with Er,Cr:YSGG laser could be effective in endodontic treatment for increasing dentinal permeability.

Effect of surface sealants on marginal microleakage in Class V resin composite restorations.

PURPOSE: Surface sealants may reduce or avoid problems related to the marginal interface. The aim of this study was to evaluate the microleakage in resin composite Class V restorations sealed with an adhesive system (Xeno III [Dentsply, Konstanz, Germany]), a sealant for exposed dentin (Seal & Protect [Dentsply]), and two surface sealants (Fortify [Bisco, Lombard, IL, USA]; Optiguard [Kerr, Orange, CA, USA]). MATERIALS AND METHODS: Fifty cavities with margins in enamel were prepared on crowns of bovine teeth and restored with an adhesive system (Prime and Bond NT/Dentsply) and resin composite (Esthet X/Dentsply). They were separated into four groups for the application of the surface sealants, and a control group (without surface sealing). Thermal cycling with baths of 5 degrees C +/- 2 degrees C and 55 degrees C +/- 2 degrees C were performed in 600 cycles. The teeth were made impermeable, except for a 3-mm window around the restoration and immersed in a 50% silver nitrate solution for 8 hours. The crown was sectioned longitudinally and the cuts were analyzed by three independent evaluators, using a stereoscopic loupe with 10x magnification that attributed representative scores. Agreement among the examiners was evaluated by the Kappa test. RESULTS: The Kruskal-Wallis test and Dunn Method showed that there was significant difference between the Control and Seal & Protect groups. The Seal & Protect group presented the lowest degree of microleakage, followed by the Optiguard and Xeno III groups. The highest scores were obtained in the Control group. CONCLUSION: The sealant materials evaluated presented different rates of effectiveness, and Seal & Protect was the most effective in decreasing the degree of marginal microleakage. CLINICAL SIGNIFICANCE Although surface sealants or covering agents have been used to diminish microleakage, they may present different rates of effectiveness with regard to reducing the degree of marginal leakage. (J Esthet Restor Dent 21:397-406, 2009).

Shelf-life of a 2.5% sodium hypochlorite solution as determined by Arrhenius equation.

Accelerated stability tests are indicated to assess, within a short time, the degree of chemical degradation that may affect an active substance, either alone or in a formula, under normal storage conditions. This method is based on increased stress conditions to accelerate the rate of chemical degradation. Based on the equation of the straight line obtained as a function of the reaction order (at 50 and 70 degrees C) and using Arrhenius equation, the speed of the reaction was calculated for the temperature of 20 degrees C (normal storage conditions). This model of accelerated stability test makes it possible to predict the chemical stability of any active substance at any given moment, as long as the method to quantify the chemical substance is available. As an example of the applicability of Arrhenius equation in accelerated stability tests, a 2.5% sodium hypochlorite solution was analyzed due to its chemical instability. Iodometric titration was used to quantify free residual chlorine in the solutions. Based on data obtained keeping this solution at 50 and 70 degrees C, using Arrhenius equation and considering 2.0% of free residual chlorine as the minimum acceptable threshold, the shelf-life was equal to 166 days at 20 degrees C. This model, however, makes it possible to calculate shelf-life at any other given temperature.

Shelf-life of a 2.5 percent sodium hypochlorite solution as determined by arrhenius equation

Accelerated stability tests are indicated to assess, within a short time, the degree of chemical degradation that may affect an active substance, either alone or in a formula, under normal storage conditions. This method is based on increased stress conditions to accelerate the rate of chemical degradation. Based on the equation of the straight line obtained as a function of the reaction order (at 50 and 70 ºC) and using Arrhenius equation, the speed of the reaction was calculated for the temperature of 20 ºC (normal storage conditions). This model of accelerated stability test makes it possible to predict the chemical stability of any active substance at any given moment, as long as the method to quantify the chemical substance is available. As an example of the applicability of Arrhenius equation in accelerated stability tests, a 2.5 percent sodium hypochlorite solution was analyzed due to its chemical instability. Iodometric titration was used to quantify free residual chlorine in the solutions. Based on data obtained keeping this solution at 50 and 70 ºC, using Arrhenius equation and considering 2.0 percent of free residual chlorine as the minimum acceptable threshold, the shelf-life was equal to 166 days at 20 ºC. This model, however, makes it possible to calculate shelf-life at any other given temperature.

Testes acelerados de estabilidade são indicados para avaliar, em um curto período de tempo, o grau de degradação química que poderá afetar uma substância química, isoladamente ou quando inserida em uma fórmula, sob condições normais de armazenamento. Este método está fundamentado na intensificação das condições de estresse para acelerar a velocidade de degradação química. Baseando-se na equação da reta obtida e na ordem de reação determinada (a 50 e 70 ºC) e usando a equação de Arrhenius, a velocidade de reação foi calculada para a condição de temperatura de 20ºC (condições normais de armazenamento). Este modelo de teste acelerado de estabilidade torna possível a predição da estabilidade química de qualquer substância, em qualquer tempo, desde que o método de quantificação da substância química esteja disponível. Como exemplo da aplicabilidade da equação de Arrhenius em teste acelerado de estabilidade, uma solução de hipoclorito de sódio a 2,5 por cento foi analisada por ser quimicamente instável. A quantificação do cloro residual livre foi determinada através de titulação iodométrica. A partir dos dados obtidos decorrentes das amostras submetidas às temperaturas de 50 e 70 ºC e com o emprego da equação de Arrhenius, o tempo de prateleira obtido foi de 166 dias em temperatura de 20 ºC, considerando como limite inferior a concentração de 20 mg/mL de cloro residual livre. Este modelo, entretanto, possibilita o cálculo de tempo de prateleira em qualquer outra temperatura de interesse.

Apical and periapical tissues responses afterroot canal obturation with two calcium hydroxid based sealers in dogs teeth / Reações teciduais apicais e periapicais quandoda obturação de canais radiculares de cães por dois cimentos contendo hidróxido de cálcio

Introduction: At the ending of endodontic treatment, is very important that the choice of root canal’s sealer will be done by biological compatibility criterial, which could promote less inflammation, turning quicker and more effective the healing process. Objective and material and methods: The aim of this study was to evaluate the apical and periapical tissues reactions in dog’s teeth, after pulpectomy and root canal’s cleaning and shaping, which limit was the fisiological barrier of delta apical, and filling with gutta-percha and two calcium hydroxide based endodontics sealers, Sealapex® and Apexit®, by those hystopatological events in observation periods of 7, 21 and 45 days, making a comparison of inflammatory reactions and reparacional evolution that both materials promoted. Past all periods, the dogs were killed and histological cuts of teeth were obtained. Results: Through qualitative-quantitative analysis, Sealapex showed inflammatory level among mild and moderate in all periods, having a great improvement in healing process at 45 days. There was a biggest dispersion of Apexit in periapical tissue, which caused an intense macrophage activity, raising inflammatory level in last period. Conclusion: Regardless of the sealer used, there were observed necrosis in a few of delta apical’s ramifications, being mostly in tooth filling by Apexit. In both ways, Sealapex showed best results than Apexit, about increased inflammatory reaction and healing process.

Introdução: No término do tratamento endodôntico é imprescindível que a escolha dos componentes da obturação seja feita com critério em relação à compatibilidade biológica, visando tornar o processo de reparação mais rápido e efetivo. Objetivo e material e métodos: Este estudo teve o propósito de analisar as reações teciduais apicais e periapicais em prémolares de cães, após pulpectomia e preparo químico-cirúrgico, cujo limite foi definido em nível do delta apical, e obturação com cones de gutapercha e dois cimentos contendo hidróxido de cálcio – Sealapex® e Apexit®. Foram analisados os eventos histopatológicos em períodos de 7, 21 e 45 dias, a fim de comparar os fenômenos de inflamação e de reparação. Decorridos os períodos de observação, os cães foram sacrificados, e as peças, processadas para análise histológica. Resultados: Empregandose análise quantitativa-qualitativa, verificou-se que o cimento Sealapex® promoveu inflamação entre discreta e moderada em todos os períodos, que evoluiu para reparação aos 45 dias. Houve maior dispersão do cimento Apexit® no tecido periapical, que promoveu intensa atividade macrofágica na área, ampliando os fenômenos de inflamação, mesmo aos 45 dias. Conclusão: Ambos os cimentos provocaram necrose em algumas ramificações do delta apical, ocorrendo porém em maior número nos dentes obturados com Apexit®. Da comparação entre o emprego dos dois cimentos, o Sealapex® foi o que apresentou melhor tolerância tecidual e, por conseqüência, evolução de reparação mais favorável.

Análise da limpeza dentinária em canais radiculares preparados com um sistema rotatório e diferentes substâncias químicas / Analysis of the cleaning of root canal prepared with a rotary instrument system and different chemical substances

Objetivos: Avaliar, com auxílio de microscópio eletrônico de varredura e leituras computadorizadas, a limpeza da superfície dentinária radicular - terços cervical, médio e apical - em canais radiculares de incisivos inferiores humanos, preparados pelo sistema rotatório K3?ENDO e diferentes substâncias químicas. Métodos: Entre elas o hipoclorito de sódio a 2,5%, (pH 11,0), do creme de Endo PTC reagindo com hipoclorito de sódio 0,5% (pH 11,0), empregando-se essa em duas diferentes consistências; sua consistência normal (Endo PTC-N) e uma de menor densidade (Endo-PTC-L); e de um gel de clorexidina (Endogel®). Concluída essa fase, os grupos receberam irrigação-aspiração com soluções de hipoclorito de sódio a 0,5%, (pH 11,0) e de EDTA-T a 17%, exceto o grupo do Endogel®, que recebeu dois regimes de irrigação, em um, irrigaçãoaspiração final com 20mL de soro fisiológico e em outro irrigação com EDTA-T. As amostras foram então preparadas para microscopia eletrônica de varredura e suas imagens analisadas pelo programa Scion Image. Resultados: Os resultados revelaram diferença estatisticamente significante, sendo que o grupo do Endo-PTC-L se mostrou superior aos demais no terço médio e apical e o grupo do Endogel com irrigação de EDTA-T apenas no terço médio, não havendo diferença estatística entre eles. Conclusão: Concluiu-se que substâncias veiculadas em polietilenoglicol e em menor viscosidade ofereceram melhor padrão de limpeza.

Objectives: To evaluate, by scanning electronic microscopy and computerized readings, cleaning of the root dentin surface - cervical, middle and apical thirds - in human mandibular incisor root canals, prepared by the rotary system K3?ENDO and different chemical substances. Methods: Among these, 2.5% sodium hypochlorite, (pH 11.0), Endo PTC cream reacting with 0.5% sodium hypochlorite (pH 11.0), usingthis in two different consistencies; its normal consistency (Endo PTC-N) and a less dense version (Endo-PTC-L); and a chlorhexidine (Endogel®). When this phase ended, the groups received irrigation-aspiration with solutions of 0.5% sodium hypochlorite (pH 11.0) and 17% EDTA-T, except for the Endogel® group, which received two irrigation regimes, in one final irrigation-aspiration with 20 mL of physiological solution and in the other, irrigation with EDTA-T. After this the samples were prepared for SEM and their images were analyzed by the Scion Image program. Results: The results revealed statistically significant difference, with the Endo-PTC-L group shown to be superior to the others in the middle and apical thirds. Whereas for the Endogel group with EDTA-T irrigation, there was no statistical difference among them, only in the middle third. Conclusion: It was concluded that the substances with the vehicle polyethylene glycol and with lower viscosities offered a better standard of cleaning.

Horizontal root fractures: a case report.

This case report describes the treatment of an upper right central incisor with an intra-alveolar horizontal root fracture at the level of the middle third and an upper left central incisor with the horizontal root fracture in the cervical third. The root fractures were reduced and rigidly splinted for 4 months. The endodontic therapy was instituted in the upper left central incisor because there was no possibility of fracture repair due to the proximity of the fracture and the gingival sulcus. As soon as the diagnosis of pulp necrosis was established in the upper left lateral incisor, the endodontic treatment was performed. After 3 years and 9 months check-up appointments showed healing in the middle root third of the upper right central incisor and it responded within normal limits to pulp testing. Thus, there is no need for endodontic therapy on this tooth.

Knowledge of Brazilian general dentists and endodontists about the emergency management of dento-alveolar trauma.

The purpose of this study was to determine Brazilian dentists' knowledge of emergency management of dento-alveolar trauma. A two-part questionnaire containing questions on demographic data and knowledge were mailed to 230 general dental practitioners (GDPs) and 70 endodontists. Questionnaires were returned by 42.6% of the GDPs and 62.8% of the endodontists. The survey data were statistically analyzed using Mann-Whitney U-test for practitioners' knowledge and Pearson's correlation coefficient for association between knowledge scores and practitioner age or years since graduation. The mean knowledge score of endodontists was significantly greater than for GDPs (P<0.0001). Dentists with trauma experience in their practices and those who had attended postgraduate courses on dental trauma had a significant higher mean knowledge score. In contrast, there was a poor correlation between the knowledge score and the ages of the respondents (r=0.086) or the years since graduation (r=0.108). In conclusion, this survey showed a poor knowledge of dental trauma management among the surveyed dentists and highlights the need to develop strategies to improve the knowledge base in this area of dentistry for the benefit of the dental trauma patient.

Cytotoxicity analysis of alendronate on cultured endothelial cells and subcutaneous tissue. a pilot study.

The use of alendronate, a bisphosphonate which is able to inhibit bone resorption, in order to prevent dental root resorption after tooth replantation would be of clinical relevance. However, this drug must be biocompatible to the periapical tissues. The aim of this study was to analyze the effect of an alendronate paste in polyethyleneglycol (2 g ml(-1)) on endothelial cells in culture (in vitro) and on rat subcutaneous tissue (in vivo). For the in vitro study the paste was applied on round glass coverslips that were immersed into confluent cell cultures (clone Cips). The cell viability percentages of these cultures were obtained 0, 6 and 12 h after contact with the substance. As control, cultures that received plain coverslips were used. This analysis was carried out in triplicate using the Trypan blue dye exclusion assay. For the in vivo study the paste was introduced into polyethylene tubes that were placed into the rat subcutaneous tissue. The rats were killed 7 and 14 days later; then, the tissue sections stained with hematoxylin-eosin were analyzed. In vitro, the alendronate caused a significant decrease in the cell viability in 6 h (P < 0.05) and 12 h (P < 0.01), when compared with the control cultures. In vivo the tissue response was exuberant and similar at the two experimental times. There was a necrosis in a comprehensive area in contact with the open end of the tube. Presence of micro-abscesses and intense inflammatory infiltrate in the hypoderm permeating the muscle fibers and fat lobules were observed. In conclusion, the alendronate paste in polyethylene glycol as used showed to be highly cytotoxic in vitro as well as in vivo.

Dissolução do tecido pulpar bovino por duas substâncias químicas do preparo do canal radicular / Bovine pulp tissue dissolution by two root canal irrigant solutions

O presente trabalho avaliou a dissolução de polpas bovinas pelo gel de clorexidina a 2,0% e pela solução de hipoclorito de sódio - em diferentes concentrações e valores de pH - sob duas temperaturas. Os fragmentos de tecido pulpar foram imersos em clorexidina 2,0%, veiculado em gel de natrosol, e hipoclorito de sódio a 5,0%; 2,5%; 1,0%; e 0,5%, com pH em 7,0; 9,0; e 11,0; sob duas temperaturas: 27°C e 37°C, para período máximo de 120 minutos. Dois fragmentos pulpares foram colocados em água destilada como grupos controles. Os resultados mostraram que: 1 - As soluções de hipoclorito de sódio sofrem influência de pH, temperatura e concentração, nessa ordem decrescente, para agir sobre a dissolução do tecido pulpar bovino. 2 - O gel de clorexidina a 2,0%, bem como as soluções de hipoclorito de sódio a 0,5% (pH 7), e temperaturas entre 27°C e 37°C, não dissolveram tecidos orgânicos durante o tempo experimental. 3 - Os trabalhos de pesquisa que utilizam o hipoclorito de sódio deveriam especificar suas características de pH, temperatura e concentração. 4 - Em pH 11, podem-se utilizar soluções menos concentradas do hipoclorito de sódio para manter sua ação de dissolução do tecido orgânico. 5 - Apesar de não se ter um modelo ideal para aquecimento controlado das soluções de hipoclorito de sódio, estas devem ser aquecidas para aumentar sua eficácia sobre a dissolução de tecido orgânico.

Análise da ação antimicrobiana de medicações intracanal utilizadas em Endodontia / Analysis of antimicrobial action of root canal dressing used in Endodontics

Introdução - O objetivo do presente estudo foi determinar a ação antimicrobiana de duas substâncias - NDP e PRP - utilizadas como medicação intracanal em Endodontia, quando em contato como bactéria comumente encontrada na flora microbiana oral, o Staphylococcus aureus (ATCC 25923), em meios de cultura sólido e líquido. Materiais e Métodos - A infusão bacteriana foi preparada utilizando meio BHI, correspondente a 0,5 da escala McFarland. Para o meio sólido, foi realizado o experimento em duas camadas de meio de cultura sobre placa de Petri. Na base foram colocados 10ml de meio Müeller-Hinton e, após sua solidificação, uma outra camada, também de 10ml, preparada com infusão de bactéria diluída em 1 x 10 elevado a 6, meio BHI e 5ml de Müeller-Hinton dando a concentração final de 15 x 10 elevado a 5 UFC/ml. Feito isso, foram espalhados aleatoriamente na placa do tipo Petri, discos de papel filtro, previamente embebidos nas substâncias-teste, soro fisiológico, como controle negativo e ampicilina, como controle positivo. Para o teste em meio líquido, foram colocados em tubos 2ml de meio BHI, acrescidos de uma mistura de 5ml de infusão bacteriana e BHI, previamente preparada para uma concentração final de 5 x 10 elevado a 5 UFC/ml. Em cada tubo foi colocado apenas um disco de papel. As placas e os tubos foram incubados em estufa a 37°C por 24 horas. Resultados - Houve formação de halos de inibição quando do uso das medicações PRP e NDP. Conclusões - O PRP mostrou maiores halos de inibição, indicando maior potencial antimicrobiano. Em meio líquido houve crescimento bacteriano em todos os tubos

Avaliação do desgaste do terço cervical dos canais mésio-vetibulares de molares superiores submetidos a diferentes procedimentos de preparo de suas entradas / An evaluation of the coronal third flare in mesio-buccal canals of maxillary molars prepared with different procedures

Para o correto preparo químico-cirurgico de canais raiducalares curvos, é necessário que a cirurgia de acesso à câmara pulpar seja feita tomando-se alguns cuidados. Esses cuitdados envolvem o preparo da entrada do canal radicular, o qual representa desgaste suficiente para que o preparo químico-cirúrgico possa ocorrer com mínimo risco de sequelas, tais como: desvios, degraus, falsos canais ou perfurações. Este estudo comparou os seguintes meios de preparo da entrada de canais mésio-vestibulares de molares superiores: brocas dos tipos Gates-Glidden, Largo e Peeso, limas preparadas e limas preparadas associadas a broca do tipo Gates-Glidden. Os resultados nas distâncis mesial, diagonal e entre as entradas dos canais vestibulares, ficando com esta última os maiores registros. As brocas dos tipos Largo e Peeso realizaram desgaste excessivos, quando comparadas aos demais grupos. As brocas do tipo Gates-Glidden apresentaram bons resultados, tanto quando de sua utilização após o uso de lima preparadas, como quando empregados isoladamente