Effect of peracetic acid used as single irrigant on the smear layer, adhesion, and penetrability of AH Plus.

The aim of this study was to evaluate the effect of peracetic acid (PAA) as a single irrigant on the smear layer, on the intraradicular dentinal bond strength, and on the penetrability of an epoxy-based resin sealer into the dentinal tubules. A total of 120 roots were distributed into 4 groups according to the irrigant used in root canal preparation: 1% PAA (PAA); 2.5% NaOCl followed by final irrigation with 17% EDTA and 2.5% NaOCl (NaOCl-EDTA-NaOCl); 2.5% NaOCl (NaOCl); and saline solution (SS). The smear layer was evaluated using scanning electron microscopy. The bond strength of an epoxy-based resin sealer (AH Plus) to root dentin was evaluated by the push-out test and penetrability of the sealer into dentinal tubules was observed by confocal laser microscopy. The results were analyzed by the Kruskal-Wallis and the Dunn post-test (α = 0.05). The use of 1% PAA as single root canal irrigant provided smear layer removal and improved the penetrability and bond strength of AH Plus to root dentin in a manner similar to that of the NaOCl-EDTA-NaOCl group (p > 0.05). The NaOCl and SS groups had higher values of smear layer and lower values of sealer penetrability and dentin bond strength than the PAA and NaOCl-EDTA-NaOCl groups (p < 0.05). Thus, 1% PAA has the potential to be used as a single irrigant in root canals.

Effect of endodontic retreatment on the bond strength of resin cements to root canal dentin.

PURPOSE: To evaluate the effect of endodontic retreatment on the bond strength of different cementation techniques (self-adhesive and conventional resin cement) through the push-out mechanical testing and the penetrability of resin cements to root dentin. METHODS: 60 human teeth with single oval-shaped canals were used (n=15) : G1 - Endodontic treatment and cementation with RelyX ARC (ETA); G2 - Endodontic treatment and cementation with U200 (ETU); G3 - Endodontic retreatment and cementation with RelyX ARC (ERA); G4 - Endodontic retreatment and cementation with U200 (ERU). The groups with conventional endodontic treatment were filled with AH plus (ETA and ETU), while the groups that were submitted to endodontic retreatment were initially filled with Endofill and afterwards with AH Plus. Each radicular third (cervical, middle, and apical, of each tooth) was submitted to push-out bond strength testing, followed by evaluation with confocal laser microscopy to determine the penetration of the resin cements, and scanning electron microscopy was used to evaluate the failure mode. The parametric data were evaluated by two-way ANOVA and Tukey tests, and non-parametric data by Kruskal-Wallis and Dunn tests (α< 0.05). RESULTS: The ETA group had higher bond strength values to intra-radicular dentin than the other groups in all root thirds (P< 0.05). Endodontic retreatment had a negative impact on the penetration and push-out bond strength of RelyX ARC and U200 cement, regardless of the analyzed radicular third. CLINICAL SIGNIFICANCE: The bond strength between fiber post and root dentin can be affected by several factors, such as technical failure, cementation technique, pretreatment of the dentin, type of post and adaptation. The endodontic retreatment interferes negatively on the bond strength and penetrability of RelyX ARC and U200 cements to dentin, regardless of the analyzed radicular third. Therefore, the endodontic retreatment might have an adverse effect due to over preparation and aggression to the root canal.

Effect of peracetic acid used as single irrigant on the smear layer, adhesion, and penetrability of AH Plus

Abstract The aim of this study was to evaluate the effect of peracetic acid (PAA) as a single irrigant on the smear layer, on the intraradicular dentinal bond strength, and on the penetrability of an epoxy-based resin sealer into the dentinal tubules. A total of 120 roots were distributed into 4 groups according to the irrigant used in root canal preparation: 1% PAA (PAA); 2.5% NaOCl followed by final irrigation with 17% EDTA and 2.5% NaOCl (NaOCl-EDTA-NaOCl); 2.5% NaOCl (NaOCl); and saline solution (SS). The smear layer was evaluated using scanning electron microscopy. The bond strength of an epoxy-based resin sealer (AH Plus) to root dentin was evaluated by the push-out test and penetrability of the sealer into dentinal tubules was observed by confocal laser microscopy. The results were analyzed by the Kruskal-Wallis and the Dunn post-test (α = 0.05). The use of 1% PAA as single root canal irrigant provided smear layer removal and improved the penetrability and bond strength of AH Plus to root dentin in a manner similar to that of the NaOCl-EDTA-NaOCl group (p > 0.05). The NaOCl and SS groups had higher values of smear layer and lower values of sealer penetrability and dentin bond strength than the PAA and NaOCl-EDTA-NaOCl groups (p < 0.05). Thus, 1% PAA has the potential to be used as a single irrigant in root canals.

Comparação entre radiografia interproximal convencional, radiografia digital e tomografia computadorizada de feixe cônico no diagnóstico de lesões oclusais de cárie ­ estudo in vitro / Comparison of convencional radiography, interproximal, digital and cone beam computed tomography in the assessment of occlusal caries ­ in vitro study

Objetivo: Comparar a radiografia interproximal (convencional e digital) e a tomografia computadorizada de feixe cônico quanto ao diagnóstico de lesões oclusais de cárie. Material e método: Os exames de imagem foram realizados em 145 terceiros molares e avaliados por dois especialistas em radiologia que classificaram as imagens quanto à presença de lesões de cárie oclusais. Foram aplicados os testes de Kappa, de McNemar e análise ROC associada aos testes de Mann-Whitney e Qui-quadrado. Resultados: Com o teste Kappa evidenciaram-se graus excelente e moderado de concordância para as avaliações intra e interexaminadores, respectivamente. A partir da aplicação do teste de McNemar identificou-se diferença estatisticamente significativa (p=0.0026) entre a proporção de dentes diagnosticados com lesão de cárie na radiografia convencional e na tomografia computadorizada de feixe cônico. Para a radiografia digital a diferença encontrada não foi significativa (p=0.2858). Todos os exames mostraram sensibilidade menor que a especificidade e, utilizando como parâmetro a tomografia, a radiografia digital apresentou resultados discretamente superiores para avaliação das lesões oclusais. Conclusão: As três modalidades diagnósticas estudadas são válidas para abordagem de lesões oclusais de cárie. A radiografia digital e a tomografia computadorizada de feixe cônico mostraram-se superiores para o diagnóstico dessa patologia.

Objective: Compare interproximal radiography (conventional and digital) and cone beam computed tomography in the assessment of occlusal caries. Material and Methods: The image studies were performed in 145 third molars and evaluated by two radiologists who rated the images for the presence of occlusal caries. Kappa, McNemar and ROC analysis associated with Mann-Whitney and Chi-square were the statistical tests applied. Results: Kappa test revealed excellent and moderate degree of agreement for intra and inter-evaluations, respectively. From the application of the McNemar test a statistically significant difference (p = 0.0026) between the proportion of teeth diagnosed with caries in conventional radiography and tomography was identified. For digital radiography the difference found was not significant (p = 0.2858). All examinations showed lower sensitivity than specificity. Selecting as parameter the tomographic image, digital radiography showed slightly higher results for the assessment of occlusal lesions. Conclusion: All the diagnostic modalities studied approach is valid for occlusal caries. Digital radiography and cone beam computed tomography proved to be better to the diagnosis of this pathology.

Proposta de uma técnica minimamente invasiva para drenagem de lesão periapical aguda: relato de caso e estratégia clínica / Proposal of a minimally invasive technique for acute periapical lesion drainage: a case report and clinical strategies

A lesão periapical aguda é causada por infecção presente no canal radicular, sendo caracterizada pela presença de exsudato purulento inflamatório nos tecidos perirradiculares. Esse exsudato pode estar localizado intra- e/ou extrabucal e, em alguns casos clínicos, há a necessidade de se realizar drenagem cirúrgica, fato que pode ocasionar desconforto ao paciente. O presente relato de caso descreve uma técnica minimamente invasiva para drenagem de lesão perirradicular aguda na região do incisivo lateral superior direito, utilizando uma sonda de aspiração traqueal conectada no sugador endodôntico. Essa técnica oferece uma drenagem cirúrgica indolor para o paciente e reduz o risco de difusão da infecção. Depois do acesso coronário do elemento envolvido, neutralização precoce do conteúdo séptico e o desbridamento do canal radicular, uma pequena incisão foi realizada na mucosa palatina e imediatamente uma sonda traqueal modificada, sob pressão negativa, foi utilizada para aspirar o exsudato purulento. Na sequência, depois da remissão dos sinais e sintomas agudos, a cirurgia com a obturação endodôntica simultânea do canal radicular foi realizada, utilizando-se um cimento à base de resina epóxi e condensação lateral ativa. A proservação foi realizada por 6 meses, por meio de exames clínicos e radiográficos, demonstrando satisfatória reparação óssea e adequada evolução clínica.

Effect of Carbamide Peroxide on the Push-out Bond Strength of Different Composition Glass-Ionomer Cement to Root Canal Dentin when used as Cervical Barrier.

AIM: To evaluate the effect of 37% carbamide peroxide on the bond strength of conventional or resin-modified glass-ionomer cements when used as a cervical barrier in endodontically-treated teeth. MATERIALS AND METHODS: After root canal instrumentation and obturation, 40 specimens of the cement-enamel junction were obtained after transversal root canal sectioning from human extracted canines. The root canal specimens were standardized and filled with the following materials (n = 10, each group): G1: zinc phosphate (control), G2: Ketac glass-ionomer, G3: vitrebond glass-ionomer or G4: GC GL glass-ionomer. After 24 hours, the specimens were subjected to an application of 37% carbamide peroxide for 21 days, changed each 7 days and stored in an artificial pulp chamber. The specimens were then submitted to push-out bond strength testing with an electromechanical test machine (EMIC) and the failure mode in each specimen was analyzed with confocal microscopy (LEXT). RESULTS: G3 and G4 showed higher bond strengths values than the other groups (p < 0.05), and were similar to each other (p > 0.05). G1 showed the lowest bond strength value (p < 0.05). CONCLUSION: Glass-ionomer cements showed higher bond strength values than the zinc phosphate cement, and resin-modified glass-ionomer cements presented the highest push-out values to root canal dentin (GC, GL and Vitrebond). CLINICAL SIGNIFICANCE: Glass ionomer cements are recommended to use as cervical barrier materials before the internal dental bleaching, but its efficiency is questionable.

Efeitos sobre as propriedades físico-químicas e atividade antimicrobiana de modificações na composição de um cimento de silicato de cálcio / Effects in physicochemical and antimicrobial properties of a new compositions of a calcium silicate-based cement

O presente estudo avaliou a atividade antimicrobiana, escoamento, pH e a liberação de cálcio do MTA Fillapex (MTAF) (G1) ou MTA Fillapex com 10% (em massa) de hidróxido de cálcio (HC) (MTAF10) (G2), comparados com o AH Plus (AP) (G3) e o Sealapex (SE) (G4). A atividade antimicrobiana foi realizada através de teste de difusão radial sobre Enterococos faecalis (29212). O escoamento foi realizado de acordo com a norma ISO 6876:2001. Os cimentos foram inseridos em tubos de polietileno e imersos em recipiente com água deionizada. Após 24 horas, 7, 14 e 28 dias os valores do pH e cálcio liberado foram mensurados. Os valores obtidos na liberação de cálcio foram analisados através dos testes de Kruskal Wallis e Dunn e a atividade antimicrobiana, pH e escoamento foram analisados através dos testes de ANOVA e Tukey (p=0,05). A atividade antimicrobiana foi similar entre os cimentos (p>0,05). G1 e G2 apresentaram respectivamente o maior e menor escoamento que os demais grupos (p<0,05). G2 e G4 apresentaram pH e liberação de cálcio maior que G3 (p<0,05), em todos os períodos. G1 apresentou maior pH que G3 (p<0,05), exceto no período de 7 dias (p>0,05). G4 apresentou maior pH do que G1 e G2, mas o cálcio liberado foi similar (p>0,05). G3 apresentou menor liberação de cálcio entre todos os grupos (p<0,05). A adição de 10% de HC no MTAF não alterou o pH e liberação de cálcio do cimento e reduziu o escoamento, porém fora das padronizações técnicas...

This study evaluated the antimicrobial activity, flow, pH and calcium release of MTA Fillapex (MTAF) (G1) or MTA Fillapex plus 10% in weight of calcium hydroxide powder (CH) (MTAF10) (G2), compared to AH Plus (AP) (G3) and Sealapex (SE) (G4). The flow test was performed according to ISO 6876:2001 requirements. The sealers were placed into plastic tubes and immersed in deionized water. After 24 hours, 7, 14 and 28 days the water of each tube was removed and tested to evaluate the pH values and the level of released calcium. Calcium release values were analyzed statistically by Kruskal Wallis and Dunn tests and antimicrobial activity, pH values and flow were analyzed by ANOVA and Tukey tests (α = 5%). The antimicrobial activity was similar among all groups (p>0.05). G1 presented higher flow among all sealers (p<0.05). The addition of 10% CH into MTAF reduced the flow (p<0.05), but in discordance with ISO requirements. G2 and G4 presented pH values and calcium release higher than G3 (p<0.05), in all periods. G1 presented pH value higher than G3 (p<0.05), except in 7 days period (p>0.05). G4 presented higher pH values than G1 and G2, but the calcium release was similar for all periods (p>0.05). G3 presented lower calcium release among all groups (p<0.05). The addition of 10% calcium hydroxide in MTA Fillapex caused reduction in flow and no negative interference in pH and/or calcium release. The flow obtained does not follow ISO requirements

Ability of different methods to fill retrograde cavities with MTA

Introduction: The Mineral Trioxide Aggregate (MTA) has excellent biological property. However, its consistency makes it difficult to be inserted into retrograde cavities. Objective:To evaluate the ability of different methods to fill retrograde cavities with MTA. Material and methods: Root canals of thirty single-rooted resin teeth were prepared and filled. After the cut of 3 mm short of apical third, retrograde cavities with 3 mm deep were prepared using an ultrasound device and retrotips (CVD, São José dos Campos, SP, Brazil). The retrograde preparation was evaluate by using an operative microscope (D.F. Vasconcellos, São Paulo, SP, Brazil). The teeth were randomly divided into three groups (n = 10), according to the method: 1) condenser (Trinity, São Paulo, SP, Brazil); 2) MTA applicator (Angelus, Londrina, Brazil) + condenser; 3) condenser associated with ultrasound (CVD, São José dos Campos, SP, Brazil). After the filling of retrograde cavities with white MTA (Angelus, Londrina, Brazil), teeth were radiographed using a digital system (Kodak RVG 6000, Rochester, NY, USA). The images were analyzed by UTHSCSA Image Tool 3.0 software. The percentage of filling was calculated by the proportion between the total area of retrograde cavity and the filled area. The radiographic density mean of each third of retrograde cavity filled with MTA was measured by using the histogram tool of the software. The results were submitted to ANOVA and Tukey tests, with 5% of significance. Results: There was no difference in percentage of filling among the groups (p > 0.05) (approximately 85%). By comparing the thirds, the condenser and MTA applicator groups showed higher density for apical and middle third than cervical third (p < 0.05). The ultrasound group presented similar density among the thirds. Conclusion: The filling ability was similar for the studied methods. Ultrasound promoted better distribution of MTA in retrograde cavity, but did not increase the density of material.