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.

Differential Diagnosis and Treatment Proposal for Acute Endodontic Infection.

The objective of this study was to describe the main lesions that simulate clinically and propose a treatment protocol for acute endodontic infection. Signs and clinical symptoms of periodontal abscess, gingival abscess, odontoma, herpes simplex, pericoronitis, acute pulpitis and necrotizing ulcerative gingivitis/periodontitis (NUG/NUP) were described and compared with acute endodontic infections. A treatment protocol was described by optimizing the procedures in access cavity, microbial decontamination and detoxification of the root canal, apical debridement, intracanal and systemic medication and surgical drainage procedures. The convenience of the use of 5.25% sodium hypochlorite, root canal instrumentation using a crown-down technique, intracanal medication with 2% chlorhexidine or triple antibiotic paste and the convenience of the use of antibiotics, analgesics, and surgical drainage to solve cases of acute dentoalveolar abscess was discussed.

Different formulations of peracetic acid: effects on smear layer removal, dentine erosion, cytotoxicity and antibiofilm activity.

OBJECTIVE: To assess the effects of different peracetic acid (PAA) formulations on smear layer (SL) removal, dentine erosion, cytotoxicity, and antibiofilm activity. METHODOLOGY: SL removal and dentine erosion were assessed using 90 premolars, distributed into six groups, according to final irrigation: PAA formulations (1% Sigma, 1% Bacterend OX, 1% Arposept, and 0.09-0.15% Anioxyde), 17% ethylenediaminetetraacetic acid (EDTA), and water (control). Cytotoxicity was assessed by methyl-thiazol-tetrazolium (MTT) and neutral red assays. Antibacterial and antibiofilm effectiveness was evaluated against Enterococcus faecalis. For cytotoxicity and antibiofilm activity assessment, the 2.5% NaOCl was also included. RESULTS: EDTA, Sigma, and Bacterend OX removed more SL than Arposept, Anioxyde, and water (p<0.05). EDTA caused more severe dentine erosion than Sigma and Bacterend OX (p<0.05). Sigma and Bacterend OX had higher cytotoxicity than the other solutions (p<0.05). NaOCl, Bacterend OX, Sigma, and Anioxyde significantly reduced E. faecalis colony-forming units (CFU) (p<0.05). The 2.5% NaOCl solution promoted greater biofilm biomass reduction (p<0.05) than the other solutions. All PAA formulations promoted greater biomass reduction than 17% EDTA (p<0.05). CONCLUSIONS: Although Sigma and Bacterend OX had higher cytotoxicity, they had a SL removal capability similar to that of EDTA, were as effective as NaOCl against E. faecalis biofilm, and promoted less dentine erosion than EDTA. Arposept and Anioxyde failed to remove the SL, had lower cytotoxicity, and showed less bacterial activity than NaOCl.

Different formulations of peracetic acid: effects on smear layer removal, dentine erosion, cytotoxicity and antibiofilm activity

Abstract Objective: To assess the effects of different peracetic acid (PAA) formulations on smear layer (SL) removal, dentine erosion, cytotoxicity, and antibiofilm activity. Methodology: SL removal and dentine erosion were assessed using 90 premolars, distributed into six groups, according to final irrigation: PAA formulations (1% Sigma, 1% Bacterend OX, 1% Arposept, and 0.09-0.15% Anioxyde), 17% ethylenediaminetetraacetic acid (EDTA), and water (control). Cytotoxicity was assessed by methyl-thiazol-tetrazolium (MTT) and neutral red assays. Antibacterial and antibiofilm effectiveness was evaluated against Enterococcus faecalis. For cytotoxicity and antibiofilm activity assessment, the 2.5% NaOCl was also included. Results: EDTA, Sigma, and Bacterend OX removed more SL than Arposept, Anioxyde, and water (p<0.05). EDTA caused more severe dentine erosion than Sigma and Bacterend OX (p<0.05). Sigma and Bacterend OX had higher cytotoxicity than the other solutions (p<0.05). NaOCl, Bacterend OX, Sigma, and Anioxyde significantly reduced E. faecalis colony-forming units (CFU) (p<0.05). The 2.5% NaOCl solution promoted greater biofilm biomass reduction (p<0.05) than the other solutions. All PAA formulations promoted greater biomass reduction than 17% EDTA (p<0.05). Conclusions: Although Sigma and Bacterend OX had higher cytotoxicity, they had a SL removal capability similar to that of EDTA, were as effective as NaOCl against E. faecalis biofilm, and promoted less dentine erosion than EDTA. Arposept and Anioxyde failed to remove the SL, had lower cytotoxicity, and showed less bacterial activity than NaOCl.

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.

Efeitos da interação e soluções utilizadas na prevenção da formação do precipitado originado pela interação do hipoclorito de sódio e do digluconato de clorexidina e a repercurssão sobre a resistência de união de cimento obturador na dentina do canal radicular / Effecfts of different solutions irrigation or protocols to prevent the chemical precipitates formed by interaction between sodium hypochlorite and chlorhexidine gluconate and its repercussion on the bond strength of an epoxy-based sealer in radicular dentin

O objetivo do presente estudo foi avaliar a magnitude da precipitação de resíduos e seu efeito sobre a resistência de união de um cimento obturador endodôntico (AH Plus) na dentina radicular, após a utilização do protocolo de irrigação final com hipoclorito de sódio (NaOCl) a 2,5% e digluconato de clorexidina a 2% (CHX), intercaladas ou não com álcool isopropílico, água destilada ou soro fisiológico. No capítulo 1, inicialmente cem caninos humanos extraídos foram preparados com o instrumento F5 e irrigados com NaOCl a 2,5% e EDTA 17%. Cinquenta dentes foram divididos em 5 grupos (n = 10), de acordo com o protocolo de irrigação final: G1 (controle, sem irrigação final); G2 (solução de CHX); G3 (CHX gel); G4 (Concepsis) e G5 (CHX Plus). Em seguida, os espécimes foram clivados e a dentina do canal radicular analisada através de microscopia eletrônica de varredura (MEV), nos segmentos cervical-médio e médio-apical, a fim de detectar a presença de debris e smear layer. Outros cinquenta dentes foram tratados igualmente ao estudo anterior, obturados e submetidos ao teste de push out, nos terços cervical, médio e apical radicular. Os espécimes foram avaliados utilizando uma máquina universal de ensaios mecânicos. Para análise estatística foi utilizando o teste de Kruskal Wallis e Dunn (p = 0,05). No capítulo 2, inicialmente cinquenta caninos humanos extraídos foram instrumentados semelhante ao descrito no capítulo1 e distribuídos em 5 grupos (n = 10), de acordo com o protocolo de irrigação final . No G1, os canais radiculares foram irrigados com NaOCl 2,5% e EDTA 17% ; no G2, procedimentos semelhantes ao G1 foram realizados, exceto que a CHX 2% foi utilizada como solução de irrigação final. Nos demais grupos, o álcool isopropílico (G3), solução salina (G4) ou água destilada (G5) foram utilizados entre NaOCl e a CHX. Os espécimes foram clivados longitudinalmente e a superfície dentinária radicular submetida à análise em MEV, também para avaliar a presença de debris e smear layer, nos segmentos cervical-médio e médio-apical. Outros cinqüenta caninos humanos extraídos foram divididos em cinco grupos (n = 10) e realizados com os mesmos procedimentos descritos no estudo anterior. Após a obturação, foram seccionadas para obter secções nos terços cervical, médio e apical radicular e também submetidos ao teste de push out, identicamente ao citado no capítulo1. A análise estatística dos estudos foi realizada utilizando o teste de Kruskal Wallis e Dunn (p = 0,05). No capítulo 1, foi demonstrado que as formulações do CHX a 2% (solução pura, gel, Concepsis e CHX-Plus) utilizadas no protocolo de irrigação final ocasionaram a precipitação de debris e smear layer sobre a dentina radicular, tanto no segmento cervical-médio como no médio-apical. Entretanto, estes resíduos não reduziram a resistência de união da obturação dos canais radiculares quando utilizado o cimento endodôntico (AH Plus). No capítulo 2, foi observado que o álcool isopropílico, a solução salina e a água destilada não foram capazes de prevenir a precipitação de resíduos sobre a dentina. No entanto, estes resultados não interferiram negativamente nos valores da resistência de união do cimento endodôntico (AH Plus) na dentina radicular

The aim of this study was to evaluate the effects of the chemical interaction between different formulations of chlorhexidine gluconate solution and sodium hypochlorite and alternative protocols to prevent the chemical residues precipitation on radicular dentin. In chapter 1, the aim of the current study was to evaluate the presence of debris and smear layer after endodontic irrigation with different formulations of 2% chlorhexidine gluconate (CHX) and its effects on the push-out bond strength of an epoxy-based sealer on the radicular dentin. One hundred extracted human canines were prepared to F5 instrument and irrigated with 2.5% sodium hypochlorite (NaOCl) and 17% ethylenediaminetetraacetic acid. Fifty teeth were divided into five groups (n=10), according to the final irrigation protocol with different 2% CHX formulations: G1 (control, no final rinse irrigation), G2 (2% CHX solution), G3 (2% CHX gel), G4 (Concepsis), and G5 (CHX Plus). In sequence, the specimens were submitted to scanning electron microscopy (SEM) analysis, in the cervical-medium and mediumapical segments, to evaluate the presence of debris and smear layer. The other 50 teeth were treated equally to a SEM study, but the root canals filled with an epoxybased endodontic sealer and submitted to a push-out bond strength test, in the cervical, middle, and apical thirds. G2, G3, G4, and G5 provided higher precipitation of the debris and smear layer than G1 (p<0.05), but these groups were similar to each other (p>0.05), in both segments. The values obtained in the push out test did not differ between groups, independent of the radicular third (p>0.05). The CHXs formulations caused precipitation of the debris and smear layer on the radicular dentin, but these residues did not interfere in the push-out bond strength of the epoxy-based sealer. In chapter 2, the aim was to evaluate the effectiveness of isopropyl alcohol, saline or distilled water to prevent the precipitate formed between NaOCl and 2% CHX and its effect on the bond strength of an epoxy-based sealer in radicular dentine. Fifty extracted human canines (n =10) were instrumented. In G1, root canals were irrigated with 17% EDTA and 2.5% NaOCl; G2, procedures similar to G1, except that 2% CHX was used as final irrigation. In the other groups, intermediate flushes with isopropyl alcohol (G3), saline (G4) or distilled water (G5) were used between NaOCl and CHX. The specimens were submitted to SEM analysis to evaluate the presence of debris and smear layer, in the apical and cervical segments. In sequence, fifty extracted human canines were distributed into five groups (n = 10), similar to the SEM study. After the obturation, the roots were sectioned transversally to obtain dentine slices, in the cervical, middle and apical thirds. The specimens were submitted to a push-out bond strength test using an electromechanical testing machine. The statistical analysis for studies were performed using the Kruskal Wallis and Dunn´s tests (α = 5%). All groups presented similar amount of residues precipitated on the radicular dentine (P > 0.05). The pushout bond strength values were similar for all groups, independently of the radicular third evaluated (P > 0.05). Isopropyl alcohol, saline or distilled water failed to prevent the precipitation of residues on the root canal dentine, but these residues did not interfere on the push-out bond strength of the obturation. In conclusion, all formulations 2% CHX provided chemical precipitates on radicular dentin after 2.5% NaOCl irrigation, but this residues does not interfered in push-out bond strength of epoxy-based sealer on dentin