Mechanism of action of Bioactive Endodontic Materials

Abstract A continuous search for bioactive materials capable of supporting the replacement of damaged pulp tissue, with effective sealing potential and biocompatibility, has represented the attention of studies over the last decades. This study involves a narrative review of the literature developed by searching representative research in PUBMED/MEDLINE and searches in textbooks associated with the mechanism of action of bioactive materials (calcium hydroxide, mineral trioxide aggregate (MTA), and calcium silicate cements). The reflective analysis of the particularities of the chemical elements of these materials, considering the tissue and antibacterial mechanism of action, allows a better understanding of the characteristics and similarities in their tissue responses. Calcium hydroxide paste remains the antibacterial substance of choice as intracanal dressing for the treatment of root canal system infections. Calcium silicate cements, including MTA, show a favorable biological response with the stimulation of mineralized tissue deposition in sealed areas when in contact with connective tissue. This is due to the similarity between the chemical elements, especially ionic dissociation, the potential stimulation of enzymes in tissues, and the contribution towards an alkaline environment due to the pH of these materials. The behavior of bioactive materials, especially MTA and the new calcium silicate cements in the biological sealing activity, has been shown to be effective. Contemporary endodontics has access to bioactive materials with similar properties, which can stimulate a biological seal in lateral and furcation root perforations, root-end fillings and root fillings, pulp capping, pulpotomy, apexification, and regenerative endodontic procedures, in addition to other clinical conditions.

Resumo Uma busca contínua de materiais bioativos com capacidade de substituir o tecido pulpar danificado, com efetiva capacidade de selamento e biocompatibilidade, tem representado a atenção e foco de muitos estudos ao longo das últimas décadas. Este estudo envolve uma revisão narrativa da literatura desenvolvida por meio de pesquisas representativas encontradas no PUBMED/MEDLINE e pesquisas em livros didáticos associadas ao mecanismo de ação de materiais bioativos (hidróxido de cálcio, agregado de trióxido mineral (MTA) e cimentos de silicato de cálcio). A presente análise reflexiva das particularidades dos elementos químicos destes materiais bioativos, considerando o mecanismo de ação tecidual e antibacteriano, possibilita um melhor entendimento das características e similaridades no comportamento tecidual. A pasta de hidróxido de cálcio continua sendo a substância antibacteriana de escolha como medicação intracanal para o tratamento das infecções do sistema de canais radiculares. Este fato se deve a disponibilidade química de íons cálcio e hidroxila do hidróxido de cálcio aos tecidos, e a inibição enzimática bacteriana. Os cimentos de silicato de cálcio, dentre os quais inclui o MTA, apresentam uma resposta biológica favorável ao estímulo à deposição de tecido mineralizado nas áreas seladas e em contato com tecido conjuntivo. Este fato é decorrente da similaridade entre os elementos químicos, em especial devido a dissociação iônica, ao potencial estímulo de enzimas teciduais, e a contribuição com um meio alcalino decorrente do pH destes materiais. O comportamento dos materiais bioativos, em especial o MTA e os novos cimentos de silicato de cálcio na atividade de selamento biológico mostraram efetivos. A endodontia contemporânea atualmente conta com o potencial de materiais bioativos com propriedades análogas capaz de estimular o selamento biológico em perfurações radiculares laterais e de furca, em obturações radiculares, capeamento pulpar, pulpotomia, apicificação e procedimentos endodônticos regenerativos, além de outras condições clínicas.

Method to determine the root canal spatial geometry using an algorithm of the e-Vol DX CBCT software

Abstract This study evaluated a method to determine the spatial geometry of root canal preparation (RCP) using navigation dynamics and a specific algorithm from a new CBCT software (e-Vol DX). CBCT scans of 168 root canals of mandibular molars were acquired before and after RCP, using nickel-titanium (NiTi) instruments (ProTaper Next, BioRace, Reciproc Blue, and WaveOne Gold). The spatial geometry of the root canals and the operative risk of disproportional wear of dentinal walls after RCP were evaluated using a new CBCT software. A 3-point scoring system was used after the measuring of cementum/dentin thickness before and after RCP in all root thirds. The root thirds were distributed into three parts of similar sizes, and the scores were categorized at three levels: 1. mild risk (1/3), 2. moderate risk (2/3), 3. severe risk (3/3). These levels were proposed according to the risk of creating disproportionate shapes, thin walls, or perforations. The data were analyzed statistically by Fischer's exact test (α = 5%). There were no significant differences in operative risk among the NiTi engine-driven systems, for the distal or mesial walls of all the root canal thirds (p>0.05). The spatial geometry method to assess operative risk allows clinical planning for a predictable enlargement of the root canal in all root thirds. Based on using a map-reading strategy on root canals in CBCT scans, NiTi engine-driven instruments did not present an increased operative risk during RCPs.

Resumo Este estudo avaliou um método para determinar a geometria espacial do preparo do canal radicular (PCR) usando uma dinâmica de navegação e um algoritmo específico do software e-Vol DX. Imagens de tomografia computadorizada de feixe cônico (TCFC) de 168 molares inferiores foram adquiridas antes e depois do PCR, usando instrumentos de níquel-titânio (NiTi) (ProTaper Next, BioRace, Reciproc Blue e WaveOne Gold). A geometria espacial dos canais radiculares e o risco operatório de desgaste desproporcional das paredes dentinárias após o preparo foram avaliados usando o software de TCFC e-Vol DX. Um sistema de Score de 3 pontos foi usado após a mensuração da espessura cemento/dentina antes e depois do PCR, em toda extensão dos canais radiculares. Os terços radiculares foram distribuídos em três partes de tamanhos semelhantes, e os Scores foram categorizados em três níveis: 1. risco leve (1/3), 2. risco moderado (2/3), 3. risco severo (3/3). Esses níveis foram propostos de acordo com o risco de criar formas desproporcionais, paredes finas ou perfurações radiculares. Os dados foram analisados estatisticamente pelo teste exato de Fischer ((=5%). Não houve diferenças significativas no risco operatório entre os sistemas de NiTi acionados a motor, para as paredes distal ou mesial em todos os terços do canal radicular (p>0,05). O método de geometria espacial para avaliar o risco operatório permite o planejamento clínico para um alargamento previsível do canal radicular em todos os terços radiculares. Com base no uso de uma estratégia de navegação dinâmica de canais radiculares de molares inferiores analisados em imagens de TCFC, os instrumentos de NiTi acionados estudados não apresentaram um aumento do risco operatório durante o preparo dos canais radiculares.

Does radiotherapy treatment alter the pulp condition in patients with head and neck cancer? A systematic review

Abstract The main purpose of this study was to answer the question: "Can radiotherapy cause changes in the dental pulp condition of patients treated with irradiation in the head and neck region?" Clinical observational studies in adults with head and neck cancer undergoing treatment with ionizing radiation, longitudinal or cross-sectional follow-up to measure oxygen saturation (SpO2), and/or pulp sensitivity test to cold stimulation, were considered eligible. A systematic literature search was performed in six different databases, including the gray literature, and in article references. Two independent evaluators selected the studies, extracted the data, recorded the data on electronic spreadsheets, and then evaluated the methodological quality using the Checklist for Quasi-Experimental Studies tool devised by JBI. The data were assessed qualitatively using the Synthesis Without Metanalysis (SWiM) guidelines. After removing the duplicate articles, carefully analyzing the titles and abstracts, and reading the papers in full, seven studies were included. Four of the studies evaluated applied the cold sensitivity test, two associated pulse oximetry and cold sensitivity, and only one used just pulse oximetry. Evaluation using the cold sensitivity test and pulse oximetry in the initial periods before radiotherapy showed a decrease in the sensitive response and in SpO2 levels during a maximum period of 1 year. However, analyses thereafter indicated a normal response in both tests from 5 to 6 years after the end of radiotherapy treatment. Radiotherapy causes changes in pulp behavior patterns in the short term; however, recovery and return to average values occurs after long periods.

Accuracy of periapical and panoramic radiography for detection of root morphologies: a comparative study

Abstract: Maxillary and mandibular incisors have increased risk for severe orthodontically induced inflammatory root resorption. A patient-related risk factor is aberrant root morphology. This study aimed to assess the frequency of detection of different root morphologies in anterior teeth using dental panoramic tomography (DPT) and long cone periapical radiographs (LCPAs). A retrospective cross-sectional design was used to assess a sample of 50 consecutive pre-treatment radiographic records of patients from a specialist orthodontic practice in Adelaide, Australia. A reference guide was developed that included three previously unreported morphologies: pipette and bent, bent and pointed, bent and blunt. Two trained and calibrated assessors examined each record against the inclusion criteria, then independently assessed each anterior tooth from DPTs and LCPAs to detect the type of root morphology present. Data were analysed using the chi-square statistical test. Radiographic records for 48 patients (48 DPTs and 161 LCPAs) were eligible, with 355 and 426 teeth on DPTs and LCPAs, respectively, included for assessment. Normal root morphology (119 teeth) was commonly observed in DPTs, while bent (154 teeth) was frequently observed using LCPAs. Mandibular incisors often had normal morphology in DPTs but bent in LCPAs. Bent was the most common morphology in maxillary lateral incisors using DPT and LCPAs, although maxillary centrals were mostly normal in DPTs but pointed in LCPAs. Differences using the two image acquisition methods were highly significant (p < 0.01). Aberrant root morphologies are more easily detected in anterior teeth using LCPAs compared to DPTs.

Cone-beam and micro-computed tomography for the assessment of root canal morphology: a systematic review

Abstract This study presents an overview of the accuracy of cone beam computed tomography (CBCT) compared with micro-computed tomography (μCT) in the assessment of root canal morphology of extracted human permanent teeth. A database search in PubMed, PubMed Central, Embase, Scopus, Opengrey, Scielo and Virtual Health Library was conducted which compared root canal morphology of extracted human permanent teeth on the accuracy of CBCT with μCT. In accordance with PRISMA statement guidelines, data were extracted on study characteristics, target mediators, sampling and assay techniques and the parameters associated with obtaining the image and ability to identify the root canal morphology. Amongst 2734 records, ten fulfilled the inclusion criteria. Four studies compared the accuracy of CBCT and μCT in the assessment of root canal morphology using Vertucci's classification, with at least one CBCT group or subgroup of each study presented high agreement compared to the μCT. Six studies assessed more detailed root canal morphology, including two articles that found a lack of agreement between these imaging systems. Risk of bias was deemed low in three studies, moderate in four and high in three. CBCT can be as accurate as μCT in the assessment of several morphological features of extracted human permanent teeth; however there are some exceptions related to the more detailed morphological aspects. Voxel size likely influences the ability to detect these features, though the different aspects of exposure setting used in studies components may be confounding factors. CBCT may be considered for the assessment of root canal morphology ex-vivo.

Limited evidence suggests benefits of single visit revascularization endodontic procedures - a systematic review

Abstract Revascularization endodontic procedures commonly require multiple treatment sessions. However, single visit procedures may be advantageous from the clinical and patient management standpoints. The purpose of this review was to evaluate the outcomes of single-visit revascularization endodontic procedures for the management of immature permanent teeth with non-vital pulp. Two electronic databases (Scopus and PubMed) were searched, from their inception to July 2018, for studies that assessed clinical and/or radiographic and/or histologic outcomes of single-visit revascularization endodontic procedures performed in immature permanent teeth with non-vital pulp. Case reports, animal studies and clinical trials were included. The quality of case reports was appraised by Joanna Briggs Institute Critical Appraisal Checklist for Case Reports. The quality of randomized clinical trials was assessed by the revised Cochrane risk of bias tool for randomized trials. The risk of bias for animal studies was assessed using SYRCLE's risk of bias tool. Tabulation followed by narrative synthesis was used to draw conclusions. Seven studies satisfied the selection criteria. Five were classified as case reports, one as a randomized clinical trial and one as animal study. The latter presented with a high risk of bias, whilst the remaining showed a low risk. The evidence supporting the potential use of single-visit revascularization endodontic procedures is scarce. Successful single-visit revascularization endodontic procedures commonly include the use of high concentrations of sodium hypochlorite and EDTA combined with the use of agitation systems. Further clinical trials with long term follow up are needed to confirm the results of the current review.

Resumo Os protocolos clínicos de procedimentos endodônticos de revascularização comumente requerem múltiplas sessões. Entretanto, procedimentos em única sessão podem apresentar vantagens clínicas relacionadas ao paciente. O objetivo desta revisão sistemática foi avaliar os resultados clínicos dos procedimentos endodônticos de revascularização para o manejo de dentes permanentes imaturos realizados em única visita. Duas bases de dados eletrônicas (Scopus e PubMed) foram utilizadas, do seu início à julho de 2018, buscando estudos que avaliaram resultados de procedimentos endodônticos clínicos e/ou radiográficos, e/ou histológicos da revascularização em sessão única realizados em dentes permanentes imaturos com necrose pulpar. Relatos de casos, estudos em animais e estudos clínicos foram incluídos e avaliados quanto à qualidade e risco de viés. A qualidade dos relatos de casos foi avaliada utilizando-se a ferramenta própria de análise crítica do Instituto Joanna Briggs. A qualidade dos estudos clínicos randomizados controlados foi analisada pela ferramenta de risco de viés da Cochrane. O risco de viés para os estudos em animais foi mensurado utilizando-se a ferramenta SYRCLE. Os dados foram tabulados e a síntese narrativa foi utilizada para análise dos mesmos. Sete estudos satisfizeram os critérios de inclusão. Cinco foram classificados como relatos de casos, um como ensaio clínico randomizado e um outro como estudo em modelo animal. Este último apresentou alto risco de viés, enquanto o restante dos estudos mostrou baixo risco. A evidência que apoia a utilização potencial de procedimentos endodônticos de revascularização em sessão única é escassa. Os procedimentos endodônticos de revascularização em sessão única geralmente incluem o uso de altas concentrações de hipoclorito de sódio e EDTA, combinadas com o uso de sistemas de agitação. Assim, estudos clínicos com longos períodos de acompanhamento são necessários para confirmação dos resultados do presente estudo.

Validation of self-reported history of root canal treatment in a southern Brazilian subpopulation

Abstract The aim of this study was to assess self-reported history of root canal treatment (SRHRCT) as a method for detecting the presence of root canal treatment (RCT) and apical periodontitis (AP) in a southern Brazilian subpopulation. In this cross-sectional study, 136 military police officers from the city of Porto Alegre, Brazil, were included. The participants were interviewed and full-mouth periapical radiographs were taken. A calibrated examiner determined the presence of RCT and AP by applying standardized criteria. The diagnostic accuracy of SRHRCT was calculated separately for RCT and AP. Accuracy, sensitivity, specificity, positive and negative predictive values (+PV and -PV), efficiency, and positive and negative likelihood ratios (+LR and -LR) were estimated. The mean age of the participants was 34.1 ± 10.4 years and 88.2% were males. Overall, SRHRCT demonstrated high sensitivity and specificity for RCT, but not for AP: sensitivity (RCT = 0.960, AP = 0.757) and specificity (RCT = 0.835, AP = 0.631). The estimated values for PV and LR were: +PV (RCT=0.777, AP=0.396), -PV (RCT = 0.972, AP = 0.890), +LR (RCT = 5.853, AP = 2.057), and -LR (RCT = 0.046, AP = 0.383). SRHRCT proved to be a good predictor of the presence of RCT, but a weak predictor of AP in this subpopulation.

Oximetria de pulso na avaliação da vitalidade pulpar: análise crítica / Pulse oximetry in evaluation of pulp vitality: critical analysis

O diagnóstico da condição pulpar é essencial para o estabelecimento do tratamento adequado, e continua sendo um desafio na prática clínica atual. Os testes pulpares térmicos e elétrico são os mais comumente utilizados, porém apresentam as limitações inerentes por avaliarem apenas a sensibilidade pulpar, através da aplicação de estímulos na superfície dentária. A vitalidade da polpa dentária está relacionada à sua vascularização, e testes que avaliam o fluxo sanguíneo pulpar têm sido desenvolvidos e estudados. A oximetria de pulso é amplamente utilizada na medicina para determinação dos níveis de saturação de oxigênio sanguíneos, e tem apresentado-se como recurso para determinação da vitalidade pulpar. Com a utilização de adaptadores, os níveis de saturação de oxigênio da polpa dentária têm sido determinados em diferentes condições clínicas, direcionando para um diagnóstico mais preciso. Resultados promissores obtidos em diversos estudos reforçam as vantagens do oxímetro de pulso em comparação aos testes de sensibilidade, por se tratar de um método mais acurado, objetivo, não invasivo e que não provoca dor e desconforto ao paciente. Nesta perspectiva, os avanços científicos e tecnológicos têm aprimorado o uso de métodos de diagnóstico pulpar inovadores, e o oxímetro de pulso é um potencial recurso para aplicação na rotina clínica dos cirurgiões-dentistas.

Dental pulp diagnosis is essential for the establishment of appropriate treatment and remains a challenge in current clinical practice. Thermal and electrical pulp tests are the most commonly used, but they have the inherent limitations of only evaluating the pulp sensitivity through the application of stimuli on the dental surface. The vitality of the dental pulp is related to its vascularization, and tests that evaluate pulp blood flow have been developed and studied. Pulse oximetry is widely used in medicine for determination of blood oxygen saturation levels and has been presented as a resource for pulp vitality determination. With use of adapters, the levels of oxygen saturation of the dental pulp have been determined in different clinical conditions, leading to a more accurate diagnosis. Promising results obtained in several studies reinforce the advantages of the pulse oximeter in comparison to the sensitivity tests, because it is a more accurate, objective, non-invasive method that does not cause pain and discomfort to the patient. In this perspective, scientific and technological advances have improved the use of innovative pulp diagnostic methods, and the pulse Oximeter is a potential resource for application in the clinical routine of dentists.

Effect of an Alcohol-Based Caries Detector on the Surface Tension of Sodium Hypochlorite Preparations

The purpose of this study was to evaluate the effect of an alcohol-based caries detector (Kurakay) on the surface tension of a conventional sodium hypochlorite (NaOCl) preparation, and a product containing a surface-active agent (Chlor-XTRA). The surface tensions of the following solutions were tested: NaOCl, a mixture of NaOCl and Kurakay 9:1 w/w, Chlor-XTRA, a mixture of Chlor-XTRA and Kurakay 9:1 w/w. Ten measurements per test solution were made at 20 C, using an optical method called the "Pendant drop method", with a commercially available apparatus. The addition of Kurakay reduced the surface tension for NaOCl (p<0.05) whilst no significant difference was detected for Chlor-XTRA (p>0.05). Statistically significant differences between the NaOCl and Chlor-XTRA groups were found (p<0.05). The addition of an alcohol-based caries detector resulted in a reduction of the original surface tension values for NaOCl only. Taking into account the fact that mixtures of NaOCl and Kurakay have been used to assess the penetration of root canal irrigants in vitro, the related changes in surface tension are a possible source of bias.

O objetivo deste estudo foi avaliar o efeito de um detector de cárie com álcool (Kurakay) sobre a tensão superficial de um preparado convencional de hipoclorito de sódio (NaOCl) e um produto contendo um agente surfactante (Chlor-XTRA). Foram testadas as tensões superficiais das seguintes soluções: NaOCl, uma mistura de NaOCl e Kurakay na proporção de 9:1 em peso, Chlor-XTRA e um mistura de Chlor-XTRA e Kurakay na proporção de 9:1 em peso. Dez medidas foram feitas com cada solução, a 20 °C, utilizando um método óptico chamado "Método da gota pendente" (Pendant drop method) usando aparelhos disponíveis. Adição do Kurakay reduziu a tensão superficial do NaOCl (p<0,05), mas não houve diferença significante para Chlor-XTRA (p>0,05). Foram encontradas diferenças estatisticamente significantes entre os grupos NaOCl e Chlor-XTRA (p<0,05). Adição de um detector de cárie com álcool resultou na diminuição do valor original da tensão superficial apenas para NaOCl. Considerando que as misturas de NaOCl e Kurakay tem sido usadas para estudar a penetração in vitro dos irrigantes radiculares, as diferenças acima são uma possível fonte de desvio nos resultados.

Root Canal Penetration of a Sodium Hypochlorite Mixture Using Sonic or Ultrasonic Activation

The purpose of this ex vivo study was to determine, in "open" and "closed" systems, whether the design has an influence on the penetration length of sodium hypochlorite mixed with a radiopaque contrast medium, measured in millimeters, when delivered using positive pressure (PP) and using sonic (SI) or passive ultrasonic (PUI) activation. Sixty single-rooted teeth were divided into two groups: open and closed systems (n=30). Root canal shaping was performed to a working length of 17 mm. The samples were divided into three sub-groups (n=10) according to irrigant delivery and activation: PP, and SI or PUI activation. By using radiographs, penetration length was measured, and vapor lock was assessed. For the closed group, the penetration distance means were: PP 15.715 (±0.898) mm, SI 16.299 (±0.738) mm and PUI 16.813 (±0.465) mm, with vapor lock occurring in 53.3% of the specimens. In the open group, penetration to 17 mm occurred in 97.6% of the samples, and no vapor lock occurred. Irrigant penetration and distribution evaluation using open and closed systems provide significantly different results. For closed systems, PUI is the most effective in delivering the irrigant to working length, followed by SI.

O objetivo deste estudo in vivo foi determinar, para os sistemas "abertos" e "fechados", se o design tem influência na penetração, em milímetros, do hipoclorito de sódio misturado com um meio radiopaco quando empregado na ativação com pressão positiva (PP) e ativação sônica (SI) ou ultrassônica passiva (PUI). Sessenta dentes unirradiculares foram divididos em dois grupos: sistema aberto e sistema fechado (n=30). Os canais radiculares foram trabalhados até um comprimento de trabalho de 17 mm. Os grupos foram subdivididos em três subgrupos (n=10) de acordo com a solução irrigadora e a ativação: PP, e ativação SI ou PUI. Usando radiografias, a distância de penetração foi medida e avaliado o vapor contido. Para o grupo fechado, as distâncias médias de penetração foram PP 15,715 (±0,898) mm, SI 16,299 (±0,738) mm e PUI 16,813 (±0,465) mm e houve vapor contido em 53,3% das amostras. No grupo aberto, houve penetração de 17 mm em 97.6% das amostras, sem contenção de vapor. A penetração do irrigante e avaliação da distribuição usando sistemas aberto e fechado produziram resultados significativamente diferentes. Para os sistemas fechados, PUI é mais eficaz para levar o irrigante até preencher o comprimento de trabalho, seguido por SI.

Effect of Super-Oxidized Water, Sodium Hypochlorite and EDTA on Dentin Microhardness

The present study aimed to evaluate the influence of the following irrigating solutions on the microhardness of root canal dentin: 2% sodium hypochlorite (2NaOCl), 5% sodium hypochlorite (5NaOCl), super-oxidized water (400 ppm Sterilox - Sx) and 17% EDTA (E). Eighty roots from bovine incisors were randomly divided into 8 groups (n=10): 2NaOCl, 5NaOCl, Sx, and 2NaOCl + E, 5NaOCl + E, Sx + E (associated with E as final irrigant for 5 min), E solely and distilled water (dH2O) as the negative control. Root canal preparation was performed by hand instruments, using one of the irrigation protocols for 30 min. Then, 5 mm of the cervical root third were cut out from each sample and subjected to the Vickers microhardness test, at two points, one at approximately 500-1000 µm from the root canal lumen (distance 1), and the other at approximately 500-1000 µm from the external root surface (distance 2). Data were analyzed by Wilcoxon and Kruskal-Wallis tests at 5% significance level. Microhardness values at distance 1 were significantly lower than those at distance 2 for all groups, except 5NaOCl and 5NaOCl + E groups (p>0.05). EDTA showed the lowest microhardness values. However, no statistically significant difference was detected among groups at distance 1 and EDTA was significantly different only from Sx at distance 2. In conclusion, all tested solutions showed lower microhardness at the most superficial root canal dentin layer compared to the one found near the external root surface, except 5NaOCl and 5NaOCl + E; EDTA promoted lower microhardness values in comparison to Sterilox at this site.

O presente estudo teve como objetivo avaliar a influência das seguintes soluções irrigadoras na microdureza da dentina do canal radicular: hipoclorito de sódio a 2% (NaOCl2), hipoclorito de sódio a 5% (NaOCl5), água superoxidada (Sterilox(r) 400 ppm - Sx) e EDTA a 17% (E). Oitenta raízes de incisivos bovinos foram divididas aleatoriamente em 8 grupos (n=10): NaOCl2, NaOCl5, Sx e NaOCl2 + E, NaOCl5 + E, Sx + E (associados ao E como irrigante final por 5 min), E isolado e água destilada (H2Od), como controle negativo. O preparo dos canais radiculares foi realizado com instrumentos manuais, usando um dos protocolos de irrigação por 30 min. A seguir, 5 mm do terço cervical de cada amostra foram cortados perpendicularmente e submetidos ao teste de microdureza de Vickers, em dois pontos, um aproximadamente 500-1000 µm da luz do canal radicular (distância 1), e o outro aproximadamente 500-1000 µm da superfície externa da raiz (distância 2). Os dados foram analisados pelos testes de Wilcoxon e Kruskal-Wallis com um nível de significância de 5%. Os valores de microdureza na distância 1 foram significativamente menores do que na distância 2 para todos os grupos, exceto NaOCl5 e NaOCl5 +E (p>0,05). O EDTA mostrou os menores valores de microdureza. No entanto, não foi detectada diferença estatisticamente significativa entre os grupos na distância 1 e o EDTA foi significativamente diferente apenas do Sx na distância 2. Pode-se concluir que todas as soluções testadas mostraram menor microdureza na camada de dentina mais superficial do canal radicular em comparação aos valores encontrados próximo à superfície radicular externa, exceto NaOCl5 e NaOCl5 + E; o EDTA promoveu menor microdureza em comparação ao Sterilox(r) neste ponto.

Analysis of bovine pulp tissue dissolution ability by photodynamic therapy: an in vitro study / Análise da capacidade de dissolução de tecido pulpar bovino através da terapia fotodinâmica: estudo in vitro

PURPOSE: To evaluate the bovine pulp tissue dissolution ability of photodynamic therapy. METHIDS: Twenty pieces of bovine pulp tissue were weighed and divided randomly into four groups (n=5), according to the cleaning protocol: G1 - distilled water (negative control), G2 - sodium hypochlorite 1 percent (positive control), G3 - photodynamic therapy, G4 - sodium hypochlorite 1 percent + photodynamic therapy. The observation of the events of dissolution was performed by two observers blinded in relation to the test using 2x magnification, recording time in minutes until complete tissue dissolution. The total observation time was 2 hours. The dissolution rate was calculated dividing the weight of the fragment pulp (mg) by the time of dissolution (mg/min). RESULTS: Only group 2 (NaOCl) was able to promote complete dissolution of pulp tissue. In the other groups there was no occurrence of complete dissolution of the samples. The mean dissolution time for samples from group 2 (NaOCl) was 1.26 mg/min. CONCLUSION: Only the sodium hypochlorite was able to dissolve the fragments of bovine pulp tissue and photodynamic therapy does not show ability to dissolve tissue.

OBJETIVO: Avaliar a capacidade de dissolução de tecido pulpar bovino com o uso da terapia fotodinâmica. METODOLOGIA: Vinte fragmentos de polpas bovinas foram pesados e distribuídos randomicamente em quatro grupos (n=5) de acordo com os seguintes protocolos de limpeza: G1 - água destilada (controle negativo), G2 - hipoclorito de sódio 1 por cento (controle positivo), G3 - terapia fotodinâmica, G4 - hipoclorito de sódio 1 por cento + terapia fotodinâmica. A observação dos eventos de dissolução foi realizada por dois observadores, cegados quanto aos grupos experimentais, com lupa de 2x de aumento, que registravam o tempo em minutos até a completa dissolução de tecido. O tempo total de observação foi de 2 horas. O cálculo da taxa de dissolução foi feito dividindo o peso do fragmento pelo tempo de dissolução (mg/min). RESULTADOS: Somente o grupo 2 (NaOCl 1 por cento) foi capaz de promover dissolução completa do tecido pulpar, tendo como média de dissolução 1,26 mg/min. CONCLUSÃO: Apenas o hipoclorito de sódio foi capaz de dissolver os fragmentos de tecido pulpar bovino e a terapia fotodinâmica não mostrou capacidade de dissolução tecidual.

Evaluation of the antimicrobial effect of super-oxidized water (Sterilox®) and sodium hypochlorite against Enterococcus faecalis in a bovine root canal model

ABSTRACT Ideally root canal irrigants should have, amongst other properties, antimicrobial action associated with a lack of toxicity against periapical tissues. Sodium hypochlorite (NaOCl) is a widely used root canal irrigant, however it has been shown to have a cytotoxic effect on vital tissue and therefore it is prudent to investigate alternative irrigants. Sterilox's Aquatine Alpha Electrolyte® belongs to the group of the super-oxidized waters; it consists of a mixture of oxidizing substances, and has been suggested to be used as root canal irrigant. Super-oxidized waters have been shown to provide efficient cleaning of root canal walls, and have been proposed to be used for the disinfection of medical equipment. OBJECTIVE: To compare the antimicrobial action against Enterococcus faecalis of NaOCl, Optident Sterilox Electrolyte Solution® and Sterilox's Aquatine Alpha Electrolyte® when used as irrigating solutions in a bovine root canal model. METHODOLOGY: Root sections were prepared and inoculated with E. faecalis JH2-2. After 10 days of incubation the root canals were irrigated using one of three solutions (NaOCl, Optident Sterilox Electrolyte Solution®and Sterilox's Aquatine Alpha Electrolyte®) and subsequently sampled by grinding dentin using drills. The debris was placed in BHI broth and dilutions were plated onto fresh agar plates to quantify growth. RESULTS: Sodium hypochlorite was the only irrigant to eliminate all bacteria. When the dilutions were made, although NaOCl was still statistically superior, Sterilox's Aquatine Alpha Electrolyte® solution was superior to Optident Sterilox Electrolyte Solution®. CONCLUSIONS: Under the conditions of this study Sterilox's Aquatine Alpha Electrolyte® appeared to have significantly more antimicrobial action compared to the Optident Sterilox Electrolyte Solution® alone, however NaOCl was the only solution able to consistently eradicate E. faecalis in the model.