The Efficacy of Passive Ultrasonic Activation of Organic Solvents on Dissolving Two Root Canal Sealers

Introduction: The aim of this in vitro study was to evaluate the dissolving efficacy of eucalyptol and orange oil solvents associated with passive ultrasonic activation (PUA) in zinc oxide-eugenol (ZOE) based and epoxy resin-based root canal sealers. Methods and Materials: Seventy samples of each sealer were prepared and then randomized according to the solvent and the time of the ultrasonic activation (n=5). The mean amount of weight loss of sealers was calculated in percentages and was analyzed by using the Kruskal-Wallis and Bonferroni post-hoc tests. Results: The greatest values of weight loss were obtained with the ZOE sealer groups (P<0.05), regardless of the solvent that was used. An application of PUA for 3 min, with a renewal of orange oil solvent each min, showed the greatest percentage of weight loss in ZOE sealer compared to the others templates (P<0.05). Neither the solvent nor the different times had any influence on the weight loss of the resin sealer (P>0.05). Conclusion: The application of PUA with essential oils can be an effective method in dissolving ZOE based sealers.Keywords: Eucalyptol; Orange Oil; Retreatment; Solvent; Ultrasoun

Construction of synthetic carbonate plugs: A review and some recent developments

Plugs are cylindrical rocks with known dimensions that are extracted typically from reservoir formations with representative mineralogical compounds, petrophysical properties and oilfield fluids. They are used in the laboratory to understand the behaviour of oil in reservoirs. One of their applications is to study the screening of chemicals, such as surfactants and polymers, for enhanced oil recovery research before being applied in the reservoir. Many of Brazil’s pre-salt basins are located in ultra-deep waters, and the high heterogeneities of its offshore carbonate reservoirs make the extraction of representative rock samples difficult, risky and expensive. The literature reports the construction of synthetic plug samples that reproduce rocks as an alternative and viable solution for this issue. However, there is a lack of publications that focus on the construction of representative carbonate plugs that considers both the mineralogical composition and petrophysics properties, such as porosity and permeability. In this work, the construction of synthetic plugs is studied, using a combination of published methodologies to achieve an alternative construction of synthetic carbonate plugs for laboratory scale studies. Using a procedure based on the use of pulverized rock matrices with known particle sizes, uniaxial compaction, and probable CaCO3 solubility control by changing temperature and pH, it was possible to obtain synthetic carbonate plugs with a similar mineralogy to the natural carbonate reservoir. However, further studies are necessary to obtain more controlled petrophysical properties of such samples

Incidence of Dentinal Defects and Vertical Root Fractures after Endodontic Retreatment and Mechanical Cycling

Introduction: The aim of this study was to evaluate the incidence of dentinal defects and vertical root fractures (VRFs) after endodontic retreatment and mechanical cycling (MC). Methods and Materials: Two hundred mandibular premolars were selected. Forty teeth were left unprepared (control group). The remaining 160 root canals were prepared with ProTaper instruments and filled by using two different techniques [eighty with lateral compaction (LC) and eighty with single-cone (SC)]. Forty canals from each group (LC and SC) received no further treatment. The remaining eighty teeth were divided into two groups (LCR and SCR) (n=40) in order to undergo the removal of the root filling, re-preparation and refilling with lateral compaction and single-cone, respectively. All of the teeth were subjected to MC (1,000,000 cycles, 130 N, 2.2 Hz and 37°C). The roots were sectioned at 3, 6 and 9 mm from the apex and observed under 20× magnification. The defects were classified as: no defect, VRF and other defects. Statistical analysis was performed using the Fisher’s Exact test and the Chi-Squared tests (α=0.05). Results: MC alone did not promote any other defects or VRFs. Experimental groups presented higher dentinal defects than the control group (P=0.021). Retreatment groups did not present a higher amount of dentinal defects than the groups that were subjected to the first treatment (P>0.05). Conclusion: Endodontic treatment and retreatment, regardless of the filling technique and MC, did not influence the occurrence of dentinal defects or VRFs in the human premolars.Keywords: Defects; Endodontics; Retreatment; Root Cana

DESENVOLVIMENTO DE CONTROLE ADAPTÁVEL PARA DISPOSITIVOS MÓVEIS VOLTADO AO PÚBLICO INFANTIL

O mercado de games para dispositivos móveis apresenta grande potencial de desenvolvimento de acessórios, como controles, contudo os modelos disponíveis tendem a exibir problemas relacionados à ergonomia e à adaptabilidade a diferentes tamanhos de dispositivos. Desse modo, o presente artigo teve como objetivo relatar o processo de desenvolvimento de um controle adaptável para dispositivos móveis voltados para crianças. Como resultado, foi apresentado o redesign de um controle, de modo a contribuir na configuração desse equipamento com base em fatores como ergonomia, funcionalidade tátil, adaptabilidade, bem como critérios ambientais

Effect of passive ultrasonic irrigation in remotion of root material filling during retreatment : literature review

A remoção da guta percha e do cimento obturador são requisitos fundamentais para a realização do retratamento endodôntico, a fim de revelar restos de tecido necrótico e bactérias que podem ser responsáveis pela persistência da inflamação periapical e consequentemente pelo insucesso do tratamento endodôntico. A literatura documenta o uso da Irrigação Ultrassônica Passiva (IUP) durante o retratamento endodôntico, com o intuito de remover remanescentes de material obturador. A ação da IUP baseia-se na transmissão de energia acústica por meio de ondas ultrassônicas que são geradas a partir de um instrumento oscilando na solução irrigadora. Esse mecanismo permite que as soluções alcancem locais de difícil acesso no interior do canal radicular, removendo as sujidades e o material obturador remanescente. O objetivo deste trabalho foi avaliar o efeito da IUP na capacidade de remoção de material obturador e de limpeza das paredes do canal durante o retratamento endodôntico. Foi realizada uma revisão de literatura para identificar e explorar estudos que abordem o assunto, disponíveis nas bases de dados Scielo, Scopus e PubMed/MEDLINE. Após a coleta de dados, verificou-se que enquanto alguns estudos avaliam o uso de solventes somados a ação da IUP com NaOCl na remoção de material obturador durante o retratamento endodôntico, outros usam os solventes como solução irrigadora para a agitação ultrassônica. Contudo, independente da forma como a IUP foi empregada, em nenhum deles a IUP se mostrou superior aos métodos convencionais quanto a remoção de remanescentes de material obturador e limpeza das paredes do sistema de canais radiculares.The removal of gutta-percha and sealer are basic requirements for endodontic retreatment in order to reveal necrotic tissue debris and bacteria which may be responsible for persistence of periapical inflammation and consequently the failure of endodontic treatment. The literature documents the use of the Passive Ultrasonic Irrigation (PUI) during endodontic retreatment, in order to remove remaining filling material. The action of the PUI based on the acoustic energy transmission through ultrasonic waves that are generated from swings in the instrument irrigating solution. This mechanism allows the solutions to reach hard to reach places inside the root canal, removing the dirt and the remaining filling material. The aim of this study was evaluated the effect of PUI in removal of remaining filling material and cleaning de walls of the root canal during endodontic retreatment, available in Scielo databases, Scopus and PubMed / MEDLINE. After collecting data, it was found that while some studies evaluate the use of solvents added the action of PUI with NaOCl in removing filling material during endodontic retreatment, others use solvents such as irrigating solution for ultrasonic agitation. However, regardless of how the PUI was used, it none has proved superior to conventional methods in the removal of remaining filling material and cleaning the walls of the root canal system

Construction of synthetic carbonate plugs: A review and some recent developments

International audiencePlugs are cylindrical rocks with known dimensions that are extracted typically from reservoir formations with representative mineralogical compounds, petrophysical properties and oilfield fluids. They are used in the laboratory to understand the behaviour of oil in reservoirs. One of their applications is to study the screening of chemicals, such as surfactants and polymers, for enhanced oil recovery research before being applied in the reservoir. Many of Brazil’s pre-salt basins are located in ultra-deep waters, and the high heterogeneities of its offshore carbonate reservoirs make the extraction of representative rock samples difficult, risky and expensive. The literature reports the construction of synthetic plug samples that reproduce rocks as an alternative and viable solution for this issue. However, there is a lack of publications that focus on the construction of representative carbonate plugs that considers both the mineralogical composition and petrophysics properties, such as porosity and permeability. In this work, the construction of synthetic plugs is studied, using a combination of published methodologies to achieve an alternative construction of synthetic carbonate plugs for laboratory scale studies. Using a procedure based on the use of pulverized rock matrices with known particle sizes, uniaxial compaction, and probable CaCO3 solubility control by changing temperature and pH, it was possible to obtain synthetic carbonate plugs with a similar mineralogy to the natural carbonate reservoir. However, further studies are necessary to obtain more controlled petrophysical properties of such samples

Diferentes técnicas para o tratamento de dentes com rizogênese incompleta e necrose pulpar: uma revisão sistemática

Introduction: The objective of this systematic review was to compare the apexification techniques of calcium hydroxide (Ca(OH)2), or mineral trioxide aggregate (MTA), with the pulp regeneration technique, using cohort studies, and non-randomized and randomized clinical trials. Methods: The methodology was based on electronic research in the following databases: PubMed, MEDLINE, Google Scholar, SciELO, and LILACS. In addition, a manual search was carried out using the references that were listed in the articles found. Results: A total of 403 potentially eligible studies were found, with seven being included in the inclusion criteria of this systematic review. The seven studies involved a total of 312 teeth. The minimum time of a follow-up period was 12 months. The irrigation solution most used was sodium hypochlorite, for both of the apexification and revascularization techniques. The medication commonly chosen in the apexification groups was Ca(OH)2, with antibiotic triple paste in the revascularization groups. The clinical rate of success in the groups treated with revascularization varied from 76% to 100%, while in the groups treated with apexification, it ranged from 68% to 100%. Only two studies reached a success rate equal to 100%. Conclusions: Variable levels of evidence were observed in relation to the treatments. However, it was confirmed that revascularization is an excellent option since its outcomes produced a greater gain of thickness and root length, besides developing a decrease in the apical foramen.Introdução: O objetivo desta revisão sistemática foi comparar as técnicas de apexificação, com hidróxido de cálcio (Ca(OH)2) ou agregado trióxido mineral (MTA), com a técnica de regeneração pulpar, utilizando estudos coorte, ensaio clínico não randomizado e randomizado. Métodos: A metodologia foi baseada em pesquisa eletrônica nas seguintes bases de dados: PubMed, MEDLINE, Google Acadêmico, SciELO e LILACS. Além disso, foi realizada uma pesquisa manual utilizando as referências listadas nos artigos encontrados. Resultados: Foram encontrados 403 estudos potencialmente elegíveis, sendo sete incluídos nos critérios de inclusão desta revisão sistemática. Os sete estudos envolveram um total de 312 dentes. O tempo mínimo de um período de acompanhamento foi de 12 meses. A solução de irrigação mais utilizada foi o hipoclorito de sódio, para as técnicas de apexificação e revascularização. O medicamento comumente escolhido nos grupos de apexificação foi o Ca(OH)2, com pasta tripla antibiótica nos grupos de revascularização. A taxa clínica de sucesso nos grupos tratados com revascularização variou de 76% a 100%, enquanto nos grupos tratados com apexificação variou de 68% a 100%. Apenas dois estudos atingiram uma taxa de sucesso igual a 100%. Conclusões: Níveis variáveis de evidência foram observados em relação aos tratamentos. No entanto, confirmou-se que a revascularização é uma excelente opção, pois seus desfechos produzem maior ganho de espessura e comprimento radicular, além de diminuir o forame apical

Eficácia da irrigação ultrassônica passiva na remoção de hidróxido de cálcio

INTRODUÇÃO: Remanescentes de Hidróxido de Cálcio [Ca(OH)2] podem interferir na qualidade da obturação endodôntica. OBJETIVO : Avaliar a eficácia da Irrigação Ultrassônica Passiva (IUP) associada à técnica convencional na remoção de medicação intracanal à base de Ca(OH)2. METODOLOGIA: Trinta dentes humanos anteriores monorradiculares foram usados. Os canais radiculares foram preparados com instrumentos manuais tipo K e preenchidos com medicação intracanal à base de Ca(OH)2, contendo PMCC e propilenoglicol. Após sete dias, a pasta de Ca(OH)2 foi removida de todos os canais radiculares com um instrumento manual e irrigação de NaOCl 1% com seringa. Os espécimes foram randomizados em dois grupos (n=12) de acordo com a irrigação final: Irrigação Manual - agitação manual de EDTA 17 % e irrigação de NaOCl 1%; IUP - agitação ultrassônica de NaOCl 1% (três ativações de 20s) seguida da ativação de EDTA 17% por 1 min. O Grupo Controle (n=6) não recebeu medicação intracanal. Todos os espécimes foram clivados e a quantidade de Ca(OH)2 remanescente foi calculada com o auxílio do estereomicroscrópio (20×). Os testes Kruskall-Wallis e Wilcoxon foram utilizados para avaliar a porcentagem de Ca(OH)2 remanescente. RESULTADO: O grupo da IUP apresentou, estatisticamente, as menores porcentagens de Ca(OH)2 remanescente, quando comparado ao grupo da Irrigação Manual, independentemente dos terços analisados (P < 0,05). O terço apical apresentou a maior quantidade de medicação residual, em ambos os grupos (P < 0,05). CONCLUSÃO : A associação da IUP com a técnica convencional demonstrou ser mais eficiente na remoção de medicação intracanal à base de Ca(OH)2 do que a combinação da Irrigação Manual com a técnica convencional

Efficacy of passive ultrasonic irrigation in removing root filling material during endodontic retreatment

Abstract Introduction The aim of endodontic retreatment is to remove the previous root filling materials completely to allow for the subsequent steps of cleaning, canal shaping and filling replacement. Objective To evaluate the efficacy of passive ultrasonic irrigation (PUI) in the removal of residual root filling material after removing the bulk of the root filling with nickel-titanium rotary instruments. Material and method Eighteen mesial isthmus-containing roots of human mandibular molars were prepared and filled. The root canal filling was removed with the ProTaper Retreatment system and K-files. The specimens were randomized into 2 groups (n = 9), both irrigated with 2.5% NaOCl and 17% EDTA. In the conventional group, an irrigation syringe was used. In the PUI group, the PUI technique was used. The roots were sectioned longitudinally and evaluated under stereomicroscopy. Student&#8217;s t test was used to compare groups and the general linear model was used to compare the apical, cervical, and middle root thirds within each group, in regard to the percentages of remaining residual filling material. Result There was no statistically significant intergroup difference, irrespective of which root third was evaluated (P > 0.05). In the PUI group, the apical third showed a significantly higher percentage of residual filling material, in comparison with the cervical (P = 0.038) and middle (P = 0.029) thirds. Conclusion The PUI technique was not more effective than the conventional irrigation technique in removing residual root filling material during endodontic retreatment in root canals with a complex anatomy