Lílian Ferreira Freitas

Relationship between the size of patency file and apical extrusion of sodium hypochlorite.

BACKGROUND Sodium hypochlorite (NaOCl) is the most widely used endodontic irrigant because of its excellent antimicrobial, organic tissue dissolving, and lubricating properties. However, it is highly cytotoxic to the periapical tissues. AIM This study evaluated in vitro the extrusion of 5.25% NaOCl through the apical foramina of mesiobuccal (MB) root canals of maxillary first molars in two experimental conditions: Before apical debridement and after apical debridement with different instrument sizes to ensure direct access to the apical foramen (apical patency). MATERIALS AND METHODS Coronal accesses were prepared in 17 teeth and the apical foramina of the distobuccal and palatal root canals were sealed. The teeth were held in acrylic receptacles with the roots turned upwards to reproduce their position in the maxillary dental arch. The receptacles were filled with a starch/KI solution (a reagent that changes its color to blue after contacting NaOCl) covering the roots. The experiment had two phases: P1: Irrigation of the MB canals with 5.25% NaOCl without previous establishment of apical patency; P2: Canal irrigation after use of size 10 K-file and size 15 Flexofile as patency files. Only specimens with no NaOCl extrusion in P1 were assigned to P2. NaOCl was delivered pressureless at the canal entrance. The moment that the starch/KI solution contacted NaOCl was captured on digital photographs. RESULTS AND CONCLUSIONS There was no NaOCl extrusion in nine specimens in P1, but all of these teeth had irrigant extrusion in P2. The 5.25% NaOCl used as an endodontic irrigant showed great capacity to extrude beyond both intact and small-sized apical foramina of MB root canals of maxillary first molars.

Clinical Comparison of the Effectiveness of Single-file Reciprocating Systems and Rotary Systems for Removal of Endotoxins and Cultivable Bacteria from Primarily Infected Root Canals

INTRODUCTION This clinical study was conducted to compare the effectiveness of single-file reciprocating systems and rotary systems in removing endotoxins and cultivable bacteria from primarily infected root canals. METHODS Forty-eight primarily infected root canals were selected and randomly divided into 4 groups: WaveOne (Dentsply Maillefer, Ballaigues, Switzerland) (n = 12); Reciproc (VDW, Munich, Germany) (n = 12), ProTaper (Dentsply Maillefer) (n = 12), and Mtwo (VDW) (n = 12). Samples were collected before and after chemomechanical preparation. The irrigation was performed by using 2.5% sodium hypochlorite. A chromogenic limulus amebocyte lysate assay test was used to quantify endotoxins. Culture techniques were used to determine bacterial colony-forming unit counts. RESULTS In the baseline samples (ie, samples collected before chemomechanical preparation), endotoxins and cultivable bacteria were recovered from 100% of the root canal samples. No differences were found in the median percentage values of endotoxin reduction achieved with reciprocating systems (ie, WaveOne [95.15%] and Reciproc [96.21%]) and with rotary systems (ie, ProTaper [97.98%] and Mtwo [96.34%]) (P < .05). Both single-file reciprocating systems (ie, WaveOne [99.45%] and Reciproc [99.93%]) and rotary systems (ProTaper [99.85%] and Mtwo [99.41%]) were effective in reducing the cultivable bacteria (all P < .05). Moreover, the culture analysis revealed no differences in bacterial load reduction (P > .05). CONCLUSIONS Both single-file reciprocating systems (ie, WaveOne and Reciproc instruments) and rotary systems (ie, ProTaper and Mtwo instruments) showed similar effectiveness in reducing endotoxins and cultivable bacteria from primarily infected root canals, but they were not able to eliminate them from all root canals analyzed.

Clinical Influence of Different Intracanal Medications on Th1-type and Th2-type Cytokine Responses in Apical Periodontitis

INTRODUCTION This clinical study assessed the influence of different intracanal medications on Th1-type and Th2-type cytokine responses in apical periodontitis and monitored the levels of bacteria from primarily infection during endodontic procedures. METHODS Thirty primarily infected teeth were randomly divided into 3 groups according to the medication selected: chlorhexidine (CHX), 2% CHX gel; Ca(OH)2/SSL, Ca(OH)2 + SSL; and Ca(OH)2/CHX, Ca(OH)2 + 2% CHX gel (all, n = 10). Bacterial sample was collected from root canals, and the interstitial fluid was sampled from lesions. Culture techniques were used to determine bacterial counts (colony-forming units/mL). Th1 (tumor necrosis factor-α, interferon-γ, and interleukin [IL]-2) and Th2 cytokines (IL-4, IL-5, and IL-13) were measured by enzyme-linked immunosorbent assay. RESULTS All intracanal medication protocols were effective in reducing the bacterial load from root canals (all P < .05) and lowering the levels of Th1-type cytokines in apical lesions (all P < .05), with no differences between them (P > .05). Both Ca(OH)2 treatment protocols significantly increased the levels of Th2-type cytokines (P < .05), with no differences between them (P > .05). Thus, chlorhexidine medication showed the lowest effectiveness in increasing the levels of Th2-type cytokine. After treatment, regardless of the type of medication, the linear regression analysis indicated the down-regulation of Th2-type cytokines by Th1-type cytokines. CONCLUSIONS All intracanal medication protocols were effective in reducing bacterial load and lowering the levels of Th1-type cytokines. Thus, the use of Ca(OH)2 medications contributed to the increase in the Th2-type cytokine response in apical periodontitis.

Estudo Comparativo Entre Duas Técnicas Obturadoras: Condensação Lateral X Híbrida de Tagger

Objective: To compare the quality and the homogeneity of the filling mass of the root canals gotten through two different filling techniques, the Lateral C...

Análise da Adaptação Marginal de Materiais Retrobturadores

Objetivo: Avaliar a capacidade de adaptacao de diferentes materiais retrobturadores as paredes cavitarias do preparo apical. Metodo: Foram realizadas apicetomia e preparo cavitario empregando-se ultra-som em 24 raizes palatinas de molares superiores (extraidos e conservados em timol a 1%). Para a fase de retrobturacao as raizes foram divididas aleatoriamente em 8 grupos contendo 3 amostras cada: G1 - amalgama, G2 - guta percha, G3 - OZE (Oxido de Zinco e Eugenol), G4 - IRM (Intermediate Restorative Material), G5 - N-Rickert, G6 - Ketac-CEM, G7 - Super-EBA, G8 - MTA (Agregado Trioxido Mineral). A seguir os especimes foram fotografados ao microscopio optico (MO) e eletronico de varredura (MEV) com aumentos de 50x e 150x. Os resultados foram analisados por 3 examinadores calibrados e estabelecidos escores (0- adaptacao do material retrobturador em todas as paredes do preparo apical, 1- ausencia da adaptacao do material retrobturador em uma ou duas paredes do preparo apical, 2-ausencia de adaptacao do material retrobturador em tres ou mais paredes do preparo apical). Os dados foram analisados atraves do teste de Kruskal Wallis. Resultados: A media dos escores entre as amostras foi: Amalgama(MO- 1,22 e MEV- 2), guta percha (MO- 1 e MEV- 2), OZE (MO- 1 eMEV- 1,55), IRM (MO- 2 e MEV- 2), N-Rickert (MO- 1,66 e MEV-1,88), Ketac-CEM (MO- 1,66 e MEV- 1,88), Super-Eba (MO- 0,22 eMEV- 0,55) e MTA (MO- 0 e MEV- 0). Verificou-se diferenca estatisticamente significante entre os grupos (p

Analise microbiologica de cones de guta-percha disponiveis no mercado brasileiro

Objective: To analyze the contaminati on on the surface of gutt apercha cones from diff erent manufacturers available in the nati onal market and to identi f...

Microbiological Analysis of Gutta-Percha Cones Available in the Brazilian Market

Objetivo: Analisar a contaminacao na superficie dos cones de guta-percha de diferentes fabricantes disponiveis no mercado nacional e identificar os microrganismos isolados. Metodo: 34 cones de guta-percha acessorios, provenientes de caixas lacradas ou manipuladas, foram analisados. Trinta cones foram divididos, aleatoriamente, em 6 grupos experimentais com 5 cones cada, diferenciados segundo o fabricante e a sua proveniencia (caixas lacradas ou manipuladas). Quatro cones oriundos de caixas lacrada ou manipulada foram utilizados como controles positivo (contaminado com saliva fresca) e negativo (imerso em solucao de hipoclorito de sodio a 5,25% por 1 minuto). As analises microbiologicas foram realizadas submergindo os cones em tubos contendo caldo Brain-Heart Infusion (BHI) e, posteriormente, semeando uma aliquota deste caldo em Agar sangue. A leitura foi realizada atraves da visualizacao de turvacao no caldo ou crescimento de colonias no meio solido. Os dados obtidos foram analisados pelos testes Kruskal-Wallis e Qui Quadrado com nivel de significância de 5%. Resultados: Observou-se crescimento bacteriano em 2 amostras. Os generos encontrados foram Staphylococcus e Bacillus. Os resultados indicaram que 6,67% dos cones de guta-percha de embalagens lacradas ou manipuladas estavam contaminados, mas nao houve diferenca estatistica entre os grupos experimentais. Conclusao: Existe um risco de contaminacao dos cones de guta-percha. Portanto estes materiais devem ser desinfetados a fim de garantir a seguranca necessaria para o sucesso do tratamento endodontico.

Ação do EDTA e do Ácido Cítrico Sobre a Dentina Radicular

1Professora Mestre da Disciplina de Endodonti a do Departamento de Odontoclinica da Universidade Federal Fluminense (UFF), Niteroi/RJ, Brasil. 2Professora Doutora da Disciplina de Endodonti a do Departamento de Odontoclinica da Universidade Federal Fluminense (UFF), Niteroi/RJ, Brasil. 3Especialista em Endodonti a pela Universidade Federal Fluminense (UFF), Niteroi/RJ, Brasil. 4Professora do Curso de Especializacao em Endodonti a da Universidade Federal Fluminense (UFF), Niteroi/RJ, Brasil. 5Aluna do Curso de Especializacao em Endodonti a da Universidade Federal Fluminense (UFF), Niteroi/RJ, Brasil.

Análise comparativa do escoamento de dois cimentos endodônticos:Endofll e AH plus

O escoamento de cimento obturador e fator importante no desempenho clinico do material, pois interfere em sua capacidade de penetrar nos tubulos dentinarios e canais laterais. A proposta deste estudo e avaliar a capacidade de escoamento de dois cimentos endodonticos: Endofill (cimento de Grossman) e AH Plus. Para tal analise, foram realizadas dez amostras de cada material, utilizando-se o metodo da extensibilidade de acordo com a especificacao 57 da ADA para cimentos endodonticos. Esse metodo refere-se a capacidade de se espalmar a superficie de uma preparacao, quando submetida a determinada forca. Seguindo a especificacao de cada fabricante, foram realizadas pesagem e manipulacao dos materiais, sendo 0,5ml do material introduzido em seringa descartavel e depositado sobre placa de vidro de 1 OX1 Ocm. Decorridos 180 segundos do inicio da manipulacao, foi colocado no centro da placa o cimento obturador e sobre este um conjunto composto por outra placa de vidro e uma carga adicional, perfazendo o total de 120g. Apos dez minutos do inicio da mistura, o peso adicional foi removido. As superficies das amostras foram medidas em seus comprimentos horizontal e vertical, com o uso de um paquimetro MITUTOYO (Japao), e por meio do contorno dos perimetros dos halos de escoamento das amostras dos cimentos testados com o auxilio de um programa de computador (Microsoft PowerPoint) a fim de que se obtivesse um parâmetro de comparacao. Foi feita a media aritmetica dos resultados, que foram tambem levados a analise estatistica, na qual pode ser observada uma significância no nivel de 1 por cento para ambos os metodos de medicao. Pode-se concluir que o AH Plus possui maior capacidade de escoamento que o Endofill (AU)