Dental students' performance and perceptions on canal preparation: a mixed methods study / Performance e percepções de estudantes de odontologia no preparo de canais: um estudo de métodos mistos

This study explored dental students' performance (quantitative data) and perceptions (qualitative data) on canal preparation with NiTi rotary vs. hand instruments and discussed interactions between technical findings and students' insights. A mixed methods design was used. Each student (n=20) instrumented two canals using hand K-files and two canals using ProTaper Universal® rotary Ni-Ti instruments. Participants had no previous experience with rotary instrumentation but were familiar with hand instrumentation. Quantitative data: apical transportation, working time for instrumentation and procedural errors were statistically analyzed. Qualitative data (students' perceptions) were collected and perceptions were identified from interview contents using thematic analysis. Lower level of apical transportation, fewer procedural errors (ledge/perforation/blockage), and a longer working time were associated with rotary instrumentation. Working time was shorter in the second canal instrumented with both techniques. Perceptions associated with hand instrumentation were: better domain and practice/confidence due to the students being used to the hand technique. Ni-Ti rotary instrumentation perceptions were: good initial expectations before its use, perceptions of doubts and difficulties concerning workability right after its first use, and increase in confidence after its second use in a second canal. It was concluded that: (i) students show a cautious attitude towards rotary instrumentation; (ii) confidence increases after rotary instrumentation of the second canal; (iii) students show good expectations in terms of optimizing root canal treatment with rotary instrumentation and they think it would be possible after some training; and (iv) Ni-Ti rotary instrumentation should be included in the undergraduate curriculum of dental schools (AU).

Este estudo explorou o desempenho dos estudantes de odontologia (dados quantitativos) e percepções (dados qualitativos) em relação ao preparo do canal com instrumentos rotatórios de Ni-Ti versus instrumentos manuais e discutiu interações entre os achados técnicos e os insights dos estudantes. O delineamento usado foi o de métodos mistos. Cada estudante (n=20) instrumentou dois canais usando instrumentos manuais e dois canais usando instrumentos rotatórios de Ni-Ti (ProTaper Universal®). Os participantes não tinham experiência com instrumentação rotatória, mas estavam familiarizados com instrumentação manual. Dados quantitativos, tais como transporte apical, tempo de trabalho para a instrumentação e erros de procedimento foram estatisticamente analisados. Dados qualitativos (percepções dos estudantes) foram coletados, sendo que as percepções foram identificadas a partir do conteúdo das entrevistas utilizando a análise temática. Baixos valores de transporte apical, poucos erros de procedimento (desvio/perfuração/bloqueio), e tempo de trabalho mais longo foram associados à instrumentação rotatória. O tempo de trabalho foi mais curto no segundo canal instrumentado por ambas as técnicas. Percepções associadas com instrumentação manual foram: melhor domínio e prática/segurança em virtude de os estudantes estarem acostumados com a técnica. Percepções para a instrumentação rotatória: boas expectativas iniciais, antes de utilizar; percepção de dúvidas e dificuldades em relação ao manejo do instrumento logo antes de utilizar; e, aumento da segurança na utilização depois do segundo uso, no segundo canal. A combinação dos achados quantitativos e qualitativos levou às seguintes conclusões: (i) os estudantes mostraram uma atitude de precaução frente à instrumentação rotatória de Ni-Ti; (ii) a segurança amentou depois da instrumentação do segundo canal; (iii) os estudantes mostraram expectativas boas em termos da otimização do tratamento de canal radicular com a instrumentação rotatória e pensam que isso será possível após algum treinamento; e (iv) a instrumentação rotatória com NiTi deveria ser incluído no currículo de graduação das escolas de odontologia (AU).

Filling analysis of artificial lateral canals after main canal obturation through three different endodontic sealers

Introduction and Objective: This study aimed to evaluate, in vitro, the filling ability of lateral canals after main canal obturation through three different endodontic sealers. Material and methods: Thirty single-rooted pre-molars were used and, six lateral canals were constructed on proximal surfaces and arranged in pairs at 3, 5 and 7 mm from the apex. After chemo-mechanical preparation, with size #40 memory instrument, the teeth were randomly assigned to three experimental groups, according to the root canal sealer applied: Endofill® (group A), Sealer 26® (group B) and MTA Fillapex® (group C). In all groups, we used active lateral condensation technique with gutta-percha associated with sealer. After obturation, the teeth were radiographed at buccolingual direction and the images were digitized. The analysis of endodontic sealer plug near the lateral canals was performed by calculating the area through Image Tool® software. Results and Conclusion: The data were subjected to parametric (Anova), and nonparametric (Kruskal-Wallis) tests, with significance level of 5%. There was no difference among the tested sealers for filling the lateral canals. Concerning to the positions of lateral canals, no differences were also found among sealer types, except at 7 mm from the apex, where MTA Fillapex® showed a significantly greater filling than Sealer 26®.

Analysis of remaining tissue after using LA AXXESS® drill in flaring of cervical mesial canals of mandibular molars

Introduction and Objective: The objective of this study was to analyze, in vitro, the remaining tissue at the risk zone in the mesial canals of the mandibular molars after cervical flaring using LA AXXESS® drill. Material and methods: Thirty molars were randomly divided into two experimental groups. Twenty teeth received cervical flaring using LA AXXESS® drill (group A), and ten were kept as control group (group B) without undergoing any kind of flaring. The teeth had their mesial roots cross-sectioned at a 3.5 mm standardized height apical to the cementum junction. Specimens were scanned and analyzed by a professional previously trained and calibrated. In order to measure the distances of the remaining tissue in relation to the furca, a Photoshop® program ruler version 7.0 was used. Results and Conclusion: It was possible, through statistical analysis using Student's t-test for paired and independent samples with a 5% significance level, to verify that there was no difference regarding the remaining tissue at the risk zone between the group that had cervical flaring and the control group.

Ludwig's angina: diagnosis and treatment

Introduction: Ludwig's angina is often an infection of odontogenic origin affecting the soft tissues of the submandibular, sublingual and submental area. Objective: This review aimed to analyze the existing literature regarding the clinical features, applications for diagnosis and treatment modalities of Ludwig's angina. Literature review: Because it is a disease of rapid evolution, and if not previously identified, may compromise the patient's general health and even lead to death. Conclusion: Therefore, it is important to identify the correct diagnosis based on careful and complementary clinical examination, together with an effective drug coverage and early surgical intervention to provide greater control of the patient's health.

Comparative analysis of the diameter of MTwo® system gutta-percha points in relation to their corresponding instruments

Introduction and Objective : This study aimed to compare the diameter of sizes 25/.06, 30/.05, 35/.04, 40/.04 and 25/.07 main gutta-percha point of MTwo® system in relation to their corresponding nickel-titanium instruments. Material and methods: For this purpose, the measurements of both the main gutta-percha points and their corresponding instruments were obtained with the aid of a caliper at the positions D1, D3 and D11. Twenty points and six instruments of each size were used. Results: Data were subjected to student t test, with a significance level of 5%. It could be observed that there was a variation in the diameter of the gutta-percha points in relation to the diameter of the instruments. At D1 and D3, size 25/.07 points had diameters significantly higher than their respective instruments. At D11, sizes 25/.06, 25/.07, 30/.05 and 35/.04 points also had significantly higher diameters. For size 40/.04 point, there were no statistically significant differences between the point and instrument diameters. Conclusion: Most of the main gutta-percha points of MTwo® system analyzed in this study showed significantly greater diameters than those of their corresponding instruments. Only the size 40/.04 points did not present significant differences in diameter compared with their corresponding instrument.

Fratura radicular oblíqua em incisivo central superior permanente: relato de caso / Fracture of upper central incisor permanent: Case report

Os casos de fraturas radiculares são extremamente graves em Odontologia e requerem, além de um preciso diagnóstico, o pronto e correto atendimento para que se possa obter um bom prognóstico do caso. Paciente do sexo masculino, 30 anos de idade compareceu ao consultório odontológico após um traumatismo do incisivo central superior direito permanente. O dente foi examinado, executados testes semiotécnicos, radiografia periapical e troca da contenção. Decorridos sete dias, executou-se o preparo do canal e medicação com pasta de hidróxido de cálcio. Após quatro meses, procedeu-se a obturação da porção coronária e posterior proservação do caso por dois anos, constatando-se normalidade dos tecidos e reparo da área da fratura. Nos casos de trauma dental que envolve fratura radicular é precípuo que se faça o diagnóstico da mesma e uma contenção rígida o mais breve possível para estabilizar o fragmento na região. Neste caso reportado, o curto espaço de tempo que o fragmento dental ficou fora do alvéolo, a colocação da medicação intracanal e uma correta imobilização foram fatores determinantes para o bom prognóstico.

The cases of root fractures in odontology are extremely serious and require, besides of an accurate diagnosis, the immediate and correct assistance in order to get a good prognostic of the case. A male, 30 years old, went to the dentist office after a permanent right maxillary central incisor trauma. The tooth was examined and semiotechnique tests were done, periapical and exchange of contention. After seven days, it was made a canal preparation and medication with calcium hydroxide paste. After four months, it was arranged in the filling of the coronal portion and later proservation of the case for two years, and we noted the normal tissue and repair the fracture area. In cases of dental trauma involving root fracture, it is preciput that we make the same diagnosis and a rigid restraint as soon as possible to stabilize the fragment in the region. In this case reported, the short time that the tooth fragment was out of the socket placement of an intracanal medication and right immobilization were crucial factors for good prognosis.

Verificação de alterações estruturais do vidro quando em contato com o EDTA 17% / Verification of structural changes of glass when submitted to 17% EDTA

Introdução e objetivo: Este estudo in vitro verificou por meio de microscopia eletrônica de varredura (MEV) alterações estruturais no vidro quando em contato com o ácido etilenodiaminotetracético (EDTA). Material e métodos: A metade inferior de quatro lamínulas de vidro permaneceu submersa em EDTA 17%, pH 7,3, por diferentes tempos (7 dias, 24 horas, 6 horas e 30 minutos). Como controle, examinou-se uma amostra que ficou parcialmente imersa em água destilada por 24 horas. As amostras foram analisadas em MEV e fotografadas com magnitudes de 19, 50, 100, 200, 400, 1.000, 2.000 e 3.000 vezes. Resultados: Constatou-se que nas quatro lamínulas que estiveram em contato com o EDTA houve formação de bolhas e rachaduras no vidro, independentemente do tempo testado. A amostra controle apresentou poucos defeitos no vidro e diferenciou-se das que ficaram em contato com a substância. Conclusão: O EDTA provocou alterações na estrutura do vidro.

Introduction and objective: This in vitro study verified, through SEM, the structural changes on glass surface when submitted to EDTA. Material and methods: Samples of 4 glass coverslip remained partially (lower half of the sample) immersed in 17% EDTA pH 7.3 for different periods (7 days, 24 hours, 6 hours and 30 minutes). The samples were analyzed by SEM and photographed with x19, 50, 100, 200, 400, 1000, 2000, and 3000 magnification. Results: It was found that the four glass samples submitted to EDTA showed blisters and cracks regardless of time. The control sample showed few defects differing from those in contact with EDTA. Conclusion: EDTA led to changes in the glass structure.

Atividade antimicrobiana do PMCC, por contato direto e vapor, frente ao Enterococcus faecalis e ao Staphylococcus aureus / PMCC antimicrobial activity, by direct contact and vapor, against Enterococcus faecalis and Staphylococcus aureus

O objetivo deste trabalho foi avaliar a atividade antimicrobiana do paramonoclorofenol canforado (PMCC), por contato direto e vapor contra o Enterococcus faecalis e Staphylococcus aureus. O método empregado foi o de difusão em ágar. Utilizaram-se dez dentes humanos extraidos (caninos superiores e inferiores, pré-molares superiores e inferiores), que foram transfixados a placas de Petry com resina acrílica auto-polimerizável, de forma que as coroas dentais ficassem acima da tampa destas placas. Ao redor dos ápices radiculares foi colado um cilindro de vidro de, aproximadamente, 5mm de diâmetro e 1,5 cm de altura. O teste por contato direto foi realizado com discos de papel filtro embebidos em 3µL de PMCC colocados diretamente sobre o meio de cultura inoculado com os microrganismos. Para o teste por vapor, o PMCC foi levado ao interior do canal com um cone de papel absorvente #40, onde permaneceu por 24 horas. Os resultados revelaram que o medicamento apresentou efeito antimicrobiano após contato direto com as culturas, formando halos de inibição bacteriana. Em relação aos vapores liberados pelo produto, pôde-se constatar que não houve nenhuma ação por vapor quando o fármaco esteve no canal radicular, pois houve crescimento bacteriano próximo a região do ápice radicular.

The aim of this study was to evaluate antibacterial activity of the canphorated paramonochorophenol (PMCC) by direct contact and vapor against Enterococcus faecalis and Staphylococcus aureus. The test of agar difusion was the method used. It were used human extracted teeth (maxillary and mandibulary canines and maxillary and mandibulary pre-molars) that were fixed on Petri slabs by acrylic resin in order to keep the tooth crown above of the slab cover. A glass cylinder (5 mm of diameter and 1,5 cm of height) was fixed around the root apex was fixed. The direct contact test was realized by papers disks were soaked with PMCC (3 µL) that put directly in contact with the agar. For the steam test, we put a paper point into canal root soaked with PMCC (3µL) that remained per 24 hours. The results showed that the PMCC was effective against micoorganisms when in direct contact with them, with zones of bacterial inhibition. Regarding the release of vapor by PMCC into de canal root, there was no any reaction, because there was bacterial growth.

Dissolution of bovine pulp tissue in solutions consisting of varying NaOCl concentrations and combined with EDTA.

This in vitro study evaluated (1) the dissolution of bovine pulp tissue in solutions consisting of varying NaOCl concentrations and combined with EDTA; and (2) the pH of these solutions before and after the experiment. The independent variables were the concentration and the volume of the solution. Thirty bovine pulps were divided in equal fragments, resulting in 90 fragments of pulp tissue. Each fragment was immersed in one of the following solutions: 1% NaOCl (4 ml), 2.5% NaOCl (4 ml), 1% NaOCl + 17% EDTA (2 ml : 2 ml), 1% NaOCl + 17% EDTA (1 ml : 3 ml), 2.5% NaOCl + 17% EDTA (2 ml : 2 ml), and 2.5% NaOCl + 17% EDTA (1 ml : 3 ml). The test solutions were dichotomized as either able or not able to dissolve the tissue, the latter being attributed when the dissolution of the pulp tissue was not complete within 48 hours. When the samples were able to dissolve the tissue, the time required for complete tissue dissolution was submitted to statistical analysis. The pH of the solutions was measured before and after the experiment. The pH variable was dichotomized as either changed or unchanged. The results demonstrated that the NaOCl solutions combined with 17% EDTA were not able to dissolve the tissue. The t-test revealed that the 2.5% NaOCl solution presented a lower mean dissolution time than the 1% NaOCl solution (p < 0.001). The pH of the solutions with equal volumes of NaOCl and EDTA decreased in 48 hours.

Dissolution of bovine pulp tissue in solutions consisting of varying NaOCl concentrations and combined with EDTA

This in vitro study evaluated (1) the dissolution of bovine pulp tissue in solutions consisting of varying NaOCl concentrations and combined with EDTA; and (2) the pH of these solutions before and after the experiment. The independent variables were the concentration and the volume of the solution. Thirty bovine pulps were divided in equal fragments, resulting in 90 fragments of pulp tissue. Each fragment was immersed in one of the following solutions: 1 percent NaOCl (4 ml), 2.5 percent NaOCl (4 ml), 1 percent NaOCl + 17 percent EDTA (2 ml : 2 ml), 1 percent NaOCl + 17 percent EDTA (1 ml : 3 ml), 2.5 percent NaOCl + 17 percent EDTA (2 ml : 2 ml), and 2.5 percent NaOCl + 17 percent EDTA (1 ml : 3 ml). The test solutions were dichotomized as either able or not able to dissolve the tissue, the latter being attributed when the dissolution of the pulp tissue was not complete within 48 hours. When the samples were able to dissolve the tissue, the time required for complete tissue dissolution was submitted to statistical analysis. The pH of the solutions was measured before and after the experiment. The pH variable was dichotomized as either changed or unchanged. The results demonstrated that the NaOCl solutions combined with 17 percent EDTA were not able to dissolve the tissue. The t-test revealed that the 2.5 percent NaOCl solution presented a lower mean dissolution time than the 1 percent NaOCl solution (p < 0.001). The pH of the solutions with equal volumes of NaOCl and EDTA decreased in 48 hours.

Análise da influência do grau de curvatura na ocorrência de desvios apicais após o preparo oscilatório em canais simulados / Analysis of the influence of degree of curvature in the occurrence of apical deviations after the oscillatory preparation in simulated root canals

Introdução e objetivo: Este estudo teve como objetivo analisar a influência do grau de curvatura na ocorrência de desvios apicais após a realização do preparo oscilatório. Material e métodos: Utilizaram-se 20 canais simulados com 21 mm de comprimento, os quais foram divididos em dois grupos experimentais com curvaturas de 20° e 40°. Os canais foram preparados com instrumentos de aço inoxidável acoplados a um contra-ângulo de sistema automatizado de movimentos oscilatórios com redução da velocidade de 10:1. Para a realização da análise do desvio, antes e após o preparo, os canais foram preenchidos com tinta nanquim e fotografados de forma padronizada com o auxílio de uma plataforma. Em seguida, as imagens obtidas foram manipuladas no programa Adobe Photoshop®, sobrepondo a imagem pré e pós-operatória, e com a ferramenta régua fez-se a medição dos desvios a 1 mm do comprimento de trabalho e no meio da área de curvatura. Os dados obtidos foram submetidos à Análise de Variância (Anova) com nível de significância de 5%. Resultados e conclusão: Por meio dos resultados obtidos observou-se que, quanto maior o grau de curvatura, maior foi o desvio. Já em relação ao local de análise, notou-se que na região a 1 mm do comprimento de trabalho houve maior desvio do que no ponto localizado no meio da área de curvatura.

Introduction and objective: This study aims to analyze the influence of degree of curvature in the occurrence of apical deviations after the oscillatory preparation. Material and methods: Twenty simulated root canals of 21 mm in length were divided into two experimental groups according to the degree of curvature: 20° and 40°. The canals were prepared using stainless steel instruments connected to a 10:1 speed reducing contra-angle handpiece with an automatized system of oscillatory movement. When analyzing the deviation, canals were filled with India ink and photographed in a standardized way with the aid of a platform, before and after the accomplishment of the preparation. In sequence, the images obtained were manipulated in Photoshop® Adobe program, preoperative and postoperative images were overlapped, and the deviation was measured with a ruler within 1 mm of working length and in the halfway of curvature. Data were submitted to analysis of variance (Anova) with a significance level of 5%. Results and conclusion: Through the results obtained, it was possible to see that the greater the degree of curvature, the greater the deviation. In relation to the place of analysis, it was possible to realize that there was more deviation in the region of 1 mm of working length than in the halfway of curvature.

Aumento de temperatura da superfície radicular durante preparo cervical usando broca LA Axxess ­ estudo in vitro / Temperature rise on the root surface during cervical preparation using LA Axxess bur ­ an in vitro study

Introdução e objetivo: A literatura carece de informações acercado possível aumento da temperatura na superfície externa radiculardurante a utilização das brocas LA Axxess. Este estudo in vitroobjetivou investigar o efeito, em relação à variação de temperatura,do diâmetro da broca LA Axxess e do tipo de movimento aplicado nopreparo cervical de canais mesiovestibulares (MV) e mesiolinguais(ML) de molares inferiores humanos extraídos. Material e métodos: Utilizaram-se 30 molares inferiores humanos extraídos que foramdivididos randomicamente em três grupos experimentais de acordocom o diâmetro da broca a ser usada: 20/.06, 35/.06 e 45/.06. Um únicooperador aplicou os seguintes movimentos durante o preparo cervicalnas amostras: 1) movimento contínuo no canal MV; 2) movimentointermitente no canal ML. Cada movimento teve duração de 5 segundos.A variação de temperatura foi medida por um termopar fixado na raize acoplado a um termômetro digital. Os valores correspondentes àvariação de temperatura foram submetidos a análise estatística pormeio da Análise de Variância (Anova) com nível de significância de5% em relação às variáveis independentes: diâmetro da broca e tipode movimento. Resultados: O diâmetro da broca não influenciou noaumento de temperatura. O movimento contínuo apresentou umaelevação significativa na temperatura externa radicular em relação aomovimento intermitente. Conclusão: O emprego das brocas LA Axxess,durante 5 segundos no preparo cervical, é seguro em relação ao aumentode temperatura, independentemente do diâmetro da broca e do tipo demovimento aplicado.

Introduction and objective: There is very little information on thescientific literature regarding the temperature rise on the outer rootsurface during cervical preparation using LA Axxess burs. The aim ofthis in vitro study was to investigate the effect, regarding the temperaturevariation, of the diameter of the LA Axxess bur and the type of movementapplied during cervical preparation of mesiobuccal (MB) and mesiolingual(ML) root canals of extracted mandibular human molars. Material andmethods: 30 extracted mandibular human molars were randomlydivided into three experimental groups according to the diameter ofthe bur to be used: 20/.06, 35/.06 and 45./06. A single operator appliedthe following movements on the samples during cervical preparation:1) continuous movement in the MB root canal; 2) intermittent movementin the ML root canal. Each movement lasted 5 seconds. Temperaturevariation was measured by a thermocouple fixed on the root andconnected to a digital thermometer. Variation temperature data wasanalyzed through ANOVA test with significance level of 5% in relation tothe independent variables: diameter of the bur and type of movement.Results: The diameter of the bur did not influence on the temperaturerise. The continuous movement showed a higher significant rise on theouter root temperature than the intermittent movement. Conclusion:The use of LA Axxess burs on cervical preparation during 5 seconds issafe in relation to the temperature rise regardless the diameter of thebur and the type of movement applied.

Análise do desgaste promovido no terço apical em canais simulados após preparo endodôntico com o Sistema K3 de conicidade.04 / Wear analysis promoted in simulated canals apical third after endodontic preparation with K3 Taper.04 System

Analisou-se o desgaste no terço apical de canais simulados após instrumentação com o Sistema K3 de conicidade.04. Utilizaram-se 12 jogos de instrumentos do Sistema K3 e 12 canais simulados confeccionados com resina epóxi transparente. Os instrumentos foram empregados em canais com curvaturas de 20 e 40 graus. Os canais foram fotografados antes da instrumentação e após a utilização dos instrumentos que prepararam o batente apical: 30, 35, 40 e 45. As imagens foramsobrepostas no programa Adobe Photoshop CS2 versão 9.0 e mediu-se o desgaste, em milímetros, para fora da curva em dois locais: 1 (local A) e 5 (local B) milímetros aquém do comprimento de trabalho. Por meio da Análise de Variância estudou-se a existência de interação entre três fatores: curvatura do canal, calibre do instrumento e local da curva. Nos canais de 20º, em ambos os locais, a quantidade de desgaste promovido pelo instrumento de calibre 40 não diferiu significativamente do desgaste promovido pelo calibre 35. Nos canais de 40º, no local A, não houve diferença estatística entre o desgaste promovido pelos quatro diferentes calibres de instrumentos. Houve desvio, para o lado de fora da curva, em ambos os pontos analisados.

The authors analyzed the wear in apical third after K3 .04 System preparation. 12 sets of instruments were used and 12 simulated canals in transparent epoxy resin blocks with angles of curvature 20 and 40 degrees. Canals were photographed before preparation and after the utilization of instruments which prepared the apical stop: 30, 35, 40 e 45. The images were overposed inAdobe Photoshop program and the wear was measured in millimeters, in two points, 1 (A) and 5 (B) millimeters from the working length. By Variance Analysis the interaction existencewas studied among these three factors: canal curvature, instrument caliber and curve location. In canals of 20 degrees, in both analyzed points, the wear mean promoted by instrument 40 and instrument 35 there was not statistically signifi cant. In canals of 40 degrees, in location A, there was not statistically signifi cant difference in the wear mean promoted by four differentinstruments. There was a deviation from the original trajectory to the outside the curve, in both analyzed points.

Wear promoted in the apical third of simulated canals after instrumentation with ProTaper universal system.

OBJECTIVE: This study evaluated the wear in the apical third of simulate canals after preparation with ProTaper Universal Rotary System. MATERIAL AND METHODS: 24 sets of instruments were used in 24 simulated canals in transparent epoxy resin blocks with degree of curvature of either 20 degrees or 40 degrees. The canals were photographed preoperatively and after preparation of the apical stop with ProTaper F3, F4 and F5 instruments. The initial and final images were exported to Adobe Photoshop software and superimposed to detect the root canal wall differences (in mm) between them, in two points located 1 (A) and 5 (B) mm from the point where the working length was established. Data were subjected to analysis of variance to verify the existence of interaction among the factors: canal curvature, instrument size and curve location. Significant level was set at 5%. RESULTS: Regardless of the location and the canal curvature, F4 and F5 instruments produced the greatest wear (p<0.05). CONCLUSIONS: There was a deviation from the original pathway towards the outside of the root curvature in both analyzed points. All instruments produced canal transportation, but the F4 and F5 instruments produced more than the other instruments, and should thus be used with care in curved canals.

Wear promoted in the apical third of simulated canals after instrumentation with protaper universal system

OBJECTIVE: This study evaluated the wear in the apical third of simulate canals after preparation with ProTaper Universal Rotary System. MATERIAL AND METHODS: 24 sets of instruments were used in 24 simulated canals in transparent epoxy resin blocks with degree of curvature of either 20°or 40°. The canals were photographed preoperatively and after preparation of the apical stop with ProTaper F3, F4 and F5 instruments. The initial and final images were exported to Adobe Photoshop® software and superimposed to detect the root canal wall differences (in mm) between them, in two points located 1 (A) and 5 (B) mm from the point where the working length was established. Data were subjected to analysis of variance to verify the existence of interaction among the factors: canal curvature, instrument size and curve location. Significant level was set at 5 percent. RESULTS: Regardless of the location and the canal curvature, F4 and F5 instruments produced the greatest wear (p<0.05). CONCLUSIONS: There was a deviation from the original pathway towards the outside of the root curvature in both analyzed points. All instruments produced canal transportation, but the F4 and F5 instruments produced more than the other instruments, and should thus be used with care in curved canals.

Avaliação da acurácia de três diferentes marcas comerciais de réguas calibradoras de cones de guta-percha / Evaluation of the accuracy of three different calibration rules trademarks for gutta-percha points

Introdução e Objetivo: O objetivo do presente estudo foi avaliar o padrão de estandardização dos tamanhos dos orifícios 35, 50 e 140 de três diferentes marcas comerciais de réguas calibradoras de cones de guta-percha e verificar possíveis distorções nos diâmetros 0,35; 0,50 e 1,40 mm após quatro ciclos de esterilização. Material e métodos: Foram fotografadas 10 réguas de cada uma das seguintes marcas comerciais: Angelus®, Maillefer® e Prisma®. Nove réguas (três de cada marca) foram submetidas a quatro ciclos de esterilização e fotografadas após cada um deles. Resultados e conclusão: Os resultados mostraram que houve variação nos diâmetros dos orifícios após as esterilizações, e que as três marcas apresentaram falta de fidelidade ao tamanho mencionado pelos fabricantes quando novas, isto é, sem esterilizações. A marca Maillefer®, antes de esterilizada, foi a que apresentou maior acurácia.

Introduction and Objective: The purpose of this study was to evaluate the standardization`s pattern of the holes of 3 different calibration rules trademarks for gutta-percha points and to verify possible distortions in the 0,35, 0,50 and 1,40mm diameters after four repeated cycles of sterilization. Material and methods: They were photographed 10 rules of each trademarks: Angelus®, Maillefer® and Prisma®. Nine rules (three of each brand) were subjected to 4 sterilization`s cycles and then photographed after each one. Results and conclusion: The results showed that there was variation in the holes`s diameter after the sterilization, and that the three brand new rules showed lack of loyalty to the size specified by the manufacturers. Maillefer® showed the greatest accuracy.

Verificação da trajetória angular percorrida por três peças automatizadas de movimento oscilatório / Verification of the traveled angular path for the oscillatory movements of three automated pieces

Para a realização deste estudo selecionou-se três peças automatizadas: M4 (Kerr Corporation), Endo-Gripper (Moyco Union Broach) e NSK TEP-E10R (Adiel Super Endo), todas com, aproximadamente, um ano de uso. Utilizou-se para os testes as velocidades de 6000, 8000 e 10000 rpm, verificando-se suas repercussões na trajetória angular dos sistemas. O registro do traçado das angulagens executadas foi obtido através da integração de um aparato constituído de lima endodôntica, haste plástica e grafite, adaptados, em cada peça automatizada, de maneira que a extremidade do grafite ficasse em contato com uma folha de papel milimetrado. Os resultados obtidos, após análise estatística, demonstraram que nenhuma das peças automatizadas testadas, independente da velocidade empregada, descreve a angulagem indicada pelo fabricante, ou seja, 45º para o Endo-Gripper e o Tep 10R (NSK), e 30º para o M4, num percurso total de 90º e 60º, respectivamente, e que a trajetória dos movimentos oscilatórios estava vinculada ao próprio sistema e velocidade empregados.

For accomplishment of this study, three automated pieces were selected: M4 (Kerr Corporation), Endo-Gripper (Moyco Union Broach) and NSK TEP-E10R (Adiel Super Endo), allwith nearly one year of use. Tests were performed at speeds of 6000, 8000 and 10000 rpm, with observation of their infl uence on the angular pathway of the systems. Recording of the tracing ofangles was achieved by integration of an apparatus comprising endodontic fi le, plastic rod and graphite, connected to the automated handpiece, so as the end of the graphite was in contact with amillimeter paper. After statistical analysis, the results achieved revealed that none of the automated pathway indicated by the manufacturer, i.e 45º for Endo-Gripper an NSK, and 30º for M4, having a total pathway of 90º and 60º, respectively; moreover, the pathway of oscillating movements wasrelated to the system and speed employed.

Cirurgia paraendodôntica: relato de caso clínico / Paraendodontic surgery: case report

Introdução: A cirurgia paraendodôntica é um procedimento que tem como finalidade resolver problemas que não puderam ser solucionados pelo tratamento endodôntico convencional, ou quando este não é possível. Relato do caso e conclusão: Neste trabalho há o relato de um caso clínico de dentes portadores de coroas protéticas com pinos intra-radiculares, em que se optou pela realização do procedimento cirúrgico. Foram efetuadas apicectomia e retroobturação com MTA no dente 11, apicectomia no dente 21 e apicectomia, retroinstrumentação e retrobturação com MTA no dente 22.

Introduction: Paraendodontic surgery is a procedure that aims problems resolution that couldn’t be solved by the conventional endodontic treatment, or when the accomplishment conventional treatment is not possible. Case report and conclusion: The aim of this study was to report a clinical case where was made apicectomy on the teeth 11, 21 and 22. The tooth 22 was sealing of root-end cavity MTA retrofilling.

Capacidade de abaixamento de temperatura da superfície interna da câmara pulpar após a aplicação do gás refrigerante à base de tetrafluoretano em dente extraído hígido e restaurado / Ability to decrease the temperature in the pulp chamber?s internal surface after the application of tetrafluorethane freezing gas on sound and restored extracted tooth

O sucesso do tratamento endodôntico está relacionado diretamente a um correto diagnóstico. Entre os recursos semiotécnicos empregados em Endodontia, o teste de vitalidade pulpar com gás refrigerante constitui auxílio clínico destinado a despertar resposta da polpa. Existem dificuldades de interpretação das respostas sensoriais em dentes portadores de restaurações, que podem agir como condutoras ou isolantes térmicos, diminuindo a acurácia do teste semiotécnico. Por isso, este estudo teve como intuito avaliar em um dente canino superior humano extraído a capacidade de abaixamento de temperatura da superfície interna da câmara pulpar após a aplicação do gás refrigerante à base de tetrafluoretano em três diferentes situações clínicas. No dente inicialmente hígido, posteriormente quando restaurado com amálgama e, finalmente, quando removida a restauração de amálgama e restaurado com resina composta. Quando o teste envolveu o dente restaurado com amálgama, o grau de abaixamento de temperatura foi maior, estatisticamente significativo, em relação às outras duas situações. No que concerne ao do tempo necessário para atingir a temperatura mínima, não existiram diferenças estatísticas significantes entre o dente hígido e o dente com amálgama, também não houve diferenças estatísticas entre o dente hígido e o dente com resina. Entretanto, o dente restaurado com resina e o dente restaurado com amálgama são diferentes estatisticamente. O amálgama foi o material que oportunizou o menor tempo para chegar à temperatura mais baixa. Ao executar um teste semiotécnico com spray refrigerante, o tempo e a intensidade das respostas dolorosas podem variar quando existe algum material a ser transposto na superfície dentária.

The successfull endodontic treatment is connected to a correct diagnostic. Amongst the most commonly diagnosis methods used in endodontics, the pulpal vitality test constitutes a clinical aid to evoke a response from the pulp. There are interpretation difficulties about sensitive responses on restored teeth. The restorations may be thermic conductors or insulators, reducing the accuracy of pulpal vitality test. Thus, the aim of this study was to verify the capacity to decrease the temperature pulp chamber?s inside surface after the application of tetrafluorethane freezing gas on upper extracted human canine tooth in three clinical situations: with sound tooth, when the tooth was restored with amalgam and when the tooth was restored with composite resin. When the test involved the tooth restored with amalgam the temperature reduction was statistically higher than the sound tooth and the restored tooth with composite resin. About the time taken to reach the minimal temperature there were no statistically significant differences between the healty tooth and the tooth restored with amalgam. There were again no differences between the sound tooth and the tooth restored with composite resin. However, the tooth restored with composite resin and the tooth restored with amalgam are statistically different. Amalgam was the material which required less time to get to the minimal temperature. Time and intensity of sensitive responses may be changed when there is a restored material on dental surface.

Injeção acidental de hipoclorito de sódio na região periapical durante tratamento endodôntico: relato de caso / Accidental injection of sodium hypochlorite in periapical region during endodontic treatment: case report

A finalidade deste trabalho foi relatar um caso clínico em que ocorreu a injeção acidental na região periapical da solução irrigadora de hipoclorito de sódio 2,5% durante tratamento endodôntico de um primeiro molar superior. Os autores demonstraram, por meio da descrição deste caso clínico, que soluções concentradas de hipoclorito de sódio, quando extrudadas inadvertidamente para a região periapical, causam danos teciduais, desconforto para o paciente e, consequentemente, dúvidas quanto à habilidade do cirurgião-dentista

The authors' aim was to report a clinical case of accidental injection of sodium hypochlorite 2,5% into periapical region during the root canal treatment of the upper right first molar. It was demonstrated that sodium hypochlorite concentrate solutions injection induces tissular injuries, discomfort for the patient and doubts about the dentist's ability