Influência da técnica de preparo apical na desinfecção e modelagem dos canais radiculares: revisão de literatura / Influence of apical preparation technique on root canal disinfection and shaping: literature review

Introdução: um dos objetivos da terapia endodôntica é a redução dos fatores microbianos no interior dos canais radiculares, o que pode ser conseguido por meio do preparo químico-mecânico (PQM). O PQM tem como finalidade criar um ambiente propício à condição de reparo, por meio da limpeza e modelagem do sistema de canais radiculares (SCR), que associa a ação mecânica dos instrumentos ao uso de substâncias químicas auxiliares. Em relação ao limite apical desse preparo e ao diâmetro apical final da instrumentação, podemos observar que não há consenso entre os profissionais. Introdução: o objetivo do presente estudo foi avaliar, por meio de uma revisão de literatura, a eficiência de duas técnicas no preparo e desinfecção do terço apical do SCR: a técnica de ampliação foraminal e a técnica de batente apical com manutenção da patência foraminal. Métodos: foi realizada uma busca nas bases de dados PubMed, Medline, BBO, Lilacs e SciELO, usando os seguintes termos: canal radicular, forame apical, endodontia, lima de patência, tamanho apical, lima apical final, preparo biomecânico, ampliação foraminal, comprimento de trabalho, anatomia dental, tratamento endodôntico, patência foraminal, preparo do canal radicular e batente apical. Cada um desses termos foi combinado utilizando os operadores booleanos E/OU. Após leitura dos resumos, 65 artigos foram selecionados e incluídos nessa revisão. Resultados: os resultados demonstraram que o alargamento do terço apical, seja com ou sem ampliação foraminal, parece favorecer o prognóstico do tratamento endodôntico, devido à redução do conteúdo infeccioso em toda a extensão do SCR. A manutenção da patência foraminal é um fator essencial para um PQM adequado quando a técnica de batente apical é realizada. Conclusão: conclui-se que preparos apicais mais amplos promovem resultados mais previsíveis, e que a ampliação foraminal possibilita o melhor debridamento e desinfeção do SCR (AU).

Introduction: Endodontic therapy should reduce the microbial load within the root canals, which can be achieved during chemomechanical preparation (CMP). The purpose of CMP of the root canal system (RCS) is to create a favorable environment for healing. CMP associates the mechanical action of instruments with the use of auxiliary chemical substances. There is no consensus among professionals about what should be the diameter of the apical foramen after CMP. This literature review evaluated the efficiency of two apical preparation techniques: foraminal enlargement and apical stop with maintenance of foraminal patency. Material and methods: A literature search was conducted in PubMed, Medline, BBO, Lilacs and Scielo using the following terms: root canal, apical foramen, endodontics, patency file, apical size, master apical file, biomechanical preparation, foraminal enlargement, working length, dental anatomy, endodontic treatment, foraminal patency, root canal preparation, and apical stop. All terms were combined using the Boolean operators AND/OR. After the abstracts were analyzed, 65 full texts were selected and included in this review. Results: The enlargement of the apical third, with or without foraminal enlargement, seems to improve endodontic treatment prognosis due to the reduction of infectious contents throughout the RCS. Foraminal patency is essential for adequateCMP when the apical stop technique is performed. Conclusion: Apical preparations with a greater diameter have more predictable results, and foraminal enlargement ensures better debridement and disinfection of the RCS (AU).

Effect of Intermediate Flush Using Different Devices to Prevent Chemical Smear Layer Formation

Abstract This study compared the effect of intermediate flush with distilled water delivered by conventional irrigation, EndoVac microcannula or Self-Adjusting File (SAF) system in the prevention of chemical smear layer (CSL) formation. Thirty human premolars were used. Canals were prepared with Reciproc system and 5.25% NaOCl. After chemomechanical preparation, samples were divided in 3 groups (n=10) according to the intermediate irrigation protocol with distilled water using: conventional irrigation, EndoVac microcannula or SAF. A final flush with 2% chlorhexidine solution was used and scanning electron microscopy was performed to assess protocol effectiveness. Two calibrated evaluators attributed scores according the presence or absence of CSL on the surface of the root canal walls at the coronal, middle and apical thirds, as follows: (1) no CSL; (2) small amounts of CSL; (3) moderate CSL; and (4) heavy CSL. Differences between protocols were analyzed with Kruskal-Wallis and Mann-Whitney U tests. Friedman and Wilcoxon signed rank tests were used for comparison between each root canal third. SAF resulted in less formation of CSL when compared with the conventional irrigation and EndoVac microcannula (p<0.05). When root canal thirds were analyzed, conventional irrigation and EndoVac groups showed less CSL formation at coronal and middle thirds in comparison to the apical third (p<0.05). In SAF group, there was no difference among the thirds (p>0.05). It may be concluded that an intermediate flush of distilled water, delivered by the SAF system resulted in a better reduction of CSL formation during chemomechanical preparation.

Resumo O presente estudo comparou o efeito da utilização de uma irrigação intermediária com água destilada usando a irrigação convencional, a microcânula EndoVac ou o sistema Self-Adjusting File (SAF) na prevenção de formação da smear-layer química (SLQ). Trinta pré-molares humanos foram utilizados. Os canais foram preparados com sistema Reciproc e irrigados com NaOCl a 5,25%. Após o preparo químico mecânico, as amostras foram divididas em 3 grupos (n=10) de acordo com o protocolo de irrigação intermediária com água destilada utilizado: irrigação convencional, a microcânula EndoVac ou SAF. Utilizou-se uma lavagem final com solução de clorexidina a 2% e a microscopia electrónica de varredura foi utilizada para avaliar a eficácia dos protocolos. Dois avaliadores calibrados atribuíram escores de acordo com a presença ou ausência de SLQ nas paredes do canal radicular nos terços coronal, médio e apical, como a seguir: (1) sem SLQ; (2) pequenas quantidades de SLQ; (3) SLQ moderada e (4) muita SLQ. As diferenças entre protocolos foram analisadas com testes de Kruskal-Wallis e Mann-Whitney U. Os testes Friedman e Wilcoxon foram utilizados para comparação entre cada terço do canal radicular. SAF resultou em menor formação de SLQ quando comparado com a irrigação convencional e a microcânula EndoVac (p<0,05). Quando os terços dos canais radiculares foram analisados, os grupos irrigação convencional e microcânula EndoVac apresentaram menor formação de SLQ nos terços coronal e médio em relação ao terço apical (p<0,05). No grupo SAF, não houve diferença entre os terços (p>0,05). Dentro dos resultados do presente estudo, pode-se concluir que um fluxo intermediário de água destilada, administrado pelo sistema SAF resultou em melhor redução da formação de SLQ durante o preparo químico mecânico.

Antimicrobial activity and substantivity of Uncaria tomentosa in infected root canal dentin

Abstract The aim of this study was to analyze the antimicrobial activity and substantivity of Uncaria tomentosa Willd DC (cat's claw, CC) in root dentin contaminated with Enterococcus faecalis. Forty-eight human premolars were contaminated with E. faecalis (ATCC 29212) and randomly divided into four groups according to the irrigant used during chemomechanical preparation (CMP): CC group: 2% CC gel; CHX group: 2% chlorhexidine digluconate gel (CHX); NaOCl group: 5.25% sodium hypochlorite (NaOCl); and SS group: sterile saline (SS). Microbiological samples were collected before (S1) and after (S2) CMP and after 7 days (S3). Colony-forming units (CFU/mL) at the different sampling times and comparisons among the groups were statistically analyzed by Wilcoxon and Kruskal-Wallis tests (p < 0.05). Significant bacterial reduction was achieved in all groups after CMP (p < 0.05). Results show no significant difference between S3 and S2 (p > 0.05) in the CC and CHX groups. Bacterial load was higher in S3 than in S2 samples (p < 0.05) in the NaOCl and SS groups. Our results suggest antibacterial effect of 2% CC gel against E. faecalis in infected dentin, in addition to antibacterial substantivity of 2% CC and 2% CHX up to 7 days.

Effectiveness of nano-calcium phosphate paste on sensitivity during and after bleaching: a randomized clinical trial

The study aimed to evaluate the effectiveness of in-office bleaching and associated tooth sensitivity on application of nano-calcium phosphate paste as desensitizing agent. Bleaching was performed with 35% hydrogen peroxide gel in 40 patients who were randomly divided into placebo and nano-calcium phosphate paste groups. Bleaching efficacy (BE) was evaluated using a value-oriented Vita shade guide. Tooth sensitivity was recorded using a numeric rating scale (0–4) during bleaching and up to 48 h after each session. The primary outcome of absolute risk of tooth sensitivity was compared using the Fisher’s exact test (α = 0.05). The intensity of tooth sensitivity and the efficacy of in-office bleaching were also statistically evaluated. No significant differences in absolute risk and intensity of tooth sensitivity were detected between the groups (p = 1.0 and p = 0.53, respectively). BE was also found to be similar between the groups (p = 0.67). Although the use of a nano-calcium phosphate paste associated with fluoride and potassium nitrate did not influence the whitening outcome, but it also did not reduce bleaching-induced tooth sensitivity.

Effectiveness of rotatory and reciprocating movements in root canal filling material removal

The purpose of this study was to compare the efficacy of reciprocating and rotary techniques for removing gutta-percha and sealer from root canals. Forty straight and oval single-rooted premolars were prepared up to size 30, filled with gutta-percha and sealer, and then randomly allocated to two experimental retreatment groups: ProTaper Retreatment System (PTRS) and WaveOne System (WS). Procedural errors, time of retreatment and apically extruded material were recorded for all the roots. The roots were radiographed after retreatment. The percentage of residual material was calculated using image analysis software. The data were analyzed by Kolmogorov-Smirnov and t tests, with a significance level set at 5%. No system completely removed the root filling material from the root canal. No significant differences were observed between the systems, in terms of residual filling material in any tested third (p > 0.05). WS was faster in removing filling material than PTRS (p< 0.05). Extrusion was observed in 4 cases in PTRS and in 5 cases in WS. No procedural errors were observed in either group. It can be concluded that although no differences were observed in the efficacy of PTRS and WS for removing root filling material, WS was faster than PTRS.

Evaluation of cytotoxicity, antimicrobial activity and physicochemical properties of a calcium aluminate-based endodontic material

A calcium aluminate-based endodontic material, EndoBinder, has been developed in order to reduce MTA negative characteristics, preserving its biological properties and clinical applications. Objectives: The aim of this study was to evaluate the cytotoxicity, antimicrobial activity, pH, solubility and water sorption of EndoBinder and to compare them with those of white MTA (WMTA). Material and Methods: Cytotoxicity was assessed through a multiparametric analysis employing 3T3 cells. Antimicrobial activity against Enterococcus faecalis (ATCC 29212), Staphylococcus aureus. (ATCC 25923) and Candida albicans (ATCC 10556) was determined by the agar diffusion method. pH was measured at periods of 3, 24, 72 and 168 hours. Solubility and water sorption evaluation were performed following ISO requirements. Data were statistically analyzed by ANOVA and Tukey`s test with a significance level of 5%. Results: EndoBinder and WMTA were non-cytotoxic in all tested periods and with the different cell viability parameters. There was no statistical differences between both materials (P>.05). All tested materials were inhibitory by direct contact against all microbial strains tested. EndoBinder and WMTA presented alkaline pH in all tested times with higher values of pH for WMTA (P<.05). Both materials showed values complying with the solubility minimum requirements. However, EndoBinder showed lower solubility than WMTA (P<.05). No statistical differences were observed regarding water sorption (P>.05). Conclusion: Under these experimental conditions, we concluded that the calcium aluminate-based endodontic material EndoBinder demonstrated suitable biological and physicochemical properties, so it can be suggested as a material of choice in root resorption, perforations and root-end filling. .

Furcal-perforation repair with mineral trioxide aggregate: Two years follow-up.

Furcal perforations are significant iatrogenic complications of endodontic treatment and could lead to endodontic failure. Mineral trioxide aggregate (MTA) has been regarded as an ideal material for perforation repair, retrograde filling, pulp capping, and apexification. This case report describes a furcal perforation in a maxillary first molar, which was repaired using MTA. The tooth was endodontically treated and coronally restored with resin composite. After 2 years, the absence of periradicular radiolucent lesions, pain, and swelling along with functional tooth stability indicated a successful outcome of sealing the perforation using MTA.

Acuidade do Root ZX II utilizando limas de aço inoxidável e de níquel-titânio

Objetivo: avaliar in vitro a eficiência do localizador apical eletrônico (LAE) Root ZX II em determinar o comprimento de trabalho, utilizando limas manuais de aço inoxidável,limas manuais de níquel-titânio e limas rotatórias de níquel-titânio. Métodos: foram utilizados 20 dentes humanos unirradiculares (incisivos centrais retos). O comprimento real do dente (CRD) foi determinado através da inserção de um lima #15 até que a sua ponta fosse visível no forame apical, utilizando uma ampliação de 4x. A lima foi removida do canal e seu comprimento foi medido com um paquímetro digital. Para as medições eletrônicas,as amostras foram fixadas em uma embalagem de vidro com cobertura plástica, contendo solução salina a 0,9%. As medições foram realizadas utilizando-se o Root ZX II, com lima #15 de aço inoxidável, lima manual de níquel-titânio e lima rotatória Mtwo. As limas foram acopladas ao LAE e as medições foram monitoradas até que o LAE indicasse o valor “zero”. Os valores correspondentes à diferença entre o CRD e a medição eletrônica foram gravados e submetidos à análise de variância(ANOVA) e o teste Tukey (α=0,05). Resultados: não houve diferença estatisticamente significativa (p<0,05)entre as limas testadas. Conclusão: a partir do presente estudo, constatou-se que o LAE Root ZX II foi eficaz,mostrando-se um método confiável, e que nenhuma interferência significativa na sua leitura foi detectada ao se utilizar as diferentes limas

Utilização da fita de politetrafluoretileno como matriz em odontologia restauradora: relato de caso clínico / The use of the polytetrafluorethylene tape as matrix in operative dentistry: a clinical report

O objetivo deste relato de caso clínico é apresentar a utilização da fita de politetrafluoretileno (PTFE) para facilitar a técnica de reprodução anatômica durante a restauração de incisivos centrais superiores. Paciente do sexo feminino, 10 anos de idade, apresentou-se na Clínica de Dentística Operatória e Estética da Universidade Peruana Cayetano Heredia - UPCH, para a realização de restaurações nos dentes 21 e 11. Os dentes foram preparados, de acordo com as técnicas convencionais. Em seguida, os dentes adjacentes foram secos e recobertos com um pedaço de fita de PTFE. Os dentes foram, então, restaurados, utilizando-se uma resina composta de nanopartículas, por meio das técnicas da matriz de silicone e da técnica incremental. No final da restauração, a fita de PTFE foi removida e procederam-se o acabamento e o polimento das restaurações. Após o término da restauração, uma aparência estética e natural do dente fraturado foi conseguida, satisfazendo as expectativas funcionais e estéticas do paciente.

The aim of this case report is to present the use of PTFE tape to make easier the copy of anatomic details, during the restoration of maxillary central incisors. A 10-year-old girl attended the Dental Clinic of the Universidad Peruana Cayetano Heredia - UPCH with fracture in the teeth 21 and 11. The teeth were prepared, in according to conventional techniques. Next, the adjacent teeth were dry and covered with a piece of tape of PTFE. The teeth were restored using a composite resin of nanoparticles, through the techniques of the silicon matrix and composite stratification. When the restoration was finished, the tape of PTFE was removed and the finishing and polishing of the restorations were made. After the restoration, an aesthetic and natural appearance of toothfracture was achieved, satisfying the expectations and functions of the patient.