A opção pelo retratamento não cirúrgico na presença de pinos intrarradiculares: riscos e benefícios / The option for nonsurgical retreatment in the presence of intraradicular posts: risks and benefits

Introdução: O retratamento não cirúrgico é uma opção de tratamento quando ocorre o insucesso no tratamento endodôntico, porém, em muitos casos, há necessidade da remoção prévia de pinos intrarradiculares. Objetivo: Esta revisão de literatura tem como objetivo citar os riscos e os benefícios da opção pelo retratamento endodôntico não cirúrgico na presença de pinos intrarradiculares, bem como citar materiais e técnicas para a remoção de diferentes tipos de pinos. Conclusão: A opção pelo retratamento endodôntico não cirúrgico, em casos em que há necessidade de remoção de pinos, é segura e de índice de sucesso considerável, por isso, deve-se levar em conta o conhecimento de técnicas e os fatores que podem influenciar durante o processo, a fim de prevenir acidentes, bem como saber que apenas a presença do pino intrarradicular não é indicação para o tratamento cirúrgico.

Introduction: Nonsurgical retreatment is a treatment option when the failure happens in the endodontic treatment, but in many cases, there is need for prior removal intrarradicular posts. Objectives: This literature review aims to cite the risks and benefits of option for nonsurgical endodontic retreatment in the presence of intraradicular posts and cite materials and techniques for removing different types of posts. Conclusion: The option for nonsurgical endodontic retreatment in cases where removal the posts there need, is safe and considerable success rate, therefore, one should take into account the knowledge of techniques and factors that may influence during the process, in order to prevent accidents, as well as to know that only the presence of intraradicular post is no indication for surgical treatment.

Influence of solvents on the bond strength of resin sealer to intraradicular dentin after retreatment

Abstract This study evaluated the removal of filling material with ProTaper Universal Rotary Retreatment system (PTR) combined with solvents and the influence of solvents on the bond strength (PBS) of sealer to intraradicular dentin after canal reobturation. Roots were endodontically treated and distributed to five groups (n = 12). The control group was not retreated. In the four experimental groups, canals were retreated with PTR alone or in combination with xylol, orange oil, and eucalyptol. After filling material removal, two specimens of each group were analysed by SEM and µCT to verify the presence of filling remnants on root canal walls. The other roots were reobturated and sectioned in 1-mm-thick dentin slices that were subjected to the push-out test. Data were analysed by two-way ANOVA and Tukey’s test (α = 0.05). SEM and µCT analysis revealed that all retreatment techniques left filling remnants on canal walls. The control group (3.47 ± 1.21) presented significantly higher (p < 0.05) PBS than the experimental groups. The groups retreated with PTR alone (2.59 ± 0.99) or combined with xylol (2.54 ± 0.77) and orange oil (2.32 ± 0.93) presented similar bond strength (p > 0.05), and differed significantly from the group with eucalyptol (1.89 ± 0.63). The solvents reduced the PBS of the sealer to dentin and no retreatment technique promoted complete removal of filling material.

Comparison of two methods of irrigant agitation in the removal of residual filling material in retreatment

Abstract: The aim of this study was to compare the efficacy of passive ultrasonic irrigation and EasyClean for removing residual filling material in retreatment. Twenty-two maxillary lateral incisors with apical curvature were instrumented with ProTaper files and filled with Endofill using the lateral compactation technique. Removal of filling material was performed with Reciproc, Mtwo and ProDesign Logic 50/.01 files. The teeth were inserted in a silicone mould, which was placed in a metal muffle, and split to visualize the residual filling material. The samples were divided into two groups (n = 11) according to the irrigation protocol: Passive ultrasonic irrigation (PUI group) with 3 activations of 20 seconds and EasyClean (Easy Equipamentos Odontológicos, Belo Horizonte, Brazil) (EC group) used in continuous rotation with 3 activations of 20 seconds, both using NaOCl and EDTA. Environmental scanning electron microscopic images of the apical, middle, and cervical thirds were taken before and after the irrigant activation. The Kappa test was used to determine interexaminer agreement. Statistical analysis was performed using Kruskal-Wallis, Mann-Whitney, and Wilcoxon tests (p < 0.05). PUI and EC improved the removal of remnant filling material in all root canal thirds (p < 0.05). PUI and EC presented similar performance in the final step of retreatment (p > 0.05). No significant difference was observed in the removal of filling material in the apical, middle, and cervical thirds in both groups (p > 0.05). EasyClean in continuous rotary motion is useful in retreatment and was shown to be as effective as ultrasonic activation in the removal of remnant filling material.

Assessment of rotary and reciprocating movements in root canal filling material removal / Análise dos sistemas rotatórios e reciprocante com diferentes ligas na desobturação em retratamento endodônticos

The aim of this study was to evaluate the effects of preparation, filling removal material, reinstrumentation and reobturation of root canals with different Ni-Ti alloys in endodontic retreatment. Firstly, the selection and pairing of mesial root canals of mandibular molars (n = 45) were performed by computerized micro-tomography (micro-CT). After pairing, the specimens were divided into three groups (n = 15), instrumented with the Mtwo® (up to file 25.06), ProDesign Logic (25.06) and ProDesign R (25.06) systems. After this, the specimens were scanned again for root canal deviation analysis at 2, 4, 6, 8 and 10 mm from the apex and the volume increase of these root canals was evaluated through CTan Then, the root canals were filled with Endofill® with 0.1% rhodamine B and scanned in micro-CT once again. For the retreatment of the specimens, 3 groups were established according to the system used (Reciproc®, Hyflex® and ProDesign Duo Hybrid®). During the retreatment, the specimens were scanned in micro-CT in two more phases, after removal of filling material and after reinstrumentation of the root canals. All the images obtained previous and post-retreatment were compared to evaluate the capacity of removal filling material of each system through the volume of material remaining at 3mm in the apical third. Possible deviation of the root canal was assessed at 2, 4, 6, 8 and 10 mm from the apex. In addition, the times of preparation, removal filling material and reinstrumentation of these files were also evaluated. After the removal filling material and reinstrumentation of the root canals, they were refilled with AH Plus with 0.1% fluorescein. The specimens were sectioned crosswise into 2 mm slices to be analyzed by a confocal laser scanning microscope (CLSM) at 1, 3 and 5 mm from the apex, where the volume of material was evaluated through LAS X 3D and 2D software. The time of preparation, removal filling material and reinstrumentation of the root canals between the different systems was measured by a digital timer. The evaluation of canal volumetric increase and preparation time between Mtwo and ProDesign Logic systems were conducted using Student t-test analysis. Non-parametric Wilcoxon test was used to the intragroup comparison at the 2, 4, 6, 8 and 10 mm levels and non-parametric Mann-Whitney test was used to the comparison between groups in the root canal transportation in all sections of the root canal. The intra-group comparison regarding the presence or absence of root canal deviation after removal of root canal filling material and re-instrumentation was submitted to the parametric T-paired statistical test, since it had a normal distribution. The working time with the different alloys used to removal filling material an reinstrumentation was analyzed through parametric ANOVA e Tukey statistical test. The analysis of the remaining material present in the root canals was performed with nonparametric Kruskal-Wallis and Dunn tests. For the intra-group comparison between the different slices (1, 3 and 5 mm), the data were submitted to nonparametric Friedman and Dunn tests. The level of significance was established at 5% in all analysis. After the initial preparation of the root canals, the ProDesign Logic system proved to be faster than Mtwo system, with statistical difference between them (P <0.05). There was no statistical difference in root canal deviation after initial preparation and after retreatment (P> 0.05). In addition, the groups did not present a significant statistical difference to the volume increase of the root canals after the initial preparation or to the volume of filling material remaining after the retreatment (P> 0.05). The Reciproc system proved to be the fastest system for the removal filling material and reinstrumentation of the root canals (P <0.05). The present study demonstrated that the Prodesign Logic and Mtwo systems presented similar capacity of preparation of mesial root canals. The Reciproc, Hyflex and ProDesign Duo Hybrid systems are similar in the removal of filling material, preserving the original root canal shape in endodontic retreatment. However, Reciproc was the fastest compared to the other groups.(AU)

O presente trabalho teve como objetivo avaliar os efeitos decorrentes do preparo inicial, desobturação, reinstrumentação e reobturação de canais radiculares com diferentes ligas de Ni-Ti em casos de retratamento endodôntico. Primeiramente, foi realizado a seleção e o pareamento da anatomia de canais mesiais de primeiros molares inferiores (n=45) através de micro-tomografia computadorizada (micro-CT). Após o pareamento dos espécimes, os mesmos foram divididos em três grupos (n =15), instrumentados com os sistemas Mtwo® (até a lima 25.06), ProDesign Logic (25.06) e ProDesign R (25.06) sendo escaneados novamente para análise de desvio do canal radicular a 2, 4, 6, 8 e 10 mm, além do aumento de volume desses canais, avaliados através do CTan. Em seguida, os canais radiculares foram obturados com o cimento Endofill® acrescido de 0,1% de rodamina B e escaneados em micro-CT mais uma vez. Para o retratamento dos espécimes, foram estabelecidos 3 grupos, de acordo com o sistema utilizado (Reciproc®, Hyflex® e ProDesign Duo Híbrido®). Durante o retratamento, os espécimes foram escaneados em micro-CT em mais duas etapas, após a desobturação e a após a reinstrumentação dos canais. Todas as imagens obtidas referentes ao pré e pós retratamento foram confrontadas com o intuito de avaliar a capacidade de remoção de material obturador de cada sistema através do volume de material remanescente nos 3 mm apicais, além de avaliar possíveis desvios dos canais a 2, 4, 6, 8 e 10 mm do ápice. Foram avaliados também, o tempo efetivo de preparo, desobturação e de reinstrumentação desses instrumentos. Após a desobturação e reinstrumentação dos canais, os mesmos foram reobturados com cimento AH Plus acrescido de 0,1% de fluoresceína. Os espécimes foram seccionados transversalmente em fatias de 2 mm para serem analisados em microscópio confocal de varredura a laser (MCVL) a 1, 3 e 5 mm do ápice, onde foi avaliado, através do software LAS X 3D e 2D, o volume de material obturador antigo. O tempo de preparo, desobturação e reinstrumentação dos canais entre os diferentes sistemas foi marcado através de um cronômetro digital. A análise do aumento volumétrico e tempo de preparo entre os sistemas Mtwo e ProDesign Logic foi feita através do teste estatístico Student t. Para a análise do desvio do canal radicular após o preparo inicial, o teste não-paramétrico Wilcoxon foi utilizado para a comparação intra-grupos nos níveis a 2, 4, 6, 8 e 10 mm do ápice, enquanto o teste não-paramétrico Mann-Whitney foi utilizado para comparação entre os grupos nos mesmos níveis. Para a análise do desvio do canal radicular após a desobturação e reinstrumentação dos canais, os dados foram submetidos ao teste paramétrico T-pareado. O tempo de desobturação e reinstrumentação com os diferentes sistemas foi analisado através do teste ANOVA e Tukey. Os dados referentes ao remanescente de material obturador foram analisados através dos testes não-paramétrico Kruskal-Wallis e Dunn. Para a comparação intra-grupos entre os diferentes níveis (1, 3 e 5 mm) foram utilizados os testes não-paramétricos Friedman e Dunn. O nível de significância foi estabelecido a 5% em todas as análises. Após o preparo inicial dos canais, o sistema ProDesign Logic demonstrou ser mais rápido que o sistema Mtwo, havendo diferença estatística entre eles (P < 0.05). Não houve diferença estatística quanto ao desvio do canal radicular tanto após o preparo inicial quanto após o retratamento (P > 0.05). Além disso, os grupos também não apresentaram diferença estatística significante quanto ao aumento do volume dos canais após o preparo inicial, nem em relação ao volume de remanescente de material obturador após o retratamento (P > 0.05). O sistema Reciproc demonstrou ser o mais rápido dentre os sistemas quanto à desobturação e reinstrumentação dos canais (P < 0.05). O presente trabalho demonstrou que os sistemas Prodesign Logic and Mtwo apresentaram capacidade similar de preparo dos canais mesiais de molares inferiores. Os sistemas Reciproc, Hyflex e ProDesign Duo Híbrido são parecidos quanto à remoção de material obturador, preservando o formato original do canal em casos de retratamentos entodônticos. Entretanto, Reciproc foi o mais rápido comparado aos outros grupos.(AU)

Retrieval of multiple separated endodontic instruments using ultrasonic vibration: Case report

This report describes the management of a complicated clinical case with three instruments fractured in one tooth. A 32-year-old patient presented with three Pro- Taper rotary files fractured in the upper right second molar [S2 and F2 in the disto-buccal canal and S1 in the mesio-buccal canal]. A staging platform was prepared in the distal canal coronal to the fragments. Under dental microscope magnification, an Endo-4 ultrasonic tip was activated to dislodge the more coronal fragment [S2] by trephining dentine around the coronal aspect of the fragment. After 11 min, the fragment became loose and was removed. Following the same protocol and using an Endo-5 ultrasonic tip, the second fragment [F2] was removed in approximately 17 min. The first attempt to remove the S1 fragment from the mesio-buccal canal was not successful. An attempt to bypass this fragment using a K-file also failed. A second attempt using the ultrasonic technique resulted in a secondary fracture of the coronal aspect of the fragment. An Endo-5 ultrasonic tip was used to dislodge the fragment, which was successfully removed in 7 min. This report concludes that once a fractured file is bypassed, the instrumentation of a root canal is best completed with hand files. Clinicians should identify their limitations and consider referring cases that are beyond their abilities. Good experience and an appropriate armamentarium enable successful management of complicated cases. Ultrasonic vibration and dental microscope magnification contribute to successful removal of fractured instruments

Comparación de la capacidad de limpieza de tres sistemas rotatorios para la desobturación y retratamiento de conductos radiculares / Comparison of the cleaning ability of three rotary systems for the removal of filling materials in endodontic retreatment

El éxito de la reendodoncia está basado en gran parte en la correcta limpieza y preparación del sistema de conductos radiculares. Esto implica la eliminación de la obturación anterior y el remodelado del conducto. El material de obturación que queda en el conducto puede involucrar microorganismos y dentina infectada que comprometen el pronóstico del tratamiento. En este trabajo se comparó in vitro la eficacia de los sistemas ProTaper Universal Retratamiento (Dentsply Maillefer), D-RaCe Retratamiento (FKG) y Mtwo Retratamiento (VDW) para la remoción de conos de gutapercha y sellador. El sistema que dejó mayor residuo fue RaCe. De los otros dos sistemas, Mtwo tuvo el mejor desempeño,pero no llegó a presentar diferencias estadísticamente significativas con ProTaper. Mtwo logró una limpieza del 79,03 por ciento, seguido por el ProTaper con el 75,94 por ciento y RaCe con el 49,01 por ciento. La eliminación completa de la obturación endodóntica no se logró con ninguno de los sistemas de instrumentos investigados...

Comparison of debris extruded apically and working time used by ProTaper Universal rotary and ProTaper retreatment system during gutta-percha removal

OBJECTIVE: The aim of this study was to evaluate the in vitro action of ProTaper retreatment files and ProTaper Universal in the retreatment of mandibular premolars. MATERIAL AND METHODS: The amount of debris extruded apically was measured and the time to reach the working length and to complete the removal of gutta-percha was observed. Thirty teeth had their canals prepared using ProTaper Universal files and were obturated by the single cone technique. The teeth were then stored at 37ºC in a humid environment for 7 days. During the use of the rotary instruments for root canal filling removal, the apical portions of the teeth were attached to the open end of a resin tube to collect the apically extruded debris. RESULTS: ProTaper Universal files were significantly faster (p=0.0011) than the ProTaper retreatment files to perform gutta-percha removal, but no significant difference was found between the files regarding the time to reach the working length or the amount of apical extrusion. CONCLUSIONS: ProTaper Universal rotary had better results for endodontic retreatment, and both techniques promote similar apical extrusion of debris.

Análise comparativa de dois aparelhos ultra-sônicos na remoção de pinos intraradiculares / Comparative analysis of two ultrasonic instruments for intraradicular post removal

A remoção de pino intraradicular pode dificultar o retratamento endodôntico. O método ultra-sônico é considerado o mais conservador, pois permite a preservação da estrutura dental remanescente. Os aparelhos ultra-sônicos Enac (Osada Eletric CO., Japão) e Jet Sonic Four Plus (Gnatus, Ribeirão Preto, São Paulo, Brasil), ambos com efeito piezoelétrico foram avaliados pela sua eficácia. Dentes humanos incisivos e caninos extraídos foram tratados endodonticamente e receberam pinos pré-fabricados Unimetric (Dentsply/Maillefer, Suiça), fixados com cimento resinoso autopolimerizável (Jeneric/Penton, ISA). O tempo gasto para a remoção de cada pino foi cronometrado. O Enac apresentou um tempo médio de 4,33 minutos para incisivos e 7,08 minutos para caninos (p>0,05) e o Jet Sonic Four Plus, um tempo médio de 3,86 minutos para incisivos e 6,54 minutos para caninos (p>0,05). Concluiu-se que os dois aparelhos ultra-sônicos testados foram eficazes na remoção de pinos, sem a necessidade de métodos adicionais, e nenhuma diferença estatisticamente significante foi observada.