Influence of Passive Ultrasonic Irrigation on the Removal of Root Canal Filling Material in Straight Root Canals.

OBJECTIVE: This study evaluates the efficacy of passive ultrasonic irrigation (PUI) in removing root canal filling material from endodontically treated teeth after using one of two reciprocating systems, Reciproc (VDW, Munich, Germany) or WaveOne (Dentsply Maillefer, Ballaigues, Switzerland), or one nickel-titanium (NiTi) rotary system, ProTaper Universal Retreatment (Dentsply Maillefer). METHODS: One hundred and twenty straight root canals of extracted human maxillary incisors were instrumented and then obturated. The specimens were divided into six groups (n=20) as follows: Group R, Reciproc R25 instrument without PUI; Group W, WaveOne Primary instrument without PUI; Group PT, ProTaper Universal Retreatment system without PUI; Group R-PUI, Reciproc R25 with PUI; Group W-PUI, WaveOne Primary with PUI and Group PT-PUI, ProTaper Universal Retreatment system with PUI. After removing the filling material, the teeth were cleaved longitudinally and photographed. The total canal space and remaining material were quantified with the aid of an imaging software tool. The Kruskal-Wallis test was used to identify significant differences between the groups. RESULTS: No statistically significant differences (P>0.05) in residual filling material were observed between the groups. CONCLUSION: The use of PUI did not improve the removal of filling material from the root canals, regardless of the previously used instrumentation system.

Scouting Ability of 4 Pathfinding Instruments in Moderately Curved Molar Canals.

INTRODUCTION: Glide path preparation has been recommended as a mandatory clinical step to ensure the safe usage of nickel-titanium (NiTi) rotary instruments. This study aimed to evaluate the effectiveness and fracture rate of 4 pathfinding NiTi rotary instruments in mechanically negotiating moderately curved molar canals. METHODS: Moderately curved maxillary (n = 120) and mandibular (n = 120) molars were randomly distributed into 4 experimental groups (n = 60, 30 maxillary and 30 mandibular molars) according to the instrument used for glide path preparation: ScoutRace 10/.02 (FKG Dentaire, La Chaux-de-Fonds, Switzerland) (800 rpm and 1-Ncm torque), ProDesign 25/.01 (Easy Equipamentos Odontológicos, Belo Horizonte, MG, Brazil) (350 rpm and 1-Ncm torque), Mtwo 10/.04 (VDW, Munich, Germany) (280 rpm and 1.2 Ncm torque), or ProGlider 16/.02 (Dentsply Maillefer, Ballaigues, Switzerland) (300 rpm and 5-Ncm torque). The instrument fracture rate and the absolute and percentage frequencies of molars in which the pathfinding instruments reached the full working length in all root canals according to tooth and canal types were recorded and statistically compared using the Pearson's chi-square test (α = 5%). RESULTS: The highest and lowest frequency of reached the full working length canals were observed in the ScoutRace (68.3%) and ProDesign (38.3%) groups (P < .05), respectively, whereas the Mtwo (58.3%) and ProGlider (51.6%) groups showed intermediate results (P > .05). The ProGlider group showed the highest percentage frequency of instrument separation (11.6%) followed by the Mtwo (8.3%), ScoutRace (3.3%), and ProDesign (3.3%) groups (P < .05). CONCLUSIONS: ScoutRace performed more efficiently and with less instrument breakage than the other systems. ProDesign was the least efficient, and ProGlider exhibited the highest rate of instrument breakage among the systems tested.

The impact of endodontic irrigating solutions on the push-out shear bond strength of glass fiber posts luted with resin cements.

Resin-based restorative materials, widely used to cement posts, may be influenced by irrigants used during endodontic chemical-mechanical preparation. This study evaluated the impact of endodontic irrigating solutions and adhesive cement systems on the push-out shear bond strength of glass fiber posts to root dentin. Ninety-six bovine incisors were divided into 12 groups (4 irrigants × 3 resin cements; n = 8). Prepared canals were irrigated with saline solution, 2.5% sodium hypochlorite (NaOCl), 5.25% NaOCl, or 2% chlorhexidine gel, and posts were cemented with RelyX ARC, Panavia F, or RelyX U100. The bond strength was evaluated by means of the push-out test, and results were subjected to analysis of variance. The mean bond strength observed for the combination of 5.25% NaOCl irrigant and RelyX U100 cement was significantly lower (8.82 MPa) than the values found for the other groups (P < 0.05). The other combinations of irrigating solution and resin cement had no adverse effect on the bond strength of the glass fiber posts to dentin.

Comparação entre os sistemas rotatórios Pathfile + Protaper Universal e Twisted Files quanto à preservação da morfologia e ao tempo de trabalho despendido na preparação de canais curvos / Comparison of preparation time and ability to maintain canal morphology in curved canals: Pathfile + Protaper Universal versus Twisted Files

Introdução: Instrumentos rotatórios em níquel-titânio (NiTi) reduzem erros processuais e o tempo requerido para a preparação do canal radicular. Objetivo: Comparar dois sistemas de instrumentação rotatória NiTi - Pathfile + ProTaper Universal e Twisted Files - quanto à capacidade de preservação da morfologia do canal e quanto ao tempo de trabalho necessário para a preparação de canais curvos. Material e Método: Os canais mesiais de 32 molares inferiores humanos (com ângulos de curvatura entre 20 e 40 graus) foram selecionados para o estudo. As amostras foram divididas aleatoriamente em dois grupos de 16 canais. Os preparos foram realizados por um Endodontista, utilizando-se a combinação dos instrumentos rotatórios Pathfile e ProTaper Universal (grupo PT) e os instrumentos rotatórios Twisted Files (grupo TF). Três Endodontistas analisaram imagens com a técnica da dupla radiografia digital, pré e pós-instrumentação, para avaliar se ocorreu transporte apical e/ou aberrações na morfologia dos canais. Por meio de uma análise computadorizada e com o auxílio de magnificação, as imagens inicial e final do canal radicular foram comparadas por meio de sua sobreposição. O teste de odds ratio foi utilizado para a comparação dos níveis de preservação da morfologia do canal, e ANOVA, complementada pelo teste de Tukey, foi utilizada para a comparação dos tempos de preparo. O nível de significância adotado foi de 5%. Resultado: Ocorreram desvios na trajetória do canal em ambos os grupos, mas a diferença entre estes não foi significativa. O tempo de trabalho requerido pela combinação dos sistemas Pathfile + ProTaper Universal foi significativamente maior do que o requerido pelo sistema Twisted Files. Conclusão: Os dois sistemas apresentaram performances semelhantes em relação à preservação da trajetória do canal; no entanto, o tempo de trabalho requerido pelo sistema Twisted Files foi menor.

Introduction: Nickel-titanium (NiTi) rotary instruments reduce procedural errors and the time required for root canal preparation. The aim of this study was to compare two rotary NiTi instrumentation systems-Pathfile + ProTaper Universal versus Twisted Files-as to their ability to maintain original canal morphology and the time they require to prepare curved root canals. Material and Method: The mesial canals of 32 human mandibular molars (with curvature angles between 20 and 40 degrees) were selected for the study, and divided at random into two groups of 16 canals each. The canals were prepared by an endodontist using either the combination of Pathfile and ProTaper Universal instruments (Group PT) or Twisted Files (Group TF). The double digital radiograph technique, pre- and post-instrumentation, was used by three endodontists to assess whether apical transportation and/or aberration in root canal morphology occurred. The initial and final images of the root canals were compared by superimposition through computerized analysis and with the aid of magnification. The odds ratio test was used to compare root canal morphology preservation, and ANOVA complemented by Tukey's test was used to compare preparation times. The significance level was set at 5%. Result: Deviation in root canal trajectory occurred in both groups, although the differences were not significant. The preparation time required by the Pathfile + ProTaper Universal combination was significantly longer than that required by the Twisted Files system. Conclusion: Both systems showed similar performances regarding the ability to maintain original root canal morphology; however, the preparation time required by the Twisted Files system was shorter.

Comparison among manual instruments and PathFile and Mtwo rotary instruments to create a glide path in the root canal preparation of curved canals.

INTRODUCTION: Nickel-titanium rotary instruments reduce procedural errors and the time required to finish root canal preparation. The goal of this study was to evaluate the occurrences of apical transportation and canal aberrations produced with different instruments used to create a glide path in the preparation of curved root canals, namely manual K-files (Dentsply Maillefer, Ballaigues, Switzerland) and PathFile (Dentsply Maillefer) and Mtwo (Sweden and Martina, Padua, Italy) nickel-titanium rotary files. METHODS: The mesial canals of 45 mandibular first and second molars (with curvature angles between 25° and 35°) were selected for this study. The specimens were divided randomly into 3 groups with 15 canals each, and canal preparation was performed by an endodontist using #10-15-20 K-type stainless steel manual files (group M), #13-16-19 PathFile rotary instruments (group PF), and #10-15-20 Mtwo rotary instruments (group MT). The double digital radiograph technique was used, pre- and postinstrumentation, to assess whether apical transportation and/or aberration in root canal morphology occurred. The initial and final images of the central axis of the canals were compared by superimposition through computerized analysis and with the aid of magnification. The specimens were analyzed by 3 evaluators, whose calibration was checked using the Kendall agreement test. RESULTS: No apical transportation or aberration in root canal morphology occurred in any of the teeth; therefore, no statistical analysis was conducted. CONCLUSIONS: Neither the manual instruments nor the PathFile or Mtwo rotary instruments used to create a glide path had any influence on the occurrence of apical transportation or produced any canal aberration.

Uso de rotatórios pathfile e mtwo como acesso inicial no preparo endodôntico: comparação com limas manuais em canais curvos / Use of rotation and pathfile MTwo as initial access in endodontic treatment: a comparison with hand files in curved canals

Introdução: Instrumentos rotatórios em níquel-titânio reduzem erros processuais e o tempo requerido para finalização do preparo do canal radicular. O objetivo deste estudo foi avaliar as ocorrências de transporte apical e aberrações nos canais produzidas com diferentes instrumentos utilizados para a criação de trajetória-guia (“glide path”) no preparo de canais curvos: limas manuais K e limas rotatórias em níquel-titânio PathFile e Mtwo. Material e Métodos: Os canais mesiais de 45 primeiros e segundos molares inferiores (com ângulos de curvatura entre 25 e 35 graus) foram selecionados para o estudo. As amostras foram divididas aleatoriamente em três grupos de 15 canais cada e o preparo foi realizado por um endodontista utilizando limas manuais de aço inoxidável tipo K #10-15-20, conicidade 0,02 (grupo M), instrumentos rotatórios PathFile #13-16-19, conicidade 0,02 (grupo PF) e instrumentos rotatórios Mtwo #10/04- #15/05- #20/06 (grupo MT). Foi utilizada a técnica da dupla radiografia digital, pré e pós-instrumentação, para avaliar se ocorreu transporte apical e/ou aberrações na morfologia dos canais. Por meio de uma análise computadorizada e com o auxílio de magnificação, as imagens inicial e final do eixo central foram comparadas por meio de sua sobreposição. Os espécimes foram analisados por 3 avaliadores, cuja calibração foi checada por meio do teste de concordância de Kendall. Resultados: Não ocorreu transporte apical nem aberração na morfologia do canal em 100% dos dentes, portanto nenhuma análise estatística foi realizada. Conclusão: Tanto os instrumentos rotatórios PathFile e Mtwo quanto os instrumentos manuais utilizados para a criação de trajetória-guia não exerceram influência sobre a ocorrência de transporte apical nem promoveram aberrações na morfologia dos canais .

Introduction: Nickel-titanium rotary instruments reduce procedural errors and the time required to finish root canal preparation.The goal of this study was to evaluate the occurrences of apical transportation and canal aberrations produced with different instruments used to create a glide path in the preparation of curved root canals, namely: manual K files and PathFile and Mtwo nickel-titanium rotary files. Methods:The mesial canals of 45 mandibular first and second molars (with curvature angles between 25 and 35 degrees) were selected for this study. The specimens were divided randomly into three groups with 15 canals each, and canal preparation was performed by an endodontist using #10-15-20 K-type stainless steel manual files (Group M), #13-16-19 PathFile rotary instruments (Group PF), and #10-15-20 Mtwo rotary instruments (Group MT). The double digital radiograph technique was used, pre- and post-instrumentation, to assess whether apical transportation and/or aberration in root canal morphology occurred. The initial and final images of the central axis of the canals were compared by superimposition through computerized analysis and with the aid of magnification. The specimens were analyzed by 3 evaluators, whose calibration was checked using the Kendall agreement test. Results: No apical transportation or aberration in root canal morphology occurred in any of the teeth; therefore, no statistical analysis was conducted. Conclusion: Neither the manual instruments nor the PathFile or Mtwo rotary instruments used to create a glide path had any influence on the occurrence of apical transportation or produced any canal aberration

Endodontic flare-ups: a prospective study.

The objective of this prospective clinical study was to evaluate the incidence of flare-ups (pain and/or swelling requiring endodontic interappointment and emergency treatment) and identify the risk factors associated with their occurrence in patients who received endodontic treatment from June 2006 to June 2007 at the endodontics clinic of the São Paulo Dental Association (APCD), Jardim Paulista branch, São Paulo, Brazil. The incidence of flare-ups was 1.71% out of 408 teeth that had received endodontic therapy. Statistical analysis using the chi-squared test (P < .05) indicated a direct correlation between the flare-up rate and the presence of a periradicular radiolucency.