Bacterial Reduction after Gutta-Percha Removal with Single vs. Multiple Instrument Systems

Introduction: The aim of this study was to evaluate the effectiveness of a reciprocating single-instrument system (Reciproc-REC) compared with combined continuously rotating multiple-instrument systems [D-Race (DR) and BioRace (BR)] in reducing Enterococcus faecalis (E.f.) after gutta-percha removal. Methods and Materials: Forty-six extracted human maxillary incisors were prepared and contaminated with E.f. strain (ATCC 29212) for 30 days. The samples were obturated and randomly divided into two experimental groups for gutta-percha removal (n=23): a REC group (R50) and a DR/BR group (DR1, DR2 and BR6). A standardized irrigation with 0.9% saline solution was performed. Root canal samples were taken with paper points before (S1) and after (S2) the removal of gutta-percha to establish bacterial quantification by culture. The time required for gutta-percha removal was also recorded. Positive and negative control groups (n=6) were used to test bacterial viability and control asepsis, respectively. Data were analysed using t-Student and one-way ANOVA tests (5% margin of error). Results: The mean percentage of bacterial reduction was significantly higher in DR/BR group (84.2%) than in REC group (72.3%) (P<0.05). The mean time for obturation removal was 74.00 sec in REC group and 107.53 sec in DR/BR group (P<0.05). Conclusion: The combined continuously rotating multiple-instrument system was more effective in reducing bacteria after the removal of gutta-percha than the single-instrument system. None of the tested systems was able to completely eliminate root canal infection after gutta-percha removal. Thus, additional techniques should be considered.Keywords: Endodontics; Enterococcus faecalis; Instrumentation; Retreatment; Root Canal Instrumentatio

Evaluation of Apically Extruded Debris during Root Canal Retreatment Using ProTaper Next and Reciproc in Severely Curved Canals

Introduction: To compare the apical extrusion of debris produced during root obturating material removal from severely curved root canals using either Reciproc (REC) or ProTaper Next (PTN) systems. Methods and Materials: Twenty-six mesial canals of lower molars were instrumented, filled and allocated into two groups (n=13). Micro-computed tomographic images were performed to determine the root canal configuration (Vertucci’s type IV) and initial volume of obturation. One Eppendorf tube was assigned per canal and weighed (10-4g) before and after removal of the obturating material. The difference between the initial and final weights was calculated and statistically evaluated. Results: Apical extrusion of debris was confirmed in all samples, and the mean amount of apical extrusion was similar between both groups (0.061±0.014 g in PTN vs. 0.065±0.016 g in REC samples) (P<0.05). Conclusion: Both systems caused apical extrusion of debris with no differences between PTN and REC systems.Keywords: Gutta-Percha; Root Canal Filling Materials; Root Canal Retreatmen

Apical Extrusion of Debris Produced during Continuous Rotating and Reciprocating Motion

This study aimed to analyse and compare apical extrusion of debris in canals instrumented with systems used in reciprocating and continuous motion. Sixty mandibular premolars were randomly divided into 3 groups (n=20): the Reciproc (REC), WaveOne (WO), and HyFlex CM (HYF) groups. One Eppendorf tube per tooth was weighed in advance on an analytical balance. The root canals were instrumented according to the manufacturer’s instructions, and standardised irrigation with 2.5% sodium hypochlorite was performed to a total volume of 9 mL. After instrumentation, the teeth were removed from the Eppendorf tubes and incubated at 37°C for 15 days to evaporate the liquid. The tubes were weighed again, and the difference between the initial and final weight was calculated to determine the weight of the debris. The data were statistically analysed using the Shapiro-Wilk, Wilcoxon, and Mann-Whitney tests (α=5%). All systems resulted in the apical extrusion of debris. Reciproc produced significantly more debris than WaveOne (p<0.05), and both systems produced a greater apical extrusion of debris than HyFlex CM (p<0.001). Cross section and motion influenced the results, despite tip standardization

Shaping Ability of Single-File Systems with Different Movements: A Micro-Computed Tomographic Study

Introduction: This study aimed to perform a rigorous sample standardization and also evaluate the preparation of mesiobuccal (MB) root canals of maxillary molars with severe curvatures using two single-file engine-driven systems (WaveOne with reciprocating motion and OneShape with rotary movement), using micro-computed tomography (micro-CT). Methods and Materials: Ten MB roots with single canals were included, uniformly distributed into two groups (n=5). The samples were prepared with a WaveOne or OneShape files. The shaping ability and amount of canal transportation were assessed by a comparison of the pre- and post-instrumentation micro-CT scans. The Kolmogorov-Smirnov and t-tests were used for statistical analysis. The level of significance was set at 0.05. Results: Instrumentation of canals increased their surface area and volume. Canal transportation occurred in coronal, middle and apical thirds and no statistical difference was observed between the two systems (P&gt;0.05). In apical third, significant differences were found between groups in canal roundness (in 3 mm level) and perimeter (in 3 and 4 mm levels) (P&lt;0.05). Conclusion: The WaveOne and One Shape single-file systems were able to shape curved root canals, producing minor changes in the canal curvature.Keywords: Micro-Computed Tomography; OneShape; Reciprocating Motion; Rotary System; WaveOn

Retratamento endodôntico associado à instalação de retentor de fibra de vidro: relato de caso: Endodontic retreatment associated with the installation of fiberglass retainer: case report

Após o tratamento endodôntico, o surgimento ou a permanência de sinais e/ou sintomas inflamatórios e infecciosos refletem o insucesso, sendo indicado o retratamento endodôntico. Neste relato de caso, foi descrito o retratamento do incisivo lateral superior esquerdo realizado em sessão única com instalação de retentor intra-radicular de fibra de vidro. Paciente foi encaminhada para a Clínica de Especialização em Endodontia da Faculdade COESP com achados de escurecimento dentário, restauração em resina composta infiltrada, tratamento endodôntico insatisfatoriamente obturado e rarefação óssea circunscrita na região periapical. O diagnóstico clínico pulpar e periapical estabelecido foi de tratamento endodôntico prévio e periodontite apical assintomática. Após abertura coronária, removeu-se guta-percha com inserto ultrassônico e microscópio operatório, seguido do uso de instrumento mecanizado Reciproc® R25. Durante o procedimento, foi usada solução de NaOCl a 2,5%. A odontometria eletrônica foraminal foi seguida de novo preparo do canal com os instrumentos Reciproc® Blue R40 e R50. Para qualificar a limpeza, foram utilizados instrumentos mecanizados XP Endo Finisher e irrigação ultrassônica passiva com solução de NaOCl a 2,5% e EDTA a 17%. Após a obturação do canal e preparo de espaço intra-radicular, instalou-se um retentor de fibra de vidro e a coroa selada com resina composta. O retratamento realizado com auxílio de tecnologias favorece a limpeza e desinfecção dos canais. A reabilitação de forma imediata e minimamente invasiva permite a satisfação estética, funcionalidade biomecânica e menor chance de recontaminação intracanal. Tais fatores associados permitem a manutenção de dentes naturais e saudáveis na cavidade oral

Analysis of Dental Enamel Surface Submitted to Fruit Juice Plus Soymilk by Micro X-Ray Fluorescence: In Vitro

Objective. This paper aimed to analyze the in vitro industrialized fruit juices effect plus soy to establish the erosive potential of these solutions. Materials and Methods. Seventy bovine incisors were selected after being evaluated under stereomicroscope. Their crowns were prepared and randomly divided into 7 groups, using microhardness with allocation criteria. The crowns were submitted to the fruit juice plus soy during 15 days, twice a day. The pH values, acid titration, and Knoop microhardness were recorded and the specimens were evaluated using X-ray microfluorescence (µXRF). Results. The pH average for all juices and after 3 days was significantly below the critical value for dental erosion. In average, the pH value decreases 14% comparing initial time and pH after 3 days. Comparing before and after, there was a 49% microhardness decrease measured in groups (p<0.05). Groups G1, G2, G5, and G6 are above this average. The analysis by μXRF showed a decrease of approximately 7% Ca and 4% P on bovine crowns surface. Florida (FL) statistical analysis showed a statistically significant 1 difference between groups. Thus, a tooth chance to suffer demineralization due to industrialized fruit juices plus soy is real

A comparative study of protaper and twisted file nickel titanium instruments in curved canals preparation

Introduction. Root canal instrumentation is performed to achieve cleaning and shaping with maximum preservation of its original anatomy. However, in curved canals this approach may cause excessive damage or canal transportation. The present study aimed to evaluate changes in dentin wall caused by instrumentation of curved canals using two nickel titanium rotary systems, ProTaper and Twisted File. Material and Methods. Twenty five extracted human mandibular first molars with two separated mesial root canals were selected. Distal roots were amputated and 50 canals (25 mesiobuccal and 25 mesiolingual) were randomly assigned into two groups: group 1 - ProTaper, and group 2 - Twisted File. All files were used with torque control engine, following the manufacturer instructions. The final instruments were F3 (group 1) and #30/.06 (group 2). Pre and postoperative cross sections were obtained from coronal, middle, and apical portions. Changes in dentin wall were measured and evaluated using Bramante method and digital image software. Statistical analysis was performed using the Mann Whitney U test (p<0.05). Results. The ammount of dentin removed by ProTaper in cervical and middle canal thirds was significantly greater than with Twisted File (p=0.040 and p=0.043). ProTaper eliminated significantly greater ammount of dentin than Twisted File from mesial wall in coronal sections (p=0.039). Mean differences in distance from the center to other walls were not statistically significant in the middle and apical thirds of both groups (p>0.05). Conclusion. ProTaper system produced greater changes in cross sectional area of the root canal compared to Twisted File system