Luciana Ferraz Gominho

Histologic evaluation of pulpotomy performed with ethyl-cyanoacrylate and calcium hydroxide

The aim of this study was to evaluate histological aspects of the pulp-dentin complex of dogs submitted to pulpotomy and capped with ethyl-cyanoacrylate and calcium hydroxide. Thirty dog teeth were divided into 2 groups of 15 as follows: Group 1 - ethyl-cyanoacrylate; Group 2 - calcium hydroxide. The pulpotomies were carried out following all of the treatment precautions recommended for dogs. After 30 days the specimens were submitted to histological preparation and were then blindly evaluated by a histologist. Data were analyzed statistically by the Fisher exact test, comparing the two groups. After 30 days, the presence of a hard tissue barrier was observed in 83.3% of Group 1, and in 100% of Group 2 (p = 0.478). A continuous hard tissue barrier was observed in 50% of the ethyl-cyanoacrylate group and 75% of the calcium hydroxide group (p = 0.652). It can be concluded that both materials induced hard tissue barrier formation, but Group 2 had a higher percentage than Group 1, with no significant statistical differences; the differences observed between the different barriers (continuous/non-continuous) were not significant between groups and there was no pulpal necrosis in either group.

Apical extrusion of debris from root canals using reciprocating files associated with two irrigation systems

AIM To compare apical extrusion of debris in canals prepared with two reciprocating file systems and two different irrigation systems. METHODOLOGY Forty single straight root canals in human mandibular pre-molars were prepared using Reciproc R40 (REC) and WaveOne Large (WO) instruments. Before preparation, the dimensions of a size 40 instrument from each system were measured under scanning electron microscopy (SEM) at 80X. The teeth were randomly divided into four different groups of 10: REC and VPro EndoSafe (REC/VPro); WO/VPro; REC and conventional irrigation (REC/CI); and WO/CI Eppendorf tubes containing a single tooth were weighed on an analytical balance to the nearest 0.1 mg before instrumentation. Irrigation was performed with a total volume of 8 mL of 2.5% sodium hypochlorite. After instrumentation, the teeth were removed from the Eppendorf tube 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 debris weights was calculated and statistically evaluated using analysis of variance (two-way anova) with a significance level of 0.05. RESULTS No significant difference was observed between the VPro and CI irrigation systems (P > 0.05). Apical extrusion of debris was confirmed in all samples, and extrusion was greater in the REC groups than in the WO groups (P < 0.05). The WO file had a 20% smaller diameter at the tip (D0 ) than the measurement provided by the manufacturer. CONCLUSIONS All systems were associated with apical extrusion of debris. The WO system was associated with less extrusion than the REC system. The amount of extruded debris was independent of the irrigation system used and was related to the instrumentation technique. Morphological analysis of instruments using SEM revealed no correlation between the diameter provided by the manufacturer and the measured diameter for the WO Large file.

Occurence of dentinal defects after root canal preparation with R-phase, M-Wire and Gold Wire instruments: a micro-CT analysis

BackgroundThis study aims to evaluate the frequency of dentinal defects after root canal preparation with the ProTaper NEXT, K3XF and WaveOne GOLD systems using microcomputed tomography.MethodsSixty permanent mandibular incisors with a single canal were selected. Inspection of the teeth was performed under a stereomicroscope (15x) to observe the presence of pre-existing cracks and fractures lines. Samples were divided into three experimental groups (n = 20): ProTaper NEXT (PTN), K3XF (K3XF) and WaveOne GOLD (WOG). Specimens were scanned through high-resolution microcomputed tomography before and after the preparation of the root canal. Subsequently, all the axial images were examined by two different methods to find possible dentinal defects. Furthermore, an analysis of each millimeter of ten apical millimeters was also performed. The absence or presence of dentinal defects was screened by 3 pre-calibrated blinded examiners.ResultsAfter analysing all 45,720 slices, dentinal defects were observed in 48,33% (22096 slices). PTN, K3XF and WOG groups represented 11,11% (5079 slices), 17,22% (7873 slices) and 20% (n = 9144) of the cross-sectional images, respectively. At 10 apical millimeters (600 slices), 33,33% (200 slices) presented some dentinal defects, representing 7,22% (43 slices), 13,33% (80 slices) and 12,77% (77 slices) of the cross-sectional images in the PTN, K3XF and WOG groups, respectively. All the dentinal defects presented in the postoperative images existed in the images prior to instrumentation.ConclusionsThere was no correlation between the preparation of a root canal using the PTN, K3XF and WOG systems and the formation of new dentinal defects.

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 manufacturers 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.

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.

Effects of Reciproc, ProTaper Next and WaveOne Gold on Root Canal Walls: A Stereomicroscope Analysis

Introduction: The aim of this study was to analyse the potential occurrence of dentinal defects after root canal preparation using three engine-driven instruments. Methods and Materials: Eighty permanent mandibular incisors were selected. Twenty teeth did not undergo preparation, and the remaining teeth were divided into three groups (n=20): Reciproc (REC), ProTaper Next (PTN) and WaveOne Gold (WOG). The samples were dyed with methylene blue, sectioned perpendicularly to the long axis in 3-, 6- and 9-mm slices and were finally observed under a stereomicroscope (under 25×). The absence/presence of dentinal defects was documented by two blind observers. The data were analysed using Pearson’s chi-squared test with a confidence level of 95% (P=0.05). The time to prepare the samples was recorded, and the groups were compared using F-test (ANOVA). Results: The control group did not present any defects, and the differences between the control and experimental groups were statistically significant (P<0.05). WOG, PTN and REC caused microcracks on 60%, 33.33% and 18.33% of the samples, respectively. No significant differences between the groups in the 3-mm sections (P=0.126) were observed. There were significant differences in the 6-mm (P=0.042) and 9-mm sections (P<0.001). When WOG and PTN were used to perform root canal preparation, a significant difference was found in the average time (P=0.047). Conclusion: All the used instruments caused dentinal defects in the root dentin. All the instruments were used to perform the preparation with a similar average time.

Análise In Vitro da Infiltração Cervical Bacteriana em Dentes Preenchidos com Pastas de Hidróxido de Cálcio

Objetivo: Avaliar o efeito de barreira fisica de duas pastas de hidroxido de calcio com diferentes veiculos em canais radiculares expostos a saliva humana por um periodo de vinte dias. Metodo: Cinquenta dentes humanos uniradiculares foram divididos em dois grupos experimentais com vinte dentes cada, um grupo controle positivo com 5 dentes e um grupo controle negativo com 5 dentes. O preparo quimico-mecânico tipo coroa-apice foi realizado sob irrigacao com NaOCl a 1% e E.D.T.A. a 17%. Apos esterilizacao dos dentes, foram aplicadas a pasta de hidroxido de calcio em agua destilada (Grupo I) e pasta de hidroxido de calcio com paramonoclorofenol canforado (PMCC) em polietilenoglicol 400 (Grupo II). O comportamento do efeito de barreira fisica das pastas foi observado durante um periodo de 20 dias, atraves do uso de aparato nos quais foram inseridos meio de cultura Brain Heart Infusion (BHI), o dente com as referidas pastas e saliva humana em BHI, todos acomodados separadamente. Resultados: Apos periodo analisado, ocorreu turvacao em apenas 1 caso dos vinte especimes (5%) do grupo com hidroxido de calcio em agua destilada (Grupo I). No grupo com hidroxido de calcio e PMCC em polietilenoglicol 400 (Grupo II) ocorreu turvacao em 5 meios de cultura (25%). Conclusao: Ambas as pastas de hidroxido de calcio analisadas atuaram como barreira fisica a infiltracao cervical de canais radiculares expostos ao meio contaminado, contudo observou-se que o grupo com hidroxido de calcio em agua destilada obteve menor numero de especimes infiltrados, com diferenca estatistica comprovada, em relacao ao grupo com hidroxido de calcio e PMCC em polietilenoglicol 400.(AU) Objective: To evaluate the physical barrier effect of two calcium hydroxide pastes prepared with different vehicles in root canals exposed to human saliva for 20 days. Method: Fifty single-rooted human teeth were divided into two experimental groups with 20 teeth each, one positive control group with 5 teeth and one negative control group with 5 teeth. A crown-down chemomechanical preparation was performed under irrigation with 1% NaOCl and 17% EDTA. After sterilization of the teeth, the canals were filled with either a paste of calcium hydroxide and distilled water (Group I) or a paste of calcium hydroxide with camphorated paramonochlorophenol (PMCC) and polyethylene glycol 400 (Group II). The behavior of the physical barrier effect of the pastes was observed during 20 days, through the use of an apparatus in which were placed brain heart infusion (BHI) culture medium, the tooth filled with paste and human saliva in BHI, all of them accommodated separately. Results: After the established period, turbidity occurred in only 1 of the 20 specimens (5%) of the group filled with a paste of calcium hydroxide and distilled water (Group I). In the group filled with a paste of calcium hydroxide and PMCC in polyethylene glycol 400 (Group II) turbidity occurred in 5 specimens (25%). Conclusion: It may be concluded that both calcium hydroxide pastes analyzed in the study acted as a physical barrier to coronal leakage in root canals exposed to a contaminated environment; however, the group filled with calcium hydroxide and distilled water showed a smaller number of specimens with leakage, differing significantly from the group filled with calcium hydroxide with PMCC and polyethylene glycol 400.(AU)