Diana Santana de Albuquerque

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.

In vitro comparative study of manual and mechanical rotary instrumentation of root canals using computed tomography

This in vitro study compared, using computed tomography (CT), the amount of dentin removed from root canal walls by manual and mechanical rotary instrumentation techniques. Forty mandibular incisors with dental crown and a single canal were selected. The teeth were randomly assigned to two groups, according to the technique used for root canal preparation: Group I - manual instrumentation with stainless steel files; Group II - mechanical instrumentation with RaCe rotary nickel-titanium instruments. In each tooth, root dentin thickness of the buccal, lingual, mesial and distal surfaces in the apical, middle and cervical thirds of the canal was measured (in mm) using a multislice CT scanner (Siemens Emotion, Duo). Data were stored in the SPSS v. 11.5 and SigmaPlot 2001 v. 7.101 softwares. After crown opening, working length was determined, root canals were instrumented and new CT scans were taken for assessment of root dentin thickness. Pre- and post-instrumentation data were compared and analyzed statistically by ANOVA and Tukeys post-hoc test for significant differences (p=0.05). Based on the findings of this study, it may be concluded that regarding dentin removal from root canal walls during instrumentation, neither of the techniques can be considered more effective than the other.

Apical displacement produced by rotary nickel-titanium instruments and stainless steel files.

The aim of this study was to evaluate the apical displacement produced by different rotary nickel-titanium instruments, testing the hypothesis that rotary systems with nickel-titanium instruments produce lower mean values of apical displacement than stainless steel hand instruments. A total of 100 maxillary permanent first molars were selected for the study. The mesiobuccal roots were sectioned at the top cervical third and embedded in blocks of self-curing resin. The specimens were randomly divided into 5 groups and the root canals were prepared using the following nickel-titanium instruments: Group 1 - Quantec system 2000 (Analytic Endodontics, Mexico); Group 2 - Pro-File T.0.04 (Dentsply/Maillefer, Switzerland); Group 3 - Pro-File Series 29 T.0.04 (Dentsply Tulsa, Switzerland); Group 4 - Pow-R T.0.02 (Moyco-Union Broach, USA). Specimens in Group 5 were prepared using stainless steel hand instruments Flexofile (Dentsply/Maillefer, Switzerland). All root canals were previously submitted to cervical preparation using Orifice Shaper instruments #1, 2, 3 and 4 (Dentsply/Maillefer, Switzerland). After odontometry, the remaining root canal was shaped employing increasingly larger instruments, so that the final instrument corresponded to Quantec #9, Pro-File Series 29 #6, and #35 for the other groups. Specimens in Groups 1 to 4 were prepared using an electric handpiece with 16:1 reduction at 350 rpm. The specimens in Group 5 were manually prepared. Apical displacement was measured and recorded by means of radiographic superimposition on a specific desk. Statistical analysis (ANOVA) of the results revealed that all groups presented apical displacements. Considering only the nickel-titanium instruments, Group 4 showed the lowest mean value while Groups 2 and 3 produced the highest mean apical displacement values (p<0.001).

The fracture evaluation of NiTi SMA endodontics files

The purpose of this study was to evaluate the fracture resistance and the fracture surface of NiTi SMA engine-driven endodontics files submitted to clockwise torsion. The maximum angular deflection and the maximum torque were analyzed without axial loading. The helical plastic deformations and the fracture surface morphology were evaluated by Scanning Electron Microscopic. The results showed that there was a significant statistical difference in the maximum fracture torque and no statistical difference for the angular deflection for the analyzed files. In relation to the maximum torque at the instant of the fracture, one of the brand presented better performance than the other. According to Scanning Electron Microscopic evaluation, all the files showed ductile fracture morphology.

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.

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

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.

The Promising Applications of Stem Cells in the Oral Region: Literature Review

Introduction: For a long time researchers have tried to find out a way to grow tissues back to the human body in order to solve transplantation problems by offering the unique opportunity to have their organs back, working properly, in search of life dignity. Literature Review: Stem cells seem to be present in many other tissues than researchers had once thought; and in some specific sites they can be easily collected, without the need of expensive interventions. The oral cavity is one of these regions where their collection can be accomplished, with plenty of accessible sites enriched with these precious cells. Aim: The aim of this literature review is to research where in the mouth can scientists find stem cells to be used in the near future. Key-message: The aim of this literature review is to research where stem cells can be found and collected in the oral cavity.

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.

Canal Transportation and Centering Ability of Reciproc Blue, WaveOne Gold and ProTaper Next in Simulated Curved Canals

Introduction: The aim of this study was to evaluate the canal transportation and centering ability of ProTaper Next (PTN), WaveOne Gold (WOG) and Reciproc Blue (RCB) in simulated curved resin canals. Methods and Materials : A total of 43 blocks of simulated resin canals with 40° of curvature were prepared to an apical size of 0.02. Flexofile #15 instruments were used along the root canal to reach patency. The blocks were randomly assessed and sequence instruments were used according to each system: PTN, RCB and WOG. The imposition of pre and post instrumentation images were composited and analyzed. The canal transportation and apical centralization were measured using the software GIMP (2.8.4, Creative Commons - Share Alike 4.0 International License, 2013). Data were statistically analyzed using the Shapiro-Wilk test, ANOVA test and Tukeys test. The level of significance was set at 0.05. Results: There were no statistical differences in canal transportation between three systems. The general assessment of three systems presented the RCB group with higher values of centralization and more numbers of centralized points with significant differences between the PTN and RCB groups ( P <0.05). Conclusion: In this in vitro study, there were no statistical differences in canal transportation between the RCB, WOG and PTN systems. The lowest transportation was observed in the apical region at 3 mm performed with RCB system, followed by WOG and PTN systems. The RCB demonstrated higher values of centralization and more centralized points when assessed by regions. Keywords: Canal Transportation; Centering Ability; Reciprocating; Rotary Instrumentation

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.