A comparative study of cyclic fatigue of 6 endodontic systems. An in vitro study.

Background: Mechanical preparation and the formation of space for adequate obturation are included in root canal shaping, but the complex root canal anatomy may be affect it. Manufacturers have created different alloys like M-Wire, Blue-Wire, Gold-Wire or R-phase. Objective: This investigation was performed to verify the null hypothesis that there were not significant differences between size 25 instruments ESP Files Thermoflex, Protaper Ultimate, Protaper Next, Blueshaper, One Curve and 2Shape about cyclic fatigue and length of broken fragments. Material and Methods: 180 new size 25 files of the systems investigated were selected (n=30). Files were used with Endo Mate DT endo motor with speed and torque recommended by manufacturers, holding the instruments with clamping mechanism, with passive adjustment, glycerine and without pressure in a stainless-steel block. The time was calculated in seconds until fracture. Number of fatigue cycles was determined as (Resistance (s) x Speed)/60. Separated fragment lengths were calculated with digital Vernier caliper. Statistical analysis was carried out with the SPSS 18 programme at a 95% confidence level, using Levene´s Test to compare variances, Welch's Test to compare means, and Games-Howell´s Test to reveal differences between groups. Results: Levene's Test determined no equal variances (P<0.05). Welch's Test and ANOVA (P<0.05) showed significant differences in cyclic fatigue and separated fragment lengths. Games-Howell's and Bonferroni´s Test established significant differences in multiple comparisons (P<0.05). Conclusions: ESP Files Thermoflex was superior in cyclic fatigue. About separated fragment lengths, ESP Files Thermoflex, Protaper Ultimate and Blueshaper obtained longer lengths. Key words:Cyclic fatigue, continuous movement, separated fragment lengths, rotary systems.

A Comparative Study of Cyclic Fatigue of 10 Different Types of Endodontic Instruments: an in Vitro Study.

OBJECTIVE: This study was designed to test the null hypothesis that there were no significant differences between size 25 files F360, F6 SkyTaper, Hyflex EDM, iRace, Neoniti, One Shape Protaper Next, Reciproc, Revo-S and Wave One Gold in terms of resistance to cyclic fatigue and length of broken fragments. MATERIAL AND METHODS: 300 new size 25 files of the systems studied were selected (n=30). The instruments were mechanized with a X-Smart Plus endo motor at the speed and torque recommended by the manufacturer, holding the instruments steady with a clamping mechanism, with passive adjustment and without pressure in a stainless-steel block. The time was calculated in seconds until fracture. The number of fatigue cycles was calculated as (Resistance (s) x Speed)/60. The separated fragment lengths were measured with a digital Vernier calliper. A statistical analysis was performed with the SPSS 18 programme at a 95% confidence level, using the Levene´s Test to compare variances, the Welch's Test to compare means, and the Games-Howell´s Test to reveal differences between groups. RESULTS: The Levene's Test showed no equal variances (P<0.05). The Welch's Test (P<0.05) showed significant differences in cyclic fatigue and separated fragment lengths. The Games-Howell test (P<0.05) exhibited significant differences in multiple comparisons, (P<0.05). CONCLUSIONS: The systems with CM-Wire (Hyflex EDM and Neoniti) were superior in resistance to the other systems for cyclic fatigue. For separated fragment lengths, F360 (conventional NiTi) and Reciproc (M-Wire) were better significantly better in terms of resistance.

Comparison of Shaping Ability of 10 Rotary and Reciprocating Systems: an In Vitro Study with AutoCad.

OBJECTIVE: The aim of this study was to compare the cutting are, root canal anatomy preservation and non-instrumented areas of F360®, F6-SkyTaper®, Hyflex-EDM®, iRACE®, Neoniti®, O.Shape®, P.Next®, Reciproc®, Revo-S® and Wave-One-Gold® size 25 files. MATERIALS AND METHODS: 300 teeth with a single straight root and a circular or elliptical root canal were divided into 10 groups (1-F360®, 2- F6-SkyTaper®, 3-Hyflex-EDM®, 4-iRACE®, 5-Neoniti®, 6-O.Shape®, 7-P.Next®, 8-Reciproc®, 9-Revo-S® and 10-Wave-One-Gold®) cut into 3 cross sections using an ultrafine cutting disc. They were photographed under a stereo microscope and preinstrumentation analyses were made before rebuilding the teeth with# 10 K- File and epoxy glue. A glide path was created with #10 and #15 K files and each group was instrumented using rotary or reciprocating systems. Cutting areas, root canal anatomy preservation and non-instrumented areas were analyzed using the AutoCAD 2015 Levene's test, the Welch´s test, and the Games-Howell´s test. The Pearson's chi-squared test was used for statistical analysis. RESULTS: Levene's test showed no equality of variances (P<0.05), therefore Welch´s and Games-Howell's tests were applied to cutting areas, showing significant differences in all thirds and overall (P<0.05). No differences in root canal anatomy preservation were observed (P>0.05). In non-instrumented areas, significant differences were found (P<0.05) in middle third being better in Reciproc®, Neoniti® and WaveOneGold®, and in apical thirds being higher P.Next®, Reciproc®, HyflexEDM®, Neoniti® and WaveOneGold®. CONCLUSIONS: In cutting area, P.Next® and Reciproc® were superior in coronal third, Neoniti® and Hyflex EDM® medially and apically and Neoniti® and Reciproc® overall. Regarding the root canal anatomy preservation, all systems were similar. For non-instrumented areas, all systems achieved similar results coronally, but Reciproc®, Neoniti® and Wave One Gold® were superior in middle third and P.Next®, Reciproc®, Hyflex EDM®, Neoniti® and Wave One Gold® were superior in apically.

Assessment Using AutoCAD Software of the Preparation of Dentin Walls in Root Canals Produced by 4 Different Endodontic Instrument Systems.

Objectives. To compare the effectiveness of four instrument systems for preparing oval root canals: manual instrumentation (Step-Back technique), ProTaper Universal, ProTaper Next, and Wave One. Material and Methods. For the purpose of this assessment, 60 teeth extracted for orthodontic or periodontal reasons, specifically canines and premolars with full coronal and root anatomy, were used and 15 samples were assigned to each group. The section of the canals was compared before and after instrumenting and the section of untouched canal wall was measured using AutoCAD software. The data was analysed by means of Shapiro-Wilk, ANOVA, and Kruskal-Wallis tests. Results. In the apical third, 100% of the canals were prepared with all the systems. In the middle third, a p value of 0.5989 in the Kruskal-Wallis test was obtained, which indicates no significant difference between the groups. At the coronal third level, the results obtained revealed that Wave One had a significantly lower mean average than the rest (p < 0.05). Conclusions. There are no differences between the various root canal instrument systems in the apical and middle thirds. At the coronal third level, Wave One system showed performance significantly worse than the rest, among which there were no differences.

Estudio comparativo del área de corte de los sistemas de instrumentación F360, i-Race, Protaper Next y Reciproc al microscopio estereoscópico con AutoCAD / Comparative study of cutting area of F360, i-Race, Protaper Next and Reciproc instrumentation systems to stereoscopic microscope with AutoCAD

Objetivos: Comparar área de corte, mantenimiento de anatomía y zonas no instrumentadas de F360, i-Race, P.Next y Reciproc con calibre #25. Material y métodos: 120 dientes unirradiculares rectos con un conducto (n=30). La LT fue calculada con lima H #10 dejándola al límite del foramen apical y restando 0,5mm. Dientes seccionados con pieza de mano y disco diamantado. Los cortes se observaron al microscopio estereoscópico. Los dientes se reconstruyeron con lima H #10 y superglue. Área de corte y mantenimiento de anatomía se estudiaron con AutoCAD, y zonas no instrumentadas con microscopio y AutoCAD. Análisis estadístico se realizó con Test de Levene, ANOVA, de Welch, de Tukey, de Bonferroni, de Games-Howell y Chi-Cuadrado de Pearson. Resultados: Varianzas iguales (Test de Levene, p>0,05) en tercios pudiendo utilizar ANOVA y observando diferencias significativas (p<0,05). Diferencias significativas entre F360 y P.Next y Reciproc en coronal, entre Reciproc y F360 en medio, y entre P.Next e i-Race y Reciproc en apical (tests de Tukey y de Bonferroni, p<0,05). Globalmente no se asumieron varianzas iguales y se utilizó el Test de Welch (p<0,05). Diferencias significativas entre F360 y Reciproc (Games-Howell, p<0,05). En el mantenimiento de la anatomía, se encontraron diferencias significativas (Chi-Cuadrado, p<0,05). En relación a las zonas no instrumentadas, no existieron diferencias significativas (Chi-Cuadrado, p<0,05). Conclusiones: Reciproc fue superior en el área de corte. P.Next y Reciproc fueron más eficaces en el mantenimiento de la anatomía. Respecto a las zonas no instrumentadas, no existieron diferencias significativas

Aim: Compare the cutting area, maintenance of anatomy and non-instrumented areas of F360, i-Race, P.Next and Reciproc with size #25. Methods: 120 straight single-rooted teeth with a canal (n=30). The LT was calculated with H-file #10 leaving the limit of the apical foramen and subtracting 0.5mm. Teeth were sectioned with piece of hand and diamond disc. The sections were observed at stereoscopic microscope. The teeth were reconstructed with H-file #10 and superglue. Cutting area and maintenance of anatomy were studied with AutoCAD 2013, and non-instrumented areas with microscope and AutoCAD. Statistical analysis was performed with Levene´s Test, ANOVA, Welch, Tukey, Bonferroni and Games-Howell and Pearson´s Chi-square. Results: Equal variances (Levene test, p>0.05) in thirds and can used ANOVA and significant differences were observed (p<0.05). Significant differences between F360 and P.Next and Reciproc in coronal, in middle between Reciproc and F360, and in apical between P.Next and i-Race and Reciproc (tests of Bonferroni and Tukey, p<0.05). Globally, equal variances were not assumed using the Welch Test (p<0.05). Significant differences between F360 and Reciproc (Games-Howell, p<0.05). In maintenance of anatomy, significant differences were found (Chi-Cuadrado, p<0.05). Conclusions: Reciproc was higher in the cutting area. P.Next and Reciproc were more effective in maintenance of anatomy. For non-instrumented areas, there were not significant differences

A Comparative Study of Shaping Ability of four Rotary Systems.

PURPOSE: This study compared the cutting area, instrumentation time, root canal anatomy preservation and non-instrumented areas obtained by F360(®), Mtwo(®), RaCe(®) and Hyflex(®) files with ISO size 35. MATERIAL AND METHODS: 120 teeth with a single straight root and root canal were divided into 4 groups. Working length was calculated by using X-rays. The teeth were sectioned with a handpiece and a diamond disc, and the sections were observed with Nikon SMZ-2T stereoscopic microscope and an Intralux 4000-1 light source. The groups were adjusted with a preoperative analysis with AutoCAD. The teeth were reconstructed by a #10 K-File and epoxy glue. Each group was instrumented with one of the four file systems. The instrumentation time was calculated with a 1/100 second chronometer. The area of the thirds and root canal anatomy preservation were analyzed with AutoCAD 2013 and the non-instrumented areas with AutoCAD 2013 and SMZ-2T stereoscopic microscope. The statistical analysis was made with Levene's Test, ANOVA, Bonferroni Test and Pearson´s Chi-square. RESULTS: Equal variances were shown by Levene's Test (P > 0.05). ANOVA (P > 0.05) showed the absence of significant differences. There were significant differences in the instrumentation time (P < 0.05). For root canal anatomy preservation and non-instrumented areas, there were no significant differences between all systems (P > 0.05). CONCLUSIONS: The 4 different rotary systems produced similar cutting area, root canal anatomy preservation and non-instrumented areas. Regarding instrumentation time, F360(®) was the fastest system statistically.

A Comparative in Vitro Study of Apical Microleakage with Five Obturation Techniques: Lateral Condensation, Soft-Core®, Obtura II®, Guttaflow® and Resilon®.

AIM: A comparison was made between the root canal lateral condensation technique and other condensation techniques in which physical (temperature: Soft-Core®, Obtura II®) or chemical changes (condensation: Guttaflow®, Resilon®) may affect the dimensional stability of obturation and thus favor apical microleakage. MATERIALS AND METHODS: A total of 212 single-root teeth removed for orthodontic or periodontal reasons were randomized to 5 groups of 40 teeth each. Six samples were used as positive controls, and another 6 as negative controls. The teeth were worked with the Hero 642 system, and each group was obturated using a different technique: lateral condensation, Obtura II®, Soft-Core®, Guttaflow® or Resilon®. The samples were immersed in black ink, and after 72 hours the teeth were transparentized using the technique described by Robertson. Filtration of the ink was measured under the stereoscopic microscope. Analysis of variance and post-hoc testing were used for the statistical analysis. RESULTS: The Soft-Core® obturated group showed significantly greater microleakage than the other groups, with no differences among the rest of the groups. CONCLUSIONS: Under the conditions of this study, the teeth obturated with the Soft-Core® technique showed greater apical microleakage than the other systems.