Effect of powder-to-water ratio on the push-out bond strength of white mineral trioxide aggregate

Aim: To evaluate the effect of powder-to-water ratio on the retention characteristics of white mineral trioxide aggregate (MTA; Angelus, Londrina, Pr, Brazil) over time. Methods: One hundred and thirty-five root dentin slices from extracted single-rooted human mandibular premolar teeth were instrumented to achieve a diameter of 1.3 mm. Three MTA groups were prepared using 4:1, 3:1, and 2:1 powder-to-water ratios. The samples were stored for 96 h and 7 and 28 days at 37°C. The push-out bond strengths were measured using an Instron testing machine. Data were analyzed using two-way analysis of variance (anova) with Bonferroni correction. Results: There was a statistically significant difference between the experimental groups at the 96-h and 7-day study periods (P = 0.002). At 96 h, the materials prepared at 2:1 ratio had the lowest bond strength than the samples prepared at the other two ratios (P < 0.001). There was a significant difference between the findings at 96-h and 28-day study periods for 2:1 and 4:1 ratios. The highest bond strength value was found at 28 days of exposure (P < 0.001). Conclusion: The powder-to-water ratio significantly interfered with the bond strength properties of white MTA. © 2015 John Wiley & A/S

Influence of cement type and thickness on polyfiber post adhesion

Introduction: To evaluate the effect of two different post space diameters and related resin cement film thicknesses on the bond strength of a polyfiber post. Materials and Methods: A total of 48 premolars were randomly divided into two according to the post space diameter: 1.1 mm and 1.5 mm. Then each group was divided into three sub-groups according to luting cement used: RelyX U100, Panavia F2.0/ED primer, Clearfil SA cement. Spirapost was then luted into the canal using luting cements. Two slices were obtained from each root specimen. Push-out tests were performed. Data was analyzed with Kruskal-Wallis and Connover post-hoc and Mann-Whitney U-test (P < 0.05). Results: Push-out bond strength was found to vary significantly according to type of adhesive system and post space diameter size (P < 0.05). The self-adhesive resin cement RelyX U100 had significantly higher bond strengths compared with the other adhesive system (P < 0.05). The self-etch adhesive system (Panavia F2.0) showed significantly lower bond strengths compared with the other systems (P < 0.05). There was a significant interaction between the luting systems and post space diameter (P < 0.05). Conclusion: The increases in post space diameter significantly reduced the bond strength of Spirapost to root dentine for both groups

Evaluation of apically extruded bacteria associated with different nickel-titanium systems

Introduction The aim of this in vitro study was to evaluate the amount of apically extruded bacteria associated with several root canal preparation systems. Methods Forty-four extracted human mandibular premolar root canals were contaminated with an Enterococcus faecalis suspension. After incubation at 37°C for 24 hours, the root canals were instrumented using the Twisted File (SybronEndo, Orange, CA), OneShape (Micro Mega, Besançon, France), and ProTaper Next (Dentsply Maillefer, Ballaigues, Switzerland). During instrumentation, apically extruded bacteria were collected into vials containing 0.9% NaCl. The microbiological samples were taken from the vials and incubated in brain-heart agar medium for 24 hours. The numbers of colony-forming units were determined. The data obtained were analyzed using Welch analysis of variance followed by post hoc Games-Howell tests. Results ProTaper Next extruded the highest amount of bacteria, whereas OneShape extruded the least compared with all the other instruments (P =.004). There was a significant difference between OneShape and ProTaper Next in the number of colony-forming units (P =.007) but not between OneShape and Twisted File (P >.05). Conclusions All instrumentation systems extruded bacteria beyond the foramen. The OneShape system extruded less bacteria compared with the Twisted File and ProTaper Next systems. © 2015 American Association of Endodontists

Effect of glide path preparation on apical debris extrusion of rotary and reciprocating single-file systems: OneShape versus WaveOne

Objectives: To assess the effect of glide path on the amount of apically extruded debris after instrumentation with WaveOne and OneShape. Materials & Methods: Forty-eight extracted human mandibular incisors were assigned to 4 groups. In groups 1 and 2, preparation was completed with WaveOne, in groups 3 and 4 canals were prepared with OneShape. Before instrumentation, in groups 1 and 3, glide path was created with PathFile 1, 2, and 3 at working length, whereas in groups 2 and 4, glide path was not performed. The weight of the extruded debris for each group was calculated by comparing the pre- and post-instrumentation weights of the eppendorf tubes. The time required for reaching full WL was also recorded. Data were analysed by Kruskal-Wallis and Mann-Whitney U tests. Results: There was no difference in the amount of debris extruded between the single file systems (P=0.234). Time required to reach full WL was significantly decreased by creating a glide path (P< 0.05). Conclusions: Creation of a glide path does not significantly affect the apically extruded debris

Efficacy of different solvents in removing gutta-percha from curved root canals: A micro-computed tomography study

The aim of this study was to compare the root filling material that remained after retreatment of curved root canals with chloroform and Endosolv R as solvents. The evaluation employed micro-computed tomography (CT) imaging. Thirty-six extracted molar teeth with curved roots were selected. After preparation with ProTaper rotary instruments, the canals were filled with gutta-percha and AH26 sealer. The teeth were randomly divided into three groups according to solvent used (n = 12) as follows: group 1: chloroform; group 2: Endosolv R; group 3: no solvent (negative control). ProTaper Universal Retreatment files were used to remove each root canal filling and then the self-adjusting file was applied for two minutes. Preoperative and postoperative micro-CT images were used to assess the percentage of residual filling material. The mean percentage of residual filling material was quantified. There were no statistically significant differences between the groups in terms of percentage volume of residual root canal filling. © 2013 Australian Society of Endodontology

Comparison of calcium hydroxide removal by self-adjusting file, EndoVac, and CanalBrush agitation techniques: An in vitro study

Objectives: This study comparatively evaluated the efficacy of self-adjusting file (SAF), Endovac, and CanalBrush irrigant agitation protocols in removing calcium hydroxide (Ca(OH)2 ) from the root canals. Materials and Methods: Sixty extracted human mandibular canine teeth were instrumented with ProTaper rotary instruments to size #40 and dressed with Ca(OH)2. The roots were randomly assigned to four groups according to irrigant agitation protocol used (n = 15). In Group 1: Conventional syringe irrigation (no activation, control); Group 2: Rotary brush agitation (CanalBrush); Group 3: Apical negative pressure irrigation (EndoVac system); and Group 4: Sonic agitation (SAF) were used. Scanning electron microscopic (SEM) evaluation was done for assessment of Ca(OH)2 removal in the coronal and apical thirds. Statistical analysis was performed by Wilcoxon and Kruskal-Wallis tests. Results: There were statistically significant differences among the groups (P = 0.218). A statistically significant difference was seen between the test groups in Ca(OH)2 removal from the apical third of the canal (P &lt; 0.05). In the coronal third, there was no difference between the groups (P &gt; 0.05). The most efficient Ca(OH)2 removal in apical third was recorded in Group 3 (EndoVac) and Group 4 (SAF) (P &lt; 0.05). In Group 4 (sonic agitation), there was no significantly difference between Ca(OH)2 removal in coronal and apical thirds. Conclusions: SAF and EndoVac showed significantly better performance than CanalBrush and conventional syringe irrigation in removing Ca(OH)2 from apical third of the root canals

The effect of glide path on the surface quality of new and used rotary and reciprocating single files: OneShape versus WaveOne

The aim of this study was to evaluate the effect of glide path preparation on the surface topography changes of WaveOne and OneShape single files using atomic force microscopy analysis. Two commercially available brands of single file systems were analyzed, including 15 specimens/brand as following: Group I; WaveOne 0.08/25 (Dentsply Maillefer, Ballaigues, Switzerland) and Group II; OneShape 0.06/25 (Micro Mega, Besançon, France). In each group, 3 new files were subjected to AFM analysis as received from manufacturer, and 12 files were analyzed after preparation of root canals. A total of 20 human maxillary molar teeth were selected. In each group, 12 files were divided into 4 subgroups according to instruments that were used in one or three root canals with or without a previous glide path (n3). After preparation the surface analysis of single files was performed on 11 different points located along a 3-mm section starting at the tip of each file using AFM. Root mean square (RMS) values were recorded to investigate the surface features of endodontic files. The differences between RMS values were tested by one-way ANOVA. There was no statistically significant difference between the groups (p>0.05). Creation of a glide path did not affect the surface topography of single file systems. © 2014 Wiley Periodicals, Inc

Evaluation of the dentinal wall adaptation ability of MTA Fillapex using stereo electron microscope

Background: An ideal root canal obturation requires a complete dentinal wall adaptation of sealer and Gutta-percha combinations without any gap formations. Aims: The aim of the study was to evaluate the dentinal wall adaptation ability of MTA Fillapex root canal sealer using stereo electron microscope (SEM). Methods: Twenty-four, single-rooted, human maxillary incisor teeth were used. All canals were prepared with a rotary nickel-titanium (Ni-Ti) instrument to a size F3 file. Teeth divided into two equal groups and one of the experimental groups was filled with AH Plus, and the other group was filled with MTA Fillapex using Gutta-percha single cone as a core material. The roots were prepared for SEM evaluation, and serial scanning electron photomicrographs were taken at ×50, ×100, ×500, and ×1000 magnifications. The gaps between the root canal sealer and canal walls were detected and measured in coronal, middle, and apical thirds. For each section, the highest value among the detected gap formations was recorded. Statistical Analysis: Mann-Whitney U-test, Freidman, and Wilcoxon tests were used. Results: The statistical analysis showed no significant difference between two sealers in terms of gap formation (P > 0.05). Conclusions: MTA Fillapex has a similar dentinal wall adaptation ability as AH Plus does. © 2016 Journal of Conservative Dentistry | Published by Wolters Kluwer - Medknow

Postoperative pain intensity after using different instrumentation techniques: A randomized clinical study

Postoperative pain is a frequent complication associated with root canal treatment, especially during apical instrumentation of tooth with preexisting periradicular inflammation Objectives: The aim of this clinical study was to evaluate the influence of the instrumentation techniques on the incidence and intensity of postoperative pain in single-visit root canal treatment. Material and Methods: Ninety patients with single root/canal and non-vital pulps were included. The patients were assigned into 3 groups according to root canal instrumentation technique used; modified step-back, reciprocal, and rotational techniques. Root canal treatment was carried out in a single visit and the severity of postoperative pain was assessed via 4-point pain intensity scale. All the participants were called through the phone at 12, 24 and 48 h to obtain the pain scores. Data were analyzed through the Kruskal–Wallis test. Results: There was significant difference between all groups (p<0.05). The modified step-back technique produced postoperative pain significantly lower than the rotational (p=0.018) and reciprocal (p=0.020) techniques. No difference was found between the reciprocal and rotational techniques (p=0.868). Postoperative pain in the first 12 h period (p=0.763) and in the 24 h period (p=0.147) was not significantly different between the groups. However, the difference in the 48 h period was statistically different between the groups (p=0.040). Conclusion: All instrumentation techniques caused postoperative pain. The modified step-back technique produced less pain compared to the rotational and reciprocal techniques. © 2017, Faculdade de Odontologia de Bauru. All rights reserved.2013-27194235-03This study was supported by the funds of B?lent Ecevit University (grant number: 2013-27194235-03)

Comparison of Nd: YAG and diode laser irradiation during intracoronal bleaching with sodium perborate: Color and raman spectroscopy analysis

Objective: The aim of this study was to evaluate the color and enamel structure changes after intracoronal bleaching with sodium perborate under neodymium:yttrium-aluminum-garnet (Nd:YAG) and diode laser irradiation. Background data: Although some studies investigated the efficacy of laser irradiation during intracoronal bleaching, no study has been conducted to investigate the changes in both color and enamel structure during intracoronal bleaching with laser irradiation. Methods: Thirty-six extracted mandibular incisors were used. The root canals were prepared and filled with AH Plus and gutta-percha. Baseline color values and Raman spectra were obtained from all samples. The samples were randomly divided into three groups as follows: group 1, intracoronal bleaching with sodium perborate plus NdYAG laser irradiation; group 2, intracoronal bleaching with sodium perborate plus diode laser irradiation; and group 3, intracoronal bleaching with sodium perborate without any laser irradiation. Following the bleaching procedures, the final baseline color values and Raman spectra were obtained. The baseline and final values were statistically analyzed. Statistical analyses were performed with SPSS 18.0 software using Anova and the Kruskal-Wallis test. Results: There was a significant difference between the Nd:YAG laser and control groups ( p 0.05). Conclusions: Laser application, especially Nd:YAG laser irradiation, was able to increase the efficacy of intracoronal bleaching with sodium perborate. Laser irradiation significantly increased the bleaching efficacy without any changes in the enamel surface structure. © 2015 Mary Ann Liebert, Inc