Cytocompatibility and cell migration evaluation of calcium silicate-based root canal sealer compared to epoxide-amine resin sealer in stem cells from human apical papilla: An in-vitro study.

The purpose of this study was to assess the effect of a calcium silicate-based sealers (CeraSeal) and an epoxy resin-based sealer (AH Plus) on cytotoxicity and cell migration of stem cell from the human apical papilla (hSCAPs) by using the Alamar Blue, Annexin V-FICT and wound healing assays. In Alamar Blue assay, hSCAPs exposed to undiluted CeraSeal extract had significantly higher cell viability compared with that observed when cells were treated with AH Plus in all experimental period (p < 0.001). The flow cytometry analysis confirmed the comparison on viable cells and indicated that AH Plus increased apoptosis compared to CeraSeal and the control groups (p < 0.001). Additionally, AH Plus exhibited significantly lower level of cell migration than CeraSeal and the control for up to 48 h observation (p < 0.01). In summary, calcium silicate-based sealer (CeraSeal) is less cytotoxic and more biocompatible than epoxy resin-based sealer (AH Plus).

Effectiveness of MTA apical plug in dens evaginatus with open apices.

BACKGROUND: The present study aims to evaluate the effectiveness of mineral trioxide aggregate (MTA) application in treating dens evaginatus affected teeth with apical lesions and open apices using haemostatic collagen membrane to prevent the apical extrusion of MTA. METHODS: Twelve patients with 14 dens evaginatus affected teeth with apical lesions and open apices were treated with MTA apical plug and haemostatic collagen membrane. Clinical symptoms of subjective pain, pain of palpation, percussion, sinus tract, and the apical lesions' radiographic parameter were recorded at every 3-month interval up to 9 months after treatment. Paired t-test or Wilcoxon signed-rank test was used for statistical analysis with P < 0.05 as the threshold for considering results to be statistically significant. RESULTS: No patient experienced clinical symptoms 3 months after endodontic treatment. In addition, there was a significant difference in the dimensions of the apical lesions' before compared to 3 months after endodontic treatment. CONCLUSIONS: The combination of MTA apical plug and haemostatic collagen membrane effectively treated dens evaginatus affected teeth with apical lesions, and open apices.

Differential scanning calorimetric investigations of three rotary nickel-titanium instrument systems before and after simulated clinical uses.

BACKGROUND: The transformation temperatures were important values, influencing the mechanical properties and clinical performance of nickel-titanium instruments. The aim of this study was to determine the transformation temperatures of three rotary nickel-titanium (NiTi) instruments: Reciproc, HyFlex CM Pro, and Neoniti before and after simulated clinical uses. METHODS: Ninety new NiTi instruments of three single-file instruments: Reciproc, HyFlex CM Pro, and Neoniti were divided into three groups. Thirty instruments of each group were divided into 3 subgroups (10 instruments for each subgroup): new, one-time simulated clinical used and sterilised, and three times simulated clinical used and sterilized subgroups. The instruments were in the as-received condition for the new subgroups, one time used in the plastic endo-training blocks and sterilised for the one-time subgroups, and three times used in the plastic endo-training blocks and sterilised for the three times subgroups. Each instrument in subgroups was cut into four small segments of 4-5 mm. All segments of instruments were analysed using Differential Scanning Calorimetry (DSC). Data was collected and analysed using SPSS version 20.0 with ANOVA test or Kruskal-Wallis test at the significant level of 0.05. RESULTS: There was not significant difference between before and after simulated clinical use with sterilised procedure in three NiTi instrument systems. The austenite-finish (Af) temperatures of three instrument systems were higher than that of the human body (37 °C), of these, the Af temperature of Neoniti was highest and that of HyFlex CM Pro was lowest. CONCLUSIONS: The austenite-finish (Af) temperatures of three NiTi instruments were higher than that of human body temperature, therefore, material was in the phase transformation from martensite to austenite, gives the instruments more flexibility when used in the clinical situation.

Endodontic length measurements using cone beam computed tomography with dedicated or conventional software at different voxel sizes.

The aim of this study is to investigate the accuracies and the agreements of the 3D Endo software, conventional CBCT software Romexis Viewer at three voxel sizes, and the EAL ProPex Pixi in endodontic length measurements. Three hundred and twenty-nine root canals in 120 intact human extracted molars were accessed. The actual lengths (AL) and electronic lengths (EL) were measured using the ruler and electronic apex locator (EAL), respectively. Teeth were scanned using the CBCT at different voxel sizes (0.075, 0.10, and 0.15 mm). Root canal lengths were measured using 3D Endo with proposed length (3D-PL) by software, corrected length (3D-CL), Romexis Viewer. The Fisher's exact test, paired t-test and Bland-Altman plots were calculated to detect the agreements of the four methods with AL measurements. The ProPex Pixi measurements obtained the highest accuracy in the range of ± 0.5 mm. There was agreement between the 3D-PL and the 3D-CL with AL measurements at voxel size of 0.15 mm and at voxel size of 0.10 mm, respectively. The CBCT Romexis Viewer measurements agreed with AL at three voxel sizes. The conventional CBCT measurements using Romexis Viewer and dedicated software did not reach to the 100% accuracy in the range of ± 0.5 mm.

Endodontic length measurements using 3D Endo, cone-beam computed tomography, and electronic apex locator.

BACKGROUND: The objective of this study is to investigate the accuracy of the 3D Endo software, cone-beam computed tomography (CBCT) software, and the electronic apex locator (EAL) in endodontic length determination. METHODS: 302 root canals in 111 human extracted molars were chosen. Access cavity was performed, and root canal lengths were measured with a digital caliper for actual length (AL) and EAL for electronic length. Teeth were then scanned using CBCT device at voxel size of 0.10 mm. It measured root canal lengths using the CBCT (Romexis Viewer), 3D Endo for proposed length (3D-PL) and correct length (3D-CL). Mean differences between the four methods with the AL were calculated and compared. Fisher's exact test, paired t-test, Bland-Altman plot were used to test the differences among the experimental modalities in working length determination at the significance of 0.05. RESULTS: The accuracy in the range of ± 0.5 mm of the EAL ProPex II was highest among the experimental modalities, however this method disagreed with the actual length. CONCLUSIONS: The correct working length after adjustment from the semi-automatically length by the 3D Endo software and Romexis Viewer measurements agreed with the AL.

A new method for assessment of nickel-titanium endodontic instrument surface roughness using field emission scanning electronic microscope.

BACKGROUND: To introduce a new method for measurement of surface roughness of the endodontic instrument, before and after instrumentation, using the Field Emission Scanning Electronic Microscope (FE-SEM) combined with the ImageJ software. METHODS: Twenty J-shape resin blocks were divided into two groups, ten blocks of each group. Simulated root canal inside the resin block was 16 mm length, 600 angle of curvature, and radius of 4.5 mm. Ten WaveOne Gold Primary and 10 Reciproc Blue R25 instruments were used for root canal instrumentation. The instruments were scanned before and after instrumentation with special molds made to ensure the same areas at the point located 3 mm from the tips of the instruments using the FE-SEM. These scanned images were analyzed using the ImageJ. The arithmetical mean roughness (Ra), root mean square roughness (Rq), and the average distance between the highest peak and lowest valley in each sampling length (Rz) were calculated by ImageJ for quantitative analyses. The paired-t test was performed to analyze the data using the SPSS 22.0 at the significance of .05. RESULTS: Almost all surface roughness values were decreased. However, these decreases were not statistically significant (P > .05). CONCLUSIONS: The FE-SEM combined with the ImageJ was the reliable and appropriate modality for measurement surface roughness of instruments.

The Accuracy of Endodontic Length Measurement Using Cone-Beam Computed Tomography in Comparison with Electronic Apex Locators.

Introduction: The aim of this in vitro study was to evaluate the accuracy of cone-beam computed tomography (CBCT) and two electronic apex locators (EALs) when measuring the actual length of root canals. Methods and Materials: One hundred and eighty four root canals in 135 extracted anterior and posterior permanent teeth were studied. Root canal curvatures were analyzed on CBCT images, and root canals with curvatures less than 70º were chosen. Root canal length measurements were performed using CBCT, ProPex Pixi, E-Pex Pro, and the actual length (AL). The percentages of the measurements in the range of ±0.5 mm to the AL were compared using Fisher's Exact test. The ICC indices and Bland-Altman plots were used to display the agreement of three devices with the AL measurements. The statistical significance was set at P<0.05. Results: The accuracies of E-Pex Pro and ProPex Pixi (87.5% and 82.6%, respectively) were better than that of CBCT (71.7%) (P<0.05). Conclusion: This in vitro study showed that although the accuracies of the two EALs were at high level, there was no device that had an agreement with the actual root canal length measurement.

Time-Shared Twin Memristor Crossbar Reducing the Number of Arrays by Half for Pattern Recognition.

In this paper, we propose a new time-shared twin memristor crossbar for pattern-recognition applications. By sharing two memristor arrays at different time, the number of memristor arrays can be reduced by half, saving the crossbar area by half, too. To implement the time-shared twin memristor crossbar, we also propose CMOS time-shared subtractor circuit, in this paper. The operation of the time-shared twin memristor crossbar is verified using 3 × 3 memristor array which is made of aluminum film and carbon fiber. Here, the crossbar array is programmed to store three different patterns. When we apply three different input vectors to the array, we can verify that the input vectors are well recognized by the proposed crossbar. Moreover, the proposed crossbar is tested for the recognition of complicated gray-scale images. Here, 10 images with 32 × 32 pixels are applied to the proposed crossbar. The simulation result verifies that the input images are recognized well by the proposed crossbar, even though the noise level of each image is varied from -10 to +10 dB.