Examination of surface porosity of current pulp capping materials by micro-computed tomography (micro-CT) method.

When dental pulp is exposed, it must be covered with a biocompatible material to form reparative dentine. The material used, besides being biocompatible, should have an ideal surface structure for the attachment, proliferation and differentiation of dental pulp stem cells. This study aimed to evaluate the porosity of the microstructures of four pulp capping materials using micro-computed tomography (micro-CT). Biodentine, Bioaggregate, TheraCal and Dycal materials were prepared according to the manufacturer's instructions using 2 × 9 mm Teflon molds. A total of 60 samples, 15 in each group, were scanned using micro-CT. Open and closed pores and the total porosity of the microstructures of the materials were assessed. The findings obtained from the study were analyzed via the Kruskal-Wallis test followed by the Mann-Whitney U test. The porosity of Bioaggregate was significantly higher than that of Biodentine, Dycal and TheraCal in all porosity values. While Biodentine did not show a statistically significant difference in open and total porosity values from either TheraCal or Dycal, closed porosity values of Dycal were significantly higher than those of Biodentine and TheraCal. Because of the affinity of cells to porous surfaces, the pulp capping materials' microstructure may affect the pulp capping treatment's success. From this perspective, the use of Bioaggregate in direct pulp capping may increase the success of treatment.

Forecasting COVID19 Reliability of the Countries by Using Non-Homogeneous Poisson Process Models.

Reliability is the probability that a system or a product fulfills its intended function without failure over a period of time and it is generally used to determine the reliability, release and testing stop time of the system. The primary objective of this study is to predict and forecast COVID19 reliabilities of the countries by utilizing this definition of the reliability. To our knowledge, this study is the first carried out in the direction of this objective. The major contribution of this study is to model the COVID19 data by considering the intensity functions with different types of functional shapes, including geometric, exponential, Weibull, gamma and identifying best fit (BF) model for each country, separately. To achieve the objective determined, cumulative number of confirmed cases are modelled by eight Non-Homogenous Poisson Process (NHPP) models. BF models are selected based on three comparison criteria, including Root Mean Square Error (RMSE), Normalized Root Mean Square Error (NRMSE), and Theil Statistics (TS). The results can be summarized as follows: S-shaped models provide better fit for 56 of 70 countries. Current outbreak may continue in 43 countries and a new outbreak may occur in 27 countries. 50 countries have the reliability smaller than 75%, 9 countries between 75% and 90%, and 11 countries a 90% or higher on 11 August 2021. Supplementary Information: The online version contains supplementary material available at 10.1007/s00354-022-00183-1.

Evaluation of a collagen-bioaggregate composite scaffold in the repair of sheep pulp tissue.

PURPOSE: This study aimed to compare the effects of the collagen-BioAggregate mixture (CBA-M) and collagen-BioAggregate composite (CBA-C) sponge as a scaffolding material on the reparative dentin formation. MATERIALS AND METHODS: CBA-C sponge (10:1 w/w) was obtained and characterized by Scanning Electron Microscopy (SEM) and Mercury Porosimetry. Cytotoxicity of the CBA-C sponge was tested by using the L929 mouse fibroblast cell line. Dental pulp stem cells (DPSCs) were isolated from the pulp tissue of sheep teeth and characterized by flow cytometry for the presence of mesenchymal stem cell marker, CD44. The osteogenic differentiation capability of isolated DPSCs was studied by Alizarin Red staining. The cells were then used to study for the compatibility of CBA-C sponge with cell proliferation and calcium phosphate deposition. The effect of CBA-C sponge and CBA-M on the induction of dentin regeneration was studied in the perforated teeth of sheep for the eight-week period. All the analyses were performed with appropriate statistical hypothesis tests. RESULTS: CBA-C sponge was found to be biocompatible for DPSCs. The DPSCs seeded on the CBA-C sponge were able to differentiate into the osteoblastic lineage and deposit calcium phosphate crystals in vitro. Reparative dentin formation was observed after the second week in the CBA-C sponge applied group. At the end of eight weeks, a complete reparative dentin structure was formed in the CBA-C sponge applied group, whereas necrotic tissue residues were observed in groups treated with the CBA-M. CONCLUSION: CBA-C sponge represents a better microenvironment for reparative dentin formation probably due to maintaining DPSCs and allowing their osteogenic differentiation and thus calcium phosphate deposition.

Association between reverse electrical remodeling and cardiac fibrosis markers in patients with cardiac resynchronization therapy.

OBJECTIVE: Cardiac resynchronization therapy (CRT) induces structural and electrical reverse remodeling of the failing heart. However, the association between native QRS narrowing and cardiac fibrosis markers has not been investigated in patients with an implanted CRT device. METHODS: A total of 41 symptomatic patients diagnosed with systolic heart failure who underwent CRT implantation were included in this study. Electrocardiogram findings and cardiac fibrosis marker levels [galectin-3, growth-differentiation factor-15 (GDF-15) and procollagen III N-terminal propeptide (P3TD)] were collected before and 12 months after initiation of biventricular pacing. Reverse electrical remodeling was defined as a decrease in 12-month intrinsic QRS (iQRS) duration by ≥20 milliseconds after CRT implantation. RESULTS: The median QRS duration decreased from 155 milliseconds (interquartile range [IQR]: 142-178 milliseconds) before CRT to 142 milliseconds (IQR: 130-161 milliseconds) (p=0.001) after 12 months of CRT. According to the predefined criteria, electrical remodeling was detected in 16 (39.0%) patients. The median galectin-3, GDF-15, and P3TD levels were significantly decreased after CRT implantation in patients with electrical remodeling [27.65 ng/mL (IQR: 24.4-35.2 ng/mL) vs 23.00 ng/mL (IQR: 16.0-36.7 ng/mL), p=0.017; 3104 pg/mL (IQR: 2923-4825 pg/mL) vs 2276 pg/mL (IQR: 1294-3209 pg/mL), p=0.002; 0.43 ng/mL (IQR: 0.23-0.64) vs 0.15 ng/mL (IQR: 0.04-0.29 ng/mL), p=0.034, respectively]. The galectin-3, GDF-15, and P3TD levels were not significantly changed in patients without electrical remodeling [26.80 ng/mL (IQR: 23.9-31.5 ng/mL) vs 28.80 ng/mL (IQR: 23.0-34.8 ng/mL), p=0.211; 4221 pg/mL (IQR: 2709-4995 pg/mL) vs 3035 pg/mL (IQR: 2038-4872 pg/mL), p=0.143; and 0.34 ng/mL (IQR: 0.11-0.68 ng/mL) vs 0.21 ng/mL (IQR: 0.09-0.37 ng/mL), p=0.112, respectively]. CONCLUSION: The results from the small sample used in this study indicated that electrical reverse remodeling after CRT was associated with a decrease in cardiac fibrosis.

Cement Thickness of Inlay Restorations Made of Lithium Disilicate, Polymer-Infiltrated Ceramic and Nano-Ceramic CAD/CAM Materials Evaluated Using 3D X-Ray Micro-Computed Tomography.

PURPOSE: To evaluate the marginal and internal cement thicknesses of inlay restorations made of various CAD/CAM materials using 3D X-ray micro-computed tomography (micro-CT) technique. MATERIALS AND METHODS: Caries-free extracted mandibular molars (N = 30) with similar size were randomly assigned to three groups (N = 10 per group). Mesio-occlusal-distal (MOD) cavities were prepared, and inlay restorations were obtained by milling out CAD/CAM materials namely, (a) IPS: monolithic lithium disilicate (control), (b) VE: polymer-infiltrated ceramic, and (c) CS: nano-ceramic using a CAM unit. Marginal and internal cement thicknesses were measured using 3D micro-CT. Data were analyzed using 1-way ANOVA and Tukey's tests (alpha = 0.05). RESULTS: The mean marginal and internal cement thickness were not significant in all inlay materials (p > 0.05). Mean marginal cement thickness (µm) was the lowest for the IPS group (67.54 ± 10.16) followed by VE (84.09 ± 3.94) and CS (95.18 ± 10.58) (p > 0.05). The internal cement thickness (µm) was the lowest in the CS group (54.85 ± 6.94) followed by IPS (60.58 ± 9.22) and VE (77.53 ± 12.13) (p > 0.05). CONCLUSION: Marginal and internal cement thicknesses of MOD inlays made of monolithic lithium disilicate, polymer-infiltrated ceramic, and nano-ceramic CAD/CAM materials were similar and all less than 100 µm, which could be considered clinically acceptable. CLINICAL SIGNIFICANCE: MOD inlays made of different CAD/CAM materials presented similar cement thickness, less than 100 µm.

Cytotoxic effects of bulk fill composite resins on human dental pulp stem cells.

Five bulk fill composite resins, including SDR, Tetric EvoCeram Bulk Fill (TEC), X-trafil (XTF), Sonic Fill (SF), Filtek Bulk Fill (FBF), were used in this study. Human dental pulp stem cells were cultured in 12-well culture dishes (3 × 104 cells per cm(2)) and stored in an incubator at 37°C and 5% CO2 for 1 day. On days 1, 7, 14, and 21 of co-culture, viable cells were measured using a WST-1 assay. Lower cell viability was observed with XTF and SDR bulk fill composite resins compared to the control group during the WST-1 assay. Although bulk fill composite resins provide advantages in practical applications, they are limited by their cytotoxic properties. (J Oral Sci 58, 299-305, 2016).

Evaluating the Efficacy and Safety of Internal Cardioversion with Implantable Cardioverter Defibrillator Device for Atrial Fibrillation in Systolic Heart Failure Patients.

BACKGROUND: Atrial fibrillation (AF) commonly observed in patients with heart failure and cardioversion was often needed to restore the sinus rhythm. Previously, there is no study evaluating usefulness of internal cardioversion with implantable cardioverter defibrillator (ICD) device. In this study, we aimed to compare the efficacy and long-term effects of internal cardioversion with ICD devices compared to conventional external cardioversion in patients with AF and heart failure. METHODS: Seventy patients with AF and heart failure who underwent electrical cardioversion were enrolled in the study. Forty patients (mean age 65.36 ± 10.37, 35 male) were assigned to undergo internal cardioversion with approximately 35 J shocks delivered through the ICD electrode. Standard external cardioversion was performed for the remaining patients (30 patients; mean age 66.20 ± 11.89; 24 male) that were similar with regard to baseline, and electrocardiographic characteristics. RESULTS: Sinus rhythm was restored in 32 of 40 patients (80.0%) assigned to internal cardioversion compared with 25 of 30 patients (83.3%) assigned to external cardioversion (P = 0.725). We did not witness any serious complication during the procedure and hospitalization. On the follow-up, there was no statistically significant difference in recurrence of AF and incidence of major cardiovascular events between the internal and external cardioversion groups. CONCLUSIONS: Internal cardioversion with ICD device is an effective and safe method to restore sinus rhythm in heart failure patients with AF.

Evaluation on shear bond strength of different glass ionomer and hydroxy apatite cements used in ossiculoplasty.

BACKGROUND: Glass ionomer cements (GIC) have been widely used in dentistry for many years. In recent years, GIC have also been used for ossiculoplasty. The bond strength of GIC used in ossiculoplasty and the way they may change over the years in the cementation area are being questioned. The bonding strength of the substance may be of importance for long-term outcomes. AIMS: The aim of this study was to investigate the bond strength of different GIC on ossicles. STUDY DESIGN: In vitro study. METHODS: Twenty ossicles were obtained from patients who had undergone ear surgery. All specimens were randomly divided into four subgroups. All specimens were inserted into a specially designed apparatus for shear bond strength (SBS) testing. The tested materials [Aqua Meron (AM), Aqua Cem (AC), Ketac Cem (KC), and Otomimix CPB (OH)] were prepared and applied according to the manufacturer's instructions. The SBS was tested using a universal testing machine at a crosshead speed of 0.5 mm/min. RESULTS: The mean SBSs were found to be 13.28 MPa, 23.43 MPa, 8.51MPa, and 1.78 MPa for AM, AC, KC, and OH, respectively. AC had the highest SBS, which was statistically significantly different from that of KC and OH (p<0.05). Both AM and KC had higher SBS than OH (p<0.05). CONCLUSION: The results obtained in this study by investigating the bone-bonding strength of cements widely used in ossiculoplasty demonstrate that some of these substances have a greater ability to bond to ossicles compared to others. Further clinical investigations are needed to test different parameters.

Evaluation of the genotoxicity and cytotoxicity in the buccal epithelial cells of patients undergoing orthodontic treatment with three light-cured bonding composites by using micronucleus testing.

OBJECTIVE: This study evaluated the cytotoxicity and genotoxicity of fixed orthodontic treatment with three different light-cured orthodontic bonding composites by analyzing micronucleus (MN) formation in the buccal mucosa during a 6-month period. METHODS: Thirty healthy volunteers were selected from consecutive patients referred for orthodontic treatment. Equilibrium 2 brackets and molar tubes (Dentaurum) were bonded with three different light-cured orthodontic bonding composites-Transbond XT (3M Unitek), Kurasper F (Kuraray Europe), or GrenGloo (Ormco Corporation)- to all teeth in both arches. Exfoliated buccal epithelial cells were scraped from the middle part of the inner cheeks with sterile cement spatulas before treatment and at 1, 3, and 6 months after treatment. MNs and nuclear alterations, such as karyorrhexis (KR), karyolysis (KL), and binucleated cells (BNs), were scored under a light microscope. Repeated measure ANOVA was used to calculate statistical differences in degenerative nuclear abnormalities. RESULTS: MN rates did not significantly differ among different time points within the same cell type (p > 0.05). In contrast, the number of BNs in buccal epithelial cells significantly increased in all composite groups (p < 0.01, Transbond XT; p < 0.001, Kurasper F and GrenGloo). KL frequency significantly increased between the beginning and end of the study in the Kurasfer F (0.80 ± 0.79 to 1.90 ± 1.10; p < 0.05) and GrenGloo (1.30 ± 1.06 to 2.40 ± 1.08; p < 0.05) groups. CONCLUSIONS: After 6 months of fixed orthodontic treatment with different light-cured composites, morphological signs of cytotoxicity were observed but genotoxic effects were absent.

Effectiveness of different irrigation systems on smear layer removal: A scanning electron microscopic study.

OBJECTIVES: To evaluate effectiveness of the apical negative pressure irrigation (EndoVac), passive ultrasonic irrigation (PUI), and conventional needle irrigation (CI) systems on smear layer (SR) removal. MATERIALS AND METHODS: Sixty single-rooted canines were prepared using NiTi rotary files and subjected to different irrigation regimens: EndoVac with NaOCl (Group 1) or NaOCl/EDTA (Group 2); PUI with NaOCl (Group 3) or NaOCl/EDTA (Group 4); CI with NaOCl (Group 5) or NaOCl/EDTA (Group 6). The roots were split longitudinally. SEM images were taken to evaluate the amount of residual SR. RESULTS: In Groups 1, 3, and 5, there was no removal of SR (P > 0.05). The coronal thirds within Groups 2, 4, and 6 were cleaned completely, but the middle and the apical thirds was achieved partially or completely (P > 0.05). CONCLUSION: Regardless of which irrigation system was used, the use of NaOCl alone failed to remove the SR. In NaOCl/EDTA combination groups, the SR was removed partially or completely and no statistical significance. This study demonstrated that in order to remove the SR should be used EDTA solution for final irrigation in the root canal, regardless of the technique in each of the three.

Evaluation of antibacterial effects of pulp capping agents with direct contact test method.

OBJECTIVES: Calcium hydroxide has been used in dentistry as a major capping material having the capacity to introduce the formation of a mineralized dentin bridge, but it has no direct inducing effect to the pulp cells. The purpose of this study was to evaluate the antibacterial properties of three different pulp capping agents using a direct contact test (DCT). MATERIALS AND METHODS: The antibacterial properties of three pulp capping agents were evaluated a DCT. For the DCT, wells (n = 12) of 96-microtiter plates were coated with the tested cements (Dycal, Dentsply, USA; DiaRoot BioAggregate, Diadent, Holland; Calcimol LC, Voco, Germany) and Kalzinol (zinc oxide/eugenol cement, Dentsply, USA) was used as control material. A Lactobacillus casei suspension was placed on the surface of each specimen for 1 h at 37°C. Bacterial growth was monitored for 16 h with a temperature-controlled microplate spectrophotometer. The kinetics of the outgrowth in each well were recorded continuously at 650 nm every 30 min. The data were analyzed by one-way ANOVA, and Tamhane's T2 multiple comparison test. The level of significance was determined as P < 0.05. RESULTS: All pulp capping agents showed an increase in the logarithmic growth rate of L. casei when compared with the control group (P < 0.05). Therefore, all pulp capping agents did not show antibacterial activity. CONCLUSIONS: The tested pulp capping agents haven't got antibacterial properties. Therefore, they should be used carefully when pulp is exposed or only very thin dentin remained over the pulp to avoid bacterial contamination.

Antimicrobial effects of several calcium silicate-based root-end filling materials.

The purpose of this study was to evaluate, in vitro, the antimicrobial effect of iRoot BP, iRoot BP Plus, and mineral trioxide aggregate (MTA) against Entercoccus faecalis and Candida albicans by using direct contact test. The materials were tested immediately after application to the microtiter wells and after setting for 1-day and for 7-days. Ten microliters of microbial suspension was added to each well for direct contact with each material for 1 h at 37°C and 100% humidity. Then fresh media was added and, survival of bacteria and fungi was determined by using 10-fold serial dilution and inoculated onto agar plates. In fresh and 1-day samples all of tested materials showed statistically significant antimicrobial effects compared to control groups (p<0.05). In 7-day samples, there were no significantly differences compared to control groups. MTA, iRoot BP and iRoot BP Plus had similar antimicrobial efficacy against E. faecalis and C. albicans.

Cytotoxicity testing of temporary luting cements with two- and three-dimensional cultures of bovine dental pulp-derived cells.

This study evaluated the cytotoxicity of eugenol-containing and eugenol-free temporary luting cements. For cytotoxicity testing, bovine pulp-derived cells transfected with Simian virus 40 Large T antigen were exposed to extracts of eugenol-containing (Rely X Temp E) and eugenol-free (Provicol, PreVISION CEM, and Rely X Temp NE) temporary luting cements for 24 h. The cytotoxicity of the same materials was also evaluated in a dentin barrier test device using three-dimensional cell cultures of bovine pulp-derived cells. The results of the cytotoxicity studies with two-dimensional cultures of bovine dental pulp-derived cells revealed that cell survival with the extracts of Rely X Temp E, Provicol, PreVISION CEM, and Rely X Temp NE was 89.1%, 84.9%, 92.3%, and 66.8%, respectively. Rely X Temp NE and Provicol showed cytotoxic effects on bovine dental pulp-derived cells (P < 0.05). The results of the dentin barrier test revealed that cell survival with the above-mentioned temporary cement was 101.5%, 91.9%, 93.5%, and 90.6%, respectively. None of the temporary luting cements significantly reduced cell survival compared with the negative control in the dentin barrier test (P > 0.05). Biologically active materials released from temporary luting cements may not influence the dentine-pulp complex if the residual dentine layer is at least 0.5 mm thick.

Heat conductive properties of set root canal sealers.

OBJECTIVE: The aim of this study was to examine the thermal conductivity of five different root canal sealers in vitro. MATERIALS AND METHODS: Sealapex, AH Plus, AH 26, Endomethasone and RoekoSeal root canal sealers were examined. These materials were prepared in accordance with the manufacturer's instructions and applied to standard molds. Three samples of each material were prepared. The samples were kept for 5 days under 37°C conditions. Measurements were taken using a heat conduction unit (P.A. Hilton Ltd. Stockbridge, Hants, UK). The thermal conductivity coefficient was calculated for each sample using the Fourier equation. Coefficients were analyzed statistically by the Kruskal-Wallis test. RESULTS: Significant differences were found for thermal conductivity between some materials (p < 0.05). The conductivity coefficient of AH Plus was found to be higher than those of the other materials (p < 0.05). No statistically significant differences were found between AH 26 and RoekoSeal (p > 0.05) and the conductivity coefficients of these sealers were found to be lower than those of the other materials (p < 0.05). No statistically significant differences were found between Sealapex and Endomethasone (p > 0.05) and the conductivity coefficients of these sealers were found to be lower than that of AH Plus but higher than those of RoekoSeal and AH26 (p < 0.05). CONCLUSIONS: The results showed that root canal sealers functioned as thermal insulators and had different heat-conductive properties that depended on their composition.

Cytotoxicity evaluation of dentin bonding agents by dentin barrier test on 3-dimensional pulp cells.

OBJECTIVE: The aim of this study was to evaluate the effects of 4 dentin-bonding agents on the cell viability of bovine derived cells. STUDY DESIGN: Cytotoxicity of dentin-bonding agents (G-Bond [GB], Adper Prompt Self-Etch [APSE], Clearfil DC Bond System [CDCB], and Quadrant University-1-Bond [UB]) was analyzed with a dentin barrier test device using 3-dimensional (3D) pulp cell cultures. A commercially available cell culture perfusion chamber was separated into 2 compartments using a 500 µm dentin disk. The 3D cultures were placed on a dentin disk and held in place with a special biocompatible stainless steel holder. Test materials were introduced into the upper compartment in direct contact with the cavity side of the dentin disks according to the manufacturer's instructions. Subsequently, the pulpal part of the perfusion chamber containing the cell cultures was perfused with a medium (2 mL/h). After an exposure period of 24 hours, cell survival was determined by using the MTT assay. Statistical analyses were performed using the Mann-Whitney U test. RESULTS: In the dentin barrier test, cell survival rates of UB and CDCB were similar to the control group (P > .05). However, all other tested materials were cytotoxic for the 3D pulp-derived cell cultures (P < .05). CONCLUSIONS: Dentin-bonding agents include biologically active ingredients and may modify pulp cell metabolism when the materials are used in deep cavities in spite of a dentin barrier. If these adhesive agents are used in deep cavities, a biocompatible cavity liner should be used.

Cytotoxic effects of resin-modified orthodontic band adhesives. Are they safe?

OBJECTIVE: To evaluate the cytotoxic effects of three different resin-modified orthodontic band adhesives. MATERIALS AND METHODS: Three resin-modified orthodontic band adhesives (Bisco Ortho Band Paste LC, Multi-Cure Glass Ionomer Band Cement, and Transbond Plus Light Cure Band Adhesive) were prepared and the samples were extracted in 3 mL of Basal Medium Eagle with 10% newborn calf serum for 24 hours. The L929 cells were plated (25,000 cells/mL) in wells of 96-well dishes and maintained in a humidified incubator for 24 hours at 37 degrees C, 5% CO(2), and 95% air. After 24-hour incubation of the cells, the incubation medium was replaced by the immersed medium in which the samples were stored. Then L929 cells were incubated in contact with eluates for 24 hours. The cell mitochondrial activity was evaluated by the methyltetrazolium test. Twelve wells were used for each specimen, and methyltetrazolium tests were applied two times. The data were statistically analyzed using one-way analysis of variance and Tukey Honestly Significantly Different tests. RESULTS: Results with L929 fibroblasts demonstrated that all freshly prepared resin-modified orthodontic band adhesive materials reduced vital cell numbers (P > .05), in comparison to the control group. Our data demonstrate that all materials showed significant cytotoxicity compared to the control group. CONCLUSIONS: The results indicate that all materials showed significant cytotoxicity compared to the control group, and further studies using different test methods are needed for all resin-modified orthodontic band adhesives.

Cytotoxic effects of orthodontic composites.

OBJECTIVES: To evaluate the cytotoxic effects of five different light-cured orthodontic bonding composites. MATERIALS AND METHODS: The orthodontic composites Heliosit Orthodontic (Ivoclar), Transbond XT (3M Unitek), Bisco ORTHO (Bisco), Light Bond (Reliance), and Quick Cure (Reliance) were prepared, and the samples were extracted in 3 mL of BME (Basal Medium Eagle) with 10% newborn calf serum for 24 hours. The L929 cells were plated (25,000 cells/mL) in a 96-well dish and maintained in a humidified incubator for 24 hours at 37 degrees C, 5% CO(2), and 95% air. After 24 hours of incubation of the cells, the incubation medium was replaced by the immersed medium in which the samples were stored. Then, L929 cells were incubated in contact with eluates for 24 hours. The cell mitochondrial activity was evaluated by the methyl tetrazolium (MTT) test. Twelve wells were used for each specimen, and the MTT tests were applied two times. The data were statistically analyzed by one-way analysis of variance (ANOVA) and Tukey HSD tests. RESULTS: Results with L929 fibroblasts demonstrated that except for Transbond XT, freshly prepared composite materials did not reduce vital cell numbers (P > .05) compared with the control group. Our data demonstrate that Transbond XT showed significant cytotoxicity compared with the control group. CONCLUSION: Results indicate that tested orthodontic bonding composites are suitable for clinical application, but that further studies using different test methods are needed for Transbond XT.