In vitro cytotoxic evaluation of novel fast-setting calcium silicate cement compositions and dental materials using colorimetric methyl-thiazolyl-tetrazolium assay

Bond strength of resin-based restorative materials to fast-setting calcium silicate cement using different resin adhesive systems

This study assessed the bond strength of resin-based restorative materials to fast-setting calcium silicate cement (Aarhus Uinversity, Denmark) when treated with each of two one-bottle universal adhesive systems. The cement surface (N = 256) was treated with a self-priming adhesive and a self-etch phosphate monomer-containing adhesive with and without etching of the cement surface. Specimens then received either resin composite or compomer restorative materials (n = 32). The bond strength was measured after 1 day and 1500 thermocycles (n = 16). The failure type was visually inspected. The cement-adhesive-restorative material interface was visualized using scanning electron microscopy (SEM). The data were analyzed using multiple linear regression. Restorative material type, resin adhesive system, and thermocycling had a statistically significant effect on the bond strength. Compomer restorative material and self-etch universal adhesive system demonstrated statistically significantly higher bond strength values to fast-setting calcium silicate cement, predominantly exhibiting cement cohesive failure. Etching the cement surface enhanced the bond strength of the self-priming universal adhesive. Thermocycling significantly reduced the bond strength. SEM showed self-etch universal adhesive seemingly diffused over the etched cement surface compared to other groups. Self-etch phosphate monomer-containing universal adhesive and compomer resulted in the highest bond strength to fast-setting calcium silicate cement.

Toxicity of resin-matrix cements in contact with fibroblast or mesenchymal cells

The main aim of this study was to perform an integrative review on the toxic effects of resin-matrix cements and their products in contact with fibroblasts or mesenchymal cells. A bibliographic search was performed on PubMed using the following search terms: "cytotoxicity" AND "fibroblast" OR "epithelial" OR "mesenchymal" AND "polymerization" OR "degree of conversion" OR "methacrylate" OR "monomer" AND "resin cement" OR "resin-based cement". The initial search in the available database yielded a total of 277 articles of which 21 articles were included in this review. A decrease in the viability of mouse fibroblasts ranged between 13 and 15% that was recorded for different resin-matrix cements after light curing exposure for 20 s. The viability of human fibroblasts was recorded at 83.11% after light curing for 20 s that increased up to 90.9% after light curing exposure for 40 s. Most of the studies linked the highest toxicity levels when the cells were in contact with Bis-GMA followed by UDMA, TEGDMA and HEMA. Resin-matrix cements cause a cytotoxic reaction when in contact with fibroblasts or mesenchymal cells due to the release of monomers from the polymeric matrix. The amount of monomers released from the resin matrix and their cytotoxicity depends on the polymerization parameters.

Er-Based Luminescent Nanothermometer to Explore the Real-Time Temperature of Cells under External Stimuli

Temperature as a typical parameter, which influences the status of living creatures, is essential to life activities and indicates the initial cellular activities. In recent years, the rapid development of nanotechnology provides a new tool for studying temperature variation at the micro- or nano-scales. In this study, an important phenomenon is observed at the cell level using luminescent probes to explore intracellular temperature changes, based on Yb-Er doping nanoparticles with special upconversion readout mode and intensity ratio signals (I₅₂₅ and I₅₄₅ ). Further optimization of this four-layer core-shell ratio nanothermometer endows it with remarkable characteristics: super photostability, sensitivity, and protection owing to the shell. Thus this kind of thermal probe has the property of anti-interference to the complex chemical environment, responding exclusively to temperature, when it is used in liquid and cells to reflect external temperature changes at the nanoscale. The intracellular temperature of living RAW and CAOV3 cells are observed to have a resistance mechanism to external stimuli and approach a more favorable temperature, especially for CAOV3 cells with good heat resistance, with the intracellular temperature 4.8 °C higher than incubated medium under 5 °C environment, and 4.4 °C lower than the medium under 60 °C environment.

Vital pulp therapy following pulpotomy in immature first permanent molars with deep caries using novel fast-setting calcium silicate cement: A retrospective clinical study

OBJECTIVES

To compare the success rate of vital pulp therapy following complete pulpotomy in immature first permanent molars, during caries treatment, using novel fast-setting calcium silicate cement (Novel CSC) versus MTA.

METHODS

Six- to eight- years old children, who received pulpotomy of first immature permanent molar using one layer novel CSC (Protooth) or two layers slow-setting MTA (MTA Angelus) covered with glass ionomer were recalled for radiographic and clinical evaluation after two years. The effects of cement type, age, gender, jaw, anesthesia type, and restoration type were assessed on the clinical success of pulpotomy and continued root formation (apexogenesis) as the treatment outcome.

RESULTS

Out of 366 included teeth in the study, 316 teeth were available for statistical analysis. The mean observation time was 28.2 ± 2.7 months. Novel CSC showed significantly higher clinical success rate (93.1%) compared to MTA (84.5%). Restored teeth with stainless steel crowns after pulpotomy and treatments performed under general anesthesia had a statistically significant effect on treatment outcome in contrast to age, gender, and jaw type.

CONCLUSION

The observations of this retrospective study suggested that the success rate of vital pulp therapy following complete pulpotomy using one layer fast-setting novel CSC was significantly higher than slow-setting MTA covered with glass ionomer. Treatment under general anesthesia and restoration using stainless steel crowns influenced the treatment outcome.

CLINICAL SIGNIFICANCE

Novel fast-setting calcium silicate cement is a promising new biomaterial for vital pulp therapy in immature permanent molars that allows complete root formation overtime with apexogenesis. Clinicians must also be aware of the importance of immediate definitive restoration and proper sealing and isolation in vital pulp therapy.

Biological Characteristics and Odontogenic Differentiation Effects of Calcium Silicate-Based Pulp Capping Materials

We compared calcium silicate-based pulp capping materials to conventional calcium hydroxide in terms of their biological properties and potential effects on odontogenic differentiation in human dental pulp stem cells (hDPSCs). We cultured hDPSCs on disks (7-mm diameter, 4-mm high) of ProRoot MTA (Dentsply Tulsa Dental Specialties), Biodentine (Septodont), TheraCal LC (Bisco), or Dycal (Dentsply Tulsa Dental Specialties). Cell viability was assessed with cell counting (CCK) and scanning electron microscopy (SEM). Odontogenic activity was assessed by measuring alkaline phosphatase (ALP) activity and gene expression (quantitative real-time PCR). CCK assays showed that Dycal reduced cell viability compared to the other materials (p < 0.05). SEM showed low and absent cell attachment on TheraCal LC and Dycal disks, respectively. hDPSCs exposed to TheraCal LC and Dycal showed higher ALP activity on day 6 than the control group (p < 0.05). The day-9 Runx2 expression was higher in the ProRoot MTA and TheraCal LC groups than in the control group (p < 0.05). On day 14, the ProRoot MTA group showed the highest dentin sialophosphoprotein levels (not significant; p > 0.05). In conclusion, various pulp capping materials, except Dycal, exhibited biological properties favorable to hDPSC viability. ProRoot MTA and TheraCal LC promoted higher Runx2 expression than Biodentine. Future studies should explore the odontogenic potential of pulp capping materials.

GuttaFlow® Bioseal Cytotoxicity Assessment: In Vitro Study

The sealers used for root canal treatment should be biocompatible for the peri-radicular tissues, to evaluate the cytotoxic effects of GuttaFlow® bioseal sealer and to compare them with AH26® epoxy resin. Culture media were conditioned with the GuttaFlow® bioseal and AH26® pellets. MDPC-23 odontoblast cell cultures were treated with conditioned medium and serial dilutions. To evaluate the metabolic activity and cellular viability, the MTT and SRB assays were performed. To determine the production of reactive oxygen species, the DHE and DCF-DA probes were used. Cell cycle and cell-death types were assessed by cytometry, and to evaluate the mineralization capacity, the Alizarin Red S coloration was used. Statistical analysis was performed using analysis of variance (ANOVA) when normality was found and Kruskal-Wallis on the opposite case. For the comparison with normality values, the Student t-test was used. Cells exposed to the GuttaFlow® bioseal conditioned medium maintained high metabolic activities, except at higher concentrations. Likewise, viability was maintained, but a significant decrease was observed after exposure to the highest concentration (p < 0.001), associated with cell death by late apoptosis and necrosis. When cell cultures were exposed to AH26®, metabolic activity was highly compromised, resulting in cell death. An imbalance in the production of peroxides and superoxide anion was observed. GuttaFlow® bioseal showed higher biocompatibility than AH26®.

Biocompatibility and Bioactivity of Set Direct Pulp Capping Materials on Human Dental Pulp Stem Cells

In this study, we assessed the biocompatibility and bioactivity of various pulp capping materials—ProRoot MTA (Dentsply Tulsa Dental Specialties), Biodentine (Septodont), TheraCal LC (Bisco), and Dycal (Dentsply Caulk)—on human dental pulp stem cells (hDPSCs). Experimental disks (diameter, 7 mm; height, 4 mm) were stored in a humified incubator at 37 °C for 48 h. Then, the pulp capping materials were tested for cytotoxic effects by methyl-thiazoldiphenyl-tetrazolium and scratch wound healing assays, and for mineralization potential by Alizarin red S (ARS) staining assay and alkaline phosphatase enzyme (ALP) activity. Cell viability and cell migration did not significantly differ between ProRoot MTA, Biodentine, and control (p > 0.05). TheraCal LC exhibited slower cell migration on days 2–4 compared to control (p < 0.05), and Dycal showed no cell migration. ALP activity was highest with Biodentine on days 10 and 14, and was lowered with TheraCal LC and Dycal (p < 0.05). In the ARS assay, hDPSCs grown in ProRoot MTA and TheraCal LC eluates showed significantly increased mineralized nodule formation on day 21 compared to Biodentine, Dycal, and control (p < 0.05). These findings indicate that ProRoot MTA, Biodentine, and TheraCal LC exhibit better biocompatibility and bioactivity than Dycal.

Bond strength between dentine and a novel fast-setting calcium silicate cement with fluoride

The aim of this study was to evaluate the dentine bond strength of a novel fast-setting calcium silicate cement (Protooth) versus a calcium hydroxide-based cement (Dycal), a calcium silicate cement (ProRoot MTA), and a glass ionomer cement (Ketac-Molar). Mid-root dentine slices of 1 mm thickness were obtained from human maxillary incisors. After enlarging the lumen of the canal to 1.3 mm, the cavities were randomly filled with test materials. Samples were immersed in physiological-like solution. The push-out bond strength was tested on days 1, 28, and 180 (n = 12). Failure types of bonding were determined using a stereomicroscope. We analysed the data using linear regression. Dycal and day 1 were considered as reference for cement type and assessment time, respectively. Protooth, Ketac-Molar, and ProRoot MTA demonstrated higher push-out bond strength than Dycal. The push-out bond strength in the Protooth group increased on day 28 and 180. The bond strength of Ketac-Molar was significantly reduced on day 28. Dycal showed a significant decrease in bond strength on day 180 compared with that on day 1 and 28. Mixed failure was the dominant failure type. Protooth bonding to dentine was increased with time, in contrast to that of ProRoot MTA, Dycal, and Ketac-Molar, as a function of time.

Direct pulp capping of primary molars using a novel fast-setting calcium silicate cement: a randomized clinical trial with 12-month follow-up

Objective: Novel fast-setting calcium silicate cement with fluoride (Protooth) has been developed for potential applications in tooth crowns. The aim of this study was to evaluate the success rate of direct pulp capping in primary molars using two-layer mineral trioxide aggregate (MTA) and overlying glass ionomer cement versus one-layer novel calcium silicate cement with 4 to 10 minutes setting time. Materials and methods: Ninety bilaterally symmetrical primary molars in the same jaw in 45 patients aged 5 to 7 years were included. Exposed pulps following caries removal were randomly capped with one-layer novel calcium silicate cement or two-layer MTA and glass ionomer cement. All cavities were filled with amalgam. Clinical and radiographic evaluations were performed after six and twelve months. 41 patients were available for the evaluations at the end of the 12-month follow-up. Results: The overall success rate of direct pulp capping, in a split-mouth design, using MTA covered with glass ionomer cement or one-layer novel calcium silicate cement after 12 months were 90% (37 out of 41 cases) and 85% (35 out of 41 cases), respectively, without statistically significant differences after 6 and 12 months. Conclusion: Within the limitations of this study, clinical and radiographic evaluations suggested one-layer novel calcium silicate cement would be successfully used in direct pulp capping of primary molars as a practical alternative to two-layer MTA and overlying glass ionomer cement.

In Vitro Evaluation of the Biological Effects of ACTIVA Kids BioACTIVE Restorative, Ionolux, and Riva Light Cure on Human Dental Pulp Stem Cells

This study aimed to analyze the biological effects of three new bioactive materials on cell survival, migration, morphology, and attachment in vitro. ACTIVA Kids BioACTIVE Restorative (Pulpdent, Watertown, MA, USA) (Activa), Ionolux (Voco, Cuxhaven, Germany), and Riva Light Cure UV (SDI, Bayswater, Australia) (Riva) were handled and conditioned with a serum-free culture medium. Stem cells from human dental pulp (hDPSCs) were exposed to material extracts, and metabolic activity, cell migration, and cell morphology were evaluated. Cell adhesion to the different materials was analyzed by scanning electron microscopy (SEM). The chemical composition of the materials was evaluated by energy-dispersive X-ray (EDX). One-way analysis of variance followed by a Tukey test was performed (p < 0.05). Ionolux promoted a drastic reduction in metabolic activity and wound closure compared to the control (p < 0.05), whereas Activa induced adequate metabolic activity and cell migration. Moreover, SEM and immunofluorescence analysis showed abundant cells exposed to Activa. The materials showed different surface morphologies, and EDX spectra exhibited different peaks of C, O, Si, S, Ca, and F ions in glass ionomer cements. The results showed that Activa induced cell migration, cell attachment, and cell viability to a greater extent than Riva and Ionolux.

Clinical and Histological Study on Direct Pulp Capping With CO2 Laser Irradiation in Human Teeth

The study aimed to histologically evaluate wound healing of exposed human pulp on direct pulp capping using super-pulsed CO₂ laser preirradiation. In this single-blind clinical trial, 28 third molar teeth of 17 volunteers were randomly capped with either CO₂ laser irradiation (n=14) or Dycal (calcium hydroxide cement; n=14) and restored using resin composite. The laser was operated in super-pulsed mode (pulse duration, 0.2 ms; interval, 5.8 ms; 0.003 J/pulse). The irradiation conditions were a power output of 0.5 W, an irradiation time of 15 seconds, repeat mode (10-ms irradiation and 10-ms intervals, for a total beam exposure time of 7.5 seconds), total applied energy of 3.75 J, and an activated air-cooling system. Each tooth was extracted at six or 12 months posttreatment and prepared for histological evaluation. We evaluated the parameters of pulp tissue disorganization, inflammatory cell infiltration, reparative dentin formation (RDF), and bacterial penetration. There were no significant differences between groups for all parameters at each postoperative period (Mann-Whitney U-test, p>0.05). CO₂ laser irradiation completely controlled bleeding and exudate from the exposed pulp. The CO₂ laser group had a tendency to delay RDF compared with the Dycal group, but 4 of 7 teeth from the CO₂ laser group showed a complete dentin bridge at 12 months posttreatment.

Histopathological findings of an exposed human pulp carbonised by CO2 laser irradiation: A case report

This report shows the healing process of an exposed pulp carbonised by CO₂ laser irradiation prior to the application of a capping material. Six intact teeth from four volunteers were irradiated by CO₂ laser and randomly capped with either an adhesive resin (SE bond) (n = 3) or calcium hydroxide-based cement (Dycal) (n = 3). The laser was operated in super-pulsed mode (power output, 0.5 W) for an irradiation time of 30 s. All cavities were restored with composite resin. Each tooth was extracted at approximately 30, 50 or 260 days post treatment and prepared for histological evaluation. CO₂ laser irradiation controlled exudate and bleeding from each exposed pulp. Histological images revealed Dycal promoted complete dentine bridge formation at the carbonised pulp surface, and laser energy affected not only the pulp surface but also the deeper part of the pulp chamber.

Delayed replantation of an avulsed immature permanent incisor and apexification using a novel fast-setting calcium silicate cement containing fluoride: a 3-year follow-up case report

BACKGROUND

Traumatic tooth avulsion requires an urgent intervention to replant the tooth. Prolonged post-injury dry extra-oral conditions worsen the prognosis and increase the risk of root resorption. Fluoride has the potential to delay replacement resorption. Calcium silicate cements (CSC) are used to seal the root canal system and to stimulate periapical regeneration in immature open apex teeth (apexification). This report suggests the application of a novel fast-setting CSC with fluoride for apexification in an attempt to hinder root resorption.

CASE REPORT

A delayed replantation of an avulsed open apex permanent central incisor after 75 h of storage in a dry condition in a 6-year-old girl. Standard treatment guidelines for avulsed immature permanent teeth were followed. After tooth replantation a novel fast-setting, CSC containing fluoride was used for apexification.

FOLLOW-UP

The radiographic and clinical evaluations over a period of 3 years demonstrated periodontal bone healing without root resorption, mobility, and ankylosis and an acceptable periapical tissue tolerance to the novel CSC. However, a longer follow-up period is needed.

CONCLUSIONS

Delayed replantation of the avulsed open apex permanent incisor after 75 h of storage under dry conditions and apexification with a novel fast-setting CSC showed a successful outcome after 3 years. Novel CSC with fluoride demonstrated an acceptable biocompatibility and tissue tolerance.

ZnO nanoparticle-embedded silk fibroin–polyvinyl alcohol composite film: a potential dressing material for infected wounds

A highly effective composite film based on ZnO NPs, silk fibroin and PVA for an infected wound.