In Vitro Investigation of Gelatin/Polycaprolactone Nanofibers in Modulating Human Gingival Mesenchymal Stromal Cells.

The aesthetic constancy and functional stability of periodontium largely depend on the presence of healthy mucogingival tissue. Soft tissue management is crucial to the success of periodontal surgery. Recently, synthetic substitute materials have been proposed to be used for soft tissue augmentation, but the tissue compatibility of these materials needs to be further investigated. This study aims to assess the in vitro responses of human gingival mesenchymal stromal cells (hG-MSCs) cultured on a Gelatin/Polycaprolactone prototype (GPP) and volume-stable collagen matrix (VSCM). hG-MSCs were cultured onto the GPP, VSCM, or plastic for 3, 7, and 14 days. The proliferation and/or viability were measured by cell counting kit-8 assay and resazurin-based toxicity assay. Cell morphology and adhesion were evaluated by microscopy. The gene expression of collagen type I, alpha1 (COL1A1), α-smooth muscle actin (α-SMA), fibroblast growth factor (FGF-2), vascular endothelial growth factor A (VEGF-A), transforming growth factor beta-1 (TGF-ß1), focal adhesion kinase (FAK), integrin beta-1 (ITG-ß1), and interleukin 8 (IL-8) was investigated by RT-qPCR. The levels of VEGF-A, TGF-ß1, and IL-8 proteins in conditioned media were tested by ELISA. GPP improved both cell proliferation and viability compared to VSCM. The cells grown on GPP exhibited a distinct morphology and attachment performance. COL1A1, α-SMA, VEGF-A, FGF-2, and FAK were positively modulated in hG-MSCs on GPP at different investigation times. GPP increased the gene expression of TGF-ß1 but had no effect on protein production. The level of ITG-ß1 had no significant changes in cells seeded on GPP at 7 days. At 3 days, notable differences in VEGF-A, TGF-ß1, and α-SMA expression levels were observed between cells seeded on GPP and those on VSCM. Meanwhile, GPP showed higher COL1A1 expression compared to VSCM after 14 days, whereas VSCM demonstrated a more significant upregulation in the production of IL-8. Taken together, our data suggest that GPP electrospun nanofibers have great potential as substitutes for soft tissue regeneration in successful periodontal surgery.

Optimized Erbium-Doped Yttrium Aluminum Garnet (Er:YAG) Laser Parameters for the Removal of Dental Ceramic Restorations.

OBJECTIVES: The use of lasers for debonding adhesively luted ceramic restorations is a rather recent oral laser application in dentistry. The removal of all-ceramic restorations in the mouth can often be a troublesome task. A novel method for the debonding of ceramic restorations without damaging the restorations is Er:YAG laser irradiation. The aim of this study was to evaluate the Er:YAG laser for debonding procedures of different dental ceramics and to identify appropriate laser settings. MATERIAL AND METHODS: Lithium disilicate, zirconium-reinforced lithium silicate, feldspatic ceramic, and zirconium dioxide were investigated. Ten ceramic rectangular-shaped specimens with 1 and 2 mm thickness were produced from each material. All specimens were irradiated with four different power settings 1.5; 2.5; 3.5; 4.5 W, pulse duration 50 µs, laser repetition rate 10 Hz, time of irradiation 10 s. The transmitted energy was measured with a powermeter. Additionally the suitability of the Er:YAG laser to remove the adhesively bonded ceramic and the time until loss of retention was evaluated. RESULTS: The transmission rate for 1 and 2 mm platelets was determined for zirconium-reinforced lithium silicate at 54.6%/35.6%, lithium disilicate at 53.2%/35.7%, zirconium dioxide at 40.6%/32.4%, and for the feldspathic ceramic at 19.4%/10.1%. For zirconium-reinforced lithium silicate and zirconium dioxide 2.5 W (250 mJ/10 Hz) was an appropriate energy level for effective debonding. Whereas for lithium disilicate and for feldspathic ceramic, 4.5 W (450 mJ/10 Hz) is required for efficient debonding. CONCLUSIONS: There are differences regarding transmission rates between ceramic types for the Er:YAG laser light and additionally depending on the type of ceramic different energy settings should be used for adequate debonding. Based on our in-vitro experiments we recommend 2.5 W for zirconium-reinforced lithium silicate and zirconium dioxide and 4.5 W for lithium disilicate and feldspatic ceramic. Transmission rates of different ceramic types and varying influences of thicknesses and bonding materials should be considered to adjust the laser parameters during laser debonding of adhesively luted all-ceramic restorations.

The effect of combination treatment of CO2-laser irradiation and tetracalcium phosphate/dicalcium phosphate anhydrate on dentinal tubules blockage: an in vitro study.

The aim of this study was the evaluation of the in vitro efficacy of a carbon dioxide (CO2) laser, a tetracalcium phosphate/dicalcium phosphate anhydrate (TP/DP) desensitizer and the combination of the desensitizer and additional CO2 laser irradiation as a treatment modality for cervical dentin hypersensitivity. A total of 48 dental specimens, prepared from extracted human premolars and molars, were divided into four groups: a control group, a TP/DP desensitizer paste group, a CO2 laser (10.600-nm wavelength) group, and a paste and laser group. The specimens were coated with nail varnish except in the marked area and were then immersed in 2% methylene blue dye for 1 h. The specimens were then washed, dried, and cut longitudinally. Thereafter, photos of 40 dentin specimens were taken and evaluated. The area of penetration was assessed and reported as percentage of the dentin surface area. Additionally eight dental specimens were examined with the aid of a scanning electron microscope and evaluated. Significant differences in the penetration depth were found for all experimental groups compared to the control group. The lowest penetration area was detected in the paste-laser group (16.5%), followed by the laser (23.7%), the paste (48.5%), and the control group (86.2%). The combined treatment of the CO2 laser and a TP/DP desensitizer was efficient in sealing the dentinal surface and could be a treatment option for cervical dentin hypersensitivity.

The response of periodontal cells to kaolinite.

OBJECTIVES: The impact of kaolinite on human periodontal cells is yet unknown. The aim of the study was to assess the response of human periodontal cells to kaolinite. METHODS: Human periodontal cells were treated with kaolinite at reducing concentrations from 30 to 0.0015 mg/mL and with conditioned medium, which was depleted of kaolinite. Cell viability was evaluated with a resazurin-based toxicity assay, Live-Dead staining, and MTT assay and staining. The pro-angiogenic factors vascular endothelial growth factor (VEGF) and interleukin (IL)-6 and IL-8 were quantified via ELISA in periodontal fibroblasts. L-929, a standard cell-line used for cytotoxicity studies, served as control cell line. Composition of kaolinite was verified using energy-dispersive X-ray spectroscopy. RESULTS: Kaolinite in suspension but not in conditioned medium impaired cell viability dose-dependently. VEGF, IL-6, and IL-8 production was not substantially modulated by kaolinite or the conditioned medium in periodontal cells. CONCLUSION: Overall, kaolinite can decrease cell viability dose-dependently while conditioned medium showed no toxic effect. No pronounced impact of kaolinite on VEGF, IL-6, and IL-8 production was observed. This study provided first insights into the impact of kaolinite on human periodontal cells thereby inferring to the basis for the evaluation of kaolinite as a carrier in regenerative dentistry. CLINICAL RELEVANCE: Kaolinite, a clay mineral, is successfully used in medicine due to its favorable properties. Also, applications in conservative dentistry are described. However, the response of oral cells to kaolinite is still unclear. Here, we assessed the impact of kaolinite on human periodontal cells.