Effect of Fluorohydroxyapatite on Biological and Physical Properties of MTA Angelus.

Objectives: This study aimed to assess the effect of addition of fluorohydroxyapatite (FHI) on biological and physical properties of mineral trioxide aggregate (MTA) Angelus. Materials and Methods: In this in vitro, experimental study, nano-FHI powder was first synthesized, and the morphology and chemical structure of particles were evaluated by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). Three groups were evaluated in this study: MTA Angelus, MTA modified with 10% FHA, and MTA modified with 15% FHA. After mixing, the materials were applied to ring molds (10 mm diameter, 1 mm height), and the setting time of the three groups was evaluated according to ISO6876 and ASTMC266-03 with a Gillmore needle. The pH was measured using a pH meter at 24 and 48 hours and 7 days after mixing. The cytotoxicity of the materials was assessed in freshly mixed form and after 1 and 7 days using the methyl thiazolyl tetrazolium (MTT) assay according to ISO10993-5. Data were analyzed by one-way and repeated measures ANOVA and Tukey's test (alpha = 0.05). Results: The addition of FHA to MTA significantly decreased the initial setting time (P < 0.05) and had no significant effect on cell viability (compared with pure MTA Angelus) at 1 and 7 days. However, modified MTA groups in freshly mixed form showed significantly lower cell viability (P < 0.05). The pH remained alkaline at all time points. Conclusion: Addition of 15% FHA to MTA Angelus decreased its setting time with no adverse effect on cell viability (except for fresh form) or pH.

Penetration ability and microhardness of infiltrant resin and two pit and fissure sealants in primary teeth with early enamel lesions.

To determine the penetration depth and enamel microhardness (EMH) of an infiltrant resin and two fissure sealants in primary teeth with early enamel lesions. We randomly divided 174 sound teeth into six groups (n = 29): (1) phosphoric acid (PA) + Clinpro, (2) PA + Aegis, (3) Icon, (4) hydrochloric acid (HCl) + Clinpro, (5) HCl + Aegis, and (6) control. Percentage penetration (%PP) was analyzed by confocal laser scanning microscopy (n = 15). EMH was measured (n = 12), and the percentage of EMH recovery (%REMH) was calculated. Twelve samples were examined under a scanning electron microscope (SEM). All data were analyzed with the Kruskal-Wallis and one-way ANOVA tests (p < 0.05). Groups 3 and 4 showed the highest %PP (all, p < 0.05). Icon application led to significantly higher %REMH compared to the others (p < 0.05). Groups 2 and 5 showed the lowest reduction in %REMH after pH-cycling. Application of Icon and Clinpro with HCl pretreatment showed the greatest %PP. pH-cycling led to a decrease in %REMH for all of the materials, although this effect was lower in teeth treated with Aegis.

A modified TEGDMA-based resin infiltrant using polyurethane acrylate oligomer and remineralising nano-fillers with improved physical properties and remineralisation potential.

OBJECTIVES: This study aimed to modify an experimental triethylene glycol dimethacrylate (TEGDMA) based resin infiltrant using PUA oligomer and two remineralising fillers, including fluorohydroxyapatite (FHA) and fluoride-doped bioactive glass (FD-BG), to improve the mechanical and physical properties and induce remineralising potential. MATERIALS AND METHODS: The polyurethane acrylate oligomer (PUA) was synthesised and characterised. Experimental resin infiltrant was prepared by mixing 10% of synthesised PUA with 88% TEGDMA. Water contact angle, penetration coefficient, and penetration depth were then measured. The FHA and FD-BG fillers were synthesised and characterised. To prepare nano-filled resin infiltrant, 5% of each powder was mixed with the prepared resin infiltrant. The prepared resin infiltrants were characterised to evaluate their degree of conversion, mechanical properties, water sorption, and solubility. The ion release of filled resin was also assessed. The non-infiltrated and infiltrated enamel specimens underwent fourteen days of pH-cycling, and a surface microhardness was done to assess the resistance to demineralisation. RESULTS: The results showed that the addition of PUA to TEGDMA increased the mechanical properties and decreased water sorption and solubility. The addition of synthesised FD-BG fillers to resin infiltrant significantly improved the resistance to demineralisation of enamel samples compared with other groups (p ≤ 0.001). The FHA fillers also improved the resistance to demineralisation; however, the produced changes were not statistically meaningful (p > 0.05). CONCLUSIONS: Based on the results, the PUA+TEGDMA+ FD-BG/FHA composite can be used as an alternative material for pure TEGDMA in enamel infiltration approaches owing to its better mechanical properties, lower water sorption and solubility, and also remineralisation potential. CLINICAL SIGNIFICANCE: A resin infiltrant with remineralisation potential, lower water sorption and solubility and higher mechanical properties may enhance the management of early caries lesions.

In-vitro bioactivity evaluation and physical properties of an epoxy-based dental sealer reinforced with synthesized fluorine-substituted hydroxyapatite, hydroxyapatite and bioactive glass nanofillers.

The purpose of this study was to evaluate the physical properties and bioactivity potential of epoxy-based dental sealers modified with synthesized bioactive glass (BAG), hydroxyapatite (HA) and fluorine substituted hydroxyapatite (FHA) nanoparticles. The synthesized powders were incorporated at 10% and 20% into the epoxy-based dental sealer. The setting time, flow and solubility and microhardness of the modified and unmodified samples were examined. The bioactivity was evaluated using FESEM-EDX and elemental mapping, ATR-FTIR and XRD. The flow value of all of the experimental groups except the FHA modified samples, was greater than 20 mm. Concerning solubility, no specimens exhibited more than 1% weight loss. The solubility value of the FHA groups was statistically significant lower than other groups (p ≤ 0.001). The mean hardness values of all of the modified samples were significantly higher than the unmodified group (p ≤ 0.001). Regarding bioactivity, in vitro study revealed that after 3 days immersion in SBF a compact and continuous calcium phosphate layer formed on the surface of epoxy sealers containing BAG and HA nanoparticles. Based on these results, the addition of BAG and HA nanoparticles did not adversely alter the physical properties of epoxy sealers. Additionally, they improved the in vitro bioactivity of the epoxy sealer.