A comparison of the remineralizing potential of dental restorative materials by analyzing their fluoride release profiles.

BACKGROUND: The accessibility of the remineralizing ions in teeth's environment is essential for their incorporation into caries-affected dentin. Novel bioglass-reinforced materials capable of releasing fluoride, calcium and phosphates may be particularly useful in the tissue remineralization process. A novel restorative material, ACTIVA BioActive-Restorative (Pulpdent Corp., Watertown, USA), is a hydrophilic resin-modified glassionomer cement (RMGIC) enriched with bioglass particles and fortified with a patented rubberized polymer resin. Its application in restorative dentistry may be significant, promoting remineralization of carious lesions. OBJECTIVES: The aim of the study was to compare the fluoride ion release profiles from a bioglass-reinforced RMGIC, a conventional glass-ionomer cement (GIC) and a nanohybrid restorative polymer resin. MATERIAL AND METHODS: The quantity of fluoride ions released from ACTIVA, Ketac Molar Quick Aplicap and Tetric EvoCeram was assessed using a fluoride-specific electrode. The surface characteristics of the preand post-experimental specimens were studied using a scanning electron microscope (SEM) and confocal microscope. An X-ray powder diffraction (XRD) analysis was additionally used to examine the chemical compositions of the dental materials. RESULTS: The greatest quantity of fluoride ions was freed from the GIC specimens (20.698-54.118 ppm), followed by the bioglass-reinforced RMGIC (from 1.236 to 15.552 ppm) and nanohybrid polymer resin (0.370-1.148 ppm). The pre-experimental specimens of the bioglass-reinforced RMGIC were porous, while the post-experimental specimens were smoother with visible micro-cracks. The XRD analysis of the bioglass particles confirmed that the material was composed mainly of fluoride (27.70 mass%), silicon (15.62 mass%), aluminum (5.91 mass%), and calcium (5.40 mass%). CONCLUSIONS: The fluoride ion release profile of ACTIVA was lower than the GIC Keta Molar Quick Aplicap, but significantly higher than the nanohybrid restorative polymer resin Tetric EvoCeram.

An initial evaluation of cytotoxicity, genotoxicity and antibacterial effectiveness of a disinfection liquid containing silver nanoparticles alone and combined with a glass-ionomer cement and dentin bonding systems.

BACKGROUND: Bacterial reinfection of dental cavities remains an unsolved clinical problem. The search for methods enabling the limitation of the bacterial factor has become the fundamental goal of the dental materials research. Silver nanoparticles (AgNPs) are used as disinfection agents. An incomplete polymerization of the polymer resins combined with AgNPs, along with the increase of the release of the unbound monomers, have been found. OBJECTIVES: The aim of this study was to evaluate the vitality of the human dental pulp stem cells (DPSCs) in response to a disinfection agent containing silver and gold nanoparticles (NPs), different bonding systems, glass-ionomer cement (GIC), and their combinations with the disinfection agent. Also, the influence of these materials both on the secretory function of DPSCs and on their antibacterial properties was established. MATERIAL AND METHODS: Cytotoxicity (MTT assay) and genotoxicity (enzyme-linked immunosorbent assay - ELISA) assays were used in the study. Antibacterial features were assessed with the optical density (OD) measurement of the bacteria (Streptococcus mutans, Streptococcus salivarius and Lactobacillus acidophilus) kept in dental materials. RESULTS: The disinfection liquid proved to be biocompatible. However, it relevantly interfered with the total-etch bonding system in terms of vitality, which may have serious clinical implications. Its combination with the self-etching system was biocompatible, yet it impaired the antibacterial action of the system. An enhancement of antibacterial action of GIC with AgNPs was found. CONCLUSIONS: The disinfection liquid and GIC were biocompatible toward the DPSCs in terms of cytotoxicity and genotoxicity. Simultaneous usage of AgNPs with other dental materials did not affect the biocompatibility of the used materials. The disinfection liquid and GIC acted as antibacterial agents against all studied bacteria species. Used together with GIC and the total-etch bonding system, the disinfection liquid seemed to be efficient toward bacteria, yet it relevantly impaired the antibacterial action of self-etching systems.

The laboratory comparison of shear bond strength and microscopic assessment of failure modes for a glass-ionomer cement and dentin bonding systems combined with silver nanoparticles.

PURPOSE: More than half of the cavity restorations are replaced due to bacterial microleakage. A need for disinfection agents arises. Application of silver nanoparticles (AgNPs) may be beneficial, yet their impact on the adhesives' shear bond strength to dentin remains unknown. METHODS: The aim was to assess the shear bond strength to dentin of different dental materials combined with AgNPs. Failure modes were also examined using SEM/FIB, SEM/EDS and endodontic microscopes. RESULTS: The results showed no impact of AgNPs addition to dental materials in terms of shear bond strength to dentin. A change of the failure mode of the self-etch bonding system, Clearfil SE Bond, combined with AgNPs was observed. The new failure modes depended upon the order of application of the materials onto dentin. CONCLUSIONS: The microscopic evaluation of the samples showed the presence of AgNPs agglomerations gathered on the dentin's surface. AgNPs connection with self-etching dentin bonding system may have a serious clinical impact.