Papers by Keyword: Dental Composites

Abstract: Nanotitania is a well-acceptable material in biomedical applications due to its excellent biocompatibility. However, its other performances in terms of physical properties, mechanical properties and specific wear rate have been the keen interest of researchers. The study aims to modify dental composite formulation by adding nanotitania filler in different mass fractions and study to investigate its influence on physical and mechanical properties. A conventional monomer matrix consisting of Bisphenol A-Glycidyl methacrylate (BisGMA), Urethane dimethacrylate (UDMA), Triethylene glycol dimethacrylate (TEGDMA), Camphor Quinone (CO), Ethyl-4-dimethylaminobenzoate (EDMAB) was first added and modified with varying nanotitania filler fractions (0,0.5,1,1.5 wt. %). The performance of newly formulated composites was investigated in four major parameters like apparent porosity, hardness, compressive strength and specific wear rate. All tests are performed as per ISO4049 standard which are requirements for fabrication, characterization, direct/indirect restoration of dental composite, inlays, onlays, veneers, crowns and bridges. Specific wear rate was estimated using pin on disk tribometer under constant load of 20N. Due to its extremely hard and brittle nature, the micro-hardness and compressive strength of resin composite on adding 0.5 wt.-% of nanotitania filler fraction (DC0.5TiO₂) were increased by 68% and 16% respectively. Using a pin on disc tribometer, a wear assessment has been performed and it was found that under constant wear parameters and distilled water environmental conditions, the specific wear rate was decreased by 26 % on adding 0.5 wt.-% mass fraction of nanotitania. Nanotitania indicated excellent performance based on mechanical and wear properties and hence, it can be suggested to use nanotitania as a novel filler of dental composite for the replacement of other non-biocompatible ceramic filler.

Abstract: Tooth cavity is one of the most common dental health problems in Indonesia that can be treated by applying dental fillings. However, dental fillings often experience microcrack and secondary caries. Self-Healing Dental Materials (SHDM) which use microencapsulation technique as healing system, are developed to solve this problem. In this work, we employed mesoporous biosilica from Cyclotella striata TBI as microcapsule to entrap healing liquid contains polyacrylic acid and polybasic carboxylic acid. SHDM was prepared by mixing Filtek Z350XT flowable composite with fluoroaluminosilicate healing powder and healing liquid encapsulated in biosilica. We also added silica containing cetyltrimethyl ammonium bromide (CTAB@PSN) filler as antibacterial agent. Six groups of tested samples were prepared with various composition of biosilica and CTAB@PSN. Filtek composite was used as a control. We studied the entrapment of helaing liquid in biosilica and effect of biosilica addition towards mechanical properties of the resulting SHDM. The statistical analysis was determined using ANOVA. Scanning Electron Microscopy and Fourier Transform Infra-Red showed that the microencapsulation of healing liquid in biosilica was successful with immersion method without stirring. Addition of biosilica and CTAB@PSN fillers into the Filtek composites resulted in the decrease of the mechanical properties. The hardness values of the resulting composites were in the range 44.33–53.25 VHN. Nevertheless, the hardness values were still comparable to the hardness of dentin. Addition of filler decreased the compressive strength, but statistically insignificant, from 268.68 MPa to 228.53–252.04 MPa. To conclude, healing liquid can be entrapped in porous biosilica. Adding healing agent affects SHDM composite’s hardness but not its compressive strength.

Abstract: Human teeth are exposed to various chemical and mechanical factors. From mechanical point of view it includes attrition, abrasion or their combination. Teeth and dental restorative materials are subjected to normal and shear loads. Therefore the contact-based stresses during mastication and teeth wear are of considerable importance. In order to study wear behavior of enamel, dentine and two dental restorative composite materials scratch test at various contact conditions was employed. Hardness and elastic modulus were measured using nanoindentation with spherical and pyramidal indenters. Residual wear tracks were observed using laser scanning confocal microscopy.

Abstract: The aim of this study was to determine the influence of powder fillers on the tribological properties of composite materials used for dental fillings. The investigated composites contain a fluoridated filler (based on Ba-Sr-Al-P-Na-silicate glass fillers) as a fluoride source as well as different powder fillers (friction modifiers) e.g. silicon nitride (Si3N4), boron nitride (BN), polyethylene (PE), polytetrafluoroethylene (PTFE). Composite disks were photo-cured and tested for wear against harder stainless-steel counterface. Wear tests were carried out by means of special tribotester in the presence of phosphate buffer as a lubricant. Influence of the load and filler contents on the friction coefficients and wear were estimated. The interaction between the filler particles and organic matrix and its influence on the tribological behavior of prepared specimens were observed. Organic powder fillers (PE, PTFE) reduced the friction coefficient and the wear of tested composite materials for dental fillings. Inorganic friction modifiers (Si3N4, BN) did not exhibit this effect.

Abstract: Fluoride release from composite materials for dental fillings depending on the type of powder filler and dynamical loading is the main problem considered in the paper. The fillers used for research were fluoridated glass (based on Ba-Sr-Al-P-Na-silicate glass), ytterbium fluoride (YbF3) as a fluoride source and nanosilica. In order to estimate the influence of the usage loading value on fluoride release from analyzed samples, the wear tests were carried out by means of special tribotester in presence of phosphate buffer as a lubricant. After friction processes the fluoride release tests were performed in phosphate buffer using direct potentiometry method with fluoride selective electrode. The fluoride emission was analyzed on the basis of: 1) type and amount of fillers powder, 2) using loading. Surface roughness was also investigated. The surface of each composite was analyzed by means of SEM.