Advisory Committee Chair
John O Burgess
Advisory Committee Members
Jack E Lemons
Date of Award
Degree Name by School
Master of Science in Dentistry (MScD) School of Dentistry
Dental composites are important in the spectra of restorative materials. Ability to match the color of natural dentition is an appealing characteristic of composite restorations. Additionally, they can be bonded physically to the tooth, which limits the amount of tooth preparation required and thereby conserves healthy tooth structure. In relation to other restorations like amalgams, non-metallic compositions of dental composites have exhibited good biocompatibility. The dental composites are composed of a resin matrix containing a blend of bis-GMA (bis-phenol A-glycidyldimethacrylate) or urethane dimethacrylate (UDMA) along with TEGDMA (tetraethylglycidylmethacrylate). Novel techniques for the reinforcement of these resin-based composites continue in a research and development phase, since the existing resin-filler systems may not be suitable for long term applications in large restorations. The nanofillers reinforced composite resins had shown promising results. Silica-based nanoparticles and clusters are blended with larger-sized fillers and are available commercially for restoring large posterior restorations. These nanoparticles, offer poor crack blunting ability due to their shape and very small diameters and also improves the stiffness of the composites. However, addition of fibers, by virtue of their geometry and very large aspect ratios, may provide better resistance to fracture. The objective of this study was to study the effect of silica nanofiber (SNF) and a mixture of Silica filler particles (SFP) reinforcement on the fracture toughness, flexural strength, three body wear, polymerization shrinkage, rheology, gloss and degree of conversion of bis-GMA/TEGMA based composite resin. Silica nanofibers (SNF) were fabricated using electrospinning and incorporated 20wt %, 35.8wt% and mixture of 20 wt% of SNF and SFP in ratio of 1:1 (20wt% H), into a bis-GMA/TEGDMA matrix. Experimental groups composed of clear resin and traditionally filled flowable resin (PermaFlo, Ultradent) were tested as negative and positive controls respectively. Data were analyzed using one way ANOVA and Tukey's test. Experimental group with 20 wt% of SNF and SNP mixture showed highest fracture toughness, flexural strength, wear resistant, degree of conversion. 20wt% showed highest gloss and 35.8wt% showed best rheological properties. Significant increase in all tested properties (p<0.001) was seen after addition of nanofiber.
Singhal, Shashikant, "Effect Of Different Percentages Of Silica Nanofibers Filler Loads On Mechanical And Physical Properties Of Flowable Composite Resins" (2011). All ETDs from UAB. 2982.