Perspectives for Titanium-Derived Fillers Usage on Denture Base Composite Construction: A Review Article

Abstract

Poly(methyl methacrylate) (PMMA) is an extensively used material in dentistry because of its aesthetics, processability, and reparability. However, PMMA is still far from being ideal in fulfilling the mechanical requirements of prosthesis. PMMA-based denture base polymers exhibit low fracture resistance and radiopacity behavior. Efforts to improve the mechanical and radiopacity properties of denture base materials through inclusion of silica-based fillers are ongoing. Although silane-treated siliceous fillers are commonly used, they are not sufficiently strong. They also exhibit cracks, which either cut through the glass fillers or propagate around the filler particles. This defect occurs when the dental composites are placed in aqueous oral environment because of the hydrolytic degradation of silica-based fillers and silane-coupling agents. The clinical problem of using silanes in adhesion promotion is bond degradation over time in oral environment. In addition, silanes do not bond effectively to nonsilica-based dental restorative materials. This review presents titanium-derived fillers as alternatives to siliceous fillers. Titanate-coupling agents are found to be effective couplers in treating Ti-based fillers because of their chemical compatibility and relatively high stability in aqueous environment.

Review of titanate coupling agents and their application for dental composite fabrication

“…The presence of TCA induced the hydrophobicity of the NBT and enhanced the adhesion between the filler and the PMMA matrix. As stated in our previous work 13) , titanated Ti-based fillers are useful reinforcement in dental composites of resin materials. Thus, the chemical compatibility between the dispersed phase and the coupling agent should be considered.…”

“…The stability of the interface in the oral environment and its ability to transfer stresses between the matrix and filler phases during mastication are particularly significant properties of dental composites. Although silane is a coupling agent that is conventionally used in dentistry, its hydrolytic breakdown and the inefficiency of silanized non-silicabased fillers remain challenging 13,[15][16][17] . These limitations cause failure at the interface and the dissolution and leaching out of components, such as unreacted monomers or fillers, because of hydrolytic instability of the siliceous filler and silanes, thereby leading to inferior mechanical properties and shortened service life of dental restorations 16,18,19) .…”

“…Adding a small amount of titanates can improve bond strength and moisture resistance 11) . Resin composites are widely used in restorative dentistry, and satisfactory clinical performance is largely determined by their resistance to degradation in the oral environment 12,13) . The mechanical properties of resin composites are influenced by their chemical composition and type of environment that they are exposed to.…”

PMMA denture base material enhancement: a review of fiber, filler, and nanofiller addition

“…Accordingly, a titanium coupling agent could be useful for improving the properties of titanium-reinforced PMMA. 60 Incorporation of silanized TiO 2 NPs in PMMA improved the impact strength, transverse strength, and surface hardness of the resin and decreased its water sorption and solubility. Moreover, surface roughness increased with the addition of 3wt% of silanized TiO 2 NPs to acrylic resin.…”

In Vitro Wear Resistance of Nano‐Hybrid Composite Denture Teeth

“…Acrylic teeth were introduced in the 1930s with polymethylmethacrylate (PMMA) the most commonly used. By 1950, almost 98% of all acrylic denture teeth used were PMMA . Acrylic teeth solved some of porcelain denture teeth's problems, including brittleness, ease of contouring custom anatomical form, and chemical bond to denture base; however, excessive wear was still a major concern, since acrylic denture teeth can go through rapid change in occlusal morphology in a short period of time …”