Titanium Oxide (TiO2)/Polymethylmethacrylate (PMMA) Denture Base Nanocomposites: Mechanical, Viscoelastic and Antibacterial Behavior

Abstract

Currently, polymethylmethacrylate (PMMA) is the most popular denture base material. Most fractures of dentures that occur during function are due to its insufficient mechanical strength. The major drawbacks of PMMA are insufficient ductility, strength, and viscoelastic behavior. The purpose of this study was to evaluate a polymethylmethacrylate denture base material modified with TiO2 nanoparticles in terms of nanomechanical, creep-recovery, and relaxation. Additionally, the effects of addition TiO2 nanoparticles on the thermal and antimicrobial adhesion behaviors were investigated. Differential scanning calorimetry and thermogravimetric analysis indicated that the effect of small amounts of TiO2 nanoparticles (1 wt. %, 2 wt. %, and 3 wt. %) on the degradation behavior of PMMA denture bases was insignificant. The nanomechanical test results of the PMMA and PMMA/TiO2 nanocomposites indicated that the hardness and modulus in the nanoscale range improved due to TiO2 addition. At a 1200-nm penetration depth, the modulus increased by 10%, 16%, and 29% and hardness increased by 18%, 24%, and 35% with the addition of 1 wt. %, 2 wt. %, and 3 wt. % TiO2, respectively. Furthermore, the creep-recovery and relaxation behaviors of PMMA were significantly improved due to the addition of TiO2. The creep strain decreased from 1.41% to 1.06%, 0.66%, and 0.49% with the addition of 1 wt. %, 2 wt. %, and 3 wt. % TiO2, respectively. The relaxation test results showed that the initial stress under 1% strain improved to 19.9, 21.2, and 22 MPa with the addition of 1 wt. %, 2 wt. %, and 3 wt. % TiO2, respectively. The improvement in the nanohardness, modulus, creep recovery, and relaxation behavior of PMMA due to the addition of TiO2 nanoparticles indicated the role of the nanoparticles in increasing the PMMA matrix stiffness by reducing its mobility and free volume. TiO2 nanoparticles also improved the antimicrobial behavior of PMMA by significantly reducing bacterial adherence with increasing TiO2 ratio.

Behavior of PMMA Denture Base Materials Containing Titanium Dioxide Nanoparticles: A Literature Review

“…Due to the photocatalytic property against microorganisms, patients will be able to maintain the hygiene of their dentures easily by exposing them to solar energy/light sources to activate the TiO 2 NP [11]. On the same way, Alrahlah et al (2018) reported a 50% and 90% decrease in bacterial cell attachment of E. faecalis and P. aeruginosa, respectively, with the mere addition of 3% TiO 2 NP [43]. Likewise, Totu et al (2017) investigated the effect of incorporating TiO 2 NP into a 3D-printed PMMA denture in an attempt to improve denture antimicrobial characteristics and found that even the small addition of 0.4% of TiO 2 NP to PMMA resulted in a nanocomposite that prevented the colonization of microorganisms and further formation of biofilm [24].…”

“…More recently, Alrahlah et al (2018) confirmed the increase in surface hardness of up to 35% with 3% TiO 2 NP addition. The values of the hardness measurements were higher at the surface of the composite resin and decreased as we move inward toward the core of the material, suggesting higher crosslinking at the surface [43]. Regarding selection of the most appropriate concentration of filler for inclusion within denture resin, results of multicriteria decision making (MCDM) method suggested that a filler content in the range of 2wt% would create a composite material with improved mechanical properties including surface hardness [34].…”

Evaluation of nanomaterials to prevent oral Candidiasis in PMMA based denture wearing patients. A systematic analysis

“…Incorporation of silica/titania nanoparticle coating in dental prosthesis significantly reduces microbial adhesion. 32 As TiO 2 ratio increased in PMMA-TiO 2 it improved the antimicrobial behaviour of PMMA by drastically decreasing bacterial adherence. 32−33 The integration of TiO 2 Nanoparticles to PMMA reduces the porosity of the denture bases.…”

Studying the Impact Strength of Layered Denture Base Resin

“…It is not considered as a perfect material because of its bad mechanical and physical properties [1][2][3]. The main drawbacks of poly methyl methacrylate are deficient ductility, viscoelastic behavior and inferior mechanical strength [4][5][6] Rapid and quick development concepts of composite technology promoted the reinforcement of materials utilizing fibers [7][8][9]. Addition of polyethylene, glass and carbon fibers produced a significant increase in the impact strength.…”