Effect of SiO2 Nanoparticles Addition on the Flexural Strength of Repaired Acrylic Denture Base

Abstract

Objective The objective of this study was to evaluate the effect of nano-SiO2 addition on the flexural strength (FS) of repaired acrylic denture base. Materials and Methods Heat-polymerized acrylic resin specimens were fabricated in dimensions of (65 × 10 × 2.5 ± 0.1 mm3 ) and then sectioned and prepared, creating repair gap with butt (90 degrees) and bevel (45 degrees) repair surface designs forming two main groups according to joint design. Further subdivision was done into four groups (n = 10) according to nano-SiO2 concentration: one unmodified group and three modified groups (0.25, 0.5, and 0.75 wt %) in the autopolymerized repair resin. Each pair of a specimen was assembled in a mold and repaired according to manufacturer’s recommendations. Statistical Analysis Three-point bending test was done to measure FS, followed by scanning electron microscope (SEM) examination for fracture surface analysis. Data were analyzed using ANOVA and Tukey’s post hoc test (α = 0.05). Results The addition of nano-SiO2 significantly improved FS of repaired acrylic resin in comparison to the unmodified group (p ˂ 0.05). For butt joint, significant differences between nano-SiO2 reinforced groups were noticed (p ˂ 0.05), while reinforced beveled groups did not differ significantly (p ˃ 0.05). Bevel design remarkably increased FS compared with butt design per respective filler concentration. From the SEM images, improved FS was presented with a homogeneous distribution of nano-SiO2 within polymethyl methacrylate. Conclusion Nano-SiO2 addition to repair resin and 45 degree-beveled repair surface increased FS of repaired acrylic resin.

Prosthodontic Applications of Polymethyl Methacrylate (PMMA): An Update

“…Therefore, good mechanical properties are required for the functional performance of denture base materials (biofunctionality). Considering the significance of the mechanical properties, several modifications have been reported for various mechanical properties of PMMA, including its flexural strength [ 14 , 30 , 33 , 68 , 134 , 135 , 136 ], impact strength [ 14 , 137 , 138 , 139 , 140 ], fracture toughness [ 141 , 142 , 143 ], and surface hardness [ 67 , 98 , 141 , 144 , 145 ]. The flexural strength (also known as the modulus of rupture or transverse strength) is assessed using a 3-point bending test according to the guidelines of ISO 20795-1 [ 81 ].…”

“…Ideally, the denture base should have a high flexural strength to bear the complex forces of mastication without permanent deformation or fracture [ 9 ]. A number of studies have investigated [ 14 , 30 , 33 , 68 , 134 , 135 , 136 ] flexural strength using various methods and types of PMMA. Barbrosa et al [ 146 ] reported good flexural strength for heat-cured, cold-cured, and microwave-cured PMMA (92.84 ± 4.73, 84.40 ± 1.68, and 109.63 ± 5.31 MPa, respectively).…”

“…Although there are a number of concerns associated with using PMMA, such as the fracture of dentures due to water sorption and poor impact and flexural strength, the ongoing research has introduced a variety of modifications to overcome and further improve its properties (such as its conductivity, water sorption, solubility, impact and flexural strengths). For example, several studies reported the improvement of PMMA materials while reinforced using a variety of fibers [ 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 ], nanoparticles [ 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 ], and nanotubes [ 38 , 39 , 40 , 41 , 42 ]. Similarly, PMMA-based biocomposites with the addition of epoxy resins, polyamide, or butadiene styrene have been reported to improve the impact strength of PMMA [ 43 ].…”

Effect of Incorporation of Silver Nanoparticles on the Tensile Bond Strength of a Long term Soft Denture Liner

“…[28][29][30][31] Soft liners are even more susceptible to plaque accumulation and fungal infection than hard liners and acrylic denture bases. [5][6][7][8] To prolong the clinical longevity of these materials and reduce the possibility of biofilm accumulation, several solutions have been suggested. 1,11,32,33 Researchers have attempted to add antimicrobial and antifungal agents to the composition of liners.…”

“…6,7 Addition of low concentrations of nano-SiO 2 to acrylic denture base was reported to be a promising method for improving denture longevity and repair strength. 8 The SNPs' incorporation within the acrylic denture base material was even stated to improve its viscoelastic properties. 9 Adequate bonding of soft liners to the acrylic denture bases is essential to ensure their performance.…”