Influence of the Physical Inclusion of ZrO2/TiO2 Nanoparticles on Physical, Mechanical, and Morphological Characteristics of PMMA-Based Interim Restorative Material

Abstract

Polymethyl methacrylate (PMMA) is often used in restorative dentistry for its easy fabrication, aesthetics, and low cost for interim restorations. However, poor mechanical properties to withstand complex masticatory forces are a concern for clinicians. Therefore, this study aimed to modify a commercially available PMMA-based temporary restorative material by adding TiO₂ and ZrO₂ nanoparticles in different percentages as fillers and to investigate its physio-mechanical properties. Different percentages (0, 0.5, 1.5, and 3.0 wt%) of TiO₂ and ZrO₂ nanoparticles were mixed with the pristine PMMA resin (powder to liquid ratio: 1 : 1) and homogenized using high-speed mixer. The composites obtained were analyzed for their flexural strength (F.S.), elastic modulus (E.M.), Vickers hardness (H.V.), surface roughness Ra, morphology and water contact angle (WCA). The mean average was determined with standard deviation (SD) to analyze the results, and a basic comparison test was conducted. The results inferred that adding a small amount (0.5 wt%) of TiO₂ and ZrO₂ nanoparticles (NPs) could significantly enhance the physio-mechanical and morphological characteristics of PMMA interim restorations. EM and surface hardness increased with increasing filler content, with 3.0 wt.% ZrO₂ exhibiting the highest EM (3851.28 MPa), followed by 3.0 wt.% TiO₂ (3632.34 MPa). The WCA was significantly reduced from 91.32 ± 4.21° (control) to 66.30 ± 4.23° for 3.0 wt.% ZrO₂ and 69.88 ± 3.55° for 3.0 wt.% TiO₂. Therefore, TiO₂ and ZrO₂ NPs could potentially be used as fillers to improve the performance of PMMA and similar interim restorations.

Figure 1

Schematic diagram of the preparation of PMMA (TiO₂/ZrO₂) disk and bar specimens.

Figure 2

Surface roughness and topographic images of TiO₂/Trim composites: (a) pristine PMMA, (b) 0.5-TiO₂, (c) 1.5-TiO₂, and (d) 3.0-TiO_2.

Figure 3

Surface roughness and topographic images of ZrO₂/Trim composites: (a) pristine PMMA, (b) 0.5-ZrO₂, (c) 1.5-ZrO₂, and (d) 3.0-ZrO₂.

Figure 4

Flexural strength (a) and elastic modulus (b) of the pristine and modified PMMA composite groups.

Figure 5

Vickers hardness values of the pristine and modified PMMA composite groups.

Figure 6

Water contact angle of the pristine and modified PMMA composite groups.

Figure 7

Scanning electron microscopy (SEM) images of fractured surface: (a) pristine PMMA, (b) 0.5-TiO2, (c) 1.5-TiO2, (d) 3.0-TiO2, (e) 0.5-ZrO2, (f) 1.5-ZrO2, and (g) 3.0-ZrO2.