The accumulation of bacteria at the margin of dental resin composites is the main reason for secondary caries, which may further cause failure of prosthodontics. Therefore, antibacterial activity is highly required. However, the addition of antibacterial agents or fillers weakens the mechanical or aesthetic properties of composites. In this work, regular-shaped SiO2-ZnO complex clusters (CCs) constructed by spray-drying technology can enhance the antibacterial activity while maintaining the mechanical and aesthetic properties of dental resin composites. The results show that the regular shape and closely packed structure of nanoparticle clusters were not corrupted by the introduction of ZnO particles. As compared to resin composites filled with SiO2 nanoparticle clusters, the comprehensive performances of composites containing SiO2-ZnO CCs were further improved, and the composites filled with 70 wt% Si66Zn4 (CCs composed of 66/70 SiO2 and 4/70 of ZnO) exhibited superior antibacterial capability (antibacterial ratio >99.9%) and acceptable depth of cure, degree of conversion, and biocompatibility. The cooperation of different fillers is highly essential for resin composites to achieve enhanced multifunctional performance.

Antibacterial activity and reinforcing effect of SiO2-ZnO complex cluster fillers for dental resin composites.

Biofilm formation on restorative materials and resin composite cements

UNLABELLED Noncarious cervical lesions are highly prevalent and may have different etiologies. Regardless of their origin, be it acid erosion, abrasion, or abfraction, restoring these lesions can pose clinical challenges, including access to the lesion, field control, material placement and handling, marginal finishing, patient discomfort, and chair time. This paper describes a novel technique for minimizing these challenges and optimizing the restoration of noncarious cervical lesions using a technique the author describes as the class V direct-indirect restoration. With this technique, clinicians can create precise extraoral margin finishing and polishing, while maintaining periodontal health and controlling polymerization shrinkage stress. CLINICAL SIGNIFICANCE The clinical technique described in this article has the potential for being used routinely in treating noncarious cervical lesions, especially in cases without easy access and limited field control. Precise margin finishing and polishing is one of the greatest benefits of the class V direct-indirect approach, as the author has seen it work successfully in his practice over the past five years.

Direct-Indirect Class V Restorations: A Novel Approach for Treating Noncarious Cervical Lesions.

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.

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

Effect of brushing on surface roughness, fluoride release, and biofilm formation with different tooth-colored materials

The purpose of this study was to evaluate the effect of roughness parameters and hydrophobicity of restorative material used to restore non-carious cervical lesions on the biofilm formation. Four restorative materials were investigated: conventional glass ionomer cement (KF, Ketac Fill Plus, 3M ESPE), resin-modified glass ionomer cement (VT, Vitremer, 3M ESPE), nanofilled resin-modified glass ionomer cement (KN, Ketac Nano, 3M ESPE), and nanofilled resin composite (FZ, Filtek Z350 XT, 3M ESPE). Forty disk specimens were prepared from each material, dived in four groups. Five samples were used for topography parameters analysis using a 3D profilometry. The amplitude parameters (Sa and Sq), spatial parameter (Sds), and hybrid parameter (Ssc) were extracted in area using cut-off of 0.25 mm. Hydrophobicity was determined by the contact angle measurement of deionized water on the surface. The biofilm collected from a 24-year-old subject was grown on modified brain–heart infusion agar under aerobic conditions at 37 °C for 24 h. Each test disk was immersed in 200 µL of biofilm suspension (n = 10) and incubated for 24 h at 37 °C. Biofilm was evaluated after 24 h formation on each disk after stained with 1 % fluorescein using confocal laser-scanning microscopy. Data were analyzed using one-way ANOVA and Tukey test (α = 0.05), Pearson correlation was used to compare topography parameters with biofilm formation. Significant differences were found in related amplitude parameters (Sa and Sq, FZ = KN > VT > KF). KN presented the highest hydrophobicity. FZ and KN presented the lowest thickness and biovolume of biofilm when compared with VT and KF. All topography parameters were significantly correlated with biofilm formation. FZ and KN, material with nanoparticles presented better performance-related topography parameters and biofilm formation. Clinical relevance: The incorporation of nanotechnology into restorative materials promotes better surface topography with lower biofilm formation.

Juliana Silvério Flausino

Papers

Biofilm formation on different materials for tooth restoration: analysis of surface characteristics