Quantum mechanical analysis of yttrium-stabilized zirconia and alumina: implications for mechanical performance of esthetic crowns.

BACKGROUND: Yttrium-stabilized zirconia (YSZ) and alumina are the most commonly used dental esthetic crown materials. This study aimed to provide detailed information on the comparison between yttrium-stabilized zirconia (YSZ) and alumina, the two materials most often used for esthetic crowns in dentistry. METHODOLOGY: The ground-state energy of the materials was calculated using the Cambridge Serial Total Energy Package (CASTEP) code, which employs a first-principles method based on density functional theory (DFT). The electronic exchange-correlation energy was evaluated using the generalized gradient approximation (GGA) within the Perdew (Burke) Ernzerhof scheme. RESULTS: Optimization of the geometries and investigation of the optical properties, dynamic stability, band structures, refractive indices, and mechanical properties of these materials contribute to a holistic understanding of these materials. Geometric optimization of YSZ provides important insights into its dynamic stability based on observations of its crystal structure and polyhedral geometry, which show stable configurations. Alumina exhibits a distinctive charge, kinetic, and potential (CKP) geometry, which contributes to its interesting structural framework and molecular-level stability. The optical properties of alumina were evaluated using pseudo-atomic computations, demonstrating its responsiveness to external stimuli. The refractive indices, reflectance, and dielectric functions indicate that the transmission of light by alumina depends on numerous factors that are essential for the optical performance of alumina as a material for esthetic crowns. The band structures of both the materials were explored, and the band gap of alumina was determined to be 5.853 eV. In addition, the band structure describes electronic transitions that influence the conductivity and optical properties of a material. The stability of alumina can be deduced from its bandgap, an essential property that determines its use as a dental material. Refractive indices are vital optical properties of esthetic crown materials. Therefore, the ability to understand their refractive-index graphs explains their transparency and color distortion through how the material responds to light..The regulated absorption characteristics exhibited by YSZ render it a highly attractive option for the development of esthetic crowns, as it guarantees minimal color distortion. CONCLUSION: The acceptability of materials for esthetic crowns is strongly determined by mechanical properties such as elastic stiffness constants, Young's modulus, and shear modulus. YSZ is a highly durable material for dental applications, owing to its superior mechanical strength.

The effect of photobiomodulation therapy in common maxillofacial injuries: Current status.

The use of photobiomodulation therapy (PBMT) may be used for treating trauma to the maxillofacial region. The effects of PBMT on maxillofacial injuries were discussed in this review article. The electronic databases Pubmed, Scopus, and Web of Science were thoroughly searched. This review included in vitro, in vivo, and clinical studies describing how PBMT can be used in maxillofacial tissue engineering and regenerative medicine. Some studies suggest that PBMT may offer a promising therapy for traumatic maxillofacial injuries because it can stimulate the differentiation and proliferation of various cells, including dental pulp cells and mesenchymal stem cells, enhancing bone regeneration and osseointegration. PBMT reduces pain and swelling after oral surgery and tooth extraction in human and animal models of maxillofacial injuries. Patients with temporomandibular disorders also benefit from PBMT in terms of reduced inflammation and symptoms. PBMT still has some limitations, such as the need for standardizing parameters. PBMT must also be evaluated further in randomized controlled trials in various maxillofacial injuries. As a result, PBMT offers a safe and noninvasive treatment option for patients suffering from traumatic maxillofacial injuries. PBMT still requires further research to establish its efficacy in clinical practice and determine the optimal parameters.

Anti-fungal efficacy of Miswak Extract (Salvadora Persica) and commercial cleaner against Candida albicans on heat cured polymethylmethacrylate denture base.

AIM: The aim of the study was to compare the antifungal efficacy between commercial cleaner (Corega) and Miswak extract (Salvadora persica) against Candida albicans on heat cured Polymethyl methacrylate (PMMA) acrylic denture base resin. MATERIALS AND METHODS: Forty-eight samples of heat cured PMMA acrylic denture base resin were fabircated in the study. The sterile acrylic resin specimens were immersed in standardized cell suspension of Candida albicans and incubated for 60 min at 370°C for cell adhesion and 2 h at 370°C for biofilm formation. After 24 h biofilm was evaluated by cell viability (CFUs) on SDA and cell counting of Candida albicans under light microscope at 400× magnification. The fungicidal effect of commercial cleaner and Miswak extract on Candida albicans biofilm was then evaluated by colony-forming units on SDA and cell counting under light microscope at 400× magnification. RESULTS: Screening test agar disk-diffusion assay showed mean inhibitory zone of 3 mm for commercial cleaner as compared to Miswak extract, which showed mean inhibitory zone of 2 and 1 mm for different concentrations. Broth microdilution method showed 31 mg/ml MIC and 62.5 mg/ml Minimal Fungicidal Concentration (MFC) values for commercial cleaner as compared to Miswak extract that showed 125 mg/ml MIC and 250 mg/ml MFC values against Candida albicans. A significant difference (p < 0.05) was observed between pre and post treatment of both commercial cleaner and Miswak extract, for CFUs and cell count for Candida albicans. CONCLUSION: Commercial denture cleaner (Corega) showed better antifungal (C albicans) activity than Miswak extract (Salvadora persica) on heat cured PMMA acrylic denture base resin.

Comparative evaluation of Sapindus Mukorossi extract with 17% EDTA on smear layer removal in various parts of the tooth root.

OBJECTIVES: This study aimed to compare the effectiveness of an experimental root canal irrigant and 17% Ethylene-di-amine tetra acetic acid for removal of the smear layer in the coronal, middle and apical portions of the root canal. MATERIALS AND METHODS: Ninety human single rooted maxillary and mandibular teeth were selected for this study. The teeth were randomly divided into two experimental groups and one control group as follows: Group A (Ethanolic extract of Sapindus Mukorossi), Group B (17% EDTA), and Group C (Distilled water). The root canals of all three groups were prepared with stainless steel K-files by means of the standard step-back technique and irrigated with 5.25% sodium hypo chloride. The teeth were decoronated, following the irrigation and divided longitudinally into two-halves and visualized using scanning electron microscope (SEM) for the amount of smear layer present utilizing the three-point score system. The observations were noted both before and after the treatment. Nonparametric tests were applied for the comparison and p-value ⩽ 0.05 was considered as statistically significant. RESULTS: It was evident from that smear layer was completely removed in coronal portion of 27 out of 30 teeth in-group A. For middle and apical areas of group A, 24 and 19 teeth showed complete smear layer removal. In-group B it was found that there were 24, 21, and 3 teeth at coronal, middle and apical, areas respectively where smear layer were completely absent. Intra group comparison showed a significant difference (p = 0.002) in smear layer removal was found for group A at coronal, middle and apical thirds. Similarly, a significant difference (p = 0.001) was also found for group B; however heavy smear layer was found among the three parts of the canal for group C. CONCLUSIONS: Ethanolic extract of Sapindus Mukorossi have higher effectiveness in removing the smear layer from the root canal in comparison to 17% EDTA.

Synthesis of Silver Nanoparticles from Extracts of Wild Ginger (Zingiber zerumbet) with Antibacterial Activity against Selective Multidrug Resistant Oral Bacteria.

Antibiotic resistance rate is rising worldwide. Silver nanoparticles (AgNPs) are potent for fighting antimicrobial resistance (AMR), independently or synergistically. The purpose of this study was to prepare AgNPs using wild ginger extracts and to evaluate the antibacterial efficacy of these AgNPs against multidrug-resistant (MDR) Staphylococcus aureus, Streptococcus mutans, and Enterococcus faecalis. AgNPs were synthesized using wild ginger extracts at room temperature through different parameters for optimization, i.e., pH and variable molar concentration. Synthesis of AgNPs was confirmed by UV/visible spectroscopy and further characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy analysis (EDXA), and Fourier-transform infrared spectroscopy (FTIR). Disc and agar well diffusion techniques were utilized to determine the in vitro antibacterial activity of plant extracts and AgNPs. The surface plasmon resonance peaks in absorption spectra for silver suspension showed the absorption maxima in the range of 400-420 nm. Functional biomolecules such as N-H, C-H, O-H, C-O, and C-O-C were present in Zingiber zerumbet (Z. zerumbet) (aqueous and organic extracts) responsible for the AgNP formation characterized by FTIR. The crystalline structure of ZZAE-AgCl-NPs and ZZEE-AgCl-NPs was displayed in the XRD analysis. SEM analysis revealed the surface morphology. The EDXA analysis also confirmed the element of silver. It was revealed that AgNPs were seemingly spherical in morphology. The biosynthesized AgNPs exhibited complete antibacterial activity against the tested MDR bacterial strains. This study indicates that AgNPs of wild ginger extracts exhibit potent antibacterial activity against MDR bacterial strains.