Effect of TiO2 and CaO Addition on the Crystallization and Flexural Strength of Novel Leucite Glass-Ceramics.

The aim of this study was to investigate the effects of TiO2/CaO addition on the crystallization and flexural strength of leucite glass-ceramics (GC). Synthesis of translucent and high strength GCs is important for the development of aesthetic and durable dental restorations. To achieve this, experimental aluminosilicate glasses (1-3 mol% TiO2 and CaO (B1, B2, B3)) were melted in a furnace to produce glasses. Glasses were ball milled, screened and heat treated via crystallization heat treatments, and characterized using XRD, differential scanning calorimetry, dilatometry, SEM and biaxial flexural strength (BFS). Increasing nucleation hold time (1-3 h) led to a reduction in crystallite number for B2 and B3 GC, and significant differences in leucite crystal size at differing nucleation holds within and across test groups (p < 0.05). A high area fraction of leucite crystals (55.1-60.8%) was found in the GC, with no matrix microcracking. Changes in the crystal morphology were found with higher TiO2/CaO addition. Mean BFS of the GC were 211.2-234.8 MPa, with significantly higher Weibull modulus (m = 18.9) for B3 GC. Novel glass compositions enriched with TiO2/CaO led to crystallization of leucite GC of high aspect ratio, with high BFS and reliability. The study's findings suggest a potential high performance translucent leucite GC for use in the construction of dental restorations.

Synthesis of Novel Antimicrobial CHX-CaCl2 Coatings on Maxillofacial Fixatures for Infection Prevention.

Maxillofacial surgery placement of fixatures (Leonard Buttons, LB) at close proximity to surgical incisions provides a potential reservoir as a secondary local factor to advanced periodontal disease, with bacterial formation around failed fixatures implicating plaque. To address infection rates, we aimed to surface coat LB and Titanium (Ti) discs using a novel form of chlorhexidine (CHX), CHX-CaCl2 and 0.2% CHX digluconate mouthwash as a comparison. CHX-CaCl2 coated, double-coated and mouthwash coated LB and Ti discs were transferred to 1 mL artificial saliva (AS) at specified time points, and UV-Visible spectroscopy (254 nm) was used to measure CHX release. The zone of inhibition (ZOI) was measured using collected aliquots against bacterial strains. Specimens were characterized using Energy Dispersive X-ray Spectroscopy (EDS), X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). SEM displayed copious dendritic crystals on LB/ Ti disc surfaces. Drug release from double-coated CHX-CaCl2 was 14 days (Ti discs) and 6 days (LB) above MIC, compared to the comparison group (20 min). The ZOI for the CHX-CaCl2 coated groups was significantly different within groups (p < 0.05). CHX-CaCl2 surface crystallization is a new drug technology for controlled and sustained CHX release; its antibacterial effectiveness makes this drug an ideal adjunct following clinical and surgical procedures to maintain oral hygiene and prevent surgical site infections.