Browsing by Author "Aghyarian, Shant"
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Item Corrosion Behavior of Zirconia in Acidulated Phosphate Fluoride(Faculdade De Odontologia De Bauru) Thomas, Anie; Sridhar, Sathyanarayanan; Aghyarian, Shant; Watkins-Curry, P.; Chan, J. Y.; Pozzi, A.; Rodrigues, Danielli C.; Thomas, Anie; Sridhar, Sathyanarayanan; Aghyarian, Shant; Rodrigues, Danielli C.Objective: The corrosion behavior of zirconia in acidulated phosphate fluoride (APF) representing acidic environments and fluoride treatments was studied. Material and Methods: Zirconia rods were immersed in 1.23% and 0.123% APF solutions and maintained at 37°C for determined periods of time. Surfaces of all specimens were imaged using digital microscopy and scanning electron microscopy (SEM). Sample mass and dimensions were measured for mass loss determination. Samples were characterized by powder X-ray diffraction (XRD) to detect changes in crystallinity. A biosensor based on electrochemical impedance spectroscopy (EIS) was used to detect ion dissolution of material into the immersion media. Results: Digital microscopy revealed diminishing luster of the materials and SEM showed increased superficial corrosion of zirconia submerged in 1.23% APF. Although no structural change was found, the absorption of salts (sodium phosphate) onto the surface of the materials bathed in 0.123% APF was significant. EIS indicated a greater change of impedance for the immersion solutions with increasing bathing time. Conclusion: Immersion of zirconia in APF solutions showed deterioration limited to the surface, not extending to the bulk of the material. Inferences on zirconia performance in acidic oral environment can be elucidated from the study. ©2016, Journal of Applied Oral Science. All rights reserved.Item Evaluation of Mammalian and Bacterial Cell Activity on Titanium Surface Coated with Dicationic Imidazolium-Based Ionic Liquids(Royal Soc Chemistry, 2016-04-04) Gindri, Izabelle M.; Palmer, Kelli L.; Siddiqui, Danyal A.; Aghyarian, Shant; Frizzo, Clarissa P.; Martins, Marcos A. P.; Rodrigues, Danieli C.; 0000-0002-7343-9271 (Palmer, KL); Gindri, Izabelle M.; Palmer, Kelli L.; Siddiqui, Danyal A.; Aghyarian, Shant; Rodrigues, Danieli C.This work presents a new strategy to protect titanium surfaces against bacterial colonization and biofilm formation using dicationic imidazolium-based ionic liquid coatings. Ionic liquids (ILs) were designed as multi-functional coatings and their compatibility with human gingival fibroblasts (HGF-1) and preosteoblast (MC3T3-E1) cells was investigated. Results demonstrated that IL coatings were stable and present on titanium surfaces after 7 days of immersion and showed that using phenylalanine as the anionic moiety allowed for cell proliferation and differentiation on titanium surface while also providing strong antimicrobial and anti-biofilm activity against bacterial strains relevant to the oral environment (Streptococcus sp.). Strains such as Streptococcus mutans, S. sanguinis, S salivarius, S. gordonii and S. uberis are known to colonize the surface of dental implants in the early stages after implantation (early colonizers), compromising the success of these devices. The "race for the surface" between cells and bacteria was established by correlating results obtained from cell proliferation (epithelial and osteoblast) and differentiation (osteoblast) studies with that of antimicrobial activity against early bacterial colonizers.