Niyom Thamrongananskul

Comparison of the surface roughness of feldspathic porcelain polished with a novel alumina-zirconia paste or diamond paste

This study compared the surface roughness of feldspathic porcelain polished with newly developed alumina-zirconia pastes or diamond paste. Porcelain discs were prepared and polished with sandpaper using a polishing-machine. The surface roughness (Ra) of each sample was measured using a profilometer. The samples were randomly divided into 6 groups (n=10). The control group was polished with diamond paste (DP), and the five remaining groups were polished with the newly developed alumina-zirconia paste with the following ratios of glycerin:alumina:zirconia by weight: 1:0.5:0.5 (Z0.5), 1:0.5:0.75 (Z0.75), 1:0.5:1 (Z1), 1:0.5:1.5 (Z1.5), and 1:0.5:2 (Z2). The specimens were polished for 120 s. The Ra values were determined again and the surface morphology of the porcelain samples was analyzed using SEM. The Ra values decreased as the amount of zirconia in the polishing paste increased, except for the Z2 group. The surface roughness as observed by SEM showed a correlation with the Ra values.

Fluoride Recharge Ability of Resin-Based Pit and Fissure Sealant with Synthesized Mesoporous Silica Filler

The aim of this study was to examine the effects of active filler in resin-based pit and fissure sealant on fluoride release and recharge abilities. Mesoporous silica was synthesized from tetraethyl orthosilicate (TEOS) using sol-gel method. Resin-based sealant was incorporated with 5% w/w of filler (<45 μm): synthesized mesoporous silica (S), calcium carbonate (C), and fluoro-alumino silicate glass (F). Resin-based sealant without filler added was the control. Ten specimens of each group were separately stored in 3 mL of deionized water and the fluoride concentration, before and after fluoride recharge, were measured every 3 days (from day 3 to day 27). Fluoride release before recharge was only found in F (0.1024±0.0077 ppm) and then gradually decreased to baseline. After two recharges, the highest fluoride release was found in S (0.0804±0.0095 ppm after first recharge and 0.0601±0.0092 after second recharge), followed by F (0.0386±0.0024 ppm after first recharge and 0.0313±0.0027 ppm after second recharge), and then decreased to baseline. Fluoride recharge was not found in C and control. This result suggested that resin-based pit and fissure sealant containing synthesized mesoporous silica filler has fluoride recharge ability which might prevent secondary caries at material-enamel interface.

Synthesized mesoporous silica and calcium aluminate cement fillers increased the fluoride recharge and lactic acid neutralizing ability of a resin-based pit and fissure sealant

This study evaluated the effect of different types of filler in a resin-based pit and fissure sealant on fluoride release, recharge, and lactic acid neutralization. Resin-based sealant was incorporated with 5% w/w of the following fillers: calcium aluminate cement (CAC), synthesized mesoporous silica (SI), a CAC and SI mixture (CAC+SI), glass-ionomer powder (GIC), and acetic acid-treated GIC (GICA). Sealant without filler served as control. The samples were immersed in deionized water or a lactic acid solution and the concentration of fluoride in the water, before and after fluoride recharge, and the lactic acid pH change, respectively, were determined. The CAC+SI group demonstrated the highest fluoride release after being recharged with fluoride gel. The CAC+SI group also demonstrated increased lactic acid pH. These findings suggest that a resin-based sealant containing synthesized mesoporous silica and calcium aluminate cement may enhance remineralization due to fluoride release and higher pH.

Preparation and Characterization of Polymer Blends from Nang noi srisaket 1 Silk Fibroin, Gelatin and Chitosan Nanofiber Mats Using Formic Acid Solution

Silk fibroin, gelatin, and chitosan blended solution in formic acid with different composition ratios were electrospun. The fiber could be produced from SF:G : C blended solution at weight blending ratios (%wt: %wt: ml) of 10:20:0, 10:20:0.5, 10:20;1, 10:20:1.5, 10:20:2, and 20:10:1. When the chitosan content in blended solution increased, the average diameter decreased from 245 to 100 nm and fiber size distribution was narrow. The SF: G: C solution at ratio of 10:20:1 under high electric field and long spinning distance provided the continuous and uniform fibers. The formic acid as solvent did not affect to the electrospinnability and morphology of SF: G: C blended nanofiber. Tensile strength of SF: G: C (10:20:1) blended nanofiber was decreased with increasing of silk fibroin content, SF: G: C (20:10:1). The results indicated that SF: G: C electrospun nanofiber mats could be prepared and have a potential to be applied in membrane application.