RESUMO
Prosthodontic treatment is being performed for morphology and functional restoration due to damage and loss of teeth. As the aesthetic demands of patients increase, interest in ceramic materials with shades and translucency similar to natural teeth has increased.Recently, the manufacturing and processing technology of ceramic materials has greatly improved, and the market for dental ceramic materials is growing rapidly. The purpose of this literature review and evaluation is to provide information on the classification and properties of dental ceramic materials with excellent aesthetics and fracture resistance. In this article, it is classified as follows: I) Dental porcelain; II) Sinterable all-ceramic; III) Glass-ceramic for casting; IV) Glass-infiltrated alumina ceramic; V) Glass-ceramic ingots for heat-pressing technique; Vl) Blocks for CAD/CAM; Vll) Ceramic for CAD/3D printing. Dental ceramic materials and their restoration manufacturing methods have evolved significantly over the past decade. As a result, the manufacturing method of restorations has progressed from the layered firing technique of powdered materials or heat-pressing technique to the cutting and processing of single and multi-layer blocks using CAD/CAM technology, leading to the introduction of CAD/3D printing technology. In this manuscript, we will review the types of ceramic materials used in the fabrication of dental restorations and their advantages and disadvantages.
RESUMO
Titanium mesh is commonly employed to reinforce missing alveolar ridges and promote bone regeneration around implants. However, the bioinertness of titanium mesh must be improved. This study evaluated the effect of improving bioactivity and bone regeneration by loading a calcium phosphate coating layer and ibandronate onto a titanium mesh with a nanotube-structured TiO2 layer. The surface treatment of titanium mesh was divided into four groups: (1) No treatment; (2) Formation of nanotube TiO2 layer; (3) Cyclic calcification pretreatment (calcium phosphate coating layer) after the formation of a nanotube TiO2 layer; (4) Calcium phosphate coating and ibandronate loading after the formation of a nanotube TiO2 layer. The release amount of ibandronate was analyzed using a UV spectrophotometer, and bioactivity was assessed through XRD, EDS, and HR FE-SEM to observe changes in the surface layer after immersion in simulated body fluid (SBF). Hydroxyapatite was uniformly distributed on the surface of the (4) group immersed in SBF, and calcium and phosphorus content also increased over time. This result supported that bioactivity was improved. The continuous release of ibandronate over 10 days may contribute to realizing a mechanism that improves osseointegration between bone and titanium mesh. These results showed that bioactivity was improved as calcium phosphate precipitated on the surface of the nanostructured titanium mesh. Additionally, it is believed that combined ibandronate can effectively increase the stability of titanium mesh and promote bone regeneration.
RESUMO
The purpose of this study was to observe the surface morphology and roughness of micro-hybrid and nano-filled resin composites and compare wear resistance by conducting a toothbrushing wear test with toothpastes with different abrasive ingredients. Two types of resin composites containing micro-hybrid fillers (Z100 Restorative, Filtek Z250) and one type of resin composite containing nanofillers (Filtek Z350 XT) were used. For the toothbrushing wear test, 90 resin composite samples with a diameter of 10 mm and a thickness of 1 mm were prepared. A force of 2 N and 100,000 cycles of brushing were performed using a pin-on-disk wear tester. The toothpastes used in the test were classified into 4 groups according to the abrasive ingredients (hydroxyapatite, calcium carbonate, sodium bicarbonate, and zeolite-M). After the toothbrushing wear test, the surface morphology of the samples was observed using an optical microscope and a scanning electron microscope (SEM), and the surface roughness was measured using atomic force microscopy (AFM). Relatively large filler particles (micro size) protruded from the surface of the micro-hybrid resin composite groups, and small crater-shaped defects were observed. The surface roughness values of the groups that performed the wear test with toothpaste containing zeolite-M were significantly higher than the other groups (P<0.05). The surface roughness value was significantly (P<0.05) highest in the group where the nanofilled resin composite was wear-tested with toothpaste containing zeolite-M. However, regardless of the type of toothpaste, the surface roughness showed low values of less than 0.1 μm. The surface appeared uniform and smooth compared to the surface of micro-hybrid resin composites. Finally, the nano-filled resin composite showed relatively higher wear resistance than the micro-hybrid resin composite. This means that wear resistance during brushing may indicate the durability of the material in the clinic.
RESUMO
In order to investigate the occurrence of norovirus in rivers and beaches, a total of 81 samples were tested at seven sites of Oncheon stream, Suyeong river and Gwanganri beach in Busan from January to November, 2017. To improve the detection of norovirus from sea water, we applied the inorganic cation-coated filter method which showed 48.8% ± 12.2% (n=3) and 27.4% ± 6.0% (n=3) recovery yields from river water and sea water inoculated with Norovirus, respectively. Norovirus was detected in a total of four samples (4.9%), which all were GII genotype. Norovirus GII was detected in three samples at two waste water treatment plants (WWTP) outlet and one sample at about 500 meter downstream from WWTP in both the winter and spring seasons. We also monitored fecal indicator organisms, Escherichia coli (E. coli), Enterococcus and coliphages [somatic coliphages (SC), male-specific coliphages (MSC)] to analyze the potential transmission of enteritis causative agent in dry and wet days. Bacterial influences were found at the site of the WWTP effluents in the dry days and spread further to the costal beach in the wet days. But no viral influences were found in the river downstream in both dry and wet days.