A woman (38 years) with tetracycline-stained maxillary anterior teeth came to dental office to improve her appearance. The porcelain veneers and zircon-porcelain crowns were selected as the best treatment option to mask the stained teeth. Medial line, occlusal line, level of gingival margin and frontal plane alignment of maxillary anterior teeth was analysed. Direct composite laminates were pla...

The aim of this study was to characterize a conventional and a pressed porcelain for zirconia core as to biaxial flexural strength (BFS), apparent fracture toughness (FT) and microstructure composition, and to investigate the effect of glaze cooling rate on the BFS of the zirconia/porcelain bilayers. Monolayers of conventional porcelain Vita VM9 and pressed porcelain Vita PM9 (n=15) (12 mm diam...

STATEMENT OF PROBLEM The bond strength of dental porcelain to titanium is inadequate as a clinical alternative to conventional alloys for metal ceramic restorations. PURPOSE The purpose of this in vitro study was to evaluate the effects of coating titanium surface with a micro-arc oxidation (MAO) technique and hydroxyapatite (HA) on the bond strength of porcelain to titanium surfaces. MATER...

STATEMENT OF PROBLEM In some clinical situations, the length of either a prepared tooth or an implant abutment is shorter than ideal, and the occlusal clearance to be restored by a porcelain crown is large. Incisal thickness of the coping and the veneering porcelain should be considered to prevent mechanical failure of the crown. PURPOSE The purpose of this study was to investigate the influe...

The aim of this study was to evaluate different curing times of a light-emitting diode (LED) unit on shear bond strength (SBS) of ceramic brackets bonded to feldspathic porcelain. Ceramic brackets were bonded with a light-cured adhesive to 96 feldspathic porcelain facets. Air-borne particle abrasion was performed using 25 mum aluminium trioxide (Al(2)O(3)) with an air abrasion device from a dis...

The metals for porcelain fusing used in this study were gold alloys and nickel-chromium alloys. Chromatic characteristics were compared between samples of 0.1, 0.2 and 0.3 mm thickness. The dentin porcelain was fused on the opaque surface. Chromatic analyses were then carried out at each stage of 0.1 mm-incremental reductions of the dentin thickness starting from 0.5 mm. In conclusion, the meta...

PURPOSE The aim of the present study was to assess the influence of pre-treatments of zirconia by sandblasting and/or heat treatment on the flexural strength of zirconia and debonding/crack-initiation strength of porcelain-veneered zirconia ceramic. MATERIALS AND METHODS Zirconia ceramic specimens were divided into four groups according to treatment (grinding as controls, sandblasting, heat t...

The vulnerability of the UHV porcelain arrester is very high under strong earthquake. To rise seismic reliability of the UHV porcelain arrester, a new type lead damper, which is a new patent product, is installed at the bottom of the equipment. To investigate the damping effect of the dampers, the experimental research and finite element analysis on seismic behavior of the UHV porcelain arreste...

Extensive restorations of single anterior teeth are accomplished by using porcelain jacket crowns or porcelain enamel or plastic veneer restorations supported by an alloy restoration that is luted to the tooth. The porcelain jacket crown has the advantage that less tooth tissue must be removed, but the material is brittle and lacks impact strength. Studies by McLean",2 have shown that these res...

generally, the failure rate and the repair time of system components are constant parameters in reliability assessment of electric distribution systems. a failure of component is resulted from failing in the operation or overloading. in addition, there exist cases where, the repair times of components are small and tolerable from customer point of view. thus, tolerable repair times may be overl...