Method of fabricating high light transmission zirconia blanks for milling into natural appearance dental appliances

摘要

A process for fabricating pre-sintered zirconia blanks that are then computer machined and sintered to form dental appliances having highly advantageous features. The principal steps of a preferred embodiment of that process comprise a) preparing a ceramic slurry of binderless zirconia powder; b) subjecting the slurry to attrition milling down to about a 5-29 nm crystallite size; c) preparing a vacuum assisted and pressure assisted slip casting mold and pouring the milled slurry into the slip-casting mold; d) after casting, excess slurry is poured from the mold and a consolidated zirconia blank is removed; e) drying the blank and pre-sintering it to form solid blanks ready for CAD/CAM machining and sintering to net shape. The attrition is run with ball bearings that are of the sample material to prevent contamination. It also is run, up to 24 hours, to break down the crystallites to overcome the high density of zirconia.

主权项

1. A process for fabricating dental appliances of translucent zirconia; the process comprising the steps of:
a) preparing a ceramic slurry comprising mixing binderless zirconia powder, water and a dispersant; b) attrition milling the ceramic slurry to a crystallite size in the range of about 5 nm to about 29 nm; c) slip casting the milled ceramic slurry in a vacuum-assisted mold; d) removing water from the milled ceramic slurry and consolidating the zirconia powder to form zirconia blanks by subjecting one end of the vacuum-assisted mold to an evacuating pressure in a range of −5 to −40 psi and subjecting another end of the vacuum-assisted mold to a positive pressure in a range of 1 to 30 psi; e) removing zirconia blanks formed in said slip casting step; f) allowing the zirconia blanks to dry; g) pre-sintering the dried zirconia blanks to form dried, pre-sintered zirconia blanks; h) shaping the dried, pre-sintered zirconia blanks into appliance-shaped blanks; and i) sintering the appliance-shaped blanks to net shape and size.