The preparation must be designed to provide the correct support for the porcelain along its entire incisal edge unless an all ceramic crown with a strong core i e.
Molar metal ceramic crown preparation.
Only with sufficient thickness can the darker color of the metal substructure be masked and the veneer duplicate the appearance of a natural tooth.
Only with sufficient thickness can the darker color of the metal substructure be masked and the veneer duplicate the appearance of a natural tooth.
The extent of the veneer can vary.
However sometimes the metal underlying the crown s porcelain can show through as a dark line especially.
The metal should be 0 3 to 0 5 mm thick if it is a noble metal alloy while a metal coping made of the more rigid base metal alloys can be thinner to 0 2 mm.
Metal ceramic porcelain fused to metal 2 0 mm incisally 0 5 1 0 mm lingual aspect porcelain guidance requires greater clearance 1 5 mm labial shoulder or heavy chamfer 0 5 mm lingual chamfer 1 5 mm circumferentially for 360 degree ceramic margin.
Metal ceramic crown preparation 2.
The extent of the veneer can vary.
To be successful a metal ceramic crown preparation requires considerable tooth reduction wherever the metal substructure is to be veneered with dental porcelain.
Most widely used.
Because there is no metal to block light transmission they can resemble natural tooth structure better in terms of color and translucency than can any other restorative option.
Veneer porcelain mimics 3 extention varies natural teethnatural teeth 4.
Full contour crowns metal or zirconia 1 0 mm non functional cusps 1 5 mm.
To be successful a metal ceramic crown preparation requires more tooth reduction wherever the metal substructure is to be veneered with dental porcelain.
Ensuring the preparation has a 90 cavosurface angle helps to prevent unfavourable distribution of stresses and minimises the risk of the crown fracturing.
Complete coverage by metal.
Next to all ceramic crowns porcelain fused to metal crowns look most like normal teeth.
To be successful a metal ceramic crown preparation requires considerable tooth reduction wherever the metal substructure is to be veneered with dental porcelain.