Dental Tribune Middle East & Africa Edition

Trends & Applications DENTALTRIBUNE Middle East & Africa Edition We at Dentallabor Cera-Tech in Liestal/Switzerland, con- centrate to a large extent on CAD/CAM technology and spend a lot of time advocating the cause of allceramics. Nev- ertheless, metal ceramic, com- prises around 30% of our range of products and services, con- tinues to remain an indispensi- ble part of our programme. Gold accounts for 70% of this, and – trend increasing – non- precious metal alloys 30 %. The following article pres- ents a corresponding case exam- ple. Customer requirement and planning The patient‘s tooth 11 was fractured and tooth 21 showed severe cracks (fig. 1). The re- quirements of the dentist were clearly defined, and communi- cated by oral agreement and an order form: the crowns were to be implemented as a standard restorationinmetalceramic,and at the same time blend harmo- niouslywiththepatient‘soralsit- uation. For this reason, we decided to have the shade determination performed in the dental practice, and instead of using the casting technique,tofabricatethecrown coping by milling a CAD/CAM restoration from a non-precious metal alloy. For the veneer we chose VITA VMK Master, a new metal ceramic for veneering in the classical style, and which promises brilliant shade repro- duction. The implementation For shade determination we use – with growing enthusiasm – the VITA Linearguide 3D-Mas- ter, which is also finding increas- ing approval on the part of our dentist customers. We like the fact that it is based on the already known linear principle because itdoesnotrequireanyrethinking in terms of the concept. Also in the case described here, the den- tist used this for determining the toothshade.Inadditiontothis,he documented the situation prior to treatment and the results of shadedeterminationwithregard to lightness and chroma by means of digital photographs which he sent us by e-mail. Fur- ther discussion of the case took place by telephone. This proce- dure usually enables us to achieve a remarkably high de- gree of accuracy, even without the dental technician having come into contact with the pa- tient in person. The master model was scanned and used as a basis for the virtual framework design, and the latter was milled from a non-precious metal alloy. An im- portant prerequisite for digitisa- tionisthatthedentistmustbeac- curate in his preparation work, so that the preparation margin canbeeasilyreadbythescanner. Theriskofcavitiesandporosities which could endanger the ve- neer, and in the event of late cracks result in work covered by guarantee, is no longer given in CAD/CAM manufacture, since the non-precious metal blanks are industrially fabricated ac- cording to unified quality stan- dards. A further advantage of the milled non-precious metal cop- ings is their high degree of mar- ginal accuracy. The work re- quiredinthefittingofthecopings is reduced to a minimum – only the mounting pins have to be re- moved, and the margin finished in such a way that it tapers thinly. We used a silver and palla- dium-free alloy which has high strength values that enable it to withstand a high load capacity. This offers a high-quality, and, above all, a cost-effective alter- native to all-ceramic and gold content solutions. For the opaque application we use the SPRAY ON procedure (fig. 2), so that a thin and homo- geneous layer thickness is achieved,whichatthesametime has good covering power. The Metal ceramic – well-proven and fu- ture oriented 8 Fig. 1: Situation before treatment. Fig. 2: Opaque application in the VITA SPRAY-ON procedure. Fig. 3: Completing the build-up with enamel and effect porcelains. Fig. 4: End result directly after seating the restoration. Exclusive Distributor : Pharmapal Drug Store Tel +971 4 2675001, PO Box 37345 Dubai, United Arab Emirates www.pharmapaluae.com