Dental Lab Products - April 2009 - (Page 40)

benchMASTERY PIZZI ON FIXED NOW When esthetics in dentistry is the topic of discussion, veneers, pressable materials, and zirconia dominate the conversation and the advertising media. Seldom do we hear or see metal mentioned as an “esthetic” substructure. Manufacturers would have us believe that if one of the newer technology markets is not in play, then we are missing out on something. In reality, approximately 70% of all restorative work done today is still processed on a metal substructure. I would never deny that these “newer” materials have great value in the marketplace. After all, there truly has been an increase in the number of restorations fabricated onto zirconia and other all-ceramic frameworks. However, the true perspective is that the number of dental restorations fabricated overall has increased, and porcelain-fused-to-metal still holds the predominate percentage in the market. This includes single units, small and large frames, metal inlays and onlays, full cast/metal occlusal veneers, and let’s not forget implant single units, multi-unit frames, and combination cases where metal implant-supported prostheses are used next to natural abutments. Each restorative solution has its strengths and weaknesses. If we follow the basic principles of working with metal-based restorative processes, then esthetics can be a strength in our metalbased products. METAL HERE AND A metal’s purity and makeup makes a difference in the esthetic outcome. WORKING WITH METAL Peter Pizzi, CDT, MDT Fig. A A pressure pot is mandatory today for investing and duplication. Fig. B Sprue conﬁguration sets the foundation for investing and casting. Fig. C Prefabricated feeder sprues work well off a runner bar. Fig. D A thickening of the feeder sprue is necessary with a greater amount of bulk in the casting. Fig. E Use of accessory vents is helpful in the casting process with large frames. Fig. F The feeder sprue for implants would be approximately the same width and weight as the implant being cast. METAL SELECTION What alloy properties most inﬂuence your decision to use a particular metal? Is it the coefﬁciency to your ceramic material, or is it price? Does the strength or workability of the metal further deﬁne your choice? Or, does your dentist request a particular formulation? One factor rarely mentioned is metal purity (trace elements) and coloration (oxides). Without getting into the material science of alloys, we can at least take a look at the Fig. G An example of poor trace elements after several ﬁrings. Coloration of these formed oxides creates a challenge for maintaining proper value on the restoration. Fig. H Better trace elements create cleaner and brighter oxides. Fig. I This allows the technician to have more control over the value-based outcome. Fig. J Ideal preparation. Fig. K Ideal preparation is not always ideal for the space requirements for ceramics. Fig. L Proper frame support can be controlled with the use of a provisional index. 40 dentallabproducts April dlpmagazine.com http://www.dlpmagazine.com

Table of Contents Feed for the Digital Edition of Dental Lab Products - April 2009

Dental Lab Products - April 2009 Contents From the Editor Product Watch New Face of Veneers Veneer Venue Chairside Metal Here and Now Seamless Integration Pressing Versatility Pinless Duplication The Fine Art of Delegating City of Big Ideas Spring Forward Industry News Easy Does It Art of Articulation Classifieds The Perfect Storm

Dental Lab Products - April 2009

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