HOME OF DENTAL PRODUCTS REPORT • DENTAL LAB PRODUCTS • MODERN HYGIENIST
Products
Printer Friendly
Email Article

August 2008 | Dental Products Report
Chairside Confidential | Full-coverage restorations


Choices, Choices

There are many all-ceramic options available today, but it can be difficult to determine when an all-ceramic alternative is a better choice than traditional metal-ceramic.

By Dr. Terry Donovan, Director of Fixed Prosthodontics, The Scottsdale Center for Dentistry


Contemporary patients demand dental restorations that are esthetic and functional. Manufacturers have introduced numerous all-ceramic alternatives to metal-ceramic restorations, and all-ceramic restorations are aggressively marketed to both patients and dentists.


Many dentists are somewhat confused about what these restorations offer in terms of improved esthetics, indications and contraindications, and life-span—making it difficult to sort out and determine which is the best option for their patients.


Tried-and-true metal-ceramics

 

 

Fig. 1 Using all-porcelain labial margins can significantly improve the esthetic potential of metal-ceramic crowns.

 

 

Fig. 2 Providing a textured opaque layer refracts incoming light and provides a more esthetic result than a smooth opaque layer.

 

 

 

Figs. 3 and 4 No all-ceramic crown system has clinical evidence meeting Peter Scharer’s criteria for longevity on molar teeth at the time of writing.

 

 

PFM crowns continue to be the restorations of choice when patients require crowns or fixed partial prostheses for posterior teeth. For anterior teeth in patients who prefer longevity to high esthetics, PFM used with an all-porcelain labial margin is the best option.


Given proper tooth preparation, soft-tissue management, and laboratory support, metal-ceramic crowns with porcelain labial margins can provide acceptable esthetics with maximum longevity (Fig. 1).


Today’s metal-ceramic restorations are vastly superior to those placed in the 1970s and 1980s. During those years, optimum tooth preparations were determined and simplified techniques for fabrication of porcelain margins developed.1-4 Techniques for internal colorization using textured opaques overlayed with more-translucent body and incisal porcelains became well-known (Fig. 2). These factors, coupled with a better understanding of color and shade selection, have made it possible to provide a high level of esthetics with metal-ceramic restorations.

 

The all-ceramic option

The primary indications for all-ceramic restorations are improved esthetics, biocompatibility, and cost. While their physical properties and strength have been improved with contemporary systems, they haven’t demonstrated that they can provide the same longevity as properly fabricated metal-ceramic restorations (Figs. 3 and 4). They are best for patients who are more concerned about the restoration’s esthetics than its longevity. The esthetic potential of every all-ceramic crown is not equal, and it is determined by the relative opacity of core material coupled with the ability to build in the color of the restoration intrinsically. Metal-ceramic crowns and In-Ceram Zirconia crowns (Vident) are almost completely opaque and allow no light transmission.5 The most translucent materials are IPS Empress (Ivoclar Vivadent) and feldspathic porcelain jacket crowns. Zirconia-cored restorations are significantly less translucent than IPS Empress crowns, but are slightly more translucent than metal-ceramic restorations. Thus, esthetic crowns can be placed in an esthetic crown continuum (Fig. 5).


Setting standards

When restoring anterior teeth where esthetics is more important than longevity, use the most esthetic system with a documented evidence base.


The criteria Peter Scharer suggests as an adequate evidence base seem appropriate and include the necessity for published independent clinical trials of three to five years with survival rates of 95% or better.7 The system that best meets these criteria is the original IPS Empress system. For single-unit crowns on anterior teeth, with patients who have high esthetic expectations, this is the restorative material of choice. IPS Empress restorations should be etched and bonded in place using a dual-cure resin cement. A self-adhesive resin cement (Rely-X Unicem, 3M ESPE) avoids the issues related to bonding the restoration in place using dentin primers and bonding agents.


CONTINUED ON NEXT PAGE


1 of 3
BROWSE BY CATEGORY