Crowns are often used to restore a tooth to beauty and full function when a substantial amount of tooth structure has been lost due to breakage, decay, or a large old filling that has failed. Dr. Fondriest prefers to use all-porcelain or all-ceramic versions over those made with metal. The all-ceramic version can be more aesthetic and will never develop an ugly black line at the gum line caused by the metal crown margin showing. Ceramic restorations can be made thinner thus requiring less tooth reduction. These restorations can be made to closely match the light transmitting properties of natural teeth and will not stain or change color. Ceramics are more biocompatible than most metals which may reduce the potential for gum recession and lead to a more long-term healthy result.
TYPES OF PORCELAIN CROWNS – HOW ARE THEY MADE?
E Max is the newest cosmetic porcelain. It is both strong and has true-to-nature shade behavior and excellent light transmission for highly esthetic solutions. This is Dr. Fondriest’s new preferred ceramic system for anterior teeth. EMax is both biocompatible and has the long term wear characteristics like that of enamel. It can be used for minimally prepared veneers or crowns to as thin as 0.2mm.
E Max is ideal for fabricating single-tooth restorations or complete smile makeovers. This ceramic two layer system (pressed coping and custom stacked superficial layer) produces beautiful restorations and is 2.5 to 3 times stronger than other glass-ceramic systems used today.
E Max Monolithic
When an all porcelain restoration chips or fractures, it is likely that the break occurred in the superficial veneering porcelain. It is the veneering porcelain that is the weak link in all of these systems. E Max Monolithic does not have a veneering porcelain. Unlike the other systems, the EMax HT (high translucency) coping material can be used without a veneering layer due to improved optical characteristics. This coping material can be used alone to create veneers or crowns suitable for grinders. This restorative option is one of the most popular ceramic choices for patients who are nightime bruxers or tooth grinders.
Empress crowns can be produced with excellent fit and the characteristics of natural teeth. Empress has two layers; a base coping made of medium-strength pressed ceramic, and a highly customizable superficial glass layer that can be hand stacked and fired on top of the supportive pressed base coping. With only modest strength, this restorative material should never be used in high occlusal risk situations.
Many cosmetic dentists feel that this is the most attractive porcelain. This custom stacked monolithic ceramic (one layer or no supportive base coping) is difficult to work with and requires the technician to have very high skills. Only high end dentists will use this ceramic system. These restorations are very technique sensitive to place and are more costly to produce in the laboratory.
Procera is a two layer system. They are made with an aluminum oxide base coping that is custom milled with CAD technology and a superficial stacked feldspathic layer that is used to make the restoration attractive and lifelike. Due to the opacity of the coping, the tooth needs to have a more aggressive preparation to allow enough veneer thickness to mask the bright white coping. These restorations can also be beautiful when crafted by a master ceramist.
Zirconium onlays, caps or crowns are similar in design to Procera with a two layer system. This porcelain option is used commonly for bridges and implant abutments. Zirconium itself has a limited capability of being bonded and should not be used for veneers. In addition, the high opacity and unnatural whiteness of the strong zirconium base coping can require more tooth reduction to give room to conceal it with a thicker veneering porcelain layer. There are many brands of this product and some have higher clinical success rates.
Should Zirconia crowns be used for front teeth?
Zircomium crown technology is still developing. The optical characteristics are improving quickly and newer options are coming to market with more translucency and esthetic attractiveness.
Do zirconium crowns and/or onlays break?
Yes, everything can break including zirconium and natural teeth. A zirconium base coping is extremely strong, in fact much stronger than natural tooth structure. Due to the lack of natural optical characteristics, the coping must be covered with weaker veneering porcelain for esthetic parity. When dentists have limited knowledge of occlusion or the patient grinds their teeth, it is common for any type of restoration to break. Zirconium is attractive to some dentists due to a false impression of superior strength. The veneering porcelain has the same low shear strength as for all of the other porcelain 2 layer systems and is the weak link rendering it no stronger than any of the other systems. The exception is when no veneering porcelain is used. Due to heavy marketing directly to dentists promising superior strength, many practitioners are choosing base coping only (monolithic) zirconium restorations. These restorations can be very abusive to the opposing dentition and exhibit low esthetic quality. The zirconium coping has the translucency and vitality of a toilet bowl; white opaque. Also they can be very difficult to remove without hurting the underlying tooth. No matter what you hear or read, all dental restorations have a finite life span and eventually need replacement. 100% Zirconium inlays and onlays are not recommended.
Cerec and Sirona
Cerec and Sirona technology is becoming more popular in average dental offices because it cuts out the lab technician. The brand names Cerec and Sirona are “in-the-dental-office” CAD milling machines. Monolithic ceramic blocks are milled into onlays, veneers or for full coverage. Monolithic means one color. No natural tooth is one color. These restorations can be created in one visit and are strong but they can only be customized by using surface stains. Surface staining creates opacity and metamerism and is not life like. Surface stains wear off over time.
CROWN MATERIAL SELECTION FACTORS:
Porcelain choices are made based on strength, esthetics, and the abrasiveness of the material against the opposing teeth. The skill level of the dentist will also influence what type of porcelain is used. There is no single porcelain choice that is clearly superior for all situations. For example, feldspathic and EMax HT (high translucency) are better choices to avoid black lines at the gumline. Many cosmetic dentists will have several types that they use for different situations. There are subtleties in working with all of these ceramic materials that need to be mastered by
the dentist and the ceramist to produce the most beautiful result.
What does a Porcelain Crown Cost?
Like all commodities, costs vary with the time, expertise, and materials used to create a porcelain crown. Depending on the quality level of the dental office and ceramist (who actually fabricates the crown and charges the dentist directly for his/her service), the price of a single porcelain crown could be anywhere from $900 to $3500. Do not assume that the dentist charging $3000 is making any more money per crown than the dentist charging $600. The quality levels of porcelain crowns vary tremendously. A better crown will look more natural, have a better bite, be stronger, last longer, fit better and will not fray or snap your floss. The gum tissue will be healthier and the tooth will be less likely to decay or leak. The old adage “you get what you pay for” very often (not always, so be careful) applies to porcelain crowns. When choosing a dentist to do your crowns, it is important to know that the complexity of a case goes up tremendously when multiple teeth need crowns at the same time. Do your homework and get several opinions; find a dentist that has the appropriate training and does these procedures all of the time and has before and after photos of cosmetic dentistry .
Dr Fondriest is a Nationally recognized and highly sought after cosmetic dentist serving clients from throughout the United States