Metal-free restorations continue to grow as a segment in dentistry. Dental laboratories continue to report that metal-free restorations have shown dramatic growth during the last five years. Five years ago, metal-free restorations were 20 percent of the overall restorations in the lab. Today, they represent 30 percent of the restorations fabricated in the laboratory.
Metal-free restorative options include composites, pressed ceramics, and cementable all-ceramic products. Each of these metal-free options has a place in current esthetic restorative dentistry. I will share what I think are the proper indications for each of these materials. We certainly have seen failures in the lab when dentists attempt to push these materials beyond their indications. There are still several clinical situations that call for the use of PFM restorations, but that list of situations is shrinking.
It is easy to profit from metal-free restorations because, by definition, they are appearance-related and typically esthetic in nature. Since they often are used to improve a patient’s smile, many patients are more motivated to have this type of treatment done as compared to ordinary restorative treatment. Furthermore, for restorations like porcelain veneers, there is no insurance benefit paid. This allows practitioners to set fees at any level they feel is fair. For example, I think that preparing and bonding veneers is more difficult than preparing and cementing crowns. Therefore, I believe that veneers should have a higher fee than typical crowns. Many dentists I meet do charge 10 to 25 percent more per unit for their veneers. Again, since insurance does not cover these restorations, you are free to set fees wherever you would like.
Pressed ceramics, such as IPS Empress, were the first metal-free restoration to make a large impact on dentistry. The increase in the popularity of porcelain veneers through the years can be tied directly to the development of pressed ceramics. I still think there is no restoration that is more esthetic than an Empress veneer. When done by a skilled technician, these restorations can rival the beauty of a natural tooth. I still use a lot of pressed ceramics, but only for prep and no-prep veneers. Now that we have stronger cementable all-ceramics for use on bicuspid and molar crowns, I confine my pressed ceramic use to veneers.
No-prep veneers are an amazing way to profit from metal-free dentistry. I was very skeptical of this concept initially, and did my first few cases with much trepidation. There is a clear set of advantages and disadvantages associated with no-prep veneers. The advantages include:
√ An esthetic treatment option for dental-phobic patients
√ The ability to correct smiles in a conservative fashion
√ Postoperative sensitivity should be nonexistent
√ No need for patients to spend two weeks wearing temporaries
There are also some disadvantages associated with no-prep veneers. These include:
⇒ They can be bulky if not made thin enough
⇒ They can allow the underlying tooth shade to show through, and thus influence the final shade
⇒ Since there is no margin prepared, the gingival margin is always bulky to a certain degree
⇒ If the gingival margin of the veneers is not kept clean by the patient, it can have adverse effects on the gingiva
However, no-prep veneers can work very well in “additive” type esthetic cases. These would be cases in which multiple diastemata are present, the teeth are shorter than they used to be due to trauma or wear, there has been a loss of facial enamel volume, or in which the only goal is to achieve “permanent bleaching.” I believe no-prep veneers are an area in which we need to have effective, written, informed consent with the patient about the different veneer options available. The sound of “no prep, no shots, no temps” is definitely music to many patients’ ears. But you still need to talk with them about the disadvantages of the no-prep technique.
As with traditional veneers, be careful during a no-prep try-in not to push the patient toward accepting veneers about which he or she is uncertain. In most veneer cases, it always seems like you are “married” to the patients, and you want to make sure that they love their veneers before they are bonded in place. Regardless of some of the advertisements seen in dental journals, I do not look at no-prep veneers as being reversible at all. I have removed no-prep veneers without any damage to the teeth before using my Waterlase YSGG laser from Biolase, but haven’t done it enough to recommend this technique as foolproof. I don’t believe you can remove no-prep veneers that have been bonded to enamel with a high-speed handpiece without doing some damage to the teeth. The bottom line is that I only consider veneers reversible while they are still filled with try-in paste.
Cementable all-ceramics have made great strides in the last decade, too. These systems represent a blending of all-ceramic esthetics with PFM cementability. These types of restorations are able to be cemented because of a high-strength coping on which the porcelain is stacked or pressed. Since they are stronger than the pressed ceramics, these restorations are particularly well-suited for posterior teeth and small bridges in areas in which esthetics are a concern.
The most popular cementable all-ceramic in our laboratory is Wol-Ceram. This is the only all-ceramic system that allows dentists to prepare a shoulder, chamfer, or feather-edge margin. Many dentists have complained about the extra preparation required for most all-ceramic restorations, thinking that a standard PFM preparation should be adequate reduction. Because Wol-Ceram uses an electro-deposition dipping technique, it can handle any margin design a dentist prepares - even if there is a shoulder, chamfer, or feather-edge margin on the same tooth.
Wol-Ceram restorations are built on high-density In-Ceram alumina material from Vita. In-Ceram crowns have been proven in clinical tests for more than 12 years, and literally millions of crowns have been cemented worldwide. On more than one occasion, I have heard CRA founder, Dr. Gordon Christensen, comment that In-Ceram is the best kept secret in dentistry. Dentists tend to be somewhat reluctant to try a new material that does not have a lot of clinical studies to support it. But In-Ceram is one of the most researched metal-free restorative systems available today. The results of a six-year clinical trial were recently published with a total of 546 metal-free In-Ceram crowns (177 anterior, 369 posterior) being cemented with RelyX luting cement. The success rate for the anterior crowns was 98.9 percent; the success rate for posterior crowns was 99.2 percent.
Watching the Wol-Ceram machine dip the master die into the alumina material is reminiscent of watching a master die being dipped into wax to fabricate a traditional cast gold restoration. This dipping procedure eliminates many of the preparation restrictions that are associated with CAD/CAM systems that utilize a scanner.
For me, a big part of all-ceramic cases, especially veneers, is a diagnostic waxup. This allows me to see what the proposed contours of the final restorations will look like. I also have the laboratory take an impression of the prepared model before the wax is added to it. This way, I am able to see how much preparation is needed to achieve the contours of the diagnostic waxup. Many times, I will have the lab do a suck-down over the prepared model that I can try on to the prepped teeth. Anywhere that the preps are in heavy contact with the suck-down shows where I need to prepare the tooth more in order to achieve the results that are shown on the waxup.
The waxup plays an especially important role when doing prepped veneers. We use the waxup to fabricate our temporaries quickly, typically taking less than 10 minutes. The technique for doing this is:
∧ Mix the base and catalyst from any putty that you use for your impression technique. Be sure to mix it well enough that there are no streaks visible in the putty material. Also, be sure to wash your hands prior to doing this to make sure there is no powder from your gloves on your hands.
∧ Take the putty material and push it onto the diagnostic waxup, making sure that the putty covers the entire arch - not just the teeth you are going to prepare. Let it set for the normal amount of time, and then remove it from the waxup. Anywhere the putty extends into the vestibule should be removed with a sharp Bard-Parker knife.
∧ Using whatever light body or extra-light body material that you typically use for your impressions, fill the putty matrix with this material. Reseat the putty matrix onto the waxup and let the light body material cure completely. This will take longer than usual since the warm temperature of the mouth does not accelerate the set time when you are impressing the waxup.
∧When you are satisfied with your preparations and have taken your final impression, fill the putty wash matrix with the bisacryl material of your choice. I often use the bleach shade of Luxatemp, especially if the patient is considering high-value veneers. This gives the patient the opportunity to see what high-value veneers would look like in his or her mouth. I also use the bleach shade material on darker teeth in order to help block out the stump shade.
∧Once the bisacryl has been placed in the putty wash matrix, seat it onto the teeth and leave it on for longer than you typically would. The temporaries are not going to be removed because we want them to lock onto the teeth. Don’t try to remove them, or you will break the seal you have achieved. It’s not a perfect seal but it is better than the one you will get if you try to remove the temporaries.
∧ You will be amazed when you remove the putty wash matrix because the temporaries are practically flawless! This makes the procedure much more profitable by not having to spend an hour fabricating the temporaries. At this point, the only work you may have to do is trim the gingival margins. Before taking the putty wash matrix, I define the gingival margins on the waxup with a No. 1/2 Hollenbeck instrument. This helps to ensure that, when you remove the matrix from the teeth, you will have very little gingival trimming to do.
∧ To remove the temporaries at the seat appointment, I use a 57 bur to cut a slot in the facial of each of the temporaries. I then use a crown remover to break the temporaries off the teeth. They will usually come off two at a time. If there is any “black scuzz” on the teeth due to leakage, this can be removed simply with a cotton pellet saturated in hydrogen peroxide. The black stains will disappear in seconds. This is the same mechanism that whitens teeth in a bleaching system.
∧ Make sure you save the putty wash matrix in case the patient is not happy when the veneers are tried in. Simply fill the putty wash matrix with bisacryl again, and you will have new temporaries in less than 10 minutes.
One of the most important uses of the diagnostic waxup is to help the patient decide whether he or she wants to proceed with the veneers. For this reason, I have all my diagnostic waxups done with white wax on a white stone model. White wax on a yellow stone model does not look as good to the patient because the yellow stone is distracting. Even worse is yellow or gray wax on a yellow stone model.
One of the interesting things you can do with the waxup is to fabricate the putty wash matrix at the consultation appointment. You can fill the putty wash matrix with bisacryl material and seat it onto the unprepared teeth. While this won’t give you an exact duplication of the waxup, since the teeth are not prepared, it does give the patient a general idea of what the veneers will look like. Many times, patients are somewhat impressed with how the preview veneers look in their mouth. My experience has been that, when you remove the preview veneers, patients are shocked to see what their original teeth look like. Many of my patients have decided on the veneers based on these preview veneers.
By using the techniques presented in this article, you will see an increase in the number of all-ceramic restorations you perform. By creating a demand for these services within your practice, you will find that profiting from all-ceramic restorations is one of the most rewarding ways to grow your practice.
Dr. Michael DiTollais the Director of Clinical Research and Education at Glidewell Laboratories in Newport Beach, Calif. He lectures on both restorative and cosmetic dentistry, and teaches hands-on courses on digital photography and digital image-editing for the entire team. Dr. DiTolla has several clinical programs available on DVD through Glidewell. For more information on this article, or for more information on receiving a free copy of one of Dr. DiTolla’s clinical DVDs, e-mail him at email@example.com, or call (888) 535-1289.