Technological advances in all-ceramic

Italked recently with Keevin Shigenaka, manager of the all-ceramic department at Glidewell Laboratories.

I talked recently with Keevin Shigenaka, manager of the all-ceramic department at Glidewell Laboratories. Shigenaka has more than 30 years of experience in the dental lab business, and has a wealth of knowledge about the evolution and current state of all-ceramic technology. His lectures on all-ceramic restorations are almost always sold out. By itself, Shigenaka’s department is larger than most laboratories, so he has the advantage of being able to see a large cross-section of dentistry. Following are excerpts from our conversation.

D: Reading dental journals, I see many ads on no-prep veneers from various labs. I see the appeal for patients, but I sometimes worry about contours and margins. You have been doing no-prep for almost a year. What has the response been from dentists?

S: The response has been very favorable, overwhelmingly positive. I had the same reservations in regards to contours and margins. Previously, we always held a strict line as far as requiring adequate prep for our veneers. A combination of seeing others’ success plus the startling increase in popularity was a driving force in Glidewell Laboratories’ involvement. These items were the driving force in developing ThinPress ceramic material, allowing us to produce a veneer down to 0.3 mm when needed.

D: Are you at a point now where you are doing more no-prep veneers than traditional ones?

S: No. While no-prep and minimal-prep veneers are growing rapidly in popularity, the majority of veneers are still done by traditional reduction. About 25 percent are no-prep or minimal-prep. Minimal-prep is more common; most dentists do at least some preparation.

D: What do dentists who are using no-prep veneers say is the main reason they prefer this approach?

S: Dentists like the technique because there is no prepping or temporization and almost no chance of post-op sensitivity. Dentists also tell us it’s one of the most profitable procedures they perform since there is no preparation, temporization, or impression. The first appointment in a no-prep case takes about 10 minutes. The second appointment usually goes smoothly because no dentin bonding is involved, thus there is no need for a rubber dam. Often doctors take a diagnostic study model and send it to us so we can evaluate whether the patient would be a good no-prep candidate. If necessary, we will mark any areas on the model where the doctor needs to do minor reduction with a sandpaper disc or bur.

D: I get many questions at my lectures about what cementable all-ceramic restorations dentists should be using. What are your thoughts on the newer cementable all-ceramic materials? Do you have a favorite?

S: We have an array of options today. We have an array of options today, alumina and zirconia substructures allow for just about any indication to be covered. We have learned that Wol-Ceram is our most popular all-ceramic restoration. The ability to utilize this product on any type of preparation is a great benefit to the dentist, and certainly expands the definition of all-ceramic. Dentists also love the conventional cementation with materials such as 3M ESPE’s RelyX Luting Cement Plus or Fuji Plus. Much focus is now being paid to Zirconia. Lava seems promising from our early experiences. Dentsply’s Cercon has a new version of software set for release that incorporates the CAD process into its milling.

D: Regarding all-ceramic preparations that you see when you pour dentists’ master impressions, what are the main mistakes you see consistently?

S: Newer materials we use are more forgiving in regard to marginal prep design. However, we find sharp internal line angles and inadequate reduction continuing to be the primary issues.

D: How helpful is it for technicians when a dentist e-mails a color photo of a tooth for restoration?

S: It’s a great advantage to the point of being almost better than seeing it chairside since you have the image of the whole production process. More and more dentists send pictures to us. All a doctor has to do is e-mail us a jpeg with his or her name, patient name, and tooth number to acphoto@glidewell-lab.com, and it will be included with the case. Technicians seem to spend more time with cases that include photos because they feel they are able to get a more proper match with the adjacent teeth, and they know the doctor cared enough to take a photo of the tooth. Doctors also love to critique work in progress, either by seeing a diagnostic wax-up or bisque-stage photo. If all dentists used photography, the level of quality in all-ceramics would increase immediately.

Dr. Michael DiTolla is the Director of Clinical Research and Education at Glidewell Laboratories in Newport Beach, Calif. He lectures nationwide on both restorative and cosmetic dentistry. He also 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 mcditolla@mac.com, or call (888) 535-1289.

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