Ask Dr. Christensen

Sept. 1, 2003
In this monthly feature, Dr. Gordon Christensen addresses the most frequently asked questions from Dental Economics readers.

by Gordon J. Christensen, DDS, MSD, PhD

In this monthly feature, Dr. Gordon Christensen addresses the most frequently asked questions from Dental Economics readers. If you would like to submit a question to Dr. Christensen, please send an email to [email protected].

Question ...
What type of crown should be used to restore one single central incisor that has a darkened root stump and a post and core? I have tried porcelain-fused-to-metal, but, due to the difficulty of matching the adjacent teeth, I have achieved only fair results. I have tried Empress, but the gray color of the root shows through the crown.

Answer from Dr. Christensen ...

You have identified a difficult clinical situation. Let's start with the patient's lips. If the patient does not show gingiva when smiling, the solution is easier than if a significant amount of gingiva shows. If the root is gray and the patient shows gingiva apical to the crown margin, it is almost impossible to achieve an excellent aesthetic result. The gray of the root shows through the bone and gingival tissue, causing the gingival tissues to have a gray color and lack of aesthetic acceptability. Some clinicians suggest bleaching the root internally, but I advise refraining because of reports of root resorption subsequent to bleaching root structure. In severe cases of gray roots and significant gingival display, the only way to produce an aesthetic result is to extract the tooth and place an implant and a crown, or extract the tooth, place some grafting material in the socket to preserve the ridge anatomy, and place a three-unit, fixed partial denture, replacing the missing tooth.

If the gingiva does not show when the patient smiles or the color of the gingival tissues is not objectionable, the challenge can be solved more simply. Obviously, an opaque internal surface is required on the crown to block the root's gray color. The translucent, pressed-ceramic crowns are not a good choice for this situation, because, as you stated, the gray root color shows through. A single, porcelain-fused-to-metal (PFM) crown is difficult to match to surrounding anterior teeth. Some dentists find the task to be nearly impossible. If several anterior crowns are required, PFM crowns are a good choice, since it is easier to match the color with multiple units. Only a few all-ceramic crowns have internal surfaces that are sufficiently opaque to block the color of the gray root. Some of the newer zirconia internal core all-ceramic crowns can be acceptable. If your laboratory technicians are competent with Cercon from Dentsply Ceramco or LAVA from 3M ESPE, these restorations may be good choices.

There is a material that has been around for more than 14 years and has been my long-time favorite for covering the gray color of single anterior roots, while allowing the placement of life-like, tooth-colored, fired ceramic over the opaque coping — In-ceram Alumina from Vident. A new, easier, faster version of the same concept is In-ceram Sprint from Vident. Sprint uses glass-infiltrated alumina ceramic that is built up by the technician in a manner faster than previously used "slip castings." These products are opaque internally and will successfully block the gray color of discolored roots. However, beautiful aesthetic results can be achieved with the fired veneering ceramic.

One of our newest videos shows the challenges that are peculiar when cementing all-ceramic crowns. This video will update your technique and educate your staff. For more information about C102A, "Cement — A Critical Choice," please call (800) 223-6569, fax (801) 226-8637, or visit our Web site at

Question ...
Should Class II resin-based composite restorations have a higher fee than amalgam, and if so, how much higher? I find that I am taking a significantly longer time to place a Class II composite restoration than a similar-sized Class II amalgam, but my third-party payment companies have the fees similar for the two procedures.

Answer from Dr. Christensen ...

When I started to place Class II resin-based composite restorations many years ago, they required an inordinate amount of time compared to amalgam. I attribute this phenomenon to the fact that the working properties of amalgam and composite are markedly different, and time is required to master the different clinical techniques. I can now report that a Class II composite requires about the same or slightly less time for me to place than a similar amalgam.

Your third-party payment companies will not like to hear my suggestion. I am not in favor of high fees for most dental procedures, and I have always supported moderate fees that honestly represent the effort placed into the dental procedure. However, I believe the fees for most Class II restorations — regardless of the material used — are significantly too low. Compare the time involved and difficulty of procedure from a one-canal endodontic therapy, or a crown preparation and seating, to a large Class II restoration. The difference in income per unit time is immediately evident. It is difficult and time-consuming to prepare a tooth and place a high-quality Class II resin-based composite restoration, but our fees may be inadequate to represent the time and effort expended.

I suggest that you determine how long a typical Class II composite and a typical Class II amalgam require in your office. Compare these times with that required to accomplish a one-canal endodontic procedure or a crown preparation and seating. Adjust the fee per unit time for your posterior tooth restorations to more closely match the fee per unit time for the other procedures. It is apparent that the restorative costs should go up in many offices. I have placed the cost of a Class II amalgam about the same as the cost of a Class II resin-based composite. By doing so, the patient's selection of posterior tooth restorative materials is not based on cost. Please be aware that your third-party payment organizations may object to raising fees, so you may have to change these fees incrementally over a period of time.

A popular recent PCC video related to this subject is C501B, "Predictable Long-Lasting Class II Resin Restorations." This up-to-date video shows how to produce fast, easy, nonsensitive, predictable Class II resin restorations. For more information or to order, call (800) 223-6569, fax (801) 226-8637, or visit our Web site at

Dr. Christensen is a practicing prosthodontist in Provo, Utah. He is the founder and director of Practical Clinical Courses, an international continuing-education organization for dental professionals initiated in 1981. Dr. Christensen is a co-founder (with his wife, Rella) and senior consultant of Clinical Research Associates, which, since 1976, has conducted research in all areas of dentistry and publishes its findings to the dental profession in the well-known CRA Newsletter. He is an adjunct professor at Brigham Young University and the University of Utah. Dr. Christensen has educational videos and hands-on courses on the above topics available through Practical Clinical Courses. Call (800) 223-6569 or (801) 226-6569.

Dr. Christensen's views do not necessarily reflect the opinions of the editorial staff at Dental Economics.

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