Ask Dr. Christensen

Oct. 1, 2005
In this monthly feature, Dr. Gordon Christensen addresses the most frequently asked questions from Dental Economics® readers.

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 e-mail to [email protected].

Question ...

I have been out of school for five years, and am building a new office. The expense is enormous. I am wondering whether I should include several operatories in my office, in spite of the expense, or build only three (which is what I use now - two for me plus one for the hygienist).

Answer from Dr. Christensen ...

As indicated by your desire to build a new office, you have probably developed a busy practice within the confines of the three-operatory space you currently have available. It is probably your desire to expand the practice to provide more services to patients and more income for your family. I will assume that is the case, and I suggest that you develop the following concept.

Build the physical facility large enough for five or six operatories. Should you equip all of these operatories? No, I suggest that you start in the new facility with the same orientation of the past - three operatories, two for you and one for the dental hygienist. Will three operatories allow you to have optimum productivity? In my opinion, most dentists are capable of using more than three operatories, if they use expanded-function personnel to the advantage of their patients and the overall productivity of the practice.

You need not equip the extra operatories at this time. You can allow the practice to grow, your own organizational ability to increase, and your involvement with expanded staff function to increase. As these developments occur, you will soon need another operatory, and eventually, another one. Additionally, your ability to use more expanded functions will be directly related to your interest, the practice laws in your area, and your ability to attract and educate staff. Increasing expanded staff activity increases your service potential, your income, and your need for more operatories. Equip the extra operatories as the need arises, thus deferring the cost of equipping them at a future time, but still having the space for expansion.

The cost of building, renting, or leasing the space of the empty operatories during this growing time is insignificant when compared to the cost of moving to another office in the future because of lack of space.

In other words, build, rent, or lease a larger space than you think you need, and equip it as you continue to develop your practice.

Our newest video, V4709 “Dr. Christensen’s Fantastic Practice-Building Techniques,” answers many questions about how to increase the activity of an existing practice or develop a new one. For more information, contact Practical Clinical Courses at (800) 223-6569, or visit our Web site at

Question ...

I am confused by the comments I hear from various sources on the best cement to use for posts when restoring an endodontically treated tooth. Should I use resin or resin-modified glass ionomer, or something else?

Answer from Dr. Christensen ...

Post and core fabrication has changed significantly in the past few years. The concept has evolved from custom-cast posts and cores, to prefabricated metal posts with buildups of amalgam or resin-based composite, to fiber-reinforced, resin-based composite posts with composite buildups.

Retentive pins have fallen into disuse in many practices because of observations related to these pins producing cracks in tooth structure during their placement. I suggest not using stainless steel pins because of their hardness and rigidity and their predisposition to crack teeth. However, I strongly support use of pure titanium pins, such as the Filpin (Filhol Dental). These relatively “soft” pins do not crack tooth structure during placement, and they do assist in developing antirotational and retentive properties in the buildups.

In recent years, the most popular cement type for posts has been resin, and the most popular brands have been Panavia F and ED Primer from Kuraray. However, the introduction of the self-etch primer/resin combination cements has influenced the market significantly. RelyX Unicem (3M ESPE), Maxcem (Kerr), and Universal Resin Cement (Pulpdent) eliminate the need for a separate acid/primer liquid. This characteristic has attracted the attention and use of many practitioners.

It is easier and faster to cement a post with one of these resin-cement combinations than using a cement that requires a separate application of the acid/primer solution. Additionally, in crown cementation over vital teeth, the self-etch primer/resin-cement combinations have been shown to have more predictability for lack of postoperative tooth sensitivity when compared to the brands that have a separate acid/primer liquid. RelyX Unicem and Maxcem are rapidly becoming the most popular resin cements for post cementation.

A significant point relating to post cementation and retention of posts is often overlooked. The drills supplied with the post systems produce an extremely smooth channel inside root canals. Is this smooth surface conducive to optimum post cementation? No, the internal surface of the smooth channel should be roughened using a coarse diamond on a low-speed handpiece before cementing the post.

In summary, to answer your question, I suggest using one of the self-etching/resin cements with a properly roughened root channel to achieve optimum retention with a fiber-reinforced, resin-based composite post.

One of our new videos, V19-08 “The Best Posts, Cores, and Build-Up Techniques,” demonstrates in closeup, live, clinical scenes, the many new, exciting, and logical changes from previous post and core procedures.

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.

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