Ask Dr. Christensen

June 1, 2003
"Recently, I've read: "Light augments tooth whitening with peroxide" (Tavares M, Slultz J. et al, JADA 134 (2) 167-175). This seems to be supportive of using lights with in-office bleaching.

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 ...
"Recently, I've read: "Light augments tooth whitening with peroxide" (Tavares M, Slultz J. et al, JADA 134 (2) 167-175). This seems to be supportive of using lights with in-office bleaching. I've assumed that light application used with in-office bleaching was only a marketing tool, with little clinical value. Unfortunately, I'm not certain as to what mechanism for whitening is truly happening with the lights ..." (This question has been shortened and rearranged from the original form).

Answer from Dr. Christensen ...
Over many years Clinical Research Associates (CRA) has studied the effect of light and heat on bleaching. The latest of their studies was published in the most recent CRA Newsletter (March 2003), in which we reported on the characteristics of several in-office bleaching systems using light. The following quote includes part of the CRA conclusions from that newsletter: "Use of lights according to the manufacturer's directions did not improve lightening for any system tested." Systems tested in the CRA study were: LaserSmile, LumaArch, Niveous, Opalescence Xtra Boost, PolaOffice, Rembrandt 1 Hour Smile-Whitening Program, and Zoom. Tests on BriteSmile have not yet been completed. Further scientific information on the lack of the effect of lights will be published in a bleaching supplement to Compendium next month. As with any concept, what actually happens and what the patient thinks is happening may be two different things. In these studies, light use did not speed or increase the bleaching over the use of bleaching chemicals alone. Therefore, as you stated in your question, there is little reason to use lights with bleaching except for marketing and "special effects." Unfortunately, it appears that in the eyes of some manufacturers and dentists, the marketing influence of lights is more important than their actual influence on the bleaching procedure.

Dr. Rella Christensen has been a pioneer in vital-tooth bleaching research. She recently stated that it is possible that a scientist, at some time in the future, will discover an additive to bleaching gels or solutions that will allow light or heat to speed or increase bleaching. As each new bleaching system comes on the market and alleges that their light enhances the bleaching effect, unbiased noncompany research must be performed to see if the claims are true. Research is underway on new bleaching-system brands to see if any recent progress has been made on the ability of lights to enhance the bleaching procedure.

Question ...
The tooth-bleaching concept is confusing to me. Almost all of the current products and bleaching concepts claim to be the best. Which product and which method for tooth bleaching will provide the most adequate bleach?

Answer from Dr. Christensen ...
I was bleaching vital teeth long before the concept became popular, and the techniques I have used have varied across all of the currently available techniques, as well as a few that have been abandoned. My beliefs are based on both research and clinical practice.

I was very pleased when the at-home bleaching method was introduced. The at-home technique allows patients to share in the responsibility for the procedure. No longer do I have to devote an operatory to bleaching. As a result, my productivity in clinical dentistry has increased significantly. Under supervision of a dentist, the patient is able to monitor the degree of bleaching, the tooth sensitivity that occurs, the changes in color of teeth relative to restorations, and the various other side effects that occur with any bleaching procedure.

The active bleaching ingredient in all current bleach concepts is hydrogen peroxide, delivered in many forms. It has been shown that no one technique delivers a more profound bleach than any other. It also has been shown that no one technique is more effective at bleaching than any other.

The main decision to make when considering bleaching techniques is whether or not you want to bleach in or out of your office. I prefer supervised, at-home bleaching. When using the at-home concept, chair time can be devoted to other procedures that require in-office activity. Fees for the supervised at-home procedure can be moderate or even low. Patients are in control of the level of bleaching desired, and bleaching can be slowed if untoward side effects occur.

Most dentists are using 10 percent or 15 percent carbamide peroxide in trays, either during the day or at night, with periodic evaluations by the dentist or a staff person. However, many patients like the Whitestrips (Crest) concept because it is so easily accomplished at any time during the day. Some dentists prefer the in-office approach, and I cannot criticize their choice. All bleaching methods are effective, and the method you choose should be based on your own beliefs and the scientific research you have read that you feel is trustworthy.

The following two new PCC videos will help your patients and your enjoyment of practice. We invite you to view them. They are V4798, "Advice for the Ideal Practice, What Every New Dentist Should Know," and V4796, "Dr. Christensen's Most Frequent Failures and How To Avoid Them." They are available in VHS and DVD formats. Contact PCC at (800) 223-6569, by fax at (801) 226-8637, or go online to

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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