Interview about teeth remineralization with Dr. Rella Christensen

Dr. Dalin: Remineralization of teeth has become a hot subject in dentistry.

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Jeffrey B. Dalin, DDS, FACD, FAGD, FICD

For more on this topic, go to www.dentaleconomics.com and search using the following key words: remineralization of teeth, Dr. Rella Christensen, fluoride, compliance, Dr. Jeff Dalin.

Dr. Dalin: Remineralization of teeth has become a hot subject in dentistry. Recently, we have seen the development of many new products. This month I will discuss this topic with Dr. Rella Christensen. I understand we need calcium, fluoride, and phosphate so that remineralization can take place. Dr. Christensen, do we need specific forms of these substances?

Dr. Christensen:That is a question we are trying to answer. We are performing a large, randomized, controlled clinical trial that uses full-banded orthodontic patients as the study model. We are testing seven commercial products, plus there is a control group. The products in the evaluation are:

  • Prevident 5000 ppm F dentifrice
  • Clinpro 5000 ppm F dentifrice
  • Varnish America 5% NaF varnish
  • Prevident 5000 and Varnish America used on the same patient
  • MI Paste Plus calcium phosphate paste that also contains 900 ppm F
  • HealOzone, which delivers 2,100 ppm ozone gas
  • Epic xylitol mint or fruit tablets

The control is the orthodontic offices' usual oral hygiene instruction protocol. This study involves 40 children, ages 9 to 17, in each group. We are asking if these products will prevent the demineralization so commonly seen due to poor oral hygiene during 18 to 24 months in brackets and wires. Our study follows the children from banding day to debanding day, and will quantify the demineralization that occurs.

Dr. Dalin: I thought that fluoride was used to create a more acid-resistant mineral layer on the outer surface of a tooth. I now read that perhaps the fluoride does more for this remineralization than the calcium and phosphate. Is this the case?

Dr. Christensen:About 15 years ago, we performed a clinical trial with what is now Prevident 5000 Plus dentifrice after it came to market. We showed — quite conclusively — that by using scanning electron microscope monitoring of the surface, the 5,000-ppm F therapy restored the surface of acid-etched enamel to its original appearance after about three months. The timing appeared to be dose-dependent and related to how many times per day the subject brushed with the product.

Dr. Dalin: What are some of the similarities and differences between the products in your study?

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Dr. Rella Christensen
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Dr. Christensen:The similarity among the products is that they all claim remineralization potential. Compliance is an issue with some of the treatments. Prevident 5000 and Clinpro 5000 are both 5,000-ppm fluoride dentifrices, delivering about five times more fluoride than conventional 1,000-ppm OTC dentifrices that can be purchased at grocery and discount stores. We must rely on patient compliance with these products. Both have good flavor. We have study subjects brush thoroughly just before bedtime, as well as expectorate and not rinse after use in order to retain residual fluoride in the oral cavity overnight.

Both the 5% NaF Varnish America and the HealOzone (2,100 ppm applied using a vacuum-molded tray to each arch separately for 60 seconds) are applied at each adjustment appointment about every six to seven weeks. So compliance is not really an issue even though we have specific instructions for after-varnish application, which does require compliance.

These instructions include no eating for two hours after application, then eating only soft foods and no brushing or flossing until the next morning to keep the varnish in place as long as possible.

MI Paste Plus is a special calcium phosphate formulation that includes 900-ppm fluoride. The paste is applied after brushing just before bedtime, using the fingertip for generous application. The children use all five flavors, then select the one or two flavors that are their favorites. This procedure requires compliance to brush and apply nightly.

The xylitol tablets are used six times a day to deliver six grams of xylitol. Compliance is necessary, but the hope is that the tablets taste good so the children will remember to use them.

Dr. Christensen:I believe Colgate was the first to develop a commercial product that solved this problem with Prevident 5000 dentifrice. I believe this was the innovative part of the product. Clinpro 5000 is a different formulation. Clinically, our study is comparing it directly with Prevident 5000. It should be interesting to see if any or all of the seven products we are testing can decrease or prevent the demineralization that is so commonly seen after orthodontic treatment.

Dr. Dalin: Have you found it is better to brush these products on directly or should patients load them into bleach trays and leave the products in place for five to 10 minutes per application?

Dr. Christensen:Compliance is a huge issue. You can have an efficacious formulation, but if people will not use it, there is no benefit. We have found that we have best compliance with dentifrice, the varnish, and HealOzone, which we apply at every adjustment appointment. When you ask people to do things beyond routine tooth brushing, they must first remember to do the brushing and then push themselves to actually spend a few additional moments at it.

Dr. Dalin: How effective have these products been with regard to fading white, hypocalcified spots?

Dr. Christensen:Our study asks the products to prevent demineralization rather than correct it. Frankly, we have not found any treatment that removes white lesions, unless we include microabrasion as part of the treatment. The chalky white appearance comes from an alteration in light diffraction when mineral is lost from enamel and not corrected by what we refer to today as remineralization. This is why our work began with the goal of prevention.

Dr. Dalin: Is there anything else you would like to discuss?

Dr. Christensen:I think it is critical for clinicians to seek clinically controlled studies to document product claims before involving patients with the cost and time commitment of using remineralization products. Several of the products in our study are fairly costly. I think it is reasonable for patients to expect results when they spend much to achieve something and trust their dentist to know what will work for them. Most of the products we are testing have not been tested in large, controlled clinical trials. Lab studies are useful to companies as they develop products, but with remineralization, you can never duplicate in any lab protocol what happens in the oral cavity in real life. We are seeking products that overcome patients' poor nutrition and poor oral hygiene to prevent demineralization.

Dr. Dalin: Thank you, Dr. Christensen. I think we are seeing some great advances in ways we can help patients achieve better oral health. But I realize there are many claims being made that need to be backed up with good, solid, clinically controlled studies. I await the results of your study, as well as the studies of others who are testing these products.

Rella P. Christensen, RDH, PhD, cofounded and directed Clinical Research Associates, Inc., a nonprofit research foundation, for 27 years. Currently, she is CRA's Board Chairman. She practiced dental hygiene for 25 years, and founded the dental hygiene program at the University of Colorado. She earned a PhD in physiology, emphasis on microbiology, from Brigham Young University.

Jeffrey B. Dalin, DDS, FACD, FAGD, FICD, practices general dentistry in St. Louis. He is the editor of St. Louis Dentistry magazine, and spokesman and critical-issue-response-team chairman for the Greater St. Louis Dental Society. Dr. Dalin is a cofounder of the Give Kids A Smile program. Contact him at jeff@dfdasmiles.com.

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