Ask Dr. Christensen

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 regarding new techniques or products to Dr. Christensen, please send an email to

If you have a dental emergency, please do NOT email Dr Christensen. Please consult a local dentist.

Question ...
I've heard that systemic antibiotics can be used for treatment of periodontal disease. How effective are these drugs, and can they be substituted for conventional periodontal therapy?

Answer from Dr. Christensen ...
Most people who live into their mature years need some type of periodontal therapy. However, many of them will not accept conventional therapy.

Various nonconventional periodontal treatments have evolved, and research reports on conservative therapy conclude that clinical results can be impressive. The most commonly used nonconventional periodontal therapies include the following:

  1. Systemic therapies. Research has shown that 20 mg of doxycycline hyclate (Periostat®) delivered two times per day for up to nine months produces a measurable reduction in periodontal pockets as an adjunct to scaling and root planing. Some clinicians feel nine months is longer than necessary. The results produced by systemic antibiotics have been known for years, but enzyme suppression has been popularized over the last several years by the product Periostat® by Collagenex, (888) 339-5678. You might think that use of doxycycline over several months would create resistant strains of microorganisms and the associated mucous membrane challenges in those patients taking the medication. However, it is stated that the small doses of doxycycline hyclate in this product do not produce a systemic antibiotic result; they produce an antienzymatic result, reported to reduce the effect of collagenase and, therefore, reduce ongoing periodontal disease. Reports from dentists using the product have been encouraging.
  2. Local antibiotic application. This concept was considered ineffective in the past. However, in recent years, the efficacy of various antibiotic agents placed into periodontal pockets has been verified by clinical research. Example products are Atridox by GlaxcoSmithKline, (800) 652-5625, PerioChip by Dexcel Pharma Inc., (866) PERIOCHIP, and Arestin by OraPharma, (866) ARESTIN. These products are inserted into a periodontal pocket with probing pocket depth (PD) > 5 mm, allowed to release their medication, and gradually dissolve. Atridox contains the antibiotic doxycycline. PerioChip contains the antimicrobial chlorhexidine gluconate in a biodegradable matrix of hydrolyzed gelatin. Arestin is a bioresorbable powder with the active ingredient minocycline. The result of the therapies listed is a reduction in depth of the periodontal pockets.
  3. Rinses. The well-known and long-used chemical chlorhexidine gluconate has a well-proven record to reduce periodontal inflammation and encourage gingival health. Also well-known are two major side effects: taste reduction and superficial tooth staining. I suggest that chlorhexidine rinse be used as the initiating rinse in conservative periodontal therapy, followed by other types of rinses after a few weeks. The product Tooth and Gum Tonic (Dental Herb Company, (800) 747-4372) is a potent solution containing essential oils and herbs with proven effectiveness in conservative periodontal therapy. Many other rinses can be used subsequently.

Conservative periodontal therapy is an alternative for people who will not accept conventional therapy. The concepts described previously should be used for those patients instead of doing nothing. In my opinion, appointments should be about two to three months apart, and all three categories of treatment listed above should be used in addition to routine scaling, root planing, education, and motivation toward oral hygiene improvement.

More on this subject from Dr. Christensen is available on the video C199A — "Atridox, Periodontal Therapy" and C599B — "Periodontal Therapy, Conservative and Effective." Call Practical Clinical Courses at (800) 223-6569 for information.

Question ...
Are flowable resins advisable in proximal boxes of Class 2 resin-based composite restorations?

Answer from Dr. Christensen ...
A routine problem with Class 2 resin-based composites has been postoperative tooth sensitivity. This challenge may be overcome by using conventional "total etch" bonding agents correctly or by using 'self-etching primers." However, some dentists have reported that the "total etch" bonding products are conducive to unpredictable postoperative sensitivity. Reports indicate that flowable resin placed in the proximal box forms of Class 2 resin restorations reduces potential postoperative sensitivity. Numerous reasons for the observed reduction in sensitivity have been described: The flowable resin fills the open dentinal canals that have not been filled totally by the bonding agents; thus, the flowable resin provides a flexible buffer between the resin-based composite restorative resin and the tooth structure. Whatever the reason, the result is evident: Postoperative tooth sensitivity is reduced when flowable resins are used.

Are there other reasons to use flowable resin in proximal box Class 2 composites? Clinicians have noted that the buccal and lingual gingival portions of the restorative resin in proximal box forms often have voids. There is a potential to reduce these voids by use of flowable resin before placing the restorative resin. A thin coat of flowable resin placed and cured before placing the restorative resin, or placed and cured at the same time as the restorative resin, has been reported to reduce the presence of voids at these locations.

One negative characteristic of using flowable resins in proximal box forms of Class 2 resins is the lack of radiopacity of some of the flowable resin brands. I suggest that practitioners select flowable resins that are relatively radiopaque — Flow-It! by Jeneric Pentron, (800) 551-0283 or Tetric Flow by Ivoclar Vivadent, (800) 533-6825. Lack of radiopacity of flowable resins in proximal box forms can be misleading for future dentists as they try to determine if recurrent dental caries has occurred.

In summary, flowable resins in proximal box forms may help reduce postoperative tooth sensitivity and seal cavo-surface margins on the box form, but use of these materials is not mandatory.

More on this subject from Dr. Christensen is available on the video C501B — "Predictable Long-Lasting Class 2 Resin Restorations." Call Practical Clinical Courses at (800) 223-6569 for information.

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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