AMALGAM BONDING

LETTERS in teaching institutions make governmental politics seem like a child’s game. The competition for promotion is based primarily on research and publication, so that teaching students takes a back seat. In addition, full-time faculty are obligated to serve on numerous committees and spend a disproportionate amount of time in administration, and without an independent income, a decent standard of living is difficult to achieve. Unfortunately, society places actors and sports figures at the top of the ladder and teachers near the bottom. Dentists undergo the sacrifices and hard work required to enter the profession to be self-employed and responsible for their own success. Unless universities and the professional schools they control adopt a different attitude toward the value of their faculty and the worth and importance of dentistry, good dental teachers will be scarce. James L. Dannenberg, D.D.S. Philadelphia TREATING BRUXISM AND CLENCHING

I read with interest the article (“Treating Bruxism and Clenching,” February JADA) by Dr. Gordon J. Christensen. While Dr. Christensen did emphasize several of the most important therapeutic modalities (for example, splint therapy), there is no mention of the importance of the patient being informed about mandibular rest position (with teeth out of contact, only lips touching) and the use of isokinetic stretching exercises.1 In the mandibular rest position with the teeth slightly out of contact and only the lips touching, it is impossible to contract

the masticatory muscle, thus avoiding myalgia or load in the temporomandibular joint with the resulting joint pathology of disk dislocation, synovitis or capsulitis. The patient is told that usually the teeth should only be in contact during chewing and swallowing predominantly. The isokinetic exercises referred to are based on an article authored by Lewit and Simons.1 The principle involved is maintaining skeletal muscles in a stretched position for an extended period; in the case of masticatory muscles, [that is] 20 seconds for five times or a total of 100 seconds. This greatly relaxes the previously shortened muscle fibers. With the masticatory muscles being relaxed in this fashion, it is much easier for the patient to use mandibular rest position. These subjects are discussed in detail in an article I authored.2 Based on my practice of 53 years, much of it involving TMD research and treatment, emphasizing the importance of rest position and isokinetic exercises have been invaluable in “controlling bruxism.” James H. Quinn, D.D.S. Metairie, La. 1. Lewit K, Simons DG. Myofascial pain: relief by post-isometric relaxation. Arch Phys Med Rehabil 1984;65:452-6. 2. Quinn JH. Mandibular exercises to control bruxism and deviation problems. J Cranio 1995;13(1):30-4.

Author’s response: I appreciate Dr. Quinn taking the time to share his experiences with all of us, and I congratulate him for his many years of research and treatment in the TMD area. I agree with the concepts he presents. Gordon J. Christensen, D.D.S., M.S.D., Ph.D. Provo, Utah

AMALGAM BONDING

I have some comments on the January JADA cover story (“Clinical Evaluation of Amalgam Bonding in Class I and II Restorations,” by David B. Mahler, Ph.D., and John H. Engle, D.D.S.). The authors conclude that after three years of clinical service, amalgam bonding for “traditional” Class I and Class II restorations had no effect on postoperative sensitivity or marginal integrity. After bonding amalgam for 10 years with a tremendous reduction in sensitivity, I was surprised. I see the operative word here is “traditional.” From the five restorations pictured, I surmise the author’s use of “traditional” to mean conservative. I, therefore, do not dispute the postoperative sensitivity conclusion. However, this is comparable to studying the use of seat belts and air bags in 10-miles-perhour collisions. I personally have found a dramatic reduction in postoperative sensitivity. My opinion may be anecdotal, but after 15 years’ experience of not bonding amalgams, I started using adhesive on my deep amalgams, and complaints of postoperative sensitivity have been reduced remarkably. Whether it is the acid etch or the adhesives I am not certain, but again, postoperative sensitivity is significantly reduced. I have thrown my Dycal away. I do not bond small (traditional) amalgams, as I find Gluma or Micro Prime work well on them. In addition, the beauty of amalgam bonding is that you do not do “traditional” prepara-

JADA, Vol. 131, June 2000 Copyright ©1998-2001 American Dental Association. All rights reserved.

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LETTERS tions. The traditional amalgam preparation requires undercuts for retention. Bonding amalgams eliminates the need for mechanical retention. You can prepare teeth as you would for an inlay, remove all undermined enamel and provide almost onlay-type strength to a tooth. How many times have you removed amalgam from a cracked tooth to find amalgam packed under a cusp? Thomas O. Williams, D.D.S. Dayton, Ohio Authors’ response: We appreciate Dr. Williams’ letter in which he shared his experience on amalgam bonding with us. In response, we should start by pointing out that the reason for conducting this study was our concern that dentists were using amalgam bonding for all amalgam restorations, and we wondered if bonding had any merit specifically for traditional Class I and Class II amalgam restorations. The term “traditional preparations” was intended to include intercoronal restorations of different widths (see the table on page 44 of January JADA). Although most would be considered conservative-tomoderate in size, some large and deep restorations were included. However, their numbers were not considered sufficient either to refute or confirm Dr. Williams’ improved success with the use of bonding agents for the treatment of “deep restorations.” The use of bonding vs. the use of calcium-hydroxide materials or the use of bonding amalgams in unretentive inlaytype preparations as proposed by Dr. Williams were not eval720

uated in this study. Therefore, to respond to the efficacy of these alternative procedures would be speculation on our part. Our experience using both published and anecdotal information made us aware of the sensitivity factors that affect microleakage and postoperative sensitivity. We have shown from previous studies that the factors of amalgam selection, mixing ratios and condensation techniques play a significant role in the development of sensitivity; and while certain bonding agents and techniques may compensate when these factors have not been properly addressed, it was not our goal to evaluate the interaction. Once again, we wondered if bonding had any merit for traditional Class I and Class II amalgam restorations. The results of our study could not demonstrate merit for this application. We could turn Dr. Williams’ analogy around by saying that if we were dealing only with 10-m.p.h. collisions (traditional Class I and Class II restorations), then why are air bags (bonding agents) necessary? John H. Engle, D.D.S. David B. Mahler, Ph.D. Portland, Ore. ANTIBIOTIC PROPHYLAXIS

I am writing to point out the misleading nature of the March JADA article (“Antibiotic Prophylaxis in Dentistry: A Review and Practice Recommendations”) by Darryl C. Tong, B.D.S., M.S.D., and Bruce Rothwell, D.M.D., M.S.D. This article appears to be a change in protocol recommended by the ADA/American Heart

Association. I believe immediate communication and clarification are mandatory. Mark Peppard, D.D.S. Austin, Texas Authors’ response: We regret your confusion. Our intention was to produce an article that was consistent with the title—a review of antibiotic prophylaxis and recommendations for practitioners. The relatively recent [1997] change in protocol by the AHA and ADA, and the similarly recent recommendations by the ADA and the American Academy of Orthopaedic Surgeons were used as an opportunity to review the scientific literature on the whole topic of antibiotic prophylaxis. It is clear from that review that many of the commonly accepted reasons for antibiotic prophylaxis employed in dental practice are not supported by adequate scientific evidence. Bruce R. Rothwell, D.M.D., M.S.D. Seattle Darryl C. Tong, B.D.S., M.S.D. Dunedin, New Zealand THE $80-PER-HOUR OFFER

I recently received an invitation to join yet another dental managed care plan. This one was even more intriguing than most. It showed complex mathematics proving that their plan guaranteed me $80 per hour for treating their patients. I don’t know how many of you fellow dentists have ever figured out your hourly overhead; I suggest you do so as soon as possible. I have a suburban practice, one associate, four auxiliaries and an hourly

JADA, Vol. 131, June 2000 Copyright ©1998-2001 American Dental Association. All rights reserved.