IMPLANT FAILURES

L E T T E R S

LETTERS ADA welcomes letters from readers on topics of current interest in dentistry. The Journal reserves the right to edit all communications and requires that all letters be signed. The views expressed are those of the letter writer and do not necessarily reflect the opinion or official policy of the Association. Brevity is appreciated.

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THIRD MOLARS

Thank you for Drs. Stephen Eklund’s and James Pittman’s article concerning third-molar removal patterns (“Third-Molar Removal Patterns in an Insured Population,” April JADA). I am a practicing dentist of 34 years, and I was somewhat surprised to see such a disparity of opinion between general practitioners. I am an advocate of early removal of unerupted third molars at an appropriate time. My rationale for this is mainly, but not exclusively, that the periodontal status of erupted third molars in middle-aged adults is seldom ideal. Further, I think that these teeth may compromise the health of adjacent teeth. As a practical matter in my office, we find that it is much easier to motivate a parent to have an adolescent’s third molars removed than to persuade a middle-ager to do the same. Also, I don’t think that the difference in cost to the insurance companies should be a factor in this decision. I don’t know how much time the authors are able to spend

dealing with patients directly. I am willing to bet that if they would ask the people in their school’s hygiene department to take a look at the recall patients who have erupted third molars—and if they would do this for a year or so—they possibly would come away with a changed attitude. Thank you for the well-balanced Discussion section. I heartily agree that a set of guidelines could be a benefit to us all (although I wouldn’t want to be on the committee drafting them!). There is an adage in football that there are many possible outcomes for a forward pass, and only one of them is good. This has been my experience with third molars. Fred Knapp, D.D.S. Independence, Mo. Authors’ response: We very much appreciate Dr. Knapp’s interest in our article and the opportunity to discuss further the issues that he raises. It was not the intent of the article to suggest which approach to third-molar removal is best, but rather to let dentists see the differences in their practice patterns so that a more thorough discussion of the topic can take place within the profession. While a profession never can unilaterally decide what is best for the public, we nevertheless firmly believe that the focus of these kinds of discussions must be within the profession. Our principal focus was on the early prophylactic removal of asymptomatic, unerupted third molars. Dr. Knapp’s point about oral hygiene problems around erupted third molars as a rationale for extraction—and

the difficulty in motivating middle-aged adults to have these teeth extracted—is a somewhat different issue. The removal of teeth because of oral hygiene difficulties is perhaps best done on a patientby-patient, tooth-by-tooth basis, with those patients who can be motivated to adequate oral hygiene having the option to retain these teeth. It is difficult to see how judgments on ability to maintain adequate oral hygiene can be made for an adolescent before the tooth has erupted. Finally, we agree with Dr. Knapp that insurance should not determine how patients are treated. Treatment decisions should be tailored to the needs and wants of each patient. If a needed and desired procedure happens not to be covered by insurance, the patient surely can decide to purchase it anyway. Also, if patients would not otherwise want a procedure, insurance should not dictate that they have it. Insurance is best seen as a means to help people to buy what they need and want, not something that dictates those needs and wants. Stephen A. Eklund, D.D.S, M.H.S.A., Dr.P.H., James L. Pittman, D.D.S., M.S. Ann Arbor, Mich. IMPLANT FAILURES

“Implant Failures Associated With Asymptomatic Endodontically Treated Teeth” by Drs. David Brisman, Adam Brisman and Mark Moses (February JADA) is a clinical report about four implant failures that the authors claim resulted from their proximity to asymptomatic endodontically treated teeth.

JADA, Vol. 132, July 2001 Copyright ©1998-2001 American Dental Association. All rights reserved.

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While it is commendable that clinicians share experiences from which useful information may be gained, it is very important that conclusions be drawn from sound, scientifically supported evidence—not just four clinical cases. The issue of possible effects of endodontically involved teeth on the placement of adjacent implants is important and needs to be investigated. These four cases, however, do not appear to add any significant information and actually pose several problems, such as questionable placement of the implants and lack of preoperative evaluation of the adjacent endodontically treated teeth. Case 1. The patient was a smoker who “ceased smoking for three months before implants were placed.” Did he start smoking again immediately after the implant placement? The implant was placed in very close proximity to the endodontically treated tooth. Did the osseous preparation in fact impinge on the periodontal ligament, or PDL, space? Had the bone completely healed following the extraction? The second implant is several millimeters away from the tooth and the apicoectomy site appears to have healed. Perhaps the tooth healed because no treatment was needed on this tooth initially. Case 2. The information about this patient is very difficult to evaluate. The lack of preand postimplant radiographs of the first implant makes it impossible to verify the authors’ claim that “the asymptomatic endodontically treated mandibular right second premolar was the cause of the implant failure.” The second implant was clearly impinging on the PDL 854

space of the endodontically treated tooth. After the removal of the implant, the gutta-percha tracing of the sinus tract leads to an area several millimeters below the apex of the endodontically treated tooth with no apparent lesion associated with its root apex. Is the gutta-percha marker actually in a drainage tract, mental foramen or perhaps in granulomatous tissue in the implant extraction site? Case 3. Once again, the implant clearly is placed very close to the endodontically treated tooth. After removing the implant, the tracing of the drainage tract goes directly to where the implant appears to have touched the root of the tooth. Clearly, when implants are placed in contact with adjacent teeth, bone cannot be expected to develop between the tooth and the implant. Case 4. The fourth patient experienced an infection following implant placement. This infection responded to surgical débridement around the implant and administration of antibiotics, yet nothing reportedly was done to the endodontically treated tooth. Remarkable resolution was observed within two weeks! How did the adjacent tooth play a role in this case? While there is not abundant literature regarding endo-implant interactions, several interesting articles may shed some light. The article by Shaffer and colleagues1 mentioned by the authors concluded that “if endodontic pathosis is identified, root canal treatment or extraction should be initiated before implant placement to prevent microbial contamination of the implant during healing.” That is common sense, and other articles such as the report by

Novaes and colleagues2 show that careful alveolar curettage performed at the time of extraction results in implant integration, but with less implant-bone contact. Readers cannot determine by reading the JADA article how well the extraction sites had healed prior to implant placement. In an article by SchwartzArad and colleagues,3 bone defects from teeth extracted for periodontic and/or endodontic infections were shown to be managed but required careful attention to provide adequate osseous support for the implants. Recently, a research project reported by Shabahang and colleagues4 demonstrated that there was no difference in osseointegration in implants placed either adjacent to teeth with healthy periradicular tissues or infected teeth. While no one at this time would recommend placing implants near infected teeth, the results of this research project indicate that infected adjacent teeth may play less of a role in failures than other factors. Many reasons for biologicial implant failures were discussed in the article by Esposito and colleagues5 that the authors quoted, including the presence of infected implants. It is quite possible that implant infection was the etiologic factor in all four cases presented by the authors, yet this possibility apparently was not considered. In summary, the American Association of Endodontists’ position is that teeth with untreated endodontic infection should be treated prior to placement of an adjacent implant. The quality of the root canal treatment of an endodontically

JADA, Vol. 132, July 2001 Copyright ©1998-2001 American Dental Association. All rights reserved.

L E T T E R S

treated tooth should be carefully evaluated as part of the examination before treatment planning that may involve implant placement rather than after the implant fails. With the emphasis that we currently place on evidencebased approaches to treatment, it is important that speculation be carefully identified as speculation with little or no scientific support. Jeffrey W. Hutter, D.M.D., M.Ed. President, American Association of Endodontists Chicago 1. Shaffer M, Juruaz D, Haggerty P. The effect of periradicular endodontic pathosis on the apical region of adjacent implants. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1998;86:578-81. 2. Novaes AB Jr., Vidigal GM Jr., Novaes AB, Grisi, MF, Polloni S, Rosa A.. Immediate implants placed into infected sites: a histomorphometric study in dogs. Int J Oral Maxillofac Implants 1998;13(3):422-7. 3. Schwartz-Arad D, Grossman Y, Chaushu G. The clinical effectiveness of implants placed immediately into fresh extraction sites of molar teeth. J Periodontol 2000;71(5):839-44. 4. Shabahang S, Bohsali K, Kaplanis N, Torabinejad M. Effects of periradicular lesions on osseointegration of dental implants (abstract OR24). J Endod 2001;27(3):220. 5. Esposito M, Hirsch J, Lekholm U, Thomsen P. Differential diagnosis and treatment strategies for biologic complications and failing oral implants: a review of the literature. Int J Oral Maxillofac Implants 1999;14:473-90.

Author’s response: I fully agree with Dr. Hutter that a case report cannot replace a good scientific research study. But in the dental community it is very important that we share our experiences, if for no other reason than to stimulate interest in performing research where the literature is lacking. As Dr. Hutter states, very few articles have been published on the communication between implants and natural teeth. There is also a surprising lack of literature on the long-

term histological condition of the apex of asymptomatic endodontically treated teeth. As for the cases presented, it is true that the limitations of the illustrations do not allow the reader to evaluate the surgeries performed. But the surgeons involved have placed an abundance of implants, and we are confident that the PDL was not involved. Of course, there are many reasons for implant failure, but these cases stood out because they did not seem to fit any of the other common criteria for implant failure. Again, I agree with Dr. Hutter that to draw too many conclusions from case studies is inappropriate. JADA is a source of communication in our community and hopefully will inspire more work in this very important area. David L. Brisman, D.M.D. New York City REMEMBER TO REMEMBER

Dr. Meskin’s analysis of the “oversupply” days is right on target in “Back to the Future” (April JADA). We must continue to keep fresh in our members’ memories the difficulty that many of us who started our careers in the 1970s encountered. For the last two years, I have found it necessary to remind our delegates of the problems that many of us faced in the 1970s. The increasing demand for young dentists to buy the existing practices of older members is not a valid reason for increasing the number of dental students. Certainly there is a question of access, but this has more to do with distribution than supply. I will continue to raise this issue on the floor of the House of Delegates of the

American Dental Association. This editorial, following right on the footsteps of Dr. Meskin’s editorial regarding the sale of soda and candy in the schools, highlights the great loss JADA will face when Dr. Meskin leaves. [Editor’s note: Dr. Meskin steps down as JADA editor at the end of this year.] Please continue to fight the good fight, wherever you find yourself. Frederic Sterritt, D.M.D. Belle Mead, N.J. ACCURACY QUESTIONED

I was disappointed by the lack of accuracy of many of the comments and the misinterpretation of our published data in “Efficacy of Subantimicrobial Dosing With Doxycycline: Point/Counterpoint” by Drs. Gary Greenstein and Ira Lamster (April JADA). I plan on publishing an article with other academics and clinicians addressing each of these points in detail. However, challenging each point is not possible in a rapidly published, and by necessity brief, letter to the editor, so at this time I will restrict my comments to the last section of their article, “Update: An Additional Clinical Trial.” The authors’ statement that the data in my recent publication1 “contradicts the usual findings in the periodontal literature” clearly indicates that the authors completely misunderstood a major goal of our study. Our study was designed to be different from most other longitudinal studies described in the periodontal literature. As a unique aspect of our study, we deliberately selected for measurement only those pockets that repeatedly exhibited pathologically elevated, host-

JADA, Vol. 132, July 2001 Copyright ©1998-2001 American Dental Association. All rights reserved.

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