Feedback

Periodontal Regeneration: Myth or Reality?

Editor's note:Occasionally, response to an issue or article featured in the Journal requires more than just the printing of a Feedback letter so that the issue or controversy can be further explored to benefit the understanding of our readers. The article "Periodontal Regeneration: Myth or Reality?" published in February 1999, presents such a circumstance. It is our belief that the reader should have the opportunity to review information pertinent to the controversy on this subject; thus, we have assembled the Feedback mini-forum that follows.
Readers are reminded that all scientific manuscripts published in the CDA Journal have received blind peer review by individuals on CDA's consultants list that is updated regularly by the Council on Dental Research and Developments, which is composed of clinicians and academicians throughout the state. An editorial decision to approve publication is not made until the author has presented a manuscript that either receives approval of the reviewers or has been modified so that it satisfactorily removes the basis for initial criticism upon further review prior to publication.

Letters on other topics follow.

The article "Periodontal Regeneration: Myth or Reality" presents a view that is significantly different from the current scientific thought and evidence on periodontal regeneration. It is stated that periodontal regeneration procedures are only slightly better than flap debridement, that improvements were not significantly enhanced by guided tissue regeneration, and that these procedures (bone grafting and guided tissue regeneration) may not provide patient benefits in terms of improved periodontal health.

The opinions expressed run counter to current periodontal research findings. In the article, the author chose to reference 54 articles, only one of which has been published since 1996. Most of the studies cited -- and many more -- were reviewed, compared, and critically examined at the 1996 World Workshop on Periodontics, sponsored by the American Academy of Periodontology, which brought together 135 participants from around the world.

At the 1996 World Workshop, periodontal research was evaluated and measured using an evidence-based approach, a comprehensive and rigorous literature evaluation process applied by scientists and clinicians. This methodology was used by participants in the World Workshop to assess the evidentiary status of periodontal and implant treatment. At the World Workshop, the Section on Periodontal Regeneration Around Natural Teeth evaluated 352 papers in the area of regeneration. The consensus findings of the section and all the other sections were sent to all members of the American Dental Association as a supplement to the September 1998 issue of JADA.

The following highlights of the consensus findings of the Section on Periodontal Regeneration Around Natural Teeth differ greatly from the opinions in the article.

* Bone grafting: "Several bone replacement grafts have demonstrated significant clinical improvement. Well-documented human investigations have demonstrated periodontal regeneration with demineralized freeze-dried bone allograft."

* Barrier membranes: "Multiple studies using occlusive (barrier) membranes have demonstrated significant clinical improvement."

* Long-term stability: "Long-term studies of five years indicate that regenerative procedures result in periodontal stability in patients who are compliant with plaque control and receive effective supportive periodontal therapy at approximate intervals."

* Open flap debridement: "There is no evidence that open flap debridement techniques promote periodontal regeneration."

Further, a review of the current periodontal research from 1997 and 1998 published in the Journal of Periodontology (Vol. 68, Nos. 1-12; Vol. 69, Nos. 1-12) and the Journal of Clinical Periodontology (Vol. 24, Nos. 1-12; Vol. 25, Nos. 1-12) shows findings that are remarkably consistent with those of the World Workshop.

Barrier membranes -- 22 human studies:

* Fourteen studies showed clinical attachment gain greater than 3 mm.

* Four studies showed clinical attachment gain of 2-3 mm.

* Two studies showed clinical attachment gain of 1-2 mm.

In those studies that compared a barrier membrane technique to flap debridement, the barrier technique was 1-2 mm superior to open flap debridement in all the papers, except two pilot studies by the same research group in Sweden, which found the two procedures equal, with each procedure gaining only 1-2 mm of clinical attachment. It is interesting that the only recent study included in the review was one of these studies.

Bone allografts -- 11 human studies:

* Eight studies found an increase in attachment greater than 2 mm.

* One study reported an increase in attachment greater than 4 mm.

* Two studies reported the allograft equal to open flap debridement.

Molar furcations:

* Five studies found an increase in attachment of 2 mm or greater in buccal furcations.

The current scientific findings speak for themselves: Periodontal regeneration is a clinically significant therapeutic technique. It is one of many modalities of periodontal treatment and, logically, is not applicable to all clinical situations. Periodontal therapy is both science and art. The art being the appropriate and skillful application of the science. Periodontal diseases are complex and multifaceted clinical entities that require the clinician to bring to bear the entire range of therapeutic options. Today, periodontal regeneration procedures are important and predictable clinical therapies that enhance and improve treatment outcomes and provide for repair and reversal of the damage to the periodontium by periodontal disease in appropriately selected areas.

In evaluating periodontal therapy, we must not let our biases cloud our judgment. We must be willing to evaluate and accept emerging research even if the findings are not to our personal liking. Unfortunately, omitted and misrepresented in this paper has been the large body of evidence supporting periodontal regeneration as a significant clinical therapy.

Gordon L. Douglass, DDS
Sacramento, Calif.

As contributing editor to the February issue of the Journal of the California Dental Association, I asked Dr. William Becker to write the article on periodontal regeneration. Dr. Becker is a full-time practicing periodontist. He is not on the payroll of any company and is not a full-time academician. Dr. Becker is able to run clinical studies out of his office as well as contribute significantly to the periodontal literature. As a private-practice periodontist first and researcher second, Dr. Becker has worked extensively with bone grafts and barrier membranes and has a comprehensive knowledge of periodontal regeneration. He was one of the first to publish results on periodontal regeneration and, therefore, has some of the longest follow-up on these patients. Dr. Becker is frequently on the forefront of current thinking in the treatment of periodontal disease as is evidenced by his numerous clinical studies that have been reported in the periodontal literature.

In his review of regenerative procedures, Dr. Becker was not only honest about his personal results with the long-term use of periodontal regeneration, but also presented references from reviewed journals to further illustrate the possible shortcomings of regenerative therapy. He did not suggest that demineralized freeze-dried bone or barrier membranes not be used. He merely questioned whether gains reported from most comparative studies are so clinically and statistically significant as to compel all practitioners to use regenerative materials.

There is little doubt that in limited defects, some amount of regeneration is possible. Material from the 1996 World Workshop in Periodontology showed that there was significant gain in clinical attachment from regenerative procedures. However, as most of these studies were not comparative studies, little information is available on how these defects would have responded without regenerative materials. The Annals of Periodontology, which presented findings from the 1996 World Workshop,1 states that significant decreases in probing depth and gains in clinical attachment level and bone can be predictably anticipated when deep intrabony defects are treated with or without barrier membranes.

A review of the current literature shows that in those studies that compared a barrier membrane technique to flap debridement, the barrier membrane was 1-2 mm superior to open flap debridement in all the papers except two, which reported the two procedures to be equal. The question remains, are these gains so clinically and statistically significant to compel all practitioners to use these materials. Are these additional gains in clinical attachment stable over the long term? Do the additional 1-2 mm of attachment gain justify delaying necessary restorative treatment for an additional six to 12 months? After regenerative therapy, can I predictably expect defects to fill?

Finally, I would like to quote a guest editorial by Drs. Pamela McClain and Robert Schallhorn from the January 1999 Journal of Periodontology, Page 103. Drs. McClain and Schallhorn have reported in the periodontal literature on long-term results utilizing regeneration with bone grafts and bone grafts with barrier membranes and have been proponents of the use of regeneration in periodontal therapy. In this editorial, they state: "The variability in the degree of response to regenerative therapy helps maintain a cautious attitude regarding the state of the science and influence of other factors not yet clarified such as the impact of root trunk length and morphology, content of BMP, or other factors important to periodontal regeneration in the DFDBA, intraradicular morphology, and other factors not adequately delineated for their effect on the regenerative outcome." They go on the state: "Surrogate evidence of periodontal regeneration has been shown to be predictable in narrow two- and three-walled intrabony defects (IBD) using a variety of techniques and materials, while wide two- and three-walled IBD, one-wall hemiseptal, class II and III furcations, and horizontal/crestal osseous defects remain less predictable as evidenced by the variability of results in the literature."

With the knowledge that only a minimal amount of additional attachment gain may be achieved using regenerative materials as opposed to not using regenerative materials, with many defects responding less predictably and possible not holding up long term, I believe that as Dr. Becker suggested, in a clinical situation, we must question the current advantage of regenerative materials.

David F. Levine, DDS
Burbank, Calif.

The article, "Periodontal Regeneration: Myth or Reality?" does not imply that demineralized freeze-dried bone allograft (DFDBA) or barrier membranes not be used. The question we ask is, are gains reported from most comparative furcation studies so clinically and statistically significant as to compel all practitioners to use these materials. I think not. Significant decreases in probing depth and gain in clinical attachment level and bone can be predictably anticipated when deep intrabony defects are treated with or without barrier membranes.1

Is commercially available demineralized freeze-dried bone a bone-inductive regenerative material? There is a preponderance of scientific literature that questions the bone inductivity of this material. "Commercially available" is the underlying concept. There is no question that special preparations of DFDBA induce bone in ectopic sites (muscle) in mice and rats. Commercially available DFDBA is considered to be osteoconductive. Articles have appeared in peer-reviewed journals that demonstrate the shortcomings of DFDBA as an inductive material.2-10

Periodontics has made major strides during the past 20 years. We have improved surgical techniques for teeth and dental implants, are at the forefront of improving dental esthetics for our patients, and are investigating methods to regenerate tissues adjacent to teeth and dental implants. We are identifying systemic diseases related to periodontal disease, take a leadership position in preventive dentistry, and are capable of improving periodontal health for all forms of the disease. We have and will continue to share knowledge with all of our colleagues. We will continue to make significant progress for the benefit of our patients. In America, there is room for differences. General dentists as well as all specialists have the educational background to make informed decisions based on the current state of knowledge.

William Becker, DDS, MSD
Tucson, Ariz.

Kudos to Dr. Bob

Congratulations to Dr. Horseman on his article "Animal Welfare Acts" in the January 1999 issue. He says what needs to be said in a clear, firm, but amusing manner.

Francis V. Howell, DDS, MS
La Jolla, Calif.

No Case for Competency Assessment

In the editorial in the February 1999 issue of Journal of the California Dental Association, Dr. Jack Conley asserts that it is a "right thing" for the dental profession to acquiesce to some form of continuing competency assessment. By the use of the word "right," one is led to believe he is speaking of a moral issue, yet the preponderance of his concerns appear to focus on the alleged nebulous repercussions to the economic status and reputations of the profession if this is not accepted. The only evidence supporting a moral concern is found in the quote from former U.S. Sen. George Mitchell: "We became convinced there is today, a public system which isn't protecting the public."

For me, as I hope all in the dental profession would agree, the moral and ethical issues are paramount. This is not to say the economic consequences and public perception are unimportant. The case has not been made for dentists supporting an increase in government meddling in our profession. The government is already too expensive, too intrusive, and usually incompetent.

J. Dennis Lewis, DDS
Brea, Calif.

References

1. Garrett S, Annals of Periodontology, American Academy of Periodontology, Section 7, pp 622-66, 1996.
2. Aspenberg P, et al, Failure of bone induction by bone matrix in adult monkeys. J Bone Joint Surg 70, 1988.
3. Pinholt EM, et al, Alveolar ridge augmentation by osteoinductive materials in goats. Scand J Dent Res, 1992.
4. Pinholt EM, et al, Titanium implant insertion into dog alveolar ridges augmented by allogenic material. Clin Oral Implants Res 5, 1994.
5. Becker et al, Variations in bone regeneration adjacent to implants augmented with barrier membranes alone or with demineralized freeze-dried bone or autologous grafts: A study in dogs. Int J Oral Maxillofac Implants 10:2, 1995
6. Shigeyama Y, et al, Commercially prepared allograft material has biological activity in vitro. J Periodontol 66, 1996.
7. Becker et al, Human demineralized freeze-dried bone: Inadequate induced bone formation in Athymic Mice. A preliminary report. J Periodontol 66:9, 1995.
8. Schwartz Z, et al, Ability of commercial demineralized freeze-dried allograft to induce new bone formation. J Periodontol 68, 1998.
9. Schwartz Z, et al, Ability of commercial demineralized freeze-dried allograft to induce new bone is dependent on donor age but not gender. J Periodontol 69, 1998.
10. Schwartz A, et al, Human recombinant BMP-2 to inactive commercial human demineralized freeze-dried bone allograft makes an effective composite bone inductive implant material. J Periodontol 69, 1998.