In the June 1986 column, "Dentists and the Law," by Dr. Edwin J. Zinman, the following question was posed by a dentist "considering employing osseointegration": "If the patient is advised preoperatively [of the risk of failure], am I legally protected, since long-term research evidence now is available to prove the effectiveness of osteointegrated implants?"

Apparently, Zinman has been misinformed as to the spelling, definition and research regarding osseointegration. The dentist was inquiring regarding osseointegration, not the "Scandinavian device" referred to by Dr. Zinman and currently marketed under the name "Biotes" or "Brånemark Implant System." This is the only system that restricts sale to "the select few specialists." Osseointegration is a term defined by Dr. P.-I. Brånemark [1] in 1984 as "direct contact on the light-microscopic level between living bone tissue and the implant." It is a biological phenomenon, not a trademarked term, patented process, or unique physical occurrence specific to the implant used in the Swedish research. Since the Swedish clinical research did not evaluate different materials, designs, surfaces or insertion techniques in controlled studies, it can be interpreted as proving only the biological principle that a bone-titanium oxide interface, once established, offers the opportunity for long-term stability. The legacy of the Swedish research was stated in a recent article [2] by Albrektsson and Zarb (co-authors with Brånemark on a textbook on osseointegration): "The Brånemark results...clearly underscore the basic concept of osseointegration as being the major if not the exclusive reason for a successful long-term dental implant attachment."

Dr. Zinman may be relying on Biotes’ marketing rhetoric rather than the published research in formulating his opinion as to the significance of the "17-year success rate." Adell [3] reported on 4,100 implants but, for reasons of statistical analysis, omitted 2,139 implants, including all of the implants with observation periods of greater than ten years. A review of the statistics of the first six years of clinical research [4] reveal a 62% failure rate in the upper jaw and 35% failure in the lower jaw. Of the 1,961 implants reported by Adell, 944 had observation times of one to four years, and it was this short-term segment of the study that is often referred to as representative of the entire research period, as evidenced by Brånemark’s published statement [5] in a press release:

In 20 years of clinical testing, Biotes has been 99 percent successful in the lower jaw and 95 percent successful in the upper jaw.

I take issue with Dr. Zinman’s pejorative comments characterizing other osseointegrated implants as "newer experimental implant devices" and as "copycats," "clones," or "imitation implants." The Core-Vent Implant, introduced in 1982 and covered by US patent #4,431,416, has been referred to as "conceptually unique" by Albrektsson, Zarb et al. [2]. This article also stated that the "...Brånemark implantation procedure has been...criticized for being complicated and expensive." The Core-Vent Implant offers the predictability of osseointegration, simplified surgical procedures, and versatile prosthetic applications –– at a cost that is affordable to both dentist and patient.

The Core-Vent Implant is now in its fifth year of clinical use. Animal research [6] and a human specimen [7] evaluated histologically after being in function for two years confirm that the Core Vent Implant achieves osseointegration. Clinical results of 100 consecutively placed Core-Vent Implants were reported by Lubar and Katin [8], with 98% achieving and maintaining osseointegration over a three-year period (57 had been in function for at least two years). The fact that the Core-Vent System is user-friendly was confirmed by Messer et al. [9], who reported on the achievement of osseointegration with all the first 25 Core-Vent Implants placed, with only two failing to integrate with the first 60 [10]. Patrick [11] reported a 97% incidence of osseointegration with 250 Core-Vent Implants.

Informed Consent: Dr. Zinman pointed out in his August 1985 column in Dental Management that "Some courts have viewed literature-supported success rates as misleading if the treating dentist’s success rate differs markedly." He has, therefore, answered the question of whether a dentist, just starting the Swedish system with little or no clinical experience of his own, can infer to his patients that he will achieve the same success rate as the researchers who inserted thousands of implants. Adell’s published research reported on Brånemark implants placed in the anterior of edentulous jaws to support fixed bridges, and does not necessarily translate to other locations or applications. Albrektsson et al. [2], referring to the Brånemark implant, said, "The placement of osseointegrated dental implants posterior to the mental foramina must be regarded as experimental, since no five-year results have been published for such implants...the use of the Brånemark screw as an individual replacement is, so far, based on anecdotal reporting exclusively."

Standard of Care: Another legal issue raised by Dr. Zinman’s comments is that of standard of care. Approximately 60 universities and teaching hospitals and over 3,000 general dentists and surgical specialists are using the Core-Vent System; one recent market analysis gave it a greater than 50% share of the entire implant market. If the selection of an implant system is to be a legal issue rather than the following of the surgical protocol prescribed for the system chosen, then Core-Vent could arguably be the standard of care by the predominance of its use.

Practicing dentists should base decisions about implantology on published research and the clinical experiences of their colleagues, rather than on legal intimidation based on misinformation. DM

REFERENCES

1. Brånemark, P-I et al.: An experimental and clinical study of osseointegrated implants penetrating the nasal cavity and maxillary sinus. J Oral Maxillofac Surg, Vol. 42, No. 8, August, 1984.

2. Albrektsson, T., Zarb, G., Worthington, P., Eriksson, A.R.: The long-term efficacy of currently used dental implants: A review and proposed criteria of success. Int J of Oral Maxillofac Impl, Vol. 1, No. 1, 1986.

3. Adell, R.: Clinical results of osseointegrated implants supporting fixed prosthesis in edentulous jaws. J Prosthet Dent, Vol. 50, No. 2, August, 1983.

4. Brånemark, P-I et al.: Osseointegrated implants in the treatment of the edentulous jaw. Scandinavian Journal of Plastic and Reconstructive Surgery, Supplementum 16, 1977.

5. Brånemark, P-I: Nobelpharma, Inc. press release, 1985.

6. Lum, L.B., Beirne O.R.: Viability of the retained bone core in the Core-Vent Dental Implant. J Oral Maxillofac Surg 44:341-345, 1986.

7. Niznick, G.A.: Osseointegration –– an idea whose time has come. Destinations, Vol. X, No. 2, 1986.

8. Lubar, R., Katin, R.: Three-year clinical results with Core-Vent Implants. Abstract of Presentation at LSU Implant Symposium. March, 1986.

9. Gingrass, D., Messer, E., Ryan D., and Sewall, S.: Osseous ventegration: A preliminary study. Core-Venture, Vol. 1, 1986.

10. Messer, E.: Core-Venture, Vol. 1, 1986.

11. Patrick, D.: Core-Venture, Vol. 1, 1986.