Open Letter to the Dental Profession on the Changing Definitions of Osseointegration.
OSSEOINTEGRATION --- OSSEO-HYPE ---OSSEO-HYSTERIA --- OSSEO-POLITICS
OSSEOINTEGRATION --- CHANGING DEFINITIONS
Throughout the first fifteen years of Brånemarks research publications (1969-1984), only one definition of osseointegration was used. This definition was succinctly stated in his 1984 article.
1984 DEFINITION - Brånemark et al., JOMS, Vol. 42, No. 8, 1984: "Osseointegration means a direct contact, on the light-microscopic level, between living bone tissue and the implant."
1985 DEFINITION - Brånemark, Albrektsson, Zarb, Tissue Integrated Prostheses, Quintessence Publishing Company: "A direct structural and functional connection (must exist) between ordered living bone and the surface of a load-carrying implant."
CHANGE: Added that the implant must be in function
1986 DEFINITION - Albrektsson, Zarb et al., JOMI, Vol. 1, No. 1, 1986: "Oseointegration is a histological definition and only partially a clinical and radiographic one. An implant can only be judged as osseointegrated in the context of a continuum of observation...Hence the proposal that both clinical evidence of mobility and radiographic bone response be judged after a substantial period of implant service."
CHANGE: Added that the implant could only be considered osseointegrated if it had been osseointegrated for "a substantial period of implant service" (Catch 22 definition).
CONTRADICTION: The same article stated that "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."
The same article further stated by way of reference to " Brånemark, P-I, Personal Communication, 1986: these results indicate that any implant losses after the first one to two years of function seem to be unlikely, provided osseointegration has occurred."
1987 DEFINITION - Albrektsson et al., JPD, May 1987: "A properly osseointegrated implant at the cortical passage should have a minimal direct bone contact of 90 percent of the implant surface. This high degree of osseointegration should completely surround the circumference of the cylindrical implant."
CONTRADICTION: An abstract by Helm et al. presented at 1987 International Preprosthetic Surgery Symposium concluded that the Brånemark Implant "had less than a quarter of the endosseous area in direct contact with bone."
1988 DEFINITION - Zarb et al., University of Toronto Dental Journal, Vol. 1, No. 2: "Osseointegration is a clinical application of a biologically investigated host bone to the placement of threaded, unalloyed titanium implants using a meticulous surgical procedure."
CHANGE: Implies that implant design ("threaded) and material ("unalloyed titanium) are significant restrictions in extrapolating the predictability of osseointegration to other designs and materials that have demonstrated osseointegration.
CONTRADICTION: Brånemark stated in his 1977 article (referenced above) that the "...design of the implant...is of secondary importance to the mechanism of anchorage in the jaw bone...The careful handling of tissue and the use of an inert non-contaminated material are the prime prerequisites for osseointegration."
1988 NOBELPHARMAS POSITION ON OSSEOINTEGRATION
#1. CLAIM - Undated letter (received May 1987) to profession from the President of Nobelpharma USA: "Our marketing and advertisement claims will be based upon truth and scientific data, not on marketing hype."
UNTRUE STATEMENT - Nobelpharmas 1988 booklet entitled, "The Smile that Says Everything Brånemark System": "Here is the only system that uses the revolutionary method of osseointegration to attach a dental prosthesis permanently to the very jawbone itself."
UPDATEe: Subsequent to first printing of this literature review, Nobelpharma retracted this statement in a letter and withdrew the booklet from circulation"
1988 NOBELPHARMAS POSITION ON LONG-TERM RESULTS
#2. CLAIM - Undated letter (received May 1987) to profession from the President of Nobelpharma USA:
FACT - Nobelpharma 1988 Product Catalog - Page 14, "Self-tapping fixtures - NEW ARTICLES."
Nobelpharma introduced two new self-tapping implant designs and a new surgical protocol eliminating the need for pre-threading of bone. One of the implants (conical design) looks like the self-tapping Screw-Vent Implant from Core-Vent Corporation.
1988 NOBELPHARMAS POSITION ON LONG-TERM PREDICTABILITY OF OSSEOINTEGRATION
Undated letter (received May 1987) to profession from the Product Manager of Nobelpharma USA:
#3. CLAIM - "Even though a fixture osseointegrates with the bone, it does not mean it can withstand the load of 5, 10, or even 20 years and more of normal function like the Brånemark System."
FACT - Article by Albrektsson, Zarb et al. stated that 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."
FACT - Nobelpharma advertisements continually claim 96% Upper Jaw Bridge success. When and if they reference this claim, it is to group 2B (1-4 year follow-up) documented in Adells articles (Int. J. Oral Surg., 1981; JPD, August, 1983). The same articles showed 5-12 year Upper Jaw Bridge success to be under 90%. Adell, in a presentation at Harvard School of Dental Medicine, November 1987, reported on the success of Upper Jaw Bridges in group 2, now with 6-10 year follow-up. The success rate has dropped to under 91%.
1977 BRÅNEMARK CLINICAL DETERMINATION OF OSSEOINTEGRATION
Brånemark et al., Scand J Plast Reconstr Surg 1977;11 (Suppl 16): "To diagnose the state of an osseointegrated implant, we decided to use mainly three methods, i.e. clinical stability of each implant, roentgenographic appearance of the incorporated jawbone and roentgenographic marginal bone height."
1987 Albrektsson Clinical Determination of Osseointegration - JPD, May, 1987
CONTRADICTION: "Unfortunately, the presence of clinical stability cannot be taken as conclusive evidence of osseointegration."
CONTRADICTION: Albrektsson article questioned the relevance of radiographic evidence to the determination of osseointegration "Radiographs demonstrating a seemingly direct contact between bone and implant have, by others, been cited as evidence of osseointegration."
OSSEOINTEGRATION COMPARISON STUDY:
CORE-VENT vs. BRÅNEMARK IMPLANT
Abstract Presentation AADR/IADR Meeting, March 10, 1988, Montreal
OSSEOINTEGRATION OF BIOTES AND CORE-VENT IMPLANTS
IN NON-HUMAN PRIMATES
O.R. Beirne, L.B. Lum, M. Dillinges, T. Curtis
Univ. of Calif., San Francisco, CA, University of Washington, Seattle, WA
Brånemark has proposed that the Biotes dental implant predictably replaces teeth by forming a direct connection with bone (osseointegration). Several implants, including Core-Vent Implants, adhere to the requirement to achieve osseointegration, but few studies have directly compared Core-Vent with the Biotes placed in non-human primates.
The left and right 1st and 2nd mandibular molars were removed from 5 Macca Mulatta monkeys. After 15 weeks of healing, 2 Biotes and 2 Core-Vent implants were placed, one each on the right and left mandible where the teeth had been removed. After 18 weeks, 1 animal was killed and crowns were placed on each implant in the remaining 4 animals. Two animals were killed 5 months and 2 were killed 12 months after placing the crowns.
Clinical examination revealed that all implants were present without infection or mobility. Block sections containing the implants were removed, fixed in acetone and embedded in plastic. The blocks were sectioned through the long axis of the implants. Light microscopic examination revealed that both the Biotes and Core-Vent implants osseointegrated. Evaluation 5 and 12 months after placing the crown showed that the bone response to the two types of implants was the same and the implants maintained osseointegration.
OSSEOINTEGRATION LITERATURE REVIEW PROVIDED COURTESY OF CORE-VENT CORP.