Changing concepts in clinical periodontology

In his first visit to Australia in more than ten years and first ever visit to New Zealand, Professor Jan Lindhe, from Goteborg University, toured five cities from Perth to Auckland in October and November, challenging the paradigms of periodontal and implant therapy.

The lecture tour, a collaboration between Astra Tech, The Australian Society of Periodontology, The Australasian Osseointegration Society and The Australian Prosthodontic Society, reached a total audience of more than 650.

Starting with data from the 1950's from Jens Werhaug, the then controversial studies from Ramfjord in the 1960's, as well as his own research with Sture Nyman, Professor Lindhe spent the first half of the full day program questioning and evaluating periodontal treatment modalities of today.

Several systematic reviews of randomised clinical trials showed that there are significant differences in the prognosis and long term benefit of various surgical and non-surgical forms of periodontal treatment. Professor Lindhe also discussed the systematic review as a form of efficacy study of various treatment modalities within medicine and dentistry.

He maintained that this form of review will become more and more important in the future, specifically from an insurance perspective, where insurers will review and compare the success and survival data of various treatment alternatives prior to committing any financial support. Although not in place yet, one would only expect that such evidence based socio-economic thinking will soon become the norm, especially in private sector insurance.

The process of osseointegration: Fiction and facts
The implant-related portion of the program focused on the factual process of osseointegration and the continued long-term maintenance of bone support surrounding dental implants. Professor Lindhe presented several studies on the Astra Tech system which challenged the original Albrektsson and Zarb criteria for success (1-2 mm of marginal bone resorption during the first year of function, and a further 0.2 mm per annum thereafter, Albrektsson and Zarb 1993). Five year data on 51 partially dentate patients from Wennstrm et al. (J. Clinical Perio, 2004; 31:713 -24) clearly showed superior results with .33 mm marginal bone level change the first year in function, with an additional .02 mm annually thereafter. This is in agreement with several other authors: Cecchinato et al, J. Clin Perio 2004, Gotfredsen et al., Clinical Implant Dentistry and Related Research, 2004, Palmer et al. Clinical Oral Implants Research, 2000.

However, the real challenge to current paradigms and the commercially driven ones in particular, came during the discussion of the osseous healing process of the edentulous ridge, and the separate process of osseointegration. Professor Lindhe once again followed the data to find out what is known about the biological response to implant installation in extraction sockets. After retracing the research step by step, the session ended with a word of caution - based on the experimental findings and early clinical data from several authors (Pietrokovski & Massler, J. Prosth. Dentistry, 1967; Schropp et al., International Journal of Perio and Restorative Dentistry; Botticelli, Berglundh & Lindhe, J. Clin Perio 2004; Arujo & Lindhe, J. Clin Perio, 2005), that immediate placement of implants in the extraction sockets of patients does not prevent resorption of the buccal bone. Osseointegration is a separate and independent process and the tissue resorbs as in a normal edentulous site, and may therefore create long term aesthetic issues for the patient.

Professor Lindhe concluded that more research is needed to understand the long-term implications of certain current treatment modalities, and that until more is known, clinicians should respect biology.