Factors affecting peri-implant tissue reactions

Abstract

Screw- shaped titanium implants are today routinely used m the substitution of lost teeth. In this thesis some of the biological factors related to the long-term survival and maintenance of dental implants were studied.

The first arm of these studies was to evaluate the neutrophil activation around teeth and dental implants (Papers I & II). Secondly we wanted to evaluate the clinical radiographic and microbiological status of implants after long-term. function m partly edentulous patients (Paper III). The long-term treatment outcome of implant treatment m fully edentulous was also compared to that m partially edentulous patients (Papers III & IV). The third and final purpose of these studies was to investigate the influence of smoking, a history of periodontitis and a specific host-response pattern on the occurrence of late fixture loss and marginal bone loss around dental implants (Papers IV & V).

Papers I and II showed that the inflammation around implants m partly edentulous patients induced a stronger neutrophil reaction than did the inflammation around implants m edentulous patients albeit similar clinical appearance and absence of significant differences m the microbiota. Paper III, showed that marginal bone loss around implants after ten years of function in partly edentulous patients was limited and comparable to that m edentulous jaws. There was no major difference in the microbiota colonising teeth and implants. In Paper IV, 143 consecutively treated patients were evaluated retrospectively after five years of function of implants. Only 2% of the fixtures were lost during function. No correlation was found between bone loss around implants and teeth. A history of periodontitis did not influence mar~ bone loss around implants Smoking was not found to correlate with marginal bone loss at neither implants nor teeth.

In Paper V a site-specific inflammatory reaction around implants with peri- implantitis rather than a patient-associated host-response was found in patients with failing implants Patients with peri-implantitis harboured high levels of periodontal pathogens, Actinobacillus actinomycetemcomitans Porphyromonas gingivalis Prevotella intermedia, Bacteroides forsythus and Treponema denticola.

In conclusion Although the inflammation around implants m partly edentulous patients induces a stronger neutrophil reaction, than M m the edentulous ones, the marginal bone loss after long-term function in the former is limited and similar to that in edentulous jaws. In patients treated for periodontal disease stable periodontal and peri-implant conditions can be maintained during long term function The periodontally-associated microbiota constitute a risk for future development of peri-implantitis In patients with a history of periodontitis Le. individuals who previously have shown a tissue destructive inflammatory response, this risk is more pronounced.