BACTERIAL-COLONIZATION ON INTERNAL SURFACES OF BRANEMARK SYSTEM(R) IMPLANT COMPONENTS

The aim of the present study was to examine the microbiota on the inte rnal surface of the components of 28 Branemark implants(R) in 10 parti ally edentulous patients who had been treated with 1 fixed partial pro stheses each. The prostheses had been in function for 1 to 8 years. Th e fixed prostheses were checked for mobility and removed. The abutment screws were loosened and classified as stable, easily removed or loos e. Then, bacterial samples were obtained from the various internal sur faces of the implant system. Estimation and identification of the most predominant species was performed on the blood agar plates. Identific ation was based on Gram reaction, oxygen sensitivity and biochemical t ests. Internal surfaces of different components of the Branemark impla nts(R), after varying periods of function in the oral cavity, consiste ntly harboured a heterogeneous and primarily anaerobic microbiota. The individual samples showed a great variation. No relation could be see n between type and length of abutment, abutment stability, bone loss a nd type and number of microorganisms found in the samples. The flora c onsisted mainly of facultative and anaerobic streptococci, Gram-positi ve anaerobic rods such as Propionibacterium, Eubacterium and Actinomyc es species and Gram-negative anaerobic rods including Fusobacterium, P revotella and Porphyromonas species. There are reasons to suggest that this presence of bacteria is the result of (i) a contamination of the fixture and abutment components during the Ist and/or 2nd stage of im plant installation and/or (ii) a transmission of microorganisms from t he oral environment during function subsequent to bridge installation. (C) Munksgaard, 1996.