Premature loss of
dental implants is due, apart from mechanical factors, to germrelated
inflammation. Gaps and hollow spaces within the implant system, for example the gap between implant and abutment in the two-part implant system, may provide a bacterial reservoir causing or maintaining
inflammation. The bacterial spectrum involved is similar to that found in
periodontitis. This in vitro study aimed to scrutinise the capability of Porphyromonas gingivalis (DSM 20709), the bacterium blamed for inducing
peri-implantitis, to pass the implant/abutment gap in
titanium implant systems used for orthodontic anchorage and to remain vital in the interior. Additionally, the in vitro effectiveness of
gutta percha for gap sealing was examined. Twelve
titanium implants (Straumann, diameter: 3.3 mm, length 5.5 mm) were provided with abutments at a defined torque (20 Ncm), six of which were sealed with
gutta percha before screwing in the abutment. Subsequently the implants were placed in a nutrient
solution (thioglycolate boullion with haemin-
menadione solution) that contained Porphyromonas gingivalis. Microbiological specimens were sampled from the implant interiors after 24 and 72 hours and analysed using culture methods. There was evidence that penetration of the periodontal pathogen Porphyromonas gingivalis to the implant interior may occur as early as after 24 hours. Microbes were also detected in the interior of implants sealed with
gutta percha. The abutment/implant interface in vitro provides a microbiological leakage for the prospective
peri-implantitis-inducing bacterium Porphyromonas gingivalis. Survival of the bacterium is possible in the interior, so that development of a bacterial reservoir is assumed. This in vitro trial produced no evidence that sealing with
gutta percha is an effective means to prevent secondary bacterial colonisation in the implant interior.