The present investigation evaluated the clinical and microbiological effects of long-term undisturbed plaque formation on peri-implant tissues. Four mongrel dogs were used in the study. The mandibular 3rd and 4th premolars were extracted. Three months later, four Brånemark implants (BR, n = 8) or Integral implants (IN, n = 8) were placed in the edentulous area of each dog. After another 3 months, an abutment connection was performed. Plaque control regiment was maintained for 30 days until the superstructure was placed (Day 0: baseline). Then the plaque control program was terminated to allow gross plaque accumulation. Clinical, radiographical and microbiological data were recorded at the baseline, and at 90 and 180 days after the termination of the plaque control. Values for the clinical indices such as probing depth, plaque index and bleeding on probing increased at day 90 on both the implant and tooth sites, and remained unchanged at day 180. Significantly more implant sites showed bleeding on probing than did tooth sites. Neither implants nor tooth sites showed clinically significant changes in mobility. No distinct bone resorption was observed over time by radiography. In microscopic morphological observations, cocci dominated at the baseline, and decreased by day 180, while the proportion of motile bacteria increased. In a culture study, black-pigmented anaerobic rods, which consisted predominantly of Porphyromonas gingivalis-like bacteria, were consistently found from the baseline to day 180. No Actinobacillus actinomycetemcomitans-like organisms were isolated. These results indicate that, although the long-term plaque accumulation did not cause marked periodontal destruction, the peri-implant tissue may be more susceptible to plaque accumulation than the periodontal tissue, and that teeth may serve as a reservoir for the bacterial colonization of the implant sulcus.
|Number of pages||8|
|Journal||The Bulletin of Tokyo Dental College|
|Publication status||Published - 1997 Feb|
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