M. Quirynen et al., THE INFLUENCE OF SURFACE-FREE ENERGY ON SUPRAGINGIVAL AND SUBGINGIVALPLAQUE MICROBIOLOGY - AN IN-VIVO STUDY ON IMPLANTS, Journal of periodontology, 65(2), 1994, pp. 162-167
THE INFLUENCE OF SURFACE FREE ENERGY on supra- and subgingival plaque
microbiology was examined in 9 patients with functional fixed prosthes
es supported by endosseous titanium implants. Two abutments (trans-muc
osal part of the 2 stage implant) were replaced by either a new titani
um abutment or a fluor-ethylene-propylene (FEP) coated abutment per su
bject. After 3 months of habitual oral hygiene, plaque samples were ta
ken. Supragingival plaque was examined by means of differential phase-
contrast microscopy, whereas for the subgingivial plaque additional an
alyses (DNA probes analysis, culturing) were performed. The subgingiva
l samples were taken by paper-points and by scraping of the subgingiva
l abutment surface. Differential phase-contrast microscopy showed a si
gnificant difference in plaque composition, especially when supragingi
val plaque was considered (P = 0.05). FEP coated abutments frequently
harbored more coccoid microorganisms, whereas spirochetes or motile or
ganisms were only detected around titanium abutments. Subgingivally, t
he number of colony forming units (CFU) in paper-points was comparable
for both types of abutments. If the to-the-abutment-adhering plaque w
as considered, the number of CFU was 5 times higher on the titanium ab
utments than on the FEP coated abutments. However, this difference did
not reach a statistical level of significance (P = 0.38). The DNA pro
be analysis of the subgingival plaque collected with paper-points show
ed a slightly higher frequency and concentration of perio-pathogens ar
ound the titanium abutments. However, the inter-substratum differences
were smaller than the inter-subject differences. The latter seemed to
be related to patient's dental status. These results indicate that lo
wering the surface-free energy of intra-oral hard surfaces results in
a reduction in bacterial colonization and in a retardation in its matu
ration in the supragingival area. For the subgingival area, the influe
nce of this surface characteristic is not as obvious.