IN RECENT YEARS, THE FOCUS of dental implant research has been the nat
ure of the bone-implant interface associated with osseointegration, ye
t the transgingival portion of endosseous dental implants has received
little attention. The purpose of this study was to determine the atta
chment of human gingival fibroblasts to three different implant materi
als: commercially pure titanium, non-porous hydroxyapatite, and porous
hydroxyapatite. Cell attachment was quantified by radiolabeling gingi
val fibroblasts with tritiated thymidine and counting attached cells b
y liquid scintillation following incubation for periods of 20, 40, and
60 minutes. Additional studies coating implant surfaces with fibronec
tin were also performed. The nature of the implant material itself app
eared to affect the number of attached cells. Determined on a surface
area basis, fibroblast attachment was greatest to titanium followed by
non-porous hydroxyapatite. Porous hydroxyapatite demonstrated the lea
st amount of fibroblast attachment. When incubated with fibronectin at
a concentration of 50 mug/ml, no increase in the number of cells atta
ched to the various implant materials was observed. A small but statis
tically significant increase in the number of fibroblasts attached to
porous hydroxyapatite at 40 minutes was observed when implant material
s were pre-treated with fibronectin.