Effects of a local single dose administration of growth hormone on the osseointegration of titanium implants

Background The aim of the present study was to evaluate the effect of different concentrations of growth hormone (GH) on endosteal implant’s surface at the early stages of osseointegration. Material and Methods Sixty tapered acid-etched titanium implants were divided into four groups: i) Collagen, used as a control group; and three experimental groups, where after collagen coating, GH was administered directly to the surface in varying concentrations: ii) 0.265 mg, iii) 0.53 mg, and iv) 1 mg. Implants were placed in an interpolated fashion in the anterior flange of C3, C4 or C5 of 15 sheep with minimum distance of 6 mm between implants. After 3-, 6- and 12-weeks of healing samples were harvested, histologically processed, qualitatively and quantitatively assessed for bone-to-implant contact (BIC) and bone area fraction occupancy (BAFO). Results Statistical analysis as a function of time in vivo and coating resulted in no significant differences for BIC and BAFO at any evaluation time point. Histological evaluation demonstrated similar osseointegration features for all groups with woven bone formation at 3 weeks and progressive replacement of woven for lamellar bone in close contact with the implant surface and within the implant’s threads. Conclusions A single local application of growth hormone to the surface of titanium implants did not yield improved implant osseointegration independent of healing time. Key words:Growth hormone, osseointegration, low density bones, metallic implants, sheep, bone-to-implant contact.