Effects of growth hormone on initial bone formation around dental implants: a dog study

OBJECTIVE: The aim of this study was to evaluate the effects of topical application of growth hormone (GH) on the osteointegration of dental implants in dogs at 5 and 8 weeks after surgery. MATERIALS AND METHODS: Mandibular premolars and molars were extracted from 12 Beagle dogs. Four screw implants were placed in each mandible. Before implant placement, 4 IU of GH were applied to the test sites (TS); no treatment was applied to control sites (CS). Morphometric parameters, bone-to-implant contact (BIC), peri-implant connective tissue, interthread bone and newly formed bone were measured. The Student's t-test for was used for statistical analysis of data obtained. RESULTS: After 5 weeks of treatment, BIC values varied slightly between 34.33 ± 2.35% (CS) and 35.76 ± 2.96% (TS). Interthread bone tissue was 64.08 ± 8.68 at CS and 72.86 ± 2.93 at TS, with statistical significance (P<0.05). Bone neoformation was 72.53 ± 4.54 at the CS and 80.74 ± 1.65 for the GH group, these being statistically significant differences (P<0.05). After 8 weeks, BIC had slightly increased for the GH group (36.47 ± 3.09 vs. 39.61 ± 2.34). Interthread bone was 80.57 ± 2.28 at the CS and 82.58 ± 2.44 at the GH site, which was statistically significant. Bone neoformation was 88.09 ± 1.38 at CS and 91.01 ± 1.52 at TS, showing statistical significance (P<0.05). CONCLUSION: Topical application of 4 IU of GH like a biomimetic agent at the moment of implant placement has no significant effects on the BIC at 5 and 8 weeks, although bone neoformation and inter-thread bone values did increase significantly.