The Influence on Osseointegration of Immediate Functional Loading on Single Crowns: A Randomized, Double-Blind, Split-Mouth Controlled Clinical Trial with Histomorphometric Evaluation.

PURPOSE: To evaluate the influence of immediate loading on the osseointegration and bone density of implants placed in a healed alveolar bone crest and supporting single crowns. MATERIALS AND METHODS: Two solid titanium transmucosal miniimplants were placed in the distal regions of the mandible in 14 patients. One mini-implant was immediately functionally loaded, whereas the other was left unloaded. After 2 months of healing, biopsy samples were retrieved and the levels of new bone, old bone, and total bone (new + old) were assessed. RESULTS: Histologic examination was performed on biopsies from 12 patients (n = 12). The new bone-to-implant contact percentage (BIC%) was 40.3% +/- 16.8% and 55.1% +/- 19.1% (P = .043) at the unloaded and loaded sites, respectively; in addition, the total BIC% was 44.9% +/- 17.0% and 59.5% +/- 18.8%, respectively (P = .034). The new bone density was 45.9% +/- 11.6% for the unloaded implants and 45.9% +/- 16.7% for the loaded implants (P = .622). CONCLUSIONS: Immediate loading had a positive effect on bone apposition at the implant surface, but no effect on bone density was observed after 2 months of healing.