Specimens were immediately fixed in 10% neutral buffered formalin and processed for histologic analysis. After dehydration, samples were infiltrated with a methyl-methacrylate resin from a starting solution 50% ethanol/resin and subsequently 100% resin, with each step lasting 24 h. After polymerization, the blocks were sectioned and then ground down to about 40 μm. Toluidine blue staining was used to analyze the different ages and remodeling pattern of the bone. The histomorphometric analysis was performed by digitizing the images from the microscope via a JVC TK-C1380 Color Video Camera (JVC Victor Company, Yokohama, Japan) and a frame grabber. The images were acquired with a × 10 objective over the entire implant surface. Subsequently, the digitized images were analyzed by the image analysis software IAS 2000 (Delta Sistemi, Roma, Italy).

For each section, the two most central sections were analyzed and morphometrically measured. The histomorphometric parameters calculated were the % bone-to-implant contact (%BIC) and the bone volume (%BV).

In both iliac crests of each animal, a bone sample was harvested close to the implant sites. The bone samples collected were analyzed in order to establish the bone volume percentage (basal %BV).

Biomechanical (VAM, RT, and ISQ) and histomorphometrical data (BIC% and BV%) of test and control groups were statistically compared by the T test using a dedicated software (GraphPad Prism 6 - www.graphpad.com).