Bovine hydroxyapatite for maxillary sinus augmentation: analysis of interfacial bond strength of dental implants using pull-out tests

This study examines the effect of sinus lift surgery using bovine hydroxyapatite on the bone anchorage of titanium plasma flame-spray-coated cylindrical implants. A total of 54 implants were placed in the lateral bony antral walls of 27 mountain sheep. Host site augmentation was done simultaneously using bovine hydroxyapatite and autogenous cancellous bone from the iliac crest in 18 sinuses each. The bone walls of the remaining 18 sinuses received no augmentation. Pull-out tests were carried out at 12, 16, and 26 weeks. revealing a significant influence of the implants' residence time on Full-out strength (P=0.004). The implants of the non-augmented group and those of the group augmented using cancellous bone showed a linear increase in pull-out strength to 169.8 N and 523.7 N, respectively, until the 26th week. The implants of the group augmented with bovine hydroxyapatite exhibited the highest initial pull-out strength (325.1 N) that further increased to 521.8 N until the 26th week. All in all, this group showed a significantly greater pull-out strength than did the negative control group (P=0.03).