Sequential healing events of osseointegration at UnicCa(®) and SLActive(®) implant surfaces: an experimental study in the dog.

Abstract

To study the sequential events in osseointegration at implants with highly hydrophilic surfaces. All premolars and the first molars were bilaterally extracted in 12 Beagle dogs. After 3 months, full-thickness flaps were elevated and two different implants systems with various surfaces were randomly installed in the edentulous premolar region in one side of the mandible. One surface was acid etched and further modified with calcium ions (UnicCa(®)), while the other was sandblasted with large grits and acid etched (SLActive(®)). The flaps were sutured to allow a fully submerged healing. The surgery on the other side of the mandible and the sacrifices were planned in such a way to obtain biopsies representing the healing after 1, 2, 4, and 8 weeks (n = 6 per period). After one week of healing, new bone apposition was found at both surfaces with percentages of 6.9 ± 3.3% and 6.1 ± 4.6% at UnicCa(®) and SLActive(®), respectively. After 2 weeks, the percentages had increased to 29.1 ± 11.9% and 21.6 ± 14.3%, respectively. After 4 and 8 weeks of healing, mean values of 46.3 ± 7.3% and 58.7 ± 15.1% at UnicCa(®) and 51.2 ± 16.1% and 68.9 ± 15.4% at SLActive(®) surfaces were found, respectively. None of the differences in percentages were statistically significant. Concomitantly, the old bone was resorbed at both surfaces from about 21-22% after 1 week to about 4-6% after 8 weeks of healing. The osseointegration process onto moderately rough titanium implant surfaces of high hydrophilicity was very similar for two implant systems that were both nanotechnologically modified.