Histological and histomorphometrical study of connective tissue around calcium phosphate coated titanium dental implants in a canine model

Connective tissue reaction and collagen fiber orientation were evaluated on the calcium phosphate coated implants made by ion beam assisted deposition, and compared with the uncoated titanium implants. Twelve implants of each group were randomly placed in mandibles after 3 months of premolars extraction in beagle dogs. All the implants were firmly anchored in the bone and had no clinical signs of peri-implant inflammation after 3-month insertion. Histological sections showed that the gingival tissue was attached tightly to the implant surface and there was no significant difference in inflammatory cell invasion between the control and experiment groups. The probing depth in the calcium phosphate coated group was 1.9 ± 0.2 mm, less than in the control group (2.1 ± 0.2 mm) (p < 0.05). Newly regenerated vascular tissues were observed more around calcium phosphate coated implants than uncoated titanium implants. The gingival recession in the experiment group was less than in the control group, but there was no significant difference in tissue length between the two groups (p > 0.05). Collagen fibers at the inner zone of the connective tissue around calcium phosphate coated implant aligned mostly in oblique direction, while paralleled in uncoated titanium implant. Calcium phosphate coating was found to promote soft tissue regeneration and preventing gingival recession.