Histomorphometric analysis of half apatitite-coated implants in humans. A pilot study

Aim of the study

This human study was able to compare the features of osseointegration of hydroxyapatite-coated implant surfaces with those of non-coated surfaces simultaneously on the same threaded titanium implants.

Materials and methods

Eight implants whose surfaces were half coated were fitted and submerged in 4 patients (two per patient). After 1, 3, 6 and 12 months of healing they were removed by block dissection and assessed histometrically.

Results

It was noted that at 1, 3 and 6 months the hydroxyapatite (HA) surface provided better quantitative bone-implant contact (91,73 % against 37,37 % at 3 months) and also better qualitative results (less immature bone and more lamellar bone in contact with HA at 6 months). However, these differences seemed to be reduced by 12 months and, even at 3 months, areas of partial resorption in the thickness of the HA coating was observed. (It should be noted that one of the implants was lost after two weeks).

Conclusion

At least to a certain extent, this human study, involving few implants, confirms the short term advantages of HA-coated implants. A significantly more rapid percentage of bone-implant contact occurred (after 1 month) as well as earlier bone maturation.

Commentary

It would be interesting to confirm whether these differences remain over a longer period of time (3 to 5 years) and after loading, especially if the HA happens to become resorbed, together with the clinical consequences.