Purpose: Some reports show a benefit of coating dental implants with hydroxyapatite (HA), and others assert that resorption of the HA coating compromises long-term implant survival. This study examined this controversy by systematically reviewing all the current literature that reports the outcomes of HA-coated implants in human clinical trials.
Materials and methods: A systematic Medline computer search of the English literature yielded 45 human clinical trials that reported on the outcome of HA-coated implants. Eleven studies that met specific inclusion criteria were selected for detailed analysis. The studies were divided into 2 groups. One group of 5 studies reported implant survival using overall percentage, and another group of 6 studies reported implant survival using life-table analysis.
Results: The overall percentage survival rates ranged from 93.2% to 98.5%, with 4 to 8 years of follow-up. The cumulative survival rates for studies that used life-table analysis ranged from 79.2% to 98.5%, with 5 to 8 years of follow-up. The yearly interval survival rates reported for the studies using life-tables were variable but remained above 90% and did not show a progressive or precipitous decrease with increasing years of follow-up.
Conclusions: The survival rates reported for HA-coated implants were similar to the survival rates reported for uncoated titanium implants. If resorption of the HA coating causes late failure of implants, the yearly interval survival rates should have decreased with increased years of follow-up. This decrease was not observed in the longitudinal human clinical trials that met the selection criteria for this study. Detailed analysis of these clinical trials did not show that HA-coating compromises the long-term survival of dental implants.