Hydroxylapatite (HA)-coated implants have been the subject of great interest since the mid 1980s. Various clinical studies have shown that HA coatings lead to good clinical results over a time period of about five years.
A case of a removed HA-coated blade implant due to breakdown thereof was reported. Bone loss with a radiolucent appearance around the implant by the peri-implant inflammation was observed. A removed HA-coated titanium blade-form implant was examined using scanning electron microscopy (SEM) and electron probe X-ray microanalyzer (EPMA) for analysis of the main constructive elements.
The results were as follows:
1. Macroscopically and microscopically, the removed implant demonstrated loss of the HA-coating with the presence of the smooth titanium substrate.
2. For the EPMA data, the implant material mainly consisted of titanium with loss of the HA-coated layer. The remaining HA-coated layer was chiefly consisted of calcium and phosphate.
3. Analyses by EPMA indicated almost complete loss of mineral (HA) from the surfaces of the failed implant.
From the above results, it was considered that there may be significant depression of pH and the production of proteolytic enzymes along with bone loss and massive granulation tissue that results from the inflammatory process. Such an environment might be one of the causes for removal of the implants. The most important factor for preventing late complications with implant-prosthetic treatment is the peri-implant osseous and soft tissue conditions. A check of the implant-borne suprastructures and a thorough cleaning of the implants and any remaining natural teeth of patients who receive implant-prosthetic treatment are necessary.
