Fractures of Hydroxyapatite‐Coated Blade Implants Connected With Natural Teeth. A Histological Study Using SEM, Light Microscopy, and an Image Processing System

A clinical study was conducted of 59 patients treated with 78 hydroxyapatite (HA)‐coated blade implants from August 1986. Five implants in 5 patients were broken at the neck portion, and one implant in one patient was removed from the jaw bone. The histological findings around a broken implant which was removed from the mandible are presented. These sections showed good adaptation of the bone to the implant without a fibrous layer. Histomorphometric evaluation of bone‐to‐implant contact showed 73.5%. The scanning electron microscopy image of the fractured surface revealed a fatigue fracture. The suspected cause of the fracture was stress concentration at the cervix portion, because of excessive mobility or deleterious change of abutment teeth. Consequently, the osseointegration/biointegration implants should not be connected with natural teeth. J Periodontol 1996;67:86–92 .