Abstract
Dental implant placement is one of the modern treatments for the patients who lost their original tooth. A numerous treatment using titanium implants has been increased in the last decade. With the increase of the implant treatments, the implant failure also increases. Most of the implant failure cases result from the physical rejection or the infections, but a few cases of the mechanical fracture in the implant system are also reported. Most of the mechanical failures in the implant system are caused by the cyclic fatigue damage, but the analyses based on the mechanical viewpoints have not been reported.
In the present work, the fractography analyses were applied for the two cases of the dental implant failure. The titanium implants in the maxillofacial bone were removed from the patients, as the implant fracture was confirmed in the radiographs. The striations were clearly observed on both fracture surfaces of the removed dental implants. The cyclic stress range subjected to the dental implant was also estimated from the tooth root angles and the mastication force. The factors that induced the fatigue fracture of the titanium implant in maxillofacial bone were discussed from the viewpoints of the mechanics and the oral surgery.
