Implant component fracture in bone level implants

B8CID ePOSTER CLINICAL RESEARCH – PROSTHETICS

Background: The bone level implant systems have gained general acceptance in edentulous restorations. Despite of the satisfactory clinical performance, the implant component fracture is occurring. It is a challenging and laborious complication for dentists to tackle with. From the patients’ point of view, it is also time-consuming and effort-consuming.

Aim/Hypothesis: The aim of this study is to post clinical suggestion for the management of implant component fracture and to provide technical advice for implant design through a series of implant component fracture took place in 2 bone level implant systems over a function period varying from 1 year to 8 years.

Materials and Methods: 11 253 Straumann^® bone level implants and 2702 Ankylos^® implants between January 2012 and December 2018 were enrolled in this work. All the implant component fracture cases, that is, screw fracture, abutment fracture and implant fracture, were registered. In case of abutment-screw fracture, effort was devoted to dislodge the fractured fragment by means of manual instruments, followed by the retrieval tool and eventually with help of ultrasonic oscillations. In the case of irretrievable fractured component and implant fracture, the involved implants were surgically removed and simultaneously placed new one or GBR for re-implant six months late. The discrepancy of the fracture behavior in the two implant systems was recorded and analyzed, in terms of fracture incidence, patient-related factors, implant design and the corresponding treatment.

Results: 13 patients with 15 Straumann^® implants were confirmed as fracture while 16 patients with 16 Ankylos^® implants suffer the fragmentation. The mean fracture time located in 45.5 months. In terms of Straumann^®, 13 (0.115%) abutments fractured in coincide with screws and 2 (0.018%) fracture located in the fixture neck. All broken abutment and screws were retrieved and underwent re-restoration with no effort. With respect to Ankylos^®, 11 (0.407%) fracture located in the prosthetic component around the implant level, 8 of which were retrieved. The other 3 irretrievable prosthetic component and 5 (0.185%) fractured implant were surgically removed.

Conclusions and Clinical Implications: The implant component fracture in bone level implants is rare. The relatively higher occurrence rate of implant fracture in Ankylos^® is assumed to be ascribed to the small diameter of implant. In comparison to Straumann^®, the retrieval rate of fractured component in Ankylos^® is lower and 2 irretrievable fragments induced implant failure. This phenomeNO is presumably attributed to the clamp force of Ankylos^® exerted by smaller Morse Taper angle and larger conical contact surface.

Acknowledgements: The authors declare no conflicts of interest.

Keywords: Abutment fracture, Oral implantology, Conical contact surface