Mechanical complication is one of unavoidable problems in the implant restorations, and of that, components fracture makes
catastrophic results affecting implant longevity. Especially, internal connection implant has weaker point in the implant
platform-abutment junction when compared to external connection implant. However, mid-, long-term clinical result of internal
connection implant components fracture has not been known well.

The aim of this study was to investigate the components fracture of internal connection implant in the posterior partially edentulous
patient, and to suppose the reason of failure.

Implants inserted in the posterior region between February 2004 to August 2012 and loaded at least 5 years or more at Seoul
National University Bundang Hospital, Section of Dentistry were subjected in this study. Fractured implant restorations for premolar
and molar were analyzed according to sex, age, diameter, length, location, loading time until fracture, crown to implant ratio (C/I ratio),
bone loss, multiple splinted or single and occlusion. Chi-square test, Kaplan Meier and Log-rank test, and Wilcoxon signed rank test
were performed at a significance level of P< .05.

A total of 1817 implants placed in 768 patients were included. Forty nine implants of components fractures in 34 patients occurred
and five of patients made repeated fractures. Fracture rate was 2.70% in implant numbers and loading time until fracture was mean
69.09±30.09 months. Most frequent location was abutment hex. Combined fractures of abutment hex and abutment screw were
followed. There were significant differences in sex, implant location and restored implant numbers (P< .05). Fracture occurred more
frequently in men, molar regions, and a single restoration. However, arch location, C/I ratio, and bone loss were not related with
components fracture.

Within the limits of complex restoration situation, 5 years or more mid-, long-term clinical results showed that restoration of internal
connection implant in single molar crown for men should be under meticulous follow up to avoid mechanical complication.
Components fracture was related with high occlusal force. Repeated fractures in some patients were considerable factors to be
noticeable.

Clinical study of implant components fracture in posterior partially edentulous restorative patient