[Clinical classification and treatment decision of implant fracture]

To propose a set of two-dimensional clinical classification of fractured implants based on the follow-up of fracturing pattern of implant body and peri-implant bone defect morphology of 32 fractrued implants, and summarize the treatment decisions of fractured implants according to this new set of classification, so as to provide guidance for clinical practice.

During 25 years of clinical practice, clinical records of 27 patients of 32 fractured implants in 5 481 patients with 10 642 implants were made. The fracturing pattern of implant body, implant design, peri-implant bone defect morphology and treatment options were analyzed. A set of two-dimensional clinical classification based on the morphology and bone absorption of implant fracture was proposed. The treatment decision-making scheme based on the new classification of implant fracture was discussed.

In the new classification system, vertical fracture of implant neck (Type 1 of implant fracture morphology, F1) and horizontal fracture of implant neck (Type 2 of implant fracture morphology, F2) were common, accounting for 50% and 40.6% respectively, while deep horizontal fracture of implant body (Type 3 of implant fracture morphology, F3) (9.4%) were rare, while the three types of bone defects (D1, no bone defect or narrow infrabony defects; D2, wide 4-wall bone defects or cup-like defects, D3, wide 3-wall or 2-wall defects) around implants were evenly distributed. In the two-dimensional classification system of implant fracture, F1D1 (31.3%) and F2D2 (25%) were the most frequent. There was a significant positive correlation between F1 and D1 (r=0.592, P < 0.001), a significant positive correlation between F2 and D2 (r=0.352, P=0.048), and a significant negative correlation between F1 and D2 (r=-0.465, P=0.007). The most common treatment for implant fracture was implant removal + guided bone regeneration(GBR) + delayed implant (65.6%), followed by implant removal + simultaneous implant (18.8%). F1D1 type was significantly related to the treatment strategy of implant removal + simultaneous implantation (r=0.367, P=0.039). On this basis, the decision tree of implant fracture treatment was summarized.

The new two-dimensional classification of implant fracture is suitable for clinical application, and can provide guidance and reference for clinical treatment of implant fracture.