Nine hollow dental implants that were removed from patients were examined histologically to determine whether there was a common mechanism of failure with this implant design. When a hollow implant showed saucerized bone loss at the neck portion radiologically, the hollow portion was divided histologically into soft tissue and bone tissue. In advanced cases, stratified flattened epithelium that had invaded the hollow and the dead space at the top was observed. The condition of bone tissue located in the bottom of the basket can be adversely affected by an unfavorable crown-root ratio. The presence of an empty basket may cause fracture of the basket portion. The hollow portion can foster the growth of pathogenic bacteria. The hollow-type implant may not be suitable for immediate placement because surrounding soft tissues can invade the basket immediately. Schlagwörter: dental implant, failing implant, full body implant, histology, hollow implant