This study proposed a protocol of prognostic evaluation system for the purpose of improving the quality of implant technology. Cases were divided into tumor and non-tumor cases according to the criteria proposed by Katagiri (2002). The biopsy factor / five items (B1 to B5) shown below were extracted, and each item was scored on a four-point scale (0 to 3) and evaluated. B1: Presence or absence of peri-implant inflammation (nonspecific reaction), and the severity B2: Presence or absence of

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... ic reactions suspected of severe infection or allergy, and the severity B3: Presence or absence of involvement of peri-implant epithelium, and the severity B4: Presence or absence of bone resorption and destruction, and the severity B5: Presence or absence of implant instability, and the severity [however, the key point for a clinically stable state is evaluated by whether bony encapsulation dominates over fibrous encapsulation] Considering the cost-effectiveness in the choice of staining methods necessary for evaluation, HE staining and Azan staining are effective for studying general morphology, PAS reaction and Grocott staining for demonstrating fungi and general bacteria, and immunostainig (AE1/AE3) for confirming epithelial or immune cells.