TISSUE-REACTIONS TO VARIOUS PERCUTANEOUS MATERIALS WITH DIFFERENT SURFACE-PROPERTIES AND STRUCTURES

Tissue responses to various percutaneous materials with different surf ace properties and structures were investigated. Dense hydroxyapatite (HA), tricalcium phosphate (TCP), glassy carbon (GC), and 2 types of p orous HA were used. Cutaneous and subcutaneous tissues were tightly at tached to the surface of the penetrating portion of an HA percutaneous device (PD). Neither bacterial infection nor serious epidermal downgr owth were observed in the area surrounding the shaft of the HA-PD. At the margin of the epidermis, fibroblasts and collagen fibrils of fibro us connective tissue were well oriented and formed perpendicular to th e shaft. The tissue response to the TCP was mild and nearly the same a s that to the HA. The GC induced serious epidermal downgrowth and infl ammatory cell infiltration. In contrast to dense HA-PD, the insertion of both types of porous HA-PDs, 1 with a spongy structure and 1 with c lose pores was followed by acute infection within 1 month. Based upon these results, it was concluded that the dense HA was the best percuta neous material of those tested.