surface electric fields increase osteoblast adhesion through improved wettability on hydroxyapatite electret osteoblasts are susceptible to the surface characteristics of bioceramics and stimulation from outside the cells the purpose of this study was to evaluate the effects of electrical polarization on surface characteristics and osteoblastic adhesion the surface characteristics revealed that electrical polarization had no effect on the surface roughness crystallinity and constituent elements according to contactangle measurements electrically polarized hydroxyapatite ha which provides two kinds of surfaces negatively charged ha nha and positively charged ha pha was even more hydrophilic than that of normal ha oha morphological observations and quantitative analyses revealed that the typical adhered cells had a round shape on oha but had a spindle or fanlike spreading configuration on nha and pha 1 h after seeding after 3 h of cultivation the rate of the number of spread cells and the size of the focal adhesions on oha increased and approached that of nha and pha however the cell areas positively stained for actin which indicates the degree of cell spreading were distinctly larger on nha and pha than that on oha the number of focal adhesions per cell was also less than that on nha and pha