A hair treatment or styling apparatus adapted to impart a straightening and/or curling effect on hair includes both a novel thermally conductive construction and heating assembly, which conveys thermal energy uniformly to all areas of the treatment head such that the desired style is achieved regardless of the skill of the user. The apparatus further includes a hinge assembly incorporating one or more ceramic bearings units which provide smooth consistent resistance for pivoting movement of the treatment members and a more durable hinge joint thereby increasing the life and usability of the apparatus.