Maxilla vs mandible: why use HA?

Various studies have shown that noncoated, metallic screw-type implants have been highly successful in types 1, 2, and 3 bone. However, in type 4 bone, such as that found in the maxilla, these implants have not been as successful. In the maxilla, HA-coated implants have shown better results than noncoated implants, particularly with regard to bone-to-implant contact, shear strength, and fixation. The author therefore concludes that the HA-coated implant may have better long-term success when shorter implants are needed, and when treating patients with poor, low density, and cancellous bone.