Do implant surfaces make a difference?

The synthetic biomaterials commonly used as an interface or surface for soft- and hard-tissue attachment and integration are commercially pure titanium, titanium alloy (usually Ti6A14V), and hydroxyapatite. This review attempts to address the following questions: Do the epithelium and connective tissue attach or adapt to these synthetic surfaces? Is there a seal or just a cuff in terms of the soft-tissue interface? Is hydroxyapatite, commercially pure titanium, or Ti6A14V more predictable and retentive? Is one better than the other or are all the same? Is there an advantage of one surface over the other in terms of bone-to-implant contact or shear strength when stressed? How about bone density and fixture length; is one surface better than any other?