After incision and flap reflection, the crest appears to be composed of the buccal and palatal plates (fusion of two layers of the cortical bone).  The crest is narrow and dense.  Bone expansion starts with using a surgical fissure bur to make a slot between the buccal and lingual plates, followed by bone scalpels and bone blades.  The bone is dense; bone expansion extends ~ 9 mm.  A 1.6 mm pilot drill is used at the depth of 14 mm, followed by 2.6, 3.0 and 3.4 mm bone expanders.  Both the buccal and lingual plates are expanded.  When a 4.5 mm tap is inserted (Fig.1,2 T), the buccal plate is shown to be bulging and breaking down (Fig.1 *).

Dense Bone Last Next Xin Wei, DDS, PhD, MS 1st edition 01/17/2016, last revision 01/19/2019