and 5. Figure 4. (a) Sandblasted and acid-etched surface in graft: General overview of the SLA implant. The graft area is limited to the apical side of the peri-implant bone. The bone structure is poor with thin and brittle trabeculae (Toluidine blue, basic fuchsin, original magnification ×8). (b) Sandblasted and acid-etched surface in graft: Magnification of the previous implant is in rectangle A. A very thin layer of newly formed bone was adapted on the sandblasted and acid-etched surface, particularly at the level of the threads (Toluidine blue, basic fuchsin, original magnification ×25). (c) Sandblasted and acid-etched surface in graft: Magnification of the previous implant is in rectangle B corresponding to the sinus grafted region. The bone (B) is denser at this level and the connectivity is more pronounced. Many different-sized graft particles (G) are embedded in the newly formed bone trabeculae (M = marrow tissues, IT = implant thread) (Toluidine blue, basic fuchsin, original magnification ×25). Figure 5. (a) Hydroxyapatite (HA) surface in graft: General overview of the HA-coated implant. The graft area is spread all around the peri-implant bone. The bone structure is dense but the trabeculae are inconsistently arranged (Toluidine blue, basic fuchsin, original magnification ×8). (b) HA surface in graft: Magnification of the HA-coated implant. The coating (arrows) was clearly visible with a well-preserved structure and thickness and a high percentage of osseointegration (B = bone; G = graft particles) (Toluidine blue, basic fuchsin, original magnification ×25). (c) HA surface in graft: Magnification of the apical part of the HA-coated implant. The most apical threads were surrounded by many graft particles and a small amount of vital bone. However, the HA-coating (arrows) was layered by a continuous bony trabeculum (B = bone, G = graft particles) (Toluidine blue, basic fuchsin, original magnification ×25)