and 5. Images of electron microscopic scans of experimental titanium implants. Figure 4. (a) Implant with machined surface (magnification ×27). A clear direction of grooves and ridges remains from the machining process. (b) Top of machined thread with irregular deep grooves and ridges (magnification ×2000). (c) Machined thread with less distinct ridges and grooves (magnification ×2000). (d) Valley and flank of machined thread with distinctive ridges and grooves (magnification ×2000). Figure 5. (a) Implant with acid-etched surface (magnification ×27). Regular distribution of surface texture. (b) Top of acid-etched thread with micropits of 1 to 10 μm, large elements of approximately 30 μm, and peaks of different size (magnification ×2000). (c) Acid-etched valley with micropits of 1 to 20 μm and small peaks (magnification ×2000). (d) Acid-etched flank with clearly expressed micropits of 1 to 10 μm, large elements of approximately 30 μm, and peaks of different size (magnification ×2000).