In Western European countries an All-on-Four restoration typically costs £12,900 to £21,500 per jaw and £25,800 to £38,700 for both. In Istanbul, All-on-Four packages (premium implants, definitive bridge, all pre-op tests, hotel, transfer, both trips) are offered at significantly lower prices. The implants themselves (Straumann, Nobel Biocare etc.) are delivered to the same global standard. What you should check: whether the premium brand or a cheaper variant is used; whether the definitive bridge is zirconia or acrylic-hybrid; what the second trip costs; what the warranty covers. Ask for a written breakdown.