Fig. (3) When measuring sliding distance, corrections were made using the ratio of screw length (L1) measured on the radiograph to actual screw length (L). The distance from the tip of the screw to the implant as measured on the radiograph was recorded as L2. The corrected distance from the tip of the screw to the implant was calculated using the following equation: L2 × (L / L1). The difference between corrected distance at final observation and corrected distance immediately after surgery was calculated as the sliding distance. The distance from the tip of the screw to the barrel was measured.