Importance of ground section thickness for reliable histomorphometrical results

Ten screw-shaped commercially pure titanium implants were inserted in 10 rabbit tibia. The implants with surrounding bone were harvested after 12 weeks. The samples were processed to be cut and ground. Histomorphometrical analyses of the bone-to-metal contact and the bone area around the entire implants were performed on transvertically cut sections at intervals, starting with 100 microns thick sections; then the same sections were further ground down to 50, 30 and 10 microns. The thicker the section the more bone-to-metal contacts were demonstrated. A statistically significant difference was obtained when comparing the 100-30, 100-10, 50-30 and the 50-10 microns thick sections. Comparing the area measurements of 100-10, 50-30, 50-10 and 30-10 microns revealed a statistically significant difference. Bone-to-metal contact measurements on ground sections that are too thick (over 30 microns) may result in overestimations of the 'true' bony contacts.