CUTTING DIRECTIONS OF BONE WITH BIOMATERIALS IN-SITU DOES INFLUENCE THE OUTCOME OF HISTOMORPHOMETRICAL QUANTIFICATIONS

Ten commercially pure titanium implants were inserted in the tibia of ten mature New Zealand white rabbits for a healing period of 3 months. Cut and ground sections were performed on transversely and longitudin ally cut tibia bone with implants in situ. Each implant with surroundi ng bone was processed by (a) dividing it into two parts by cutting tra nsversely through the tibia and then (b) cutting one of the implant ha lves longitudinally through the tibia. In both cases 10 mu m sections were made. Computerized histomorphometrical calculations of the bone-t o-metal contact and the bone area in the threads were performed and co mparisons of the differently cut sections were made for the same impla nt. Larger amounts of bone-to-metal contact and bone area in the threa ds were observed in the longitudinally cut samples in comparison to tr ansversely cut ones. A strong statistically significant difference was obtained when comparing the transversely with the longitudinally cut samples with respect to bony contacts in the cortical region, demonstr ating 25% more bone-to-metal contact lengths in the longitudinal cutti ng direction of the tibia. Quantitative histomorphometrical comparison s should, therefore, be performed on samples that are cut in the same direction.