Resistência à fratura por flexão de tíbias de coelho hígidas e transfixadas por implantes osseointegráveis / Fracture resistance of tibiae rabbits transfixed by osseointegrated screw implants

RESUMO

The aim of the present study was to verify the fracture resistance of tibiae of 20 rabbits (New Zealand type) transfixed by osseointegrated screw implants (measuring 3.75mm in diameter and 10mm in length), by means of a 3-point bending test, immediately after implant placement or after a 6-month period of osseointegration, utilizing the homologous intact tibia as the control. An implant was placed in one tibia of each of the 10 animals in the first group, osseointegrated (OG), at 8 months old, which was ventrally inserted 5mm distally to the anterior tuberosity, surpassing the opposite cortical layer in about 1 to 2mm; these rabbits were sacrificed after 6 months (14 months old), when their tibiae were assessed. The others ten animals in the second group, non-osseointegrated (NOG), also at 14 months old, firstly they were sacrificed, their tibiae received basically the same surgical treatment of the anterior group and immediately assessed. The mean resistance of the intact and implanted tibiae, respectively, was 66.03 and 37.06kgf for the NOG, and 54.76 and 67.99kgf for the OG. This 42.67% decrease in the first group and the 25.86% increase in the second group were statistically pointed out as significant differences. Another finding was a weakening of the intact tibiae in the OG in relation to the NOG. A correlation between these results and clinical cases involving severely atrophied human mandibles may reasonably be established