Removal Torque Values of Titanium Implants in the Maxilla of Miniature Pigs
Daniel Buser, DDS, Thomas Nydegger, Hans Peter Hirt, DDS, David L. Cochran, DDS, PhD, , Lutz-Peter Nolte, PhD.
The purpose of this study was to compare side-by-side two different titanium screw-type implants in the maxillae of miniature pigs. The test implants had a machined and acid-etched surface (Osseotite) whereas the control implants were sandblasted and acid-etched (SLA). After 4, 8, and 12 weeks of healing, removal torque testing was performed to evaluate the shear strength of the bone-implant interface for both implant types. The results demonstrated significant differences between both implant types (P < .01). Osseotite implants revealed mean removal torque values (RTV) of 62.5 Ncm at 4 weeks, 87.6 Ncm at 8 weeks, and 95.7 Ncm at 12 weeks of healing. In contrast, the SLA implants demonstrated mean RTV of 109.6 Ncm, 196.7 Ncm, and 186.8 Ncm at corresponding healing periods. The mean RTV for SLA implants was 75% to 125% higher than for Osseotite implants up to 3 months of healing. (INT J ORAL MAXILLOFAC IMPLANTS 1998;13:611-619) Key words: interface shear strength, removal torque values, Osseotite surface, sandblasted and acid-etched surface, SLA surface, titanium implants