BONE RESPONSE TO UNLOADED AND LOADED TITANIUM IMPLANTS WITH A SANDBLASTED AND ACID-ETCHED SURFACE - A HISTOMETRIC STUDY IN THE CANINE MANDIBLE

Many dental clinical implant studies have focused on the success of en dosseous implants with a variety of surface characteristics. Most of t he surface alterations have been aimed at achieving greater bone-to-im plant contact as determined histometrically at the light microscopic l evel. A previous investigation in non-oral bone under shortterm healin g periods (3 and 6 weeks) indicated that a sandblasted and acid-etched titanium (SLA) implant had a greater bone-to-implant contact than did a comparably-shaped implant with a titanium plasma-sprayed (TPS) surf ace. In this canine mandible study, nonsubmerged implants with a SLA s urface were compared to TPS-coated implants under loaded and nonloaded conditions for up to 15 months. Six foxhound dogs had 69 implants pla ced in an alternating pattern with six implants placed bilaterally in each dog. Gold crowns that mimicked the natural occlusion were fabrica ted for four dogs. Histometric analysis of bone contact with the impla nts was made for two dogs after 3 months of healing (unloaded group), 6 months of healing (3 months loaded), and after 15 months of healing (12 months loaded). The SLA implants had a significantly higher (p < 0 .001) percentage of bone-to-implant contact than did the TPS implants after 3 months of healing (72.33 +/- 7.16 versus 52.15 +/- 9.19; mean +/- SD). After 3 months of loading (6 months of healing) no significan t difference was found between the SLA and TPS surfaced implants (68.2 1 +/- 10.44 and 78.18 +/- 6.81, respectively). After 12 months of load ing (15 months of healing) the SLA implants had a significantly greate r percentage (p < 0.001) of bone-to-implant contact than did the TPS i mplants (71.68 +/- 6.64 and 58.88 +/- 4.62, respectively). No qualitat ive differences in bone tissue were observed between the two groups of implants nor was there any difference between the implants at the cli nical level. These results are consistent with earlier studies on SLA implants and suggest that this surface promotes greater osseous contac t at earlier time points compared to TPS-coated implants. (C) 1998 Joh n Wiley & Sons, Inc.