Factors Affecting Implant Mobility at Placement and Integration of Mobile Implants at Uncovering

T his study examined 1) factors that contributed to implant stability at placement and 2) the likelihood for an implant that was mobile at placement to osseointegrate. Eighty‐one (3.1%) of 2,641 implants placed by the Dental Implant Clinical Research Group between 1991 and 1995 were found to be mobile at placement. Seventy‐six (93.8%) of the 81 mobile implants were integrated at uncovering compared to 97.5% for the 2,560 immobile implants. Variables that influenced mobility at placement included patient age, implant design and material, anterior‐posterior jaw location, bone density, and use of a bone tap. Hydroxyapatite (HA)‐coated implants were slightly more likely to be mobile at placement ( P = 0.324) than non‐hydroxypatite (HA)coated implants. Of the 54 HA‐coated implants that were mobile at placement, all (100%) integrated, while only 17 (81.5%) of the 22 mobile non‐HA‐coated implants integrated ( P = 0.003). Mean electronic mobility testing device values (PTVs) at uncovering for all implants mobile or immobile at placement that integrated were −2.9 and −3.6 respectively. PTVs for HA‐coated implants that were mobile (−3.5 PTV) or immobile (−4.0 PTV) at placement differed by 0.5 PTV, whereas non‐HA‐coated implants exhibited a greater difference of 1.2 PTVs at uncovering. HA‐coated implants, regardless of mobility at placement, integrated more frequently and exhibited greater stability than non HA‐coated implants. J Periodontol 1998;69:1404–1412 .