Randomized multicenter comparison of two coatings of intramobile cylinder implants in 313 partially edentulous mandibles followed up for 5 years.

Intramobile cylinder (IMZ) implants with either of two coatings, hydroxyapatite (HA) or titanium plasma-flame (TPF), as distal abutments for combined tooth implant-supported restorations, were compared in 313 partially edentulous mandibles with respect to postprosthetical failure patterns and complication frequencies in a randomized multicenter clinical trial. Within the treatment protocols, the two coatings do not show evidence of different efficacy with respect to occurrence of postprosthetical integration deficiency (ID) or functional deficiency (FD). Statistical equivalence for an absolute effect of +/-15% in event-free survival could only be demonstrated for FD, not for ID, however. Intent-to-treat and per-protocol population analyses gave consistent results. Hazards of occurrence of ID and FD, adjusted for years of follow-up, were estimated for ID as 7% per year (95%CI 4-10% per year) with HA and 5% per year (95%CI 3-7% per year) with TPF, and for FD as 5% per year (95%CI 3-7% per year) with HA and 4% per year (95%CI 2-6% per year) with TPF. The 5-year cumulative success rates for no ID were 69.5% (95%CI 58-81%) with HA and 82.2% (95%CI 74-91%) with TPF. With respect to frequencies of complications, there was no relevant statistically significant difference between the two coatings.