Turned, machined versus double-etched dental implants in vivo

Background: Positive effects on the clinical outcome of moderately rough implant surfaces are described. Intercomparison of clinical data, however, is rarely found. Purpose: The aim of this study was to compare the clinical results of two macroscopically identical implants, the one with a turned, machined and the other with an etched surface. Materials and Methods: In a retrospective cohort study, the included implants followed the criteria: standard surgical protocol, >12 months in situ; minimally rough self‐threading implants with a turned, machined surface (Mk II^TM Nobel Biocare AB, Göteborg, Sweden], n=210); etched implants of the same macrodesign (3i^TM Implant Innovations Inc., Palm Beach Gardens, FL, USA], n=151), length ≥ 10 mm. Clinical data and implant success were rated. Resonance frequency analysis (RFA) and Periotest® (Siemens AG, Bensheim, Germany) were measured and related to the corresponding implant survival rate in the respective group. Results: The total number of implants was 361, of which 264 (73%) were subject to clinical reexamination. RFA and Periotest could be recorded in 25% of the implants. Neither clinically relevant nor statistically significant differences between the surface designs were found in the RFA (64 ± 8.6 vs 63 ± 9.7), in Periotest (?2 ± 3.3 vs ?1 ± 5.1), and in mean survival periods (49 months, 95% confidence interval CI]: 46–51 months, for the turned vs 46 months, 95% CI: 43–49 months, for the double‐etched implant). After osteoplastic procedures, a significantly higher rate of implant losses in the turned, machined implant group was observed (17 vs 1) with a mean survival period of 43 (40–46) months for the turned and 46 (45–48) months for the double‐etched implants. Conclusion: No difference between implants with two different minimally rough surfaces was found. A positive effect of surface roughness is observed in poor quality bone, but the pivotal proof of this effect is still lacking.