Early loading of 6-mm-short implants with a moderately rough surface supporting single crowns--a prospective 5-year cohort study

AIM: To evaluate prospectively the clinical and radiographic outcomes after 5 years of early loading of 6-mm implants with a moderately rough (SLActive(®) ) surface supporting single crowns in the posterior regions. MATERIAL AND METHODS: Thirty-five consecutive patients received 40 SLActive(®) (Straumann) 6-mm implants with a diameter of 4.1 mm (n = 19) or 4.8 mm (n = 21). Insertion torque and resonance frequency analysis (RFA) were measured at implant installation. RFA was also measured at abutment connection. SynOcta abutments were tightened with 35 Ncm after 6 weeks of healing, and single porcelain fuse to metal crowns was cemented within 1 week. Implant survival rate and marginal bone loss were evaluated at various time intervals until 5 years after loading. The clinical crown/implant ratio was calculated as well. RESULTS: Two of 40 implants were lost before loading (incorporation rate 95%), and no further implant loss or technical complications were encountered during the 5-year follow-up period. A mean marginal bone loss of 0.7 ± 0.6 mm was found after 5 years of function. The clinical crown/implant ratio increased with time from 1.6 at the delivery of the prosthesis to 2 after 5 years of loading. CONCLUSION: Six millimeter implants with a SLActive(®) moderately rough surface supporting single crowns in the posterior region and loaded after 6-7 weeks maintained full function for at least 5 year with low marginal bone resorption.