A prospective split-mouth comparative study of two screw-shaped self-tapping pure titanium implant systems

Clinical data indicate different medium and long-term outcomes of endosseou s implants for different implant configurations and in particular implant s urfaces. The present study compares 2 very similar implant systems but with different surface characteristics in a split-mouth-randomized design. The Astra-Tech (A) system (Astra-Tech AB, Molndal, Sweden) consisted of selftap ping TiO2-blasted screw-shaped implants made of commercially pure titanium? and the Branemark (B) System (Nobel Biocare, Gothenburg, Sweden) comprised selftapping Mark II implants with machined surface irregularities. Through out the 2-years' observation period, no significant differences could be fo und concerning probing depths, presence of plaque or change in marginal bon e level. A statistically significant difference in location of the marginal bone level in relation to the shoulder of the implant was found in favor o f the A system both at baseline and after 2 years. Cumulative success rates of 100% (A) and 97.7% (B) were not statistically different. From a prosthe tic point of view, more soldering points were needed for A compared to B to reach clinical acceptable fit. More years of observation are needed to com pare the fate of the soft and hard tissues surrounding two different implan t surfaces.