Evaluating stability changes of tapered roughened surface implants in different bone types and fast loading: a prospective clinical cohort study

Background and aims. Implant stability of different designs have shown to be variable. The aim of this study was to evaluate the stability changes as a reflection of early healing around roughened-surface implants in human using resonance frequency analysis (RFA). Materials and methods. 153 Branemark Replace tapered Ti-uniteTM implants in 68 patients were placed in the maxilla or mandible. Bone type was classified into one of 4 groups according to Lekholm and Zarb index. RFA was used for direct implant stability measurement on the day of implant placement and at 14, 30 and 60 days after placement. Results. No early failure occurred. The lowest primary stability measurement was observed in type 4 bone. Student t-test for comparison of bone groups at each time point revealed no significant difference between implant stability in all bone types (P > 0.05). In testing the effect of implant length and diameter with time using the mixed model ANOVA according to implant length, there was not any significant difference between groups (P > 0.05); however, implant diameter showed a significant effect on implant stability. There were no significant differences in implant stability between genders (P > 0.05). Conclusion. According to the results, pattern of stability changes are not different among different bone types.