Tehran University of Medical Sciences Frontiers in Dentistry 2676-296X 8 4 2011 12 15 186 200 AR. Rokn Associate Professor, Department of Periodontics, School of Dentistry, Tehran University of Medical S AAR. Rasouli Ghahroudi 3Assistant Professor, Dental Research Center, Tehran University of Medical Sciences, Tehran, Iran A. Mesgarzadeh Associate Professor, Department of Oral and Maxillofacial Surgery, School of Dentistry, Tehran Unive AA. Miremadi Associate Professor, Department of Periodontics, School of Dentistry, Tehran University of Medical S S. Yaghoobi Assistant Professor, Dental Research Center, Tehran University of Medical Sciences, Tehran, Iran 2015 10 03 Objective: To determine the pattern of stability changes as a reflection of early healing around single-stage roughened-surface implants in humans utilizing resonance frequency analysis (RFA). Materials and Methods: Hundred twenty-five patients who demanded dental implants were treated with two different implant (Nobel Biocare ReplaceTM and StrummanTM ITI) systems. Bone type was classified into four groups. RFA was used for direct measurement of implant stability on the day of implant placement and consecutively at 14, 30 and 60 days after placement. The data were analyzed with Student t test and regression analysis. Results: Three-hundred four roughened surface implants placed in the maxilla and mandible were evaluated. In ReplaceTM implants the lowest mean stability measurement was at 30 days for all bone types and the stability did not change significantly in any of the bone types (p>0.05). ITITM implants demonstrated the lowest stability at 60 days for type 1 and 30 days and baseline for type 2, 3 and 4 bones. In addition, there was significant differences in implant stability between bone types 1 and 4 (P<0.001), 2 and 3 (p<0.05) , and bone types 3 and 4 (P=0.07) at all aforementioned times in ITITM implants. In ReplaceTM implants, regarding the implant diameter, contrary to ITI implants, no significant stability changes were detected (p>0.05). No significant difference was observed regarding gender, age and lengths in both systems. Conclusion: In comparison to ITITM implants, ReplaceTM implants revealed no significant difference in the pattern of stability changes among different bone types. https://fid.tums.ac.ir/index.php/fid/article/view/262 https://fid.tums.ac.ir/index.php/fid/article/download/262/262