Objectives <p>The aim of this randomized clinical trial was to clinically and radiographically compare the effect of osseodensification (OD) and conventional drilling (CD) on implant stability in the posterior maxilla.</p> Materials and methods <p>Twenty patients received 20 implants after being randomly assigned for osteotomy preparation with either OD (test) (<i>n</i> = 10) or CD (control) (<i>n</i> = 10). Implant stability quotient (ISQ) and crestal bone loss were monitored closely from implant insertion through 12 months of loading. Insertion torque and implant survival were also assessed during the study.</p> Results <p>In OD group, one patient was lost to follow up and all other implants were in Function after 12 months of loading (9/9), while only 8/10 implants survived in CD group. OD was associated with significantly higher mean ISQ values; post-insertion and during the 1st month of healing, compared to CD. A high relatively unchanged stability was observed throughout osseointegration with OD method, while a stability dip occurred during the 2nd and 3rd weeks of healing in CD group. There was no significant difference in crestal bone loss and insertion torque between groups.</p> Conclusions <p>Within the limitations of this study, OD seems to provide earlier implant stability in terms of ISQ values, and may improve survival rates in the posterior maxilla, compared to CD, with no negative impact on crestal bone after 12 months of implant loading. ClinicalTrials.gov Identifier: <i>NCT04442763</i> (registration date 15/6/2020).</p> Clinical relevance <p>OD may be used as an alternative to CD to achieve earlier implant stability in the posterior maxilla.</p>