To determine differences in failure rate and hearing outcomes of a completely encircling heat-activated crimping prosthesis (SMart 360°) compared to partially encircling prosthesis (SMart). Retrospective chart review. Private neurotology tertiary referral center. Patients who underwent stapedotomies performed by the senior authors from 2008 to 2019 using the SMart prosthesis and SMart 360° prothesis. Stapedotomy operations with placement of a SMart or SMart 360° prosthesis. Incidence of early failure requiring revision surgery. Differences in preoperative air-bone gap (ABG) compared to postoperative ABG at 3 months, 1 year, and 2 years after surgery. A total of 228 stapedotomies were performed (SMart n = 48 and SMart 360° n = 180). Mean preoperative ABG for SMart and SMart 360° were 26.15 and 29 dB, respectively. The mean difference in ABG for the SMart at 3 months, 1 year, and 2 years were 17, 18, and 11 dB, respectively. The mean difference in ABG for the SMart 360° at 3 months, 1 year, and 2 years were 20, 20, and 19 dB. ABG differences at 3 months (p = 0.10) and 1 year (p = 0.36) were not statistically different. The failure rate for the SMart prosthesis was 12.5% and for the SMart 360° 2.2% (p = 0.002). There were no statistically significant differences in ABG changes for SMart compared to SMart 360°. The Smart 360 corrects the problem with early failure seen with the Smart prosthesis. Determination of most efficacious stapes prosthesis. Which stapes prosthesis produces better hearing results with fewer failures. To disseminate information necessary to choose the best stapes prosthesis for patients. Level III. 2022-029-agh.