Abstract
BACKGROUND: Intravenous sedation (IVS) reduces anxiety during dental implant placement, but its association with mid-term peri-implant outcomes and post-treatment maintenance engagement in routine adult patients remains unclear. This study evaluated whether IVS is associated with maintenance attendance and 3-year implant therapy outcomes. METHODS: In this single-center retrospective cohort study using electronic dental records from a dental clinic in Japan, we included medically healthy non-smoking adults (≥18 years) who underwent posterior implant placement in native bone without augmentation and had ≥3 years of follow-up after definitive superstructure delivery (July 1, 2000, to May 31, 2023). Exposure was intravenous sedation with midazolam and propofol administered by an anesthesiologist versus local anesthesia alone. The primary outcome was maintenance attendance within six months after superstructure delivery (yes/no). Secondary outcomes included three-year implant survival; peri-implant clinical parameters (plaque control record [PCR] and bleeding on probing [BOP]); radiographic buccolingual bone width and horizontal bone loss; peri-implant mucositis; additional implant placement; and patient-reported outcomes. Group comparisons used Mann-Whitney U and Fisher's exact tests (two-sided α = 0.05). RESULTS: Maintenance attendance was higher with IVS (96.8% vs. 63.0%). Three-year implant survival was 100% in both groups. BOP decreased from baseline in the IVS group; however, the between-group difference at three years did not reach statistical significance (p = 0.08). Horizontal bone loss was smaller with IVS (0.04 vs. 0.14 mm), and crestal bone width was greater with similar apical width. PCR improved in both groups. Additional implant placement was more frequent in the IVS group. Patient-reported outcomes favored IVS for relaxation, pain perception, and amnesia. CONCLUSIONS: In this retrospective cohort, IVS use was associated with higher short-term maintenance attendance and more favorable patient-reported perioperative experience. Because of baseline group differences and the observational design, clinical and radiographic findings should be interpreted as associative and hypothesis-generating. Prospective multicenter studies with longer follow-up are warranted.