Supracrestal Tissue Height Changes Around the Healing Abutment in the Posterior Region after Second-Stage Implant Surgery Measured by Intraoral Scanning: A Retrospective Study

OBJECTIVES:The study aimed to explore the changes in the height of the soft tissue around the healing abutment at different time points after second-stage implant surgery. METHODS:Cone-beam computed tomography (CBCT) data were collected at baseline (second-stage surgery), and intraoral scans were obtained at baseline and multiple follow-up visits: after suture removal (1 week post-surgery), during impression taking, and immediately before performing restoration. Patients were grouped based on the time of impression taking (1 or 2 weeks post-suture removal: 1I or 2I), and further subgrouped according to the timing of performing restoration (2, 3, or 4 weeks post-impression: 2R, 3R, or 4R). Digital datasets were superimposed using tooth-supported reference areas before the intraoral height of the healing abutment and the supracrestal tissue height (STH) were measured at the mesial, distal, buccal, and lingual sites at the different time periods. RESULTS:A total of 76 patients with 102 implants were enrolled in the study; specifically, 22 were in the 1I2R group, 18 in 1I3R, 14 in 1I4R, 14 in 2I2R, 18 in 2I3R, and 16 in 2I4R. The STH changes of 2I3R group were (0.37 ± 0.13), (0.41 ± 0.21), (0.43 ± 0.17), (0.43 ± 0.20) mm at the mesial, distal, buccal, and lingual sites, which showed no statistically significant differences with 2I4R group whose STH changes were (0.35 ± 0.13), (0.43 ± 0.22), (0.39 ± 0.16), (0.41 ± 0.14) mm, respectively. the changes of these two groups were Larger Than Other groups, with significant differences (p < 0.01). CONCLUSIONS:Within the study limits, STH around healing abutment tended to stabilize approximately 6 weeks after second-stage surgery.