Three-Dimensional Evaluation of Peri-implant Soft Tissue When Tapered Implants Are Placed: Pilot Study with Implants Placed Immediately or Early Following Tooth Extraction

Purpose: This study examined a new 3D volumetric analysis method for the assessment of baseline-to-12-month changes of the soft tissue volume at early and immediately placed tapered implants after loading with ceramic single crowns. Materials and Methods: Eligible patients with one incisor, canine, or premolar to be extracted were included. The patients were divided randomly into early-placement or immediate-placement groups. Tapered implants (BLT, Institut Straumann) were placed after the extractions. In the early-placement group, the implants were placed 8 weeks after extraction. In the immediate-placement group, the implants were placed immediately after the extraction. All implants healed transmucosally, and the final crowns were inserted after healing (baseline). Impressions were made at screening, baseline, and 12 months after crown insertion (Permadyne, 3M). The casts were scanned (Imetric 4D) and aligned, and a superimposed area of interest (AOI) (labial/buccal aspects) was defined to assess the volumetric changes (GOM Inspect). Specific software (3Matic, Materialise NV) was used for volumetric analysis. The vertical mucosal recession was measured at each time point. Repeated-measures one-way analysis of variance and the Tukey method were used for statistical analysis (SPSS 22, IBM). Results: Twenty tapered implants (16 regular and four narrow) were placed in 20 patients (12 men and 8 women) in the early-placement (EP; n = 10) and immediate-placement (IP; n = 10) groups, respectively. Threedimensional volumetric analysis revealed soft tissue volume loss in both groups of 10.0 ± 16.5 mm3 (EP) and 24.3 ± 21.3 mm3 (IP) between baseline and 12 months (P = .6). The analysis also revealed local differences in the changes, displaying both localized gain and loss in both groups. Conclusion: With this novel 3D analysis method, true volumetric soft tissue differences, ie, both localized gain and loss, were specified between the treatment groups. Keywords: dental implants, early placement, immediate placement, soft tissue changes, volumetric analysis