Volume of unsupported peri-implant soft tissue over time: A cross-sectional observation study

Supraimplant emergence profile changes have revealed that, when not supported, peri-implant soft tissue collapses. However, this phenomenon has not been described qualitatively and quantitatively in 3 dimensions.

The purpose of this cross-sectional clinical study was to analyze changes in the supraimplant emergence profile digitally over time when the peri-implant soft tissue was not supported.

A data set consisting of 16 participants with 16 implants was used. After removal of the healing abutment or the interim restoration, 4 intraoral optical impressions were made successively on the patient to record the supraimplant emergence profile at 4 different times: 0 second (T₀), 30 seconds (T_{0.5 min}), 2 minutes (T_{2 min}), and 5 minutes (T_{5 min}). The supraimplant emergence profile surfaces obtained were closed with a 3D meshing software program (Meshmixer) to obtain the volume of the supraimplant emergence profile at each time. The reference volume at T₀ (Vol T₀) corresponded to the volume created during the mucosal healing phase, which, theoretically, should be preserved for the fabrication of the definitive crown. The different volumes (Vol T_{0.5 min}, Vol T_{2 min}, and Vol T_{5 min}) were compared with Vol T₀ to analyze the volumetric changes, kinetics, and topography of this variation by using a 3D visualization and analysis software program (Avizo). A nonparametric Wilcoxon test for paired samples was used for comparison.

The supraimplant emergence profile volume decreased by an average of 5% at 30 seconds (P<.001), 10% at 2 minutes (P<.001), and 14% at 5 minutes (P<.001).

The supraimplant emergence profile collapsed significantly in 3D when unsupported for 30 seconds or more.