Three-dimensional evaluation of soft tissue changes following placement of two different healing abutments with different emergence profile designs: A randomized controlled trial.

PURPOSE: The purpose of this trial was to assess linear dimensional and volumetric changes of buccal peri-implant soft tissues of mandibular single first molar implants after 3 months of healing using a prefabricated scannable healing abutment (HA) with a convex emergence profile (EP) in comparison with a customized non-scannable HA with a concave EP. MATERIALS AND METHODS: Twenty-four subjects were included in the trial. Single implants were placed in mandibular first molars. Two groups of participants were assigned at random to either a control group that received a custom HA with a concave EP (n = 12) or a test group that received a prefabricated scannable HA with a convex EP (n = 12) on the day of implant placement. Pre- and 3-month intraoral scans were made to measure linear dimensional and volumetric changes of buccal peri-implant soft tissues using a three-dimensional metrology software program. Statistical analysis was performed using Mann-Whitney U test and independent sample t-test for linear dimensional and volumetric changes, respectively (α = 0.05). RESULTS: A statistically significant difference was found regarding the linear dimensional changes between test and control groups at 0 and 1 mm from soft tissue margin around the HA (p = 0.001 and 0.005, respectively), with slightly higher values for the control group. No statistically significant difference was shown between the tested groups at 2, 3, and 4 mm from the soft tissue margin (p = 0.419, 0.073, and 0.908, respectively). Moreover, there was not a statistically significant difference in the digital analysis of volumetric changes between the two groups (p = 0.062). CONCLUSIONS: Scannable HAs with convex EP design showed comparable results to customized HAs with concave EP design regarding the buccal soft tissue volume in mandibular first molar implant sites. Although statistically significant differences were found, this was likely of very limited clinical significance.