This prospective controlled clinical trial investigated the possible correlation among mucosa thickness, mucosa height, and width of keratinized mucosa on the contour changes of the peri-implant soft tissue collar over a period of 12 months. Forty patients were selected to undergo implant placement. Impressions were taken with polyether impression material at delivery of the final restorations (baseline) and at 1, 3, 6, and 12 months. Master casts were fabricated and scanned using an indirect digitalization. Baseline and corresponding follow-up scans were then virtually superimposed and matched. At 1 year, 20 patients who received the buccal pedicle flap showed an average thickness increase of 1.49 mm (ρs = 0.95; range: 0.01 to 2.56 mm), whereas the 5 patients who received a connective tissue graft at second-stage surgery reported an average thickness increase of 0.33 mm (ρs = 0.70; range: –0.62 to 1.23 mm). Finally, the remaining 15 patients who did not receive any soft tissue grafting nor any type of plastic surgery showed an average mucosa thickness increase of 0.51 mm (ρs = 0.28; range: –2.33 to 2.52 mm).
