Dingxiang Yuan^*; Xin Wang; Dan Wu; Shuyan Zhang

Dental School, Capital Medical University, Beijing, China

Background: Gingival recession and marginal bone resorption after the immediate implant placement were reported frequently in aesthetic zone. Some previous studies have suggested that the recession and resorption might be due to the dis/re-connection of temporary abutment at the stage of the final restoration procedure. The customized definite abutment was expected to eliminate the gingival recession and marginal bone resorption without breaking down the seal in between abutment and gingiva around.

Aim/Hypothesis: The aim of this experiment is to measure and analyze 3-dimensional changes on facial bone and facial soft tissue around the implant based on CBCT and oral scan data after immediate implant placement and provisionalization with customized definite abutment.

Material and Methods: 21 implants were immediately installed after the teeth extraction. The customized definite abutments and provisionals were designed and fabricated by using the CAD/CAM technique and immediately connected into the implants. CBCT scans and intraoral scans were taken immediately after surgery (T₀) and 1 year after (T₁). For facial bone measurements, CBCT scans were standardized at T₀ and T₁ individually. Vertical facial bone height (VBH) and Horizontal facial bone thickness (HBT) at 0, -1, -2, -3, -5, -7, -10 mm to the implant platform was measured. For facial soft tissue measurements, CBCT scan data and intraoral scan data were merged with same time point. Gingival height (GH) and Horizontal Facial Contour Thickness (HCT) at 3, 2, 1, 0, -1, -2, -3 mm to the implant platform were measured as well. Measurements were recorded and dynamic changes within 1 year were evaluated and analyzed.

Results: Within 1 year, no failure implant was observed. 21 implants were evaluated and analyzed through CBCT and intraoral scan. At T₁, the mean HBT changes ranged from –0.94 mm to –0.40 mm at the seven different levels evaluated. The mean VBH change was –0.41 mm during the one year observation. The mean HCT changes ranged from –0.72 mm to –0.23 mm at the seven levels evaluated and statistically significant differences were observed from -3 mm to 2 mm levels. Fortunately, no statistically significant differences were observed at 3 mm coronal to the implant platform which represented the contour at gingival margin level was well maintained. The mean GH change was –0.51 mm within one year in all implants.

Conclusion and Clinical implications: Immediate implant placement and provisionalization with customized definite abutment in maxillary anterior region might be predictable within 1 year observation. The reduction of vertical bone height, horizontal bone thickness and gingival height were within an acceptable range. The soft tissue contour at gingival margin level could be well maintained. The horizontal facial contour was slightly reduced and connective tissue grafting needs to be considered to compensate the collapses.

Disclosure of Interest: None Declared

Keywords: abutment, immediate implant placement, intraoral scanner