Comparison of Three Transmucosal Augmentation Techniques in Immediate Implant Placement

Successful regeneration is achieved when the combination of socket grafting and transmucosal augmentation (C-CTG or S-CTG or DZ) would be able to counteract any buccal soft tissue loss at level -1 mm. It is assessed on the basis of superimposed CBCTs taken pre-operatively and at one-year follow-up.

Horizontal buccal bone loss at level -1 mm is calculated by subtracting the pre-operative horizontal buccal bone level from the 1-year horizontal buccal bone level, both at level -1 mm. Hence, negative values represent bone loss. The same methodology is applied to determine horizontal buccal bone loss at level -3 and -5 mm.

Vertical buccal bone level is measured as the vertical distance from the buccal bone peak to the reference line at the level of the implant-abutment interface to the nearest 0.1 mm. Vertical buccal bone loss is calculated by subtracting the pre-operative vertical bone level from the 1-year vertical bone level. Hence, negative values represent bone loss.

Buccal soft tissue thickness is measured as the distance from the buccal bone surface to the buccal soft tissue profile at level -1 mm to the nearest 0.1 mm. Increase in buccal soft tissue thickness is calculated by subtracting its pre-operative value from the 1-year value. Hence, positive values represent tissue gain.

One week after surgery, patients will be asked how many analgesics have been taken. In addition, they will be asked to rate postoperative pain on a numeric rating scale (0-10).

At 1-year and 5-year follow-up the treating surgeon evaluates plaque at four sites around the implant (mesial, buccal, distal, palatal). Each area receives a score of 0 or 1, representing the absence or presence of plaque.

At 1-year and 5-year follow-up the treating surgeon evaluates bleeding on probing at four sites around the implant (mesial, buccal, distal, palatal). Each area receives a score of 0 or 1, representing the absence or presence of bleeding on probing.

At 1-year and 5-year follow-up the treating surgeon evaluates probing depth at four sites around the implant (mesial, buccal, distal, palatal). Probing depth is registered with a manual probe (University North Carolina Probe PCPUNC 156, Hu-Friedy, Frankfurt, Germany) and measurements are rounded up to the nearest 0.5 mm. A mean value is calculated per implant.

Changes in the distance from the implant-abutment interface to the first bone-to-implant contact (so-called marginal bone level) at the mesial and distal aspect of each implant as measured on 2D intra-oral radiographs.

Changes in buccal soft tissue profile as measured on superimposed digital surface models. An intra-oral scan is taken prior to implant surgery and at 1- and 5- year follow up. On the obtained digital models, an area of interest (AOI) at the buccal aspect was drawn for each site. The AOI extends from 0.5 mm below the soft tissue margin to 4 mm more apical. In mesio-distal dimension, the AOI reaches from the mesial to the distal line angle. The AOI may vary between sites because of individual anatomic differences but must be kept constant in each site across time points. A volumetric change (mm3) was calculated by designated software within the AOI and divided by the AOI surface (mm2). This results in the mean change in buccal soft tissue profile (mm).

Change in midfacial soft tissue level from surgery to 1-year and 5-year follow-up is calculated on digital surface models from in the same software (SMOP, Swissmeda AG, Zurich, Switzerland). First, a reference line is drawn connecting the middle of the incisal edge on both adjacent teeth at both timepoints. Then, the distance from this line to the buccal mucosal margin (so-called midfacial soft tissue level) is determined at the centre of each implant to the nearest 0.01 mm. Change in midfacial soft tissue level is calculated by subtracting midfacial soft tissue level from the preoperative situation from the one at 1-year and 5-year follow-up. Negative values indicate recession; positive values indicate vertical regrowth. Change in midfacial soft tissue level is assessed by a blinded examiner.

Change in mesial and distal papilla level from surgery to 1-year and 5-year follow-up is calculated at the mesial and distal aspect. The methodology is the same as described for the change in midfacial soft tissue level.

Pink Esthetic Score (PES) is registered by a trained and blinded examiner using frontal and occlusal clinical pictures taken at 1 year and 5-year follow-up. The PES results in a score from 0 (worst esthetic outcome) to 14 (perfect esthetic outcome).