Patients undergoing single immediate implant placement (IIP) in the premaxilla will be invited to participate in this randomized controlled trial (RCT). Prior to surgery, a small- field low-dose cone beam computed tomography (CBCT) is taken to verify the integrity of the facial bone wall and an adequate amount of apical and palatal bone availability for implant anchorage. 54 patients will be randomly assigned to either conventional connective tissue graft (C-CTG), scarf tissue graft (S-CTG) or dual zonde conept (DZ). Sealed envelopes are prepared for that purpose, of which 18 are internally labeled as C-CTG, 18 as S-CTG and 18 as DZ. Following IIP, a sealed envelope will be opened to reveal the treatment concept. Successful regeneration (primary outcome) 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. Secondary outcomes include: horizontal buccal bone loss, vertical buccal bone loss, increase in buccal soft tissue thickness, patient-reported outcomes, plaque, bleeding on probing, probing depth, marginal bone loss, change in buccal soft tissue profile, midfacial soft tissue level, mesial and distal papilla level, Pink Esthetic Score.
This study is a three-arm randomized controlled trial comparing conventional connective tissue grafting (C-CTG) with two alternative soft-tissue augmentation approaches-scarf CTG (S-CTG) and the dual-zone technique (DZ)-in patients receiving single immediate implant placement in the anterior maxilla. The primary objective is to determine which method results in the highest proportion of sites showing successful regeneration 1 mm below the implant shoulder. Secondary outcomes assess clinical parameters, patient-reported pain and medication use, hard- and soft-tissue dimensional changes, and esthetic scores. Eligible participants are adults with good oral hygiene and an anterior maxillary tooth requiring extraction with adequate bone support. Exclusion criteria include pregnancy, systemic disease, smoking, active infection, periodontal disease, and extensive gingival asymmetry. Fifty-four patients will be randomized equally to the three intervention groups; allocation is concealed and outcome assessors are blinded. All patients receive immediate implant placement with socket grafting. The three groups differ only in the soft-tissue augmentation method: C-CTG involves placing a connective tissue graft in a buccal pouch; S-CTG uses a smaller graft fixed at the transmucosal aspect without a pouch; DZ relies on graft condensation beneath the soft tissue without a connective tissue graft. Standard postoperative care is provided in all groups. Hard- and soft-tissue changes are assessed using cone-beam CT, clinical measurements, intra-oral scans, and standardized photography at baseline and follow-up visits. Successful regeneration is defined by maintenance of buccal soft tissue at the specified reference level. Patient-reported postoperative pain and analgesic use are recorded after one week. Esthetic outcomes are evaluated using a validated scoring system at 1- and 5-year follow-up. Data will be analyzed using appropriate statistical tests for group comparisons, including mixed models for tissue changes, Fisher's exact test for the primary outcome, and non-parametric tests for variables that are not normally distributed. A two-sided significance level of 5% is applied throughout.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
54
A pouch is made in the buccal mucosa extending 3 mm below the buccal bone crest. Thereupon, a free gingival graft is harvested from the palatal mucosa and de-epithelialized. The CTG is brought into the pouch and fixed with two single sutures onto the buccal mucosa. A healing abutment is installed, which is replaced by a provisional implant crown 2 days later. Sutures are removed 1 week after the surgery.
No pouch is made in the recipient site. A free gingival graft is harvested from the palatal mucosa and de-epithelialized. The small CTG is fixed at the transmucosal aspect onto the buccal mucosa. A healing abutment is installed, which is replaced by a provisional implant crown 2 days later. Sutures are removed 1 week after the surgery.
DBBM is applied and condensed up to the level of the buccal soft tissue margin. A healing abutment is installed, which is replaced by a provisional implant crown 2 days later. Usually, sutures are not needed in this group, unless minimal papilla opening was required to extract the tooth. In that case, sutures will be removed after 1 week.
Ghent University Hospital
Ghent, East Flanders, Belgium
RECRUITINGSuccesful regeneration (%)
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.
Time frame: 1-, 5 year
Horizontal buccal bone loss -1, -3 and -5 (mm)
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.
Time frame: 1-, 5 year
Vertical bone loss (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.
Time frame: 1-, 5 year
Increase in buccal soft tissue thickness (mm)
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.
Time frame: 1-, 5 year
Patient-reported outcomes
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).
Time frame: 1-, 5 year
Plaque (%)
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.
Time frame: 1-, 5 year
Bleeding on probing (%)
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.
Time frame: 1-, 5 year
Probing depth (mm)
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.
Time frame: 1-, 5 year
Marginal bone loss (mm)
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.
Time frame: 1-, 5 year
Change in buccal soft tissue profile (mm)
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).
Time frame: 1-, 5 year
Change in midfacial soft tissue level (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.
Time frame: 1-, 5 year
Change in mesial and distal papilla level (mm)
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.
Time frame: 1-, 5 year
Pink Esthetic Score
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).
Time frame: 1-, 5 year
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