Timing of Soft Tissue Grafting Following Immediate Implant Placement

Official title

A Randomized Controlled Trial on the Timing of Soft Tissue Grafting Following Immediate Implant Placement

Overview

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. In all of the patients, a connective tissue graft (CTG) will be harvested and inserted into the buccal mucosa to increase soft tissue thickness around the immediately installed implant. However, included patients will be randomly allocated to either receive the CTG immediately after implant installation (Immediate soft tissue grafting, ISG = control group) or 3 months after implant installation (Delayed soft tissue grafting, DSG = test group). Forty sealed envelopes are prepared for that purpose, of which 20 are internally labeled as "DSG" and 20 as "ISG". Following IIP, a sealed envelope will be opened to reveal the treatment concept In both groups, a cutting implant is installed in an optimal 3D position. Socket grafting is performed with deproteinized bovine bone mineral to limit buccal bone resorption and to optimize soft tissue stability. In the ISG group, a pouch is made in the buccal mucosa using microsurgical instruments. Thereupon, a free gingival graft is harvested from the palatal mucosa in the premolar area and de-epithelialized to arrive at a CTG of about 1 mm thickness. Height and length are tailored to the dimensions of the site. Then, the CTG is brought into the pouch and fixed with two single sutures onto the buccal mucosa. Finally, a healing abutment is installed, which is replaced by a provisional implant crown 2 days later. In the DSG group, implant placement, socket grafting and installation of a provisional implant crown occur as described above. In contrast, a buccal pouch is performed 3 months after implant installation. Graft harvesting, adaptation and fixation are performed as described above. A small-field low-dose CBCT is taken at the 1-year and 5-year follow-up in order to measure buccal bone resorption as compared to the baseline dimensions in designated software.

Detailed description

Patients with a single failing tooth in the anterior maxilla will be included after a clinical examination and evaluation of a small-field low-dose CBCT. An intra-oral scan will be taken in order to make a surgical guide. A cutting implant with variable thread design (BLX, Straumann) will be installed using the surgical guide in order to sufficient primary implant stability.

Thereafter, the gap between the implant surface and buccal bone wall is filled with deproteinized bovine bone mineral (Bio-Oss, Gheistlich Pharma).

At this point, a closed envelope is opened and the patient gets assigned to either ISG or DSG group.

In the immediate soft tissue grafting group, a de-epithelialized free gingival graft was inserted in a buccal pouch to augment the buccal soft tissues. The graft was fixed with single sutures (Seralon 6/0, Serag Wiessner, Naila, Germany).

In the delayed soft tissue grafting group, the same procedure was performed 3 months after implant placement.

In both groups, patients received an immediate, screw-retained temporary crown. Restorations were installed within the first 48h after implant placement.

Sutures were removed 1 week after soft tissue grafting.

Interventions

• Procedure Soft tissue grafting
  A pouch is made in the buccal mucosa using microsurgical instruments. Thereupon, a free gingival graft is harvested from the palatal mucosa in the premolar area and de-epithelialized to arrive at a CTG of about 1 mm thickness. Height and length are tailored to the dimensions of the site. Then, the CTG is brought into the pouch and fixed with two single sutures (Seralon 6/0, Serag Wiessner, Naila, Germany) onto the buccal mucosa.

Primary outcome measures

• Buccal bone resorption (mm) [Time frame: 1-, 5-year]

Secondary outcome measures (8)

• Changes in buccal soft tissue profile (mm) [Time frame: 1-, 5-year]
• Changes in midfacial soft tissue level (mm) [Time frame: 1-, 5-year]
• Pink Esthetic Score [Time frame: 1-year]
• Mucosal Scarring Index [Time frame: 1-year]
• Marginal bone level changes (mm) [Time frame: 1-,5-year]
• Probing depth (mm) [Time frame: 1-,5-year]
• Plaque (%) [Time frame: 1-,5-year]
• Bleeding on probing (%) [Time frame: 1-,5-year]

Eligibility criteria

Inclusion criteria

• At least 20 years old
• Good oral hygiene defined as full-mouth plaque score ≤ 25% (O'Leary et al. 1972)
• Presence of an incisor, cuspid or premolar in the maxilla that needs to be extracted for any reason with at least one neighboring tooth present
• At least 3 mm bone available at the apical or palatal aspect of the alveolus as assessed on CBCT to ensure primary implant stability
• Intact buccal bone wall at the time of extraction
• Written informed consent

Exclusion criteria

• Pregnancy
• Systemic diseases
• Smoking
• Suppuration
• > 1 mm gingival asymmetry between the failing and contralateral tooth
• Untreated periodontal disease; untreated caries lesions

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: Yes

Study design

Allocation

Randomized

Model

Parallel assignment

Masking

Double blind

Primary purpose

Treatment

Study locations

Belgium · 1 center

• Ghent University — Ghent

Publications

• O'Leary TJ, Drake RB, Naylor JE. The plaque control record. J Periodontol. 1972 Jan;43(1):38. doi: 10.1902/jop.1972.43.1.38. No abstract available. PMID 4500182
• Furhauser R, Florescu D, Benesch T, Haas R, Mailath G, Watzek G. Evaluation of soft tissue around single-tooth implant crowns: the pink esthetic score. Clin Oral Implants Res. 2005 Dec;16(6):639-44. doi: 10.1111/j.1600-0501.2005.01193.x. PMID 16307569
• Zuiderveld EG, van Nimwegen WG, Meijer HJA, Jung RE, Muhlemann S, Vissink A, Raghoebar GM. Effect of connective tissue grafting on buccal bone changes based on cone beam computed tomography scans in the esthetic zone of single immediate implants: A 1-year randomized controlled trial. J Periodontol. 2021 Apr;92(4):553-561. doi: 10.1002/JPER.20-0217. Epub 2020 Sep 11. PMID 32918332
• Seyssens L, Eghbali A, Christiaens V, De Bruyckere T, Doornewaard R, Cosyn J. A one-year prospective study on alveolar ridge preservation using collagen-enriched deproteinized bovine bone mineral and saddle connective tissue graft: A cone beam computed tomography analysis. Clin Implant Dent Relat Res. 2019 Oct;21(5):853-861. doi: 10.1111/cid.12843. Epub 2019 Aug 28. PMID 31456345
• Wessels R, De Roose S, De Bruyckere T, Eghbali A, Jacquet W, De Rouck T, Cosyn J. The Mucosal Scarring Index: reliability of a new composite index for assessing scarring following oral surgery. Clin Oral Investig. 2019 Mar;23(3):1209-1215. doi: 10.1007/s00784-018-2535-6. Epub 2018 Jul 3. PMID 29971512
• Struys T, Christiaens V, De Bruyckere T, Pitman J, Van Hove PJ, Cosyn J. A Randomized Controlled Trial on the Timing of Soft Tissue Augmentation in Immediate Implant Placement: Soft Tissue Changes and Esthetic Outcome. Clin Implant Dent Relat Res. 2025 Feb;27(1):e70013. doi: 10.1111/cid.70013. PMID 39980395
• Cosyn J, Struys T, Van Hove PJ, De Buyser S, De Bruyckere T. A Randomized Controlled Trial on the Timing of Soft-Tissue Augmentation in Immediate Implant Placement: Hard-Tissue Changes and Clinical Outcome. J Clin Periodontol. 2024 Nov;51(11):1534-1544. doi: 10.1111/jcpe.14060. Epub 2024 Sep 1. PMID 39218777

Identifiers

NCT: NCT05537545 · ONZ-2022-0258

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗