Tissue Changes Following Connective Tissue Grafting and Two-stage Implant Placement. A Randomised Clinical Trial

Initially, 48 patients were recruited from new referrals to the Lab of Preventive Dentistry, Periodontology and Implant Biology, Aristotle University of Thessaloniki (AUTh) for surgical placement of at least one implant located in the upper/lower jaw in the anterior/posterior segment.

Study design An initial screening visit included full-mouth periodontal assessment, radiographic examination, fulfillment of inclusion/exclusion criteria and suitable patients (n=48) were randomised into either treatment Group; in the control Group (Group-A), a conventional surgical protocol was followed for implant placement, while in the test Group (Group-B) implants were placed in conjunction with an autologous CTG. Each Group was further categorized as having thin mucosa (≤2.5mm for Subgroups-AI/-BI) or thick mucosa (>2.5mm for Subgroups-AII/-BII) at the implantation site before implant placement (baseline=T0). Implants were exposed 3-4 months later (T1).

Surgical procedures A single implant system (Osseotite, Certain, parallel wall, Biomet 3i, Florida, USA; implants of 3.25/4.0 mm in diameter) was used in all cases. At T0, following local anaesthesia (lidocaine hydrochloride 2%, epinephrine 1:100000, Lignospan standard, Septodont, France), crestal incisions were performed and full-thickness flaps were raised for implant placement. Implants were placed at the level of the alveolar crest following the manufacturer's surgical guidelines and a two-stage protocol. Flaps were repositioned using absorbable sutures (polygalactic acid 5/0 sutures; PGA, medipac, Greece). In Group-B, a similar protocol was followed as in Group-A, with the exception that following implant placement a CTG was harvested from the palate, between the maxillary canine and the first molar (Liu & Weisgold, 2002) and was stabilised onto the lingual flap using a horizontal mattress suture. Standardised dimensions of the CTG (11×6×1.5mm) were sought to cover the implant's shoulder and extend 3-5 mm on the buccal and the lingual aspect of the alveolar ridge (Fig. 1). Scoring of the periosteum for coronal advancement of the flaps was mainly performed in Group-B (16 of 23 cases).

Post-operative care Post-operative pain and oedema were controlled by Ibuprofen, 600 mg. All participants were prescribed antibiotics (Amoxicillin, 500 mg per 8 hours for 5 days) and were instructed to rinse twice daily with chlorhexidine digluconate (0.12%) and to abstain from oral hygiene in the test area for one week. Any post-operative adverse events (i.e. swelling, suppuration, flap dehiscence, persistent pain) were recorded upon suture removal ten days after surgery.

Clinical assessments