Noninvasive incision design to prevent loss of attachment of adjacent implants in ridge augmentation

Guided bone regeneration (GBR) is a common procedure used to reconstruct deficient alveolar ridges for implant therapy.1, 2, 3 Tension-free primary closure, angiogenesis, space maintenance, and wound and grafting material stability are crucial to predict bone regeneration⁴ and depend on flaps being carefully designed to ensure the passive closure of wound edges after grafting.⁵ Defects next to preexisting implants may create difficulties because sulcular incision may lead to marginal bone loss at implants. Here, we reported our experience of successfully performing GBR adjacent to a preexisting dental implant and discussed concerns regarding flap design.

A 71-year-old woman presented at our department to restore the missing tooth 47 with a severe narrow ridge (Fig. 1A); GBR was necessary before the implant treatment. Cone beam computed tomography revealed a severe horizontal ridge deficiency at the edentulous ridge of tooth 47 area and marginal bone loss around the buccal area of the implant 46 (Fig. 1B). The soft tissue around the implant 46 appeared healthy, and this keratinized tissue was crucial to maintain the required circumstance. The soft-tissue connection around the implant was vulnerable to invasive treatment procedure. To retain this existing soft-tissue connection around the implant and prevent further bone loss, flap incisions were made through the following steps: (1) A crestal incision was created 1 mm away from the tooth 46 distal contact point to the retromolar region; (2) To create a wide surgical field, the crestal incision was extended bucco-anteriorly 2 mm from the mucogingival junction along the outline of the implant 46 gingival margin to the relative point at the mesial buccal coroner of implant 46; (3) A horizontal–anterior–lingual extent incision was created in a similar manner 2 mm away from the gingival margin because no marginal bone loss was observed at this aspect (Fig. 1C). After lingual flap advancement and decorticalization of the recipient bone bed, a tenting screw, allograft, and bioresorbable membrane were used (Fig. 1D). Tension-free primary closure was then achieved (Fig. 1E). Stitches were removed 2 weeks after surgery, and no wound dehiscence was noted during routine recall (Fig. 1F). No clinical changes in attachment or marginal bone loss at the implant 46 were noted (Fig. 1G). The results of GBR were positive, with the width of the ridge increasing from 2 to 7.5 mm, thus enabling implant placement surgery.

Figure 1.

Clinical photographs and radiographs of the patient. (A) The right mandibular second molar had severe periodontal destruction and had been extracted 3 months prior. A large horizontal deficiency at the edentulous ridge was observed. (B) Cone beam computed tomography revealed an initial defective bone morphology at tooth 47 and the loss of the buccal marginal bone at tooth 46. (C) Schematic and clinical photographs demonstrating the design of our scarf-like modified envelope flap. (D) Serial clinical photographs revealing lingual flap advancement, decortication of bone bed, and the placement of a tenting screw, freeze-dried bone allograft bone powder, and bioresorbable membrane after the scarf-like flap reflection. (E) The primary wound closure was achieved with a double-layer suture technique. (F) Intraoral image of the wound at 47 after stitches were removed. (J) Six-month follow-up cone beam computed tomography revealed remarkable outcomes in terms of bone gain and no further buccal marginal bone loss at the implant 46.

With the increasing prevalence of implant therapy, the demand for GBR near preexisting implants should also increase. Therefore, comprehensive flap designs for implant-adjacent sites are crucial. The advantages of our modified envelope flap design are that it preserves the scarf-like soft tissue around adjacent implants, prevents the weakening of existing attachments around implant necks, creates a wide surgical field for decorticalization, membrane fixation, and releasing procedures, and enables a vertical releasing incision to be made at the mesiobuccal end of the scarf if necessary.

Declaration of competing interest

All the authors declare no potential financial and nonfinancial conflicts of interest.