It is now well-known that tooth loss results in a loss of natural anatomical morphology as both hard and soft tissue remodel. The replacement of a tooth by a dental implant whether in the delayed or the immediate scenario will not stop the process of remodeling, since bone resorption at a new extraction site is continuous,1 with the greatest loss occurring during the first month. This remodeling results in a loss of vertical ridge height and the displacement of the buccal wall in a palatal direction, whether in the maxilla or the mandible.2 Additionally, lingual resorption will occur in the mandible to such an extent that there will remain a centralized, narrow ridge.3 With time, the continual loss of tissue volume will both hamper the placement of a dental implant but also reduce the aesthetic outcome that can be achieved. Both bone4 and soft tissue5 techniques have now been developed to address this loss in volume morphology.
Socket preservation is advocated to reduce the loss of alveolar bone volume, and to allow implant placement with high primary stability and provide newly-regenerated tissues for osseointegration.6 Both autogenous bone grafts and bone substitutes are now used for preservation of the socket volume7,8 with the intention of avoiding extensive future bone grafting. Lindhe et al9 examined the tissue composition of extraction sockets that had been grafted with deproteinized bovine bone mineral that had been allowed to heal for 6 months; they found that the healing had been retarded and that Bio-Oss particles (Geistlich Pharma, Wohlhusen, Switzerland) were not resorbed but became surrounded by new bone, concluding that this could explain why such grafted sites appear not to undergo dimensional change.
In a wish to produce some clarity as to the superiority, or not, of particular postextraction ridge preservation techniques, Darby et al10 carried out a review that concluded no technique was better than another.
Vanhoutte et al11 have assessed the alveolar ridge preservation procedures in humans with particular reference to soft tissue profile. One of the objectives of their study was to evaluate “saddled” connective tissue grafts in combination with the insertion of slowly resorbing biomaterials into the extraction socket. They found that such a combination could almost counteract bony remodeling in terms of external soft tissue profile. However, this study only continued for 3 months postextraction.
Logically, primary wound closure will be required for any socket preservation technique to reduce the loss of graft material, inhibit bacterial infection and subsequent graft failure,12 but also to minimize tissue shrinkage, and thus maintain aesthetics at the extraction site. The usual method of wound closure is simply to coronally advance the vestibular tissue with a coronally directed displacement of the mucogingival junction, resulting in the less than optimal situation of a reduced width of keratinized gingival tissue.5,13 Other flap manipulation techniques have been developed to provide wound closure over the socket preservation site.14–16 Thalmair et al17 reported on the free soft tissue graft, concluding that such a ridge preservation technique will not entirely compensate for alveolar ridge reduction, and does not avoid postoperative external contour shrinkage. Stimmelmyer et al18 have recently shown some improvement in the technique by combining a free graft with a subepithelial connective tissue graft. However, such techniques have no intrinsic and continued vascularity—they rely on neovascularization and are, therefore, in danger of sloughing and failure.
Where the extraction socket is either distally or mesially bordered by an edentulous ridge, the author has developed a technique that produces a predictable soft tissue coverage of the augmented extraction socket, thus fully protecting the site from failure but also sustaining the vascularity of the graft to allow predictable angiogenesis: the “Sliding Full-Thickness Pedicle Flap for Primary Wound Closure of the Socket Preservation Site.”
The following case reports detail the surgical procedure of the “Sliding Pedicle Flap” technique.
Methods and Materials
All illustrations are from patients presenting at a private practice dedicated to periodontics, dental implants, and advanced restorative techniques. In cases where teeth were determined as beyond further conservative therapy, the patients were offered the options of further treatment that included extraction and dental implant replacement therapy. All patients signed informed consent before treatment.
Clinical case 1
A 68-year-old woman presented with what appeared an upper right first molar. The tooth exhibited Grade 3 mobility and was very painful to percussion. Buccal periodontal probing displayed pocketing in excess of 7 mm. Radiographic evaluation revealed the tooth was in fact a second molar that had drifted mesially; there was a lack of mesial bone support (Figure 1a). The patient described the loss of a molar tooth in this region during her teens (see Figures 1b and 1c).
Pre-extraction: 1 hour prior to surgery the patient received systemic coverage (2 g, amoxicillin (or 600 mg clindamycin when allergic); 400 mg, ibuprofen; and 2 mg, dexamethasone. Additionally, the patient received a mouth rinse of chlorhexidine gluconate, 2%, 20 minutes prior to surgery.
All surgery was carried out under intravenous sedation (midazolam) and local anesthesia (articaine 4%, Septodont, Saint-Maur-Des-Fossés, France). The tooth was “atraumatically” extracted (Figure 1d). Following extraction, incisions were made in the distal edentulous region to produce a full-thickness pedicle flap (Figures 1e–g). The socket was debrided and Bio-Oss granules placed in the void (Geistlich Pharma); particle size 0.25–1.0 mm (Figure 1h) and covered with a resorbable membrane (Bio-Gide, Geistlich Pharma; Figure 1i). Wound closure was obtained by repositioning the distal full-thickness edentulous flap mesially. The pedicalized flap was then secured using 5.0 Prolene sutures as shown in Figures 1j and 1k. The wound site was then covered with Eugenol-free Coe-Pak dressing (GC United Kingdom Ltd, Newport, Pagnell, UK). Healing was uneventful and at 3-weeks postsurgery the sutures were removed (Figure 1l). Figures 1m and 1n show the degree of soft tissue maturity at 5-months just prior to implant surgery, while the periapical radiograph (Fig. 1o) shows the degree of “bony” in-fill of the socket at that time.
Clinical case 2
A 52-year-old woman wished for the replacement of an unsalvageable upper right first molar tooth (Figures 2a and b). Following the same surgical protocol as in Case 1, the tooth was removed under intravenous sedation (Figures 2c and d). Following extraction, incisions were made in the distal edentulous region to produce a full-thickness pedicle flap according to the principals shown in the schematic (see Figures 1g and e) and fully reflected (Figures 2f and g). The socket was debrided and Bio-Oss granules placed in the void (Geistlich Pharma, Wohlhusen, Switzerland); particle size 0.25–1.0 mm (Figure 2h) and covered with its resorbable membrane (Bio-Gide, Geistlich Pharma, Wohlhusen, Switzerland; Figure 2i). Wound closure was obtained by repositioning the distal full-thickness edentulous flap mesially. The pedicalized flap was then secured using 5.0 Prolene sutures as shown in Figures 2j and k. The wound site was then covered with Eugenol-free Coe-Pak dressing (GC United Kingdom Ltd). Healing was uneventful and at 3-weeks postsurgery the sutures were removed. Figures 2l and m show the degree of soft tissue maturity at 5-months just prior to implant surgery, while the periapical (Figure 1n) shows the degree of “bony” in-fill of the socket at that time. At the time of implant placement, a minimal flap reflection was carried out; Figures 2o and p show the degree of bony anatomy that was present (please note that a transcrestal sinus lift/graft and subepithelial connective tissue graft was carried out simultaneously with the implant placement.
As stated, following tooth extraction, the vacant socket and local adjacent alveolus will resorb.1–3 Such resorption, if allowed to continue uncontrolled, may well have such an adverse effect on the hard and soft tissue morphology that the placement of dental implants may not be possible without adjunctive surgical procedures. Where bone loss already exists at a proposed extraction site, as a result of existing “infections” or periodontal disease, the ensuing alveolar remodeling will be more profound. Socket augmentation at the time of extraction, whether autogenic, allogenic, or by xenograft, has the intention of preserving or restoring the alveolar morphology, making it more amenable to implant insertion.19,20 However, a major problem with socket preservation is the achievement of primary wound closure.15,16 The “sliding pedicle flap,” as described here, robustly contains and protects the graft material and its membrane, so preventing their dislodgement. Continued wound coverage, as described here, depends on the maintenance of blood supply and angiogenesis: This is provided by the uninterrupted sulcular blood supply of this flap design during its repositioning. Preparation of the flap and the recipient site will maximize blood supply for blood clot formation and organization so preventing necrosis and minimizing final mobility to prevent tearing away from the recipient site which would otherwise risk graft loss. Both the clinical and radiographic results of the 2 case examples shown here demonstrate the stability of the flap design and its consequent success in aiding socket preservation.