It is now well-known that tooth loss results in a loss of

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1 CASE LETTER Sliding Full-Thickness Pedicle Flap for Primary Wound Closure of the Socket Preservation Site Shane J. J. McCrea, MMedSci, MSc, BDS INTRODUCTION 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 bone 4 and soft tissue 5 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 volume 7,8 with the intention of avoiding extensive future bone grafting. Lindhe et al 9 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 al 10 carried out a review that concluded no technique was better than another. Vanhoutte et al 11 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. Private practice, The Dental Implant and Gingival-Plastic Surgery Centre, Bournemouth, Dorset, UK; and The British Society of Oral Implantology, Southport, UK. Corresponding author, shanemccrea@aol.com DOI: /AAID-JOI-D 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 Thalmair et al 17 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 al 18 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). 372 Vol. XLI/Special Issue/2015

2 McCrea FIGURE 1. (a) Preoperative periapical radiograph. (b) Initial clinical presentation. (c) Pre-extraction site displaying the extent of the distal edentulous site. (d) Tooth 16 has been removed. (e, f) The classical incisions for producing a full-thickness sliding pedicle flap have been made through the distal soft tissue. (g) This schematic depicts the classical incisions; the shaded area shows the buccal tissue that will be sacrificed to allow the mesial repositioning of the distal pedicalized flap. (h) Bio-Oss granules have been placed into the socket voids. (i) Bio-Gide membrane is placed over the Bio-Oss. (j, k) The full-thickness mucoperiosteal flap is detached from the underlying bone and repositioned over the Bio-Gide membrane that covers the extraction socket. Suturing has been carried out using 5.0 Prolene (Ethicon, Johnson and Johnson, Somerville, NJ). (l) Socket preservation site at 3-weeks postop, prior to suture removal. (m, n) Socket preservation site at 5-months postop. (o) Periapical radiograph of site at 5-months postop. Journal of Oral Implantology 373

3 Wound Closure and the Sliding Full-Thickness Pedicle Flap FIGURE 2. (a, b) Site 17 and 16 prior to removal of tooth 16. (c, d) Tooth 16 has been removed. (e) Outline of the distal incisions. (f, g) Fullthickness mucoperiosteal flap has been fully reflected, having removed the V-shaped sacrificial tissue from the buccal wall of the 16 socket. (h) Bio-Oss granules have been placed into the socket voids and the buccal dehiscence. (i) Bio-Gide membrane over the socket site. (j, k) The distal flap has been repositioned mesially and secured over the Bio-Gide/socket using 5.0 Prolene. (l, m) Socket preservation site 16 at 5-months postop. (n) Periapical radiograph of site 16 prior to implant placement. (o, p) Minimal full-thickness flap reflection at site 16 to demonstrate the extent of the preserved socket site during implant placement. 374 Vol. XLI/Special Issue/2015

4 McCrea The patient described the loss of a molar tooth in this region during her teens (see Figures 1b and 1c). Extraction 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 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 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 fullthickness 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. DISCUSSION 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. REFERENCES 1. Pietrokovski J, Massler M. Alveolar ridge resorption following tooth extraction. J Prosthetic Dent. 1967;17: Pietrokovski J, Starinsky R, Arensburg B, Kaffe I. Morphologic Characteristics of Bony Edentulous Ridges. J Prosthodontics. 2007;16: Wan WL, Wong TLT, Wong MCM, Lang NP. A systematic review of post-extractional alveolar hard and soft tissue dimensional changes in humans. Clin Oral Impl Res. 2012;23: Ashman A. Ridge preservation: important buzzwords in dentistry. Gen Dent. 2000;48: McCrea SJ. The washing line suture technique to secure the subepithelial connective tissue graft. J Oral Implantol. 2014;40: Pagni G, Pellegrini G, Giannobile WV, Rasperini G. Post-extraction alveolar ridge preservation: biological basis and treatments. Int J Dentistry. 2012;2012: Lasella JM, Greenwell RI, Miller RL, et al. Ridge preservation with freeze-dried bone allograft and a collagen membrane compared to extraction alone for implant site development: a clinical and histologic study in humans. J Periodontol. 2003;74: Eickl S, Zuhr O, Wachtel H, Stappert CFJ, Stein JM, Hurzeler MB. Dimensional changes of the alveolar ridge contour after different socket preservation techniques. J Clin Periodontol. 2008;35: Lindhe J, Cecchinato D, Donati M, Tomasi C, Lilienberg B. Ridge preservation with the use of deproteinized bovine bone mineral. Clin Oral Implants Res. 2014;25: Darby I, Chen ST, Buser D. Ridge preservation techniques for implant therapy. Int J Oral Maxillofac Implants. 2009;24: Vanhoutte V, Rompen E, Lecloux G, Rues S, Schmitter M, Lambert F. A methodological approach to assessing alveolar ridge preservation procedures in humans: soft tissue profile. Clin Oral Implant Res. 2014;25: Journal of Oral Implantology 375

5 Wound Closure and the Sliding Full-Thickness Pedicle Flap 12. Grimm WD, van der Heoven H, Langendijk PS, et al. The influence of sulphate reducing bacterial colonization of 2 different bioresorbable barrier membranes for GTR. An 18-month case-controlled micro-biologic and clinical study. Int J Periodontics Restorative Dent. 2000;20: Becker W, Becker BE. Guided tissue regeneration for implants placed into extraction sockets and for implant dehiscences: surgical techniques and case report. Int J Periodontics Restorative Dent. 1990;10: Kao SY, Yeung TC, Hung KF, et al. Transpositioned flap vestibuloplasty combined with implant surgery in the severely resorbed atrophic edentulous ridge. J Oral Implantol. 2002;28: Fugazzotto PA. Maintaining primary wound closure after guided bone regeneration procedures: Introduction of a new flap design and preliminary results. J Periodontol. 2006;77: El Chaar ES. Soft tissue closure of grafted extraction sockets in the posterior maxilla: the rotated pedicle palatal connective tissue flap technique. Implant Dent. 2010;19: Thalmair T, Hinze M, Bolz W, Wachtel H. The healing of free gingival autografts for socket seal surgery: a case report. Eur J Esthet Dent. 2010;5: Stimmelmayr M, Güth JF, Iglhaut G, Beuer F. Preservation of the ridge and sealing of the socket with a combination epithelialized and subepithelial connective tissue graft for management of defects in the buccal bone before insertion of implants: a case series. Br J Oral Maxillofac Surg. 2012;50: Minsk L. Extraction-site ridge preservation. Compend Contin Educ Dent. 2005;26:272, Keith JD Jr, Salama MA. Ridge preservation and augmentation using regenerative materials to enhance implant predictability and esthetics. Compend Contin Educ Dent. 2007; 28: Vol. XLI/Special Issue/2015