Recently a two-layer, porcine-derived collagen matrix (Geistlich Mucograft®) has been investigated for the treatment of dehiscence defects around teeth and for augmenting keratinized tissue around teeth and implants supporting fixed prosthetic restorations.1-4 The matrix is composed of type I and type III collagen and is thicker than conventional collagen membranes. Intraoral soft tissue around the periphery of the graft grows through, rather than under, the matrix, as it is replacing it.
A 62-year old healthy, non-smoker male presented with a 7 mm “v” shaped gingival recession defect extending to the apex of the upper left central incisor (Figs. A, B). There was no underlying medical history of any significance. The tooth was failing endodontically with a previous root filling and apicoectomy surgery. The upper left central incisor was atraumatically extracted, followed by removal of granulation tissue from within the socket. A small pouch was created and extended a few millimeters beyond the intact bone margins. Complete loss of the buccal plate was noted, and in order to prevent collapse of the graft, a collagen haemostatic plug was placed in the extraction socket (Hemospon Collagen CubesTM, TechNew, Brazil). Geistlich Mucograft® was cut to size so that the edges extended beyond the bone margins to ensure coverage by the overlying flap. It was stabilized to the overlying flap margins with 6-0 monofilament nylon interrupted single sutures (Figs. C-F). A provisional resin-bonded bridge was cemented, avoiding contact with the soft tissues or graft.
An uneventful healing was noted at one week, with Geistlich Mucograft® showing some surface sloughing similar to the healing anticipated with a free gingival graft (Fig. G). The sutures were removed, and the patient was advised to continue using 0.2% chlorhexidine thrice daily and refraining from tooth brushing around the surgical site. After six-weeks of healing (Fig. H), an early delayed (Type II) implant placement protocol was used in conjunction with simultaneous guided bone regeneration. Complete loss of the buccal plate was noted. Nonetheless, there was apical bone to the floor of the nose to offer adequate primary stability (Fig. I).
A Straumann® SLActive (Straumann AG, Switzerland), Tapered Effect, tissue-level type implant was placed in an ideal 3-dimensional position, resulting in a 6 mm dehiscence of the roughened surface of the implant. Following corticitomy, autologous bone shavings were collected from the adjacent area and placed over the implant, followed by blood soaked deproteinized bovine bone substitute (Geistlich Bio-Oss®), which was covered by a bi-layered porcine-derived collagen barrier membrane (Geistlich Bio-Gide® – Figs. J-L). The sutures were removed after one-week (Fig. M), and the implant exposure surgery was carried out after eight weeks using a 4 mm soft tissue punch (Fig. N). A laboratory-made implant provisional crown was used for manipulation of soft tissues to optimize the pink aesthetics (Fig. O). Endodontic treatment in upper right central incisor was revised and non-vital, and in-out bleaching was carried out with concomitant home bleaching in the remaining maxillary dentition. After optimizing pink aesthetics, a screw-retained, one-piece, metal-ceramic crown was provided.
After two- and five-years, stable peri-implant soft tissues and optimal pink and white aesthetics were noted. The mucogingival line was corrected, and 5 mm of keratinized mucosal width was restored (Figs. P, Q). Radiographs demonstrated stable bone levels, and a CBCT scan revealed a maximum labial bone thickness of 3.6 mm in total, 1.6 mm labial bone thickness was noted at the junction of the SLA surface and the smooth collar, and the bone extended vertically beyond this junction, albeit not in contact with the implant surface (Figs. R, S).