Failure of a natural tooth may not permit placement of an implant at the time of extraction due to insufficiency in available bone to house the implant. Reconstruction of the extraction socket frequently involves both hard and soft tissue augmentation to provide a site that can house the implant and ridge contours that mimic the adjacent natural anatomy. This situation becomes more problematic in the maxillary anterior due to the anatomy and the lower density of the bone of the premaxilla.
Interpositional Vascularized Augmentation Neogenesis
The solution is the interpositional vascularized augmentation neogenesis (IVAN), which consists of hard tissue grafts, various barrier membranes, and closure with the pediculated connective tissue graft (PCTG). The modified IVAN (mIVAN) technique achieves the necessary goals and may be used in both delayed and immediate placement situations.
We present a case showing use of the mIVAN technique with a delayed implant placement and long-term follow-up demonstrating hard and soft tissue maintenance. When healthy dentition is present, the “triangle of bone”1 of the premaxilla has a thin facial bone plate overlying the roots with natural dehiscence or fenestrations.2,3 When the natural tooth fails related to endodontic origin, the facial plate at the root may be partially or completely absent, preventing placement of an implant at the time of extraction.4 In such cases, a delayed approach may be necessary, with grafting of the socket for site development, accommodating eventual implant placement. This grafting may involve only hard tissue replacement and, during the healing phase, may require soft tissue augmentation to achieve site closure and contain the hard tissue augmentation. Additionally, augmentation of the soft tissue may be necessary to provide adequate attached gingiva.
Simultaneously rebuilding the soft tissue with hard tissue augmentation in the extraction socket frequently becomes difficult due to poor blood supply in the overlaying soft tissue graft. To circumvent this issue, a vascularized interpositional periostal connective tissue flap (VIP-CT) was developed as an anteriorly based pediculated tissue of palatal submucosa.5 Its maintained blood supply allows graft survival on poorly vascularized hard tissue augmentation placed during the same surgery.6 The advantage is that no coronal flap advancement is required, so loss of keratinized gingiva does not result and allows preservation of the papilla.
A 28-year-old female patient presented with a complaint of pain and mobility in the maxillary anterior. Examination noted a porcelain fused to a metal crown on the right central incisor; grade 1 mobility was present with a fistula at the apical aspect of the tooth (Figure 1). A periapical radiograph was taken and showed prior endodontic treatment performed on the incisor before restoration with the crown. Further, we identified a vertical root fracture with associated apical radiolucency (Figure 2). Treatment recommendation was extraction of the failing tooth and replacement with an implant and restoration with a single crown.
The tooth was extracted, and examination of the extraction socket noted an absence of the facial wall. A 15c scalpel blade was introduced into the facial aspect of the socket to create a split thickness tunnel in the soft tissue, attempting to keep the periosteum attached to the underlying bone (Figure 3). The extraction socket was thoroughly curetted to remove any residual tissue associated with the tooth. A resorbable membrane was curled into an ice cream cone shape and inserted into the extraction socket on the facial aspect, covering the osseous defect on the facial wall.7
An incision was made on the palate, starting at the mesial aspect of the 1st molar 2–3 mm apical to the gingival margin to avoid entry into the lingual gingival sulcus of the teeth and carried anteriorly to the extraction socket in a single incision technique for connective tissue graft (CTG) harvesting.8 Another incision was made parallel to the first incision 4mm closer to the palatal midline. The donor tissue was detached at the posterior end and kept attached at its anterior end to maintain blood supply to the tissue once it was flipped over the extraction socket (Figure 4). The mobilized palatal donor tissue is rotated anteriorly to cover the extraction site, maintaining the orientation of the tissue with respect to superior surface (facing the soft tissue) and inferior surface (facing the palate; Figure 5).
A piece of resorbable collagen membrane was trimmed as previously described (ice cream cone shape) to cover the facial missing wall within the socket.9 The membrane selected was a bi-layer porcine collagen membrane, Geistlich Bio-Gide (Geistlich, Baden Baden, Germany). The non-artificially cross-linked porcine-derived collagen membrane results in early vascularization and subsequent bone formation.10,11
A layer of xenograft (bovine) Bego OSS, (Bego, Bremen, Germany) is placed against the previously placed collage membrane on the facial wall in the socket to compensate for socket remodeling during healing (Figure 6). The socket itself is filled with autogenous bone, harvested from the palate (after PCTG elevation) using a bone scraper (Safescraper Twist; Meta, Correggio, Italy). This ensures that the implant is surrounded by autogenous bone only when placed.
The palatal connective tissue was flipped to cover the hard tissue graft placed in the socket (Figure 7). Closure of the surgical field was accomplished with resorbable polyglycolic acid and caprolactone suture material (Glycolon; Resorba Medical GmbH, Nuremberg Germany). Sling sutures were placed to close the palatal incision, utilizing the teeth to aid in immobilization of the tissue and compaction to the underlying bed, thereby preventing hematoma formation at the donor site (Figure 8). An Essix-type retainer was inserted—created with an ovate pontic from an impression taken during the consultation appointment—to be worn during the initial 3-week site healing period (Figure 9).
The patient returned at 3 weeks postsurgically, and the site demonstrated healing at the palatal donor site. Minimal inflammation was noted at the socket tissue margins, and coverage of the crest was not completely keratinized at the center (Figure 10). The facial ridge contour was maintained, providing a natural curvature with the adjacent sites.
A fixed resin bonded (Maryland) bridge created from the impression taken at the surgical consultation appointment was tried in and luted to the abutment teeth following acid etching. It was cemented (Figure 11) with Multilink Automix, a dual-cure resin cement (Ivoclar Vivadent AG, Ellwangen, Germany). Gingival margin position was coronal to the position on the contralateral central incisor, and some expected apical tissue movement was anticipated during site healing over the next few months.
At 4 months postaugmentation, the patient presented for Phase Two (Figure 12). The provisional resin bonded bridge was removed. A depression was present between the papilla with keratinized tissue present, related to the ovate pontic at the crests superior aspect. Slight loss of facial contour was noted at the augmented extraction site (Figure 13). A cone beam computerized tomography (CBCT) demonstrated the width of the ridge was sufficient for implant placement; the socket was filled with organized bone (Figure 14). A surgical stent was fabricated from an impression of the arch and inserted; a pilot drill in a surgical handpiece was guided with the stent to create the initial osteotomy, and subsequent drills were utilized to finalize the site for implant placement. A 4.1 × 13 mm implant (RSX Semados, Bego, Bremen, Germany) was placed into the osteotomy (Figure 15). The slight loss in the facial contour was addressed using a connective tissue graft harvested from the palate. The graft was inserted and fixated with a suture to bulk the facial contour, mirroring the adjacent central incisor (Figure 16). A periapical radiograph was taken to document implant placement in relation to the crest and adjacent teeth (Figure 17).
An immediate provisional was inserted and the fixation screw tightened to 30 Ncm with a torque wrench. Gingival position was coronal to the contralateral incisor, and some apical repositioning was expected during site healing (Figure 18). Contour of the immediate provisional crown and facial aspect of the arch blended with the surrounding area gave a natural appearance (Figure 19). The patient was dismissed with instructions to maintain a soft diet and not bite anything with the provisional crown.
At 4 months post-implant placement, the patient returned to initiate the implant final restoration. A CBCT was taken, demonstrating bone in contact with the entire implant and, in cross-section, the contour of the facial showed well trabeculated bone (Figure 20). The screw-retained provisional crown was removed, an open tray impression coping was affixed to the implant, and a full arch impression was taken. The screw-retained provisional crown was reinserted. The laboratory created a screw-retained restoration to be inserted in the patient. The esthetic results mimicked the contralateral incisor both in gingival position as well as ceramic shading, yielding a natural appearance (Figure 21).
The patient presented for a posttreatment 12-month recall appointment. A periapical radiograph was taken to check stability of the crestal bone level (Figure 22). Crestal bone position remained stable and matched the position achieved at implant placement. A natural esthetic harmony had been achieved that will be stable long-term (Figure 23).
Various hard tissue augmentation products are clinically available for socket grafting, and bovine products have shown repeatable predictability.12 That said, these graft products demonstrate better results when combined with a resorbable membrane. Higher hard tissue graft yields have been reported with membrane usage.13,14 Socket preservation using bovine bone and porcine collagen membrane considerably limits the amount of horizontal and vertical bone resorption when compared with extraction alone.15 The layer technique utilized in the described mIVAN technique shows longer term stability of the socket as it relates to the bovine graft layer, while the implant itself is placed in autogenous bone.
Implant placement in the maxillary anterior can present clinical challenges related to remaining bone on the facial aspect due to circumstances leading to extraction of the failing natural tooth. Facial undercut of the premaxilla frequently leads to dehiscence or fenestration of the tooth's root, even in the absence of periodontal or endodontic pathology. When pathological conditions lead to failure of the tooth, the thin facial (bony plate) may resorb, leaving inadequate bone for implant placement. This may be treatable at time of extraction when the immediate implant is placed; however, circumstances may warrant a delayed implant placement protocol to allow reconstruction of the socket and, depending on the socket, this may be hard tissue augmentation, soft tissue augmentation, or a combination of the two. The immediate dentoalveolar restoration technique described by da Rosa16 is an alternative procedure. In 2015, Chu et al17 addressed management of extraction sockets with labial dentoalveolar dehiscence defects, as these are commonly encountered in the maxillary anterior. Immediate implant placement simultaneous to hard tissue augmentation was discussed and a protocol and technique employing immediate implant placement, guided bone regeneration, and bone graft containment with a custom two-piece healing abutment was introduced. Authors concluded that this approach can lead to satisfactory clinical outcomes in low-smile-line patients.
Guided bone regeneration (GBR) has been used in these defects with success. GBR may be performed at the time of extraction, although the volume is often limited by the ability to achieve primary closure. Simultaneous soft-tissue augmentation is possible, allows a greater volume of hard tissue augmentation to be placed, and decreases the number of surgical treatment appointments the patient may require. Survival of the soft-tissue graft may be compromised by the graft lying on the hard tissue placed into the socket and compromised vascularization of the soft-tissue graft. To resolve these issues, the IVAN technique was developed to permit predictable simultaneous grafting of both hard and soft tissues while maintaining blood supply to the soft tissue grafting component. The authors' modification of the original IVAN soft tissue grafting utilizes a vestibular tunnel whereby the buccal soft tissue is augmented and PCTG receives additional blood supply from that area.
Various hard tissue augmentation products are clinically available for socket grafting, and bovine products have shown repeatable predictability.18 Still, these graft products demonstrate better results when combined with a resorbable membrane. Higher hard tissue graft yields have been reported with membrane usage.14,19 Socket preservation using bovine bone and porcine collagen membrane considerably limits the amount of horizontal and vertical bone resorption when compared with extraction alone.20 Due to the layer technique utilized in the mIVAN technique, a longer term stability of the socket relates to the bovine graft layer, while the implant itself is placed in autogenous bone.
Loss of the facial (bony) wall of the anterior premaxilla is a frequent occurrence with failing teeth due to endodontic, periodontal, or fracture of the tooth. This presents challenges in treatment because hard tissue reconstruction of the site needs to be performed to accommodate an implant. Additionally, this also requires soft tissue augmentation, and lack of vascularity of the facial soft tissue can compromise the results. The mIVAN technique allows for simultaneous augmentation of the hard and soft tissue while maintaining vascularity of the facial soft tissue and improving the overall grafting result. This technique may be used when the implant will be placed at the time of augmentation or when a delayed approach is required.
cone beam computerized tomography
connective tissue graft
guided bone regeneration
interpositional vascularized augmentation neogenesis
modified interpositional vascularized augmentation neogenesis
pediculated connective tissue graft
vascularized interpositional periostal connective tissue flap
No conflicts of interest are present for the authors.