Introduction

Historically, augmentation grafting to thicken buccal bone at immediate implantation (IIP) sites was done by traditional guided bone regeneration (GBR) [1–5] and involved raising soft tissue flaps, adding particulate hard tissue substitutes and covering the latter with protective membranes before flap closure and suturing. However, as we now recognize, raising flaps leads to interruption in normal local blood supply with delayed healing, variable degrees of bone resorption and possibly soft tissue recession. If possible, then, contour augmentation and managing buccal bone fenestrations and dehiscence with hard tissue grafting should be accomplished without raising soft tissue flaps. As a result, the use of flapless techniques for managing localized buccal bone defects in conjunction with IIP, especially in the aesthetic zone, has witnessed significant advancements over time [6–9]. Generally, these surgical approaches can be classified into two categories: tunneling and intrasocket GBR.

Tunneling

The subperiosteal vestibular tunnel approach is primarily used for contour augmentation procedures, targeting issues such as insufficient buccal bone thickness, labial concavities, and localized buccal fenestration defects (see also Figure 4.5 for a representative case illustration). However, it is not considered suitable for managing buccal dehiscence bone defects. On the other hand, intrasulcular tunneling involves creating tunnels within and apical to the gingival sulcus [10–12]. By using this technique, periodontists can perform various procedures such as root surface debridement or localized regenerative procedures, but the approach also can be useful in addressing labial bone and soft tissue defects during immediate implantation.

Maintaining or developing a minimum bone thickness of approximately 2 mm at the buccal socket wall of an implant, especially in the aesthetic zone, is crucial for reliably preserving soft tissue architecture over time [13, 14] and often requires a more palatal implant site development to create an adequate gap for gap grafting buccal to the implant periphery [4, 15, 16]. However, in situations where adequate palatal positioning of the implant osteotomy is not feasible, clinicians can apply tunneling strategies to manage thin buccal bone, fenestrations, and small dehiscences [17].

Strategies for addressing insufficient buccal bone thickness or fenestration defects encountered during immediate implant placement ideally should be minimally invasive and focus on preserving soft tissue architecture while still ensuring optimal IIP initial stability. The vestibular incision subperiosteal tunnel access approach (VISTA) technique was designed for this purpose [18]. Compared with using an open flap with GBR, tunneling reduces trauma and postoperative patient morbidity, preserves local blood supply, and promotes faster healing while maintaining surrounding soft tissue integrity. Once the defect is accessed, the aim is to graft the subperiosteal space created with a slowly resorbing particulate bone substitute that can provide a scaffold for new bone formation and adequate support for the overlying soft tissues [19]. While bioresorbable membranes can be used to protect the graft material, their use with VISTA tunneling is not mandatory unless mucosal lacerations have occurred during the surgery.

Prior to initiating a VISTA tunneling procedure, local anesthesia is best done remotely to avoid unnecessary perforations in the surgical field by the local anesthesia needle. The procedure is initiated using a small vertical incision in alveolar mucosa approximately 7–10 mm in length either mesial or distal to the bone defect. This becomes the entry point for the tunneling instruments. The tunnel is meticulously created beneath the periosteum, taking care to direct it accurately toward the target area. Once the tunnel has reached the desired location and been expanded sufficiently to receive the graft material, the clinician can perform the required hard‐tissue grafting with or without an added barrier material. Finally, the incision line is closed using resorbable monofilament or Vicryl (polyglactin 910) sutures, and appropriate postoperative instructions provided.

A typical IIP case handled with VISTA is presented in Figure 5.1.1. The patient’s maxillary left lateral incisor (Figure 5.1.1a) required extraction due to endodontic complications. The preoperative cone beam computed tomography (CBCT) sagittal view revealed an unfavorable labial concavity (Figure 5.1.1b), suggesting that developing an implant osteotomy could lead to a substantial buccal bone plate deficiency or fenestration. Following tooth extraction, osteotomy site preparation was completed using osseodensification drill bits [20] to optimize initial implant stability, while leaving a buccal gap to be managed with internal grafting (Figure 5.1.1c). A thin but intact buccal bone plate remained and therefore contour augmentation by tunneling was undertaken. The VISTA incision was made in the alveolar mucosa apical and mesial to the implant (Figure 5.1.1d) to allow the tunneling to be accomplished. As the quality and thickness of the mucosa and atraumatic periosteal elevation were good, xenograft particles only were used (Figure 5.1.1e) without a barrier membrane. After inserting and contouring this material to provide uniform support for the overlying soft tissues, Vicryl sutures were used to close the incision and secure the interdental papillae (Figure 5.1.1f). After 3 months of site healing (Figure 5.1.1g) and favorable soft tissue, the implant was ready for restoration. Figure 5.1.1h shows the clinical status following insertion of permanent crown.

A second case handled with VISTA is presented in Figure 5.1.2. The left lateral incisor was deemed to be hopeless (Figure 5.1.2a). To preserve soft and hard tissues, immediate implantation and peri‐implant gap grafting were performed (Figure 5.1.2b,c). However, to place the implant in a prosthetically driven position, a small fenestration occurred apically, which required immediate management. Therefore, a VISTA incision was made in the mucosal tissue distal to the implant and a subperiosteal tunnel created to access the defect. The fenestration is clearly observed from the tunnel access (Figure 5.1.2d). A collagen membrane was trimmed, shaped, and inserted over the defect and particulate xenograft material placed used under it (Figure 5.1.2e–h). The incision was closed with simple interrupted sutures, and a prosthetic abutment connected to the implant (Figure 5.1.2i), followed by the insertion of an immediate temporary crown (Figure 5.1.2j). Finally, the favorable soft tissue condition before final crown insertion, final restoration, and radiographic image after insertion are shown in Figure 5.1.2k–m.

Intrasocket Guided Bone Regeneration

If pre‐extraction dehiscence is detected in diagnostic CBCT images (i.e. type II sockets: buccal soft tissue intact but buccal plate partially missing following extraction of the tooth [21]), an intrasocket approach can be taken to achieve flapless GBR. To accomplish this, after implant insertion, a cross‐linked collagen membrane is trimmed to fit and positioned within the socket to cover the bone defect. The space between the implant fixture and membrane was filled with a xenogeneic particulate bone substitute graft material. Rather than using a stock healing abutment, a customized healing abutment or provisional restoration can lead to improved outcomes [22–24]. If there is a need to improve the gingival phenotype, a free connective tissue graft or volume‐stable collagen matrix can be inserted between the collagen membrane and overlying gingiva. Using this intrasocket approach is cost efficient and time‐saving. The disadvantages could be limited visibility, limited access for graft and membrane placement, and higher skill requirements.

A sample case is depicted in Figure 5.1.3. The patient’s pretreatment CBCT revealed an oblique root fracture and loss of approximately one‐third of the buccal cortex (Figure 5.1.3a). The socket was designated as type IIA [25], there being absence of the coronal one‐third of buccal bone plate 5–6 mm from the free gingival margin (Figure 5.1.3b,c). The implant osteotomy was established in a prosthetically favorable orientation using osseodensification burs (Figure 5.1.3d) and the implant inserted (Figure 5.1.3e). A collagen barrier was appropriately trimmed (Figure 5.1.3f) and inserted under the mucoperiosteum buccally to cover the dehiscence (Figure 5.1.3g). Particulate xenograft material was inserted into the gap between the membrane and the implant surface (Figure 5.1.3h) and packed with moderate pressure to ensure augmentation of the buccal socket wall by about 2 mm (Figure 5.1.3i). Finally, a transitional crown was added to support the peri‐implant soft tissues (Figure 5.1.3j,k). Three months later, the implant was ready for fabrication of the permanent crown (Figure 5.1.3l), which is shown in Figure 5.1.3m. A follow‐up radiograph of the treatment after 5 years in function is shown in Figure 5.1.3n.

A second example of an intrasocket GBR shows a patient where both buccal bone and buccal soft tissue grafting were needed for optimal treatment. The patient’s maxillary right central incisor had developed significant apical root resorption (Figure 5.1.4a) located approximately 9 mm from the gingival margin. An odd whitish discoloration of the buccal gingiva was present at this location (Figure 5.1.4b). There was slight mid‐facial gingival recession creating a discrepancy in the gingival margin compared with the left central incisor. CBCT imaging in the sagittal plane suggested the socket to be a type II‐B and displayed partial disintegration of the buccal plate (Figure 5.1.4c).

Treatment began with the removal of the tooth root which revealed a great deal of cement‐like material remaining in the socket (Figure 5.1.4d). This was likely the origin of the white area seen through the alveolar mucosa in the clinical photo. After removing most of this foreign material, the apically deficient buccal plate could be seen (Figure 5.1.4e). After meticulous degranulation, the implant osteotomy was prepared with osseodensification burs directed palatally and the implant inserted (Figure 5.1.4f). A collagen barrier membrane was carefully trimmed to ensure coverage of the bone defect and inserted buccally (Figure 5.1.4g), leaving a healthy‐sized space between it and the implant periphery which was then packed with xenograft material (Figure 5.1.4h). A connective tissue graft was removed from the right palate and inserted buccally under the soft tissues but covering the barrier material (Figure 5.1.4i). Two sutures were used to secure this graft (Figure 5.1.4j) and a transitional crown connected to the implant (Figure 5.1.4k). After 3 months of undisturbed healing, a new CBCT series confirmed that the implant had been well positioned and that the buccal bone had thickened with the previous deficiency totally eliminated by the grafting technique employed (Figure 5.1.4l). By this time, the discrepancy of the gingival architecture between the two incisors had been eliminated with the soft tissue graft (Figure 5.1.4m).

The Ice Cream Cone Technique

The “ice cream cone technique” can be considered a modification of intrasocket GBR and was pioneered by Tarnow et al. [21, 26] to address buccal dehiscences at IIP sites. It involves trimming a collagen membrane into an ice cream cone shape and inserting the cone portion under the buccal soft tissues to isolate the dehiscence, while the contoured ice cream portion of the membrane is used to cover the grafted gap and implant. Its disadvantage is that it requires implant submergence during osseointegration, thereby eliminating the valuable contribution of customized healing abutments or transitional restorations in holding pre‐extraction gingival contours and supporting the interdental papillae during site healing. An example of a patient treated this way is a young woman who had suffered a traumatic injury to both maxillary central incisors (Figure 5.1.5a). Periodontal probing revealed an 8‐mm pocket buccal to right incisor with 5–6 mm pocket depths on both teeth palatally. There was a swelling on the buccodistal of the right incisor, suggestive of abscess formation. CBCT revealed the tooth sockets to be type II‐A [25] and clearly indicated horizontal root fractures of both teeth (Figure 5.1.5b). Both incisors were removed without raising a mucoperiosteal flap (Figure 5.1.5c), after which a narrow dehiscence defect was noted in the buccal socket wall of the right incisor. A cross‐linked collagen membrane was trimmed in the ice cream cone format (Figure 5.1.5d) to cover the buccal dehiscence defect. Implant site preparation was carried out using standard implant drills followed by immediate placement of two implants while leaving adequate space for gap grafting with particulate xenograft after insertion of the shaped collagen membrane (Figure 5.1.5e). The exposed ice cream scoop segment of the barrier (Figure 5.1.5f) was folded over the grafted right implant site, while a small piece of barrier was stabilized over the left implant and the soft tissues sutured (Figure 5.1.5g). Despite the absence of healing abutments or transitional crowns, the soft tissues healed favorably (Figure 5.1.5h,i). Post‐treatment CBCT in the sagittal plane at 3 months showed complete regeneration of the right buccal plate with a buccal thickness of approximately 2 mm. The buccal plate at the left was intact but somewhat thinner compared with the right side (Figure 5.1.5j). A tissue punch was used at re‐entry and a midline frenectomy performed (Figure 5.1.5k) and, after a further few weeks for soft tissue healing, the implants were ready to be restored (Figure 5.1.5l,m). The final restorations on the day of insertion are shown in Figure 5.1.4n.

To provide extra support for healing of the papillae this original ice cream cone technique can be slightly modified by widening the ice cream scoop portion of the membrane to approximately twice the width of the surgical site adding “wings”. After implant placement, the cone‐shaped part of the membrane is positioned, as usual, within the socket to cover the dehiscence defect and the grafting of buccal bone completed. Next, the shape of the widened ice cream scoop portion is fitted by making two curved incisions to create mesial and distal wings following the curvatures of the adjacent tooth crowns. These wings are then folded towards the center of the site and teased under both papillae.

The final example demonstrates this modified ice cream cone intrasocket GBR approach. The patient’s endodontically treated right central incisor had fractured at the gingival margin (Figure 5.1.6a) and a diagnostic CBCT series revealed a large fenestration in the apical third of the buccal plate (Figure 5.1.6b). To complicate matters, the buccal plate fractured during the extraction process. Therefore, the decision was made to perform the modified ice cream cone technique of intrasocket GBR. Having removed the root, an appropriate osteotomy was created using osseodensification burs (Figure 5.1.6c), as prescribed by the manufacturer in counterclockwise direction [20], and an implant installed (Figure 5.1.6d). Next, the collagen membrane was trimmed as a modified ice cream cone leaving the diameter of the ice cream scoop portion twice the width of the edentulous central incisor space (T‐6e). The cone portion of the barrier was inserted under the buccal soft tissues to cover the bone defect, after which the peri‐implant buccal gap were packed with xenogeneic bone substitute (Figure 5.1.6f). Next, the mesial and distal sides of the ice cream scoop portion were trimmed to conform to the proximal contours of the adjacent teeth forming wings (Figure 5.1.6g,h). This was followed by delicate 90‐degree bending of each wing to allow insertion under its adjacent papilla (Figure 5.1.6i). Figure 5.1.6j shows the supportive role of the collagen membrane wings in bolstering both interdental papillae. Figure 5.1.6k is an occlusal view showing a complete seal of the socket, with the overlapping wings meant to enhance support and thicken the two papillae.

The collagen membrane was secured using one suture with its knot positioned to provide support to the interdental papillae (Figure 5.1.6l,m). Figures 5.1.6n,o show favorable soft tissue conditions and good maintenance of the buccopalatal ridge anatomy after 3 months. Figure 5.1.6p,q shows the clinical and radiographic status of the restored site after 2 years of function.

The advantage of the modified ice cream cone technique is enhanced support and thickening for the interdental papillae contributing to esthetic outcomes, particularly in cases where the addition of an immediate transitional restoration is not possible. However, it is essential to recognize that the technique still shares the limitations of the original approach, including potential challenges in membrane placement, its suitability primarily for simple dehiscence defects, and the need for submerged implant site healing and later re‐entry surgery.

Conclusion

Fenestrations of the buccal bone can be routinely managed with any of the techniques presented in this chapter, but the most efficient ways would be soft tissue tunneling with subperiosteal bone augmentation or the original intrasocket method using a collagen membrane to cover the bone defect and added bone graft material. As the implant is allowed non‐submerged healing, immediate provisionalization is also feasible limiting the period of edentulism and satisfying patient concerns about esthetics. IIPs placed at sites with buccal dehiscence defects may be better managed with the original or modified ice cream cone barrier techniques including submerged implant integration healing. Alternatively, these larger bone defects can be managed with the immediate dentoalveolar restoration technique, which is the subject of Chapter 5.3 of this book. Immediate dentoalveolar restoration does require considerably more surgical experience, as it involves transplantation of tuberosity block grafts at the time of the IIP intervention.