To Preserve/Improve Buccal Contour Convexity

Preservation of peri‐implant buccal contours is recommended to simulate root prominences, to help reduce the incidence of food retention buccally, and to maximize esthetic appearance. Cases with the following criteria are more prone to develop buccal contour collapse following IIP and seem to benefit from contour preservation at the level of hard tissue zone: (i) thin buccal socket wall (< 1 mm); (ii) buccal bone dehiscence; (iii) where the original tooth is outside its bone envelope; and (iv) where basal bone width is less than that of alveolar process (Table 6.1) [27].

Generally, CTG or guided bone regeneration (GBR) are suggested to prevent buccal contour collapse or to augment buccal contour at the level of hard tissue zone. De Bruyckere et al. [28] conducted a randomized controlled clinical study comparing stability of buccal contours 1 year following either GBR using bovine bone xenograft combined with collagen membranes or just CTGs around single implants. Their results showed similar outcomes. The addition of CTG is also helpful in improving emergence profile of the implant crown without risk of progressive mucosal recession [29]. This is especially the case in sites with thin gingival phenotype.

To Prevent Peri‐Implant Soft Tissue Dehiscence/Deficiency

The risk of soft tissue recession following IIP is elevated in cases with thin gingival phenotype, less than 0.5 mm buccal bone thickness [30], and buccally positioned implants [31]. The horizontal distance between the buccal aspect of the implant transmucosal component and buccal soft tissues also affects marginal soft tissue thickness [32]. An over‐contoured restoration can cause thinning of marginal soft tissue and lead to mucosal recession, especially in cases with thin gingival phenotype. Conversely, a concave contour of the transmucosal component at the subcritical zone allows supracrestal soft tissue ingrowth and thickening during the healing process [33]. Establishment of horizontal marginal mucosal thickness of at least 2 mm has been recommended for long‐term stability. Otherwise, metal shadow can be the consequence of inadequate mucosal thickness [34].

A hopeless tooth with mild to moderate gingival recession is no longer considered as a contraindication for IIP, since the initial unfavorable position of the gingival margin can be compensated by coronal advancement of the flap [29] or exposing a part of a CTG coronal to the marginal mucosa.

The width of keratinized mucosa (KM) around dental implants is often recommended to be ≥ 2 mm but if not, as with the natural dentition, its absence in patients whose teeth are well‐maintained and who are compliant may not be crucial [35]. However, keratinized peri‐implant tissue width should be considered for enhancement if there is peri‐implant inflammation/bleeding, with an associated shallow vestibule or if the patient experiences pain during oral hygiene performance at sites with inadequate amounts of KM (< 2 mm). The results of a systematic review indicated that KM augmentation results in a significant reduction in bleeding on probing, plaque index, gingival index, probing depth, and marginal bone levels [36]. Finally, establishment of an attached KM in the supracrestal zone guarantees the quality of the soft tissue seal around the implant and prevents transmission of toxic products from oral cavity to the crestal bone tissue, thereby ensuring long‐term stability of implant osseointegration.

To Preserve/Improve Interproximal Papilla Thickness/Height

In the natural dentition, the supra‐alveolar collagen fiber apparatus which attaches to the teeth maintains the architecture of interdental papillae [37]. Extraction of a single tooth results in the loss of half of the papillary supra‐alveolar fibers extending from the adjacent teeth. However, papillae still can be preserved here since fibers exiting from the neighboring teeth can preserve the papilla tips. With dental implants, the parallel orientation of the supracrestal collagen fibers provides much weaker support for papillae. Not surprisingly then, papilla tips dropconsiderably when two adjacent teeth are replaced with IIPs. Therefore, attempts to preserve the inter‐implant papilla height/thickness should be considered with IIP in the esthetic zone [38].

Moreover, loss of interproximal periodontal support or previous papilla‐raising flap surgery, frequently causes papilla deficiencies. Extraction of a hopeless tooth with deficient neighboring papillae further accentuates these deficiencies. Minimal blood supply and difficult access to the small, narrow, and fragile papillary tissue makes any papilla augmentation procedure unpredictable and often unsuccessful. That’s why reconstruction of peri‐implant papillae remains one of the most challenging issues in implant dentistry [39].

We suggest adjunctive soft tissue grafting in cases susceptible to loss of interproximal papillae in the esthetic zone (i.e. thin and narrow papillae or those between two adjacent implants, especially when two implants are too close to each other) [21, 23, 40, 41, 42]. Soft tissue grafting at the base of papillae is also indicated when there is a risk of exposure of prosthetic margins of adjacent teeth/implants following extraction of a hopeless tooth. For symmetrical reasons, papilla “augmentation” is only indicated when the papilla loss is limited to the area of the tooth to be extracted and is possible using pedicle flaps (Table 6.1) [43].

To Minimize the Need for Buccal Flap Advancement

Occasionally, buccal and palatal bone defects are so wide and deep as to need advanced ridge augmentation, coverage of implant shoulders, and membrane fixation at the time of IIP. However, this procedure poses some challenges in terms of lack of adequate quantity of soft tissue over the socket entrance. This is especially a concern in the esthetic zone, where “major buccal flap advancement” results in severe disturbances in soft tissue texture and color, lack of KM, and creation of a shallow vestibule leading to an unhealthy and unaesthetic appearance. Using pedicle palatal flaps [43] in conjunction with IIP and ridge augmentation procedures can be helpful here avoiding the need for buccal flap advancement and to hasten the duration of treatment. It is important to note that this procedure is only indicated for those cases where adequate native bone is still available to place the implant in the correct three‐dimensional prosthetically‐driven position with adequate primary stability. Otherwise, IIP is contraindicated (Table 6.1).

Scarf‐Connective Tissue Graft

Scarf‐CTG is often combined with provisional prosthesis to improve and maintain the contour of the supracrestal marginal soft tissue and to prevent shrinkage of the socket collar with mucosal recession. Following flapless extraction, IIP and gap filling, a semilunar CTG with a minimal thickness of 1.5 mm is adapted and fixed in the subcritical area [26], which is the peri‐implant zone between the the prosthetic platform of the implant and the supracrestal mucosa. The CTG should extend from mesial line angle to distal line angle of the socket to support the interproximal papillae. The original technique used a subepithelial CTG rather than a de‐epithelialized CTG to favor the “C”‐shape bending. Based on experiences of the present author, the de‐epithelialized CTG is advantageous in terms of stability and manipulation (Figure 6.2). To improve graft revascularization, after placement it should be secured to the overlying mucosa using 7.0 sutures, although this was not mentioned in the original publication [44].

Some clinicians prefer to remove the internal epithelium of the gingival sulcus with a scalpel/bur/curette before placing a CTG to provide a vascularized recipient bed for the graft and to prevent development of a marginal groove between the mucosa and the graft (Figure 6.3). Others believe that this is not essential for success and is indeed risky in such a loose and thin area. This is especially a concern in cases with thin gingival phenotype where accidental mucosal damage could lead to exposure of the graft and ultimate color mismatch during healing period.

Scarf‐Connective Tissue Graft versus Coronally Advanced Flap/Tunnel Technique plus Connective Tissue Graft

Although a scarf‐CTG is a less‐invasive surgical technique, it is not useful for contour preservation at the hard tissue zone. This technique is indicated if the gingival phenotype is thin and the buccal bone is thick (> 1 mm). Otherwise, TUN + CTG or CAF + CTG are recommended. In fact, TUN + CTG and CAF + CTG are effective in preserving/improving contours in both the supra‐crestal soft tissue and hard tissue zones. These two techniques are also more appropriate for management of gingival recession already existing around the tooth to be extracted as, unlike with scarf‐CTG, both CAF + CTG and TUN + CTG require the flap elevation needed for flap advancement (Table 6.1).

Tunnel Technique plus Connective Tissue Graft

The advantages of TUN + CTG compared with CAF + CTG include soft tissue elevation without papilla detachment, thereby reducing the risk of papilla shortening. In addition, risk of postoperative scar tissue formation is reduced, since there is no visible incision. However, the use of specifically designed instruments is mandatory to minimize the risk of flap perforation or papilla detachment during tunnel preparation (Figure 6.4). The “modified” tunneling technique allows enhanced access to the buccal contour and graft insertion through an apical vertical incision (Figure 6.5) [46]. This approach is particularly helpful for cases with very thin gingival phenotype, where there is an increased risk of mucosal rupture during tunnel preparation and graft insertion. We suggest that TUN + CTG as a way to increase width of KM, and with this in mind, we suggest leaving part of the CTG coronally exposed for transformation into KM (Figure 6.6). This slightly exposed part of CTG usually does not undergo necrosis. For this purpose, at least 5 mm of the graft should be covered by the flap apically and laterally and with about 2 mm of the CTG exposed coronally.

Originally, TUN + CTG was designed for management of “multiple” adjacent tooth recession defects. TUN + CTG for single IIPs needs to extend one tooth mesial and one distal, although sites with wide KT or scarred fibrotic tissue (as a consequence of previous surgery) may need more extension. Insufficient tunneling could leave tension and cause damage to the tunneled flap margin during graft insertion. Furthermore, excessive pressure created by the graft to the overlying tissue might disturb blood supply and cause necrosis, especially where the gingival phenotype is thin.

A late complication of TUN + CTG could be the apical displacement of the graft under the alveolar mucosa [47] resulting in a bulge‐shaped, unaesthetic appearance buccally (Figure 6.7) and failure to produce a thick gingival margin. This complication is more relevant in cases with a wide band of KM. To avoid it, we suggest: (i) increasing the lateral extension of the tunnel; and (ii) securing the graft not only to each adjacent papilla, but also to the mid‐buccal keratinized area using a horizontal mattress suture (Figure 6.8).

We suggest packing peri‐implant buccal gaps with bone graft (allograft or xenograft) before tunnel preparation, if the buccal bone is very thin. This will avoid risk of buccal plate fracture during the tunneling/CTG procedure.

Coronally Advanced Flap plus Connective Tissue Graft

Coronally advanced flap plus CTG is a well‐documented procedure for contour preservation around immediately placed implants [29, 42]. To maximize success, the following technical notes can be helpful. Firstly, CAF + CTG around single implants is possible with an envelope flap involving at least two adjacent teeth (Figure 6.9). In some situations, however, at least one vertical releasing incision may be necessary to achieve adequate access for flap advancement. To minimize risk of scar tissue formation with this vertical incision, it is recommended to use a beveled incision instead of a full‐thickness perpendicular incision (Figure 6.10). Next, delicate and complete de‐epithelialization of existing papillae is crucial to prevent healing by secondary intension and scar tissue formation (Figure 6.11). If at all possible, the graft should be sutured to the underlying periosteal bed and base of the papillae instead of to the flap as this enhances graft stability. The optimal thickness of the CTG is 1.5 mm (Figure 6.9d). We also recommend that the graft be positioned and secured at the level of the ideal position of the future gingival margin to ensure its optimal final thickness. From the apical direction, a CTG needs to be extended 2–3 mm over the bone crest. In terms of mesiodistal dimension, the graft should cover both mesial and distal papillae (Figure 6.9e) to facilitate its fixation and to enhance papilla thickness and height.

When to Select Coronally Advanced Flap plus Connective Tissue Graft or Tunnel Technique plus Connective Tissue Graft?

We suggest using TUN + CTG (including its modified approach) rather than CAF + CTG in the following situations: (i) to increase KM (Figure 6.6); (ii) where there is risk of papilla loss; that is, thin/narrow papillae or two adjacent implants (Figure 6.12); and (iii) where there is an adjacent tooth‐ or implant‐supported prosthetic crown (Figure 6.13), particularly in patients with high esthetic demands. On the other hand, we prefer CAF + CTG in the following situations: (i) sites with a wide band of keratinized tissue and/or scarred soft tissue (due to the technical sensitivity in using a tunnel preparation) (Figure 6.9); (ii) if direct access to the periapical region is necessary to improve visibility and ensure complete debridement of existing pathology or to graft/augment bone defects; and (iii) where simultaneous crown lengthening of adjacent teeth is planned (Figure 6.14).

Rotated Pedicle Palatal Flap (RPPF)

Several studies have reported the RPPF and its modifications as a predictable and valuable treatment to achieve primary soft tissue coverage and to improve soft tissue (papilla) height at single implants in anterior maxilla [48–52]. This superiority is owing to the preservation of the blood supply of the rotated graft which facilitates its re‐vascularization, even if left exposed. Furthermore, some researchers hypothesized that RPPF might be beneficial in terms of long‐term volume stability [48, 53]. We suggest this technique to cover sockets when advanced hard tissue augmentation is performed simultaneous with single IIPs. This compensates for the lack of soft tissue over the extraction socket and enables soft tissue coverage without the necessity of buccal flap advancement which is especially crucial in the esthetic zone (Figure 6.15). We also recommend this technique for augmenting papillae in the esthetic zone. In contrast to a free CTG, RPPF is a more predictable surgical approach for papilla augmentation because of its vascular supply (Table 6.1).

Following the placement of a single IIP and precise debridement of the two adjacent tooth surfaces, a buccal full‐thickness flap including the buccal papillae is elevated. From the palatal aspect, a long sulcular full‐thickness flap is elevated. A new blade is then used to perform a second incision to bisect the palatal flap. To keep greater thickness of the pedicle flap and improve its mechanical stability, the subepithelial flap should include the underlying periosteum. The width of a RPPF should be decided based on the mesiodistal dimension of the edentulous area. Its length should be calculated to achieve complete coverage of the buccopalatal dimension of the socket with extension to at least 5 mm over its facial aspect. For non‐molar sites, it is generally preferred to harvest the pedicle flap from the distal palate and rotate it to the mesial side for several reasons: (i) the quality of tissue in distal palate; (ii) the lack of anatomical limitations (e.g. rugae); and (iii) improved clinical access (lack of palatal vault). The margin of the rotated flap is secured to the periosteum located at the most apical extension of the buccal flap. Finally, the buccal and palatal flaps are repositioned and sutured to each other. Owing to the anatomic limitations and risk of damage to the greater palatine artery, the application of this technique is limited to single implants.