**6. Substitutional soft tissue grafts**

Although the results of PIS grafting with substitutional grafts, at the present are inferior to the results obtained after autogenous soft tissue grafting [5, 8, 65, 66, 93, 99], the absence of the donor site makes this treatment modality appealing to the patient and practitioners, as well [26, 42, 100].

The elimination of the harvesting procedure [25, 65] will lead to the reduction of surgical time [65], simplify the surgical procedure [42, 100], decrease the patient morbidity [26, 42, 65, 93], allow the unlimited supply of the soft tissue graft [26, 101, 102], and increase patient acceptance for the procedure [42, 65, 100, 103].

The augmentation procedure with substitutional soft tissue grafts will result in PIS with perfect color and texture blending to the adjacent soft tissue [65, 101].

Two types of substitutional grafts are available—xenogenic and allogeneic soft tissue grafts. Both of the grafts can be used for augmenting the volume and the width of keratinized mucosal band [25, 26, 65, 93, 99, 104].

The substitutional grafts are deprived of vital cells. During the manufacturing procedure, cells and antigenic components are removed, preserving only the extracellular matrix consisting mainly of collagen and elastin fibers. The three-dimensional structures of the aforementioned scaffold will promote fibroblast and keratinocyte migration and vascular ingrowth from the surrounding tissue [105–107]. This will result in an excellent color match since the keratinocytes are derived from the surrounding tissue. Nevertheless, compared to autogenous soft tissue grafts, they do not possess the ability to promote keratinization, limiting their application for increasing the width of KM [105, 106]. To overcome this drawback, a combination of an FGG graft with reduced apico-coronal dimensions to 2 mm and an XCM was proposed [6].

When used to augment PIS thickness, substitutional grafts are less resistant to compression of the overlaying flap compared to CTG. Loss of the initial volume of the substitutional graft can lead to the compromised outcome of the grafting procedure. To overcome this drawback, a volume stable collagen matrix was developed [105]. As a result of the cross-linking process of the collagen fibers, the collagen matrix becomes more volume stable and prone to withstand soft-tissue pressure [108, 109]. At the moment there is a lack of literature on the long-term stability of augmented PIS with the substitutional grafts (**Figures 39–66**) [105].

**Figure 39.** *Initial situation—Lateral view.*

**Figure 40.** *Initial situation.*

**Figure 41.** *Surgical stent.*

**Figure 42.** *Dehiscence bone defects around implant 16 and 15.*

#### **Figure 43.**

*GBR: A composite bone graft was used consisting of 50% autogenous and 50% xenogenic graft. The bone graft was applied in two layers—The internal layer which is covering the exposed implant surface, is made out of autogenous bone and the external layer is consisting of a xenogenic bone graft.*

**Figure 44.** *GBR: Native collagen membrane stabilized with resorbable sutures.*

#### **Figure 45.**

*Suturing in three layers;(1) palatal-apical position—Mattress sutures for membrane stabilization, (2) buccalapical—Mattress sutures for initial closing of the flap, and (3) bucco-coronal—Simple interrupted suture for the final closure of the flap.*

#### **Figure 46.**

*Four months after the GBR, the palatal displacement of the mucogingival line is evident. Occlusal view.*

*Peri-Implant Soft Tissue Augmentation DOI: http://dx.doi.org/10.5772/intechopen.101336*

**Figure 48.** *The surgical stent was used to determine the dimensions of the flap.*

#### **Figure 49.**

*The flap incision is made not at the mucogingival junction but 4 mm within the keratinized mucosa, therefore the buccal split-thickness flap will include a band of keratinized mucosa which is 4 mm wide.*

#### **Figure 50.**

*Finalized preparation of the buccal split-thickness flap. The most coronal part of the partial-thickness flap consists of keratinized mucosa.*

#### **Figure 51.**

*Apically positioned flap—Stabilization of the buccal partial-thickness flap in the new apical position. The exposed periosteal surface is completely surrounded by keratinized mucosa.*

**Figure 52.** *The exposed periosteal surface is covered with xenogenic collagen matrix (Mucoderm, Botiss gmbh, Berlin).*

#### **Figure 53.**

*Healing two months after the keratinized mucosa widening procedure. The gain of the keratinized mucosa is evident but the thickness of the gained tissue is unsatisfactory. Occlusal view.*

#### **Figure 54.**

*Healing two months after the keratinized mucosa widening procedure. The gain of the keratinized mucosa is evident but the thickness of the gained tissue is unsatisfactory. Lateral view.*

#### **Figure 55.**

*During the implant uncovering procedure, a primary flap was prepared on the palatal side. The minimal thickness of 1.5 mm of the primary flap was respected, and the connective tissue was exposed.*

#### **Figure 56.**

*Mesial, distal and apical incisions were made inside the connective tissue graft in order to completely dissect the CTG from the rest of the adjacent soft tissue.*

**Figure 57.** *The CTG is completely dissected from the rest of the adjacent soft tissue.*

#### **Figure 58.**

*On the left: CTG harvested from the palate (the harvesting procedure was displayed on the previous pictures), on the right additional CTG harvested from the tuberosity on the same side.*

#### **Figure 60.** *Appearance of the regenerated bone on the buccal side of the implants.*

**Figure 61.** *Both of the CTG grafts were stabilized with sutures to the buccal flap.*

**Figure 63.** *Final suturing of the flap.*

#### **Figure 64.**

*After 2 months of healing adequate quantity (soft tissue thickness) and quality (width of keratinized mucosa) of soft tissue surrounding the healing abutments.*

**Figure 65.** *Screw retained abutments.*

**Figure 66.** *Three units screw-retained bridge.*
