**3.1 Connective tissue graft harvesting (CTG)**

The harvesting technique of the CTG has a direct influence on the graft dimension, histological composition, harvesting complications, morbidity, healing dynamics of

**Figure 4.** *Connective tissue graft.*

the donor site, healing dynamics of the recipient site, and outcome of the grafting procedure. The ideal technique should enable the maximum volume and quality of the graft to be harvested, while concurrently limiting trauma, postoperative morbidity, and possible complications connected with CTG harvesting [43]. A variety number of techniques have been described in the literature for connective tissue graft harvesting. All the techniques can be divided into two groups—(1) connective tissue harvesting with the preparation of the primary flap (offend referred to as subepithelial connective tissue graft, sCTG) and (2) free gingival graft harvesting with extraoral deepithelization. The first group can be further subdivided into free CTG or pedicle CTG depending if the CTG is completely dissected or remains attached by one side of the palatal soft tissue [26, 40, 42–45].

The palate is the most frequent site donor site for CTG or FGG harvesting [40]. Histologically, it is composed of different layers—the most superficial epithelial layer, covering a dense connective tissue layer (lamina propria). The submucosal layer is located below the lamina propria and above the periosteum, containing fatty and glandular tissue. Preferably, the CTG should consist only or mostly of the lamina propria layer, with little or no submucosa [26, 46]. Fatty and glandular tissue can hinder or slow the revascularization of the graft after its transplantation [31]. Furthermore, they can be responsible for the increased shrinkage rate of the CTG during healing, influencing the outcome of the grafting procedure [40, 47, 48].

Palatal soft tissue thickness differs greatly among the various areas of the palate and among individuals [49–51].

Limited data in the literature suggest that patients with thick palatal soft tissue have increased thickness mainly of the submucosal layer while the dimensions of lamina propria remain unchanged [49]. It could be hypothesized that CTG harvesting with the primary flap techniques in thick palatal soft tissue would always result in a graft composed of a lower percentage of lamina propria. The only layer that would have increased share in graft thickness would be the submucosal layer [49].

In the case of thin palatal soft tissue, there is not enough connective tissue thickness to prepare the primary flap and the CTG. The result of CTG harvesting with the primary flap in those situations can lead either to (1) primary flap necrosis if the primary flap is prepared to thin in order to increase the composition of the lamina propria inside CTG, or (2) CTG with a decreased thickness and composition of lamina propria which can result in the improper outcome of the harvesting procedure [48].

To overcome the aforementioned drawbacks, a new harvesting procedure was described—harvesting of an FGG and afterward, intra- or extra-oral de-epithelization of the FGG. As a consequence of the de-epithelization, the epitel layer is removed and the FGG graft is converted into CTG. With this harvesting procedure, the most valuable tissue (lamina propria) is almost completely inside the graft regardless of the initial thickness of the palatal soft tissue. In contrast, when the primary flap is used, a varying percentage of the lamina propria remains unutilized, attached to the inner side of the primary flap [40, 49, 52]. Furthermore, CTG obtained with the new harvesting procedure (de-epithelized FGG) is firmer and easier to manage during the grafting procedure with less variations in compositions among different CTG [48, 49].

The main disadvantage of the de-epithelized FGG procedure is the secondary intention healing of the donor site resulting in a slower healing process related to a higher percentage of complications linked to the donor site (pain and bleeding). Patients who underwent CTG graft harvesting experienced a lower incidence of donor site pain in the early postoperative period compared to FGG graft harvesting patients (**Table 1**) [49, 52–55].


#### **Table 1.**

*Advantages and disadvantages of CTG harvesting techniques: CTG with the primary flap and de-epithelized CTG.*
