div epub:type=”chapter” role=”doc-chapter”>
S. Nares (ed.)Advances in Periodontal Surgerydoi.org/10.1007/978-3-030-12310-9_10
10. Rationale for Gingival Tissue Augmentation and Vestibuloplasty Around Teeth and Dental Implants
Keratinized tissueFree gingival graftAlveolar ridgePeriodontal biotypeVestibuloplastySurgical graftsPeri-implant mucosa
10.1 The Dilemma of Whether or Not to Augment the Band of Keratinized Tissue
What circumstances require an increased zone of KT, or is KT important? 
Conclusions/Response: “Authors have noted the limitation of recent clinical studies, randomized clinical trials (RCTs), and systemic reviews to answer this question. However, clinical observations would suggest that sites with minimal or no gingiva and associated with restorative margins are more prone to gingival recession and inflammation. Thus, gingival augmentation is indicated for sites with minimal or no gingiva that are receiving intracrevicular restorative margins based on clinical observations (SORT [Strength-of-Recommendation Taxonomy criteria] level B [inconsistent or limited-quality patient-oriented evidence])” .
What is the ideal thickness of an autogenous gingival graft? Is a thick autogenous gingival graft more effective than a thin autogenous gingival graft? 
Conclusions/Response: “A palatal graft should be ≥1-mm thick. Thin grafts tend to result in more esthetic outcomes, whereas thick grafts provide more functional resistance. Thick grafts tend to follow significant primary contraction, whereas thin grafts are more prone to secondary contraction. The type of biotype may play an important role in maintaining optimal periodontal health, but disagreements exist among clinicians when describing the types of biotypes (SORT level B [inconsistent or limited-quality patient-oriented evidence])” .
What are the alternatives to autogenous gingival grafting to increase the zone of attached gingiva? 
Conclusions/Response: “Modified apically positioned flap may be an effective technique in increasing the apico-coronal dimension of the KT and attached gingiva without donor areas or use of commercial products”….“alternative methods and materials (i.e., acellular dermal matrix grafts, extracellular matrix, xenogenic porcine bilayer collagen matrix and living cellular construct) have been shown to provide enough attached KT to correct areas lacking or with minimal gingiva (<2 mm) around teeth in short-term and in small–sample size studies. The advantages of these approaches are avoidance of donor areas and unlimited supply. However, long-term follow-up studies and RCTs should be conducted to strengthen this treatment approach (SORT level C [consensus, disease-oriented evidence, usual practice, expert opinion, or case series for studies of diagnosis, treatment, prevention, or screening])” .
Does orthodontic intervention affect soft tissue health and dimensions? 
Conclusions/Response: “Historic clinical observations and recommendations can be referenced to answer this question. The direction of the tooth movement and the bucco-lingual thickness of the gingiva play important roles in soft tissue alteration during orthodontic treatment. There is a higher probability of recession during tooth movement in areas with <2 mm of gingiva. Gingival augmentation can be indicated before the initiation of orthodontic treatment in areas with <2 mm (SORT level C [consensus, disease-oriented evidence, usual practice, expert opinion, or case series for studies of diagnosis, treatment, prevention, or screening])” .
What is the patient-reported outcome for minimal KT compared with that for an enhanced zone of KT? 
Conclusions/Response: “Alternative methods and materials appear to result in less patient discomfort after gingival augmentation procedures when compared with FGG. They have also shown to result in better color and texture match to surrounding tissue when compared with FGG. However, study investigators need to standardize how they collect the patient-reported outcomes so the obtained results can be compared with other studies (SORT level C [consensus, disease-oriented evidence, usual practice, expert opinion, or case series for studies of diagnosis, treatment, prevention, or screening])” .
Furthermore, recent clinical long-term data (18–35 years) by Agudio et al. [5, 6] reported in several practice-based studies comprising of patients with high standards of oral hygiene shed light on the importance of gingival/KT augmentation. In the first study, it was found that teeth with single recession defects and lacking a minimum KT band of 2 mm undergoing gingival augmentation (via free gingival graft-based procedures) may display a phenomenon called “creeping attachment” (i.e., a coronal shift of the gingival margin), leading to noteworthy gingival recession reduction 10–27 years after treatment . In the second publication, the authors confirmed that gingival augmentation might influence the biologic remodeling of periodontal dimensions associated with the aging process, as well as that use of free gingival grafts can produce more beneficial KT band proportions and reduce gingival recession depth . The second study also reported that some degree of shrinkage will occur, thus “the corono-apical dimension of the graft should be calculated on the basis of the KT width of adjacent untreated teeth plus an additional 1.00–1.50 mm considering an estimated tissue contraction during the early healing, and long follow-up period” . As a result, the authors suggested that clinicians prepare grafts with an additional apical dimension of 1.00–1.50 mm of the mucogingival junction of adjacent untreated teeth .
Similar to the concepts established for natural teeth, current evidence (even though minimal) clearly indicates the positive gains of increasing the KT band at dental implant sites [7, 8]. Improvements in KT width and thickness at periodontal and peri-implant sites may be essential to create a “mechanical/physical and biological epithelial barrier” that will give protection to peri-implant structures in view of cytokine, chemokine, and antimicrobial peptide production (i.e., interleukin-1α, interleukin-1β, interleukin-6, interleukin-8, and tumor necrosis factor-α) in response to toothbrushing trauma and dental biofilm [8, 9]. In general terms, it has been shown that an increase in KT in areas of elastic peri-implant mucosa by gingival augmentation procedures (i.e., free gingival graft and apically positioned flap) may promote the formation of a firm KT band and thus reduce the probability for gingival recession [7, 8].
Consequently, the above reported studies and reviews support the key role of KT dimensions in the maintenance of the gingival margin stability around natural teeth and dental implants. In addition, these aspects rationally indicate that such grafting procedures will promote a “biotype modification” (i.e., KT width and thickness gain) and should be considered when deemed necessary.
10.2 Surgical Procedures Used for Gingival Augmentation Around Natural Teeth and Dental Implants
As stated above, accumulating evidence supports the importance of KT around dental implants. Recent systematic reviews have demonstrated that the lack of KT is related to plaque accumulation, gingival recession, and attachment loss, which indicates that implants with insufficient KT may be prone to developing peri-implant mucositis and peri-implantitis [10, 11].
The following treatment modalities can be selected to attain a sufficient dimension of KT and vestibular depth: apically positioned flap (vestibuloplasty), free gingival graft (FGG), and use of collagen matrix (CM). Regarding the use of CM, this xenograft was developed to compensate for the disadvantages of free gingival grafts in terms of the reduction of patients’ morbidity and esthetic enhancement. However, there has been limited evidence on the stability of the reestablished tissue long-term [12–15].
10.3 Free Gingival Graft-Based Procedures
Reports on the use of palatal soft tissue graft (harvested from “the region located behind the third molar”) were originally described in 1902 at the American Dental Club of Paris meeting and published in 1904 in Dental Cosmos . Nonetheless, the use of palatal free gingival grafts (FGG) and deepening the vestibular fornix was reported in 1963 , with surgical standardization occurring some years later .
Treatment of periodontal or peri-implant sites lacking a minimum 2 mm band of attached KT
Treatment of periodontal or peri-implant sites presenting a “thin periodontal biotype” (i.e., “delicate and tiny highly scalloped gingival and osseous architecture and few or non-keratinized tissue” [8, 19–21])
Treatment of periodontal or peri-implant sites associated with toothbrushing or other environmental discomfort (i.e., pain)
Treatment of periodontal or peri-implant sites located in esthetic areas—these sites may be improved by the use of FGG-based procedure, but the final tissue color will be different from adjacent gingiva.
Treatment of sites presenting attached KT width ≥2 mm.
Treatment of sites presenting “thick and flat” (i.e., “dense, flat gingival and osseous architecture and ample width of KT tissue” [8, 19–21]) or even “thick and scalloped” (i.e., “a clear thick fibrotic gingiva and narrow zone of KT” [8, 19–21]) periodontal biotypes.
10.3.3 Principles of the Surgical Sequence
A number 15C surgical scalpel blade should be used to perform a horizontal incision in the interdental papillae at the level of the cement enamel junction (for marginal FGG), and an intrasulcular incision is made at the tooth/teeth receiving the graft (i.e., it should encompass the entire operative site). A submarginal approach may be used when the free gingiva is considered “thick” [5, 6].
Two vertical incisions made at the ends of the horizontal incision and extended to the alveolar mucosa follow, and a thin, partial-thickness flap is dissected up to the apical limits of the vertical incision and afterward completely excised.
After the recipient site/bed is completely de-epithelized, a FGG is harvested from the palate according to the size required to cover the recipient bed (Fig. 10.4c). However, the graft harvest may be influenced by the palatal vault anatomy. Reiser et al.  found that the average distance from the cementoenamel junction to the neurovascular bundle varies according to the size and shapes of hard palate, from 7 mm for shallow to 17 mm for high (U-shaped) palates. Usually, FGG can be harvested between the distal aspect of the canine and the midpalatal region of the second molar, in order to prevent potential damage and complications associated with severing the greater palatine artery and their major branches, such as hemorrhage.
The graft should be sutured to the recipient site using 5-0 or 6-0 interrupted/suspensory nylon/Teflon sutures and without leaving “dead spaces” between the lamina propria and the connective tissue side of the graft and root surface (Figs. 10.4e and 10.5b).
The sutures may be carefully removed 7–14 days after surgery to avoid injury to the graft (Fig. 10.5c). Patients should be instructed not to perform toothbrushing of the treated area during this period and directed to rinse gently with a mouthwash containing 0.12% chlorhexidine gluconate twice a day for 2–3 weeks, or until safe and comfortable, toothbrushing can be performed.
Analgesics, anti-inflammatory drugs, and/or systemic antibiotics may be prescribed if necessary.
Pain and bleeding may occur at the donor site during the early phase of healing due to exposure of the connective tissue layers of the palatal gingival tissue. On the other hand, these adverse effects will not promote alterations in the final anticipated outcomes.