## 1 Introduction  
Gingival recession (GR) is defined as the apical displacement of the gingival margin in relation to the cementoenamel junction (CEJ), which exposes the root surfaces to the oral environment and is associated with attachment loss [1]. It occurs frequently in adults and increases with age [2], regardless of the level of oral hygiene [3]. It is a common clinical problem and can affect the root surface of one or several teeth, being more frequent on the vestibular surface of single-rooted teeth [1]. While in most cases gingival recessions are symptomless, the patient may see them as an esthetic problem [4] that sometimes hinders or prevents good oral hygiene and may increase the risk of root hypersensitivity [5], caries, and non-caroious cervical lesions [6]. In recent decades, it has been shown that complete root coverage in single and multiple recessions can be predictably achieved with different techniques [7, 8]. Of these procedures,the coronally advanced flap with connective tissue graft (CTG) is the most effective treatment of recession with or without clinical interproximal attachment loss [9; 10; 11]. Most clinical trials tend to focus on maxillary gingival recessions (esthetic zone), while little information is available on treatment of mandibular defects [12]. There are various anatomical and mucogingival conditions in the mandibular anterior region, especially sextant V, that make treatment of an isolated or multiple GR in that region different to that performed in other sextants. Consequently, clinicians may encounter aberrant frenums with a very coronal insertion, high muscle attachment, a larger avascular surface area, malpositioned teeth that impede effective decision-making and surgical outcomes [1], shallow vestibules, and/or the presence of a thin phenotype [13]. The onset or progression of GR during or after orthodontic treatment is also more common in this region [14]. It is also important to remember that orthodontics has a vital role in managing and resolving periodontal problems [15]. In these situations, the choice of technique will depend on the characteristics of the recession and whether it is single or multiple. Several surgical techniques have been described for treating single and multiple gingival recessions in the anterior mandibular zone, including the free gingival graft technique [16], subepithelial connective tissue graft, as well as several flap designs: the envelope flap [17], coronally advanced flap [18], lateral sliding flap [19], double pedicle flap [20] and laterally closed tunnel flap [21]. For multiple gingival recessions in sextant V, the most well-tested and predictable techniques are the bilaminar approaches such as the tunnel technique [22] and the coronally advanced flap technique [23]. However, most of these surgical techniques lead to further collapse of the vestibule, compromise the vascular supply and fail to produce predictable results in terms of complete root coverage while, in the case of the free gingival graft technique, the outcome is rather unesthetic (dissatisfaction with color matching and soft tissue texture, as well as misalignment of the mucogingival junction) [24; 25]. An esthetic gingival recession scoring system (RES) has been developed to evaluate the esthetic outcome of root coverage (RC) procedures [26]. This score is based on the evaluation of five variables: the gingival margin level, gingival contour, soft tissue texture, mucogingival junction alignment, and gingival color. Sixty percent of the RES value is attributed to the level of the gingival margin, since one of the main goals of the treatment is complete root coverage (CRC), and 40% is attributed to the other four variables. The sum of the five variables produces an RES score, ranging from 0 (final recession equal or apical to the initial recession) to 10 (the best esthetic result).