Coronally advanced flap in combination with a connective tissue graft.

According to the technique(Zucchelli & De Sanctis 2000), this procedure consists of a rotated papilla, envelope flap. Intrasulcular incisions will be performed involving all the experimental units and at least one tooth mesial and distal to the experimental teeth. From the centre of rotation the incisions will be traced in a corono-apical direction toward the mesial and toward the distal extension of the flap.

After the accurate initial incisions, the flap will be raised full thickness apical to the mucogingival junction (MGJ), exposing 1 to 2 mm of bone at the base of the recession/dehiscence defects.

A linear mesio-distal incision will then be performed to cut the periosteum, releasing any muscular tension and allow a passive coronal positioning of the flap to cover the CEJ.

Tunnel technique in combination with a connective tissue graft.

When tunnelling procedures are applied, this technique consists of a supra-periosteal bed under a pedicle flap without any external incisions (Zabalegui et al. 1999). Afterwards, a connective tissue graft is placed and secured through the tunnel, covering the adjacent exposed roots.

To create a tunnel at the buccal aspect of the gingiva, sulcular partial-thickness incisions are made by means of a micro-blade through each recession area, extending the split-thickness beyond the mucogingival junction (MGJ). The partial dissection plane is then extended laterally through the papillae between the treated teeth without separating them. This incision must also be extended 3 to 5 mm mesial and distal from the lateral teeth to allow space for the connective tissue graft.

A connective tissue graft will be harvested from the palate as a free gingival graft, which will be de-epithelialized with a 15-c blade(Zucchelli et al. 2010) before opening of the opaque envelopes, which contains the allocation concealment. The dimensions of the graft achieve 3 to 5 mm mesial and distal from the lateral teeth with an ideal thickness about 1 to 1.5 mm. Donor tissue will be taken at premolar and molar level. In control sites, the graft will be adapted to cover each exposed root to the CEJ, and stabilized with either 6-0 resorbable sutures (with the knot placed under the papillary area) or a non-resorbable suture with the knot on the palatal side. For suturing of the graft, interrupted sutures or sling sutures (anchored to periosteum apical to the graft and hanging around the neck of the experimental teeth) may be used.

The complete root coverage is defined as the percentage of cases that 100% of the recessions will be covered in their whole extension.

The mean root coverage is the percentage of recession extension, which will be covered at 6 months after surgery.

It is described as the changes in recession measurements between baseline and 6 months post-operative. Recession is defined as position of the gingival margin. All included recessions will be measured with two methods:

1. from the CEJ to the gingival margin
2. from the incisal edge to the gingival margin All measures will be taken using as reference the most apical position of the gingival margin on the facial aspect of the tooth.

This assessment is aimed at understanding the concerns that a patient has with recession of the gingival margin. The level of concern will be examined with a patient questionnaire on a 5-point Likert scale in terms of aesthetics, sensitivity to cold, sensitivity to brushing, root/tooth wear, fear to lose the involved teeth. The instrument will be used at baseline and at the 6-month follow-up appointment. The patient's response will be categorised based on their concern: 1)no concerned 2)a bit concerned 3)some concerned, 4)concerned 5)quite concerned