Free gingival technique will be done

A horizontal partial thickness incision will be trace at the MGJ to dissect the alveolar mucosa from the keratinized tissue. The alveolar mucosa will be dissected from the underlying periosteum to create an envelope of 4-5 mm apical to the bone dehiscence associated with the gingival recessions. The keratinized tissue coronal to the first incision and neighboring the recession will be de-epithelialized to expose the connective tissue and create a trapezoidal recipient bed having a large apical base at the MGJ and a narrower coronal base just coronal to the CEJ of the experimental units. The grafts will be taken from the palate.The grafts will be positionned with the coronal edge of the CEJ.

Interrupted sutures (6-0 polypropylene, prolene) will be positionned to stabilize the graft. Sling crossed sutures anchored to the periosteum apical to the graft and placed to ensure a tight adaptation of the graft to the root surface

A digital scan of the arch will be performed with an optical 3D measurement system (3Shape Trios) creating STL files. The corresponding reference and follow-up examinations of each clinical case will be virtually overlaid and combined into a common coordinate system (Geomagic, 3D Systems) using the Control X tool. By using of the buccal surfaces of the affected teeth as reference points for the superposition of the different time points

A spectrophotometer (Easy Shade, VITA) will be used for the evaluation of the gingiva color. Before each measurement, the camera will be calibrated. To objectively measure gingiva discoloration, spectrophotometric measurements of the buccal gingiva will be performed on the study and on the adjacent untreated control tooth. The spectrophotometer camera will be positioned perpendicular to the mid-buccal gum and two images will be captured at each site.The center of the area of interest will be located 1.5 mm apical to the mid-buccal gingival margin and 3 mm.

The spectral analysis will generate the CIE-Lab (Commission Internationale d'Eclairage) color coordinates L: luminosity, a: chroma along the red-green axis and b: chroma along the yellow-blue axis. The total color difference DE between the gingiva will be calculated according to the formula DE = [(Limpl Lcontr) 2 + (aimpl acontr) 2 + (bimpl bcontr) 2] 1/2 (CIE 2004)

A spectrophotometer (Easy Shade, VITA) will be used for the evaluation of the gingiva color. Before each measurement, the camera will be calibrated. To objectively measure gingiva discoloration, spectrophotometric measurements of the buccal gingiva will be performed on the study and on the adjacent untreated control tooth. The spectrophotometer camera will be positioned perpendicular to the mid-buccal gum and two images will be captured at each site.The center of the area of interest will be located 1.5 mm apical to the mid-buccal gingival margin and 3 mm.

The spectral analysis will generate the CIE-Lab (Commission Internationale d'Eclairage) color coordinates L: luminosity, a: chroma along the red-green axis and b: chroma along the yellow-blue axis. The total color difference DE between the gingiva will be calculated according to the formula DE = [(Limpl Lcontr) 2 + (aimpl acontr) 2 + (bimpl bcontr) 2] 1/2 (CIE 2004)