To access the defect, a single horizontal or oblique apical incision will be made in the mucosa located on the bony cortex, far from the marginal tissues and apically to the edge of the bony crest delimiting the defect. The incision will be extended mesiodistally as necessary to allow access to the defect and correct debridement of the granulation tissue. The tissue coronal to the incision will be raised full thickness, trying to maintain the preoperative papillae architecture intact. The granulation tissue and epithelium of the pocket will be eliminated. The affected root will be scaled and planed, and calculus eliminated. Once the defect will be debrided, the enamel matrix derivates will be applied. Then the incision line will be sutured by a double suture line to facilitate closing without tension: The first with internal horizontal mattress sutures to approximate the connective tissue of both edges of the mucosal incision, and the second with single interrupted sutures.

A small incision in the palatal aspect and a limited papila elevation to the buccal aspect will be made for treating isolated periodontal defect. Enamel matrix derivates will be applied on the debrided root surfaces.

The incision of the defect-associated papilla will be performed according to the principles of the papilla preservation techniques. Enamel matrix derivates will be applied on the debrided root surfaces. Stable primary closure of the flaps will be obtained with internal modified mattress sutures.

Periodontal reconstructive surgery

Probing pocket depth will be assessed with a periodontal probe, measured in mm from the gingival margin to the bottom of the pocket

Clinical attachment level will be assessed with a periodontal probe, measured in mm from the cementoenamel junction (CEJ) to the bottom of the pocket.

Recession, will be assessed with a periodontal probe, measured in mmm on the buccal aspect, from the CEJ to the gingival margin zenith.

Location of the tip of the papillae. Taking as reference the level of the mid-axis of the tooth, will be measured the distance from the CEJ at the zenith of the tooth to the tip of the papilla. A positive value will be recorded when the tip of the papillae is located coronally to the CEJ and a negative value otherwise.

This outcome will be assessed with a periodontal probe and measured in mmm.

Keratinized tissue width will be assessed with a periodontal probe, measured in mm on the buccal aspect, from the gingival margin to the mucogingival line.

Bleeding on probing could be positive or negative.