The donor tissue was harvested from tissue palatal to maxillary premolars and anterior to the mesial of the first molars. A horizontal incision corresponding to the width of the recipient bed plus 4mm was made 3 mm apical to the gingival margin. A small secondary vertical incision was tolerated on the mesial aspect of the surgical site to allow for a split thickness technique. The flap was then positioned over the graft and sutured with attempts to cover the grafted tissue to 2mm coronal to the implant/abutment interface pending flap tension. Follow up was monitored over 6 months at various time-points.

ADM graft was prepared according to the manufacturer's instructions. The preparation requires rehydration in 50ml sterile saline or Ringers Solution for five minutes and repeated twice. The graft was then transferred to the recipient bed with the basement membrane side facing up and connective tissue on the periosteum. The allograft was trimmed to cover the defect dimensions up to the implant-abutment interface. There was a 4mm margin added to the width on each side to account for lateral contraction as with the connective tissue. With sterile moist gauze, pressure was applied to the graft for proper adaptation to the wound bed. The graft was sutured with a single sling and the flap with a double sling. Simple interrupted sutures were used to close vertical releases.

All patients were treated with infiltration of local anesthetic with vasoconstrictor if noted tolerable by the medical history. Surgeons were then notified if the patient was randomized to the test or control according to a blinded treatment assignment. In both groups, anesthesia was confirmed at the implant site and the palatal donor site if indicated. The recipient bed was then prepared.

Vertical incisions were made at the defect at line angles and horizontal incisions connected the two vertical releases intrasulcularly without involving the interdental papilla. The flap was reflected as a full thickness flap maintaining the integrity of the collagen attachment with de-epithelialization of papilla to allow for coronal advancement.

Change in recession was recorded at baseline, 6 weeks, 3 months and 6 months after grafting.

At baseline, 6 weeks, 3 months, and 6 months after grafting, buccal concavities were measured.

Tissue thickness was measured with a 25 endodontic file with rubber stopper at baseline, 6 weeks, 3 months and 6 months after grafting.

Implant esthetics were rated with written survey by both the subject and clinician.