The position of internal bevel incision for gingivectomy surgeries is at

With a #15 Bard-Parker blade, the initial scalloped internal bevel incision is made at least 3 mm coronal to the mucogingival junction, including the creation of new interdental papillae. The same blade is used to thin the gingival tissues in a buccolingual direction to the mucogingival junction. At this point the blade establishes contact with the alveolar bone, and a full-thickness or a split-thickness flap is elevated.