Fig. 1

The schematic illustration of traditional and modified surgery for HGF. One of the traditional operations a1–a2 removes the overgrown tissue mainly by the external bevel incision. Another traditional operation consists with an internal bevel incision b1, crevicular incision b2 and interdental incision b3, and the flap is apically repositioned b4 Both of them have a limit on the complete removal of overgrown tissue and the preservation of gingival epithelial layer. The first incision of modified gingivectomy enters along to the sulcus c1 and down to the alveolus c2 Full thickness flap is made superior to the mucogingival junction and split thickness flap is raised inferior to the mucogingival junction c3 Dependent upon its colour and texture, the fibrotic connective tissue is removed c4 The use of handpiece and bur is for the osteoplasty c5 Flap edges are then approximated to the cemento-enamel junction (CEJ) with the flap apically repositioned c6