Lee YM， Kim DY， Kim JY， Kim SH， Koo KT， Kim TI， Seol YJ. Peri-implant soft tissue level secondary to connective tissue graft in conjunction with immediate implant placement: A 2-year follow-up report of 11 consecutive cases. Int J Periodontics Restorative Dent 2012;32:213-222. Koo KT， Wikesjo UME， Park JY， Kim TI， Seol YJ， Ku Y， Rhyu IC， Chung CP， Lee YM. Evaluation of single-tooth implants in second molar region: A 5-year life-table analysis of a retrospective study. J Periodontol 2010;81:1242-1249. Shin JH， Kim KH， Kim SH， Koo KT， Kim TI， Seol YJ， Ku Y， Rhyu IC， Chung CP， Lee YM. Ex vivo bone morphogenetic protein-2 gene delivery using gingival fibroblasts promotes bone regeneration in rats. J Clin Periodontol 2010;37:305-311. Kim SH， Kim KH， Seo BM， Koo KT， Kim TI， Seol YJ， Ku Y， Rhyu IC， Chung CP， Lee YM. Alveolar bone regeneration by transplantation of periodontal ligament stem cells and bone marrow stem cells in canine peri-implant defects model: A pilot study. J Periodontol 2009;80:1815-1823. Kim SH， Kim DY， Kim KH， Ku Y， Rhyu IC， Lee YM. The efficacy of a double-layer collagen membrane technique for overlaying block graft in a rabbit calvarium model. Clin Oral Implants Res 2009;20:1124-1132. Lee YM， Shin SY， Kim JY， Kye SB， Ku Y， Rhyu IC. Bone reaction to bovine hydroxyapatite for maxillary sinus floor augmentation: Histologic results in human. Int J Periodontics Restorative Dent 2006;26:471-481.