Alveolar ridge defects may limit or restrict placement of implants. The purpose of this study was to evaluate clinical and histopathologic results which occur following guided bone regeneration using platelet-rich plasma, bovine bone powder and e-PTFE membrane in the localized alveolar bone defects. Ten patients who required guided bone regeneration in implant placemnet, were slelected. Alveolar crest height and width were measured at baseline and, afer 2nd surgery 5 months later At 5 months , we obtained histopathological results as follows: 1. Alveolar crest height was an average of $8.20{pm}3.74$ mm preoperatively and decreased to an average of $7.40{pm}1.84$ mm postoperatively. There was no significant difference. 2. Alveolar crest width was an average of $4.25{pm}2.03$ mm preoperatively and significantly increased to an average of $7.20{pm}2.44$ mm postoperatively (P<0.01) 3. The change of Alveolar crest height and width were $0.80{pm}1.40$ mm, $2.95{pm}1.09$ mm 4. Histopathological evaluations revealed new bone formation with graft material and laminated bone containing the presence of osteocyte-like cell In conclusion, guided bone regeneration using platelet-rich plasma, bovine bone powder and e-PTFE membrane would provide a viable therapeutic alternative for implant placement in the localized alveolar defect or implant failure