Aim: The aim of this randomized clinical trial (RCT) is to evaluate the clinical and radiographic effectiveness of Entire papilla preservation surgical technique (EPP) to Modified minimally invasive surgical technique (M-MIST) in the treatment of periodontal intraosseous defects in stage III periodontitis patients. Methodology: A total of twenty patients (20-60) years old suffering from Stage III periodontitis were recruited, assigned and allocated randomly to one of two groups, group A (intervention group) to receive Entire Papilla Preservation technique (EPP) and group B (control group) to receive Modified Minimally Invasive Surgical technique (M-MIST). Each patient presented intra-bony defects; the selected sites were divided randomly into two treatment groups. Clinical attachment level gain (CAL gain) was recorded as primary outcome and recall appointments were carried out at 3-, 6- and 12-months post operatively. Radiographical parameters were evaluated pre-surgically and after 6 and 12 months. Patient satisfaction was evaluated at 12 months. A dropout of four patients were excluded during the study period. Results: Both groups demonstrated statistically significant improvement where group A exhibited 4.13 mm CAL gain at twelve months, while group B exhibited 3.81 mm CAL gain twelve months after treatment.