Aim: The aim of our study was to assess and compare true as well as surrogate end points for the most commonly performed procedure - the periodontal flap surgery using Dental Impact on Daily Living (DIDL) questionnaire. Methods and Material: Forty subjects who underwent periodontal flap surgery for generalized chronic and aggressive periodontitis in the Department of Periodontology, Indira Gandhi Institute of Dental Sciences were enrolled in this study. Clinical parameters (surrogate end points) such as gingival index (GI), probing pocket depth (PPD) and clinical attachment level (CAL) were recorded and DIDL questionnaire was administered pre surgery and after six months to assess true end points. Results: Patient based outcome parameters such as bad breath, bleeding gums, food being trapped between teeth had significant improvement after flap surgery whereas sense of loose teeth in the mouth, appearance, sensitivity and sense of confidence while interacting with others did not show improvement post operatively. Conclusion: Significant improvements in surrogate end points do not always translate to achievement of true end points. Most of the time periodontal therapy alone contributes only to elimination of etiology. True end points in terms of comfort, functionality, esthetics and social interaction can be achieved only through interdisciplinary practice.