To determine the prognosis of the overall dentition and of individual teeth will help the clinician in making a proper treatment plan for the patient. However, few studies really evaluate the effectiveness of those current clinical factors for assigning accurate prognosis. There is also no effective method which can assign the prognosis based on a clear, objective, clinical criteria. This article is a review of the current factors which can be considered in determining the periodontal prognosis. Based on the diagnosis, etiology, disease severity and the prognosis, a well planned periodontal treatment can then be established. The treatment plan will encompass different therapeutic objectives for each patient according to his or her needs in order to create a well-functioning healthy dentition.