The need for periodontal treatment in a group of dental school patients was estimated by means of the periodontal treatment need system (PTNS). The findings were related to information about the regularity of dental visits, awareness of own disease, and periodontal treatment experience. All the patients required motivation and oral hygiene instruction (treatment need, class A). All their quadrants needed scaling or adjustment of subgingival restorations (treatment need, class B). As many as 71% of the patients and about 49% of the quadrants needed periodontal surgery (treatment need, class C). The mean periodontal treatment time per patient was 279 min (4 h 39 min). The middle age group (30-59 years) required more treatment time than the oldest group (greater than or equal to 60 years). This was probably due to more missing teeth in the oldest age group. There were no significant differences in treatment need between males and females. The regular dental visitors had a greater periodontal treatment need than the individuals visiting their dentist less frequently. This finding emphasizes the responsibility of the general practitioner in diagnosing and treating periodontal disease.