The purpose of this study was to investigate the degree of compliance with supportive periodontal therapy(SPT), to determine if any significant differences existed in the characteristics of compliant, erratically compliant and non-compliant patients and to identify reasons for poor compliance.

Four hundred five patients who initially visited between July 2003 and December 2004 and were treated until June 2005 were retrospectively evaluated for their compliance with SPT in terms of attendance for a recommended schedule of visits. Patients' compliance was classified as complete compliance(attended more than 80% of the recommended appointments), erratic compliance(attended less than 80% of the recommended appointments or discontinued) and non-compliance(did not return for SPT). Analysis was made for each group to correlate the degree of compliance with gender, age, smoking, distance between their houses and the hospital, disease severity, type of therapy, implant, plaque control instruction and systemic diseases. Tele research of erratically compliant and non-compliant patients was carried out to identify reasons for their poor compliance.

Only 24.7% of the patients were in complete compliance. The highest drop-out rate(32.4%) occurred in the first year. A significantly greater percentage of non-smokers and patients who finished plaque control instruction were in complete compliance. A significantly greater percentage of patients without implant and patients who had been treated by only scaling and root planing were in non-compliance. More males were found to be compliant with SPT, although this was marginally significant. There were no significant differences between compliant, erratically compliant and non-compliant patients with regard to age, distance, disease severity and systemic disease. The survey revealed that the main reasons for poor compliance with SPT were inconvenient location and insufficient time.

Patients' compliance with SPT was poor and the highest drop-out rate(32.4%) occurred in the first year. Significant relationships were found between the degree of compliance and smoking, type of therapy, implant, plaque control instruction and gender.