This study examined electronic dental records of Toronto Public Health (TPH) to assess utility of the TSDDC to document morbidity, comorbidity, and changes in diagnoses. Using SPSS, the database was restructured for study purposes. Frequencies of conditions and comorbidities were obtained, numbers of patients with changed diagnoses and services they received were documented. In the study population (25860), the top three conditions were caries (78%--81%), deposits (30%--40%), and developmental disturbances (14%--23%). Smooth surface dentinal caries was most prevalent (64%--58%). The top three comorbidities with caries were deposits, developmental disturbances, and defective restorations. Between 66%--70% of all individuals had changes in subsequent diagnoses. The study validated that the TSDDC could be used to report the burden of illness and to document changes in diagnoses at all four digits. To enhance utility in program planning and evaluation the TPH database should be reinforced with software to process the coded diagnostic information.