'Practice activity patterns of dentists in Australia: trends over time by age of patients' presents findings on the activity of dentists in private general practice from The Longitudinal Study of Dentists' Practice Activity. Data for this study, based on a random sample of dentists, have been collected at five-year intervals since 1983-84. Trends over time in the characteristics of patients and visits, and services provided are presented by age of patients for the period 1993-94 to 2003-04. With increasing numbers of older patients who are retaining their teeth, these patients may have complex treatment needs that require more services and take longer to complete. These changes in oral health have resulted in decreased visits for dental problems and increased visits for recall/maintenance care among patients aged 45-64 years and 65 years or more. Such changes in oral health, demographics and use of services are expected to impact on the practice activity of dentists.