Do Temporal Changes in Complete Tooth Loss Point to Cohort Effects?

ABSTRACT Objectives Complete tooth loss is more common among older adults; however, its prevalence has declined significantly over time. It is currently unknown whether age and period effects act independently or whether they interact to produce differential effects by birth cohorts. This study aimed to examine temporal changes in the prevalence of complete tooth loss in Australia, examine the effects of age, period and cohort and assess life course changes within birth cohorts. Methods The study used data from three repeated cross‐sectional waves of Australia's National Dental Telephone Interview Survey (2005, 2013 and 2021), each comprising independent samples. The prevalence of edentulism among adults aged 41 years and older was described. The independent effects of age and period and examined cohort effects were estimated using an Age‐Period‐Cohort Interaction (APC‐I) model. Results The prevalence of complete tooth loss among adults aged 41 years and older declined from 12% in 2005 to 6% in 2021. The analysis shows that while edentulism increased with age, it decreased significantly over time across most age groups. Despite the low prevalence of edentulism, younger generations showed higher‐than‐expected levels of complete tooth loss. Significant cohort effects were observed, with older cohorts showing high tooth loss and younger cohorts exhibiting concerning trends. Conclusion Despite overall progress in reducing edentulism, the increase in complete tooth loss among younger generations poses a threat to long‐term oral health outcomes in Australia. Ongoing surveillance and targeted public health interventions are critical in preventing a resurgence in tooth loss, particularly among younger populations. Comprehensive oral health programs and equitable access to care are essential to maintaining Australia's progress in oral health and in addressing emerging challenges.