**5. Conclusions**

The present findings sugges<sup>t</sup> that the overall oral health, barring periodontal status, of Australian adults has improved over the last 30 years. Comparisons of national data between 2004–06 and 2017–18 reveal that the periodontal health of Australian adults, in general, has deteriorated during this period. The findings also indicate that individuals from lower socioeconomic backgrounds present with poorer oral health on the whole, pointing to socioeconomic inequalities in oral health. Such findings may be useful for policy makers in planning and implementing future oral healthcare programmes at a population level.

**Author Contributions:** Conceptualization, N.A., L.L., S.C. and L.M.J.; formal analysis, S.C. and N.A.; writing—original draft preparation, N.A.; writing—review and editing, N.A., L.L., S.C. and L.M.J. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by the Australian Government Department of Health and the National Health and Medical Research Council (Partnership Grant #1115649).

**Institutional Review Board Statement:** This study was reviewed and approved by The University of Adelaide's Human Research Ethics Committee (HREC; H-2016-046).

**Informed Consent Statement:** Interviewed subjects provided verbal consent prior to answering questions. Parental/guardian consent was obtained for participants aged 15–17 years. All examined subjects provided signed, informed consent prior to the examination (parents/guardians of those aged 15–17 years provided signed, informed consent prior to the examination).

**Data Availability Statement:** The datasets used during the current study are available from the corresponding author via completion of a data request.

**Acknowledgments:** The Australian Dental Association, Colgate Oral Care and BUPA provided sponsorship. State/Territory health departments and dental services were partners in the study. The research team acknowledge the Australian Government Department of Human Services, state and territory dental health services and the participants involved in the study.

**Conflicts of Interest:** The authors declare no conflict of interest.
