What explains socioeconomic inequalities in dental flossing? Cross-sectional results from the RaNCD cohort study


Dental flossing
Health inequalities
Concentration index
Decomposition analysis


Introduction: The magnitude of or determinants underlying socioeconomic inequalities in the use of dental floss is poorly understood in Iran. This study aimed to measure and decompose socioeconomic inequalities in dental flossing in Ravansar, Iran.

Methods: This cross-sectional study used data of 10002 individuals aged 35-65 years obtained from the Ravansar Non-communicable Disease (RaNCD) cohort study located in Kermanshah province, west of Iran.  Socioeconomic status was measured through an asset-based method and principal component analysis was carried out to determine the socioeconomic status (SES). The concentration index and curve were used to measure socioeconomic inequality in dental flossing. Decomposition analysis was also used to determine the main determinants that contribute to inequalities in dental flossing.

Findings: Of 10,002 participants, 11.74% were found to use dental floss. The normalized CI for use of dental floss was 0.327 in the entire population, 0.323 in females and 0.329 in males, indicating that the use of dental floss is more concentrated among high-SES individuals. The decomposition analysis indicated that SES (50.58%) and level of education (44.90%) respectively contributed the most to this inequality. Place of residence (10.55%) and age group (2.7%) were the next main contributors, respectively.

Conclusion: There are a low prevalence and a relatively high degree of pro-rich socioeconomic-related inequality in dental flossing among Iranian adults. Socioeconomic status, level of education and place of residence contributed the most to the observed inequalities in dental flossing. Policy interventions should consider these factors to reduce inequality in the use of dental floss and increase the prevalence of dental flossing.




1. Jin, L., et al., Global burden of oral diseases: emerging concepts, management and interplay with systemic health. Oral diseases, 2016. 22(7): p. 609-619.
2. Cohen-Carneiro, F., R. Souza-Santos, and M.A.B. Rebelo, Quality of life related to oral health: contribution from social factors. Ciência & Saúde Coletiva, 2011. 16: p. 1007-1015.
3. Asgari, F., et al., Oral hygiene status in a general population of Iran, 2011: a key lifestyle marker in relation to common risk factors of non-communicable diseases. International journal of health policy and management, 2015. 4(6): p. 343.
4. Hyde, S., et al., Prevention of tooth loss and dental pain for reducing the global burden of oral diseases. International dental journal, 2017. 67(S2): p. 19-25.
5. Marcenes, W., et al., Global burden of oral conditions in 1990-2010: a systematic analysis. Journal of dental research, 2013. 92(7): p. 592-597.
6. Araujo, M.W., et al., Meta-analysis of the effect of an essential oil–containing mouthrinse on gingivitis and plaque. The journal of the American dental association, 2015. 146(8): p. 610-622.
7. Fleming, E.B., et al., Prevalence of daily flossing among adults by selected risk factors for periodontal disease—United States, 2011–2014. Journal of periodontology, 2018.
8. Hamilton, K., et al., Translating dental flossing intentions into behavior: A longitudinal investigation of the mediating effect of planning and self-efficacy on young adults. International journal of behavioral medicine, 2017. 24(3): p. 420-427.
9. Worthington, H.V., et al., Home use of interdental cleaning devices, in addition to toothbrushing, for preventing and controlling periodontal diseases and dental caries. Cochrane Database of Systematic Reviews, 2019(4).
10. American Dental Association (ADA). Statement on Regular Brushing and Flossing to Help Prevent Oral Infections. American Dental Association; 2013. 2019-05-03]; Available from: https://www.ada.org/en/press-room/news-releases/2013-archive/august/american-dental-association-statement-on-regular-brushing-and-flossing-to-help-prevent-oral. 2019-05-03]; Available from: https://www.ada.org/en/press-room/news-releases/2013-archive/august/american-dental-association-statement-on-regular-brushing-and-flossing-to-help-prevent-oral.
11. Gholami, M., N. Knoll, and R. Schwarzer, A brief self-regulatory intervention increases dental flossing in adolescent girls. International journal of behavioral medicine, 2015. 22(5): p. 645-651.
12. Kauer, B., et al., Self-reported Use of Dental Floss over 13 Years: Relationship with Family Income, Mother's Age and Educational Level. Oral health & preventive dentistry, 2016. 14(1).
13. Capurro, D.A. and M. Davidsen, Socioeconomic inequalities in dental health among middle-aged adults and the role of behavioral and psychosocial factors: evidence from the Spanish National Health Survey. International journal for equity in health, 2017. 16(1): p. 34.
14. Guarnizo-Herreño, C.C., et al., Socioeconomic position and subjective oral health: findings for the adult population in England, Wales and Northern Ireland. BMC Public Health, 2014. 14(1): p. 827.
15. Tsakos, G., et al., Social gradients in oral health in older adults: findings from the English longitudinal survey of aging. American journal of public health, 2011. 101(10): p. 1892-1899.
16. Bof de Andrade, F., F.C. Drumond Andrade, and K. Noronha, Measuring socioeconomic inequalities in the use of dental care services among older adults in Brazil. Community dentistry and oral epidemiology, 2017. 45(6): p. 559-566.
17. Safiri, S., et al., Socioeconomic inequality in oral health behavior in Iranian children and adolescents by the Oaxaca-Blinder decomposition method: the CASPIAN-IV study. International journal for equity in health, 2016. 15(1): p. 143.
18. Lindmark, U., M. Hakeberg, and A. Hugoson, Sense of coherence and its relationship with oral health–related behaviour and knowledge of and attitudes towards oral health. Community dentistry and oral epidemiology, 2011. 39(6): p. 542-553.
19. Sahn, D.E. and D. Stifel, Exploring alternative measures of welfare in the absence of expenditure data. Review of income and wealth, 2003. 49(4): p. 463-489.
20. Vyas, S. and L. Kumaranayake, Constructing socio-economic status indices: how to use principal components analysis. Health policy and planning, 2006. 21(6): p. 459-468.
21. Howe, L.D., J.R. Hargreaves, and S.R. Huttly, Issues in the construction of wealth indices for the measurement of socio-economic position in low-income countries. Emerging themes in epidemiology, 2008. 5(1): p. 3.
22. McKenzie, D.J., Measuring inequality with asset indicators. Journal of Population Economics, 2005. 18(2): p. 229-260.
23. O’Donnell, O., et al., Analyzing health equity using household survey data. . World Bank Publications. Retrieved from.
1195594469249/HealthEquityFINAL.pdf., 2008.
24. Wagstaff, A., The bounds of the concentration index when the variable of interest is binary, with an application to immunization inequality. Health economics, 2005. 14(4): p. 429-432.
25. Wagstaff, A., E. Van Doorslaer, and N. Watanabe, On decomposing the causes of health sector inequalities with an application to malnutrition inequalities in Vietnam. Journal of econometrics, 2003. 112(1): p. 207-223.
26. Kasmaei, P., et al., Brushing behavior among young adolescents: does perceived severity matter. BMC Public Health, 2014. 14(1): p. 8.
27. Levin, K. and C. Currie, Inequalities in toothbrushing among adolescents in Scotland 1998–2006. Health education research, 2008. 24(1): p. 87-97.
28. Perera, I. and L. Ekanayake, Influence of oral health‐related behaviours on income inequalities in oral health among adolescents. Community dentistry and oral epidemiology, 2011. 39(4): p. 345-351.
29. Polk, D.E., R.J. Weyant, and M.C. Manz, Socioeconomic factors in adolescents’ oral health: are they mediated by oral hygiene behaviors or preventive interventions? Community dentistry and oral epidemiology, 2010. 38(1): p. 1-9.
30. Shen, J., J. Wildman, and J. Steele, Measuring and decomposing oral health inequalities in an UK population. Community dentistry and oral epidemiology, 2013. 41(6): p. 481-489.
31. Allin, S., Does equity in healthcare use vary across Canadian provinces? Healthcare Policy, 2008. 3(4): p. 83.
32. Wamala, S., J. Merlo, and G. Boström, Inequity in access to dental care services explains current socioeconomic disparities in oral health: the Swedish National Surveys of Public Health 2004–2005. Journal of Epidemiology & Community Health, 2006. 60(12): p. 1027-1033.
33. Asgari, I. and A.E. Ahmady, Social Factors and Dental Health in the Urban Adolescents of Isfahan, Iran. Oral health and dental management, 2014. 13(3): p. 798-804.
34. Ha, D.H., et al., Changes in area-level socioeconomic status and oral health of indigenous Australian children. Journal of health care for the poor and underserved, 2016. 27(1): p. 110-124.
35. Jamieson, L.M. and W.M. Thomson, Adult Oral Health Inequalities Described Using Area‐based and Household‐based Socioeconomic Status Measures. Journal of Public Health Dentistry, 2006. 66(2): p. 104-109.
36. Hakeem, F.F. and W. Sabbah, Is there socioeconomic inequality in periodontal disease among adults with optimal behaviours. Acta Odontologica Scandinavica, 2019. 77(5): p. 400-407.
37. Sabbah, W. and A. Sheiham, The relationships between cognitive ability and dental status in a national sample of USA adults. Intelligence, 2010. 38(6): p. 605-610.