Dental caries is the most common oral condition and remains a major problem in the adult population of both developing and industrialized countries 1. More than 90% of dental caries remains untreated in third world countries 2. A Cross-sectional study in 2000 which examined dental caries and nutritional status showed a predominantly downward trend in the prevalence of caries in South Africa, particularly in the 5–6 year and 35–44 age groups, despite this there is also evidence of increased sugar consumption3. Findings from the 2001 South African Oral Health Survey showed that almost 60% of 6-year-old children had dental caries which was above the 50% target set by the Department of Health (DOH) 4. Furthermore, 80% of all dental caries in children in South Africa went untreated 5. Our unpublished study, which was carried out in two districts in KwaZulu-Natal (KZN), South Africa, reported an overall prevalence of dental caries among the population of health seekers visiting public dental facilities of 63% 6.
Various demographic and behavioral risk factors such as diet, alcohol, smoking, socioeconomic status, water source, gender and education level that are associated with dental caries among adults have been evaluated by different investigators in different parts of the world. It is well established that demographic variables, diet, use of fluorides, oral hygiene and access to health service are some of the predictors of dental caries 7,8.
It is evident from the literature that age is associated with the type of dental caries. For example, a survey in the United States of America (US) found that 94% of adults showed evidence of past or present coronal caries whereas children tend to have more occlusal caries 9.
There seem to be mixed findings on the association between sex and dental caries. An oral health survey done in 2001 in Germany showed that women had more dental caries than men 10. An oral health survey amongst the adults and the elderly in Hungary, in 2004, did not show any significant differences between men and women 11. These findings are consistent in literature.
A cross-sectional study which explored the association between parents’ education status and tooth loss among Korean Elders found that a strong relationship between socioeconomic status (SES) and oral health 12. Other authors have found that as SES increases, disease, illness, and their impacts decrease 13. In a large-scale epidemiological survey among the Southern Chinese, socio-economic factors had a considerable effect on dental caries status. Individuals who were unemployed, or had no income, had higher dental caries scores compared to the those employed and with a higher income 14.
In another cross-sectional study in 2017 which sought to determine the association between SES and dental caries in elderly people in Sichuan Province, China, the burden associated with dental caries remained high in disadvantaged, poor and older populations 15. In addition, a systematic review and meta-analysis study in 2015 which explored socioeconomic inequality and dental caries found that those with lower educational level or lower income, were most likely to have a higher risk of caries lesions 16.
A 2019 systematic review and meta-analysis study reported a positive association between tobacco smoking and dental caries17. This finding was further reinforced in a Swedish prospective study which explored tobacco use and caries increment in young adults which reported that smoking had a relative risk of 1.5 of increasing dental caries over 3 years. This study further concluded that habitual smoking is a risk factor for caries in young adults 18.
There seems to be mixed evidence regarding the association between alcohol use and dental caries. A cross sectional study conducted in India on alcohol dependency and oral health, reported that alcohol-dependent subjects had slightly lower mean plaque and salivary pH, and a higher prevalence of dental caries, periodontitis and mucosal lesions, compared with nonalcoholic subjects 19. Another study on the prevalence of dental caries in chronic alcoholics conducted in Eastern Europe reported no major differences in the prevalence of caries in alcoholics compared to the non-alcoholics group 20. A 2015 study which explored smoking, alcohol use, socioeconomic background and oral health among young Finnish adults found that the consumption of alcohol was not associated with dental caries and periodontal disease 21.
There is a plethora of evidence in the literature that points to an association between dental caries and type of diet. A cross-sectional study among young adults in 2004 in Turkey, found a strong association of dental caries with sugar consumption 22. The 2014, National Health and Nutrition Examination Survey in the US reported a lower prevalence of dental caries among individuals following a Healthy Eating Index. This finding supports the notion of a heathy diet contributing to lower dental caries 23. This is supported by another study in the US which reported that dietary patterns were associated with the prevalence of dental caries. It further concluded that while food groups high in sugar were associated with the prevalence and severity of caries, associations were more apparent in the context of overall diet 24.
Oral health services and public health facilities in KZN constantly experience huge challenges such as poor prioritization, under-funding, limited resource allocation, overcrowding and often patients presenting late to seek help with advanced disease. On the other hand, there are various patient factors known in public health literature such as genetic, environmental exposure and social that will impact irrespective of the patients acquiring a particular disease. It is thought that an understanding of some of the risk facts that patients are exposed to even before they seek help from public health facilities may assist in educating and mitigating these factors and improve patient’s oral health condition.
In addition, the association of dental caries and risk factors has been widely reported in the literature, however, there is a paucity of data in KZN and South Africa. It is therefore imperative to identify the risk factors associated with dental caries among adults attending public oral health facilities in KZN, South Africa in order to contribute to knowledge about these risk factors and educate the public.
The present study aimed to determine the risk factors/predictors associated with dental caries among adults attending dental clinics at public health facilities in eThekwini and uMgungundlovu districts in KZN province over a 5-month period. The adults were chosen as the results of our previous study on the prevalence of common oral conditions demonstrated that the adults had a higher prevalence of dental caries compared to the other groups.