Use of dental services and oral health outcomes

According to Andersen’s model of health services use, enabling resources and perceived need for care would predict use of health services [153]. As presented in Paper II, enabling resources was associated with more use of dental services, while self-reported treatment need was not. Findings from two British populations applying Andersen’s model, reported need as the main predictor of oral health behavior [156, 157]. A study of dental attendance among adult Finns also found perceived need for care to be a predictor of use of dental services in logistic regression analysis [177]. In Norway, there has been a tradition of regular dental visits, independent of oral symptoms or pain [178], which might differ from UK and Finnish populations. Also, Andersen did

hypothesize that enabling resources and need would have different abilities to predict use of health care, depending on what type of service that was examined [152]. For example, use of health services related to serious health problems and conditions would mostly be explained by need and demographic characteristics. Use of dental services can be considered more elective, thus, explained to a greater extent by social structures, health beliefs and enabling resources [153]. For the current study population, enabling resources was the main predictor of use of dental services, both as a direct effect and as a mediator for predisposing characteristics. Social structures (education, income and urbanization) were not directly associated with use of dental services, only when mediated via enabling resources. While prior research has shown that socioeconomic factors are important determinants of dental service utilization [179-181], results from Paper II indicate that higher level

of education, income and urbanization in itself does not increase people’s likelihood of regular dental visits. Use of dental services is only affected when people perceived that they have the necessary resources to attend dental services.

Paper I and II demonstrated that socioeconomic and behavioral factors are associated with periodontitis. According to results from Paper II, social structures (education, income and urbanization) and SOC were important factors in predicting both clinically measured and self-reported oral health outcomes. Higher education, income and urban residency with higher availability of dentists were related to lower levels of periodontitis in Paper I. This is consistent with previously published literature, where socioeconomic factors have been related to periodontitis [2, 32, 33, 66, 70, 182]. How socioeconomic factors influence the etiological pathway of

periodontitis is not well understood. It could be explained by differences in oral health-related behavior, access to dental health care, and norms for seeking treatment. As shown in Paper II, socioeconomic factors were related both directly and indirectly (via. e.g. enabling resources and smoking) to periodontitis. Higher education, high income and availability to dentists was also associated with less oral health impacts. This was in contrast to findings by Baker [156], where there was no direct association between socioeconomic status and self-reported oral health outcomes. Other studies of socioeconomic factors and subjective oral health support the current findings, reporting socioeconomic inequalities in oral health-related impacts [183-185].

A stronger SOC was, interestingly, related to worse periodontal status (Paper II). In previous studies of SOC and periodontitis, SOC has been related to self-perceived periodontal disease [151].

Some studies have found a weak association between SOC and extent of periodontal pockets (PD

≥4 mm) [147, 148], while other studies have not found any relationship between SOC and clinically assessed periodontitis [150, 151]. SOC is, after all, a psychological concept of how persons view their own lives, and it is plausible that it primarily affects the way individuals perceive their own health, rather than their clinically assessed health. It should also be considered that both SOC and periodontitis are positively correlated with age, which is not included in the model, and could be a potential confounder of the association between SOC and periodontitis. To further investigate this, the model could be tested in different age groups, where it could be assessed whether or not the association between SOC and periodontitis changes. Analysis in Paper II also revealed that SOC was the main predictive factor of oral health-related impacts. A stronger sense of coherence decreased the likelihood of having oral health impacts, which is in line with results from previous studies [145, 186].

Self-reported treatment need was directly and positively associated with periodontitis, although estimates were rather small. The small estimates could be explained by the fact that treatment need was not specified as periodontal treatment need, but included all needs related to oral health.

Surprisingly, treatment need was not related to oral health impacts, in contrast to previous studies of Andersen’s behavioral model and dental health [156, 157]. How participants understood the term

“treatment need” could also have had an impact on the results. Treatment need is a broad term, and can range from a need for simple tooth cleaning to more extensive dental treatment.

Smoking was identified as a factor strongly associated with periodontitis in both Paper I and II.

Regular use of dental services was related to more frequent tooth brushing, but did not affect smoking. While advice and guidelines on smoking cessation should be an important part of dental services, the current results indicate that dental services are not effective in reducing tobacco smoking.

Results presented in Paper II showed that there was a weak, and interestingly positive, association between use of dental services and periodontitis, meaning persons with frequent dental visiting habits had a slightly higher likelihood of having periodontitis. In bivariate analysis in Paper I, persons with yearly dental visits and persons only seeing dental care for acute problems did not differ in level of both non-severe and severe periodontitis. These results contradict the assumption that regular and prevention-oriented dental attendance should prevent or control periodontitis. A study of US males from 1994 found that utilization of dental services was not predictive of the extent and severity of periodontitis [187]. The same was reported for Swedish older adults, where regular dental visitors retained more teeth but had the same periodontal conditions as infrequent visitors [188]. Altogether, this calls into question the effectiveness of use of dental services in relation to periodontitis prevention and control, how it affects oral health-related behavior and raises concerns about possible under-diagnosis or failed/ineffective treatment of periodontal disease. On the other hand, it could also result from the fact that persons undergoing periodontal treatment would have more frequent dental visits. When examining regular dental attendees in more detail, periodontitis prevalence was highest among those using dental services more than once per year and lowest among those with biennial dental visits (data not shown). Moreover, successful treatment and control of periodontitis is dependent both on patient cooperation in periodontal infection control and provision of appropriate interventions and treatment by the dental care provider. Without information about what kind of dental care or treatment that was given, it is not possible to draw any conclusions about the effectiveness of dental services use related to

periodontitis prevalence.

Use of dental services had no direct effect on oral health impacts, and was only indirectly related via periodontitis. Frequent and regular dental attendance was not associated with oral health impacts in a Norwegian cohort of aging people [189]. In other studies, routine dental attendance was reported to decrease oral health impacts [125, 156].