the infectious nature of dental caries , its early onset and its early treatment potential requires emphasis on early preventive dental care in children ( 1 ) . direct relationship between parents oral hygiene behavior and their children s oral health - related habits , emphasize the key role of parents ( 2 ) . children from low - income families and ethnic minorities have been shown to have poor oral hygiene , infrequent dental visits , less use of preventive dental services and higher untreated carious lesions ( 1 , 3 ) . similarly , saied moallemi et al . ( 4 ) found direct relationship between the parents high educational level and the presence of restoration in their children s deciduous teeth . in addition to socio - economic determinants of health , special attention arose toward the role of health literacy on public health ( 5 ) . adapted from health literacy background , oral health literacy is  the degree to which individuals have the capacity to obtain , process , and understand basic health information and services , needed to make appropriate health decisions  ( 6 ) . it has recently been considered as an important determinant of oral health ( 7 ) . respectively , lower caregivers oral health literacy was associated with a child s high caries risk related behavior such as use of night time bottle and absence of daily teeth or gums brushing ( 8) . high caregiver oral health literacy was also negatively correlated with their children s dmft index and visible plaque index ( 9 ) . while , studies on oral health literacy are gradually becoming worldwide , data on this topic is rare in iran . study of health literacy in five provinces in iran revealed that two - thirds of adults had inadequate levels of health literacy ( 10 ) . ( 11 ) also found a low average of oral health literacy levels among iranian adults , specifically men , the less educated and those receiving oral health information from few sources . however , no studies have been conducted about the effect of parents oral health literacy on children s oral health in iran . therefore , the aim of this study was to evaluate the effect of parents oral health literacy on children s dental health . a total of 384 children aged 21 months to 84 months who attended the dental clinic of babol university of medical sciences , babol , iran , between september 2015 and february 2016 were examined . the examiner was a final year undergraduate dental student who , before initiating the project , participated in some training sessions such as dmft index workshop , and the questionnaire protocols which had all been explained by the main researcher at the dental faculty . patients who attended the pediatric clinic faculty of dentistry were selected , using non randomized simple method . because preschool children s oral health is mostly controlled by parents ( 12 ) , we selected this age group in order to show parents long - term supervision of children s oral health . clinical data measured only for primary dentition as d ( dental caries of deciduous teeth ) , m ( missing deciduous teeth due to dental caries ) , and f ( filling of deciduous teeth due to dental caries ) , using standard probe of  who  at the dental clinic . during examination children s parents completed the  oral health literacy - adults questionnaire ( ohl - aq ) , which showed to be valid and reliable to measure oral health literacy skill of adults ( 13 ) . it contains 17 items in four sections : reading comprehension to assess reading literacy and oral health knowledge ; numeracy to assess calculating literacy in a dental prescription , and a mouth - rinse instruction ; listening to evaluate effectiveness of communication skills ; and decision - making which shows applied literacy skills related to common oral health problems and items extracted from medical history form . the total score for the questionnaire ranged from 0 to 17 . for analysis , we reclassified the ohl - aq scores into two levels : inadequate , 011 ( combining the categories of  inadequate  and  marginal  ) ; and adequate , 1217 ( 13 ) . socio - demographic data was acquired comprising children s age and gender , parents educational level , parents  job , and family residential region . parents educational level was measured by linking both parents years of education and classified as : low ( both parents under 12 years of education ) , medium ( one parent under 12 years of education ) , or high ( both parents 12 or more years of education ) . parents job was categorized as : both parents employed , one parent employed , and both parents unemployed . while both rural and urban residents attended the dental faculty clinic , family residential region in addition to descriptive statistics , the statistical significance of children s dental caries , missing , and dental fillings mean differences between subgroups was compared by one - way analysis of variance ( anova ) , and an independent - samples t - test . two multiple linear regression model served to test which variables associated with children s dental caries and dental fillings , controlling for background characteristics and oral health literacy level . , armonk , ny , usa ) . the ethics committee of the babol university of medical sciences approved the study . before being invited to take part , participants were informed of the scientific goal of this research , participation being voluntary and their right to withdraw at any time . in all , 384 children ( 47% girls ) aged 2184 months participated , while 85% were 3784months old . the mean age was 55.1 ( sd : 13.7 ) . of the examined children , mean dental caries was 6.5 , mean missing was 0.4 , mean filling was 1.2 , and mean dmft index was 8.2 , respectively . unemployed parents ( p<0.001 ) , parents with low level of education ( p=0.001 ) , and those who were living in rural regions ( p=0.001 ) , had children with higher dental caries ( table 1 ) . girls ( p=0.02 ) and younger ones ( p<0.001 ) showed less dental caries , while children who were living in urban regions had more dental fillings ( p=0.002 ) ( table 1 ) . parents with inadequate ohl had children with more dental caries ( p=0.005 ) , while parents with adequate ohl had children with more dental fillings ( p=0.001 ) ( table 1 ) . with regards to the multiple linear regression results , unemployment of both parents was significantly associated with increased children s dental caries ( p<0.001 , 95% ci : 5.64 to 13.45 ) ( table 2 ) , living in urban regions ( p=0.01 , 95% ci : 0.11 to 1.12 ) , and parents with adequate ohl ( p=0.02 , 95% ci : 0.08 to 1.05 ) were significantly associated with more children s dental fillings ( table 3 ) . the present study results revealed that inadequate parents ohl was associated with high children s dental caries and less dental fillings . the regression model , however , confirmed significant relation of lower parents ohl and less children s dental fillings controlling for family s socio - economic determinants . previous studies also linked inadequate caregiver s ohl to high children s dental treatment needs ( 3 ) , high children s dmft index ( 9 ) , and adverse early childhood oral health outcome ( 8) . in addition , we found that , parents low educational level , parents unemployment , and living in rural regions was associated with higher children s dental caries status . in regression model however , parents unemployment remained as a significant related factor to higher children s dental caries , indicating a notable role of economic status in children s oral health compared to other socio - demographic determinants . ( 9 ) found that low parents educational attainment and low family income were associated with high children s dental caries status . considering our study , children s oral health from their living areas revealed high dental caries and low dental fillings of rural children compared to those living in urban areas . availability of unhealthy and sugary foods and beverages in villages similar to major cities , limited dental health services in rural regions ( 14 ) , and lack of oral health prevention knowledge may contribute to poor children s oral health in rural communities . while reducing dental health services disparities in rural areas faces a multitude of challenges , regarding the present study results , improving ohl of deprived individuals seems to carry a lot of potential to promote children s oral health , specifically in countries with a developing oral health care system , such as iran . providing interventions in settings such as health care centers where pregnant women and children under six years referred regularly , would be beneficial for improving caregivers , specifically mothers ohl skills . adequate mothers skills in relation to their child s oral health , leads to improved health practices in mother - child pairs ( 2 ) . ( 8) also concluded that interventions to enhance caregivers oral health literacy would be a successful strategy to improve young children s oral health . the results of the present study showed an increase in the rate of dental caries with children s aging , which might be attributed to prolonged exposure to caries risk factors and parents control over their children s nutrition and the child s hygienic behavior decreasing as they grow up ( 12 ) . the present study was limited to cross - sectional design and all the subjects were examined from patients referring to the specialty clinic of babol faculty of dentistry . consequently , the results may not be possible to be extended to whole populations and should be interpreted cautiously . our study shows that a low level of parents ohl and living in a rural area was significantly associated with less children s dental fillings . we also found that parents unemployment was significantly related to higher children s dental caries . considering that changing families residential and economic situation seems to be impossible , improving parents ohl may be a useful alternative to promote children s dental health status . since , studies on health literacy , especially on oral health literacy are rare , it is suggested that further studies be carried out on this topic in different parts of the country , with large sample sizes and on different age groups .
introductionbecause parents play a key role in children s dental health , the aim of this study was to determine the relationship between parents oral health literacy ( ohl ) and their children s dental health status in babol , iran.methodsin this cross sectional study a total of 384 children aged 21 months to 84 months who attended the dental clinic of babol university of medical sciences between september 2015 and february 2016 were examined . 
 we measured dmft index only for primary dentition ; during examination the accompanying parent completed the  oral health literacy - adults questionnaire  . comparing mean analysis , such as one - way analysis of variance ( anova ) , and an independent - samples t - test , served to compare children s dental caries , missing , and dental fillings mean differences , between subgroups . 
 in addition , the relationship between ohl , children s dental caries , and dental fillings was assessed using multiple linear regression models while controlling for socioeconomic and demographic factors . 
 all data were analyzed by spss version 22.resultschildrens mean age was 55.1 months ( sd : 13.7 ) , while 47% were girls . 
 mean children s dental caries , missing , filling , and mean dmft index were 6.5 , 0.4 , 1.2 , and 8.2 respectively . 
 parents with inadequate ohl had children with more dental caries ( p=0.005 ) , however this relation had no significance while controlling for background factors . increasing children s dental fillings 
 was significantly related with families living in urban regions ( p=0.01 , 95% ci : 0.11 to 1.12 ) , and parents with adequate ohl ( p=0.02 , 95% ci : 0.08 to 1.05).conclusioninadequate parents ohl was associated with children having high dental caries and less dental fillings . 
 therefore , providing interventions to improve parents ohl would be valuable in children s dental health promotion programs , especially in countries with a developing oral health system .