Table 1 summarizes the characteristics of the study sample overall and by past year dental visit. Children's mean age was 9 years (range 0-17), and half were male. A quarter of the children were not born in the U.S. Most non-U.S. born children were born in Mexico (87%), and 13% were born in El Salvador (not shown). Only 14% had no dental insurance, and although 71% had Medicaid, just over half (53%) had a reported regular source of dental care. The majority (77%) of children participated in the free/reduced price lunch program.

Caregivers worked in agriculture for a mean of 111 days in the prior year. Just over one third (38%) of caregivers had a past year dental visit. Caregivers reported an average of about six years of education, but there was a wide range (0-22 years). Most families were low-income, with almost one-third reporting earning annual incomes below $10,000 supporting an average household of six individuals. The ARSMA-II acculturation scale scores indicated caregivers’ high orientation to Mexican rather than Anglo culture.

Children's clinically determined treatment need assessment indicated that 33% needed urgent care, 37% should see a dentist at their earliest convenience, while only 30% should continue their routine care. Caregivers believed 37% had cavities and 31% were unsure whether or not the child had cavities, and one quarter of the children were rated as having fair/poor oral health status. Additionally, there were several significant differences between the groups of children with and without a past year dental visit across many factors. Children with a past year dental visit were more likely to be: older, US-born, have dental insurance, have a regular dental care source, participate in the free/reduced price lunch program, and need routine care. There were differences by caregiver factors as well, and children with past year dental visits were more likely to have caregivers with a recent dental visit, higher education level, more US-oriented acculturation level, and not think the child has cavities.

Half the children had a past year dental visit. Figure 1 displays the time since last dental visit. Almost a quarter (23%) had never been to a dentist. Sixty percent of children that have never been to a dentist were age 5 or under. Although most professional provider organizations recommend the first dental visit by age one, many have not sought care, and generally, a higher proportion of younger children had never had dental care. While not included in the PEN model analyses, additional information was collected in the surveys about dental utilization in this group of children. Among the 312 children that had ever been to the dentist, almost 8% went for their first dental visit at age 1, 14% at age 2, 23% at age 3, 19% at age 4, 14% at age 5, 16% age 6-8, and 5% at age 9 or older. Among the 200 children who never had a dental visit or had not been in more than a year, 97 caregivers supplied reasons why they had not taken their child for dental care recently. The most frequent (31%) reason for not going was that the child was too young, followed by cost (16%), did not think about it (14%), no insurance (12%), no dental problem (9%), no time or no appointment (6%), fear or not wanting to take the child (6%), or other reasons (1%). Additionally, 16% of caregivers reported that there was a time in the last year that the child needed care but did not get it, suggesting there are unmet needs. Notably, about half this group includes children that did have a past year dental visit, suggesting underutilization among those that were able to seek care.

The GEE logit regression PEN Model findings are presented in Table 2. Model 3 (full model) includes all predisposing, enabling and need variables together simultaneously. No evidence of mediation was found. Nearly all significant findings from Models 1 and 2 persisted in Model 3, and enabling and need variables appear to explain some of the predisposing variables since there is some change in estimates for age, male, and non-US born. In Model 3, child's age, sex, and country of birth were significant predisposing factors, a USC and caregiver's past year dental visit were significant enabling factors, and perceptions about whether or not the child had cavities and needing treatment at earliest convenience were significant need factors. Children were less likely to have a past year dental visit if the child was male (Odds Ratio (OR)=0.55, 95% Confidence Interval (CI)=0.34-0.89, p=0.015), foreign-born (OR=0.21, CI=0.09-0.45, p<0.001), if caregiver thought child had cavities (OR=0.31, CI=0.16-0.61, p=0.001) or was unsure if child had cavities (OR=0.40, CI=0.20-0.79, p=0.008), and if child should see a dentist ‘at earliest convenience’ (OR=0.43, CI=0.23-0.80, p=0.008). Visits were about 2.5 times as likely if children were ages 6-12 years (OR=2.45, CI=1.37-4.37, p=0.002, relative to children 5 and under. Past year dental visits were also more likely if children had a USC (OR=4.78, CI=2.51-9.07, p<0.001), and if their caregivers had a past year dental visit (OR=1.87, CI 1.03-3.38, p=0.038). Whether or not children had a USC (a child-level enabling factor) had the largest impact on past year dental utilization.

A usual source of dental care was the strongest positive correlate of past year dental utilization among children in these agricultural families that should be encouraged and supported. This finding underscores the importance of obtaining a dental home for every child, an identified regular clinic or provider that can attend to all aspects of oral health for an individual (35, 40). The AAPD adapted the ideal dental home characteristics from the American Academy of Pediatrics (AAP) medical home, to include comprehensive, continuously accessible, coordinated, compassionate, culturally- effective, family-centered oral health care provided by a licensed dentist (22, 41). A dental home can have substantial clinical and financial implications for improving children's oral health; some evidence suggests that for higher risk young children, early preventive dental visits are associated with lower treatment costs and more preventive oriented utilization patterns later (42). However, for families that do not already have a dental home for their child, overcoming the many access to care barriers to establish one may only happen if financial and other major barriers begin to be addressed at the policy level.

A dental home is correlated with having a recent dental visit. However, not all children with a recent visit have a dental home. Although the relationship between a usual source of dental care and dental utilization is complex, analyses of factors relating to utilization to assess simultaneity bias by comparing models of all participants, people with a USC in the past year, and those with a source in the past 2 years found a fairly robust relationship between USC and utilization among Hispanics from San Antonio (odds ratios from 10.2-12.3; (43)). Among children in this sample with a past year dental visit, 72% had a regular source of dental care and 28% did not. It is surprising that many caregivers did not feel these children had a USC. Nearly all children without a USC went in for an exam and/or cleaning recently; only six children had a toothache or problem. Additionally, several children (34%) with a reported USC had not been to a dentist within the last year. Future studies should explore this further.

Most children in this study had dental coverage through Medicaid. However, somewhat surprisingly, the child's dental insurance status was not a key correlate in this analysis as it often is for utilization (27). This may be because of the paucity of dentists willing to accept Medicaid and see children in their practices. There were very few local dentists, not all necessarily accepted young children or had staff able to speak Spanish, and the closest pediatric dentist was about 50 miles away. For the families with a usual dentist or dental clinic for their child, most (90%) were nearby in Mendota or Fresno. Thus, many children appeared to have local dental homes. Firebaugh/Mendota is designated as a dental health professional shortage area (DHPSA) in California, according to the Office of Statewide Health Planning and Development. The Health Resources and Services Administration applies this designation when there is a 1:5000 dentist-to-population ratio or worse. While this DHSPA designation helps raise awareness of the lack of providers, and offers various programs for these areas and incentives like loan repayment to entice providers to serve there, but it is not enough. This community, and other underserved areas, would benefit from policy changes that enhance the incentives offered through these programs.

Even if there were more dentists in this area, more of them would also need to participate in the Medicaid program. California is one of the bottom ten states where children on Medicaid are least likely to have a past year dental visit, based on estimates indicating 59% did not have a visit in 2011 (44). Further, recent policy changes in California affect Medicaid and Healthy Families (the state's Children's Health Insurance Program). Children in the Healthy Families program are transitioning to Medicaid in phases during 2013, according to California Assembly Bill (AB) 1494. This means that more lower income children in California will need to seek care from Medicaid dentists. There will be a growing demand for dental care from the small network of Medicaid dental providers in the state. The state's reimbursements for services under Medicaid are low, and would likely need to be raised to attract more providers to the program.

One strategy to establish a dental home for every child may be to encourage everyone in the family to find a regular source of dental care. A regular source of care was an important positive correlate of utilization for adults in this study sample (45). Another recent study in a diverse Medicaid sample found that if Hispanic mothers had a regular source of care, their children were subsequently more likely to also utilize dental services (46). Other studies with lower income families have found similar positive effects on young children's dental utilization when caregivers get regular preventive dental care as well (47). National data also support this positive association between caregiver and child dental utilization (48). In this study, caregivers with past year dental visits had children who were almost twice as likely to have been to the dentist. Enabling caregivers to maintain regular dental care has a positive impact on child dental utilization. However, the state of California cut optional adult dental benefits on Denti-Cal (Medicaid) and the California Children's Dental Disease Prevention Program (CCDDPP) in 2009 (49), thus eliminating coverage for many adult caregivers and preventive services for children. Addressing caregivers’ dental needs will be important for improving children's oral health status in this sample as well; mothers’ untreated caries was positively associated with untreated caries in their children (50). Several costs and negative consequences associated with Medicaid adult dental benefit cuts have been documented (51). California plans to allocate funds in the next two years for select adult dental benefits under Medicaid. It will be critical to monitor the impact of these cuts on both adults and children, and in DHPSA communities in particular where there are fewer providers and access is already a challenge. Child's birth country also emerged as an important correlate of utilization. Children not born in the U.S. were far less likely to seek care. Other studies have also documented relatively lower medical and dental utilization among non-US born children (6, 20). Families may encounter significant language barriers, as many in this study were Spanish-speaking. Culturally competent providers or staff members may also be lacking; this means more than being able to speak the language. Providers may not understand the cultural values and beliefs that influence decisions to seek care.

Male children were less likely to have a past year dental visit than females in this sample. It is not clear why there was a gender difference. While not a statistically significant difference, more Mexican-American females (ages 2-17) had a past year dental visit than males (58% vs. 49%) based on 1999-2002 NHANES data (52).

Another factor to consider is the caregiver's perception of their child's need. This potential determinant of utilization may be more important for younger children that may not be as able to tell a parent when a tooth hurts. Nearly one-third of caregivers did not know whether or not their child had cavities. In one study of Latino families with preschool aged children, many caregivers believed that teeth only needed cleaning instead of treatment if they appeared stained (53). The large proportion of caregivers that did not know if the child had cavities suggests a need for more education about identifying the early signs of decay. While caregiver perceptions may not be totally accurate, it is noteworthy that 37% of caregivers thought their child had cavities. This perception was associated with a lower likelihood of a past year visit, suggesting some possible reverse causation; i.e. caregivers may know children are cavity-free because of a recent dental visit in which previously existing cavities were treated. Simply thinking the child has cavities does not in and of itself stop someone from visiting the dentist, but many parents do not think that baby teeth are important and do not visit the dentist unless a child complains of pain (53). However, in a high caries-risk population, not visiting the dentist leads to a higher chance of disease, and decreases opportunities for both caries prevention and remineralization of early lesions. Causality can not be determined in this study given its cross-sectional nature, but these caregiver perceived needs reinforce the other key finding of many unmet dental needs in this sample.

The results must be interpreted with study strengths and limitations in mind. The strengths of this analysis were the inclusion of clinical information about the child, a clinically-based treatment urgency measure of need, and caregiver-reported data from a large population-based sample of children in agricultural worker families. A full age range of 0-17 year old children was included. The limitations are that survey data are subject to recall and social desirability response biases, and as already noted, no causal relationships could be determined, and a having a USC is inter-related with having a recent visit.

The dentist-determined treatment urgency ratings indicated that the majority of children needed to see a dentist soon. Visiting a dentist within the next two weeks was recommended for 33% of the children, and another 37% were recommended to go at their earliest convenience. While this rating may be subjective, the assessments were all performed by one trained dentist and reflect a need for professional care sooner rather than later for most children.

In this population of Hispanic 0-17 year olds in agricultural worker families, many predisposing, enabling and need factors were associated with past year dental utilization. The strongest modifiable correlates were a regular source of dental care for the child and the caregivers’ past year dental utilization. Emphasis needs to be placed on these two factors to improve children's dental utilization.