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To examine the relationship between preventive well baby visits (WBV) and the timing of first dental examinations for young Medicaid-enrolled children.
The study focused on children born in 2000 and enrolled continuously in the Iowa Medicaid Program from birth to age 41 months (N=6,322). The main predictor variables were number and timing of WBV. The outcome variable was timing of first dental examinations. We used survival analysis to evaluate these relationships.
Children with more WBV between ages 1–2 and ages 2–3 were 2.96 and 1.25 times as likely to have earlier first dental examinations as children with fewer WBV. The number of WBV before age 1 and the timing of the WBV were not significantly related to the outcome.
The number of WBV from ages 1–3 was significantly related to earlier first dental examinations, while the number of WBV before age 1 and the timing of WBV were not. Future interventions and policies should actively promote first dental examinations by age 12 months at WBV that take place during the first year of life.
The 2011 Institute of Medicine report Improving Access to Oral Health Care for Vulnerable and Underserved Populations highlights the persisting disparities in dental care access that affect young children.1 Less than 5% of children have a dental examination by age 12 months as recommended by the American Academy of Pediatrics and the American Academy of Pediatric Dentistry.2–5 A cornerstone in prevention, dental examinations provide dentists the opportunity to deliver risk-based anticipatory guidance to caregivers, allow for less invasive restorative interventions when disease is already present, and are a source of preventive care provided throughout childhood.6–7
Dental examinations are part of a comprehensive strategy to prevent early childhood caries (ECC), a type of tooth decay that affects children under age 6 years.8 ECC is the most common pediatric disease in the U.S. and is a public health problem that disproportionately affects low-income children.9–11 There was a 70% increase in the prevalence of untreated ECC among low-income children ages 2–5 years between 1988–1994 and 1999–2004.12 Thus, ECC is a growing problem. Untreated ECC can lead to pain, infection, hospitalization, and in rare cases death13–15 and is associated with subsequent tooth decay in the permanent teeth, poor school attendance, and low quality of life–consequences that have deleterious effects throughout the life course.16–18
From a public health perspective, earlier first dental examinations are likely to help prevent ECC among low-income children enrolled in state Medicaid programs.19 One study reported that earlier first dental examinations for Medicaid-enrolled children reduce the need for invasive restorative treatments and are cost effective.2 The barriers to early first dental examinations including dentists’ unwillingness to treat young children, limited caregiver knowledge on when to take their child to a dentist, medical provider uncertainty on when to refer young children, and low Medicaid reimbursement.20–22
Even though few children have a first dental examination by age 12 months, most have multiple well baby visits (WBV) by this age.23 Previous studies report associations between preventive medical and dental care use as well as use of preventive medical care and the timing of first dental visits for Medicaid-enrolled children ages 3–8.24–26 However, no study has focused on the relationship between WBV and first dental examinations for young Medicaid-enrolled children under age 3, with an emphasis on how the frequency and timing of WBV are related to the timing of first dental examinations.
In this study, we adapted a sociocultural oral health disparities model presented by Patrick and colleagues27 to test three hypotheses: 1) young children with more WBV are more likely to have earlier first dental examinations than those with fewer WBV; 2) young children with earlier first WBV are more likely to have earlier first dental examinations; and 3) other social and behavioral factors are associated with earlier first dental examinations. We focused on WBV because of the conceptual link between medical and dental care use.24–26 These first two hypotheses are based on the premise that WBV are proxies for health-related behaviors and beliefs influenced by the “motivations, values, and personal preferences” for earlier first dental examinations by caregivers.27 The third hypothesis is based on the premise that factors at the system-, community-, and family-level make up the milieu in which decisions are made by caregivers to seek dental care for their child.27 The information gleaned from this study could help identify specific points in the WBV periodicity schedule at which future population-based interventions aimed at getting infants to the dentists earlier for their first dental examination could be implemented.
This was a retrospective cohort study based on Iowa Medicaid enrollment and claims data (2000–2008) and was approved by the University of Iowa Institutional Review Board.
There were 14,364 children born in calendar year 2000 and who were enrolled in Iowa Medicaid at birth. We excluded 7,611 children who were enrolled <41 continuous months to allow for complete identification of each of the 10 recommended WBV (see Main Predictor Variables section). In addition, we excluded 133 children who received dental care from a community health center to focus on children seen in private practice clinics. Because our interest was on prevention-oriented dental examinations rather than treatment-driven visits, we also excluded children who received any restorative dental care prior to the first examination (n=170) and those who received restorative dental care but no examination (n=128). The final study population focused on children born in calendar year 2000 who were enrolled for ≥41 continuous months starting from birth and who received dental care from private practice dental clinics (N=6,322).
Model covariates were organized into five domains (Figure 1): ascribed factors (immutable individual-level variables); proximal factors (modifiable individual-level variables); immediate factors (household-level mediators between proximal and intermediate variables); intermediate factors (community-level variables); and distal factors (system-level variables). The predictor variables and the outcome measure were conceptualized as proximal factors and reflect the hypothesized link between medical and dental care use.24–27
There were two sets of predictor variables, both of which are proximal factors: 1) the total number of WBV from birth to age 41 months (WBV frequency) by period; and 2) the age at which the first WBV took place (timing of the first WBV). WBV were identified from claims files using the following International Classification of Disease–Version 9–Clinical Modification (ICD-9-CM) and Current Procedural Terminology (CPT) Codes: V20.2,V70.0,V70.3,V70.5,V70.6,V70.8, V70.9,99381,99382,99391,99392, and 99432.28
The 2000 American Academy of Pediatrics (AAP) WBV schedule was used to assess whether a child received each of the following 10 recommended WBV (no/yes): 1 month, 2 month, 4 month, 6 month, 9 month, 12 month, 15 month, 18 month, 24 month, and 36 month.4 We calculated the age at which each WBV took place by subtracting the child’s date of birth from the WBV date of service and applied previously published age ranges around each WBV to allow flexibility on when WBV occurred.29 For example, a child who had a WBV between age 7 days and less than age 1 month was classified as having had the 1 month WBV (Table 1).
To measure WBV frequency, each WBV was classified into one of three periods based on age ranges relevant in dentistry and summed (Table 1): number of WBV before age 1 (Period 1; age at which primary incisors begin to erupt; up to 5 visits possible); number of WBV between ages 1–2 (Period 2; age at which primary molars begin to erupt; up to 3 possible visits); and number of WBV between ages 2–3 (Period 3; age at which all primary teeth have erupted; up to 2 visits possible).
The timing of the first WBV consisted of two variables: 1) whether the first WBV took place by time t (a time-dependent indicator variable); and 2) the interaction between (1) and the exact age (in days) at which the first WBV took place.
The main outcome measure, a proximal factor, was the timing of the child’s first dental examination measured as the first prevention-oriented dental examination. We used the following American Dental Association Current Dental Terminology Codes to identify dental examinations from the claims files: D0150 (comprehensive dental examination) or D0120 (periodic dental examination).30 A D0120 code was included because some dentists use this to code young childrens’ first dental examination rather than the more appropriate D0150.
We used survival analysis to test our study hypotheses. Data were censored for children with no examination by age 41 months, the end of the study period. For the survival analyses, children were part of the risk set until their first dental examination. Before running our regression models, we evaluated the proportional hazards assumption using time-dependent covariates in the form of (covariate*[log(time)−mean log(time)]).35 For any variable that violated this assumption, both the main effect and time-dependent covariate was included in the model. We ran three multiple variable Cox proportional hazards regression models (α=0.05) that included the following as time-dependent variables: (1) WBV frequency across three periods; (2) timing of the first WBV; or (3) both WBV frequency and the timing of the first WBV. Because there were no differences across the models, we reported hazard ratios and 95% confidence intervals from model (3). All analyses were completed using SAS 9.3 (Cary, NC).
There were near equal proportions of males and females in our study (49.5% and 50.5%, respectively) (Table 2). Most children were White (76.6%), 20.2% were non-White, and 3.2% had unknown or missing race/ethnicity. About one-in-three children were at risk for developing a chronic condition and 2.1% were enrolled in Medicaid through the SSI Program. Only 5.8% of children saw the same medical provider for WBV. Nearly 16% of children had a mother who utilized preventive dental care prenatally. Finally, 55.5% of children lived in a metropolitan area and 65.5% lived in a dHPSA.
All children had at least one WBV during the first 41 months of life. The 2nd month WBV was the most frequently received WBV (85.6%) and the 36th month WBV was the least frequently received (41.7%) (data not shown).
In terms of WBV frequency, 55.1% of children had four or five WBV in Period 1, 64.7% had two or three WBV in Period 2, and 74.3% had one or two WBV in Period 3 (data not shown). As for the timing of the first WBV, 57.1% of children had their first WBV by age 30 days and 24.8% between ages 31 days and 60 days. The remaining 18.1% of children had their first WBV after age 61 days but before age 42 months.
Less than 2% of children had a first dental examination by age 12 months and about 25% had an examination before age 3 (data not shown). About 10% of children had their first dental examination between after age 3 but before age 41 months and 35% had an examination after age 41 months. Nearly 30% of children had no first dental examination.
Two variables–the number of WBV in Period 2 and whether the child saw different medical providers for WBV–violated the proportional hazards assumption (P=0.01 and P=0.01, respectively). Thus, the main effect and time-dependent forms of both covariates were included in the regression models.
Children with more WBV in Period 2 (between ages 1–2) and Period 3 (between ages 2–3) were 2.96 and 1.25 times as likely to have earlier first dental examinations (Table 3). WBV frequency in Period 1 (between birth and age 1) and the timing of first WBV were not related to the timing of examinations.
Three other model covariates were significantly related to earlier first dental examinations: non-White race, whether the child saw different medical providers for WBV, and whether the child’s mother utilized preventive dental care prenatally. Non-White children were 1.14 times as likely to have earlier first dental examinations as White children (P=0.02) whereas those who saw different medical providers for WBV were less likely to have earlier examinations (hazard ratio: 0.10; P=0.001). Children whose mothers utilized preventive dental care prenatally were 1.40 times as likely to have an earlier examination as children whose mothers did not (P<0.0001).
This is the first study, to our knowledge, that examined the relationship between the frequency and timing of well baby visits (WBV) and the timing of first dental examinations for Medicaid-enrolled preschool aged children. There are three main findings.
First, we tested the hypothesis that children with more WBV during three periods of early childhood would have earlier first dental examinations. More WBV only between ages 1–2 and 2–3 was significantly associated with earlier examinations. These findings are consistent with previous work suggesting significant relationships between preventive medical and preventive dental care use24,25 and first preventive dental visits26 for Medicaid-enrolled children. Conversely, the number of WBV received before age 1 was not significant. There are three explanations. First, primary (baby) molar teeth begin erupting around age 1, which may also be the time when physicians begin to introduce the importance of dental examinations to caregivers.36 Second, mothers may be more receptive to the message of first dental visits after children have more of their teeth. Third, it takes time for dental disease to manifest clinically. The period after age 1 is when physicians may first detect dental disease, at which time dental referrals for treatment become necessary.
Second, we tested the hypothesis that children with earlier first WBV would also have earlier first dental examinations. We found that the timing of the first WBV was not related to the timing of first examinations. Although this is a conceptually relevant variable, the reason it failed to reach statistical significance in our model may be related to low variance. Over 90% of children had their first WBV by age 3 months and 99% had their first WBV by age 11 months.
Third, we tested the hypothesis that other social and behavioral factors would be related to the timing of first dental examinations and we identified three important factors. First, non-White children were significantly more likely to have earlier first dental examinations than White children. Previous studies suggest race- and ethnicity-based variation in dental care use.31,37,38 Earlier first dental examinations for non-White children may indicate greater levels of dental disease and caregiver motivation to take their child to the dentist, though this interpretation requires verification in a future study. Second, children who saw the same medical provider for WBV had significantly earlier first dental examinations, which suggests additional benefits associated with having a usual source of medical care.37 Seeing the same medical provider increases the likelihood of consistent anticipatory guidance and may facilitate enhanced communication between caregivers and pediatricians.33,39 Third, children whose mothers utilized preventive dental care prenatally were significantly more likely to have earlier examinations. A possible explanation is these mothers may learn about the importance of infant oral health from their dentist. However, knowledge gaps among dentists make this unlikely.40–42 A more plausible explanation is that these caregivers have higher levels of health literacy and a stronger preference for oral health43,44, which translate into prevention-oriented health behaviors and earlier first dental examinations for their children. This finding is consistent with previous work linking mother and child dental care use34 and supports policies aimed at ensuring dental homes for mothers both prenatally and postnatally.
In regards to our conceptual model, it appears that one proximal factor (whether the child saw different medical providers for WBV) and one immediate factor (whether the child’s mother used preventive dental care) were related to the timing of first dental examinations. There were no significant differences across the intermediate factor (rurality) and the distal factor (living in a dental Health Professional Shortage Area). These findings suggest that the determinants of the timing of first dental examinations for young Medicaid-enrolled children are influenced by child- and family-level factors rather than upstream community- and system-level factors. The potentially modifying role of upstream factors such as rurality and living in a dental Health Professional Shortage Area should be examined in future studies.
Our findings are relevant in developing and improving medical office-based interventions aimed at reducing oral health disparities in young children, such as North Carolina’s Into the Mouth of Babes Program.45 Because children are more likely to visit a physician for preventive care than a dentist by age 12 months, WBV are a point of intervention to train physicians and nurses to recommend first dental examinations for all children by age 12 months. Formal partnerships between medical and dental offices may facilitate the referral process and allow medical office personnel to follow up with dentist referrals. In areas with dentist shortages or waiting lists for dental appointments, oral health screenings and direct preventive care in the form of fluoride varnish by physicians may be the only care children receive until the child is seen by a dentist. While 46 state Medicaid programs reimburse physicians for applying fluoride varnish46, Medicaid reimbursements alone are not likely to incentivize medical offices to participate in formal oral health prevention programs.47 Medical office-based preventive interventions should incorporate intensive training to help medical providers overcome knowledge barriers and increase their confidence in providing oral health-related anticipatory guidance.21,48
There are four main limitations with our study. The first is that our findings are only generalizable for children continuously enrolled in Medicaid from birth to age 41 months. The relationship between WBV and first dental examinations or children who are intermittently enrolled in Medicaid may be different. The second is the potential for selection bias. Caregivers whose children have more WBV may have stronger preferences for oral health and health in general, which may induce a non-causal correlation between WBV and dental examinations. Unobserved child health factors may also confound this relationship. Future studies should collect data from caregivers to account for other potentially important behavioral factors (e.g., perceived severity of dental disease, self-efficacy of obtaining care) associated with earlier first dental examinations. Instrumental variable and propensity score analytic methods may address selection, though both approaches have limitations that require careful consideration.49–52 Furthermore, there is a need to include additional covariates from the distal, intermediate, and immediate domains. Third, children with earlier examinations may already have dental disease when they initially present at the dentist. In other words, disease rather than prevention may be a driver of earlier first examinations, which conflicts with a primary prevention model. However, less than 2% of children in our study received restorative treatment on the same date as the first dental examination. In the future, clinical dental data would help to identify the potential modifying role of disease. Fourth, the analyses were based on children born in 2000, which gives us a baseline perspective on how WBV are related to first dental examinations. The AAP and Bright Futures began recommending in 2000 and 2007, respectively, that physicians assess a child’s oral health risk starting at age 6 months.4,53 Examining the relationship between WBV and first examinations over time may reveal how changes in clinical guidelines impact childrens’ dental care use.
Oral health is an integral part of the overall health and well being of young children. But few children see a dentist by age 12 months, which motivates efforts to identify the factors related to earlier first dental examinations. In our study, more WBV between ages 1–2 and 2–3 years were significantly associated with earlier first dental examinations. While this provides additional evidence for a relationship between preventive medical and dental care use, this finding is cause for concern because these WBV occur past the recommended age at first dental examination of 12 months. In fact, only 2% of children in our study had an examination by age 12 months and less than one-in-four children had an examination by age 3. It is most worrisome that 30% of Medicaid-enrolled children had no examination even though all of these children had at least one WBV and 97.3% had more than one WBV. Earlier first dental examinations are not a panacea for disparities in oral health. However, they play an important role in ensuring optimal oral health for young children. Additional research is needed to further understand the relationship between WBV and first dental examinations with an emphasis on identifying the behavioral and social determinants of first dental examinations and uncovering the mechanisms that drive these relationships. This knowledge can then be used to develop appropriate clinical and policy solutions aimed at optimizing the oral health of all young children.
This study was supported by the National Institute of Dental and Craniofacial Research (NIDCR) Grants RC1DE020303 and K08DE020856. We would like to thank the Iowa Department of Human Services for access to Medicaid data; Mr. Rusty Heckaman, Archivist at the American Academy of Pediatrics, for providing historical documents on preventive pediatric health care recommendations; and Dr. John Neff, Professor of Pediatrics at the University of Washington School of Medicine, for his help with operationalizing study variables. Portions of this study were presented at the International Association of Dental Research (IADR) Meeting in San Diego, CA in March 2011 and the National Oral Health Conference in Milwaukee, WI in May 2012.
Human Participant Protection
This study protocol was approved by the institutional review board at the University of Iowa.
ContributorsD.L. Chi conceptualized the study, synthesized the analysis plan, analyzed the data, and led the writing of the article. E.T. Momany assembled the data sets and assisted with writing the article. M.P. Jones assisted with conceptualizing study variables and the data analyses. R.A. Kuthy assisted with study conceptualization and with writing the article. N.M. Askelson assisted with study conceptualization and with writing the article. G.L. Wehby assisted with study conceptualization and with writing the article. P.C. Damiano helped synthesize the analysis plan and assisted with writing the article. All authors helped to refine the final study design, interpret findings, and review drafts of the article.