BACKGROUND AND OBJECTIVE: Screening and preventive interventions by primary care providers could improve outcomes related to early childhood caries. The objective of this study was to update the 2004 US Preventive Services Task Force systematic review on prevention of caries in children younger than 5 years of age.
METHODS: Searching Medline and the Cochrane Library (through March 2013) and reference lists, we included trials and controlled observational studies on the effectiveness and harms of screening and treatments. One author extracted study characteristics and results, which were checked for accuracy by a second author. Two authors independently assessed study quality.
RESULTS: No study evaluated effects of screening by primary care providers on clinical outcomes. One good-quality cohort study found pediatrician examination associated with a sensitivity of 0.76 for identifying a child with cavities. No new trials evaluated oral fluoride supplementation. Three new randomized trials were consistent with previous studies in finding fluoride varnish more effective than no varnish (reduction in caries increment 18% to 59%). Three trials of xylitol were inconclusive regarding effects on caries. New observational studies were consistent with previous evidence showing an association between early childhood fluoride use and enamel fluorosis. Evidence on the accuracy of risk prediction instruments in primary care settings is not available.
CONCLUSIONS: There is no direct evidence that screening by primary care clinicians reduces early childhood caries. Evidence previously reviewed by the US Preventive Services Task Force found oral fluoride supplementation effective at reducing caries incidence, and new evidence supports the effectiveness of fluoride varnish in higher-risk children.
- dmfs —
- decayed, missing, or filled tooth surfaces
- OR —
- odds ratio
- USPSTF —
- US Preventive Services Task Force
Dental caries is an infectious process involving breakdown of the tooth enamel.1,2 It is the most common chronic disease of children in the United States, and is increasing in prevalence among 2- to 5-year-olds.3–5 Approximately three-quarters of children with caries have not received treatment.5
Early childhood caries is associated with pain and tooth loss, as well as impaired growth, decreased weight gain, and negative effects on speech, appearance, self-esteem, school performance, and quality of life.2,6,7 Dental caries disproportionately affects minority and economically disadvantaged children.5 Risk factors for dental caries include high levels of colonization by cariogenic bacteria, frequent exposure to dietary sugar and refined carbohydrates, inappropriate bottle feeding, low saliva flow rates, developmental defects of tooth enamel, previous caries, lack of access to dental care, low community water fluoride levels, inadequate tooth brushing or use of fluoride-containing toothpastes, lack of parental knowledge regarding oral health, and maternal risk factors, including caries, high levels of cariogenic bacteria, or poor maternal oral hygiene.4,8,9
Screening for dental caries before school entry could lead to interventions to treat existing caries at an earlier stage and prevent future caries. Young children often see a primary care medical provider starting shortly after birth, but do not see a dentist until they are older, suggesting an important primary care role for caries prevention.10,11 Access to dental care is limited by many factors, including lack of dental coverage and shortages in dentists treating young children, particularly those who are uninsured or publicly insured.12,13 Once children enter school, there are additional opportunities for screening and treatment.14
In 2004, the US Preventive Services Task Force (USPSTF) recommended that primary care clinicians prescribe dietary fluoride supplementation to children >6 months of age whose primary water source is deficient in fluoride (B recommendation).15 The USPSTF found insufficient evidence to recommend for or against primary care clinician risk assessment of +children <5 years of age for the prevention of dental disease (I recommendation). The USPSTF found no validated risk-assessment tools or algorithms for assessing dental disease risk by primary care clinicians, and little evidence on the accuracy of primary care clinicians in performing oral examinations or assessing dental caries risk.2 In addition, the USPSTF found little evidence on the effectiveness of parental education or referring children at high risk to dental care providers in reducing risk of caries and related dental disease.
Aims of This Review
This report was commissioned by the USPSTF to update its 2004 recommendation on dental caries prevention in children <5 years of age.15 With the input of members of the USPSTF, we developed an analytic framework (Fig 1) and key questions to guide our literature search and review:
How effective is oral screening (including risk assessment) by the primary care clinician in preventing dental caries in children <5 years of age?
How accurate is screening by the primary care clinician in identifying children <5 years of age who:
have cavitated or noncavitated caries lesions?
are at increased risk for future dental caries?
What are the harms of oral health screening by the primary care clinician?
How effective is parental or caregiver/guardian oral health education by the primary care clinician in preventing dental caries in children <5 years of age?
How effective is referral by a primary care clinician to a dentist in preventing dental caries in children <5 years of age?
How effective is preventive treatment (dietary fluoride supplementation, topical fluoride application, or xylitol) in preventing dental caries in children <5 years of age?
What are the harms of specific oral health interventions for prevention of dental caries in children <5 years of age (parental or caregiver/guardian oral health education, referral to a dentist, and preventive treatments)?
Key question 1 focuses on direct evidence on the effectiveness of oral screening (including oral examination and assessment of risk for future caries) by primary care clinicians in preventing future dental caries and associated complications, compared with not screening. Such direct evidence on the effectiveness of screening interventions is often limited. Therefore, the remainder of the analytic framework (key questions 2 through 7) evaluates the chain of indirect evidence needed to link screening with improvement in important health outcomes. Links in the chain of indirect evidence include the accuracy of screening to identify children with caries or at increased risk of developing caries, the effectiveness of interventions to reduce the incidence of dental caries and associated complications, and harms (including dental fluorosis) associated with screening and preventive treatments. Implicit in the indirect chain of evidence is that, to understand benefits and harms of screening, it is not sufficient to show that children at risk for dental caries can be identified; it is also necessary to show that there are effective treatments for those identified.
This review was conducted at the Pacific Northwest Evidence-Based Practice Center under contract with the Agency for Healthcare Research and Quality (Contract No. HHSA-290-2007-10057-I, Task Order No. 13), by using the systematic review methods developed by the USPSTF.16,17
We searched Ovid Medline (January 1999 to March 8, 2013) and the Cochrane Library Database (through the first quarter of 2013) for relevant articles, and reviewed reference lists for additional citations. Search strategies are shown in Supplemental Appendix 1.
Study Selection and Processes
Abstracts were selected for full-text review if they included children <5 years old (including those with caries at baseline), were relevant to a key question, and met the predefined inclusion criteria (Supplemental Appendix 2). We restricted inclusion to English-language articles and excluded studies published only as abstracts. Studies of nonhuman subjects were also excluded, and studies had to report original data.
We focused on studies of screening or diagnostic accuracy performed in primary care settings. For preventive treatments (key question 6), we also included studies of primary care–feasible treatments (treatments that could be administered or prescribed without requiring extensive dental training) performed in non–primary care settings. Treatment interventions were parental or caregiver education, referral to a dentist by a primary care clinician, and preventive treatments, including dietary fluoride supplementation, fluoride varnish, and xylitol. Interventions not commonly used or available in the United States (such as chlorhexidine varnish, povidone iodine rinses, and alternative methods for applying topical fluoride) are discussed in the full report,18 as are studies that compared different doses of xylitol. Outcomes included decreased incidence of dental caries and associated complications and harms, including dental fluorosis. Many studies reported a composite caries outcome of the presence of 1 or more decayed (noncavitated or cavitated), missing (due to caries), or filled tooth surfaces in preschool-age children.19 The abbreviation dmfs refers to decayed, missing, or filled primary tooth surfaces, and dmft refers to decayed, missing, or filled primary teeth (1 tooth may have more than 1 affected surface).
We included randomized controlled trials, nonrandomized controlled clinical trials, and cohort studies for all key questions. We also included an updated systematic review originally included in the 2004 USPSTF review of observational studies on risk of enamel fluorosis.20,21 Community interventions for prevention of dental caries and school-based interventions for older children are addressed elsewhere by the US Community Services Task Force.22
At least 2 reviewers independently evaluated each study to determine inclusion eligibility. One investigator abstracted details about each article’s study design, patient population, setting, screening method, treatment regimen, analysis, follow-up, and results. A second investigator reviewed data abstraction for accuracy.
Quality Assessment and Synthesis
Two investigators independently applied criteria developed by the USPSTF16,17 to rate the quality of each study as good, fair, or poor (Supplemental Appendix 3). Discrepancies were resolved through a consensus process. See Table 1 for a list of quality ratings for the included randomized trials. We assessed the aggregate internal validity (quality) of the body of evidence for each key question (“good,” “fair,” “poor”) using methods developed by the USPSTF, based on the number, quality, and size of studies; consistency of results among studies; and directness of evidence.16,17 Meta-analysis was not attempted because of methodological shortcomings in the studies and differences across studies in design, interventions, populations, and other factors.
Our literature search identified a total of 1215 citations, of which we reviewed 539 full-text publications and included 20 studies (Fig 2).
Benefits and Harms of Screening
No randomized trial or observational study compared clinical outcomes between children <5 years of age screened and not screened by primary care clinicians.
Accuracy of Oral Examination
One good-quality study found primary care pediatrician examination of Medicaid-eligible children <36 months of age (n = 258) after 2 hours of oral health education associated with a sensitivity of 0.76 (19/25) for identifying a child with 1 or more cavities and 0.63 (17/27) for identifying children in need of a dental referral, compared with a pediatric dentist evaluation (Supplemental Tables 5 and 6).41 Specificity was 0.95 and 0.98, respectively. The need for referral was determined by the presence of a cavity, soft tissue pathology, or evidence of tooth or mouth trauma. A study included in the 2004 USPSTF review found pediatrician examination after 4 hours of oral health education associated with a sensitivity of 1.0 and specificity of 0.87 for identifying nursing caries in children 18 to 36 months of age.42
Accuracy of Risk Assessment for Future Dental Caries
Effectiveness of Oral Health Education
No trial specifically evaluated an educational or counseling intervention by a primary care clinician to prevent dental caries. Two nonrandomized trials (1 fair quality27 and 1 poor quality24,25) found multifactorial interventions that included an educational component were associated with decreased caries outcomes in underserved children <5 years of age. Other components of the interventions included additional pediatrician training, electronic medical record reminders, and provision of tooth-brushing materials. In addition to use of a nonrandomized design, other methodological shortcomings in the poor-quality study were high attrition and failure to adjust for confounders.24,25
Effectiveness of Dental Referral
No study directly evaluated the effects of referral by a primary care clinician to a dentist on caries incidence. A fair-quality retrospective cohort study (n = 14 389) found that having a first dental preventive visit after 18 months of age in Medicaid children with existing dental disease was associated with increased risk of subsequent dental procedures compared with having a first visit before 18 months of age (incidence density ratio ranged from 1.1 to 1.4, depending on time of first dental visit, after adjusting for gender, race, number of well-child visits, and other factors), but was not designed to determine referral source.45
Effectiveness of Preventive Treatments
Dietary Fluoride Supplementation
We identified no trials published since the 2004 USPSTF review on effects of dietary fluoride supplementation in children <5 years of age. One randomized trial46 and 4 nonrandomized trials47–50 included in the 2004 USPSTF review found dietary fluoride supplementation in settings with water fluoridation levels below 0.6 ppm F associated with decreased caries incidence versus no fluoridation (percentage reduction in incidence ranged from 48% to 72% for primary teeth and 51% to 81% for primary tooth surfaces).2 In the single randomized trial (n = 140, fluoridation <0.1 ppm F), percent reductions in incidence ranged from 52% to 72% for teeth and 51% to 81% for tooth surfaces, depending on whether fluoride was given as tablets or drops.46 Two of the trials with extended follow-up also found dietary fluoride supplementation associated with decreased incidence of caries at 7 to 10 years of age (reductions ranged from 33% to 80%).47,51
Two good-quality28,31 and 1 fair-quality34 trials published since the 2004 USPSTF review evaluated fluoride varnish (2.26% F) applied every 6 months versus no fluoride varnish (Table 2). Sample sizes ranged from 280 to 1146 children. The main methodological shortcoming in the fair-quality trial was differential loss to follow-up in the treatment groups.34 The 2 good-quality trials were conducted in rural aboriginal populations in Canada (no fluoridation)28 and Australia (<0.6 ppm F for >90% of children, baseline dmfs scores of 3.8 and 11.0)31 and used a cluster design. The fair-quality trial enrolled underserved, primarily Hispanic and Chinese children in an urban United States setting with adequate fluoridation (1 ppm F) who were caries-free at baseline.34 In all studies, the fluoride varnish was applied by dental personnel.
All 3 trials found use of fluoride varnish associated with decreased caries incidence after 2 years, although the difference was not statistically significant in the Canadian study.28 Percent reductions in dmfs increment were 18% and 24% in the 2 good-quality trials,28,31 and 59% in the fair-quality trial.34 Absolute mean reductions in the number of affected surfaces ranged from 1.0 to 2.4. Results were consistent with findings from the 2004 USPSTF review, which reported a percent reduction in incident caries lesions that ranged from 37% to 63% (absolute reduction in the mean number of cavities per child of 0.67 to 1.24 per year), based on 6 trials, 2 of which were randomized.52–57
Two trials found multiple fluoride varnish applications within a 2-week period associated with no clear differences versus a standard application schedule of every 6 months,32,33 and 1 trial found no clear difference between a once versus twice yearly schedule (Table 2).34
Three trials compared xylitol to no xylitol (Table 3).29,30,35 Water was inadequately fluoridated in 1 trial30 and water fluoridation status was not reported in the other 2. The trials varied with respect to dosing and formulation of xylitol. A fair-quality randomized trial (n = 115) of children 2 years of age found xylitol tablets (0.48 g) associated with reduced dmfs increment after 2 years, but the difference was not statistically significant (mean percent reduction 52%, absolute mean reduction in affected surfaces 0.42).29 One small (n = 37) fair-quality randomized trial found xylitol wipes used 3 times per day for 1 year markedly more effective than placebo wipes in reducing caries among children aged 6 to 35 months (reduction in dmfs increment 91%, P < .05).35 A poor-quality, nonrandomized trial found no effect of xylitol chewing gum (1.33 g) 4 times daily on incidence of caries in 4-year old children in Japan.30 Xylitol was not an included intervention in the 2004 USPSTF review.
Two studies compared xylitol to topical fluoride (Table 3).23,26 A cluster randomized trial found no difference between 65% xylitol gum 3 times per day versus tooth brushing with fluoride, but was conducted in a supervised day care setting, and enrolled children up to 6 years of age, potentially limiting its applicability to younger children.26 A poor-quality trial found xylitol chewable tablets (1.2 g 3 times daily) more effective than fluoride varnish once every 6 months.23
Harms of Preventive Interventions
A systematic review included in the 2004 USPSTF review (searches conducted through September 1997) has subsequently been updated (searches conducted through June 2006).21 The update included 5 new observational studies on the association between early childhood intake of fluoride supplements and risk of fluorosis.58–62 Determinations of early childhood exposures were all based on retrospective parental recall, with fluorosis assessed at 8 to 14 years of age. Results of the new studies were consistent with the original systematic review, with intake of fluoride supplements before 7 years of age (primarily before 3 years of age) associated with increased risk of fluorosis. Risk estimates ranged from an odds ratio (OR) of 10.8 (95% confidence interval 1.9–62.0) with intake during the first 2 years of life,61 to a slight increase in risk (OR 1.1–1.7, depending on comparison).58 One study reported a dose-dependent association, with an OR of 1.8 (95% confidence interval 1.4–2.4) for each year of supplementation.62 In the prior systematic review, the ORs for dental fluorosis associated with regular early childhood use ranged from 1.3 to 10.7 in 10 studies that relied on retrospective recall and relative risks ranged from 4.2 to 15.6 in 4 studies that recorded supplement use at the time of exposure. We identified no studies published since the updated systematic review on the association between early childhood intake of dietary fluoride supplements and risk of enamel fluorosis.
No study reported the risk of fluorosis associated with use of fluoride varnish. However, the degree of systemic exposure after application of fluoride varnish is believed to be low.
As in the 2004 USPSTF review,2 we found no direct evidence on the effects of screening for dental caries by primary care clinicians in children <5 years of age versus no screening on caries incidence and related outcomes. Evidence reviewed for this update is summarized in Table 4.
New evidence was consistent with findings from the 2004 USPSTF review in showing that fluoride varnish in children <5 years of age is effective at reducing caries incidence.28,31,34 Because trials were primarily conducted in higher-risk children (based on community water fluoride levels or socioeconomic status), the applicability of these findings to children not at increased risk may be limited, particularly for studies conducted in countries and settings in which sources of fluoride and health behaviors differ markedly from the United States. In all trials, the varnish was applied by dental personnel, although fluoride varnish is considered easy to apply with minimal training.63,64
We identified no new trials on the effectiveness of dietary fluoride supplementation in children <5 years of age. Although the 2004 USPSTF review found dietary fluoride supplementation to be effective at reducing caries incidence in children <5 years of age primarily in settings with water fluoridation levels <0.6 ppm F, conclusions were mostly based on nonrandomized trials.2 Newer observational studies were consistent with the 2004 USPSTF review in finding an association between early childhood intake of dietary fluoride supplementation and risk of enamel fluorosis.21 Risk of enamel fluorosis appears to be affected by total intake of fluoride (from supplements, drinking water, other dietary sources, and dentifrices), as well as age at intake, with intake before 2 to 3 years of age appearing to confer highest risk.65 Although the prevalence of enamel fluorosis has increased in the United States, severe fluorosis is uncommon, with a prevalence of <1%.66–68
Trials of xylitol in children <5 years of age found no clear effects on caries incidence, although studies differed in the doses and formulations evaluated.29,30,35 The most promising results were from a small trial of xylitol wipes that reported a marked decrease in caries incidence, but require confirmation.35
Evidence remains limited on the accuracy of primary care clinicians in identifying caries lesions in children <5 years of age or predicting caries incidence. One study not included in the previous USPSTF review found that primary care pediatricians missed 37% of children in need of a dental referral and 24% of children with a cavity, compared with a pediatric dentist examination, although specificity was high.41 No study evaluated the diagnostic accuracy of caries risk assessment instruments administered by primary care clinicians, despite the availability of instruments designed for use in primary care settings.43 Some studies have assessed caries risk assessment instruments in children younger than 5 years of age, but the instruments were not administered by primary care providers or in primary care settings. These instruments often incorporate findings from an oral examination by dental personnel, and include tests not commonly obtained in primary care (such as mutans streptococci levels, saliva secretion level, or saliva buffer capacity),69,70 likely limiting their applicability to primary care settings.71,72
No trial specifically evaluated the effectiveness of parental or caregiver education on caries outcomes, although limited evidence from 2 trials suggests that multifactorial interventions that included an educational component could be effective.12,24,25,27, Although some evidence indicates that health care providers’ recommendation for dental care increases the likelihood of subsequent dental visits in young children,12 no trial directly evaluated the effectiveness of primary care referral to a dentist on caries outcomes, although 1 retrospective cohort study suggests that earlier dental care (before 18 months of age) is associated with fewer subsequent dental procedures in children with dental disease at baseline.45
Our review has some limitations. We excluded non–English language articles, which could result in language bias, although we did not identify non–English language studies otherwise meeting inclusion criteria. We did not search for studies published only as abstracts and could not formally assess for publication bias with graphical or statistical methods because of small numbers of studies for each key question and differences in study design, populations, and outcomes assessed. We found few or no randomized trials for a number of key questions. Therefore, we included nonrandomized trials, as well as observational studies (for harms), which are more susceptible to bias and confounding than are well-conducted randomized trials.
Research is needed to identify effective oral health educational and counseling interventions for parents and caregivers of young children. Research is also needed to validate the accuracy and utility of caries risk assessment instruments for use in primary care settings, and to determine how referral by primary care physicians of young children for dental care affects caries outcomes.
Dental caries is common in young children, many of whom do not receive dental care. Dietary fluoride supplementation and fluoride varnish are primary care–feasible interventions that appear to be effective at preventing caries outcomes in higher-risk children. Dietary fluoride supplementation in early childhood is associated with risk of enamel fluorosis, which is usually mild. More research is needed to understand the accuracy of oral health examination and caries risk assessment by primary care providers, effectiveness of primary care referral for dental care, and effective parental and caregiver educational and counseling interventions.
The authors thank the responsible medical officer at the Agency of Healthcare Research and Quality, Aileen Buckler, MD, MPH; and US Preventive Services Task Force members Linda Baumann, PhD, RN, Adelita Cantu, PhD, RN, David Grossman, MD, MPH, Glenn Flores, MD, and Virginia Moyer, MD, MPH. We also thank Andrew Hamilton, MLS, MS, for assistance with literature searches and Amanda Brunton, BS, for assistance with preparing this article.
- Accepted May 16, 2013.
- Address correspondence to Roger Chou, MD, Pacific Northwest Evidence-Based Practice Center, Oregon Health & Science University, Mail Code: BICC, 3181 SW Sam Jackson Park Rd, Portland, OR 97239. E-mail:
All authors made substantial contributions to conception and design, acquisition of data, and analysis and interpretation of data, and gave final approval of the version to be published. Dr Chou drafted the article and revised it critically for important intellectual content. He is guarantor for this article. Drs Cantor, Zakher, Mitchell, and Pappas revised the article critically for important intellectual content.
FINANCIAL DISCLOSURE: The authors have indicated they have no financial relationships relevant to this article to disclose.
FUNDING: Supported by the Agency for Healthcare Research and Quality (AHRQ) for the US Preventive Services Task Force under Contract No. 290-2007-10057-I to support the work of the USPSTF. Staff at AHRQ and members of the USPSTF developed the scope of the work and reviewed draft manuscripts. Approval from AHRQ was required before the manuscript was submitted for publication, but the authors are solely responsible for the content and the decision to submit it for publication.
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- Copyright © 2013 by the American Academy of Pediatrics