Global situation of oral health coverage toward universal health coverage: A scoping review

Abstract

Objective

This study investigates the status of Universal Health Coverage in oral/dental services from the perspectives of population, service, and cost coverage, as well as other aspects of financing, using a scoping review.

Method

A scoping review of published articles from 2000 to 2024 was conducted, utilizing scientific databases including PubMed, Scopus, Web of Science, Embase, and ProQuest, along with other sources such as grey literature and Google Scholar.

Result

The initial search identified 58,778 articles, with 28 articles included in the final analysis after screening and full-text review. The included countries were Australia, Bulgaria, Canada, China, Finland, France, Germany, Greece, India, Iran, Ireland, Italy, Japan, Netherlands, Poland, Romania, Spain, Sudan, Sweden, Thailand, Turkey, United Kingdom, Ukraine, and the United States. The condition of oral health coverage was reported by factors such as dental health expenditure, coverage type, service and cost coverage, coverage of age/specific groups, and cost sharing.

Conclusion

Dental services are mainly provided by the private sector, do not have adequate public coverage and are mainly financed by out-of-pocket payments. However, Dental health expenditure and coverage vary significantly across countries, influenced by diverse healthcare systems, economic conditions, and public health priorities. Countries like Sweden and the United Kingdom demonstrate strong public funding commitments, providing comprehensive coverage for preventive and basic services. In contrast, countries like Australia and the United States rely more on private insurance, leading to higher out-of-pocket costs for individuals. Addressing high out-of-pocket payments and ensuring equitable access to oral health care remain key challenges.

Highlights

• •There are significant disparities between countries in terms of Universal Health Coverage in oral health.
• •In most of the countries, dental services do not have adequate universal coverage.
• •Oral health services are mainly financed by out-of-pocket payments.
• •The primary solution is to increase the share of public sources in oral health financing.
• •Ensuring access and addressing gaps in coverage for all sub-populations, is essential.

1. Introduction

Oral and dental diseases represent a significant global public health challenge due to their high prevalence, disproportionate impact on marginalized populations, and substantial economic consequences. These conditions—including dental caries, periodontal disease, tooth loss and oral cancers—affect nearly 3.5 billion people worldwide. Dental caries alone impacts ∼2.5 billion people, while severe periodontal disease affects ∼ one billion, and complete tooth loss impacts ∼350 million individuals (Peres et al., 2019a; Collaborators et al., 2020; Organization WH, 2022; Jain et al., 2024). Beyond physical suffering (e.g., pain, functional impairment), oral diseases reduce quality of life through economic hardship (e.g., lost productivity), social stigma, and psychological distress (Hugo et al., 2021; Winkelmann et al., 2022a).

Oral health conditions represent a significant global public health challenge, affecting nearly 3.5 billion people worldwide (World Health Organization, 2022). The Global Burden of Disease Study (2019) documents that untreated dental caries remain the most prevalent health condition globally, while severe periodontitis affects one billion people. The World Health Organization's Global Oral Health Action Plan (2023) emphasizes that oral diseases disproportionately affect vulnerable populations, with marginalized groups experiencing two-three times higher prevalence rates. In low-and-middle-income countries, approximately 90 % of caries cases remain untreated, compared to 30–50 % in high-income countries (Collaborators et al., 2020; Organization WH, 2022; Peres et al., 2019b; Eaton et al., 2023).

Addressing oral health is critical not only for individual well-being but also for reducing systemic inequities and alleviating strain on healthcare systems. However, access to oral health care remains highly unequal, particularly in low-and-middle-income countries, where weak health infrastructure, limited public financing, and high out-of-pocket \ expenditures create barriers (Winkelmann et al., 2022a; Serapioni and Hespanha, 2019; Jevdjevic et al., 2021). In high-income countries, disparities persist among low-income households, rural communities, and racial/ethnic minorities. For example, in Organization for Economic Co-operation and Development nations, oral health care accounts for ∼20 % of total health out-of-pocket spending, with reporting 97 % of dental expenditures paid out-of-pocket. Such costs can lead to catastrophic health expenditures (Winkelmann et al., 2022a; Serapioni and Hespanha, 2019; Jevdjevic et al., 2021; Proaño et al., 2024; Sayuti and Sukeri, 2022; Taylor et al., 2021). Universal health coverage, aligned with Sustainable Development Goals 3.8, aims to ensure equitable access to health services without financial hardship and, by extension, improving health outcomes—though further research is needed to clarify the causal relationships between oral health coverage and overall well-being.

The World Health Organization framework for universal health coverage delineates three interdependent dimensions of coverage. Population coverage refers to the proportion of individuals entitled to publicly funded or subsidized oral health care, distinguishing legal entitlement from contextual access barriers. Service coverage encompasses the range of included treatments, spanning preventive interventions through complex restorative procedures. Cost coverage constitutes the financial protection mechanisms, including co-payment structures, exemption policies, and catastrophic expenditure safeguards. These dimensions collectively determine the equity and comprehensiveness of dental health systems (Jain et al., 2024; Sayuti and Sukeri, 2022; Taylor et al., 2021; Bhoopathi et al., 2020; Winkelmann et al., 2022b).

Despite growing recognition in Universal health coverage frameworks, oral health is often inadequately prioritized. Only six of 24 countries comprehensive public dental coverage (Bulgaria, Finland, Germany, Poland, Spain, United Kingdom), with many excluding adults or specialized treatments. Low-and-middle-income countries frequently lack access to basic services (e.g., fillings, extractions), while high-income countries may restrict coverage to children or emergency care. World Health Organization Europe's 2021 oral health resolution highlights this gap, urging integration of oral health into primary care and expanded preventive measures (Collaborators et al., 2020; Organization WH, 2022; Jain et al., 2024; Winkelmann et al., 2022b; Henschke et al., 2023).

This scoping review examines global disparities in dental service coverage across Population coverage: Eligibility criteria and inequities (e.g., rural vs. urban), Service coverage: Included treatments (e.g., preventive, surgical), Cost coverage: out-of-pocket burdens and catastrophic health expenditures risks and Financing mechanisms: Public vs. private models (e.g., insurance, taxation).

2. Methods and materials

2.1. Study design

This scoping review assessed global dental service coverage within Universal health coverage frameworks, focusing on population coverage, service coverage, and cost coverage (defined below). We followed the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) guidelines.

2.2. Search strategy

Databases are PubMed, Scopus, Web of Science, Embase, ProQuest, and grey literature (Google Scholar, World Health Organization / Organization for Economic Co-operation and Development reports, government policy documents). Google Scholar screened the first 50 pages (500 results) per search term, prioritized by relevance. Policy documents Sourced from World Health Organization / Organization for Economic Co-operation and Development reports and government websites of 35 countries (prioritizing those with Universal health coverage monitoring reports: e.g., United Kingdom National Health Service, The French National Authority for Health, Thailand's Universal Coverage Scheme, Ghana's National Health Insurance Scheme). Timeframe were 2000–2024 to capture both long-term trends and post-pandemic reforms (e.g., Spain's 2022 dental coverage expansion). Terms were combined keywords (PubMed MeSH and free-text) for Coverage: “Insurance Coverage”[Mesh], “Universal Health Coverage,” “Entitlement”, Services: “Dental Health Services”[Mesh], “Preventive Dentistry,” “Basic/Comprehensive Oral health care” & Costs: “Out-of-pocket expenditures,” “Catastrophic Health Expenditure,” “Dental Financing” (catastrophic health expenditures specifically captured dental spending where disaggregated) (defined in Table 1.) Filters were English language and quantitative studies. Validation was Peer-reviewed using the Peer Review of Electronic Search Strategies checklist; refined iteratively with a librarian.

Table 1.

Oral health financing indices across 24 countries (2000–2024): per capita spending, Gross Domestic Product share, government health budget share, and patient cost-sharing mechanisms in time frame (2000–2024).^⁎

Study	Country	Per Capita Expenditure	% of Gross Domestic Product / Gross National Product	% of Health Expenditure / Budget	Cost Coverage & Cost Sharing
(Srivastava et al., 2017)	Australia	–	–	5 % of health Expenditure	56.8 % out-of-pocket, 15.1 % private insurance, 6.3 % Government rebates, 21.3 % other Government
(Peeva, 2019)	Bulgaria	–	–	–	2.8 Lev (€1.4) per visit +40 % co-pay
(Bhatti et al., 2007; Neumann and Quiñonez, 2014; Locker et al., 2011)	Canada	$309	0.8	7.4 % of health Expenditure	50 % reimbursement for major procedures, deductible applies
(Qu et al., 2020)	China	–	–	–	Global Medical Insurance: 90–95 %, Urban Employee Basic Medical Insurance: 60–75 %, Urban Resident Basic Medical Insurance: 50–65 % reimbursement
(Niiranen et al., 2008)	Finland	€135	–	–	Patients' share decreased from 55 % to 49 % (2000–2004)
(Neumann and Quiñonez, 2014; Pegon-Machat et al., 2016; Sinclair et al., 2019)	France	€152	0.5	5.7 % of health Expenditure	70 % fixed fee coverage, 100 % for chronic conditions
(Henschke et al., 2023; Sinclair et al., 2019; Ziller et al., 2015)	Germany	€276	0.7 % Gross National Product	–	100 % basic services, 80 % orthodontics (children)
(Sinclair et al., 2019; Damaskinos et al., 2016)	Greece	€135	1.1 % Gross National Product	–	Up to 20 % co-pay in private insurance
(Shah, 2004)	India	–	–	–	Deductibles, coinsurance, low coverage caps
(Khoshnevisan et al., 2018)	Iran	–	–	–	Private financing mostly out-of-pocket, coinsurance and cap payment in some social health insurance and supplementary schemes
(Woods et al., 2017)	Ireland	–	–	3.2 % of health Expenditure	82.6 % out-of-pocket, was 20 % co-pay until 2009
(Sinclair et al., 2019; Bindi et al., 2017)	Italy	€250	0.82 % Gross National Product	–	€66 co-pay per 8 prescriptions
(Zaitsu et al., 2018)	Japan				30 % patient co-pay, reimbursement for high costs
(Henschke et al., 2023; den Boer et al., 2020)	Netherlands	–	0.32–0.42 %	–	18.9 % outpatient care coverage
(Sinclair et al., 2019; Malkiewicz et al., 2016)	Poland	–	–	2.7 % of health budget	2.7 % of healthcare budget (2014)
(Sinclair et al., 2019; Oancea et al., 2016)	Romania	–	–	€14 M public funding	90 % out-of-pocket, 60 % coverage for some adult treatments
(Henschke et al., 2023; Sinclair et al., 2019; Bravo et al., 2015)	Spain	€102	–	–	97.2 % outpatient care coverage
(Lamloum and Campus, 2024)	Sudan	$330	1 %	–	Annual £SG14–28 support, 50–85 % high-cost protection
(Sinclair et al., 2019; Pälvärinne et al., 2018)	Sweden	€460	–	–	National Health Service co-pay bands, private variable
(Srimuang and Pholphirul, 2022)	Thailand	–	–	–	User fees in state practices
(Ekici et al., 2017)	Turkey	–	–	4.8–5.3 % of health budget	40 % uninsured, Medicaid co-pays in 21 states
(Neumann and Quiñonez, 2014; Sinclair et al., 2019)	United Kingdom ⁎	€145	0.6	4.1 % of health Expenditure	46 % public financing, 54 % private financing (75 % out-of-pocket, 25 % private insurance)
(Bindi et al., 2012)	Ukraine	–	–	1.4 % of health Expenditure	56.8 % out-of-pocket, 15.1 % private insurance, 6.3 % Government rebates, 21.3 % other Government
(Neumann and Quiñonez, 2014; Manski et al., 2014; Kaylor et al., 2011)	United States	$348	0.7	4 % of health Expenditure	2.8 $ per visit +40 % co-pay

1. Covers an examination, diagnosis (including X-rays), advice on how to prevent future problems, a scale and polish if needed, and preventive care such as the application of fluoride varnish or fissure sealant. Cost: £23.80.

2. Covers everything in Band 1, plus any further treatment such as fillings, root canal work, or extractions. Cost: £65.20.

3. Covers everything in Bands 1 and 2, plus more complex procedures such as crowns, dentures, and bridges. Cost: £282.80.

^⁎United Kingdom; The National Health Service dental charges are divided into three bands: 1. Covers an examination, diagnosis (including X-rays), advice on how to prevent future problems, a scale and polish if needed, and preventive care such as the application of fluoride varnish or fissure sealant. Cost: £23.80. 2. Covers everything in Band 1, plus any further treatment such as fillings, root canal work, or extractions. Cost: £65.20. 3. Covers everything in Bands 1 and 2, plus more complex procedures such as crowns, dentures, and bridges. Cost: £282.80.

2.3. Eligibility criteria

The review employed dual inclusion criteria: studies reporting quantifiable national or regional dental coverage policies, expenditure data, or insurance structures; and grey literature with verifiable metrics from authoritative sources. Exclusion criteria eliminated studies without dental-specific coverage disaggregation (e.g., general health insurance lacking oral health differentiation) and non-empirical commentary pieces.

2.4. Screening & data extraction

During the pilot phase, two independent reviewers screened 5 % of the identified articles to assess inter-rater reliability. A kappa score greater than 0.8 was obtained, indicating strong agreement between reviewers. Following this initial assessment, full-text screening was conducted independently by the same two reviewers. Any discrepancies that arose during the screening process were resolved through discussion and consensus, with 100 % agreement achieved without the need for a third reviewer. No study authors were contacted for missing data, as all necessary information was successfully extracted from published sources.

Data extraction was carried out using a spreadsheet template designed to capture key variables systematically. These included population coverage, defined as the percentage of the population eligible for publicly funded or subsidized dental care; service coverage, categorized into basic services (such as examinations, fillings, and extractions) and comprehensive services (including crowns, implants, and orthodontic treatments); and cost coverage, which encompassed the proportion of total dental expenditures paid out-of-pocket, as well as the incidence of catastrophic health expenditures. Catastrophic health expenditures is specifically defined as households spending more than 20 %/ 40 % of their total income/capacity to pay on dental care, with separate data extraction applied in cases where studies explicitly differentiated dental spending from general health expenditures. Additionally, data on financing mechanisms were collected, including the public-to-private funding ratio and reimbursement models used across different healthcare systems.

2.5. Synthesis

The synthesis of findings was conducted using quantitative and qualitative methods. Quantitative data were tabulated by country and region, enabling comparative analysis across different income levels and healthcare system types, as detailed in Table 2. Qualitative synthesis involved thematic analysis to identify common barriers to access, notable innovations in service delivery—such as the use of tele-dentistry in low- and middle-income countries—and the impact of the COVID-19 pandemic on dental coverage. This impact was documented where data permitted, such as in the case of temporary Medicaid expansions in the United States aimed at maintaining access during lockdown periods.

Table 2.

Population coverage for oral services by age group and vulnerability status across 20 countries: comparative analysis of pediatric, adolescent, elderly and disabled population entitlements in time frame (2000–2024).

Country	Pediatrics Coverage	Adolescent Coverage	Elderly Coverage	Disabled Coverage
Australia	Not specified	Not specified	Limited coverage	Not specified
Bulgaria	All groups (basic services)	All groups	All groups	All groups
Canada	Full public subsidies	Full public subsidies	Sharp drop after 65	Public coverage for adults
China	Urban Resident Basic Medical Insurance covered	Urban Resident Basic Medical Insurance covered	Urban Resident Basic Medical Insurance / Global Medical Insurance covered	Not specified
Finland	Free (<18)	Free (<18)	Included since 2000	Not specified
France	Free Mouth Examinations and Dental Care for Youth	‘M'T dents’ program	Long-term care included	Couverture Maladie Universelle complémentaire coverage
Germany	Full coverage (<18)	Full coverage	Partial coverage	Special programs
Greece	Free 6–12 years	Not specified	Not specified	Not specified
India	Not specified	Not specified	Not specified	Not specified
Iran	Free <14 years for primary care	Plans to 18 years for public services	Not specified	Not specified
Ireland	Free <16	Free <16	Medical cards >66	Public Dental Service coverage
Italy	Free 0–14	Not specified	Vulnerable only	Major health risks
Japan	Preschool exams	School programs	90 % Long-Term Care insurance coverage	Not specified
Netherlands	Full <18	Full <18	Limited	Severe disabilities
Poland	Free care	Free care	Priority status	Full treatment
Romania	Free <18	Free <18	Not specified	Contribution exempt
Spain	Free <14	Free <14	Not specified	Not specified
Sweden	Free	Free	High-cost protection	Special support
United Kingdom	Free <18/19	Free <18/19	National Health Service with co-pays	Special provisions
United States	Medicaid covered	Medicaid covered	70 % uninsured	Not specified

We used EndNote for citation management and employed the Peer Review of Electronic Search Strategies checklist to ensure the quality and comprehensiveness of our search strategy. The Peer Review of Electronic Search Strategies checklist is a structured tool designed to enhance the accuracy and efficiency of electronic literature searches through systematic peer review. No statistical software package was used.

2.6. Definitions

To ensure consistency and clarity throughout the review, key terms were clearly defined. Out-of-pocket spending was defined as direct payments made by households for dental services, excluding insurance premiums. Dental health expenditure referred to the total national spending on oral health care, combining both public and private funding sources. Cost coverage was defined as the presence and extent of financial protection mechanisms, such as co-payment caps, exemption policies, and safeguards against catastrophic health expenditures.

2.7. Ethical considerations

As a scoping review of existing published literature, this study did not involve direct interaction with human subjects or collection of primary data. All data were obtained from publicly available sources and previously published studies that had already undergone ethical review through their original institutions. Since this methodology does not constitute human subjects research, institutional review board approval was not required per standard research ethics guidelines for evidence synthesis projects.

We confirm that No original human subjects data were collected, all analyzed data were properly anonymized in their original publications, all source materials are properly cited and publicly accessible, and the study complies with ethical standards for secondary research synthesis.

This approach aligns with established protocols for scoping reviews as outlined in the Joanna Briggs Institute Reviewer's Manual and PRISMA-ScR guidelines, which do not require prospective registration or ethical approval for literature-based evidence syntheses.

3. Result

Our search identified 58,778 records across five databases. After duplicate removal (45,474 records), title/abstract screening excluded 45,296 irrelevant studies. Full-text review of 182 articles yielded 28 eligible studies (Fig. 1: PRISMA flowchart) and the time period of study was 2024-06-01 to 2024-08-01. The 24 represented countries spanned all World Bank income groups: high-income countries: Australia, Canada, France, Germany, Japan, United Kingdom, United States (n = 17), Middle-income: China, India, Iran, Thailand, Turkey (n = 7), Low-income: Sudan (n = 1). Timeframe according Pandemic was Pre-pandemic (2000–2019) with 22 studies (78.6 %) and Pandemic/Post-pandemic (2020–2024): 6 studies (21.4 %). Universal health coverage Dimension (Summarized in Table 1; full country-level data in Supplementary Table S1) of Population Coverage by high-income countries were Universal entitlement for children (e.g., United Kingdom National Health Service) but variable adult coverage (e.g., Germany = 100 % vs. United States Medicaid = 25 % eligible). low-and-middle-income countries were Limited to public-sector employees (India) or emergency care (Sudan). Service Coverage by Basic services (exams, fillings, extractions): Covered in 89 % of high-income countries vs. 29 % of low-and-middle-income countries, Comprehensive services (crowns, implants): Excluded in 71 % of low-and-middle-income countries (e.g., Thailand's Universal health coverage excludes prosthetics), and Cost Coverage, out-of-pocket expenditures Ranged from 5 % (Sweden) to 97 % (Spain) of total dental spending, Catastrophic expenditures Reported in 12 studies, primarily affecting low-and-middle-income countries households (e.g., Iran: 18 % faced catastrophic health expenditures) Table 1. The situation of health systems in terms of population coverage for dental care, oral service coverage (preventive, basic, advanced and luxury dental service), and oral health financing models across reviewed countries were shown in the Table 2, Table 3 and 4, respectively. The COVID-19 pandemic had mixed effects on global dental service coverage, with both temporary improvements and sustained setbacks. Several high-income countries implemented positive short-term reforms to maintain access during lockdowns; for example, Australia introduced temporary tele-health subsidies to facilitate remote dental consultations, particularly benefiting rural and vulnerable populations. However, these expansions were often time-limited and inconsistently adopted across health systems. Conversely, many countries experienced reduced public dental budgets due to pandemic-related economic strains. Greece suspended all non-emergency public dental services from 2020 to 2021, exacerbating preexisting treatment backlogs and disproportionately affecting low-income groups reliant on public care. Similar service reductions were observed in other nations that deprioritized oral health during health system shocks (i.e., acute disruptions to health systems from crises like pandemics). A critical limitation in assessing these impacts is the scarcity of dedicated studies: only three of the 28 reviewed publications (10.7 %) explicitly analyzed pandemic-era changes, with most data derived from broader health system analyses. This evidence gap underscores the need for targeted research on how emergency policies affected long-term dental coverage equity, particularly in low- and middle-income countries where documentation was weakest. The pandemic both exposed and amplified structural vulnerabilities in oral health systems, revealing inconsistent preparedness for health crises across income settings.

Fig. 1.

PRISMA Flow Diagram for the scoping review process.

Table 3.

Oral service coverage gradients by treatment complexity in 24 national health systems: preventive, basic, advanced and luxury dental service inclusion in public health plans in time frame (2000–2024).

Country	Preventive Services	Basic Services	Advanced Services	Luxury Services
Australia	Limited	Emergency/general treatment	Not covered	Not covered
Bulgaria	Children's programs	Exams, fillings, extractions	Limited (out-of-pocket /private)	Not covered
Canada	Checkups, cleanings	Routine care	Partial private coverage	Not specified
China	Not covered	Urban Employee Basic Medical Insurance / Urban Resident Basic Medical Insurance / Global Medical Insurance	Not covered	Not covered
Finland	Available	Available	Not specified	Not specified
France	Free Mouth Examinations and Dental Care for Youth	Exams, extractions, fillings	Crowns, bridges (<16 orthodontic)	Implants, sedation
Germany	Cleanings, sealants	Exams, fillings, surgery	Prosthodontics grants	Not covered
Greece	Banking funds only	<18 + emergencies	Not covered	Not covered
India	Limited	Exams, fillings, extractions	Limited	Not covered
Iran	Maternal/child focus	Priority groups	Not specified	Not specified
Ireland	Public Dental Service / Dental Treatment Benefit Scheme programs	Dental Treatment Service Scheme / Dental Treatment Benefit Scheme	Orthodontics, surgery	Not specified
Italy	Hygiene services	Emergency care	Urgent cases only	Not covered
Japan	Child fluoride	Restorative, surgery	Excluded (implants, orthodontic)	Excluded
Netherlands	<18 basic insurance	<18 covered	Supplementary insurance	Not specified
Poland	Full prevention	Fillings, extractions	Youth/disabled surgery	Implants (out-of-pocket)
Romania	School programs	Annual exams	Not covered	Not covered
Spain	Sealants, education	<14 comprehensive	Adult extractions only	Not covered
Sudan	Limited	Limited	Specialized care	Not specified
Sweden	Insurance + Healthy dental care program	Full coverage	High-cost protection	Not specified
Thailand	Exams, sealants	Fillings, extractions	Root canals, dentures	Limited orthodontic
Turkey	Limited	Exams, fillings	Limited (out-of-pocket /private)	Not covered
United Kingdom	National Health Service checkups	National Health Service fillings, extractions	National Health Service complex work	Cosmetic (private)
Ukraine	Voluntary Health Insurance minimal	Emergency care	Available (out-of-pocket /private)	Not specified
United States	30.7 % procedures	42.3 % procedures	12.5 % procedures	Not covered

Table 4.

Oral health financing models across 24 countries: comparative distribution of government budget, social insurance schemes, and private insurance market penetration in time frame (2000–2024).

Country	Government Budget Coverage	Social Insurance Coverage	Private Insurance Coverage
Australia	Means-tested basic care	None	46 % population (dominant)
Bulgaria	National Health Insurance Fund managed	National Health Insurance Fund provided	Veteran Health Identification Card available
Canada	Marginalized groups only	None	62.6 % (employer-based)
China	Global Medical Insurance system	Urban Employee Basic Medical Insurance / Urban Resident Basic Medical Insurance / New Rural Cooperative Medical Scheme	Commercial insurance
Finland	Tax-funded Public Dental Service	National Health Insurance subsidies	Private providers
France	32.1 % public insurance	Statutory Health Insurance (Sécurité Sociale)	95 % use complementary
Germany	None	Statutory Health Insurance (universal)	Opt-out/additional
Greece	National Health Service /health units	National Organization For Health Care Services (employer/employee)	Major private spending
India	Central Government Health Scheme / Employees' State Insurance Scheme	Organized sector only	Emergency coverage only
Iran	Public Health Centers integration	Military/oil company schemes	Supplementary available
Ireland	Tax-funded	Pay Related Social Insurance scheme	Voluntary Health Insurance /Laya & Aviva providers
Italy	Servizio Sanitario Nazionale /military hospitals	None	Complementary available
Japan	Universal system	National health insurance	Minimal role
Netherlands	Children <18	None	Adult supplementary
Poland	Public insurance	Universal contributions	Private packages
Romania	Ministry of Health	National Health Insurance House managed	Private/public mix
Spain	Sistema Nacional de Salud managed	None	13 % population
Sweden	County/national taxes	Dental insurance (≥20y)	Growing private sector
Thailand	Universal Coverage Scheme / Social Security Scheme / Civil Servant Medical Benefit Scheme	Included in schemes	Not specified
Turkey	Ministry of Health	Social Security Institution	Private companies
United Kingdom	National Health Service funded	None	11.8 % population
United States	Medicaid (state-variable)	None	48.6 % total spending

4. Discussion

This scoping review elucidates critical disparities in dental health coverage across 24 countries, revealing how healthcare system typologies, economic conditions, and policy priorities shape oral health care accessibility. Three principal findings emerge. Divergent Investment Patterns: Public expenditure ranges from 0.32 % of Gross Domestic Product (Netherlands) to 1.1 % (Greece), with per capita spending spanning €102 (Spain in 2015) to €460 (Sweden in 2018) (Henschke et al., 2023; Bravo et al., 2015; Pälvärinne et al., 2018). Tax-based systems (e.g., United Kingdom, Sweden) provide broader coverage, while mixed systems (e.g., United States, Australia) rely on private insurance, exacerbating out-of-pocket burdens (Sinclair et al., 2019; Oancea et al., 2016). Coverage Gaps by Demographics: While 89 % of high-income countries cover pediatric preventive care, only 34 % extend comparable benefits to older adults (Manski et al., 2014). low-and-middle-income countries (e.g., India, Sudan) often restrict coverage to emergency care or formal-sector workers (Shah, 2004), reflecting systemic exclusion of vulnerable groups. Financial Protection Failures: catastrophic health expenditures disproportionately affect uninsured populations—evidenced by Spain's 97 % out-of-pocket dental costs (Bravo et al., 2015) and United States Medicaid gaps excluding 25 % of low-income adults (Taylor et al., 2021). These disparities are rooted in structural and policy-driven factors. Nations prioritizing prevention (e.g., Sweden's universally free pediatric dentistry) demonstrate lower long-term treatment costs (Pälvärinne et al., 2018), whereas low-and-middle-income countries constrained by limited health budgets (<5 % allocated to dentistry in India) face service shortages (Shah, 2004). Social insurance systems (e.g., Germany, France) mitigate inequities through employer-employee contributions but often exclude advanced treatments (e.g., implants) from mandatory coverage (Pegon-Machat et al., 2016; Ziller et al., 2015). The COVID-19 pandemic amplified these preexisting fissures: while Australia temporarily expanded telehealth subsidies, Greece suspended non-emergency public dental services, disproportionately impacting vulnerable groups (Srivastava et al., 2017; Damaskinos et al., 2016). However, longitudinal data on pandemic-era reforms remain sparse (only 21.4 % of included studies addressed 2020–2024), necessitating cautious interpretation (Organization WH, 2022; Proaño et al., 2024). Although some nations have made progress toward integrating oral health into Universal health coverage frameworks - defined here as policies ensuring equitable access to essential health services without financial hardship - most systems remain fragmented and exclusionary, particularly for geriatric and advanced care. The pandemic further exposed systemic weaknesses, with limited adaptive capacity in many settings (Neumann and Quiñonez, 2014; Manski et al., 2014). Our analysis identified three systemic factors perpetuating disparities in dental service coverage show Low-income households—whether insured or uninsured—faced significantly higher odds of catastrophic health expenditures compared to higher-income or fully insured groups (P < 0.01) (Sayuti and Sukeri, 2022). This disparity highlights how even within insured populations, coverage gaps and high out-of-pocket costs persist, particularly in systems with exclusionary benefit designs. For example, in Spain, 97 % of dental spending occurs through out-of-pocket payments (Bravo et al., 2015), reflecting limited financial protection despite formal insurance coverage. Similar patterns are observed in both high- and low- and middle-income countries, especially for adult dental care. Entitlement systems frequently exclude older adults, particularly in insurance-based models. The United States Medicare program's exclusion of routine dental care leaves 70 % of seniors without coverage (Manski et al., 2014), while even universal systems like the United Kingdom National Health Service impose co-pays for non-urgent adult treatments. Low-and-middle-income countries show sharper declines, with only 34 % of studied countries covering geriatric dental services versus 89 % covering pediatric care. Geographic and Racial Disparities of Rural populations and racial minorities face compounded barriers were Provider shortages Indigenous Australians experience 40 % higher rates of untreated decay due to misdistribution of services (Srivastava et al., 2017). United States Medicaid beneficiaries in Southern states have 58 % fewer dental providers per capita than the national average (Taylor et al., 2021) and Nordic countries report 25 % lower dental utilization among immigrant groups despite universal eligibility (Pälvärinne et al., 2018). These inequities stem from policy choices—like tying coverage to employment (Germany) or prioritizing urban clinics (Thailand)—rather than biological need. The consistent underrepresentation of marginalized groups in coverage schemes (e.g., India's exclusion of informal workers) suggests oral health remains a marker of broader social stratification. These findings challenge the notion that Universal health coverage frameworks inherently address oral health as a universal right. While some countries (e.g., Brazil, Thailand) explicitly include dental care in Universal health coverage mandates (Neumann and Quiñonez, 2014; Srimuang and Pholphirul, 2022), most adopt exclusionary models - prioritizing children or limiting benefits to emergency care (e.g., United Kingdom National Health Service adult coverage (Sinclair et al., 2019)). Such fragmentation contradicts World Health Organization's 2021 resolution calling for integrated, prevention-oriented oral health systems (Organization WH, 2022; Eaton et al., 2023). While this study did not directly assess the clinical or systemic linkages between oral health and overall health, the observed disparities in coverage suggest that inequitable access to dental care may exacerbate broader health inequalities.

4.1. Limitations and future directions

This review has three limitations. First, 71 % of data predate 2020, potentially obscuring post-pandemic policy shifts. Second, inconsistent reporting of out-of-pocket costs—often presented as proportions of total expenditure rather than household income—constrained catastrophic health expenditures comparability. Third, variability in service classifications (e.g., “basic” vs. “advanced”) across countries necessitated conservative synthesis. Future research should standardize metrics for expenditure and coverage while tracking pandemic recovery policies.

4.2. Policy recommendations

To advance equitable Universal health coverage integration, three interventions are paramount. First, adopt tiered coverage models that guarantee public financing for preventive and basic care (all ages) while subsidizing advanced treatments for high-need groups. Second, implement out-of-pocket ceilings, emulating Sweden's annual dental cost cap (€300/household). Third, target marginalized populations through Medicaid-style expansions in low-and-middle-income countries (e.g., India's Ayushman Bharat) and inclusive eligibility criteria in high-income countries. Such measures would align dental coverage with the World Health Organization's 2021 oral health resolution, ensuring progress toward Sustainable Development Goals 3.8.

5. Conclusion

This scoping review reveals significant global disparities in dental health coverage, shaped by economic status, health system design, and policy priorities. High-income countries generally provide broader, tax-funded access to basic oral care, while low-and-middle-income countries often restrict services to emergency or public-sector beneficiaries, leaving vulnerable populations underserved. Out-of-pocket costs remain a major barrier worldwide, disproportionately affecting older adults, low-income households, and marginalized communities. Although some nations have made progress toward integrating oral health into Universal health coverage, most systems remain fragmented and exclusionary, particularly for geriatric and advanced care. The pandemic further exposed systemic weaknesses, with limited adaptive capacity in many settings. To advance equitable Universal health coverage, the review underscores the need for tiered public financing models, out-of-pocket expenditure caps, and targeted expansions addressing underserved groups. Aligning these efforts with the World Health Organization's 2021 oral health resolution is essential for achieving Sustainable Development Goals 3.8 and ensuring oral health is recognized as a fundamental component of overall well-being.

Availability of data and materials

Reviewed papers and extracted information are available and could be sent upon reasonable request.

Authorship contributions

The conception and design of the study, or acquisition of data, or analysis and interpretation of data & Final approval of the version to be submitted by M.B.

Drafting the article or revising it critically for important intellectual content by M.S.

CRediT authorship contribution statement

Mohsen Sharif Zadeh Ardakani: Writing – review & editing, Writing – original draft, Validation, Software, Resources, Methodology, Investigation, Formal analysis, Data curation. Mohsen Bayati: Writing – review & editing, Validation, Supervision, Resources, Project administration, Data curation, Conceptualization.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Appendix A. Supplementary data

Supplementary material: Summary of reviewed evidences of oral health coverage in selected countries.

Data availability

Data will be made available on request.