A review on oral health care oral health outcomes of four different health care systems

Background : A universal approach to oral health is said to improve oral health outcomes and lessen inequity, but research has shown mixed results. This study aimed at critically reviewing the oral health care systems of four countries in terms of structure, scope, and delivery, along with their impact on oral health outcomes. Methods : A comparative literature review of the oral health care systems in Brazil, New Zealand, Canada, and Sweden was performed between August 2017 and January 2018 using PubMed/MEDLINE and the key words ‘universal’ AND ‘dental OR oral’ AND ‘care OR access’ AND ‘outcome’. This is a critical essay based on evidence available in the literature and interactive conversations with 12 key informants from these countries. Results : All four countries provide some form of universal health care, but the administration, funding, and delivery of oral health care varied. Approximately 6% of oral health care expenditure in Canada is publicly funded. Brazil provides full publicly-funded oral health care at the point of use via salaried dental professionals, while Sweden offers a high-cost protection plan favouring those with greater needs, and New Zealand delivers publicly-funded oral health care to children–up to their eighteenth birthday. With service utilization varying, 61% of Canadian children, 67% of Swedish children, 50% of Brazilian children, and 45% of New Zealand children are caries-free at age 12, while 6.4%, 0.8%, 6.5%, and 9.6% of adults between the ages of 20 and 79 years are edentulous, respectively. Conclusions : All countries have some form of publicly-funded oral health care, but vary in the way that the services are delivered, from salary-based providers to private-practice models. Service utilization and oral health outcomes differ in each country.

Oral health has a significant impact on overall health and quality of life, and yet it remains neglected and overlooked in most health care systems (1). Social disparities in access to oral health services are found almost everywhere, but they are more prominent in countries where oral health care is administered, funded, and delivered predominantly through the private sector (2). Volunteer and charity-based dental clinics have not demonstrated lasting effects on improving a population's oral health because they mostly provide relief of pain and emergency care (2). The existence of charitable dental clinics in wealthy countries might be indirectly demonstrating the failure of the dental profession, the government, and society to address the oral health care needs of all citizens (3); charitable dentistry is not a substitute approach for equitable access to care. Those bearing the greatest burden of dental disease tend to be members of socially and economically deprived segments of the population that are least likely to be able to afford oral health care (4).
Arguably, a publicly-funded or "universal" approach to oral health would eliminate or reduce the impact of affordability as a barrier; it is also believed to improve oral health outcomes and lessen inequity. This manuscript employs the term universal oral health care to refer to the type of care that is universally-funded by the federal government or a central agency (either by tax payers or by subsidized care provided by an "insurer") and is available to all people regardless of their ability to pay. However, research on the impact of universally-funded oral health care on access to treatment and on oral health remains sparse and indicates mixed results (5,6). This study critically explores the extent to which different oral health care systems impact three selected oral health outcomes, including service utilization (i.e., visiting a dentist in the previous 12 months), dental caries experience via Decayed-Missing-Filled-Teeth (DMFT) in 12-year-olds, and edentulism (i.e., being toothless) in adults between the ages of 20 and 79.
Given that publicly-funded or universal oral health care likely exists within an equally publicly-funded or universal health care system, a comparative review amongst Canada, New Zealand, Brazil, and Sweden is presented and discussed in terms of their oral health care systems' structure, scope, and service delivery, as well as their impact on the oral health of their populations. These four countries were selected because they all offer a financially subsidized health care system to offset the cost of some, or all, health care needs of their respective populations; they are geographically placed in different areas of the globe (e.g., two are in the Northern and two are in the Southern hemispheres; two are located in the Americas while one is in Europe and the other is in Australasia) and they offer four different ways to fund and deliver oral health care. This study recognises the similarities and differences between the counties studied, while acknowledging the influence of an array of factors upon care utilization, including age, gender, educational level, and perceived need for and benefit from care, that were not assessed in this current manuscript.

Methods
A comparative review based on the available literature and on interactive conversations with 12 key informants from the following four national oral health care systems was undertaken: 1) The Brazilian Unified Health System; 2) The New Zealand Dental Care System; 3) The Swedish Dental Care Benefits Scheme; and 4) The Canadian Public Health Care System.
A brief search on PubMed/Medline using the key words 'universal' AND 'dental OR oral' AND 'care OR access' AND 'outcome' (limited to Brazil, Canada, New Zealand, and Sweden) was performed between August 2017 and January 2018. Inclusion criteria aimed at identifying any publication (peer reviewed manuscripts, conference procedures, reports, and reviews) pertaining to those four countries that contained the selected key words, e.g. publications that dealt with the chosen oral health outcomes in light of their respective oral health care systems. No limits on the year of publication were imposed in order to retrieve historical information pertaining to the establishment of the health and oral care system in those respective countries. The search was supplemented by specific information requested from key informants in each country.
The twelve key informants were academics (n = 3), administrators/managers of oral health care programs (n = 3), and oral health care professionals (n = 6) identified as those with first-hand experience about their respective health care systems and could offer a unique take on the following question: "what would be a positive and a negative aspect of your oral health care delivery system?" This question aimed at revealing more information and details about the respective systems beyond the published literature, providing an insider view. Given the nature of this question, it may have introduced personal biases rather than verifiable accounts. Unlike a qualitative study, answers to this question were not analyzed thematically for their content; rather they were used to illustrate the experiences of those working within the four different oral health care systems. Hence, the answers to the above question were by no means exhaustive or generalizable. Key informants were approached between September 2016 and August 2017 and were asked to also identify any supporting grey literature that would not likely surface during our literature search. When applicable, quotes from these informal face-toface and electronic interactions with key informants were used to support or refute our line of reasoning.
The search strategy described above yielded 882 documents, after 36 duplicates were excluded, and were limited to journal articles, commentaries, reviews, and systematic reviews as indexed at the search engines used. Publications that were about animal studies and in languages other than English, Portuguese, Italian, Spanish, and Swedish (which the authors could understand) were eliminated, yielding a subtotal of 697. We

Results
Health care systems: scope and structure All four countries offer some form of universally-funded health care to their citizens, with Brazil, Canada, New Zealand, and Sweden spending 8.3%, 10.4%, 11.0%, and 11.9% of their Gross Domestic Product (GDP) on health care, respectively (7) ( Table 1).
Canada: Publicly-funded health care is financed with general revenue raised through federal, provincial, and territorial taxation. The provinces and territories administer and deliver most of Canada's health care services under a private model within the Canada Health Act, without direct charges to the patient. All health care services must adhere to the five principles of the Canada Health Act: 1) publicly administered; 2) comprehensive in financial coverage of care; 3) universally available to all Canadians; 4) portable across provinces; 5) and accessible (i.e., without user fees) (8).
Brazil: The Unified Health System ("Sistema Único de Saúde"-SUS) oversees the payment and delivery of health services publicly provided at federal, state, and municipal levels with complementary participation of the private sector; this public-private mix led to less than half of health spending actually being funded by public sources alone (6,9,10). The SUS works under the three basic principles of universality, equity, and comprehensiveness informed by decentralization, regionalization, and social control (10).
New Zealand: The public health care system is government-funded; it is a complex net of various agencies at different levels and includes the Ministry of Health, the Pharmaceutical Management Agency, and the Health Quality and Safety Commission.
Although there are no deductibles, co-payments are required for general medical practitioner's services. New Zealanders residing in low-income areas have their annual per-patient capitation paid for medical care and, in return, patient co-payments are capped (11).
Sweden: All three levels of Swedish government-national, regional, and local-are involved in the health care system. Much like Canada and Brazil, there are no direct charges to the patient for treatment. The principles of health care in Sweden mandate the system to offer equal entitlement to dignity and the same rights regardless of individual status in the community, to give priority to those in greatest need of care, and to be cost effective in all its levels (12). Public funding and delivery of oral health care exists to varying degrees in all four countries. In Canada, the provision of these services has been excluded from the Canada Health Act, with the exception of the federal government's responsibility to provide oral health care to Indigenous people, serving members of the Canadian Forces, eligible veterans, inmates in federal penitentiaries, and some groups of refugee claimants (13).
Most provinces also provide limited public dental care benefits for those living in financially strained circumstances. Approximately 6% of Canadian annual dental expenditure comes from public funds, but the care is primarily delivered by private practitioners on a fee-for-service model.
Brazil offers the SUS, a public oral health care system that is universal and employs salaried dental professionals working in community clinics (usually referred to as Family Health Units) within primary health care services (14,15). Oral health care is delivered through a network of dentists and dental assistants and, in some cases, dental hygienists.
When specialized care, including periodontal or endodontic treatment, is required, patients are referred to a specialized dental centre (CEO) for free care, administered by salaried dental professionals (15).
New Zealand offers free oral health care to children up the age of 18, delivered by either oral health therapists or dentists. Adults pay for care privately, in the form of out-ofpocket payments direct to the private provider. Treatment for no-fault dental trauma is provided by private dental practitioners and is funded at a fixed cost by the Accident Compensation Corporation, which also covers temporary visitors who have suffered personal injuries (16).
In Sweden, basic oral health care is paid for children and adolescents, while it is subsidised to those older than 21 years of age under a high-cost protection plan. Under this plan, patients receive a small fixed annual subsidy for examinations and preventive care, typically around $34 USD for adults between 21 to 29 years of age and those older than 65, and $17 USD for 30-to 64-year-olds (as per the exchange rate on October 10, 2017 at USD $1 for SEK8.09). For other oral health care services within a 12-month period, patients older than 21 years of age pay the full cost of services up to $371 USD (SEK3000), 50% of the cost for services between $371 USD and $1,854 USD (SEK15,000), and 15% of costs for services above $1,854 USD. There is no cap on users' charges for oral health care, as the system is based on needs rather than on affordability-where those with greater care needs pay only part of the treatment cost (18).

The workforce
The available dental workforce likely influences access to dental care. In 2017, Brazilhad 232 dental schools, Canada had 10, New Zealandhad one, and Swedenhad four; the dentist to population ratio in these countries also varies (Table 1). Despite the number of newly graduated dental professionals in these four countries, very few may want to pursue careers in dental public health in Canada (19); while in Brazil, the public oral health care system employs the largest number of salaried dental professionals (14,15). Either way, the subsequent lack of strong leadership in public health has resulted in deteriorating support for oral health professionals who typically provide care for marginalized populations. For example, the Canadian National School of Dental Therapy was closed in November 2011 (20), even though Canada has historically relied heavily upon dental therapists to provide community-based care in Indigenous communities. Only New Zealand (21), and now Canada to a much lesser extent, continuously employs oral health therapists (a.k.a. dental nurses or dental therapists) as part of the dental workforce aimed to improve access to oral health care for children and adolescents (22). In Brazil, the development of the National Policy of Oral Health in 2004 placed access to oral health care within the national agenda (23), while dental hygienists experienced increased limitation in their scope of practice over the past 30 years. Interestingly, the scope of practice of dental hygienists in Canada and Sweden (16) is gradually expanding and those who can already practice independently can also provide interim stabilization and atraumatic restorative therapies. Regardless of the type of dental professional, workforce alone is likely insufficient to promote positive oral health outcomes and equitable access to oral health care.

Oral health outcomes
In the four countries studied, the percentage of the population utilizing oral health care services for any reason in a 12-month period varied, ranging from 44.4% in Brazil (24), 64.6% in Canada (25), 51.2% in New Zealand (26), to 87.4% in Sweden (27). The percentage of caries-free 12-year-old children was: 50% in Brazil; 61% in Canada; 45% in New Zealand; and 67% in Sweden. The percentage of edentulous adults between the ages of 20 and 79 in each country was: 6.4% in Canada, 9.6% in New Zealand, 0.8% in Sweden, and 6.5% in Brazil (Table 1). Despite the overall decrease in the incidence of dental decay in developed countries, profound oral health disparities may still exist based on gender, income, age, and race/ethnicity and are beyond the scope of this manuscript (28,30,31).

Key informants' interviews
The answers gathered from 12 key informants are summarised in point form in Table 2, while some of the full quotations are presented in the discussion-when needed to support the claims made. As they were prompted to reflect on at least one positive and one negative point pertaining to their respective oral health care systems, the answers were evened out; we eliminated repetitive points mentioned by different individuals. Although anonymity was guarantee for their participation, some information is provided in terms of area of work (e.g., academia, private practise, etc.), age, and the number of years working in that capacity.

Discussion
This manuscript critically reviewed the oral health care systems of four different countries in terms of their structure, scope, and impact on oral health. Access to oral health care remains a major key in reducing the burden of oral diseases and improving the quality of life to the extent that "universal dental care is the only way to erase the [oral health] disparities" (29). However, there is limited documentation as to what extent publiclyfunded (i.e., universal) oral health care can lead to acceptable oral health outcomes and can eradicate oral health inequalities effectively (2). In the current study, utilization of services did not seem to depend on the actual availability of oral health care, for example, when comparing utilization rates in Brazil (44.4%) and Sweden (87.4%). Utilization does depend on many other factors other than availability, number of providers, or universality, including predisposing and enabling factors such as distribution and geographic location of the services, relevance of the services offered, and patients' preferences for providers they trust (30,31). Utilization of oral health care services also depends on health care policies, oral health behaviours, and self-perceived oral health status (3,5,23).
Whether or not oral health care is universally offered, Saekel emphasizes that oral health can only be achieved "if dentists take a less interventionist approach … as treating dental diseases [and focus on] preventive and tooth-preserving methods" (32). When asked about a positive aspect of the Brazilian public dental care system, a 32-year-old salaried dentist working at a CEO in Porto Alegre for 4 years mentioned this less interventionist way of treating patients:

"What I like about the CEO is that we receive the referral for a particular treatment so we know what we will be doing…we do not go beyond what was suggested by the other colleague just because the patient gets it all covered. We do what the patient needs and avoid doing what is not [needed]."
In Canada, where oral health care continues to be privately financed, administered, and delivered, one-third of Canadians remain without any form of dental coverage, while 64.6% of the population utilizes the services. Moreover, less than 6% of Canadians receive some form of universal coverage via government-sponsored dental plans (33). According to a 36-year-old junior faculty member from the Faculty of Dentistry in Western part of Canada, a potentially negative aspect of Canadian dental care is this discretionary aspect For families living at, or below, the poverty line, out-of-pocket dental expenses are potentially catastrophic health expenditures. Disposable income is virtually non-existent in these households and so oral health inequalities remain (34). Hence, low-income Canadians may rely on the availability of charitable or community dental clinics to have their needs addressed (2) or end up in hospital emergency rooms for dental pain relief (35). However, the availability of universal or subsidized oral health care does not imply that all individuals will obtain necessary treatment-given that other life priorities come into play, along with issues of dental fear and anxiety (36) and the array of other factors described above (30,31). Although Sweden pays for oral health care for children and adolescents, and subsidizes it for adults, a 45-year-old salaried dentist working for seven years at a dental clinic for low income Swedes told us that: "If you look as an outsider, the Swedish dental system is almost perfect; you have free dental exams and the more you need in treatment, the less you pay yourself. But every patient here is different and some do not care if they can have that tooth fixed. They have other burning issues in life, survival is one of them, and in that case, a missing or a broken tooth does not get too much of their attention." Ismail and Sohn (37) further highlighted that having access to universally-financed oral health care does not fully eliminate disparities, at least in the caries experiences of 6-and 7-year-old children in Nova Scotia, Canada, for example. In fact, in New Zealand, early childhood caries reduction has stagnated-despite free access to dental care for that age group. Such stagnation in caries reduction points to extraneous factors, including poverty, social inequality, and sugar consumption, as strong players in dental caries development (38).
These observations are not just limited to children, studies involving older adults who receive medical and oral health care at a discounted cost still show a social gradient in utilization against the poor and the very old (39). With a large number of older adults keeping their natural teeth for life, a 52-year-old private practicing dentist (for 18 years) from Vancouver commented on the need for constant adaptation of the health care system: The robust Brazilian public oral health care system seems to be utilized more by those who are socio-economically disadvantaged and have a greater need for treatment, although it experiences less than 50% of overall use. Oral health inequalities remain strong within rural and remote communities; nationally, primary dental care coverage is still below 40% for Brazilians (40). Public oral health systems have yet to show their intended role in promoting positive oral health outcomes, reducing inequalities, and providing universal access to comprehensive oral care regardless of the number of dental professionals available. According to a 47-year-old Brazilian salaried manager working at a large public dental clinic for 21 years: Swedish universal oral health care seems to be more equitable in reducing social inequalities, as only about 7.7% of adults between the ages of 20 and 79 refrained from dental treatment for financial reasons in 2016 (41), while more than 80% of Swedes visited a dentist in a 1-year period (27,42). Interestingly, the attendance rate of Canadians (who do not benefit from universal oral health care) is almost 70%; however, many more Canadians (approximately 17%) do not get dental treatment due to financial reasons (32). Could this discrepancy between Canada and Sweden be a result of the system's failure to look after its citizens? Such accountability of a nation to its citizens was indeed an issue for a 26-year-old salaried oral health therapist in New Zealand's North Island who had been working for 5 years: "I sometimes see myself running in circles. I see a young kid, usually from a low income family, with lots of dental disease and the parents want all done at once, under general anaesthesia at a hospital, which I refer. When I see this kid again with a more permanent dentition, the disease is still there, and there are no baby teeth left. Is our entire system that good that [it] may cover an expensive treatment at a hospital, and yet, fail to prevent the disease to happen again?" Universal oral health care should be understood within a complex systems model, as suggested by Rutter and colleagues (43), in which "poor health and health inequalities are outcomes of a complex multitude of interdependent elements within a connected whole".
These elements include patients' attitudes toward dentistry, living circumstances, selfperceived oral health, and dental fear and anxiety (35,44). Such complexity also precludes any direct causal link between universally-funded oral health care and reduced oral health disparities. For example, even though Brazil provides universal public oral health services while Canada does not provide dental coverage for most adult citizens, oral service utilization in Canada (64.6%) is higher than that of Brazil (44.4%) according to the available literature.
Although at differing levels, oral health disparities in Canada, Sweden, New Zealand, and Brazil will probably not change without widespread commitment from government, dental professionals, stakeholders, and society at large. However, together with this combined commitment, Werhane (45) pointed out that "morally … a systemic approach has to take into account the multi-perspective dynamics involved in health care … without ignoring the critical roles and responsibilities each of professionals, providers, payers, or patients",, which is a similar suggestion as that brought up recently by Rutter et al. (42).
Although such systems thinking has yet to materialize in dentistry, "oral health care should never be a choice between feeding your children and getting that front tooth fixed," said a 52 year-old Canadian private dentist from Vancouver.
It is undeniable that both the Swedish high cost-protection scheme and Brazilian publiclyfunded oral health care tend to minimize or even eliminate affordability as a barrier. However, neither system has yet to fully eliminate inequity nor oral health disparitiesutilization rather than access remains a personal choice mediated by life circumstances, choices, and perceived benefits. Moreover, Leake (3) highlights that "unless an alternative direction is taken, dentistry will lose its relevance as a profession working for the public good and this will be followed by further erosion of public support for dental education and research" regardless of undergraduate dental education's attempt to address dental public health (19), community services (46,47), and social responsibility (48) within its future workforce.
Sweden and Brazil are not the only countries to have adopted a more universal oral health care system (48). Austria, Denmark, Germany, Poland, Thailand, Spain, and Mexico provide basic oral health care services-either through government-sponsored or employment-based insurance-while the same care is delivered through a combination of subsidized private practitioners and government health services in Greece, Turkey, and Finland (49). Cuba, Chile, Colombia, Costa Rica, and other Latin-American countries offer free primary and specialized oral health care, mainly to children and mostly limited to school programs (50). However, there is an urgent need to evaluate the various oral health services through country-specific health care systems in terms of their ability to promote oral health outcomes and address oral health disparities regardless of age, gender, socioeconomic status, or health conditions (2,33). This study does not distinguish health care from oral health care: the mouth is part of the body and should be equally cared for. However, it is known that oral health care utilization is mediated differently from general health care utilization (51,52,53).
The limitations of this critical review include a lack of comparisons with countries that have no publicly-funded health care system and the use of convenient, informal limited number of interviews, without a proper methodology, to collect and analyze information from key informants even though they offered a first-hand account for an insider view of their respective oral health care systems. Furthermore, the use of DMFT and edentulism as outcome measures of oral health pose another limitation on this review given their inherit epidemiological disadvantages. This study did not gather data on the many other factors that are known to influence service utilization including age, gender, educational level, and so on. The countries' historical, political, social, and economic trajectories, which have greatly affected their oral health care systems were also not discussed. Lastly, the lack of a more uniform source of data to support the various statements made throughout this manuscript might have biased the information presented.

Conclusions
Despite having publicly-funded health care-albeit at differing levels-Brazil, Canada, New Zealand, and Sweden struggle to balance utilization and equitable provision of oral health care to all residents. Universal funding of oral health care helps reduce economic barriers in assessing services, but much like universal health care, it does not eliminate disease.
This critical and comparative review provides relevant information to academics, front-line workers, and policymakers by depicting various approaches used to finance, organize, and deliver oral health care services. e There is variation in terms of definition and scope of practice of these professions. In Canada, while dental hygienists perform scaling and root planing and can work independently in some jurisdictions, in Brazil they cannot work independently. An oral health therapists in New Zealand is able to provide restorative and preventive care for children and adolescents until the age of 18, and preventive care (including scaling) for those aged 18 or over.  Figure 1 Searching strategy for the 79 selected publications