Discussion
The present study showed irregularities between different continents and countries worldwide in terms of dental specialties.
Orthodontics, the first dental specialty to be recognized, was the official dental specialty in every country. Orthodontics was the constant element for every country or pattern of dental specialty. Every country which recognized dental specialties did not fail to include orthodontics. Oral surgery showed a trend similar to that of orthodontics. Other dental specialties that are globally recognized and performed in clinical practice include periodontics (18), pediatric dentistry (16), prosthetics (14), oral/dental maxillo-facial radiology (12), and endodontics (11).
Orthodontics and functional jaw orthopedics showed clear differences in terms of organization of a specific dental specialty worldwide. In majority of countries, the orthodontics specialty merged both, including some parts of orthopedics, although it was not included as an officially recognized specialty. In the USA, both orthodontics and dentofacial orthopedics are included under the same specialty (Orthodontics, the “Orth” specialty). In contrast, the functional jaw orthopedic specialty is a separate officially recognized dental specialty in Brazil, Russia, and Lithuania, including different skills that cannot be classified under the orthodontics specialty.
Dental specialties were listed in the descending order; however, oral surgery and maxillo-facial surgery were grouped together because these two closely related specialties can be analyzed more easily, towing to the fact that some countries recognized both specialties, while others recognized just one of them. Therefore, the maxillo-facial surgery specialty could be classified under Medicine or Dentistry, depending on the country. Countries, such as Canada, Indonesia, South Africa, and the USA, considered oral and maxillo-facial surgery as the same dental specialty, and Brazil also considered oral and maxillo-facial trauma as the same specialty. In contrast, Australia, New Zealand, and a vast majority of European countries officially recognized oral surgery, but not maxillo-facial surgery, as a dental specialty. Finally, Russia officially recognized oral surgery and maxillo-facial surgery as two separate dental specialties. The clear exception is The Netherlands, the only country that recognized maxillo-facial surgery and not oral surgery. Notably, maxillo-facial surgery was commonly recognized in non-European countries (72.7%), while in Europe it was considered as a different dental specialty than oral surgery in Lithuania (5%).
Significant variations were also observed in South Africa, the only country which considered periodontics and oral medicine as the same dental specialty.
Additionally, there were significant geographical variations within a country. For example, Germany recognized orthodontics and oral surgery in a general way throughout the country, but also had a particular organization in smaller territories, such as federal states and cantons. These cantonal differences can result in new dentistry-recognized areas and specialties, such as public health, and the number of officially recognized dental specialties in some areas can reach as high as six.
We considered Ireland a European and not an Anglo-Saxon country, because this study was based on officially recognized dental specialties; therefore, Ireland was clearly affected by the European Union regulations. We considered the legal factors, rather than cultural or geographical factors, more important in contributing to Ireland’s grouping.
Notably, a large number of dental specialties exist worldwide. Among those, 12 exist in Brazil alone; however, the existence of the other 20 dental specialties is still surprisingly high. Although almost every country has its own healthcare system, legislation, and a variety of rules and regulations, some of the most frequently recognized dental specialties were common among the majority of the analyzed countries.
Regarding the patterns of dental specialties, the G index showed total variation for all the analyzed countries (G = 0.424). Therefore, the total global degree of inequality related to the number of dental specialties in the analyzed countries was 42.4%. The G index decreased to 0.404 and 0.216 when only European and non-European countries, respectively, were considered and reached a minimum value (G = 0.027) for Anglo-Saxon countries. Based on these values, the Anglo-Saxon countries had the greatest similarities with respect to dental specialties. However, the number of European countries was significantly higher than that of Anglo-Saxon countries, which may have influenced the final value of the index.
Hierarchical cluster analysis revealed six patterns in dental specialties. A critical analysis indicated that Brazil, because of its absolute singularity, similar to Japan, constituted isolated clusters, and Russia and Lithuania, because of their significant historical, geographical, and political relations, constituted a separate cluster.
The European countries were integrated into four clusters: the first included Lithuania and Russia; the second comprised countries that had not officially recognized dental specialties (Spain and Austria) yet; the third comprised 12 countries, of which 10 recognized between two (Luxembourg, Ireland, Greece, Germany, Cyprus, and Denmark) and three or four dental specialties (Italy, Portugal, France, and the Czech Republic), always including orthodontics and oral surgery; and two recognized two specialties but did not include oral surgery (Belgium and the Netherlands). Finally, the remaining European countries (Switzerland, Romania, Norway, Sweden, and Poland), which had a high number of dental specialties and were located in the eastern part of Europe, were clustered with Anglo-Saxon countries (United Kingdom, Australia, New Zealand, Canada, and the USA), Indonesia, South Africa, and Turkey. The presence of European countries belonging to the European Economic Area in four different clusters suggests that the common legislation (Directives 2005/36/CE and 2013/55/UE) is currently indefinite, and therefore allows for a wide range of variations.
In contrast, all Anglo-Saxon countries were included in the same cluster and are as close as possible to each other. This may be the reason for the lowest G index value for Anglo-Saxon countries in this study. Therefore, the Anglo-Saxon pattern of dental specialties is more consistent than the European one. Anglo-Saxon countries had a higher average number of dental specialties i.e., between 10 and 13, and shared a minimum of 10 specialties i.e., the 10 most frequent specialties found in this study.
Some inequalities might have originated because different countries recognize different dental specialties. Moreover, this study highlights the difficulties in accessing dental specialization, barriers to board certification [
24], restrictions on working abroad to maintain the same dental specialization [
25] and guaranties and a lack of control over the names of specialists among countries. These limitations should be resolved to maintain and equilibrate the quality of work and services for both dental professionals and patients. There should be an agreed list of competencies for each specialty to enhance harmonization and standardization [
7]. A common pattern of dental specialties would make it easier to work abroad while maintaining the same specialization.
In specialization training, time is an important factor and one of the most common reasons for refusal of nostrification/recognition within the EU. The 2005/36/EC and 2013/55/EU directives set that full-time specialist dental courses shall be of a minimum of three years’ duration. So, the most common duration in Europe is just three years (Austria, Bulgaria, Croatia, Cyprus, Estonia, Finland, France, Greece, Hungary, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Poland, Portugal, Romania, Slovakia, Slovenia, Sweden), with some countries asking for another mandatory, previous year of general dentistry, as Germany or Switzerland, and Denmark asking for at least two years as a dentist,—and one of the two years must be with children—before you can apply for the orthodontic specialist program. In Belgium there is a sixth year, in addition to the five-year degree in dentistry and in order to access the profession as a general dentist and to further gain the required title of specialist in general dentistry. In Belgium the specialization programs in periodontics and orthodontics, last three years and four years respectively. The orthodontic specialization program tends to switch to a 4-year program, as currently happens in the Netherlands, Switzerland and Czech Rep.
The control and method of allocating places for specialization training is really different between countries, even between EU members, because European directives allow very different options so that specialized theoretical and practical dental training can be carried out “in a university center, in a treatment teaching and research center or, where appropriate, in a health establishment approved for that purpose by the competent authorities or bodies”. So, the involved institutions are multiple.
Consequently, in some countries this control is under the responsibility of the Universities. So, in Italy the number of seats is the responsibility of the department of the university concerned, which creates a "Scuola di specializzacione" as part of the postgraduate program within the university.
On the other hand, in many other countries this control is more central and related to Health Ministry. So, in Poland, places are allocated centrally, directly through the Ministry of Health, which accredits universities and private practices for this purpose and the entire training ends with a state exam. In a similar way, in France, the Regional Board of Health (ARS) reports the needs of each region, and it is the Ministry that decides upon the schools (currently 14) and seats (approximately 50–55 every year), having to finish, by also presenting a final exam.
Austria has a mixed model, where the number and allocation of dental specialists is surveyed by the Health Ministry too, but the Universities have the possibility to offer as many education seats as they decide and this is more or less an economic decision of each university, because the educational costs for specialization studies are not covered by the government. In Belgium, the Health Public Ministry set the schools (currently five in orthodontics) and number of dental specialists to be trained (approximately 13 every year in orthodontics), but the Faculties choose their candidates.
Only in some countries is the control more related to the regulatory body of the dentists. So, in Portugal, the Ordem dos Medicos Dentistas (OMD) recognizes the suitability of postgraduate degrees in orthodontics (180 ECTS, full-time training), five at the moment, three in public Faculties and two in private ones and it is the College of Orthodontics, made up exclusively of orthodontists trained in suitable departments, who proposes to the OMD how many orthodontists it can train, although not all of them take the national final exam.
The titles of master in orthodontics and orthodontic specialist, function alongside each other in Italy and some Scandinavian countries. What makes a master's degree different from the title of specialist is the lack of official recognition as a specialist in that country, a term that is usually restricted only to those with an official training. Certain traits such as a three-year full-time training are mandatory and easy to identify but that is not enough. The European directives additionally establish the need to be supervised by competent authorities or bodies. This is particularly problematic in countries like Spain, without inner regulation of dental specialties or Austria with a very recent regulation (approved in Feb 2023, operative since September 1st, 2023) which makes the automatic recognition of the title impossible in other countries and creates confusion to patients, who cannot discern who is a properly trained dentist as a specialist, because there is not an official list of specialists. Currently, most countries have public online information with up-to-date lists of specialists, but patients usually do not verify the official doctor´s credentials, due to a lack of knowledge.
Another clear trait of the quality of the training of a dentist as a specialist is the recognition by some other institutions that establish common programs, rules and parameters (number of students, student/teacher ratio, director qualifications, number of treated cases, facilities, end of specialization thesis, evaluation criteria, evaluating commission, etc.) to standardize specialty training in Europe. The most important one in orthodontics is NEBEOP (Network of Erasmus Based European Orthodontic Postgraduate Programs) and EFP (European Federation of Periodontology) in periodontics. Their standardization follows the European legislation and expand, in a very detailed way, the criteria to be fulfilled (i.e., 4800 h of training for orthodontists), but it is not mandatory for the practitioner to obey these criteria during their training specialty. Recently, the World Federation of Orthodontics (WFO) has updated the minimum orthodontic program requirements with guidelines to be used worldwide [
26].
The European directives on the recognition of professional qualifications (2005/36/EC and 2013/55/EU) do not recognize any restriction of professional practice to general dentists. Only national regulations could set that type of limitation and it would have an exceptional character.
The availability to make a master's degree affects not only the quality of education and research as has been reported [
8], but the stability of the dental market and the number of people in a particular specialty. The chosen institutions (Universities, Health Ministry, official colleges and councils, etc.) to control the dental specialization procedure could be a major determinant, and the important differences in the total numbers of general dentists and specialists and ratios to existing population between different countries, has to be highlighted. In our opinion the role of the scientific societies of specialists is currently underestimated and only in a few countries do they play a significant role. For example, in the Czech Republic two committees, one for accreditation of the specialization and the other one for education in dentistry, act as advisory bodies to the Ministry of Health, which governs the procedure. Both of them have nine members, two nominated by the Czech Dental Chamber, two by the Czech Orthodontic Society, two by the Universities and three by the Ministry of Health.
It is important to highlight that the published information related to dental specialties differs significantly between the 31 analyzed countries, depending on the way official documents or annual reports are published, the purpose of the main webpage related to dental institutions, the health system organization, or just the visual aspect of delivering public information. Additionally, there are significant variations in the content and names of several dental specialties in different countries, which make comparisons difficult.