Current Teaching of Endodontics in Dental Schools Around the World: A Systematic Review

1. Introduction

Undergraduate university training in Endodontics is essential for students graduating from dental schools to adequately develop their profession as dentists. Dental graduates must acquire the knowledge and skills necessary to perform endodontic procedures with an adequate level of competence (Baaij et al., 2024; De Moor et al., 2013; Segura-Egea et al., 2021).

In recent decades, Endodontics has incorporated new materials and equipment, as well as technical innovations, which increasingly facilitate endodontic treatment, and contribute to better care for patients with pulpal-periapical pathology (Jiménez-Sánchez et al., 2021). In addition, in the last years there have been important changes in the diagnostic and therapeutic criteria for pulpal and periapical pathology (Duncan et al., 2019; Duncan et al., 2023; Galler et al., 2016; Jiménez-Martín et al., 2024; Segura-Egea et al., 2018). For this reason, universities have had to make a significant effort to incorporate all these changes and innovations into both theoretical and practical teaching programs (Al Raisi et al., 2019; Segura-Egea et al., 2021). However, as ESE points out in Undergraduate Curriculum Guidelines for Endodontology, it is still the 'craftsmanship' that gets the job done, highlighting the need for both knowledge and skills training in undergraduate education (Baaij et al., 2024).

Since 1992, the ESE has published curricular guidelines for the undergraduate teaching of endodontics that have served as a reference and guide for dental schools. The latest update of the ESE Undergraduate Curriculum Guidelines for Endodontology has just been published this year (Baaij et al., 2024). However, resources for delivering the endodontic curriculum vary from country to country, and even from school to school within a country (Al Raisi et al., 2019; Segura-Egea et al., 2021), so students may graduate with different levels of knowledge and experience (European Society of Endodontology, 2018).

Knowing how Endodontics is currently being taught in undergraduate dentistry studies is of great interest to determine whether new teaching methodologies, new materials and contemporary techniques, as well as new diagnostic and therapeutic criteria are being incorporated in the teaching of dental students. Therefore, the aim of this study was to analyze current undergraduate endodontic teaching worldwide.

2. Materials and Methods

This systematic review complies with the guidelines outlined by the Preferred Re-porting Items for Systematic Reviews and Meta-Analyses (PRISMA) (Page et al., 2021).

2.1. Review Question

The primary research question was as follows: What are the key components of undergraduate endodontic curricula across different dental schools worldwide? This general question was subdivided into five sub-questions: 1) What are the key characteristics of endodontic education in dental curricula worldwide?; 2) What teaching methodologies are most commonly used to instruct undergraduate dental students in endodontics?; 3) What root canal treatment protocols are taught to undergraduate dental students worldwide?; 4) How are contemporary materials and technologies incorporated into undergraduate endodontic training?; and 5) What assessment methods are commonly used to evaluate undergraduate students' competency in endodontics?.

2.2. Eligibility Criteria

Considering that the aim of the review was to analyse the current teaching of Endodontics, the inclusion criteria established were: 1) studies published in the last 10 years, 2) studies in which those responsible for teaching Endodontics reported some data about the undergraduate training of Endodontics, 3) studies in dental schools around the world. The period of ten years was decided considering that, in the last decade, there have been very important changes in the teaching of dentistry, as well as the incorporation of numerous new technologies into the practice of Endodontics (Al Raisi et al., 2019; Segura-Egea et al., 2021; Baaij et al., 2024). Additionally, the main objective of this systematic review was to analyze the current undergraduate endodontic teaching.

The exclusion criteria were as follows: 1) studies published more than 10 years ago; 2) studies in which the information is not provided by those responsible for undergraduate endodontic teaching, and 3) studies in which the data comes from student surveys.

Reviews, conference articles, letters to the editor and studies based on surveys to students or expert opinions were excluded. No language restriction was applied. Three reviewers analyzed all titles and abstracts, and in some cases the full text, of the articles found, independently and in duplicate. Articles that did not meet the inclusion criteria were excluded. In case of disagreement between reviewers, it was resolved through debate.

2.3. Search Strategy and Information Sources

A literature survey was conducted to identify articles about undergraduate endodontic teaching. The search was carried out in PubMed, SCOPUS and EMBASE, using the following combinations of keywords: (endodontic OR Endodontics OR endodontology) AND (teaching OR training OR education OR curriculum) AND (undergraduate OR pre-graduate) AND (evaluation OR assessment) AND (dental schools OR dental faculty).

Two independent reviewers (J.J.S.-E. and O.A.-E.) conducted the literature search and screened articles for eligibility. Initially, the titles and abstracts were reviewed to assess their relevance to the review. Subsequently, a thorough analysis of the full texts was carried out, evaluating them based on the pre-established inclusion and exclusion criteria. In the event of any discrepancies between the reviewers, these were resolved through direct discussion or, when necessary, by consulting a third reviewer (J.M.-G.), in order to ensure consistency and accuracy in the article selection process.

2.4. Data Extraction

One of the authors (J.J.S-E.) was responsible for data extraction, while four other reviewers (J.M-G.; D.C-B, M.L-L. and O.A-E.) checked the tabulated data to ensure the absence of errors; articles in disagreement were discussed. For each study the following data were extracted: authors and year of publication, country, number of dental schools that responded to the survey, and percentage of dental schools that responded to the survey. In addition, all possible data were collected regarding 1) General characteristics of teaching Endodontics in the dental curriculum, 2) Teach-ing methodology in endodontic training, 3) Root canal treatment protocol used in un-dergraduate endodontic teaching, 4) Use of contemporary materials and technologies in endodontic training, and 5) Assessment methodology in endodontic training.

3. Results and Discussion

A total of 176 records were initially identified, but 14 were duplicates (Fig. 1). One hundred and sixty-two studies were screened for abstract evaluation, and 135 were excluded for not meeting the inclusion criteria. In the remaining 27 articles, the full text was analyzed, discarding 9 articles published more than 10 years ago (Arbab-Chirani & Vulcain, 2004; Cruz et al., 2000; Gatley & Davies, 2009; Murray & Chandler, 2014; Petersson et al., 2002; Qualtrough & Dummer, 1997; Qualtrough et al., 1999; Sonntag et al., 2008; Tanalp et al., 2012). Three other studies were excluded because they were surveys of undergraduate students (Alim-Uysal et al., 2021; Barakat et al., 2021; Braga et al., 2021). One study was excluded because the survey had been conducted among directors of postgraduate programs in Endodontics (Rabiee et al., 2018).

Figure 1. Flowchart of the search strategy following the PRISMA 2020 guidelines for systematic reviews.

Figure 1. Flowchart of the search strategy following the PRISMA 2020 guidelines for systematic reviews.

Finally, 14 articles (Table 1) in which the responsible for teaching Endodontics in dental schools responded to surveys, reporting data on undergraduate training of Endodontics, were selected and included in the review: five studies evaluated undergraduate endodontic teaching in Asian countries (Algahtani et al., 2022, 2023; Alobaid et al., 2022; Baharin & Omar, 2021; Narayanaraopeta & Al Shwaimi, 2015), five other studies analyzed the teaching of Endodontics in European countries (Al Raisi et al., 2019; Brown et al., 2020; Mergoni et., 2022; Sacha et al., 2021; Segura-Egea et al., 2021), three studies investigated different aspects of undergraduate endodontic training in Brazil (Coelho & Rios, 2023; da Costa Ferreira et al., 2021; Rech et al., 2022), and one study analyzed endodontic teaching in Canada (Goyal et al., 2024).

The number of dental schools included in each study varied between six (Narayanaraopeta & Al Shwaimi, 2015) and 41 (Rech et al., 2022). The percentage of respondents also varied greatly, from 20% (Rech et al., 2022) to 100% (Narayanaraopeta & Al Shwaimi, 2015). Taking into account that the response rate was higher than 69% in 11 studies (79%), it can be considered that the data provided are representative of the state of endodontic teaching in their respective countries.

Since the aspects of endodontic teaching assessed in the different studies were different and varied, the data provided by the included studies were extracted and organized into five sections: 1) General characteristics of teaching Endodontics in the dental curriculum, 2) Teaching methodology in endodontic training, 3) Root canal treatment protocol used in undergraduate endodontic teaching, 4) Use of contemporary materials and technologies in endodontic training, and 5) Assessment methodology in endodontic training.

3.1. General Characteristics of Teaching Endodontics in the Dental Curriculum

Ten studies (Table 2) provided data on the year in which endodontics was taught, the status of the supervising endodontic staff, and the staff: student ratio (Al Raisi et al., 2019; Algahtani et al., 2023; Alobaid et al., 2022; Baharin & Omar, 2021; Brown et al., 2020; Goyal et al., 2024; Mergoni et al., 2022; Narayanaraopeta & Al Shwaimi, 2015; Sacha et al., 2021; Segura-Egea et al., 2021). In most dental schools, Endodontics is taught in the third, fourth and fifth years of the curriculum. Theoretical teaching and preclinical practices are taught in the third and fourth years, while endodontic clinical practice is taught in the fourth, fifth and sixth years. The fourth year of the degree in dentistry is the one in which endodontic contents are most frequently taught.

In all dental schools, at least 50% of endodontics teachers are specialists. A major factor in the quality of teaching a subject lies in the level of training of the teachers and their motivation and interest (Ahlberg, 1991). Therefore, training in endodontics must be supervised by teachers with specific preparation and clinical practice in endodontics (De Moor et al., 2013). The situation shown by the surveys included in this review appears to have improved substantially since the study published in 1997 in UK (Qualtrough & Dummer, 1997) when none of the schools had supervising staff with advanced training in endodontics.

The staff: student ratio varies greatly depending on whether it is preclinical or clinical practice, being around 1:5 to 1:15 in preclinical practice (Goyal et al., 2024; Sacha et al., 2021) and 1:3 to 1:8 in clinical practice (Baharin & Omar, 2021; Goyal et al., 2024). These staff: student ratio are similar to those in prosthetics laboratory practices in Malaysian dental schools (1:12) (Daood et al., 2022) and in clinical practice of oral surgery (1:4) in British universities (Dargue et al., 2021). The great variability of the staff: student ratio corresponds to the variable number of students in the different dental schools. Dental schools with large student number tend to have a lower staff: student ratio.

3.2. Teaching Methodology in Endodontic Training

Nine studies provided data on teaching methodology (Al Raisi et al., 2019; Algahtani et al., 2022; Alobaid et al., 2022; Baharin & Omar, 2021; Goyal et al., 2024; Mergoni et al., 2022; Narayanaraopeta & Al Shwaimi, 2015; Sacha et al., 2021; Segura-Egea et al., 2021). Lectures, pre-clinical practices and clinical practices were used by almost 100% of dental schools (Table 3). Problem-based learning and seminars were used in more than 50% of schools. Seminars, video and E-learning are also widely used in teaching endodontics. These results differ substantially from those shown by the study carried out almost 30 years ago in the United Kingdom (Qualtrough & Dummer, 1997), who only identified lectures and seminars as methods of teaching theoretical content on endodontics at undergraduate level. Undoubtedly, new teaching methodologies have been incorporated into undergraduate training of endodontics.

The theoretical contents taught in the subject of endodontics are only mentioned in five of the studies, four carried out in Europe (Al Raisi et al., 2019; Mergoni et al., 2022; Sacha et al., 2021; Segura-Egea et al., 2021), and other in Canada (Goyal et al., 2024), showing that almost all dental schools included the contents indicated in the ESE Undergraduate Curriculum Guidelines for Endodontology (Baaij et al., 2024). This is a very important point, taking into account that in endodontics, students' practical skills and theoretical knowledge are significantly correlated (Haupt & Kanzow, 2023). Non-vital bleaching, that was not included in the curriculum of some schools in the UK twenty-seven years ago (Qualtrough & Dummer, 1997), now it is included in almost 100% of dental schools (Al Raisi et al., 2019; Mergoni et al., 2022; Sacha et al., 2021; Segura-Egea et al., 2021).

Preclinical endodontic practices are taught in all dental schools. This result contrasts sharply with that of a previous survey conducted in German universities (Sonntag et al., 2008), in which was found that PC endodontic training varied considerably because of differences in program design, staff and course content. Regarding the type of root canals used in pre-clinical practice, natural teeth were used in all dental schools in Spain (Segura-Egea et al., 2021), and Saudi Arabia (Narayanaraopeta & Al Shwaimi, 2015), in most dental schools in Austria, Germany, Switzerland, Italy and Malaysia (Baharin & Omar, 2021; Mergoni et al., 2022; Sacha et al., 2021), and in at least 70% of schools in the United Kingdom (Al Raisi et al., 2019) and Canada (Goyal et al., 2024). Artificial teeth, plastic teeth and canals in acrylic blocks were used in less than 50% of schools.

Few studies indicate the type of endodontic treatments that students perform in pre-clinical practices. Root canal treatment (RCT) in one-rooted and multi-rooted teeth are performed in all dental schools in Spain (Segura-Egea et al., 2021), Italy (Mergoni et al., 2022), United Kingdom (Al Raisi et al., 2019), Austria, Germany and Switzerland (Sacha et al., 2021) and Canada (Goyal et al., 2024).

Re-treatments were carried out in almost 50% of Italian dental schools (Mergoni et al., 2022), in one third of the schools in Spain (Segura-Egea et al., 2021) and Saudi Arabia (Alobaid et al., 2022), and only in 10% of Canadian dental schools (Goyal et al., 2024).

Concerning the types of endodontic treatments in clinical training, RCT in single-rooted teeth was the endodontic treatment done in more than 90% of all dental schools (Al Raisi et al., 2019; Algahtani et al., 2022; Alobaid et al., 2022; Segura-Egea et al., 2021). Vital pulp therapy was carried out by endodontic students in more than 90% of schools in Spain (Segura-Egea et al., 2021) and Saudi Arabia (Algahtani et al., 2022; Alobaid et al., 2022), and by almost 50% in Italian universities (Mergoni et al., 2022). In view of these results, the objectives set by the ESE in the Undergraduate Curriculum Guidelines for Endodontology, i.e. Students should be competent in performing good-quality root canal treatment and at preserving vital pulp functions by the implementation of vital pulp therapies, including indirect pulp capping, direct pulp capping, partial pulpotomy and full pulpotomy (Baaij et al., 2024), seems that they are being fulfilled.

Non-vital bleaching was carried out in a third of dental schools in Italy and Spain (Mergoni et al., 2022; Segura-Egea et al., 2021). Most studies show that endodontic surgery is outside of clinical endodontic practices in most countries. Endodontic surgery is probably covered in most dental schools in postgraduate endodontic teaching.

3.3. Root Canal Treatment Protocol Used in Undergraduate Endodontic Teaching

Data on RCT protocol used in undergraduate teaching were found in ten studies (Al Raisi et al., 2019; Algahtani et al., 2023; Baharin & Omar, 2021; da Costa Ferreira et al., 2021; Goyal et al., 2024; Mergoni et al., 2022; Narayanaraopeta & Al Shwaimi, 2015; Rech et al., 2022; Sacha et al., 2021; Segura-Egea et al., 2021) (Table 4), but two of them provided very few data (da Costa Ferreira et al., 2021; Rech et al., 2022), and another study only provided data about pre-clinical practices (Sacha et al., 2021).

A study carried out in Malaysia (Baharin & Omar, 2021) was the only one who provided data on the use of the rubber dam, specifying that its use was compulsory in all Malaysian dental schools. The fact that only one of the studies investigated the use of rubber dam in endodontics, probably indicates that its use is considered so routine that the possibility of teaching RCT without their use is ruled out.

For determining working length in clinical practice, electronic apex locators together with periapical radiograph are used in most of the dental schools (Al Raisi et al., 2019; Baharin & Omar, 2021; Mergoni et al., 2022; Narayanaraopeta & Al Shwaimi, 2015; Rech et al., 2022; Segura-Egea et al., 2021).

Instrumentation is taught using NiTi rotary files in almost all dental schools in Europe (Sacha et al., 2021) and Canada (Goyal et al., 2024), being Protaper Gold the system used in two thirds of dental schools (Al Raisi et al., 2019; Goyal et al., 2024; Segura-Egea et al., 2021). An earlier study carried out twenty years ago, including 16 French undergraduate dental schools (Arbab-Chirani & Vulcain, 2004), showed that rotary NiTi files were already used on endodontic teaching in 81% of French schools. However, in other countries NiTi rotary files were used only in about half of dental schools (Algahtani et al., 2023; da Costa Ferreira et al., 2021).

Sodium hypochlorite, at different concentrations, was the irrigating solution used by most schools in endodontic clinical practice. EDTA was also used in a large percentage of schools as a second irrigating solution (Al Raisi et al., 2019; Baharin & Omar, 2021; Mergoni et al., 2022; Segura-Egea et al., 2021). In PC practices some dental schools use chlorhexidine as an irrigating solution (Sacha et al., 2021).

Calcium hydroxide was the most used intracanal medicament around the world, being used as intracanal medicament in all dental schools in United Kingdom (Al Raisi et al., 2019), Spain (Segura-Egea et al., 2021), Italy (Mergoni et al., 2022) and Malaysia (Baharin & Omar, 2021), in more than 80% in Austria, Germany and Switzerland (Sacha et al., 2021) and in 60% of schools in Saudi Arabia (Algahtani et al., 2023) and Canada (Goyal et al., 2024).

Regarding the obturation technique taught, cold lateral compaction was the root-filling technique trained in most dental schools (Algahtani et al., 2023; Baharin & Omar, 2021; Narayanaraopeta & Al Shwaimi, 2015; Sacha et al., 2021; Segura-Egea et al., 2021). Warm vertical compaction was the second technique taught, being the most widely taught technique in Canadian dental schools (Goyal et al., 2024). The single cone technique is rarely taught, being used by less than 30% of schools (Al Raisi et al., 2019; Algahtani et al., 2023; Baharin & Omar, 2021; Mergoni et al., 2022; Segura-Egea et al., 2021). The data show that cold lateral compaction technique remains the standard root filling technique in most dental schools. Despite widespread commercial support for gutta-percha support systems, these are rarely used in endodontic teaching.

Taking together the results of these studies, it can be concluded that the clinical protocol followed for RCT worldwide is quite homogeneous, differing especially in the type of technique used for obturation of the root canal system. As regards European dental schools in particular, the clinical protocols for RCT followed in the countries from which data have been found, show greater convergence than that found in a previous study conducted fifteen years ago (Gatley et al., 2009).

The definitive restoration of the treated tooth was carried out interchangeably by the student himself or by another in most dental schools (Al Raisi et al., 2019; Sacha et al., 2021; Segura-Egea et al., 2021).

3.4. Use of Contemporary Materials and Technologies in Endodontic Training

The use of modern technologies and materials in endodontics teaching was addressed by ten studies (Al Raisi et al., 2019; Algahtani et al., 2023; Baharin & Omar, 2021; Brown et al., 2020; Coelho & Rios, 2023; da Costa Ferreira et al., 2021; Goyal et al., 2024; Mergoni et al., 2022; Sacha et al., 2021; Segura-Egea et al., 2021) (Table 5).

Five studies reported data on the use of calcium silicate-based cements (CSBC) (Al Raisi et al., 2019; Algahtani et al., 2023; Goyal et al., 2024; Sacha et al., 2021; Segura-Egea et al., 2021). Although the use of CSBC in preclinical practices was uncommon (Al Raisi et al., 2019; Sacha et al., 2021), probably because of its high price, in clinical practices CSBC were used in most dental schools (Al Raisi et al., 2019; Algahtani et al., 2023; Segura-Egea et al., 2021). The use of bioceramic sealers in undergraduate endodontic teaching only is reported in the study carried out in Canada (Goyal et al., 2024), being used in 20% of Canadian dental schools.

Regarding the use of cone beam computed tomography (CBCT), based on the data provided by the studies that have investigated its use in teaching endodontics (Al Raisi et al., 2019; Algahtani et al., 2023; Baharin & Omar, 2021; Coelho & Rios, 2023; Goyal et al., 2024), it can be concluded that CBCT is used in less than 50% of dental schools. This result indicates that CBCT has not yet been incorporated into the undergraduate teaching of endodontics. So, strategies must be considered to allow the integration of CBCT in clinical training use.

A study carried out in Brazil show that the minority of the dental schools (34%) owned a CBCT machine (Coelho & Rios, 2023). This result contrasts with those of dental schools in the U.S.A. and the U.K., which in 2012 already had CBCT in 89% and 63% of cases, respectively (Parashar et al., 2012). However, the same study showed that none of the dental schools surveyed in the U.K. provide training to dental students during the BDS curriculum (Parashar et al., 2012).

Magnification, and especially the use of the operating microscope, represents another addition to the practice of endodontics that has substantially improved its quality and results. However, the results of the review show that, in most countries, it has not yet been incorporated into undergraduate teaching of endodontics. Less than more than 50% of dental schools use magnification (Al Raisi et al., 2019; Algahtani et al., 2023; da Costa Ferreira et al., 2021; Goyal et al., 2024; Mergoni et al., 2022; Sacha et al., 2021; Segura-Egea et al., 2021). On the contrary, in United Kingdom and Ireland operating microscope is used in undergraduate endodontic clinical training in all dental schools (Brown et al., 2020). The high cost and lack of staff training could explain, at least in part, these results (Brown et al., 2020).

Finally, seven studies reported data about the use of ultrasonic devices in undergraduate endodontic teaching (Al Raisi et al., 2019; Algahtani et al., 2023; da Costa Ferreira et al., 2021; Goyal et al., 2024; Mergoni et al., 2022; Sacha et al., 2021; Segura-Egea et al., 2021). The results of these studies show that ultrasound is rarely used in teaching endodontics in Spain (Segura-Egea et al., 2021), Austria, Germany, and Switzerland (Sacha et al., 2021), Canada (Goyal et al., 2024) and Saudi Arabia (Algahtani et al., 2023). On the contrary, the studies carried out in the United Kingdom (Al Raisi et al., 2019) and Italy (Mergoni et al., 2022) found a high percentage of ultrasound use, around 80%, in undergraduate endodontic clinical practices. Again, these results indicate the need to review programs and increase budgets of dental schools to be able to incorporate ultrasonic devices into the undergraduate endodontics program.

3.5. Assessment Methodology in Endodontic Training

As a final point, seven studies (Al Raisi et al., 2019; Algahtani et al., 2022; Goyal et al., 2024; Mergoni et al., 2022; Narayanaraopeta & Al Shwaimi, 2015; Sacha et al., 2021; Segura-Egea et al., 2021) reported data on the methods used to evaluate the learning of undergraduate students in endodontics (Table 6). As indicated in the undergraduate curriculum guidelines for Endodontology, recently published by the ESE (Baaij et al., 2024), the competence of students to reach the correct diagnosis and perform vital pulp therapies and root canal treatment on uncomplicated anterior and posterior teeth should be formally assessed before allowing them to graduate. The assessment of theoretical content was carried out by means of short questions in half of the dental schools in Saudi Arabia and Canada (Goyal et al., 2024; Narayanaraopeta & Al Shwaimi, 2015). In contrast, in Austria, Germany and Switzerland, oral examinations are used by one third of the schools (Sacha et al., 2021).

For the evaluation of pre-clinical practices, the practical competency exam was used in Saudi Arabia (Algahtani et al., 2022) and Canada (Goyal et al., 2024). Most dental schools required a minimum number of RCT in preclinical practices (Al Raisi et al., 2019; Algahtani et al., 2022; Sacha et al., 2021; Segura-Egea et al., 2021).

Clinical training were evaluated by clinical competency exams (Algahtani et al., 2022; Goyal et al., 2024), and more than 50% of dental schools also required a minimum number of treatments (Al Raisi et al., 2019; Mergoni et al., 2022; Segura-Egea et al., 2021). However, for students to achieve the appropriate level of competence in endodontics, the evaluation of the quality and consistency of student performance is more important than the number of treatments performed.

4. Conclusions

This systematic review aimed to show the current situation of undergraduate endodontic teaching worldwide. The data found in the published studies show great consistency and, compared with the data found in studies carried out decades ago, allow us to conclude that the quality of endodontic teaching in dental schools around the world has increased substantially. However, there is still room for improvement in some aspects, especially the incorporation of new technologies and materials into the teaching of Endodontics at the undergraduate level. This is the case of magnification, ultrasound and CBCT. The publication by the European Society of Endodontology of the Undergraduate Curriculum Guidelines for Endodontology (Baaij et al., 2024), with numerous recommendations on the scope of endodontic education, may be the appropriate instrument to continue improving and homogenizing undergraduate teaching of Endodontics throughout the world.