Teaching Model for Artificial Teeth and Endodontic Apex Locators

A bibliometric comparison of undergraduate and postgraduate endodontic education publications: The topics, trends, and challenges

OBJECTIVES

This study employs bibliometric analysis to compare knowledge units and main topics in undergraduate and postgraduate endodontic education, aiming to identify similarities, differences, and connections. The insights gained are expected to inform the future of two-stage education to enhance continuity, highlighting evolving trends, challenges, and development directions.

METHODS

Citation data were retrieved from the Web of Science Core Collections (WOSCC) database and non-WOSCC databases with two separate search formulas. VOSviewer and CiteSpace were used to analyze the distribution of research by publication years, citation-sources, co-authorship network of authors and countries, and clusters of keywords.

RESULTS

The focus on undergraduate education preceded postgraduate education by nearly a decade. The United Kingdom has emerged as the most prominent contributor to endodontic literature at both levels, with the International Endodontic Journal representing the most voluminous and cited resource in this domain. Dummer is recognized as the most prolific author in undergraduate endodontic education, while Gulabivala spearheads the most extensive cluster of postgraduate education. Keywords clustering analysis reveals that undergraduate education places greater emphasis on fundamental knowledge, while postgraduate education concentrates more on clinical practice. Descriptive analyses from non-WOSCC databases align with the topics and findings from WOSCC-based bibliometric analysis.

CONCLUSION

This bibliometric analysis revealed the emphasis on fundamental knowledge and teaching techniques at the undergraduate level versus advanced clinical knowledge and techniques at the postgraduate level, which originated from different learning aims and contexts. Updating the curriculum to meet the latest practices and innovations is crucial for aligning learning objectives with current and future needs, and the connection between the two levels remains a central challenge in endodontic education.

Students' perception of three-dimensionally printed teeth in endodontic training

INTRODUCTION

In endodontic education, there is a need for thorough training prior to students embarking on clinical treatment. The aim of this study was to use three-dimensional printing technology to create a new model and to compare its suitability for training purposes with resin blocks and extracted teeth.

MATERIALS AND METHODS

Multi-jet-modelling (MJM) produced the 3D model replicating a common difficulty in root-canal morphology. An evaluation study comprising 88 students was run in the sixth semester (summer 2018 and winter 2018/2019). A new questionnaire assessed students' perception of training models and educational environment. Welch's t-test analysed significant differences.

RESULTS

The most pronounced differences between models were noted when rating material hardness, radiopacity, root-canal configuration and suitability for practising. Students estimated their learning outcome as greater with 3D-printed teeth compared to resin blocks. Three-dimensionally printed teeth received significantly lower ratings with regard to enthusiasm, the learning of fine motor skills and spatial awareness, when compared to human teeth (p ≤ .001). However, 3D-printed teeth were appreciated for additional benefits, such as their cleanliness, availability and standardisation of training opportunities with complex root-canal configurations.

CONCLUSION

Students preferred extracted human teeth to 3D-printed teeth with respect to their physical characteristics and training experience. However, educational advantages may compensate for the shortcomings. The new questionnaire proved both adequate and accurate to assess the models and educational environment in endodontic training. The new 3D-printed teeth enhanced the learning opportunities.

A simulation model used in teaching denture border adjustment: Randomized controlled trial

OBJECTIVES

The goal was to propose a new simulation model as a training tool in complete denture (CD) flange adjustment and to evaluate if the model can improve student competencies in different learning domains.

METHODS

Fourth-year undergraduate dental students (n = 100) were equally divided into control and test groups. Both groups received didactic instructions for CD post-insertion procedures, but the test group had additional simulation training using modified working casts. Both groups then performed CD flange adjustment on real patients, and their skills were evaluated using a specific checklist. The data were assessed by independent samples t-test and a chi-square test at α = 0.05.

RESULTS

The students in the test group showed significantly better overall performance (57.94%) compared with the control group (30.14%) in clinical post-insertion CD flange adjustment procedures (p < 0.001). However, the psychomotor skills of the male students in the test group were not significantly influenced (p = 0.268). Considering the competencies for different tasks, more students that were competent were present in the test group compared to those in the control group regarding most of the knowledge (p ≤ 0.012) and all of the cognitive skill tasks (p ≤ 0.021). More students were competent for half of the psychomotor skill tasks (p ≤ 0.027). However, when considering gender, the number of competent male students was significantly greater in the test group only for one of the psychomotor tasks.

CONCLUSION

The simulation model significantly improved the overall clinical skills of the students, allowing them to learn the common CD post-insertion maintenance procedures before performing the procedure clinically.

Influence of embedding media on the accuracy of working length determination by means of apex locator: an ex vivo study

The aim of this research was to determine ex vivo the influence on accuracy of five different embedding media, for investigative and educational purposes, and one electronic apex locator. 110 human extracted mature roots of permanent single-rooted human teeth were used. The roots were embedded in alginate, stick sponge, 2% agar–agar and 6% and 12% gelatin. The actual working length to the physiological foramen was determined under a stereo-microscope (16 ×) and the electronic working lengths with the Elements Diagnostic Unit and a K-file ISO 10. The accuracy ranges of the accumulated measurements, when allowing a ± 0.5 mm tolerance, went from 98.2% (6% and 12% gelatin), 93.7% (alginate), 92.8% (2% agar–agar) to 91.7% (sponge). The exact measurements at the physiological foramen ranged from 80.0% (6% gelatin), 76.5% (2% agar–agar), 71.8% (12% gelatin), 68.2% (alginate) to 64.5% (sponge). Although relatively seldom (n = 24), measurements with deviations of more than ± 0.5 mm were also observed; thus, the accuracy of the working length determination results per se can be considered as clinically acceptable. The results of this research allow a recommendation of the investigated embedding media for electronic working length determination models for educational and research purposes in endodontics.

The accuracy of electronic apex locators for determining working length: An in vitro study with artificial teeth

This study aimed to determine the accuracy of four electronic apex locators (EALs) (I-Root, Propex Pixi, Novapex and Bassi iRoot Apex), using artificial mandibular and maxillary permanent molars. The root length (RL) from 40 artificial teeth was initially determined with Kerr hand files. Then, the electronic RL were obtained for the same root canals with each EAL, and the results were compared with those obtained using hand files. The accuracy of the EALs was determined through analysis of the divergences observed in relation to the lengths obtained with files. All EALs were effective for determining the RL in the artificial teeth, showing results similar to those obtained by hand. The Bassi iRoot Apex had higher accuracy (96.7%) than the Propex Pixi (89.1%) and Novapex (85.8%) (P < 0.05). Based on the results, all EALs tested had a similar performance, and artificial teeth may be used to determine the accuracy of these devices.

Perception of a modular 3D print model in undergraduate endodontic education

AIM

To evaluate a modular 3D print training dental model with embedded human teeth and electronic working length determination for undergraduate endodontic education.

METHODOLOGY

Cone-beam volume tomography data of a human skull were transferred into stereolithographic (STL) data, and a customizable modular 3D print model with individually removable sextants and teeth was generated for the use in commercially available phantom heads. Each of sixty-eight students performed a complete root canal treatment on an extracted human tooth. Working lengths were determined with electronic apex locators (EAL) and verified radiographically. Subsequently, an evaluation was carried out with regard to the difficulty of the working steps access cavity preparation, working length determination, root canal preparation/irrigation and canal filling, and these steps were compared to commonly used benchtop models. Additionally, the agreement of electronic and radiographic working length determination was assessed and analysed statistically with the chi-square test.

RESULTS

A total of 68 teeth (20 incisors, 26 premolars and 22 molars) with 127 root canals were treated. In total, 87% of the students considered the modular 3D print model considerably more demanding than the conventional benchtop model. Overall, 96% felt better prepared for the clinical situation, 92% felt markedly reduced stress levels during endodontic practice in the subsequent clinical courses, and 93% of the students suggested the model should be used in future preclinical endodontic training. The preradiographic use of EAL resulted in 85% of the cases having radiographically acceptable working length determination within 0-2 mm from the radiographic apex. Readings more than 2 mm from the apex or beyond were significantly more common in molars than in premolars and incisors (P < 0.05).

CONCLUSIONS

The vast majority of students rated the modular 3D print training model positively despite it being more demanding. They also recommended its use in preclinical teaching and training. The model allowed a more realistic simulation of the clinical situation with a simultaneous use of EALs and led to reduced stress levels in endodontic treatment in the subsequent clinical courses.

A novel anatomical ceramic root canal simulator for endodontic training

INTRODUCTION

Endodontic therapy is often complicated and technically demanding. The aim of this study was to develop a reproducible biomimetic root canal model for pre-clinical and postgraduate endodontic training.

MATERIAL AND METHODS

A specific ceramic shaping technique (3D printing and slip casting of a root canal mould) was developed to reproduce canal systems with the desired shape and complexity using a microporous hydroxyapatite (HAp)-based matrix. The microstructural morphology, pore size and porosity, as well as the Vickers microhardness of the ceramic simulators (CS) were assessed and were compared with natural dentin and commercial resin blocks. The reproducibility of the root canal shapes was assessed using the Dice-Sørensen similarity index. Endodontic treatments, from refitting the access cavity to obturation, were performed on the CS. Each step was controlled by radiography.

RESULTS

Many properties of the CS were similar to those of natural dental roots, including the mineral component (HAp), porosity (20%, porous CS), pore size (3.4 ± 2.6 μm) and hardness (120.3 ± 18.4 HV).

DISCUSSION

We showed that it is possible to reproduce the radio-opacity of a tooth and variations in root canal morphology. The endodontic treatments confirmed that the CS provided good tactile sensation during instrumentation and displayed suitable radiological behaviour.

CONCLUSIONS

This novel anatomic root canal simulator is well suited for training undergraduate and postgraduate students in endodontic procedures.

Ex vivo investigation on the postoperative integrity of the apical constriction after the sole use of electronic working length determination

AIM

The present study investigated the accuracy of root canal preparation with regard to the integrity of the apical constriction (AC) using two different working length determination approaches: (1) the electronic method of working length determination (EWLD), and (2) the radiologic "gold standard" method (GS).

METHODOLOGY

Simulation models were constructed by arranging extracted human teeth by means of silicon bolstered gingiva masks, along with a conductive medium (alginate). Electronic working length determination (group 1; EWLD) and radiologic plus initial electronic working length determination for posterior comparability (group 2; GS) preceded manual root canal preparation of teeth in both groups. Master cones were inserted according to working lengths obtained from the group specific method. Subsequently, root apices (n=36) were longitudinally sectioned using a diamond-coated bur. The distance between the achieved apical endpoint of the endodontic preparation and the apical constriction (AC) was measured using digital photography. Then, distances between radiologically identified apical endpoints and AC (GS-AC) were compared with the corresponding distances EWLD-AC. Moreover, the postoperative status of the AC was examined with regard to both preparation approaches.

RESULTS

Differences between distances GS-AC and EWLD-AC were not statistically significant (p >0.401) (Mann-Whitney-U). Among EWLD samples, 83% of the master cones exhibiting tugback at final insertion terminated close to the apical constriction (±0.5 mm), and no impairment of the minor diameter's integrity was observed.

CONCLUSIONS

The sole use of EWLD allowed for a high accuracy of measurements and granted precise preparation of the apical regions.

A new technique to make transparent teeth without decalcifying: description of the methodology and micro-hardness assessment

Diaphanisation and other in vitro endodontic models (i.e., plastic blocks, micro-CT reconstruction, computerised models) do not recreate real root canal working conditions: a more realistic endodontic model is essential for testing endodontic devices and teaching purposes. The aim of this study was to describe a new technique to construct transparent teeth without decalcifying and evaluate the micro-hardness of so treated teeth. Thirty freshly extracted teeth were randomly divided into three groups as follows: 10 non-treated teeth (4 molars, 3 premolars, 3 incisors; control group - G1), 10 teeth were diaphanised (4 molars, 4 premolars, 2 incisors - G2) and 10 teeth were treated with the new proposed technique (2 molars, 6 premolars, 2 incisors - G3). Vickers hardness tester (MHT-4 and AxioVision microscope, Carl Zeiss, 37030 Gottingen, Germany - load=50 g, dwell time=20s, slope=5, 50× magnification) was used to determine microhardness (Vickers Hardness Number - VHN). Statistical analysis was performed using the Intercooled Stata 8.0 software (Stata Corporation, College Station, TX, USA). Only groups 1 and 3 could be tested for hardness because diaphanised teeth were too tender and elastic. Differences in enamel VHN were observed between G1 (mean 304.29; DS=10.44; range 283-321) and G3 (mean 318.51; DS=14.36; range 295.5-339.2) - (p<0.05); differences in dentine VHN were observed between G1 (mean 74.73; DS=6.62; range 63.9-88.1) and G3 (mean 64.54; DS=5.55; range 51.2-72.3) - (p<0.05). G3 teeth presented a slightly lower VHN compared to G1, probably due to some little structural differences among groups, and were dramatically harder than the diaphanised teeth. The described technique, thus, can be considered ideal for testing endodontic instruments and for teaching purposes.