NATURAL VERSUS ARTIFICIAL TEETH IN PRECLINICAL ENDODONTIC TRAINING

Abstract

Keywords: endodontics, dental education, natural tooth, artificial tooth, preclinical endodontic training. 1.INTRODUCTION Endodontic treatment success is affected by the obturation technical quality [1-4]. Since preclinical endodontics is one of the core courses in dental schools, the training provided to undergraduate students is extremely important. [...]there is a potential risk of crossinfection, associated with the use of this model for exercises [7-10]. [...]a recent systematic review comparing natural and artificial teeth reported a scarcity of studies on this subject [12]. [...]our aim was to objectively compare the root canal treatment quality achieved with the practice of using natural and artificial teeth by undergraduate preclinical endodontics students, to determine whether artificial teeth are suitable models for training. 2.MATERIALS AND METHODS The research was reviewed and approved by The College of Dentistry Research Center (CDRC), King Saud University, Riyadh, Saudi Arabia (FR 0497). [...]the use of natural teeth is still necessary, since it provides training on more complex and curved canals, that resembles clinical scenarios. [...]within the limitation of this study, the combination of both models would be recommended 5.CONCLUSIONS Artificial teeth are suitable for a preclinical endodontic training model and ensure predictable technical outcomes in comparison with artificial teeth.

Headnote

Abstract

Introduction. The aim is to objectively compare the root canal treatment quality in training performed using natural and artificial teeth by undergraduate preclinical students. Materials and methods. A total of 265 preclinical procedures performed on natural (134 cases) and artificial teeth (131 cases) over four consecutive projects was assessed. Radiographic evaluations were performed by two experienced endodontists to assess the technical quality of root obturation and the presence of iatrogenic errors. A P value < 0.05 was deemed statistically significant. Results and discussion. Artificial teeth were correlated with a significantly higher number of acceptable cases and significantly fewer iatrogenic errors in comparison with natural teeth. Natural teeth were correlated with significantly more under-filled cases in comparison with artificial teeth with significantly more ledges, which was a significantly correlated cause of under-filling. Conclusions. Artificial teeth are suitable models for preclinical endodontic training, since they ensure predictable technical outcomes in comparison with natural teeth.

Keywords: endodontics, dental education, natural tooth, artificial tooth, preclinical endodontic training.

1.INTRODUCTION

Endodontic treatment success is affected by the obturation technical quality [1-4]. Since preclinical endodontics is one of the core courses in dental schools, the training provided to undergraduate students is extremely important. Adequate training would allow future dentists to provide appropriate root canal treatment to their patients. However, the low quality of root canal obturation performed by undergraduate students has been reported previously [5,6]. Therefore, intensive preclinical endodontic training is required for them.

Traditionally, extracted natural teeth were used for endodontic preclinical training for decades. They were the sole model used for this purpose, since they offered advantages such as their natural canal anatomy, color, hardness, and radiographic presentation. However, acquisition of suitable natural teeth for these exercises is challenging. Their selection is also difficult because of their variability and complexity. Moreover, there is a potential risk of crossinfection, associated with the use of this model for exercises [7-10]. In addition, there are ethical concerns related to the use of extracted natural teeth, especially if an alternative training model is available.

In 1991, Dummer et al. [11] introduced artificial canals that reproduce root canal curvature in uniform resin blocks for both teaching and research purposes. The clear resin allows visualization of the endodontic procedure. Furthermore, this model allowed standardization of the degree of canal curvature, length, and diameter [11]. However, it did not allow practice on the access cavity part, and it could not accurately reproduce dentin hardness or radiopacity [12]. To overcome these drawbacks, artificial teeth were developed. The artificial tooth models commercially available at present offer solutions to many of the challenges encountered in natural teeth. The primary benefits provided by this model are availability and uniformity. Furthermore, the artificial tooth model poses no risk of cross-infection. The use of these models also resolves the ethical concerns related to the use of natural teeth for training.

Previous surveys have reported that, although there is no universal teaching model in dental schools, undergraduate endodontic exercises commonly use a combination of natural extracted and artificial teeth [13,14]. However, a recent systematic review comparing natural and artificial teeth reported a scarcity of studies on this subject [12]. Thus, our aim was to objectively compare the root canal treatment quality achieved with the practice of using natural and artificial teeth by undergraduate preclinical endodontics students, to determine whether artificial teeth are suitable models for training.

2.MATERIALS AND METHODS

The research was reviewed and approved by The College of Dentistry Research Center (CDRC), King Saud University, Riyadh, Saudi Arabia (FR 0497). It involved four consecutive projects conducted as part of the preclinical endodontic course at King Saud University in 2018. Sixtyeight students were registered for that course, but one student dropped after the first project. The sequence of projects was as follows: first natural (N1), first artificial (A1), second natural (N2), and second artificial (A2). The study included only single canals of natural or artificial teeth (Real-T Endo, Acadental Lenexa, KS, USA).

265 preclinical cases were divided across the four projects: N1 (68 cases), A1 (64 cases), N2 (66 cases), and A2 (67 cases). One student who dropped from the course was counted in project N1, while three students did not attend project A1. One case in project N2 was excluded because it involved two canals. Two calibrated endodontists with more than five years of experience performed radiographic evaluations of the included cases by using a computer visualization software (Planmeca Romexis, Planmeca, Helsinki, Finland). A pilot study was conducted on twenty randomly selected natural and artificial teeth (10 of each) twice, with an one-week interval between the two readings.

The instrumentation technique used for teeth preparation involved step-back hand instrumentation using 0.02-taper stainlesssteel K-files (Dentsply Maillefer). For obturation, the lateral compaction method was performed using 0.02-taper gutta-percha cones (DENTSPLY DeTrey GmbH) and AH-26 sealer (DENTSPLY DeTrey GmbH). Straight buccolingual radiographs were taken during procedures by a dental X-ray unit (Planmeca ProX™; Planmeca®, Helsinki, Finland) at 70 kVp, 10 mA, and 0.20-s exposure time and a size-2 digital sensor (Planmeca ProSensor HD digital sensor system; Planmeca®, Helsinki, Finland).

The criteria proposed by Khabbaz et al. [5] for radiographic evaluation were adopted. These criteria covered the technical quality of root obturation and the occurrence of iatrogenic errors, as shown in Table 1. Statistical analysis was performed by SPSS software, version 20.0 (SPSS, Inc., Chicago, IL, USA). Frequencies of cases corresponding to each criterion were counted and presented descriptively. Pearson's chi-squared test and Fisher's exact test were used to find the statistical significance of the differences between natural and artificial teeth groups and their technical associations. A P value < 0.05 was deemed statistically significant.

3.RESULTS

The calibration measurements of inter- and intra-examiner reliability by using Cronbach's alpha test indicated a high reliability among examiners (0.86-0.94, p < 0.05). The study included 134 cases involving natural teeth and 131 cases involving artificial teeth. The technical quality of root obturation and the iatrogenic errors showed significant correlations with tooth type (P < 0.05), as presented in Tables 2 and 3. Artificial teeth were correlated with a significantly higher number of acceptable cases in comparison with natural teeth (P < 0.001) and with significantly fewer iatrogenic errors (P < 0.001). Natural teeth were correlated with significantly more under-filled cases compared to artificial teeth (P < 0.001) and with significantly more cases of ledges, which was a significantly correlated cause of underfilling (P < 0.01).

Data is presented as case count and percentages. a Statistically significant differences (P < 0.05) between natural and artificial teeth

When evaluating the progress over projects, the results indicated a significant improvement in student performance in relation to tooth type (P < 0.05). In assessments of the technical quality of root obturation, a statistically significant increase in the number of acceptable cases was observed in natural (P = 0.02) and artificial teeth (P < 0.001). There was a statistically significant decrease in the number of underfilled cases in natural teeth (P = 0.01) and the number of over-filled cases in artificial teeth (P < 0.001), as shown in Table 4. In assessments of iatrogenic errors, a statistically significant increase was observed in the number of cases without iatrogenic errors in both natural (P = 0.02) and artificial teeth (P = 0.05), as shown in Table 5.

4.DISCUSSION

Previous researches have compared operator's perception of artificial teeth as a training model for undergraduate from different perspectives. The main advantages of natural over artificial teeth were in their physical properties [7-10]. However, artificial teeth offered the advantages of availability and uniformity [12]. The present study objectively compared natural and artificial teeth as training models for undergraduate students by using the radiographic evaluation criteria reported previously [5].

When comparing artificial to natural teeth, natural teeth showed more cases of ledges, which represented a significantly correlated cause of under-filling. This can be related to the curvature and complexity in the root canal system of natural teeth, which make such training models more realistic but also more difficult for beginners.

Artificial teeth were correlated significantly with more acceptable cases and with less iatrogenic errors than natural teeth. This can be attributed to the lower anatomical complexity, e.g., fewer curvatures and absence of calcified canals. The reduced complexity allowed undergraduate students to perform root canal treatment to the full working length, with minimum iatrogenic errors. This can be an advantage to students starting to perform endodontics, since such procedures can help them understand the ideal scenario before they are introduced to complex cases (which remain essential in a further stage, to ensure that students simulate as many clinical scenarios as possible). The results of this study agree with the findings obtained in another study, that reported better results in the artificial tooth group in preclinical training [10]. Tchorz further reported that training on artificial teeth did not affect the clinical scenarios. When comparing student's improvement between artificial and natural teeth, we observed a significant progress, that could be related to the process of learning by performing iatrogenic errors in both groups, which supports the idea of progressive learning using both models: artificial and natural teeth.

A limitation of this study was that it was confined to only one type of artificial teeth and the results may change, depending on the manufacturing technique. Future studies should attempt at comparing different types of artificial teeth, including 3D-printed teeth. The use of different obturation techniques can also influence the results of such studies.

There is a scarcity of studies regarding the use of artificial teeth as training models preclinically. Bitter et. al. reported that training on artificial teeth could prepare the students to work on natural teeth, but the findings should be regarded with caution [8]. A recent systematic review concluded that preclinical training on artificial teeth could produce similar outcomes in comparison with natural teeth [12]. This study found out some advantages associated with the artificial teeth model, since it provides an available and uniform model that enables students to perform root canal treatment to the full length with less ledges. However, the use of natural teeth is still necessary, since it provides training on more complex and curved canals, that resembles clinical scenarios. Therefore, within the limitation of this study, the combination of both models would be recommended

5.CONCLUSIONS

Artificial teeth are suitable for a preclinical endodontic training model and ensure predictable technical outcomes in comparison with artificial teeth. We recommend combining of both models in preclinical endodontic training, to give students more chances to practice and maximize the benefits from both models.

Acknowledgments

The authors thank The College of Dentistry Research Center (CDRC), King Saud University, Riyadh, Saudi Arabia (no. FR 0497), for its support of the realization of this project.

References

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