Design and working of "Vasundhara's model for elementary endodontic training": A novel preclinical endodontic model.

Context: This is a novel preclinical endodontic model "Vasundhara's model for elementary endodontic training," featuring easy and convenient way for enhancing the skills of elementary endodontic procedures, simulating the clinical situation for endodontic teaching purposes. This article highlights the need, steps of fabrication of the model, and usage of the same for the universal benefit of the learners of endodontic techniques. Aims: The aim is to describe the design and usage of a novel preclinical endodontic model which is simple, convenient, easy to fabricate, and cost-effective. Settings and Design: Extracted teeth were selected and a pan radiograph was taken. Alginate was poured into metal jaws, followed by embedding of the teeth. Dental stone was then coated over the alginate. This assembly was then screwed to phantom head. A wire was attached to phantom head contacting the alginate for completing the circuit, forming an arc to which lip clip of apex locator could be attached. Conclusions: This novel cost-effective model for practicing preclinical endodontic techniques is simple, easy to design, and is a step forward toward mastering endodontic techniques. Copyright:

INTRODUCTION

Prerequisites for successful endodontic treatment are accurate access opening, working length determination, biomechanical preparation, and complete three-dimensional obturation.[1]

To master the skills required to provide a successful endodontic therapy in patients, the endodontic preclinical curriculum is an important step.[2] The quantity and quality of endodontic education have a significant impact on the treatment outcome.

Various models for practicing preclinical endodontic procedures have been designed, but their fabrication is time-consuming, also they are cumbersome to prepare and are quite expensive (explained in discussion).[134]

Therefore, the purpose of this report is to describe a novel preclinical endodontic model, “Vasundhara's Model for Elementary Endodontic Training (V-MEET”), which is simple, user-friendly, easy to fabricate, and is cost-effective.

MATERIALS AND METHODS

Extracted human maxillary teeth

Metal jaws

Alginate (Zelgan 2002, manufactured in Gurgaon, India, by DENTSPLY)

Dental stone (Gem Stone, manufactured by Shruti products, Rajkot, Gujarat, India)

Rubber dam (Coltene Dental Dam Kit, manufactured by Coltene Whaledent)

Endo Access Bur (manufactured by Dentsply Maillefer, Ballaigues, Switzerland)

Airotor (manufactured by NSK, Japan)

Endomotor (E-Connect Pro, manufactured by Changzhou Eighteeth Medical Technology Co., Ltd, China)

Electronic apex locator (E-Connect E-pex Pro, manufactured by Changzhou Eighteeth Medical Technology Co., Ltd, China)

Endo Gauge (manufactured by Dentsply Maillefer, Ballaigues, Switzerland)

Rotary files (Neoendo Flex Files, manufactured by Orikam Healthcare India Pvt. Ltd., Gurgaon, India)

Gutta-percha points (Neoendo Gutta-Percha Points, manufactured by Orikam Healthcare India Pvt. Ltd., Gurgaon, India)

Saline

Sodium hypochlorite

Cavit (manufactured by 3M ESPE, Germany).

Designing of the model

Extracted teeth were selected and arranged on a wax sheet [Figure 1a]

Figure 1

(a) Extracted teeth arranged on wax sheet. (b) Pan radiograph. (c) Alginate poured in metal jaw. (d) Teeth embedded in the alginate. (e) Dental stone coated over alginate. (f) Jaws screwed to phantom head with stainless steel wire

Pan radiograph of the entire set of teeth was taken [Figure 1b]

Alginate was mixed and poured into the metal jaws, so as to leave a space of 4–5 mm [Figure 1c]

The selected teeth were then embedded into alginate in such a way that only apical thirds of the teeth were embedded [Figure 1d]

Dental stone was then mixed, poured, and coated over alginate and the teeth till the cervical level [Figure 1e]

The mounted metal jaws were screwed to the base of phantom head. A stainless steel wire was attached between the base of phantom head and metal jaw contacting the alginate, thus completing the circuit. The other end of wire was attached beneath the mandibular jaw thus forming an arc which rested against the cheek of phantom head. Here, the lip clip of apex locator could be attached [Figure 1f]

Rubber dam was attached to the jaws.

The model is now ready to be used for practicing endodontic techniques in the preclinical setup.

Working of the model

Once the model was fabricated, access opening was done using Endo Access Bur [Figure 2a]

Figure 2

(a) Access opening. (b) Lip clip attached to wire. (c) Working length is taken. (d) Biomechanical preparation. (e) Obturation. (f) Disassembling the model. (g) Mounted assembly pushed out of jaws. (h) Postobturation pan radiograph

For working length determination, the lip clip of apex locator was attached to stainless steel wire, file clip was attached to the file which was then inserted into the canal [Figure 2b]

Working length reading was noted on the Endo Gauge [Figure 2c]

Biomechanical preparation was done using a rotary file system and canals were obturated [Figure 2d and e]

The model was then disassembled from phantom head. Rubber dam was removed first followed by the removal of metal jaws [Figure 2f]

The mounted assembly was pushed out from the jaws so that teeth could be easily removed [Figure 2g]

Postobturation pan radiograph was taken [Figure 2h].

DISCUSSION

A novel preclinical endodontic model was fabricated by embedding extracted human teeth in alginate within the metal jaws. In addition, dental stone was coated over it to provide rigidity and stability to the teeth.

Various models have been designed for use with electric apex locators in preclinical endodontic training.[3] One of the main components of these models is conductive medium used, which replaces the periodontal tissues.[5]

Ex vivo studies have examined different materials such as agar,[5] alginate,[6] saline,[7] gelatin,[8] and vegetable sponge.[9] Among these, alginate has been found to be superior for testing electric apex locators, due to its colloidal consistency and good electroconductive property.[10] It contains potassium alginate and calcium sulfate, which remains in a gel state, which allows ions to circulate freely thus conducting electric current. When various embedding media were compared, alginate provided the most coherent result.[10]

Since alginate shows imbibition and syneresis (dimensional changes), the working length determination was done immediately after the access cavity preparation for all the teeth. The model has to be stored in a bowl of water so as to prevent alginate from dehydration. It can be stored in water for a day. The dimensional change due to storage in water is not found to be significant as it does not affect the working length determination. If the alginate in the model appears dried, it has to be replaced. It is again a simple procedure to replace alginate, only the alginate part has to be removed from the metal mold and a freshly mixed alginate is poured over it to cover the root portion of the embedded teeth.

Various models have been designed previously for the purpose of practicing preclinical endodontics. Model designed by Balto et al.[4] was made using dental stone, silicone molds, and self-cure acrylic. It is quite technique sensitive to fabricate. Another model was designed by Vineeta et al.[1] was designed using agar duplicating material, plaster of Paris, sawdust, and alginate, which again is technique sensitive and time-consuming to fabricate. Another model, ModuPRO Endo[3] is a ready-to-use model marketed by Acadental USA, however, it is quite expensive. The key difference between V-MEET and other models is mainly the cost of materials required, time, and ease of fabrication, making V-MEET a suitable model that is least expensive and easy to fabricate compared to others.

The novel model designed in this report is quick and easy to fabricate. Furthermore, the cost of materials required for its fabrication is affordable. There is enough space for the arrangement of all 32 teeth, and it allows the application of rubber dam, thus making the learners exposed to clinical difficulties. Besides, this model allows the usage of electric apex locators. However, in situ radiography is not possible in the model.

CONCLUSION

This novel cost-effective model for practicing preclinical endodontic techniques is simple and easy to design and is a step forward toward mastering endodontic techniques.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.