Note that the quantity of plaster is approximate; your plaster mix should have a similar consistency to the mix shown in the video.
Remember that you need to let your plaster models dry for at least 45 minutes before you attempt to remove them from the moulds. Your dental models should look something like the plaster model shown in Figure 1.2.
Figure 1.2: Close-up of a dental model
Step 3 Set the models aside, as you will need them in Activity 2.
Clean up and put away your materials, making sure they are in good condition. Tidy your work area.
Now that you have made your dental models, you are ready to practise carving missing teeth and filling cavities.
W ax teeth and restorations Using the two plaster dental models you made in the previous activity, you will now test your manual dexterity by carving missing teeth and filling in cavities on several teeth using a wax stick.
This exercise will help you to better understand the type of work that dentists and dental hygienists do when they repair decayed teeth. It will also give you the opportunity to discover the exact morphology (shape) of adult teeth like yours.
In order for this exercise to be effective, we recommend that you carve at least one tooth and perform one restoration (fill a cavity).10 The Ivorine Dentoform® model available in class is a good reference tool. You can also consult Appendix A.
What you will need to complete this activity:
You will start by carving an incisor (see Figure 2.1).
Figure 2.1: Permanent teeth of right half of lower dental arch
Step 1 Visit the POP Links website at http://liensppo.qc.ca and click on “Dentistry.” Scroll down to the “Videos” section. Watch the “Making a Plaster Dental Model” video clip, which explains how to carve teeth and perform restorations. (Start the video at 3:52 minutes; if you have not yet removed the plaster dental models from the moulds, start watching the video at 3:00 minutes and do that first.)
WARNING! Although the video clip shows a gas burner being used to heat up the tips of the carving instruments and soften the wax, you will be using a candle for this purpose. Please be careful as you work with the hot instruments and never leave a burning candle unattended.
Step 2 Using the Ivorine Dentoform® model, study the shape of the tooth you need to reproduce so you can recreate it exactly. Use the three carving instruments provided to do so.
Step 3 Once the tooth you have carved resembles the shape of a real tooth, you can improve its lustre by polishing it with the piece of nylon stocking.
Step 4 If you do not have time to do more, clean up and put away your materials, making sure they are in good condition. Tidy your work area.
Exercise 2 (optional)
If you enjoyed Exercise 1 and want to further challenge yourself, carve a second tooth, such as a molar (see figures 2.2 and 2.3). Repeat the steps in Exercise 1, as required.
Figures 2.2 and 2.3: Dental models with carved teeth (molars are circled)
Next, fill a molar. Again, study the shape of the tooth you need to reproduce using the Ivorine Dentoform® model, so you can recreate it exactly. Use the three carving instruments provided to do so.
When a dentist or dental hygienist fills a cavity, the exact shape of the tooth must be reproduced as accurately as possible (see Figure 2.4).
Figure 2.4: Dental model with fillings in a molar (circled) and premolar