Dental impressions have always piqued my curiosity. It’s fascinating that a patient’s oral structures can be created with dental impression and dental plaster to fabricate a dental cast to allow dental work to be performed without the patient being there physically. In this homework assignment, I explored this technique by molding and casting my fingers.

Creating the Mold

The first step was to create a mold. To do this, I mixed alginate to water in a 1:4 ratio. Using a silicone cup, I measured out 200 grams of water and approximately 50 grams of alginate and mixed them together using a popsicle stick. Rachel recommended that I mix the two ingredients quickly to avoid them from hardening and to remove any clots of unmixed alginate from the bottom of the cup. After about 4-5 minutes of mixing, I placed my pointy finger straight into the mold for 5 minutes. After 5 minutes, as I gently wiggled my finger, I could feel the mold harden and hold the place for my finger. Seeing this, I took my finger out and prepared for the next phase: plastering.

I think it was really cool to see my fingerprint engraved within the mold. I could notice the small details from my finger.

Plaster Phase

Subsequently, I measured out Plaster of Paris and water in a 2:1 ratio and mixed them together. Rachel helped me with getting the consistency right. She pointed out that I may need to add more water/alginate depending on the consistency as I mixed. After getting a semi-solid/slurry consistency, I added the mixture into the mold. Then I quickly placed a screw at a 1 cm depth into the mold and used tape to hold it in place. While the plaster takes about 5-10 minutes to dry and harden, I waited for 1 hour before taking it out.

Demolding Time!

The demolding phase was kind of scary. I was excited to see my casted finger, but I was scared to pull the cast out of the mold in fear that it may break. Luckily, I was able to remove my cast nicely and I was in awe at how nice it looked. I could see that my finger print and wrinkles appeared nicely on the cast as well.

After casting my finger, I repeated the plaster phase to create an identical cast.

Post Process

In the next phase, I spray painted my fingers using a clear coat to give it a nice strong finish. Spray painting and drying took a total of 6 minutes.

Here is the final product!

in Retrospect

In my final product, I noticed small air bubbles on the top region. I think this may have come from me pouring in the plaster in too quickly. If I were to do this again, I would be more careful in this step. In retrospect, casting and molding was both a fun and insightful experience. I was amazed at how efficient it can be to create multiple, identical pieces once the mold is developed.

Casting and Molding Cost Analysis

Below, I have included a breakdown of the cost estimate for my molding and casting.

Material Cost:

• Alginate [1]: $8.99/454 grams * 200 grams = $3.960
• Plaster of Paris [2]: $9.69/lb *1 = $9.69
• Popsicle Stick [3] = $4.99/100 sticks * 1 = $0.0499
• 5 inch Screw [4] = $8.29/50 screws * 1 = $0.1658
• Silicone Cups [5] = $9.99/10 pcs * 1 = $9.99
• Spray paint [6]: $9.98/bottle * 1 = $9.98

Overall Material Cost: $33.8537

Labor:

Overall Labor Cost [7]: $7.25/hr X 2 hours = $14.5

 

Total Cost: $48.3357

[1] https://www.amazon.com/Create-Alginate-Molding-Powder-Casting/dp/B007PULSRM/ref=sr_1_1_sspa?keywords=alginate&qid=1668370602&s=arts-crafts&sr=1-1-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&th=1

[2] https://www.amazon.com/SELECTION-1lb-Plaster-of-Paris/dp/B075RZZPXX/ref=sr_1_2_sspa?crid=2LS8UMOV5HXQY&keywords=plaster+of+paris&qid=1668370707&s=arts-crafts&sprefix=plaster+of+pari%2Carts-crafts%2C138&sr=1-2-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&psc=1

[3] https://www.amazon.com/Karlash-Jumbo-craft-sticks-length/dp/B072MQTWGH/ref=sr_1_3_sspa?keywords=popsicle+stick&qid=1668370800&s=arts-crafts&sprefix=popsc%2Carts-crafts%2C134&sr=1-3-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&psc=1&smid=A2XNW7021L3K1O

[4] https://www.amazon.com/Hillman-42180-Crafter-2-Inch-50-Piece/dp/B0052EBZTO/ref=sr_1_2?content-id=amzn1.sym.918a99dd-4826-4c0a-be33-a6705d69c4cf%3Aamzn1.sym.918a99dd-4826-4c0a-be33-a6705d69c4cf&keywords=Screws&pd_rd_r=7be46d23-5a33-4a81-8316-9ae929567a90&pd_rd_w=Ezi9l&pd_rd_wg=Grrnc&pf_rd_p=918a99dd-4826-4c0a-be33-a6705d69c4cf&pf_rd_r=73HRG4PYE6P55EAD0V2W&pid=gXy9xUb&qid=1668370880&refinements=p_n_feature_twenty-eight_browse-bin%3A19043709011&s=industrial&sr=1-2

[5] https://www.amazon.com/Silicone-Measuring-Non-Stick-Precise-Jewelry/dp/B08S3CV28C/ref=sr_1_2_sspa?crid=14IISXADL9F0K&keywords=silicone+measuring+cups&qid=1668370955&s=industrial&sprefix=silicone+measuring+cups%2Cindustrial%2C93&sr=1-2-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&psc=1

[6] https://www.amazon.com/Rust-Oleum-7251830-Stops-Metallic-Cobalt/dp/B000LNWCKM/ref=sr_1_2?keywords=metallic+blue+spray+paint&qid=1665387592&qu=eyJxc2MiOiI0Ljk2IiwicXNhIjoiNC41NCIsInFzcCI6IjQuMzIifQ%3D%3D&sr=8-2

[7] https://www.minimum-wage.org/texas#:~:text=The%20Texas%20minimum%20wage%20was,Federal%20Minimum%20Wage%20by%20reference