82 - Model cast RPD technology – basic steps: and 83 - . Immediate RPD technology:

what does rpd usually consist of?

e usually consists of replacement teeth (Artificial Teeth) attached to a pink or gum colored plastic base (Denture Base), which is connected by metal framework (clasps) that holds the denture in place in the mouth.

how long is denture development process?

three to six weeks and several appointments

steps to rpd construction

1. Impressions:

- These are negative replica of patients hard and soft tissues of oral cavity, usually taken using alginate (Impression Material) in a special tray.

2. Model Preparation After Impression By Cast or Die materials.

3. Use a dental surveyor:- to determine heights of contour with a common path of insertion.

4. Framework:

- Adaptating, and determining the positioning of clasps.

5. Waxing and Setup of artificial teeth.

6. Flasking: - The process of investing the cast and a waxed denture in a flask to make a sectional mould used to form the acrylic resin denture base:

• Mix the gypsum in proper water/powder ratio.

• The lower part of the flask is filled first. Put the model in it (max 1cm over the edge of the flask - without shaft).

• Soap water, isodent and other for isolation after hardening.

• Put the upper part and fill it with plaster.

• After hardening – put the flask in boiling water for 5 minutes.

• After that open it and remove the plasticized base plate and the wax. • Isolation.

7. Polymerization:

• Mix the acrylic resin (polymer + monomer).

• Stages of polymerization:

❖ Wet sand phase

❖ Sticky ("threads") phase

❖ Plastic ("working") phase

❖ Elastic ("gummy") phase

• Put the acrylic resin in the empty space, close the flask and press it.

• High temperature polymerization cycle:

❖ Long: put the flask in room temperature water, heat it for 30 minutes while the temperature rises till 60 degrees Celsius, on 60 degrees Celsius – for 1 hour, heat it for 30 minutes till 100 degrees Celsius, on 100 degrees Celsius – 30 minutes and slow cooling (2 and a half hours).

❖ Short: for 30 minutes after water starts to boil. (No more than 100 degrees Celsius, because the monomer evaporates on 100.3 degrees Celsius!)

8. After cooling:- remove the denture from gypsum.

9. Cleaning and polishing.

what is immediate removable partial denture?

any removable dental prosthesis fabricated for the placement immediately following the removal of the natural teeth