LMP 102

Different Pouring Methods 

• Double-pour method
  • The anatomic portion of the model is poured first; then a second mix of plaster or stone is used to prepare the art portion.
• Box-and-pour method
  • The impression is surrounded with a “box” made of wax and poured as one unit.
• Inverted-pour method
  • One large batch of plaster or stone is mixed and both portions of the model are poured in a single step. 

Examples of Pouring Methods

Trimming and Finishing of Dental Models

• Prepare the model
  • Soak it in water for 5 minutes. 
• Trimming the maxillary model 
  • Trim the base.
  • Trim the posterior area.
  • Trim the sides.
  • Trim the heel cuts.
  • Trim the angled portion from canine to canine.

• Trimming the mandibular model
  • Trim the posterior portion of the mandibular model until it is even with the maxillary model.
  • Trim the base.
  • Trim the lateral cuts to match the maxillary lateral cuts.
  • Trim the back and heel cuts.
  • Trim from canine to canine in a rounded form.

• Finishing the model 
  • Mix a slurry of gypsum and fill in any voids.
• Polishing a plaster model 
  • Soak the model in a soapy solution for 24 hours.
  • Dry the model and then polish it with a soft cloth.

Dental Waxes

• Boxing wax 
  • Soft, pliable wax with a smooth, shiny appearance. 
  • Supplied in long narrow strips measuring 1 to 1½ inches wide and 12 to 18 inches long. 
  • Used to form a wall or box around a preliminary impression when pouring.

• Utility wax 
  • This wax is supplied in various forms, depending on its use.
  • It is composed of beeswax, petrolatum, and other soft waxes.
  • Uses 
    • Extend the borders of an impression tray
    • Cover brackets in orthodontic treatment 

• Sticky wax
  • Supplied in sticks or blocks
  • Main ingredients are beeswax and rosin 
  • Very brittle but becomes very tacky when heated
  • Useful in the creation of a wax pattern or joining of acrylic resin

• Inlay casting wax 
  • Hard, brittle wax made from paraffin wax, carnauba wax, resin, and beeswax
  • Used to create a pattern of the indirect restoration on a model
  • Classified according to flow:
    • Type A: hard-inlay wax
    • Type B: medium-inlay wax
    • Type C: soft-inlay wax

• Casting wax 
  • Made up of paraffin, ceresin, beeswax, and resins 
  • Supplied in sheets of various thicknesses 
  • Used for single-tooth indirect restorations, fixed bridges, and casting of metal portions of a partial denture 

• Baseplate wax
  • Made of paraffin or ceresin with beeswax and carnauba wax 
  • Hard and brittle at room temperature
  • Supplied in sheets
  • Three types
    • Type I: softer wax used for
      denture construction 
    • Type II: medium-hardness wax used
      in moderate climates
    • Type III: harder wax for use in
      tropical climates

• Bite-registration waxes
  • These waxes are soft and very similar to casting waxes.
  • Bite-registration wax softens under warm water.
  • The patient is instructed to bite down, leaving an imprint of the teeth in the wax.

Utility wax is clear/white or red.

It is most often supplied in long ropes.

It is easy to apply and remove.

Inlay casting wax is mostly used by the dental laboratory technician.

For what processes are the different classifications of inlay wax used?

For what processes is casting wax used?

Baseplate wax is pink. What else can baseplate wax be used for? (Bite registration.)

Bite-registration waxes are supplied in wafer form.

What is the purpose of a bite registration?