boxing and pouring definitive impressions Flashcards
what is border molding
Shape the border area of an impression material bu functional or manual manipulation of soft tissue to duplicate the contour and size of the vestibule
what does border molding do
determines the extension of a prosthesis by using tissue function or manual manipulation of the peripheral limiting structures
where does border molding occur
at the junction of the attached and unattached mucosa
why must you do border molding
Borders of the denture must accommodate the physiologic movement of the frenums and muscles
what is the clearance needed for border molding
2-3 mm of clearance between edge of tray and depth of vestibule
how does one know when you are done border molding for the maxillary
when you pull the border molded tray by the handle and it has resistnace downward( obtained border seal)
how does one know that border molding is done
tray should remain stable when patient goes to lick
- if unstable, extensions are too long
what to do if mandibular extensions are too long
must reassess the tray
why do boxing
Provides superior hardness of master cast surface
provide land area to strengthen periphery of master cast
maintain thickness and contour of the border-molded periphery
Minimize cast trimming
what is the purpose of boxing
Define borders of final denture(creating seal)
controls dimensions of master cast
makes cast dense to resist pressure and temp of acrylic polymerizations
what happens if you lose border
result in inadequate retention and stability regardelss of impression, cast, or polishing denture
should land area be left on an impression
No
how far should the impression be inserted into the plaster-pumice mix
3-4mm below the borders of the max and mandibular definitive impression
how much circumferential space should be left for boxing around the impression for land ara
4-5mm
what is used to create the boxing area
50:50 mix of plaster and pumice with water to a good consisency
