Border molding Flashcards
what is Border molding
Shaping of an impression material by functional or manual manipulation of the tissue to duplicate/record the contours, height, width, and depth of the vestibule
what is the objective of border molding
determine contours
height
width of border of the complete denture
why is border molding needed
To gain maximum bearing area of denture
correct clearence from frenum
correct clearange of muscle and membranous attachments
obtain peripheryl seal for max stability and retention of final denture
what happens if border molding material extends onto the wax spacers
removal of wax prior to impression disrupts the border molding
how long should patients remove dentures before impression appointment
remove denture 24 hours prior to appointment
why should a patient remove dentures 24 hours prior to treatment
allows tissue recovery and keratinization of the edentulous muccosa
why is PVS good to use
Easy to mix and dispense
why does PVS make good impression
good dimensional stability and acuracy (week)
what makes easier to remove
Excellend eleastic recovery
what is the stiffest elastomeric impression material
Polyether Rubber
what makes Polyether rubber good for impression
Optimal recording of the functional periphery sealr
Dimensional stability (week)
hydrophylic
excelent soft tissue detail
why is polyether rubber bad
Bitter taste
how much wax is removed from the inside of a tray to allow for border molding
2mm
what shape of joint does border molding make with the tray
U shaped
how much clearance between the tray and vestibule should there be
2mm
what is the key to a succesful impression
Borders
what is the prerequisite to successful impression making
knowing muscles and structures produce the border
- how to activate said muscles
what are the border action for a maxillary impression
- ask patient to create suction around a finger and the impression tray handle
- ask patient to create suction around a finger and pucker lips to produce a maximal smile line
- ask patient to open mouth wide and move mandible side to side and stretch pterygomandibular raphe allowing the coronoid processes to shape the impression
- pinch nostrils closed and ask patient to blow air through nose while holding down the tongue/ have patient say aah or caugh
what does creating suction/ puckering lips help to border mold
Labial and bucal frena
Labial and buccal vestibule
what does moving the mandible side to side help create for border molding
the coronoid processes
Pterygomandibular raphe
what should you do if moving mandible side to side creates differences in the right and the left of the border molding
repeat to check if this is acurate
what happens if you don’t border mold for the coronoid process
causes pain and dislodging of denture
what does blowing air out of the nose while it is pinched off show
Hard-soft palate junction
what does saying ahh allow you to locate
Vibrating line
what is the importance of doing both saying of AHh and air blowing
Identify the area between the vibrating line and the hard palate soft palate junction
what are the key actions for mandibular border molding
- ask patient to create suction around a finer and impression tray handle
- pucker or pooch lips to create a maximal smile line
- pronounce the word christmas, letter Q and U and pull lower lip and cheek superioly over the impression tray
- place finger on the top of each side of the impression tray and ask the patient to close mandible against resistance using one second intervals of applied force
- ask patient to raise their tongue to the roof of the mouth, then anterior to vermilion border, then corners of mouth, and then swollow if possible
how far back should a mandibular custom tray go
all the way back to the retromolar pads and beccal shelves
what is done to the tray after border molding
Remove the wax spacer
how is material to be loaded into a custom tray
2-3mm thickness
Loaded quickly to avoid viscosity increase
avoid bubbles
bring material over peripheries
what happens if you record tissue in a dispaced location
the pressure limits normal blood flow, depriving tissue of normal blood supply
- resorption of bone occurs
how should a completed maxillary impression look
smooth with well defined peripheries adequate flange extensions Soft tissue detail maximum extension even pressure distribution intimate tissue contact
how should acompleted mandibular impression look
Smooth, well defined periphery
Maximum extension
even pressure distribution
intimate tissue contact
why do we use heavy body for border molding
Normal impression material would be too runny and wouldn’t allow for 4-5mm of border molding
what is elastic recovery
how well a material bounces back after being deformed
why does flexibility of impression material matte
helps with pulling out of the impression, when undercuts may be present
