1) Border molding involves manipulating tissues to duplicate the contour and size of the vestibule using thermoplastic materials, waxes, or impression materials. 2) A tray wax spacer remains in the tray during border molding to provide relief and is kept from melting in hot water. 3) Border molding requires softening materials, adapting the tray intraorally using functional movements, and ensuring a retentive yet comfortable peripheral seal.

1. Border Molding
Shaping borders of
impression tray
• Functional or manual
manipulation of tissues
• Duplicates contour & size
of vestibule

2. Border Molding
• Performed with
– Thermoplastic modeling
compound
– Waxes
– Impression materials

3. Tray Wax Spacer
• Remains in place during border
molding procedures

4. Custom Tray
• Comfortable
• 2-3 mm from vestibule
• Dry periphery of tray
(Compound will not
stick to tray otherwise)

5. Heating Compound
• Use Bunsen Burner
not Hanau Torch
• Warm until it starts
to droop
• Do not overheat – if
catches fire or boils,
it will not mold
properly

6. Compound Application
• Apply over
periphery of tray, in
a thickness just
slightly narrower
than the compound
stick

7. Re-soften After Application
• Flame with a hand
torch until all seams
or sharp contours
have disappeared
• Do not melt wax
spacer inside tray

8. Preventing Slumping
• Hold the tray upside down so
that compound droops toward
the depth of the vestibule

9. Tempering Compound
• Temper in a water bath (135-140°F)
for several seconds
– Prevent burning
– Hot water bath will keep compound
soft for an extended period

10. Wax Spacer
• Keep out of hot water bath
to prevent melting
– Difficult to replace tray
intraorally in the same
position
– Results in uneven border
molding

11. Prepare Patient
• Patient seated, head
against headrest, mouth
open & relaxed
• If patient “opens wide”,
commisures constrict,
limiting access

12. Inserting the Custom Tray
• Place intraorally by
rotating into place
– Mold by pulling on
the cheeks, lips
– Have patient make
functional
movements

13. After Removal
• Chill in cold water
• Trim excess over wax
spacer or external
material that is thicker
than 4-5 mm
– Clean debris from tray

14. Assessing Peripheral Role
• Proper thickness
• No overlap

15. Burnthrough
• Difficult to see (opaque)
• Relieve tray

16. After Trimming
• If border is sharp or
has seams, re-flame,
temper and readapt
intraorally
• Repeat until
periphery is
completed

17. Border Molding
• Don’t reduce border molding
prior to final impression if:
– Modern low viscosity materials
are used
– Sufficient relief (spacer + holes)

18. Maxilla - Seating the Tray
• Seat tray firmly in mid-palatal
area during border molding
procedures

19. Maxilla - Contouring
• Mold posterior
buccal by pulling
cheek down &
forward with
slight circular
movement

20. Functional Movements
• Patient moves mandible side to
side & opens wide
– Molds the retrozygomal area
– Allows for movement of coronoid
process
– Prevents impingement of
pterygomandibular raphe

21. Maxilla - Labial Frenum
• Pull lip outward & downward
– Do not pull to one side

22. Maxilla - Labial Frenum
• Labial frenum
should be narrow
• Buccal frena
usually broader,
“V-shaped”

23. Maxilla - Posterior Border
• Add compound across the top of
the tray (not at the edge)

24. Maxilla - Posterior Border
• Terminates at vibrating line and
hamular notches
• Mark with an indelible stick
– Insert tray & check visually

25. Evaluating Border Molding
• Relatively symmetrical

26. Evaluating Maxillary Border
Molding
• Retentive

27. Mandible
• More difficult
• Changing position of the floor
of the mouth

28. Posterior Buccal Areas
• Pull cheek upward while holding
tray in place
• Have patient suck cheeks inward
while holding tray in place

29. Retromolar Pad
• Should be covered (at least
partially) to provide a seal and
comfort to the patient

30. External Oblique Ridge
• Don’t extend past EOR
• Palpate cheek at angle
of the mandible
– Smooth transition
between mandible &
border - not palpable

31. Buccal Extension
• Look for fold in vestibule

32. Masseter Muscle
• Distal buccal extension
• Patient closes against force
• Activates the masseter, which
will displace the compound

33. Mandibular Frenal Attachments
• Labial frenum is narrow
– pull lip straight up,
– not as exaggerated as maxilla
• Buccal frena broad & “V-shaped”

34. Posterior Lingual Areas
• Have patient touch their tongue
to the corners of the mouth, to
the palate and stick their tongue
out of their mouth

35. Posterior Lingual Areas
• An “S” shaped lingual flange
commonly results in posterior
lingual area

36. Retromylohyoid Space
• Distolingual border can
extend
– Straight down from the
retromolar pads
– Anteriorly to varying
degrees
– Almost never angles
posteriorly from
retromolar pads

37. Posterior Lingual Areas
• Lower border at or
slightly below
mylohyoid ridge
but not deeply into
the undercut below
the ridge,
• Minimizes,
abrasion and
discomfort
Buccal
Attachments
To Hyoid
Mylohyoid
Ridge
X-section through
Mandibular ridge
in 2nd Molar region

38. Posterior Lingual Areas
• Denture should not lift with
normal tongue movements

39. Anterior Lingual
• Patient lifts tongue to palate, to
corners of mouth and sticks
tongue out
• Hold tray in place – denture
should not lift with normal
tongue movement