Border Molding

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 (135-140F) 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

• Dont 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

• Dont 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
X-section through Mandibular ridge in 2nd Molar
region

• Lower border at or slightly below mylohyoid ridge
  but not deeply into the undercut below the ridge,
• Minimizes, abrasion and discomfort

Buccal
Mylohyoid Ridge
Attachments To Hyoid
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