Border Molding
Border Molding
Border Molding means shaping borders of impression tray

- Functional or manual manipulation of tissues
- Duplicates contour & size of vestibule
- Performed with
- Thermoplastic modeling compound
- Waxes
- Impression materials
Tray Wax Spacer


- Remains in place during border molding procedures
Custom Tray
- Comfortable
- 2-3 mm from vestibule
- Dry periphery of tray (Compound will not stick to tray otherwise)
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
Compound Application
- Apply over periphery of tray, in a thickness just slightly narrower than the compound stick
Re-soften After Application


- Flame with a hand torch until all seams or sharp contours have disappeared
- Do not melt wax spacer inside tray
Preventing Slumping
- Hold the tray upside down so that compound droops toward the depth of the vestibule
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
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
Prepare Patient
- Patient seated, head against headrest, mouth open & relaxed
- If patient “opens wide”, commisures constrict, limiting access
Inserting the Custom Tray


- Place intraorally by rotating into place
- Mold by pulling on the cheeks, lips
- Have patient make functional movements
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
Assessing Peripheral Role

- Proper thickness
- No overlap
Burnthrough


- Difficult to see (opaque)
- Relieve tray
After Trimming
- If border is sharp or has seams, re-flame, temper and readapt intraorally
- Repeat until periphery is completed
Border Molding
- Don’t reduce border molding prior to final impression if:
– Modern low viscosity materials are used
– Sufficient relief (spacer + holes)
Maxilla – Seating the Tray


- Seat tray firmly in mid-palatal area during border molding procedures
Maxilla – Contouring
- Mold posterior buccal by pulling cheek down & forward with slight circular movement
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
Maxilla – Labial Frenum


- Pull lip outward & downward
– Do not pull to one side
- Labial frenum should be narrow
- Buccal frena usually broader, “V-shaped”
Maxilla – Posterior Border
- Add compound across the top of the tray (not at the edge)
- Terminates at vibrating line and hamular notches
- Mark with an indelible stick
– Insert tray & check visually
Evaluating Border Molding
- Relatively symmetrical
Evaluating Maxillary Border Molding
- Retentive
Mandible
- More difficult
- Changing position of the floor of the mouth
Posterior Buccal Areas
- Pull cheek upward while holding tray in place
- Have patient suck cheeks inward while holding tray in place
Retromolar Pad
- Should be covered (at least partially) to provide a seal and comfort to the patient
External Oblique Ridge
- Don’t extend past EOR
- Palpate cheek at angle of the mandible
– Smooth transition between mandible & border – not palpable
Buccal Extension
- Look for fold in vestibule


Masseter Muscle
- Distal buccal extension
- Patient closes against force
- Activates the masseter, which will displace the compound
Mandibular Frenal Attachments
- Labial frenum is narrow
– pull lip straight up,
– not as exaggerated as maxilla
- Buccal frena broad & “V-shaped”
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
- An “S” shaped lingual flange commonly results in posterior lingual area
Retromylohyoid Space
- Distolingual border can extend
– Straight down from the retromolar pads
– Anteriorly to varying degrees
– Almost never angles posteriorly from retromolar pads
Posterior Lingual Areas
- Lower border at or slightly below mylohyoid ridge but not deeply into the undercut below the ridge,
- Minimizes, abrasion and discomfort
- Denture should not lift with normal tongue movements
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
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