Over-extension in depth
Slow rise of lower denture when mouth half open, line of inflammation at reflection of sulcal tissues; ulceration in sulcal region.
Deep post dam on upper base may cause pain, ulceration
If buccal to tuberosities, denture displaces on mouth opening, or cheek soreness occurs. Thickened lingual flange enables tongue to lift denture; thick upper and lower labial flanges may produce displacement during muscle activity
Slightly under-extend denture flange and accurately mould softened tracing compound. Check borders of record rims and trial dentures at the appropriate stages. Deep post dam to be cautiously reduced and denture worn sparingly until inflammation clears
Overextension in width
Cheeks appear plumped out. In lower, the buccal flange may be palpated lateral to external oblique ridge
Reduce over-extension. Use disclosing material to determine what is excessive
Poor fit to supporting tissue
Recoil of displaced tissue lifts denture
Poor/inappropriate impression technique especially in posterior lingual pouch area
Reline if all other design parameters satisfactory, otherwise remake. Ensure denture is removed from mouth 90 mins prior to impression
Denture not in optimal space
Molars on lower denture lingual to ridge, optimum triangular shape of dentures absent Posterior occlusal table too broad, causing tongue trapping
Thick lingual flanges encroaching on tongue space, causing lifting.
Excess lip pressure to lower anterior aspect - teeth anterior to ridge, thick periphery Excess pressure from upper lip to upper denture arising from teeth too labially sited to acute naso-labial angle; or failure to adequately seat denture during relining impression procedure
Remove lingual cusps and lingual surface from relevant area, repolish.
If triangular form not restored, reset teeth or remake dentures
Narrow posterior teeth and/or remove most distal teeth from dentures. Reshape lingual polished surface
Thin lower labial flange, ensure optimal extension to retromolar pads to resist displacement, reset anterior teeth if necessary
Usually requires remaking denture