Reline or Remake for a Flat-Ridge Mandibular Denture
A 68-year-old edentulous patient has worn a mandibular complete denture for four years. The ridge shows about 2 mm of resorption and is relatively flat. The patient reports that the denture rocks and that sore spots have developed at the mylohyoid ridge and retromolar pad. The dentist asks the lab to 'reline and reset the teeth' without a new impression. Examination of the denture shows the midline shifted 3 mm to the right, posterior teeth set on a flat plane with no curve of Spee, and a steep incisal guidance on the anterior teeth. The denture base is made of heat-cured acrylic and shows no cracks. The patient has a history of clenching and wears a maxillary complete denture with a moderate curve of Spee. The lab has the old casts but no current border-molded impression. The dentist wants the case returned in four days. The lab must decide whether a reline, a reset, or a remake is appropriate, and how to correct the occlusion.
1. Identify the setup errors that could cause the denture to rock and produce sore spots.
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Errors: The 3 mm midline shift and the flat posterior plane with no curve of Spee would make the denture look and function asymmetrically. A steep incisal guidance on a flat ridge increases tipping forces during protrusion. The denture is also four years old on a 2 mm resorbed ridge, so the base no longer fits. Those factors concentrate pressure at the mylohyoid ridge and retromolar pad and cause rocking. A reline alone cannot correct the tooth positions or the occlusal scheme.
2. What should the lab recommend: reline, reset, or remake? Justify your recommendation.
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Recommendation: Do not rely on a chairside reline as the definitive treatment. The tooth setup is wrong and the ridge is resorbed, so a remake is the safer choice; at minimum, a laboratory remount and reset of the posterior teeth in a stable base would be needed, but the four-year-old acrylic and 2 mm resorption make that less predictable. For the remake, set the teeth in the neutral zone, correct the midline, establish a curve of Spee, and use a lingualized or monoplane occlusal scheme suitable for a flat ridge. Reduce the incisal guidance and verify balanced contacts in centric and excursions. A new border-molded impression is required; the old casts are not adequate.
3. How would you verify balanced occlusion in the laboratory before returning the case?
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Verification: Mount the new dentures on a semi-adjustable articulator with a facebow or a verified mounting. Check centric occlusion for simultaneous bilateral posterior contacts and no anterior slide. Check protrusive and lateral excursions for balanced contacts; with a flat ridge, a lingualized or monoplane scheme should show contact on the working side and no balancing interference. Mark the intaglio for pressure areas and relieve the mylohyoid ridge and retromolar pad only after the occlusion is balanced, not before.