Which statement about residual ridge resorption is TRUE?

Correct answer: D. The mandible resorbs downward and OUTWARD, becoming wider

• A. Incorrect — the mandible resorbs roughly four times faster than the maxilla.
• B. Reversed — the maxilla resorbs inward and becomes narrower, not wider.
• C. Reversed — this describes the maxillary, not mandibular, pattern.
• D. Correct. Because of the direction of the labial/buccal plates, the MANDIBLE resorbs downward and OUTWARD — the arch becomes progressively WIDER. The MAXILLA resorbs upward and INWARD, becoming NARROWER. The combined effect over time is the pseudo–Class III appearance of the long-term edentulous patient. Mandibular resorption also proceeds about FOUR TIMES faster than maxillary.