- The process of post-extraction remodeling of the alveolar ridge involves several characteristic changes due to bone resorption and soft tissue healing.
- After a tooth is extracted, the alveolar bone loses its primary functional stimulus, which leads to gradual resorption and remodeling of the ridge.

- The most notable change seen in the residual alveolar ridge is a gradual decrease in height.
- This occurs because the bone that once supported the tooth undergoes resorption, especially at the crestal portion, resulting in a reduction of vertical dimension over time.
- In addition to the height reduction, there is also often a decrease in width, but the height loss is more significant and consistent.

- Option 1: Gradual decrease in height is correct because the residual ridge progressively loses vertical bone height after extraction.
- Option 2: Increase in width with stable height is incorrect; instead, there is usually a decrease in both height and width.
- Option 3: Immediate thickening of the ridge is not typical; the ridge tends to resorb rather than thicken.
- Option 4: No significant morphological changes is incorrect, as remodeling always results in changes in ridge shape and size.

Hence, the characteristic change is best described as a gradual reduction in alveolar ridge height following tooth extraction.

Reference: Contemporary Oral and Maxillofacial Surgery, 7th Edition, Chapter 5: Alveolar Ridge Preservation, Page 150-155