Which statement best describes horizontal bone loss?

• A. Even/uniform apical migration of alveolar crest
• B. Angular bone loss along the root
• C. The anatomical area of a multi-rooted tooth where the roots divide from the main tooth trunk
• D. Length of radiographic crown divided by length of radiographic root

Answer: (A)

Horizontal bone loss is shown by an even, uniform recession of the alveolar crest toward the root apex around the tooth. This pattern means the bone around the tooth drops apically in a parallel fashion, so the crestal level moves down evenly on all sides and radiographs show a generalized, flat crest rather than a sharp angular defect.

This differs from vertical (angular) bone loss, where bone recedes in an angular manner along the root, creating a more pronounced interproximal defect and deeper pockets in specific areas. The furcation area is simply where multi-rooted teeth split, not a description of a bone loss pattern. The crown-to-root length ratio is a measurement of tooth support, not how bone loss is distributed around the tooth.