Which pattern is angular and more severe on the affected tooth?

• A. Horizontal bone loss
• B. Generalized horizontal, localized vertical
• C. Vertical bone loss
• D. Furcation involvement

Answer: (C)

Vertical bone loss creates infrabony, or angular, defects that are localized to one tooth or a small group, making the loss appear more severe on the affected tooth. In this pattern, bone resorption occurs beneath the crest, forming a trench-like defect with an acute angle between the remaining bone walls. Horizontal bone loss, by contrast, encircles the tooth evenly and maintains a more uniform crest. Furcation involvement involves the area where a multirooted tooth splits, and while it can accompany vertical defects, the defining feature described here is the angular, localized nature of vertical bone loss.