Which area in the oral cavity is least effectively cleaned by manual toothbrushing?

Interdental areas are often the least effectively cleaned by manual tooth brushing due to their specific anatomical features. These spaces between the teeth can trap plaque and food particles, making it difficult for a toothbrush to reach them adequately. While a toothbrush can clean the surfaces of the teeth effectively, it does not have the capacity to get between the teeth where plaque accumulates.

To ensure proper oral hygiene, it is generally recommended to use additional cleaning tools, such as dental floss or interdental brushes, specifically designed to remove debris and plaque from these tight spaces. Other areas in the oral cavity, such as the gingival crevice, lingual tooth surface, and occlusal fissure, may be more accessible to a toothbrush and can be maintained effectively with good brushing techniques.