What is considered the most important local factor in the aetiology of periodontal disease?

Calculus is identified as the most important local factor in the aetiology of periodontal disease due to its role in the accumulation of plaque. When bacteria form biofilms on the teeth, they can lead to gingival inflammation and, if left untreated, progress to periodontal disease. Calculus, which is hardened plaque, provides a rough surface that enhances further plaque accumulation and may also contribute to the inability of patients to maintain optimal oral hygiene.

The presence of calculus is particularly significant because it acts as a reservoir for pathogens that trigger inflammatory responses in the surrounding gum tissue. Even with adequate brushing habits, once calculus forms, it requires professional dental cleaning to remove. Thus, the presence of calculus directly influences the severity and progression of periodontal disease, making it a critical factor in its aetiology. Other factors like occlusal trauma, brushing habits, and coarse food may contribute to oral health, but none have the same overarching impact on the formation and persistence of periodontal disease as calculus does.