Which of the following conditions can lead to gingivitis?

Gingivitis is primarily caused by the accumulation of plaque on the teeth, which occurs when oral hygiene practices are inadequate. Poor oral hygiene leads to the buildup of plaque, a sticky film of bacteria that irritates the gums. When plaque is not effectively removed through daily brushing and flossing, it hardens into tartar, further exacerbating gum irritation and inflammation. This inflammatory response is the hallmark of gingivitis, characterized by swollen, red, and bleeding gums.

In contrast, good oral hygiene, regular dental check-ups, and a high-fiber diet contribute positively to oral health by reducing plaque accumulation, promoting regular cleaning of the teeth and gums, and supporting overall gum health, respectively. Therefore, poor oral hygiene is a significant risk factor for developing gingivitis.