Which of these is a common sign of gingivitis in children?

Bleeding gums is considered a common sign of gingivitis in children because it indicates inflammation and irritation of the gum tissue, which occurs due to plaque buildup along the gumline. When gums become inflamed, they can bleed easily during brushing or flossing. This condition is often reversible with improved oral hygiene practices.

The other options, while they can be associated with various dental or oral health issues, are not typical indicators of gingivitis. White patches on gums may suggest a fungal infection or other conditions rather than gingivitis itself. TMJ dysfunction relates to jaw joint issues and is not a sign of gingival inflammation. Halitosis, or bad breath, can arise from numerous dental or systemic issues but is not specifically a hallmark of gingivitis. Therefore, bleeding gums clearly illustrates the presence of gingivitis and aligns with the symptoms typically observed in this condition.