What is a common symptom of gingivitis as caused by leukocytes?

In gingivitis, the primary symptom that stands out is the bleeding of the gingivae, which occurs due to inflammation of the gums. This inflammation is typically a response to the accumulation of plaque, leading to the activation of leukocytes (white blood cells) as part of the immune response. These leukocytes help combat the bacterial infection but contribute to swelling and irritation of the gum tissues. As a result of this inflammatory process, the blood vessels in the gingivae can become more permeable, leading to easy bleeding, especially during brushing or flossing.

The other symptoms mentioned, while they may be associated with oral health issues, are not specific indicators of gingivitis caused by leukocytes. Pain in the tooth typically suggests a deeper issue such as caries or pulpitis rather than gum inflammation. Dry mouth may lead to various dental problems but is not a hallmark symptom of gingivitis. Bad breath can occur due to periodontal disease but is more of a secondary symptom rather than a direct indication of inflammation in gingivitis. Therefore, the bleeding of the gingivae is the most characteristic and common symptom linked to gingivitis.