Which of the following is a sign of periodontal disease?

Gum swelling and bleeding during brushing are significant indicators of periodontal disease. When bacteria accumulate in plaque and tartar, they can irritate the gum tissue, leading to inflammation known as gingivitis. This inflammation is often manifested as swollen gums, which may bleed during routine activities such as brushing and flossing. Consistent signs like these indicate that the gums are not healthy and may progress to more severe conditions like periodontitis if left untreated.

In contrast, tooth whitening is related to cosmetic dental procedures rather than periodontal health. Fresh breath suggests effective oral hygiene and healthy gums, as periodontal disease often results in bad breath due to the presence of bacteria and infection. Increased tooth sensitivity can occur for various reasons, including enamel erosion or issues with the teeth themselves, but it is not a direct sign of periodontal disease. Therefore, the presence of gum swelling and bleeding during brushing is the most telling sign of periodontal disease among the options presented.