Final answer:
Neutrophils are the primary cells that migrate in large numbers to the gingival sulcus in response to the accumulation of plaque, playing a crucial role in the innate immune response against bacterial invasion.
Step-by-step explanation:
Immune Cells Migrating to the Gingival Sulcus
The accumulation of plaque in the gingival sulcus prompts an immune response where neutrophils migrate into the area in the largest numbers. These cells are a vital part of the innate immune system and act as the first line of defense against bacterial infections. Neutrophils are one of the types of leukocytes, which can quickly respond to bacterial invasions by phagocytosing the invaders, thus playing a crucial role in protecting the oral cavity from infections that can arise due to plaque buildup.
Other cells such as epithelial cells, fibroblasts, and lymphocytes do play a role in the immune response and tissue repair but are not the primary cells that migrate to the gingival sulcus in response to plaque. Instead, fibroblasts are more involved in the repair of connective tissue, while lymphocytes are more associated with the adaptive immune response, which is typically slower to respond than the innate immune response in which neutrophils are involved.