What is a potential adverse effect of excessive fluoride exposure during tooth development?

Excessive fluoride exposure during the critical period of tooth development can lead to a condition known as fluorosis. Fluorosis occurs when there is an overexposure to fluoride while the teeth are still forming, typically in children whose permanent teeth are developing beneath the gums. This condition often manifests as white spots, streaks, or even brown discoloration on the enamel of the teeth, which can affect both the aesthetic appearance and the surface quality of the teeth.

In contrast, tooth decay results from various factors including plaque accumulation and is not directly associated with fluoride overexposure. Enamel hypoplasia, which refers to a deficiency in the amount of enamel, is usually caused by other factors such as nutritional deficiencies or illness during development rather than fluoride. Gum recession is related to periodontal issues and does not stem from fluoride exposure. Therefore, fluorosis is the most relevant answer when considering the effects of excessive fluoride during the developmental stages of teeth.