What is one reason for a negative vitality test in a lateral incisor?

A negative vitality test result indicates that the nerve within the tooth may not be functioning properly or is dead, which typically signifies pulp necrosis. This condition can occur due to various factors, such as deep decay, trauma, or untreated infections, leading to inflammation and eventual death of the pulp tissue. In the context of a lateral incisor, determining the health of the pulp is crucial for diagnosis and treatment planning, and a negative vitality test is a strong indicator of possible necrosis in that tooth.

While recent trauma can result in a temporary sensitivity or even pulp necrosis, it is not the only determining factor. Likewise, excessive occlusal forces might cause symptoms related to the periodontal tissues rather than the pulp directly. Class II caries may compromise tooth vitality, but it's more specific to the extent of decay and does not directly indicate necrosis without further assessment. Therefore, identifying pulp necrosis as a reason for a negative vitality test is essential in diagnostics and can lead to appropriate therapeutic interventions.