What is the primary purpose of conducting a vitality test on teeth?

The primary purpose of conducting a vitality test on teeth is to determine the need for root canal treatment. This test assesses whether the tooth's pulp is still alive and functioning, which is critical when diagnosing the health of the tooth. During a vitality test, stimuli such as cold or electrical impulses are applied to the tooth to evaluate nerve responses. A positive response indicates that the pulp is likely healthy, while a lack of response can suggest pulp necrosis or irreversible pulpitis, often necessitating endodontic treatment.

In contrast, tests for periodontal health, evaluations for extraction, or identifying caries do not primarily rely on assessing the vitality of the dental pulp. Each of these areas involves different diagnostic approaches and assessments focused on conditions affecting the supportive structures of the teeth, structural integrity, or decay, rather than the tooth's nerve health. Vitality tests specifically target the health of the pulpal tissue, making option A the correct choice for this question.