Which of the following specialties focuses on the treatment of diseases surrounding the tissues of the teeth?

The specialty that concentrates on the treatment of diseases affecting the tissues surrounding the teeth is periodontics. This field deals with the prevention, diagnosis, and treatment of periodontal diseases, which include conditions that affect the gums, ligaments, and bone supporting the teeth. Periodontists are trained to manage various issues such as gingivitis and periodontitis, and they perform procedures that can range from non-surgical therapies to surgical interventions, aimed at maintaining the health of the foundational structures of the teeth.

In contrast, orthodontics focuses on correcting teeth and jaw alignment, endodontics is concerned with diseases of the dental pulp and root canals, and prosthodontics involves restoring and replacing missing teeth with crowns, bridges, or dentures. Each of these specialties has a distinct focus, but periodontics specifically targets the health of the supportive structures around the teeth, making it the correct answer for this question.