I have a small nodule on my gum. how can the dentist tell if you need a root canal?

Root canals: The dental examination will include x-ray, visual exam, and pulp vitality tests.. These will determine if the pulp and nerve is infected or healthy and if the nodule is tooth related or something else. A root canal is needed if the pulp is infected or necrotic.

A clinical: And radiographic evaluation are necessary to determine if endodontics treatment is indicated. Patients chief complaint is also useful in this evaluation. Hope this helps.

Many reasons: Can be many reasons for "nodule" such as tooth abscess, gum abscess, benign tumor, cancer, fibromyalgia, papilloma, etc. Dentist will do physical exam and may take x-rays or do biopsy to determine cause and treatment. Please call your dentist now for an appointment.