The number of root canals varies from tooth to tooth, as follows: 1. The central incisors, lateral incisors, and cuspids are usually single root canals, that is, there is only one root canal. 2. The maxillary first premolar usually has two root canals. 3. The maxillary second premolar, and the mandibular premolar, are also usually one root canal. 4. The first and second molars are usually 3-4 root canals, and there are individual first and second molars that may have root canal variants, and the number of root canals may be up to six. 5. The number of root canals of wisdom teeth is uncertain because there are more variants of wisdom teeth and the shape and number of root canals will not be determined, and there are some individual patients with root canal variants.