Dental Which primary tooth is generally accepted as the first to erupt, and at about what mean age? A Maxillary central incisor, 8 to 12 months. B Maxillary central incisor, 7 to 9 months. C Mandibular central incisor, 7 to 9 months. D Mandibular central incisor, 8 to 10 months. 💡 Explanation Which primary tooth is generally accepted as the first to erupt, and at about what mean age? ✓ Correct Answer: C. Mandibular central incisor, 7 to 9 months.