Hi Dear, Welcome to HCM. Understanding your concern. Thanks for query .There can be many reason why eruption of permanent teeth delayed like delayed in resorption in root of deciduous dentition due lingual position of erupting permanent dentition, unequal resorption or roots of deciduous,non formation of roots of permanent dentition due to trauma,ankylosis means union of root tip to the jaw bone,some medical condition (which is not in your case) and over crowding of permanent dentition. In case of lower or mandibular arch if deciduous dentition is present till eight year and permanent is also present then it is recommended to extract deciduous dentition. In case of upper arc or maxillary arch if the primary dentition is mobile and permanent is present the it is recommended to extract primary dentition even before eight year of age . Sometimes orthodontic appliances can be use to guide the eruption of permanents teeth . I would suggest you to visit regularly to explore the treatment options. Hope your concern has been resolved. Get Well Soon. Best Wishes, Dr. Harry Maheshwari