Impacted or intruded teeth result when a tooth is forced deeper into the alveolar socket or surrounding tissues as a result of trauma. The tooth appears shorter than its contralateral mirror. An impacted tooth may be partially visible or completely hidden by the gingiva and buried in the alveolar process. Completely impacted teeth may erroneously be considered avulsed until a radiograph demonstrates the intruded position. The apex of a completely impacted permanent central incisor may be driven through the alveolar bone into the floor of the nares, causing epistaxis. Associated injuries may include alveolar fractures, dental crown or root fractures, and oral mucosal or gingival lacerations. Pulp necrosis occurs in 15% to 50% of cases.
Management and Disposition
Impacted primary teeth usually re-erupt and reposition spontaneously within 1 to 3 months. Any intruded primary tooth whose apex is displaced toward or impacts on the follicle of its permanent successor requires dental follow-up for extraction and monitoring clinically and radiographically for 1 year. Permanent teeth do not re-erupt. Surgical reduction is indicated to prevent complications such as external root resorption and loss of supporting bone. Orthodontic repositioning and splinting are generally carried out over 3 to 4 weeks. Good oral hygiene should be maintained by using chlorhexidine 0.12% topically twice a day for a week.
An undiagnosed impacted tooth is predisposed to infection and may have a poor cosmetic result.
The maxillary incisors are the most commonly impacted teeth.
Tooth Intrusion. This impaction injury with multiple anterior maxillary tooth involvement shows various degrees of tooth impaction. Also note the complete absence of a central incisor. This may indicate a complete intrusion into the alveolar socket or an avulsion of the tooth. Radiographic studies are required when a tooth’s location is in question. (Photo contributor: James F. Steiner, DDS.)