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[Clinical observation of dental pulp and root changes of juvenile anterior permanent teeth after concussion and luxation].

OBJECTIVE
To observe the incidence of pulp necrosis and root resorption of the juvenile anterior permanent teeth with concussion and luxation injuries and analyze the relationship between the type of injury and form of root resorption.


METHODS
157 teeth of 79 patients were chosen from 201 patients with concussion and luxation treated with functional-bite-plate at the Department of Pedodontics, School of Stomatology, Beijing Medical University from 1984 to 1996.


RESULTS
High occurrence of pulp necrosis and root resorption were found in teeth with intrusion, and pulp necrosis occurred most within 3 months after the injury, while root resorption occurred during 3 weeks to 2 years. At the same time, surface resorption occurred mainly in the teeth with intrusion, extrusion and lateral luxation, and replacement resorption occurred only in intrusive teeth, however inflammatory resorption occurred in extrusive teeth whose pulp was infected.


CONCLUSION
Intrusion is the most severe type of tooth trauma.