Get access

The dental trauma internet calculator


Correspondence to: Thomas A. Gerds, Department of Biostatistics, University of Copenhagen, Øster Farimagsgade 5 B, DK-1014 Copenhagen K, Denmark

Tel.: +45 35327914

Fax: +45 35327907




Prediction tools are increasingly used to inform patients about the future dental health outcome. Advanced statistical methods are required to arrive at unbiased predictions based on follow-up studies.

Materials and methods

The Internet risk calculator at the Dental Trauma Guide provides prognoses for teeth with traumatic injuries based on the Copenhagen trauma database: The database includes 2191 traumatized permanent teeth from 1282 patients that were treated at the dental trauma unit at the University Hospital in Copenhagen (Denmark) in the period between 1972 and 1991. Subgroup analyses and estimates of event probabilities were based on the Kaplan–Meier and the Aalen–Johansen method.


The Internet risk calculator shows individualized prognoses for the short- and long-term healing outcome of traumatized teeth with the following injuries: concussion, subluxation, extrusion, lateral luxation, intrusion, avulsion, crown fractures without luxation, root fractures and alveolar fractures. The prognoses for pulp necrosis, pulp canal obliteration, infection-related root resorption, ankylosis, surface resorption, marginal bone loss, and tooth loss were based on the tooth's root development stage and other risk factors at the time of the injury.


This article explains the database, the functionality and the statistical approach of the Internet risk calculator.