Root resorption diagnosed with cone beam computed tomography after 6 months and at the end of orthodontic treatment with fixed appliances

Abstract

Objective: To investigate the prevalence of orthodontically induced root resorption after treatment and the correlation with resorption found after 6 months of treatment.

Materials and methods: One hundred fifty-six patients (11-18 years) treated with fixed appliances and extraction of four premolars were examined with cone beam computed tomography before treatment, after 6 months of treatment (n = 97), and at the end of active treatment. The Malmgren Index was used to describe the degree of root resorption.

Results: Severe root resorption (>2 mm, score 3) was found in 25.6% of the patients at the end of treatment. Extreme root resorption was found in one patient. Root resorption was seen more frequently in the maxillary incisor region. There was no correlation between the severity of root resorption after 6 months and the amount observed at the end of treatment. Furthermore, no correlation was seen between treatment duration and the severity of root resorption.

Conclusions: Clinically significant resorption was diagnosed in 25.6% of the patients, but no correlations, either with the resorption seen after 6 months or with the length of treatment, were found. Radiographic examination after 3 to 6 months of orthodontic treatment is too early and will not reduce the number of patients who will have teeth with severe root resorption.

Figures

Figure 1.

Index for subjective scoring of root resorption according to Malmgren et al. 1 indicates irregular root contour; 2, apical root resorption less than 2 mm of original root length; 3, apical root resorption from 2 mm to one-third of original root length; 4, apical root resorption exceeding one-third of original root length.

Figure 2.

Distribution of root resorbed teeth (scores 2–4) according to the counts in each tooth group at the end of treatment.

Figure 3.

Distribution of patients with different root resorption scores in relation to the treatment duration.

Figure 4.

Flow chart of patients with different root resorption scores at 6 months and changes until the end of treatment.