The use of panoramic radiographs to decide when interceptive extraction is beneficial in children with palatally displaced canines based on a randomized clinical trial.

Objective: To evaluate which palatally displaced canines (PDCs) benefit from interceptive extraction of the deciduous canine, to assess possible side effects from the extraction, and to analyse other dental deviations in patients with PDCs.

Design, Settings, Participants, And Intervention: A sample of 67 patients (40 girls, mean age: 11.3 ± 1.1; 27 boys, mean age ± SD: 11.4 ± 0.9) with unilateral (45) or bilateral (22) PDCs were consecutively recruited and randomly allocated to extraction or non-extraction using block randomization. No patients dropped out after randomization or during the study. The patients were given a clinical examination and panoramic radiographs were taken at baseline and after 6 (T1) and 12 months (T2). An individual therapy plan was made for the PDCs that had not erupted at T2. Measurements were performed blindly and the outcome measures were: canine position and angulation, root development, midline shift, rotation, or movement of adjacent teeth into the extraction site, and frequency of other dental deviations.

Results: Interceptive deciduous canine extraction is beneficial if the alpha angle is between 20 and 30 degrees. A PDC located in sector 4 with an alpha angle >30 degrees should have immediate surgical exposure, while canines angulated less than 20 degrees and located in sector 2 can be observed without prior interceptive extraction. Deciduous canine extraction was more beneficial in younger patients with less advanced root development. Minor side effects, such as rotation or migration of teeth into the extraction space, were observed in 15 out of 35 patients. A majority of the patients had other dental deviations than PDC in the dentition.

Limitations: The results are only valid for patients with no space deficiency in the maxilla and with PDCs located in sector 2-4.

Harms: No harms were detected.

Conclusions: The alpha angle and sector position are good diagnostic predictors of when interceptive extraction is beneficial. Minor side effects are seen after the extraction and the majority of the patients had other dental deviations too.

Registration: This trial was registered at http://www.fou.nu/is/sverige, registration number: 211141.