Sara Rizell

Summary Objectives To study, longitudinally, the development of apical root resorptions (ARRs) in Turner syndrome (TS) and to correlate these to the karyotype and orthodontic treatment. Materials and methods Thirty girls with TS participated in the study, mean age 10.8 years (6.6–23.4) at the first registration (T1), and 14.3 years (9.2–25.2) at the second registration (T2). Forty girls without TS, orthodontically untreated, served as controls. ARR was diagnosed in panoramic radiographs, and root/crown ratios of the lower permanent first molar were measured at T1 and T2 with a mean follow-up period of 42 (11–89) months. Results During the follow-up period, ARR was seen in 40% of all TS patients and in 2.5% in the control group. The majority displayed ARR on the distal root of the mandibular first permanent molars (30%). ARR at T2 was seen in 56% of 45,X and isochromosome karyotype and 21% of every other TS karyotype patients. AAR was seen in 5 out of 12 TS patients with orthodontic treatment. No statistically significant differences in root/crown ratios between T1 and T2 were found. Limitations The number of patients studied is limited, thus possible differences might be disguised for this reason. Spatial projection errors in panoramic radiograph recordings might have influenced measurement, resulting in an underestimation of ARR. Conclusions There is a higher risk for ARR in girls with TS and probably the risk is therefore probably also higher during orthodontic treatment. Thus, if treated, frequent radiographic follow-ups should be taken during the treatment. Protocol The protocol was not published before trial commencement.