Failure rates and associated risk factors of orthodontic – surgical treatment of impacted canines
Creators: name: Ζωγάκης, Ιωάννης Π.
Publisher: name: Aristotle University of Thessaloniki
Year: 2025
Subjects: Ορθοδοντική θεραπεία
Έγκλειστοι κυνόδοντες
Χειρουργική αποκάλυψη
Ποσοστό επιτυχίας
Προβλεπτικοί παράγοντες
Orthodontic treatment
Impacted canine(s)
Surgical exposure
Success rate
Predictor(s)

description: Σκοπός: Ο προσδιορισμός του ποσοστού αποτυχίας της ορθοδοντικής-χειρουργικής θεραπείας εγκλείστων κυνοδόντων και ο εντοπισμός προγνωστικών παραγόντων σχετιζόμενων με την αποτυχία, την αυξημένη διάρκεια θεραπείας και την ανάγκη επανεπέμβασης. Μέθοδος: Πανοραμικές ακτινογραφίες και κλινικά αρχεία 2594 ασθενών της Μεταπτυχιακής Κλινικής του Ορθοδοντικού Εργαστηρίου του ΑΠΘ ανακτήθηκαν και αναλύθηκαν αναδρομικά. Αποτελέσματα: Συμπεριελήφθησαν 106 έγκλειστοι κυνόδοντες, εκ των οποίων, 12 δεν ανέτειλαν επιτυχώς (ποσοστό αποτυχίας 11.3%). Ο μοναδικός παράγοντας αποτυχίας ήταν η αυξημένη ηλικία, ενώ η αυξημένη γωνίωση, η εγγύτητα στη μέση γραμμή και η επιλογή κλειστής αντί ανοιχτής χειρουργικής τεχνικής, ήταν παράγοντες κινδύνου αυξημένης διάρκειας κυνοδοντικής ευθυγράμμισης. Η ηλικία και η επιλογή της χειρουργικής προσέγγισης σχετίζονταν με την ανάγκη επανεπέμβασης. Συμπεράσματα: Καταγράφηκε ποσοστό αποτυχίας 11.3%. Ο μοναδικός προβλεπτικός παράγοντας αποτυχίας ήταν η ηλικία, ενώ η γωνίωση, η εγγύτητα στη μέση γραμμή και η χειρουργική τεχνική ήταν παράγοντες κινδύνου αυξημένης διάρκειας. Υπήρξε συσχέτιση μεταξύ της ηλικίας και της χειρουργικής προσέγγισης με ανάγκη επανεπέμβασης.
description: Introduction: An impacted tooth is a tooth having more than three-quarters of its root developed, that has not erupted and is unlikely to erupt soon. Canine impaction may affect functional occlusion and smile aesthetics, and lead to the development of pathologies, including cysts and resorption of adjacent teeth. Various treatment methods are available, aiming at its prevention or at its resolution. The orthodontic–surgical treatment is most widely used, if prevention is unsuccessful or not undertaken. The surgical part is performed using closed or open exposure. Aim: The main purpose was to determine the failure rate of orthodontic–surgical treatment of impacted canines. The secondary outcomes included the identification of risk factors of treatment failure, prolonged canine treatment and need for surgical reintervention. Material and methods: The study was a retrospective observational analysis of clinical records and panoramic radiographs of 2594 patients who consecutively visited the Postgraduate Clinic of the Department of Orthodontics of the School of Dentistry of the Aristotle University of Thessaloniki, Greece. Treatment was considered successful if full alignment of the impacted canine in the dental arch was achieved. Treatment duration was calculated from the surgical exposure date to the date the canine reached the arch, fully ligated into a nickel-titanium main archwire. The need for surgical reintervention was defined as the need to perform an additional procedure. Results: Prevalence of impacted canines was 4.2%, significantly higher in females (6.97 %) than males (2.32%). Transmigrant canines were solely mandibular (0.11% frequency). In total, 106 impacted canines were included, most maxillary (90.6%, n=96), as opposed to mandibular (9.4%, n = 10). Overall, 12 canines failed; reporting an 11.3% failure rate. Multivariable regressions were conducted. The only significant patient-related factor of treatment failure was age (aOR:1.2; 95%CI:1.1-1.3; P&lt;.001), while increased canine angulation (B:0.22; 95%CI:0.03-0.42; P=0.02) and proximity to midline (B:7.4; 95% CI:0.41-14.4; P=0.03) were significant predictors of increased duration. Closed versus open approach, was a significant treatment-related predictor of prolonged treatment (B:-6.01; 95%CI:-11.7-(-0.31); P=0.04). A need for reintervention was documented in 23 canines (21.7%), with 16 (69.6%) successfully aligned, while 7 (30.4%) failed. The most common cause was suspected ankylosis (n=9, 39.1%). Increased age (aOR:1.08; 95%CI:1.01-1.51; P&lt;0.05) and closed over open technique (aOR:0.2; 95%CI:0.05-0.77; P&lt;0.05), were significant predictors. Regarding two biomechanical systems for palatally impacted canines’ treatment, ballista springs were not significantly superior over cantilevers, regarding treatment success (P&gt;0.99) and duration (P=0.56). Brackets over eyelets as bonded attachments, though not significantly affecting treatment outcome (P=0.52), may lead to prolonged alignment (P=0.009). Conclusion: An 11.3% failure rate was documented. The only significant patient-related predictor of failure was increased patient’s age, while increased angulation and proximity to midline were risk factors for increased duration. Closed versus open technique was the only significant treatment-related predictor of prolonged alignment. Increased age and choice of closed over open approach were risk factors of need for surgical reintervention. Accounting for these factors during treatment planning, followed by an interdisciplinary approach, is essential for treatment success.