The purpose of this study was to compare the changes in root lengths and root surface areas that occur after treatment with two functional appliances the Twin Block (TWB) and Crown Herbst appliances. Methods: Forty patients (12 boys, 28 girls) were included in this study. Half of them were treated with the stainless steel Crown Herbst appliance (with crowns placed on the first molars and the first and second premolars), and the other half were treated with the TWB appliance. Panoramic and cephalometric films were obtained before treatment (T1) and after the functional treatment (T2). All upper and lower teeth except second and third molars were analysed with the ImageJ software (version 1.37, National Institutes of Health, Bethesda) on panoramic films. Root length and area values were compared using t-tests. Results: The intragroup comparison showed that root length values were significantly decreased in right and left mandibular incisors and canines in the Crown Herbst group (12 years 7 months [+ or -] 9 months). However, significantly increased root length was observed in right and left maxillary second premolars and right maxillary first premolar in the TWB group (11 years 1 month [+ or -] 4 months). The intergroup comparison indicated that root length values were significantly decreased in right maxillary premolars, right and left mandibular laterals and left mandibular canine in the Crown Herbst group when compared with those in the TWB group. Conclusion: It was concluded that the Crown Herbst group showed a greater tendency for decreased root length than the TWB group. In orthopaedic correction of Class II malocclusions, in the absence of any contraindications, TWB appliance may be preferred for the promotion of root development. Keywords: Orthodontics, malocclusion, root resorption, radiography
Bu calijmanin amaci, Twin Block (TWB) ve Kron Herbst apareyleri ile yapilan fonksiyonel tedavilerin dislerin kok uzunluklari ve kok yuzey alanlarina etkisini karsilastirmaktir. Yontemler: Bu centsalismaya kirk hasta (12 erkek, 28 kiz) dahil edilmis olup, bunlarin yarisi paslanmaz centselik Kron Herbst apareyi ile (birinci molar, birinci ve ikinci premolarlara yerlestirilen kronlar ile) ve diger yarisi ise TWB apareyi ile tedavi edilmistir. Calismaya dahil edilen hastalardan panoramik ve sefalometrik filmler tedaviden once (T1) ve fonksiyonel tedaviden sonra (T2) elde edilmistir. Ikinci ve ucuncu molar disler disindaki tum ust ve alt disler, panoramik filmler uzerinde ImageJ yazilimi (version 1,37, National Institutes of Health, Bethesda) kullanilarak analiz edilmistir. Kok uzunlugu ve alan degerleri t-testi kullanilarak karsilastirilmistir. Bulgular: Grup ici karsilastirmada, Kron Herbst grubundaki (12 yas 7 ay [+ or -] 9 ay) sag ve sol mandibular kesici disler ve kaninlerde kok uzunluk degerlerinin anlamli derecede azaldigi gozlendi. Bununla birlikte, TWB grubunda (11 yas 1 ay [+ or -] 4 ay) sag ve sol maksiller ikinci premolar ve sag maksiller birinci premolarda kok uzunlugunda anlamli bir artis gozlendi. Gruplar arasi karsilastirma, Kron Herbst grubunda TWB grubuna gore sag maksiller premolar, sag sol mandibular lateraller ve sol mandibular kaninlerde kok uzunluk degerlerinin anlamli olarak azaldigini gostermistir. Sonuc: Kron Herbst grubunda bulunan dislerin kok rezorpsiyonu riski TWB grubundan daha fazlaydi. Sinif II malokluzyonlarinin ortopedik duzeltmesinde, kontrendikasyon yoksa, kok gelisiminin desteklenmesi bakimindan TWB cihazi tercih edilebilir. Anahtar Sozcukler: Ortodonti, malokluzyon, kok rezorpsiyonu.
