Üst kesici dişlerin retraksiyonunda manyetik kuvvetlerin kullanılması ve farklı bir retraksiyon sistemi ile karşılaştırılması

Abstract

THE USE OF THE MAGNETIC FORCES IN THE RETRACTION OF THE UPPER INCISORS AND ITS COMPARISON WITH A DIFFERENT RETRACTION SYSTEM Dt. Tamer TÜRK Doç.Dr. Müfide DİNÇER Gazi Üniversitesi Dişhekimliği Fakültesi Ortodonti Anabilim Dalı 1995 Doktora İNGİLİZCE ÖZET The aim of this study was the evaluation of the clinical usefulness and the effects of an attractive magnetic retraction system producing an increasing force which passes through the assumed center of resistance of the upper incisors, and the comparison of this magnetic retraction system with a closed coil spring retraction system producing a decreasing force, likewise passing through the assumed center of resistance of the upper incisors during the retraction of these teeth. 22 cases with Angle class I and/or class II malocclusion and with a symmetrical extraction space of at least 3 mm following canine distalization were included into this research. Two groups each consisting of 11 cases, 10 girls and 1 boy, were composed and these cases were matched according to their skeletal ages. At the beginning and at the end of this study lateral cephalometric, hand- wrist, panoramic and periapical radiographs, photographs and orthodontic models were obtained from first and second group, their skeletal ages were 17 years and 2 months and 17 years and 3 months, respectively. In the first study group, for the retraction of the upper incisors, a 3X4.4X2.8 mm neodymium-iron-boron (NdFeB) magnet, producing an increasing force T.G. YÜKSEKSSKHM l^. which passes through the assumed center of resistance, located 3ti)((}g£fM^$i $&k^rmm distal from the center of the lateral bracket, was used. The magnet was activated to produce an initial force of 110 grams, i.e the distance between the attractive surfaces being 3 mm. In the second study group, a stainless steel closed coil spring sized 0.008X0.030` and 7 mm long, producing a decreasing force which also passes through the assumed center of resistance, was used. The coil spring was activated 4.5 mm to produce an initial force of 150 grams. The time of retraction of the upper incisors for the the first and second study group was 98.64 + 23.17 days and 103.82 + 20.89 days, respectively. To examine the type of movement of anterior and posterior teeth, and the time and speed of extraction space closure 33 parameters were measured and evaluated statistically. The retraction of the upper incisors occurred with the forces generated by the magnets. In both study groups, the type of movement of the upper incisors was of a tipping nature during retraction. In the magnetic retraction group, the center of rotation was located in an area bounded by the root apex and a 5.5 mm distance below, coronally, the root apex. In the coil spring retraction group, the center of rotation was located at the root apex and above the root apex. In both study groups, a forward movement of the posterior teeth was perceived. No differences were observed in the time and speed of the closure of extraction space between the magnetic and coil spring retraction group. M e~^nHB%S!fifiSi^

THE USE OF THE MAGNETIC FORCES IN THE RETRACTION OF THE UPPER INCISORS AND ITS COMPARISON WITH A DIFFERENT RETRACTION SYSTEM Dt. Tamer TÜRK Doç.Dr. Müfide DİNÇER Gazi Üniversitesi Dişhekimliği Fakültesi Ortodonti Anabilim Dalı 1995 Doktora İNGİLİZCE ÖZET The aim of this study was the evaluation of the clinical usefulness and the effects of an attractive magnetic retraction system producing an increasing force which passes through the assumed center of resistance of the upper incisors, and the comparison of this magnetic retraction system with a closed coil spring retraction system producing a decreasing force, likewise passing through the assumed center of resistance of the upper incisors during the retraction of these teeth. 22 cases with Angle class I and/or class II malocclusion and with a symmetrical extraction space of at least 3 mm following canine distalization were included into this research. Two groups each consisting of 11 cases, 10 girls and 1 boy, were composed and these cases were matched according to their skeletal ages. At the beginning and at the end of this study lateral cephalometric, hand- wrist, panoramic and periapical radiographs, photographs and orthodontic models were obtained from first and second group, their skeletal ages were 17 years and 2 months and 17 years and 3 months, respectively. In the first study group, for the retraction of the upper incisors, a 3X4.4X2.8 mm neodymium-iron-boron (NdFeB) magnet, producing an increasing force T.G. YÜKSEKSSKHM l^. which passes through the assumed center of resistance, located 3ti)((}g£fM^$i $&k^rmm distal from the center of the lateral bracket, was used. The magnet was activated to produce an initial force of 110 grams, i.e the distance between the attractive surfaces being 3 mm. In the second study group, a stainless steel closed coil spring sized 0.008X0.030` and 7 mm long, producing a decreasing force which also passes through the assumed center of resistance, was used. The coil spring was activated 4.5 mm to produce an initial force of 150 grams. The time of retraction of the upper incisors for the the first and second study group was 98.64 + 23.17 days and 103.82 + 20.89 days, respectively. To examine the type of movement of anterior and posterior teeth, and the time and speed of extraction space closure 33 parameters were measured and evaluated statistically. The retraction of the upper incisors occurred with the forces generated by the magnets. In both study groups, the type of movement of the upper incisors was of a tipping nature during retraction. In the magnetic retraction group, the center of rotation was located in an area bounded by the root apex and a 5.5 mm distance below, coronally, the root apex. In the coil spring retraction group, the center of rotation was located at the root apex and above the root apex. In both study groups, a forward movement of the posterior teeth was perceived. No differences were observed in the time and speed of the closure of extraction space between the magnetic and coil spring retraction group. M e~^nHB%S!fifiSi^