Effective Uprighting Method for Horizontally Impacted Lower Third Molar: The Modified Bonded Cantilever Spring
Lecture Description
Introduction : Introduction: It has been reported that a maxillary or a mandibular permanent third molar was uprighted and acceptably replaced the second molar after extraction in orthodontic treatment. The alignment of the permanent third molars after the extraction of the permanent first or second molars is a useful option for adult patients when the permanent first or second molars are severely damaged.
Discussion : Discussion: Several orthodontic mechanics and devices have been proposed to verticalize and disimpact the mesially tipped mandibular molars. Removable and fixed appliances and, more recently, skeletal anchorage have been used with push springs, open-coil and closed-coil springs tip-back cantilevers, looped springs to perform the challenging task of uprighting tipped molars. A clinical advantage of the modified bonded cantilever spring is that it does not depend on exposure of the buccal surface of the tooth for bonding of orthodontic tube, as generally required by conventional cantilevers, because this area is frequently unavailable in patients with extremely tipped and partially erupted mandibular molars. Another mechanical advantage is that the moment produced by the modified bonded cantilever spring, unlike some uprighting mechanics, does not depend on any distal force. Extremely tipped mandibular molars frequently have the center of resistance close to the line of action of the distal forces, generating reduced moments of force and tending to produce distal bodily movement of the tipped molar, which can reduce molar uprighting efficiency. Therefore, this mechanical characteristic can be an effective method when root movement is prioritized.
Conclusion : Conclusion: the modified bonded cantilever spring is an effective mechanics for uprighting of horizontally impacted lower third molar without surgical exposure of buccal tooth surface.
October 28-30, 2022 ¡¤ COEX, Seoul, Korea