Background As the only active component in final treatment phase of Tip-Edge Plus technique, the activation of nickel-titanium orthodontic archwires is one of the factors that affect the torque expression. It is neces...Background As the only active component in final treatment phase of Tip-Edge Plus technique, the activation of nickel-titanium orthodontic archwires is one of the factors that affect the torque expression. It is necessary to evaluate the mechanical properties of the nickel-titanium wire used in the final treatment phase in simulated oral environments to forecast the treatment outcomes. Methods The mechanical properties of 171 thermal nickel-titanium wires of 0.35 mm （0.014-in） in diameters with different deflection of 40 mm in length were investigated with three-point bending test. The samples were divided into 2 groups： as-received and bended groups. In the bended group, samples were divided into 7 subgroups according to the amounts of deflection and named by the canine angulations （-25~, -19~, -13~, -7~, -1~, ＋5~, ＋11~）. The deflection of wires was made by inserting the wires into the deep tunnel of Tip-Edge Plus brackets positioned in plaster casts with different canine angulations to mimic the use of nickel-titanium wires in the final treatment phase. Immersed the bended group in artificial saliva （pH 6.8） and preserved at 37.0~C. Eight durations of incubation were tested： 1 to 8 weeks. Three analogous samples of each group and subgroups were tested per week. Stiffness （YS：E） and the load-deflection characteristics of unloading plateau section were obtained. Results Significant changes in specific mechanical properties were observed in long-term immersed and large deflected wires compared with as-received groups. Both immersion time and deflection affected the mechanical properties of wires in the simulated oral environment, and the two factors had synergistic effect. In groups -25~, -19~ and -13~, stiffness （YS：E） increased then decreased and average plateau force and ratio of variance decreased then increased correspondingly at specific time. Conclusions In the final treatment phase of Tip-Edge Plus technique, the mechanical properties of nickel-titanium wire are associated w展开更多
This study was undertaken to examine which factors contributed to the correction of crowding in two patients who underwent nonextraction orthodontic treatment. A study model analysis was conducted to determine the eff...This study was undertaken to examine which factors contributed to the correction of crowding in two patients who underwent nonextraction orthodontic treatment. A study model analysis was conducted to determine the effects of the orthodontic treatment for crowding with high canines on crown angulation and dental arch width in two patients. The results showed that the crown angulation was significantly increased, indicating distal tipping in the maxillary dental arch. This tendency was most commonly observed in the premolars among the lateral teeth. With respect to the dental arch width, the largest change was evident in the first molar and first premolar regions in cases 1 and 2, respectively. On the basis of these results, up-righting of mesially tipped lateral teeth and expansion of narrow dental arches could prove to be the keys to the success of space regaining or correction of high canines and mild crowding.展开更多
Objective: The aim of study was to evaluate the nature of mesiodistal angulation of the posterior teeth in patients with maxillary high canine, and to identify possible associations of crowding with mesial axial angul...Objective: The aim of study was to evaluate the nature of mesiodistal angulation of the posterior teeth in patients with maxillary high canine, and to identify possible associations of crowding with mesial axial angulation of the maxillary posterior teeth. Methods: The present study included seven Japanese male and 23 Japanese female patients. Study models were analyzed to evaluate the effectiveness of orthodontic treatment. A protractor was used to measure crown angulations, which were measured with reference to the posterior angle between the functional occlusal plane (FOP) and the long axis of the clinical crown of the lateral teeth and first molars. A sliding digital caliper was used to measure dental arch widths. Changes in the rotation of the maxillary molars were analyzed using “occlu-sograms”, which were printed from photographs of the occlusal aspect of the study model. Results: The maxillary teeth interacted with one another in the alveolar bone, resulting in progressive mesial tipping of the posterior teeth before orthodontic treatment. After orthodontic treatment, the angle relative to the FOP exhibited a significant increase, indicating that the maxillary teeth underwent distally directed uprighting (P P Conclusions: Based on the results, both uprighting of mesially tipped lateral teeth and expansion of narrow dental arches could prove to be keys to success in space regaining or correction of high canines and mild crowding.展开更多
目的:采用锥形束CT测量对不同垂直骨面型成人骨性Ⅱ类错[牙合]患者上颌尖牙冠根角及其周围骨结构进行分析。方法:采用KaVo 3D eXam CBCT机拍摄获得60名成人骨性Ⅱ类错[牙合]患者(年龄18~30岁)的颅颌面三维影像,根据头颅侧位片中FMA、SN...目的:采用锥形束CT测量对不同垂直骨面型成人骨性Ⅱ类错[牙合]患者上颌尖牙冠根角及其周围骨结构进行分析。方法:采用KaVo 3D eXam CBCT机拍摄获得60名成人骨性Ⅱ类错[牙合]患者(年龄18~30岁)的颅颌面三维影像,根据头颅侧位片中FMA、SN-MP角的大小分为低角组(n=16)、均角组(n=25)、高角组(n=19),对上颌双侧尖牙冠根角、牙槽骨附着高度、牙槽骨厚度等进行测量。结果:3组患者上颌尖牙唇、腭侧牙槽骨附着高度以及唇侧牙槽嵴顶水平牙槽骨厚度差异无统计学意义(P均>0.05)。上颌尖牙根尖水平唇、腭侧及总牙槽骨厚度高角组<均角组<低角组(P均<0.05)。上颌尖牙唇、腭侧旋转移动距离和最大旋转距离高角组<均角组<低角组(P均<0.05)。上颌尖牙冠根角高角组>均角组>低角组(P<0.05)。结论:不同垂直骨面型成人骨性Ⅱ类错[牙合]患者上颌尖牙冠根角及周围骨结构存在差异,正畸矫治过程中进行牙体移动设计时应多加注意。展开更多
文摘Background As the only active component in final treatment phase of Tip-Edge Plus technique, the activation of nickel-titanium orthodontic archwires is one of the factors that affect the torque expression. It is necessary to evaluate the mechanical properties of the nickel-titanium wire used in the final treatment phase in simulated oral environments to forecast the treatment outcomes. Methods The mechanical properties of 171 thermal nickel-titanium wires of 0.35 mm （0.014-in） in diameters with different deflection of 40 mm in length were investigated with three-point bending test. The samples were divided into 2 groups： as-received and bended groups. In the bended group, samples were divided into 7 subgroups according to the amounts of deflection and named by the canine angulations （-25~, -19~, -13~, -7~, -1~, ＋5~, ＋11~）. The deflection of wires was made by inserting the wires into the deep tunnel of Tip-Edge Plus brackets positioned in plaster casts with different canine angulations to mimic the use of nickel-titanium wires in the final treatment phase. Immersed the bended group in artificial saliva （pH 6.8） and preserved at 37.0~C. Eight durations of incubation were tested： 1 to 8 weeks. Three analogous samples of each group and subgroups were tested per week. Stiffness （YS：E） and the load-deflection characteristics of unloading plateau section were obtained. Results Significant changes in specific mechanical properties were observed in long-term immersed and large deflected wires compared with as-received groups. Both immersion time and deflection affected the mechanical properties of wires in the simulated oral environment, and the two factors had synergistic effect. In groups -25~, -19~ and -13~, stiffness （YS：E） increased then decreased and average plateau force and ratio of variance decreased then increased correspondingly at specific time. Conclusions In the final treatment phase of Tip-Edge Plus technique, the mechanical properties of nickel-titanium wire are associated w
文摘This study was undertaken to examine which factors contributed to the correction of crowding in two patients who underwent nonextraction orthodontic treatment. A study model analysis was conducted to determine the effects of the orthodontic treatment for crowding with high canines on crown angulation and dental arch width in two patients. The results showed that the crown angulation was significantly increased, indicating distal tipping in the maxillary dental arch. This tendency was most commonly observed in the premolars among the lateral teeth. With respect to the dental arch width, the largest change was evident in the first molar and first premolar regions in cases 1 and 2, respectively. On the basis of these results, up-righting of mesially tipped lateral teeth and expansion of narrow dental arches could prove to be the keys to the success of space regaining or correction of high canines and mild crowding.
文摘Objective: The aim of study was to evaluate the nature of mesiodistal angulation of the posterior teeth in patients with maxillary high canine, and to identify possible associations of crowding with mesial axial angulation of the maxillary posterior teeth. Methods: The present study included seven Japanese male and 23 Japanese female patients. Study models were analyzed to evaluate the effectiveness of orthodontic treatment. A protractor was used to measure crown angulations, which were measured with reference to the posterior angle between the functional occlusal plane (FOP) and the long axis of the clinical crown of the lateral teeth and first molars. A sliding digital caliper was used to measure dental arch widths. Changes in the rotation of the maxillary molars were analyzed using “occlu-sograms”, which were printed from photographs of the occlusal aspect of the study model. Results: The maxillary teeth interacted with one another in the alveolar bone, resulting in progressive mesial tipping of the posterior teeth before orthodontic treatment. After orthodontic treatment, the angle relative to the FOP exhibited a significant increase, indicating that the maxillary teeth underwent distally directed uprighting (P P Conclusions: Based on the results, both uprighting of mesially tipped lateral teeth and expansion of narrow dental arches could prove to be keys to success in space regaining or correction of high canines and mild crowding.
文摘目的:采用锥形束CT测量对不同垂直骨面型成人骨性Ⅱ类错[牙合]患者上颌尖牙冠根角及其周围骨结构进行分析。方法:采用KaVo 3D eXam CBCT机拍摄获得60名成人骨性Ⅱ类错[牙合]患者(年龄18~30岁)的颅颌面三维影像,根据头颅侧位片中FMA、SN-MP角的大小分为低角组(n=16)、均角组(n=25)、高角组(n=19),对上颌双侧尖牙冠根角、牙槽骨附着高度、牙槽骨厚度等进行测量。结果:3组患者上颌尖牙唇、腭侧牙槽骨附着高度以及唇侧牙槽嵴顶水平牙槽骨厚度差异无统计学意义(P均>0.05)。上颌尖牙根尖水平唇、腭侧及总牙槽骨厚度高角组<均角组<低角组(P均<0.05)。上颌尖牙唇、腭侧旋转移动距离和最大旋转距离高角组<均角组<低角组(P均<0.05)。上颌尖牙冠根角高角组>均角组>低角组(P<0.05)。结论:不同垂直骨面型成人骨性Ⅱ类错[牙合]患者上颌尖牙冠根角及周围骨结构存在差异,正畸矫治过程中进行牙体移动设计时应多加注意。
