目的针对安氏Ⅰ类双颌前突患者,采用个性化舌侧矫治器,确定前牙内收后牙槽骨的改建情况,为正畸治疗中牙齿在牙槽骨内的安全移动提供参考依据。方法选择15例安氏Ⅰ类双颌前突拔牙患者,采用个性化舌侧矫治器,获取其治疗前后牙尖交错位的C...目的针对安氏Ⅰ类双颌前突患者,采用个性化舌侧矫治器,确定前牙内收后牙槽骨的改建情况,为正畸治疗中牙齿在牙槽骨内的安全移动提供参考依据。方法选择15例安氏Ⅰ类双颌前突拔牙患者,采用个性化舌侧矫治器,获取其治疗前后牙尖交错位的CBCT图像,使用SimPlant Pro 13.0软件测量并使用SPSS20.0软件对患者治疗前后测量数据进行配对t检验及相关统计学分析。结果采用舌侧矫治器内收前牙后,上前牙根尖部位的唇侧牙槽骨厚度增加,腭侧牙槽骨厚度减小;上下前牙腭侧牙槽骨高度均降低,舌侧骨开裂加重,个别牙齿唇侧骨开窗率降低。结论安氏Ⅰ类双颌前突患者舌侧矫治前后,牙槽骨并没有随牙齿移动同等程度改建,治疗后牙槽骨以骨吸收为主,骨增生有限。展开更多
Background The shape memory effect of nickel-titanium （NiTi） archwires is largely determined by the phase transition temperature. It is associated with a reversible transformation from martensite to austenite. The a...Background The shape memory effect of nickel-titanium （NiTi） archwires is largely determined by the phase transition temperature. It is associated with a reversible transformation from martensite to austenite. The aim of this study was to characterize austenite, martensite and R phase temperatures as well as transition temperature ranges of the commonly used clinical NiTi orthodontic arch wires selected from several manufacturers. Methods Differential scanning calorimetry （DSC） method was used to study the phase transformation temperatures and the phase transition processes of 9 commonly used clinical NiTi alloys （types： 0.40 mm （0.016 inch）, 0.40 mm × 0.56 mm （0.016 inch × 0.022 inch））.Results The austenite finish temperatures （Af） of 0.40 mm Smart, Ormco and 3M NiTi wires were lower than the room temperature, and no phase transformation was detected during oral temperature. Therefore, we predicted that these types of NiTi did not possess shape memory property. For 0.40 mm and 0.40 mm × 0.56 mm Youyan I NiTi wires, no phase transformation was detected during the scanning temperature range, suggesting that these two types of wires did not possess shape memory either. The Af of 0.40 mm × 0.56 mm Smart, L＆H, Youyan II Ni-Ti wires were close to the oral temperature and presented as martensitic-austenitic structures at room temperature, suggesting the NiTi wires listed above have good shape memory effect. Although the 0.40 mm × 0.56 mm Damon CuNiTi wire showed martensitic- austenitic structures at oral temperature, its Af was much higher than the oral temperature. It means that transformation from martensite to austenite for this type of NiTi only finishes when oral temperature is above normal. Conclusion The phase transformation temperatures and transformation behavior varied among different commonly used NiTi orthodontic arch wires, leading to variability in shape memory effect.展开更多
文摘目的针对安氏Ⅰ类双颌前突患者,采用个性化舌侧矫治器,确定前牙内收后牙槽骨的改建情况,为正畸治疗中牙齿在牙槽骨内的安全移动提供参考依据。方法选择15例安氏Ⅰ类双颌前突拔牙患者,采用个性化舌侧矫治器,获取其治疗前后牙尖交错位的CBCT图像,使用SimPlant Pro 13.0软件测量并使用SPSS20.0软件对患者治疗前后测量数据进行配对t检验及相关统计学分析。结果采用舌侧矫治器内收前牙后,上前牙根尖部位的唇侧牙槽骨厚度增加,腭侧牙槽骨厚度减小;上下前牙腭侧牙槽骨高度均降低,舌侧骨开裂加重,个别牙齿唇侧骨开窗率降低。结论安氏Ⅰ类双颌前突患者舌侧矫治前后,牙槽骨并没有随牙齿移动同等程度改建,治疗后牙槽骨以骨吸收为主,骨增生有限。
文摘Background The shape memory effect of nickel-titanium （NiTi） archwires is largely determined by the phase transition temperature. It is associated with a reversible transformation from martensite to austenite. The aim of this study was to characterize austenite, martensite and R phase temperatures as well as transition temperature ranges of the commonly used clinical NiTi orthodontic arch wires selected from several manufacturers. Methods Differential scanning calorimetry （DSC） method was used to study the phase transformation temperatures and the phase transition processes of 9 commonly used clinical NiTi alloys （types： 0.40 mm （0.016 inch）, 0.40 mm × 0.56 mm （0.016 inch × 0.022 inch））.Results The austenite finish temperatures （Af） of 0.40 mm Smart, Ormco and 3M NiTi wires were lower than the room temperature, and no phase transformation was detected during oral temperature. Therefore, we predicted that these types of NiTi did not possess shape memory property. For 0.40 mm and 0.40 mm × 0.56 mm Youyan I NiTi wires, no phase transformation was detected during the scanning temperature range, suggesting that these two types of wires did not possess shape memory either. The Af of 0.40 mm × 0.56 mm Smart, L＆H, Youyan II Ni-Ti wires were close to the oral temperature and presented as martensitic-austenitic structures at room temperature, suggesting the NiTi wires listed above have good shape memory effect. Although the 0.40 mm × 0.56 mm Damon CuNiTi wire showed martensitic- austenitic structures at oral temperature, its Af was much higher than the oral temperature. It means that transformation from martensite to austenite for this type of NiTi only finishes when oral temperature is above normal. Conclusion The phase transformation temperatures and transformation behavior varied among different commonly used NiTi orthodontic arch wires, leading to variability in shape memory effect.
