摘要
目的观察青少年下颌第一恒磨牙在生长发育过程中发生生理性移动的现象和规律。方法选择11名正常生长发育个体8~16岁的头颅侧位片进行下颌金属标记钉重叠和测量,分析下颌第一恒磨牙移动规律。结果8~16岁下颌第一恒磨牙近中牙尖相对下颌基骨平均向近中移动(3.63±1.29)mm,向方移动(5.92±1.78)mm,统计学差异显著(P<0.05);下颌第一恒磨牙近中移动最快的时期是10~12岁,平均近中移动(1.52±1.25)mm;下颌第一恒磨牙向移动与下颌骨生长量(Co-Gn)强相关(r=0.623,P<0.01)。结论在不受正畸干预的情况下,下颌第一恒磨牙随着生长发育持续向近中移动;下颌第一恒磨牙的垂直向生长与下颌骨的生长节律一致,提示下颌磨牙的垂直向移动是牙列对下颌骨垂直向生长的适应性表现。
ObjectiveTo observe the physiological displacement of mandibular first molar during growth and to explain this phenomenon.Methods11 untreated adolescents with normal occlusion were selected from the longitudinal sample with implants collected by Dr. J. R. Mathews, UCSF, in the 1970s. 7 males and 4 females are included in this sample, and all of them had lateral cephalograms annually taken from 8 to 16 years old. All the cephalograms are traced and superimposed with aid of the implants. The displacement and tipping of mandibular first molars are measured on the cephalograms.ResultsRelative to the mandibular, the average mesial displacement of mandibular first molar mesial-buccal cusp was (3.63±1.29)mm from 8 to 16 years old, and the average vertical displacement was (5.92±1.78)mm(P<0.05). The tipping of mandibular first molar showed no significant change. Mandibular first molar moved at the fastest rate from 10 to 12 years old, during which time (1.52±1.25)mm mesial displacement was observed. Pearson correlation test showed that there was significant correlation(r=0.623, P<0.01) between vertical displacement of mandibular first molar and mandibular growth(Co-Gn). ConclusionsFor the individuals with growth potential, mandibular first molar will continue to move misally without mechanical force. The vertical displacement of mandibular first molar and mandibular growth(Co-Gn) are at the same pace, which implies an adaptive pattern of dental and skeletal vertical growth.
作者
梁奕
张晓芸
许天民
Liang Yi;Zhang Xiaoyun;Xu Tianmin(Department of Orthodontics,Peking University School and Hospital of Stomatology ,Beijing 100081 ,China)
出处
《中华口腔正畸学杂志》
2018年第4期210-215,共6页
Chinese Journal of Orthodontics
基金
科技部国家国际合作项目(30313032401).
关键词
生长发育
下颌第一磨牙
金属标记钉研究
Dental and Skeletal Growth
Mandibular First Molar
Implant Study
