变异式保持器治疗第一恒磨牙异位萌出的临床应用

目的探讨变异式保持器治疗第一恒磨牙异位萌出的临床应用效果。方法选择临床25例上颌第一恒磨牙异位萌出的患儿,年龄7~9岁,其中10例双侧,15例单侧,通过传统的Nance弓焊接远端牵引钩,在异位萌出的第一恒磨牙牙合面,联合应用链状橡皮圈推第一恒磨牙向远中以达到其正常的生理位置。结果 25例接受治疗的患儿均完成了治疗,且疗效明显,异位的第一恒磨牙均萌出到了正常位置。结论变异式保持器用于治疗第一恒磨牙异位萌出疗效显著,操作简便,适合在临床推广。     

第一恒磨牙异位萌出治疗方案选择的考量

第一恒磨牙异位萌出分为可逆性异位萌出和不可逆性异位萌出.第一恒磨牙异位萌出的临床危害主要是造成间隙丧失、牙弓长度减少等.本文通过3例推第一恒磨牙向远中开展间隙的病例,阐述第一恒磨牙异位萌出治疗方案选择的考量.     

上颌第一恒磨牙异位萌出的治疗

上颌第一恒磨牙异位萌出是磨牙向近中萌出角度较大或萌出受阻，导致上颌第二乳磨牙有非典型的吸收，使磨牙近中萌出，引起错骀畸形^[1]。异位萌出在人口发生率为2％-4．3％^[2,3]。因此，牙科医生要警惕并重视这种情况。本文通过对32例上颌第一恒磨牙异位萌出的治疗，探讨对该类患者的矫治方法及有关问题。     

上颌第二恒磨牙不同萌出状态的安氏Ⅱ~1类患者应用口外弓治疗前后的头影测量研究

目的评价应用口外弓非拔牙矫治上颌第二恒磨牙不同萌出状态的安氏Ⅱ1类错畸形的临床效果。方法选择恒牙期应用口外弓进行非拔牙矫治的安氏Ⅱ1类错畸形患者36例,年龄10～15岁,平均12.5岁。根据上颌第二恒磨牙萌出状态分为4组,测量所有患者治疗前、后头颅侧位片,采用方差分析方法比较治疗效果。结果矫治前后的显著性改变主要发生在上颌,上颌第二磨牙牙胚位于上颌第一磨牙颈部以下组有统计学意义的指标最多(SNA、ANB、Wits距、U6-Ptv、over-jet),且明显优于其他3组。结论口外弓颈牵引能有效改善恒牙期深覆盖,矫正磨牙关系,在上颌第二恒磨牙未萌,特别是其牙胚尚处于第一恒磨牙颈部以下时采用此方法效果最好。     

早期远移磨牙矫治上颌第二前磨牙阻生的临床研究

目的:探讨远中移动上颌第一磨牙,结合直丝弓矫治伴有第二前磨牙阻生的II类错畸形的有效性。方法:选取处于替牙晚期、上颌中重度拥挤的24例患者,采用活动矫治器单侧或双侧远移上颌第一磨牙,开辟间隙并进行第二期固定矫治;统计学分析治疗前后的X线头影测量结果,评估临床疗效。结果:上颌第一磨牙平均远中移动4.5 mm,两侧磨牙和尖牙达到I类关系,上颌前牙唇倾度增加。结论:早期远中移动上颌第一磨牙并结合直丝弓技术可促进第二磨牙正常萌出。     

弹弓式磨牙远移器治疗上颌第一恒磨牙异位萌出

目的评价使用弹弓式磨牙远移器治疗第一恒磨牙异位萌出的临床效果。方法选择替牙期不可逆性第一恒磨牙异位萌出患者8例,男3例,女5例,年龄6.8~9.5岁,平均8.6岁。所有病例均存在不同程度的第二乳磨牙远中根吸收。采用弹弓式磨牙远移器标准型或简化型矫治器治疗,推第一恒磨牙向远中移动,使第一恒磨牙与第二乳磨牙远中面脱离接触并最终萌出到正常位置。结果所有病例第一恒磨牙牙冠均向远中移动并竖直,与第二乳磨牙脱离接触。治疗时间1.5~4.0个月,平均2.2个月。结论弹弓式磨牙远移器是治疗第一恒磨牙异位萌出的有效方法。     

上颌磨牙远心移动装置及疗效分析

上颌磨牙远心移动是牙齿矫正治疗的难点 ,一般矫正装置难以达到临床要求。近年来 ,我们将美国正畸学专家ＨｉｌｇｅｒｅｓＪ .Ｊ .1994年提出的Ｐｅｎｄｕｌｕｍａｐｐｌｉａｎｃｅ上颌磨牙远心移动装置加以改进 ,在临床上应用 ,矫治患者 12例 ,取得良好的矫治效果。材　料　与　方　法1　临床资料 :　患者 12例 ,男 3例 ,女 9例。年龄 10～ 16岁 ,替牙期 2例 ,恒牙期 10例 ,其中第二恒磨牙已萌出者 4例。采用拔除第二磨牙推第一磨牙远心移动矫治 2例。 12例患者磨牙远心移动最小距离 4 0ｍｍ ,最大达 7 5ｍｍ。2　装置制作与应用 :2 1　…     

改良摆式矫治器联合口外弓矫治安氏Ⅱ1错（牙合）19例报告

目的:探讨改良摆式矫治器联合口外弓矫治安氏Ⅱ1错牙合的临床疗效.方法:应用改良摆式矫治器及口外弓对19例平均年龄13.4岁,第二磨牙已萌出的牙性安氏Ⅱ1错牙合进行治疗,进行矫治前后X线头影测量分析.结果:改良摆式矫治器联合口外弓,能同时推第一、第二磨牙向远中移动,直至磨牙为Ⅰ类或偏近中关系,上颌磨牙平均每月向远中移动1.3 mm.并能同步打开咬合,导下颌向前.结论:改良摆式矫治器联合口外弓矫治牙性Ⅱ1错牙合是一种较好的方法.     

改良摆式矫治器联合口外弓矫治安氏Ⅱ~1错19例报告

目的 :探讨改良摆式矫治器联合口外弓矫治安氏Ⅱ1错牙合的临床疗效。方法 :应用改良摆式矫治器及口外弓对 19例平均年龄 13 .4岁 ,第二磨牙已萌出的牙性安氏Ⅱ1错牙合进行治疗 ,进行矫治前后X线头影测量分析。结果 :改良摆式矫治器联合口外弓 ,能同时推第一、第二磨牙向远中移动 ,直至磨牙为Ⅰ类或偏近中关系 ,上颌磨牙平均每月向远中移动 1.3mm。并能同步打开咬合 ,导下颌向前。结论 :改良摆式矫治器联合口外弓矫治牙性Ⅱ1错牙合是一种较好的方法。     

口外弓结合滑动杆推单侧上颌磨牙的X线头影分析

安氏Ⅱ类错畸形伴有前牙轻度拥挤病例的非拔牙矫治 ,通过推上颌磨牙远移纠正磨牙关系 ,开展牙间隙已逐渐成为一种重要手段。本研究目的是探讨口外弓结合滑动杆推单侧上颌磨牙远移的效果 ,通过其治疗前后的Ｘ线头影侧位定位片的分析 ,评价其矢状 ,垂直方向的变化。一、材料与方法研究采用随机抽样的方法 ,治疗 10例患者 ,女性 7例 ,男性 3例 ,平均年龄 15岁 11月 (± 1岁 1月 ) ,均为安氏Ⅱ类磨牙关系 ,上颌第二磨牙 5例完全萌出、3例部分萌出、2例拔除 ,下颌位基本正常。1 矫治器的设计和施力　常规装配方丝弓矫治器 ,推磨牙远移时使用Φ0…     

Ectopic eruption of the maxillary first permanent molar: etiologic factors

For clinical handling, it is important to determine whether any etiologic factors, alone or in combination, are of more importance than others in causing ectopic eruption of a maxillary first permanent molar. Etiologic factors involved in ectopic eruption of maxillary first permanent molars were investigated in 129 children with a mean age of 8.6 years. Ninety-two children (fifty-eight boys and thirty-four girls) had ectopic eruption and thirty-seven children served as controls and were matched by age and sex. Two types of ectopic eruption could be distinguished: a reversible type in which the permanent molar frees itself and an irreversible type in which the permanent molar remains in a locked position. Measurements were made on lateral head films, orthopantomograms, and dental casts. For 104 subjects all variables could be measured. Data was analyzed by discriminant analysis. Children with irreversible ectopic eruption had significantly larger permanent molars and a more pronounced mesial angle of eruption. A tendency toward a shorter maxilla was also found. No significant difference was found between sides with reversible ectopic eruption and sides with normal eruption. From the discriminant analysis between groups and all variables investigated, 90.7 percent of the cases could be correctly classified into groups. This study indicates that sufficient space may be gained for the premolars if the mesial tipping of the first molar is corrected, despite the tendency toward a shorter maxilla and larger than normal permanent molars.     

Association between ectopic eruption of maxillary canines and first molars

The purpose of this study was to elucidate a possible association between ectopic first molar eruption causing root resorption on the distal root of the primary maxillary second molar, and ectopic canine eruption causing root resorption on the permanent maxillary incisors.The subjects consisted of 30 patients, 22 females and eight males in the age range 8.3-15.0 years in whom root resorption of the permanent maxillary lateral and/or central incisor caused by the erupting permanent canine was diagnosed, and clinical and/or radiographic information concerning maxillary first molar eruption existed.It was found that of the 30 patients, seven (23.3 per cent) also had pathological root resorption of the second primary molar caused by ectopic molar eruption.It is suggested that patients with ectopic maxillary first molar eruption leading to pathological root resorption of the maxillary second primary molar are followed closely during the period of premolar and canine eruption, as the ectopic first molar could be an early warning of an increased risk of ectopic canine eruption leading to root resorption of the maxillary permanent incisors.     

Ectopic eruption of the maxillary permanent first molar: the effect of increased mesial angulation on arch length

Fifty-four cases of ectopically erupted maxillary permanent first molars were studied with a method using the measurements obtained from photographs of the study casts. The amount of relative loss of anteroposterior arch length of the right and left sides was shown to correlate with the increased mesial angulation of the maxillary permanent first molar. The bilateral ectopic group has a significantly larger mesial angulation of the permanent first molar on a maxilla with shorter anteroposterior arch length. The relative loss of arch length with ectopic eruption of the permanent first molar limits the use of unilateral appliances for treatment. The use of an appliance with bilateral arch support seems preferable.     

Treatment of children with ectopic eruption of the maxillary first permanent molar by cervical traction

The sequelae of extraction of the second deciduous molar due to irreversible ectopic eruption of the maxillary first permanent molar are mesial tipping of the permanent molar and subsequent space loss. The purpose of this study was to evaluate the effects of early treatment with the Kloehn type of cervical headgear. Forty-six children with ectopic eruption were treated. The mean age at the start of treatment was 8.3 years (range, 6.5 to 9.9 years) and the mean treatment time was 0.8 year (range, 0.5 to 1.0 year). Nineteen variables from orthopantomograms, lateral head films, and dental casts were analyzed by one-way analysis of variance. The registrations were made at the start of treatment, at the end of treatment, and 1 year posttreatment. The treatment resulted in distal tipping of the first permanent molar to a good occlusion in all children. The s-n-ss angle decreased during treatment in all children, and a mean proclination of the maxillary incisors of 3 degrees was registered. Proclination was independent of the type of occlusion and was unchanged 1 year posttreatment. The ss-n-sm angle was also reduced during treatment and was unchanged 1 year posttreatment. The most favorable time for treatment seems to be when the second premolar is close to eruption or erupting at the end of the treatment period. Because of the risk of inhibited sagittal growth of the maxilla with this type of treatment, careful cephalometric evaluation is considered important before the start of treatment.     

Ectopic eruption: presentation of a case with 90 percent rotation of an upper primary second molar

Ectopic eruption of the first permanent molar is a plaguing problem in pedriatric dentistry. This paper reviews the characteristics of ectopic eruption and in the last part reports a case with a 90% rotation of a second primary maxillary molar.     

Enamel defects and ectopic eruption in a child with Usher syndrome and a cochlear implant

BACKGROUND: Usher syndrome is a genetic disorder consisting of progressive loss of vision and hearing. CASE REPORT: The paper describes an 8-year-old girl with Usher syndrome type I who presented with generalized defects of the permanent dentition and ectopic eruption of the right maxillary first permanent molar. A cochlear implant had been fitted for her hearing loss, and the report reviews the implications of this device for dental treatment. The impacted first permanent molar was encouraged to erupt into the correct position by shaving the distal surface of the second primary molar. CONCLUSION: This is the first report to describe in detail an association between Usher syndrome and enamel defects.     

��һ��ĥ����λ�ȳ�����������

第一恒磨牙在萌出过程中过于偏近中可导致第二乳磨牙牙根吸收。第一恒磨牙异位萌出常常造成间隙丧失和牙弓长度减少，严重者可导致第二乳磨牙早失。第一恒磨牙异位萌出分为可逆性和不可逆性，对于不可逆性异位萌出应进行积极的治疗。治疗方法包括主动治疗和被动治疗。前者常用的方法有分牙法以及采用推第一恒磨牙向后的装置；后者通常采用截冠或拔牙的方法。本文对第一恒磨牙异位萌出的临床表现和常用的治疗方法进行了阐述。