改良Nance弓在矫治上颌腭侧埋伏尖牙的作用

目的 探讨改良Nance弓在矫治上颌腭侧埋伏尖牙时矫治力方向设计及支抗设计的作用.方法 7例单侧上颌腭侧埋伏尖牙均采用外科-正畸联合治疗.手术暴露埋伏尖牙牙冠,粘接舌侧扣;戴入改良Nance弓,利用改良Nance弓位于腭侧不锈钢丝上的附钩,先将尖牙冠向后牵引绕过侧切牙的牙根,直到位于正常尖牙间隙的腭侧,如尖牙间隙不足,则粘结上颌托槽,预备尖牙间隙;再采用直丝弓技术将埋伏尖牙向唇侧移动,排齐牙列,调整咬合关系.对治疗后牙齿的松动度、牙髓活力等进行观察.结果 7位埋伏尖牙均被牵引至牙弓的正常位置;牙髓活力测试正常,牙周附着良好.结论 改良Nance弓在矫治上颌腭侧埋伏尖牙时,在矫治力方向设计和支抗控制方面有独特优点和作用.     

改良Nance弓矫治上颌埋伏尖牙对牙周硬组织及牙根的影响

目的:探讨改良Nance弓结合直丝弓矫治上颌埋伏尖牙对牙周硬组织及牙根的影响。方法:利用改良Nance弓矫治8例单侧尖牙埋伏阻生,以对侧自然萌出尖牙作为自身对照。治疗前、后拍摄全景片,测量患侧尖牙移动的距离和角度改变,治疗侧和对侧侧切牙、尖牙、相邻前磨牙的牙槽嵴顶至釉牙骨质界距离及牙根长度,采用SPSS11.0软件包对数据进行配对t检验。结果:埋伏尖牙平均移动距离为18.43mm,全景片上平均移动角度为32.7°,埋伏尖牙侧相邻侧切牙和前磨牙的牙槽嵴高度无降低,牙根无吸收(P0.05)。结论:改良Nance弓结合直丝弓技术是矫治上颌埋伏尖牙的安全、有效方法。     

上颌唇侧水平埋伏阻生尖牙正畸导萌的力学原理分析

目的：分析上颌唇侧埋伏阻生尖牙正畸导萌的力学原理，探讨上颌唇侧埋伏阻生尖牙的矫治力方向设计以及改良Nance弓的作用。方法：采用自行设计的改良Nance弓辅以直丝矫治器，对5例上颌唇侧水平埋伏阻生尖牙进行正畸一外科联合治疗，比较分析了直接牵引和改良Nance弓辅助牵引二种方式的矫治力方向，埋伏牙的移动方式及其力学原理。结果：5例上颌唇侧水平埋伏阻生尖牙顺利萌出至正常位置，尖牙及邻近侧切牙牙髓、牙周健康。力学原理分析显示采用改良Nance弓矫治方法，埋伏牙的移动方式更合理，所需矫治力更轻，支抗负荷更小。结论：矫治上颌唇侧水平埋伏阻生尖牙时，要合理设计矫治力方向，改良Nance弓是一种符合生理力学需要的辅助装置。     

上颌侧切牙与尖牙不完全易位的早期矫治

目的：探讨上颌侧切牙与尖牙不完全易位的早期矫治方法。方法：替牙期上颌侧切牙与尖牙不完全易位病例8例,采用＂2×4＂矫治技术,切开翻瓣术,辅弓牵引尖牙、侧切牙复位。结果：8例上颌侧切牙与尖牙不完全易位者经过8～12个月的治疗,易位的上颌尖牙与侧切牙排列到正常位置。结论：上颌尖牙与侧切牙不完全易位,应早期矫治,以避免上颌侧切牙牙根吸收及完全易位的发生,矫治中的关键是减少尖牙与侧切牙间的移动阻力。     

上颌骨内横位埋伏阻生尖牙的外科一正畸治疗

目的 :上颌骨内横位埋伏阻生尖牙 ,即尖牙冠位于侧切牙根的近中埋伏阻生尖牙 ,两者有重叠 ,由于上颌尖牙及侧切牙恰位于上颌基骨弓的最大转弯处 ,唇侧骨皮质对尖牙冠唇侧的空间限制 ,若按向尖牙缺隙处方向直接牵引 ,将受到侧切牙牙根的阻挡 ,导致侧切牙牙根的吸收 ,被认为是较难矫治的。本文对此类埋伏阻生尖牙诊断及治疗方法进行了探讨。方法 :用螺旋CT三维显示上颌骨内横位埋伏阻生尖牙 ,确定三个方面的情况 :1)埋伏尖牙冠是位侧切牙根的唇侧还是舌侧 ;2 )埋伏尖牙冠与侧切牙牙根间的距离 ;3)侧切牙牙根是否吸收。用直丝弓矫治器进行间隙预备 ,外科翻瓣暴露埋伏尖牙的牙冠 ,粘贴舌侧扣。用改良Nance弓 (末端带钩 )或带垂直外展曲的不锈钢方丝作牵引装置 ,其牵引点与埋伏尖牙冠的连线能避开邻近侧切牙牙根。根据埋伏尖牙冠与侧切牙之间的位置关系 ,先将尖牙冠向外、向后牵引并绕过邻近侧切牙的牙根 ,然后不断改变牵引方向 ,将埋伏尖牙牵引至其正常位置 ,牵引力约 6 0g。结果 :对 5例 6颗上颌横位埋伏阻生尖牙均导萌出后排齐 ,牙髓和牙周情况良好。结论 :根据螺旋CT诊断 ,采用外科一正畸方法及特殊的牵引装置可有效地矫治横位埋伏上颌尖牙。     

上颌尖牙与侧切牙易位的系列矫治

目的探索上颌尖牙与侧切牙易位的矫治方法,以提高临床矫治效果。方法对上颌尖牙与侧切牙易位的11例患者,采用开拓间隙、易位侧切牙人工反让道、易位尖牙远移并控根、舌侧弓丝近中移动侧切牙、交互控根、舌侧固定保持器保持的系列矫治法进行矫治。结果11例患者经系列矫治后均达到了较理想的效果,牙弓排列整齐,易位尖牙与侧切牙牙根平行。结论采用系列矫治法矫治尖牙与侧切牙易位,可有效提高临床矫治效果,缩短矫治时间。     

上颌埋伏尖牙导萌的临床研究

目的探讨上颌埋伏尖牙不同的治疗方法。方法对18例患者的25颗上颌埋伏尖牙进行治疗。首先用直丝弓矫治器拓展埋伏牙的间隙;随后根据患者的年龄、根尖的发育程度、埋伏牙的位置及与邻牙的关系采用不同的导萌方法。9颗上颌埋伏尖牙应用正畸助萌法进行治疗,16颗通过外科翻瓣导萌术进行治疗。结果 25例埋伏牙顺利萌出至正常位置,尖牙及邻近侧切牙牙髓、牙周正常,但正畸助萌法导萌的尖牙牙龈形态更佳。结论正畸助萌法矫治上颌埋伏尖牙效果更佳。     

改良滑动直丝弓托槽的竖沟设计对支抗的影响

目的研究改良滑动直丝弓托槽背板上的竖沟设计在拉尖牙向远中移动的过程中的作用,检验此设计在减小摩擦力节省支抗方面是否有效。方法选用Ⅱ°~Ⅲ°拥挤的AngleⅠ类错患者28例,年龄14~25岁,均拔除四个第一双尖牙,使用杭州西湖巴尔公司生产的改良滑动直丝弓矫治器进行矫治。在拉尖牙向远中移动的过程中,对尖牙采用竖结扎,在尖牙与第一磨牙之间挂弹性橡皮圈,力值为90~100g。在拉尖牙之前及尖牙与第二双尖牙并拢之后,分别进行模型测量和X线头影测量,并进行统计学分析。结果上颌尖牙远中移动的距离与上颌磨牙近中移动距离之比为11.161;下颌尖牙远中移动的距离与下颌磨牙近中移动距离之比为5.941。上下颌切牙均有明显内收。结论改良滑动直丝弓托槽的竖沟设计及尖牙的竖结扎,在拉尖牙向远中移动的过程中减小了尖牙托槽与主弓丝之间的摩擦力,节省了支抗,并符合差动力的原理。改良滑动直丝弓矫治器的使用可为错畸形的矫治提供强支抗,从而省去了使用口外弓等其它增强支抗的方法,使滑动直丝弓矫治器的使用更加简便。     

直丝弓排齐与整平阶段切牙唇倾和支抗的研究

目的 直丝弓拔牙矫治技术在排齐与整平阶段牙齿易出现切牙唇倾,临床上常采取尖牙向后８字结扎和末端弓丝回弯的措施来预防,对其效果进行实验研究。方法 ２６例拔除４颗第一双尖牙的病例,使用国产Ｒｏｔｈ数据直丝弓矫治器进行矫治,采取上述措施并且上颌加横腭杆,进行Ｘ片头影测量和统计分析。结果 上切牙牙轴无明显变化,下切牙直立,切牙水平位置没有明显移动;上下磨牙平均约前移１ｍｍ,但是相对于Ｂｅｇｇ和方丝弓矫治器     

预置支点介导下的上颌近远中阻生尖牙的矫治

目的 探讨预置支点在矫治上颌水平阻生尖牙的作用.方法 水平埋伏阻生上颌尖牙5例,均位于邻牙根方.用直丝弓矫治器进行间隙预备,外科开窗暴露埋伏尖牙的牙冠,将预置支点置于牙颈部,进行正畸牵引,曲面断层片观察邻牙牙根吸收情况.结果 水平阻生尖牙以预置支点为转动中心而移动至正常位置,牙髓和牙周情况良好,邻牙牙根无吸收现象.结论 预置支点水平阻生上颌尖牙的转动中心,对正畸临床治疗有指导意义.     

埋伏上尖牙与侧切牙发生不完全易位的矫治方法研究

目的 探讨埋伏阻生上尖牙与侧切牙发生不完全易位后的导萌方法,将易位的尖牙牵引至正常位置,以达到美观效果,行使正常功能.方法 选择不完全易位的单侧埋伏阻生上尖牙患者12例（男6例,女6例）,年龄11.5～21.0岁,平均14.5岁,其中尖牙偏腭侧阻生7例,偏颊侧阻生5例.外科手术暴露埋伏牙,应用固定矫治技术,调整牵引方向将埋伏牙牵引至正常位置.结果 易位的尖牙均与侧切牙发生位置交换,尖牙移至正常位置,且具有良好的冠根方向和咬合关系,尖牙及侧切牙均无明显根吸收.平均疗程19个月.结论 将不完全易位的埋伏尖牙牵引入正常位置的难点在于易位埋伏的尖牙翻越相邻侧切牙牙根时,二者不相互阻挡.解决此难点的关键是精确判断尖牙牙冠与侧切牙牙根的位置关系,适时调整牵引方向.     

上颌中切牙与尖牙同时阻生的临床特征分析

目的分析上颌中切牙与同侧尖牙同时阻生病例的临床特征。方法选择上颌中切牙与同侧尖牙同时阻生病例21例,分析上颌中切牙阻生类型与尖牙阻生情况,测量阻生侧及对侧侧切牙发育或萌出异常情况。结果与中切牙阻生同时发生的尖牙76.2%为唇侧阻生,其中完全易位与不完全易位占唇侧阻生尖牙的68.8%,尖牙唇侧阻生病例中侧切牙根远中倾斜和伴牙冠近中倾斜者占87.5%,尖牙唇侧或腭侧阻生病例中,出现锥形或过小等畸形侧切牙的比例分别为31.25%和40.00%。上颌中切牙与尖牙不同阻生类型患者,前牙反牙合比例都超过40%,且多为牙型反牙合。结论与中切牙阻生同时发生的尖牙阻生多为唇侧阻生,与中切牙阻生类型无关,与侧切牙根远中倾斜高度相关,尖牙完全易位与过小或锥形等畸形侧切牙有关。     

Treatment of maxillary canine transposition

Transposition of maxillary teeth is an eruptive disturbance occurring in approximately 1 of every 300 orthodontic patients. Such cases are frequently very challenging in terms of treatment planning and orthodontic management. The canine is one of the most commonly transposed teeth, ectopically positioned with either the lateral incisor or the first premolar. This case report illustrates unique orthodontic treatment, describes treatment procedures, and presents the final outcome of bilateral maxillary canine-lateral incisor complete transpositions in which the involved teeth were moved to their clinically normal position in the dental arch without extracting premolars.     

Unilaterally impacted maxillary central incisor and canine with ipsilateral transposed canine-lateral incisor

Concurrent impaction and transposition of maxillary anterior teeth is uncommon and poses a challenge for dentists. Early diagnosis and management of eruption disturbances benefits esthetic and functional outcomes. This article describes the treatment of a teenager who had impactions of the left maxillary central incisor and canine as well as ipsilateral canine-lateral incisor transposition. Treatment alternatives and effective orthodontic techniques are delineated. To optimize the treatment results, the impacted maxillary canine was surgically exposed and orthodontically distalized with an innovative cantilever. Subsequently, the deeply impacted maxillary central incisor was uncovered and orthodontically mesialized into the arch. Finally, the displaced maxillary lateral incisor was brought into its normal position. The combined surgical-orthodontic approach resolved a difficult clinical issue and avoided additional restorations. An esthetic, functional outcome was achieved and satisfied the patient.     

单侧上颌尖牙阻生对牙颌三维结构的影响

目的: 采用锥形束CT（CBCT）研究单侧尖牙阻生病例牙颌的三维结构特征,评估发生上颌尖牙阻生的相关风险因素,为正畸临床早期干预提供依据。方法: 选取30例单侧上颌尖牙阻生患者的CBCT,利用Romexis软件进行三维重建,测量、比较两侧牙颌三维结构特征指标,采用SPSS17.0软件包进行配对t检验和相关数据的回归分析。结果: 阻生侧尖牙和侧切牙倾斜度明显增大,尖牙牙冠更向近中、侧切牙向远中倾斜（P<0.001）;阻生侧尖牙体积更大、侧切牙体积更小（P<0.05）,当尖牙体积增大或侧切牙体积减小时,上颌尖牙的阻生概率增加;阻生侧牙弓弧形长度更短,牙弓宽度在尖牙区和前磨牙区更短（P<0.001）,而宽度在磨牙区无显著差异（P>0.05）,两侧牙弓长度在尖牙区、前磨牙区和磨牙区无显著差异（P>0.05）。结论: 上颌尖牙阻生伴随或导致同侧牙及牙槽骨三维方向发育异常,上颌尖牙阻生的严重程度与周围牙颌结构异常密切相关,提示上颌尖牙阻生可以早期预判、诊断,且可以实施有效的早期干预。     

Maxillary canine impactions related to impacted central incisors: two case reports

AIM: The purpose of this case report is to describe the combined surgical and orthodontic treatment of two cases with an impacted maxillary central incisor and canine in the same quadrant and to discuss the causal relationship between them. BACKGROUND: The most common causes of canine impactions are usually the result of one or more factors such as a long path of eruption, tooth size-arch length discrepancies, abnormal position of the tooth bud, prolonged retention or early loss of the deciduous canine, trauma, the presence of an alveolar cleft, ankylosis, cystic or neoplastic formation, dilaceration of the root, supernumerary teeth, and odontomas. Although impaction of the maxillary central incisor is almost as prevalent as impacted canines its etiology is different. The principal factors involved in causing the anomaly are supernumerary teeth, odontomas, and trauma. REPORTS: Case #1: A 10.5-year-old girl in the early mixed dentition stage presented with a chief complaint of the appearance of her anterior teeth. She had a Class I skeletal pattern and a history of trauma to the maxillary central incisors at age five with premature exfoliation. Radiographs revealed an impacted upper right central incisor in the region of the nasal floor, delayed eruption of the maxillary permanent central incisor, and the adjacent lateral incisor was inclined toward the edentulous space. Treatment was done in two stages consisting of surgical exposure and traction of the impacted central incisor and fixed orthodontic treatment. Case #2: An 11.5-year-old girl presented for orthodontic treatment with the chief complaint of an unerupted tooth and the appearance of her upper anterior teeth. She was in the late mixed dentition period with a Class III skeletal pattern along with an anterior cross-bite with some maxillary transverse deficiency. The maxillary right canine and central incisor were absent, but the maxillary right deciduous canine was still present. Treatment included arch expansion followed by surgical exposure and traction of the impacted teeth and fixed orthodontic treatment. SUMMARY: This case report provides some evidence of a significant environmental influence of an impacted maxillary central incisor on the path of eruption of the ipsilateral maxillary canine. When an impacted maxillary central incisor exists, the maxillary lateral incisor's root might be positioned distally into the path of eruption of the maxillary canine preventing its normal eruption. Ongoing assessment and early intervention might help to prevent such adverse situations from occurring.     

Endodontic treatment of a maxillary lateral incisor presenting dens invaginatus and transposition to the region of the canine--case report.

Endodontic treatment was performed in a maxillary lateral incisor presenting two different types of anomalies: dens invaginatus and transposition to the region of the canine. The two transposed teeth were subsequently restored with light-cured composite, bringing dental esthetics to normal in a single session.