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        上頜低位尖牙矯治的應(yīng)力釋放

        2018-09-21 11:08:02李畢超任利玲
        中國美容醫(yī)學(xué) 2018年6期

        李畢超 任利玲

        [摘要]上頜尖牙唇側(cè)異位萌出在臨床上較為常見,其病因可能是因牙列擁擠導(dǎo)致。由于唇側(cè)異位萌出的尖牙低位程度不一,傳統(tǒng)固定矯治技術(shù)認(rèn)為當(dāng)尖牙低位嚴(yán)重時,矯治弓絲不可直接將其納入,否則會導(dǎo)致鄰牙壓低局部開牙合,甚至出現(xiàn)牙合平面的切斜等。Damon系統(tǒng)則建議矯治早期盡量將錯位牙納入全牙列矯治,目前僅有文獻(xiàn)報道尖牙異位的平均高度為(10.5±3.8)mm,而無唇側(cè)異位萌出尖牙平均高度的研究,萌出的尖牙低位程度不一,能否將其直接納入全牙列矯治,需要謹(jǐn)慎對待。本文綜述了將低位尖牙納入矯治系統(tǒng)后,尖牙及鄰牙的應(yīng)力釋放情況,以期為臨床矯治低位尖牙提供指導(dǎo)。

        [關(guān)鍵詞]異位尖牙;低位;應(yīng)力釋放;Damon系統(tǒng);低摩擦

        [中圖分類號]R783.5 [文獻(xiàn)標(biāo)志碼]A [文章編號]1008-6455(2018)06-0152-03

        Abstract: It is more common in patients with maxillaryapically displaced canine caused by crowded dentition in literatures.The anterior openbite which was the result of the intrusion of lateral incisor and first premolar would occur when engaged the severe infraversion of canine in conventional stainless steel ligature system. Damon system recommended thatthe malposed teeth were included in the orthodonticsas early as possible. Although there are a few reports that the mean values for the distance of the displaced maxillary canines from the occlusal plane were (10.5±3.8)mm,it is still unclear about the infraversion of etrupted canine.The average height of the ectopic canine from the occlusal plane were varied,whether it can level a vertically displaced canine using a continuous arch wire directly, the stress release of the orthodontic systemwith apical canine will be the main content of this review.

        Key words: displaced canine; infraversion; stress release; damon system; low friction

        尖牙異位是指尖牙牙胚偏離正常萌出道而向唇頰側(cè)(buccally displaced canine,BDC)或腭側(cè)異位(palatally displaced canine,PDC),是牙列發(fā)育過程中一種常見的異位,??蓪?dǎo)致尖牙阻生或異位萌出[1-3]。異位萌出(ectopic eruption)是指恒牙在萌出過程中未在牙列的正常位置萌出[4]。低位(infraversion),又稱牙牙合下錯位,指牙齒未萌出至牙合平面而低于牙合平面[5-6]。

        1 尖牙低位的病因?qū)W

        尖牙異位與尖牙發(fā)育、萌出延遲有無因果關(guān)系尚不十分明確,Becke等[7-8]認(rèn)為尖牙腭側(cè)異位(PDC)患者常伴有尖牙發(fā)育遲緩,而尖牙唇側(cè)異位(BDC)則與之無關(guān);Ingrid等學(xué)者[9]則認(rèn)為尖牙唇、腭向異位均可能伴有尖牙發(fā)育或萌出延遲。雖然Lindauer等[10]定義尖牙阻生為未萌出尖牙牙根已發(fā)育完全者或?qū)?cè)同名牙已萌出至少6個月且牙根發(fā)育完全者,但目前尚無界定尖牙異位與尖牙阻生的明確定義,對于適齡兒童尖牙尚未萌出者,大多很難準(zhǔn)確地判斷其是與尖牙異位相關(guān)的尖牙發(fā)育或萌出延遲還是尖牙阻生,而兩種診斷結(jié)果所采取的治療方法也截然不同。

        流行病學(xué)研究表明:尖牙阻生發(fā)病率僅次于第三磨牙約為2%[11-13]。其較高的發(fā)病率除與遺傳有關(guān)外,還與尖牙萌出時間晚,萌出道長(22mm)且扭曲相關(guān)[14]。上頜尖牙唇、腭側(cè)異位的原因有所不同,腭側(cè)異位常和患側(cè)側(cè)切牙形態(tài)異常有關(guān),其病因?qū)W解釋較為流行的是誘導(dǎo)學(xué)說(Guidance theory)和遺傳學(xué)說(Genetic theory)。誘導(dǎo)學(xué)說認(rèn)為側(cè)切牙牙根的遠(yuǎn)中面為尖牙的萌出提供引導(dǎo)作用,側(cè)切牙缺失或牙根異常使尖牙萌出失去引導(dǎo)而偏離正常萌出道致其異位阻生;遺傳學(xué)說則認(rèn)為尖牙異位是由遺傳因素決定的,40%的患者并發(fā)有第三磨牙發(fā)育不全及牙列其他異常,如側(cè)切牙先天缺失或發(fā)育不全等。唇側(cè)異位阻生常與牙列擁擠相關(guān),如乳恒牙替換障礙,乳尖牙早失等,發(fā)病率較腭側(cè)低[14-19]。一些學(xué)者[20-21]認(rèn)為唇、腭側(cè)異位阻生發(fā)生率和病因差異不大,因為多數(shù)尖牙唇側(cè)異位阻生可自行萌出而使得發(fā)病率降低。臨床常見尖牙唇側(cè)異位萌出由于牙列擁擠而無足夠空間萌出不得不唇側(cè)低位生長。異位尖牙距離牙合平面高度平均為(10.5±3.8)mm[22],但尚無文獻(xiàn)報道已萌出的低位尖牙距牙合平面平均高度。而Damon系統(tǒng)因其良好的輕力低摩擦作用,建議矯治早期即將不同程度的錯位牙納入矯治[23-24]。

        2 上頜低位尖牙矯治的應(yīng)力釋放研究

        2.1 不同矯治系統(tǒng)對低位尖牙及鄰牙三維方向所產(chǎn)生的矯治力的研究:固定矯治系統(tǒng)弓絲對牙齒產(chǎn)生矯治力的大小主要與弓絲、托槽及結(jié)扎方式之間相互作用所產(chǎn)生的滑動阻力大小有關(guān),而滑動阻力主要包括經(jīng)典摩擦力、彈性約束力和刻痕阻力[25-26]。低位尖牙距牙合平面越高,弓絲形變產(chǎn)生的作用力越大,弓絲與托槽成角越大,彈性約束力也隨之增大,在1mm高度時,弓絲與托槽夾角約7°,彈性約束力占滑動阻力93%;3mm高度為20°,彈性約束力占97%[24],可見滑動阻力構(gòu)成中彈性約束力起主導(dǎo)作用。

        Baccetti等[27-28]研究了自鎖托槽、傳統(tǒng)托槽與超彈鎳鈦絲分別在1.5mm、3mm、4.5mm、6mm高度時尖牙的受力情況發(fā)現(xiàn),無論自鎖還是傳統(tǒng)托槽系統(tǒng),尖牙受到的牙合向力經(jīng)歷由小到大又逐漸變小的過程,在3~4mm高度時自鎖托槽系統(tǒng)尖牙所受牙合向力達(dá)到峰值,其后隨著尖牙低位越嚴(yán)重,其所受牙合向力越小。傳統(tǒng)托槽在4.5、6mm處所受牙合向力為0g,這是因為隨著尖牙低位程度越來越大,側(cè)切牙遠(yuǎn)中、第一前磨牙近中所受的彈性約束力也越來越大[26,29]。Badawi等[30]用Orthodontic Simulator(OSIM)儀器對弓絲進(jìn)行0~4mm的加載與卸載試驗,發(fā)現(xiàn)加載與卸載過程中尖牙受力不同,加載過程牙合向力0~4mm逐漸增大,卸載過程1.1~3.4mm高度時存在應(yīng)力釋放平臺期,正畸治療中納入低位尖牙可認(rèn)為是弓絲卸載過程。卸載過程中尖牙受力情況,牙合齦向:主要表現(xiàn)為牙合向力,并存在平臺期;近遠(yuǎn)中向:主要為近中向力;唇舌向:卸載初期為舌向力之后迅速表現(xiàn)為唇向力。Badawi等[30]研究認(rèn)為在矯正低位尖牙過程中,側(cè)切牙和第一前磨牙的受力情況為:牙合齦向:側(cè)切牙與第一前磨牙均受到齦向壓低力作用,自鎖托槽組存在平臺期,而彈性結(jié)扎組的齦向壓低力隨尖牙高度不同趨向線性變化;近遠(yuǎn)中向:側(cè)切牙遠(yuǎn)中向力,第一前磨牙近中向力;唇舌向:側(cè)切牙唇向力,第一前磨牙自鎖組先唇向后舌向,彈性結(jié)扎組舌向力。

        2.2 低摩擦與傳統(tǒng)托槽系統(tǒng):被動自鎖相對于傳統(tǒng)彈性結(jié)扎矯治系統(tǒng)對尖牙低位所產(chǎn)生的矯治力系統(tǒng)更為精確,研究發(fā)現(xiàn)使用自鎖矯治系統(tǒng)矯治弓絲進(jìn)入低位尖牙受到的伸長力接近垂直向,產(chǎn)生較小的副作用力和力矩[31]。對于尖牙低位程度較輕者,傳統(tǒng)托槽和自鎖托槽差別不大,對尖牙均能產(chǎn)生適當(dāng)?shù)纳扉L力,但當(dāng)尖牙低位大于3mm時,被動自鎖托槽仍能釋放適宜的矯治力,而傳統(tǒng)彈性結(jié)扎在尖牙低位達(dá)到4.5mm高度時對尖牙產(chǎn)生的伸長力為0g??梢妼τ诩庋赖臀幌鄬^嚴(yán)重者,被動自鎖矯治系統(tǒng)滑動阻力更小,產(chǎn)生更為有效的矯治力,且在一定范圍內(nèi)能維持一定的力值水平(卸載平臺期)[27-28,30-32]。

        2.3 不同矯治弓絲對低位尖牙產(chǎn)生的矯治力研究:低位尖牙牽引力量一般應(yīng)小于100g[6]。多篇體外機(jī)械力學(xué)研究表明[33-34]:在1.5mm高度時0.012、0.014inch鎳鈦絲在被動自鎖組(自鎖組)與傳統(tǒng)彈性結(jié)扎組(傳統(tǒng)組)對尖牙產(chǎn)生伸長力的大小差別不大,分別為52.5~74g、103.4~111.6g;3mm高度時0.012inch鎳鈦絲自鎖組為78.2~96.3g而傳統(tǒng)組約為52g,0.014inch鎳鈦絲自鎖組為110.6~125.8g傳統(tǒng)組約53g;4.5~6mm高度時0.012inch、0.014inch鎳鈦絲自鎖組41.2~85.6g、96.1~122.4g,而傳統(tǒng)組均為0g。但由于力學(xué)實驗不可能在口腔內(nèi)完成,上述體外力學(xué)研究排除了軟組織、牙的整體和傾斜移動、牙與牙的鄰面接觸、口腔濕度、唇舌壓力等影響矯治力大小的因素。

        不銹鋼絲在一定形變范圍內(nèi)近似線彈性體,在該形變范圍內(nèi)可根據(jù)形變值估計應(yīng)力大小。與之不同的是,鎳鈦絲在受到機(jī)械壓力和溫度變化的影響時可發(fā)生同素異構(gòu)轉(zhuǎn)變,使得其應(yīng)力釋放難以預(yù)測。鎳鈦絲可以在一定形變范圍內(nèi)保持力值大小基本不變(上述卸載平臺期的原因),而某些情況下形變產(chǎn)生的應(yīng)力遠(yuǎn)大于預(yù)測值。Wilkinson等[35]比較了五家制造商生產(chǎn)的48種商業(yè)用鎳鈦絲,結(jié)果表明大部分正畸鎳鈦絲沒有或僅有一點超彈性。另外,熱激活鎳鈦絲在低摩擦矯治系統(tǒng)有很好的輕力優(yōu)勢,但對于傳統(tǒng)矯治器而言其輕力因無法克服矯治系統(tǒng)滑動阻力而無法發(fā)揮作用?;谏鲜鲈?,不同弓絲形變產(chǎn)生的力值大小不同,不同制造商生產(chǎn)的鎳鈦絲超彈性能有很大差別,不同托槽弓絲結(jié)扎系統(tǒng)產(chǎn)生的力系統(tǒng)也明顯不同,對于低位尖牙除了其本身低位程度以外,弓絲的選擇也應(yīng)慎重。

        3 小結(jié)

        綜上所述,因為彈性約束力的存在,不同矯治系統(tǒng)對尖牙產(chǎn)生的伸長力經(jīng)歷由小到大再變小的過程;被動自鎖系統(tǒng)存在卸載平臺期,而傳統(tǒng)彈性結(jié)扎托槽系統(tǒng)趨向線性關(guān)系。由于口腔環(huán)境的特殊性,大多實驗研究主要為體外進(jìn)行的機(jī)械力學(xué)試驗和電腦模擬(如三維有限元分析)等,多數(shù)試驗設(shè)計多為局部的(五顆托槽)、一維的(垂直向),簡化了很多解剖結(jié)構(gòu)如牙周膜等,且尖牙自身存在三維方向角度,如常見的近中傾斜,這些因素都會影響矯治系統(tǒng)的應(yīng)力釋放。另外,矯治低位尖牙過程中,除了應(yīng)關(guān)注矯治系統(tǒng)對低位尖牙產(chǎn)生的伸長力大小外,還應(yīng)考慮矯治系統(tǒng)對鄰牙三維方向上的副作用力,如何權(quán)衡兩者,還需要臨床隨機(jī)對照試驗結(jié)論的指導(dǎo)。

        [參考文獻(xiàn)]

        [1]Baccetti T.Risk indicators and interceptive treatment alternatives for palatally displaced canines [J].Sem Orthod,2010,16(3):186-192.

        [2]Smailiene D,Sidlauskas A,Lopatiene K,et al.Factors affecting self-eruption of displaced permanent maxillary canines [J].Medicina (Kaunas, Lithuania),2011,47(3): 163-169.

        [3]Baccetti T,Leonardi M, Giuntini V. Distally displaced premolars: A dental anomaly associated with palatally displaced canines [J].Am J Orthod Dentofacial Orthop,2010,38(3): 318-322.

        [4]葛立宏.兒童口腔醫(yī)學(xué)[M].4版.北京:人民衛(wèi)生出版社,2012:90-93.

        [5]English J,Peltomaki T,Phamlitschel K. Mosby's orthodontic review [M].Mosby Elsevier,2009:29-30.

        [6]陳揚熙.口腔正畸學(xué)—基礎(chǔ)、技術(shù)與臨床[M].北京:人民衛(wèi)生出版社,2012:580-582.

        [7]Becker A,Chaushu S. Dental age in maxillary canine ectopia [J].Am J Orthod Dentofacial Orthop,2000,117(6):657-662.

        [8]Naser DH, Abu Alhaija ES,Al-Khateeb SN. Dental age assessment in patients with maxillary canine displacement [J]. Am J Orthod Dentofacial Orthop,2011,140(6): 848-855.

        [9] Rozylo-Kalinowska I, Kolasa-Raczka A, Kalinowski P. Dental age in patients with impacted maxillary canines related to the position of the impacted teeth [J]. Eur J Orthod,2011,33(5):492-497.

        [10]Lindauer SJ,Rubenstein LK,Hang WM,et al.Canine impaction identified early with panoramic radiographs [J].J Am Dent Assoc,1992,123(3):91-92,95-97.

        [11]Sajnani AK. Permanent maxillary canines - review of eruption pattern and local etiological factors leading to impaction [J]. J Investig Clin Dent,2015,6(1):1-7.

        [12]Paschos E, Huth KC, Fassler H, et al.Investigation of maxillary tooth sizes in patients with palatal canine displacement [J].J Orofac Orthop,2005,66(4):288-298.

        [13]Liuk IW,Olive RJ,Griffin M,et al. Maxillary lateral incisor morphology and palatally displaced canines: a case-controlled cone-beam volumetric tomography study[J]. Am J Orthod Dentofacial Orthop,2013,143(4): 522-526.

        [14]Becker A, Chaushu S. Etiology of maxillary canine impaction: a review [J]. Am J Orthod Dentofacial Orthop,2015,148(4): 557-567.

        [15]Peck S,Peck L, Kataja M. Prevalence of tooth agenesis and peg-shaped maxillary lateral incisor associated with palatally displaced canine (PDC) anomaly [J]. Am J Orthod Dentofacial Orthop,1996,110(4): 441-443.

        [16]Amini F,Hamedi S,Haji Ghadimi M,et al.Associations between occlusion, jaw relationships, craniofacial dimensions and the occurrence of palatally-displaced canines [J].Int Orthod,2017,15(1):69-81.

        [17]Alqerban A,Storms AS,Voet M,et al.Early prediction of maxillary canine impaction [J]. Dent Maxillofac Radiol,2016,45(3):20150232.

        [18]Bedoya MM,Park JH. A review of the diagnosis and management of impacted maxillary canines [J]. J Am Dent Assoc,2009,140(12):1485-1493.

        [19]Rutledge MS,Hartsfield Jr JK.Genetic factors in the etiology of palatally displaced canines [J].Sem Orthod,2010,16(3):165-171.

        [20]Sajnani AK,King NM.Dental anomalies associated with buccally and palatally-impacted maxillary canines [J].J Investig Clin Dent,2014,5(3):208-213.

        [21]Bishara SE,Ortho D.Impacted maxillary canines: A review [J].Am J Orthod Dentofacial Orthop,1992,101(2):159-171.

        [22]Grande T,Stolze A,Goldbecher H,et al.The displaced maxillary canine--a retrospective study [J].J Orofac Orthop,2006,67(6):441-449.

        [23]林錦榮.正畸臨床創(chuàng)新 [M].上海:上海世界圖書出版公司,2014:22-25.

        [24]Kim SJ,Kwon YH,Hwang CJ.Biomechanical characteristics of self-ligating brackets in a vertically displaced canine model: a finite element analysis [J]. Orthod Craniofac Res,2016,19(2):102-113.

        [25]Kusy RP.Ongoing innovations in biomechanics and materials for the new millennium [J].Angle Orthod,2000,70(5):366-376.

        [26]Kusy RP,Whitley JQ.Influence of archwire and bracket dimensions on sliding mechanics: derivations and determinations of the critical contact angles for binding [J].Eur J Orthod,1999,21(2):199-208.

        [27]Baccetti T,F(xiàn)ranchi L,Camporesi M,et al.Orthodontic forces released by low-friction versus conventional systems during alignment of apically or buccally malposed teeth [J].Eur J Orthod,2011,33(1):50-54.

        [28]Baccetti T,F(xiàn)ranchi L,Camporesi M,et al.Forces produced by different nonconventional bracket or ligature systems during alignment of apically displaced teeth [J]. Angle Orthod,2009,79(3):533-539.

        [29]Kusy RP.Influence on binding of third-order torque to second-order angulation [J]. Am J Orthod Dentofacial Orthop,2004,125(6):726-732.

        [30]Badawi HM,Toogood RW,Carey JP,et al.Three-dimensional orthodontic force measurements [J]. Am J Orthod Dentofacial Orthop,2009,136(4): 518-528.

        [31]Fok J,Toogood RW,Badawi H,et al. Analysis of maxillary arch force/couple systems for a simulated high canine malocclusion: Part 1. Passive ligation [J]. Angle Orthod,2011,81(6):953-959.

        [32]Baccetti T,F(xiàn)ranchi L.Friction produced by types of elastomeric ligatures in treatment mechanics with the preadjusted appliance [J].Angle Orthod,2006, 76(2):211-216.

        [33]Franchi L,Baccetti T,Camporesi M,et al.Forces released during sliding mechanics with passive self-ligating brackets or nonconventional elastomeric ligatures [J]. Am J Orthod Dentofacial Orthop,2008,133(1):87-90.

        [34]Major PW,Toogood RW,Badawi HM,et al.Effect of wire size on maxillary arch force/couple systems for a simulated high canine malocclusion [J].J Orthod,2014,41(4):285-291.

        [35]Wilkinson PD,Dysart PS,Hood JA,et al.Load-deflection characteristics of superelastic and thermal nickel-titanium wires [J]. Am J Orthod Dentofacial Orthop,2002,121(5):483-495.

        [收稿日期]2018-04-15 [修回日期]2018-05-30

        編輯/李陽利

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