摘要:ProTaper銼是一種鎳鈦根管預(yù)備器械,它采用可變多錐度的刃部,凸三角形的橫截面設(shè)計(jì),使該器械具有更高的切削能力、彈性和理想的成形根管能力,特別適于在彎曲根管的預(yù)備,但在重度彎曲根管的成形中,如\"S\"形根管,尚存在一些不足之處。
關(guān)鍵詞:ProTaper銼;根管成形;彎曲根管
中圖分類(lèi)號(hào):R781.5文獻(xiàn)表示碼:A
The ProTaper File in the \"S\" - Shaped Root Research Status in the Tube Forming Effect
WANG Yan-ping1,LIU An-dong2
(1.Department of Stomatology, The Second People's Hospital of Hefei City, Hefei 230011, Anhui,China;2.Department of Stomatology,The Second people's Hospital of Anhui Province, Hefei 230011,Anhui,China)
Abstract:ProTaper file is a nickel-titanium root canal preparation equipment,which uses the variable multi-tapered blades,convex triangular cross-sectional design,so that the device has higher cutting capacity, flexibility and the ideal forming root canal ability,especially suitable for in bending root canal preparation,but in severe bending tube forming,such as \"S\"-shaped root canal,and there are still some shortcomings.
Key words:ProTaper file;Root canal shaping;Curved root canal
根管預(yù)備是決定根管治療成敗的關(guān)鍵因素之一,根管預(yù)備是根管治療中復(fù)雜和主要的步驟,它有兩個(gè)目的:根管清理和根管成形,通過(guò)器械預(yù)備和化學(xué)預(yù)備相結(jié)合的方法進(jìn)行[1]。傳統(tǒng)的手用不銹鋼器械由于其固有的硬度和剛度,易造成根管變形、根尖偏移、臺(tái)階形成甚至穿孔,而且預(yù)備效率低[2]。隨著鎳鈦合金的引入,根管預(yù)備器械有了快速的發(fā)展。鎳鈦合金具有記憶性,其彈性是不銹鋼的的2~3倍,鎳鈦器械已證實(shí)在保持根管初始解剖形態(tài)上比不銹鋼器械優(yōu)越得多[3]。
近年來(lái),鎳鈦器械的設(shè)計(jì)向大錐度、不同橫截面發(fā)展,更適宜于彎曲根管的預(yù)備[4]。ProTaper銼就是其中的一種,因其具有獨(dú)特的凸三角形橫截面和可變錐度的設(shè)計(jì),在根管預(yù)備中能保持根管的解剖初形[5] 。但有研究表明,在預(yù)備嚴(yán)重彎曲的根管,如\"S\"形根管時(shí),會(huì)產(chǎn)生較大的根管偏移[6]。為了克服這個(gè)不足之處,國(guó)內(nèi)外學(xué)者做了大量的研究,如與其他錐度鎳鈦銼聯(lián)合使用、改進(jìn)預(yù)備方法等。
很多學(xué)者研究\"S\"形根管都是用透明樹(shù)脂模擬根管[2,4,5,8,9],因此本文就Protaper銼在此種類(lèi)型根管中的預(yù)備后根管全長(zhǎng)根管內(nèi)外側(cè)壁去除樹(shù)脂量與預(yù)備后根管寬度、預(yù)備后根管缺陷及器械變形和(或)折斷等情況作一綜述。
1關(guān)于ProTaper銼
Protaper的套裝有三根預(yù)形銼和三根修整銼,有六根器械[7]。SX:輔助成型銼,其特點(diǎn)是無(wú)色環(huán)。預(yù)形銼的尖部至端部逐步增粗,目的為了特定的區(qū)域。S1和S2手柄上紫色和白色的色環(huán),S1預(yù)備根管冠1/3,S2預(yù)備根管中1/3。修形銼(F1,F(xiàn)2,F(xiàn)3):它們分別有黃色,紅色和藍(lán)色的色環(huán)。修形銼通常用于根尖1/3的預(yù)備。通常,一個(gè)根管的根尖1/3的預(yù)備只需要一根成形銼。ProTaper推薦使用冠根向深入法。
2 ProTaper的成形能力
2.1根管內(nèi)外側(cè)壁去除樹(shù)脂量與預(yù)備后根管寬度 Ersev H[8]的研究顯示,在模擬\"S\"形根管中,與K3和RaCe相比較,Protaper銼更明顯的擴(kuò)大了根管,特別是在彎曲部分的內(nèi)側(cè)壁,有拉直根管的趨勢(shì)。Lan Zhang[9]的研究指出,單獨(dú)使用Protaper銼時(shí),Protaper成形銼去除樹(shù)脂量在相同型號(hào)的器械中最少,Protaper修形銼對(duì)根管彎曲內(nèi)側(cè)和根尖外側(cè)最大,從S2到F1和F2到F3間差異明顯,而Protaper銼合并Hero642預(yù)備完成后,根管無(wú)明顯偏移,錐度良好。Huang Ding-ming[10]甚至提出,在根尖部,Protaper成形銼對(duì)根管形態(tài)預(yù)備量甚至和K銼相同。
上述的研究都表明,Protaper成形銼有良好的維持根管走向的能力,使用ProTaper修形銼是根管拉直的主要原因,且導(dǎo)致預(yù)備后的根管從根管口到根尖孔寬度變化不規(guī)則,在距根尖1 mm處寬度小于根尖孔處。這是因?yàn)槌尚武S漸增錐度的設(shè)計(jì),使其刃部尖端直徑和錐度小,彈性好,而刃部末端錐度和直徑增大,敞開(kāi)根管口上段。而修形銼對(duì)根管形態(tài)改變明顯。Protaper的修形銼采用大錐度的設(shè)計(jì),有研究報(bào)道[11],其中的F3(錐度9%),已相當(dāng)與4%錐度的45#~50#。因此剛性增大,在彎曲部分存在較大的趨于恢復(fù)原型的側(cè)向力,過(guò)多的切削彎曲部分的內(nèi)側(cè)和根尖外側(cè),造成彎曲部分的拉直。如果只用成形銼預(yù)備根管的冠2/3,而用一些小錐度的銼如鎳鈦K銼、Hero642等預(yù)備根1/3,則可取的良好的成形效果。
2.2預(yù)備后根管缺陷情況 在模擬\"S\"形根管中,與K3和RaCe相比,在根尖部,盡管用很小的力,在用過(guò)F2后,ProTaper銼仍有產(chǎn)生根尖歧岥或臺(tái)階的趨勢(shì)[12]。Calberson FL[13]提出,在彎曲根管中,在用過(guò)F2和F3后,根尖也產(chǎn)生了歧岥。有的研究還指出,Protaper銼在根尖部的偏移量竟然與不銹鋼K銼相同[10]。出現(xiàn)以上情況的原因,最主要的還是因?yàn)樾扌武S的大錐度設(shè)計(jì),導(dǎo)致其刃部的剛性增大,從而產(chǎn)生較大的恢復(fù)力,導(dǎo)致了根尖部各種各樣的缺陷的產(chǎn)生。因此,Schaferetal通過(guò)研究鎳鈦銼的錐度和其彈性之間的關(guān)系得出,在彎曲根管中,錐度大的器械就不應(yīng)該用來(lái)預(yù)備根管尖端[14]。但也有研究表明,0.06錐度的銼也可以預(yù)備出理想的根管形狀而不產(chǎn)生明顯的缺陷,如歧岥、臺(tái)階等,只要在用0.06錐度的器械前,用一些小錐度的銼來(lái)預(yù)備就可以了[15]。但總體來(lái)說(shuō),在一些嚴(yán)重彎曲的根管中,如果把ProTaper銼和一些錐度小、彈性好的器械聯(lián)合使用,會(huì)取得較好的根管成形效果[8]。
2.3器械變形和(或)折斷情況 器械的抗機(jī)械分離對(duì)于根管預(yù)備極為重要。鎳鈦器械的機(jī)械分離的機(jī)理有扭曲機(jī)械分離和彎曲疲勞機(jī)械分離2種[16]。器械折斷是器械在彎曲根管中反復(fù)彎曲伸直引起的。
雖然ProTaper在刃部有形態(tài)改變,器械所受轉(zhuǎn)矩減小,且Berutti等[17]使用有限元分析的數(shù)學(xué)模式分析也得出,與其他的鎳鈦銼相比,ProTaper的凸三角形橫截面設(shè)計(jì)能有效減少金屬疲勞的產(chǎn)生,但在實(shí)際的臨床工作中,器械分離和(或)變形還是時(shí)有發(fā)生,特別是在彎曲的細(xì)小根管中。Calberson FL[18]的研究指出,器械變形大多發(fā)生在F3,其中很大一部分原因是因?yàn)镻roTape修形銼的錐度變化是拋物線形,其尖端直徑增大的速率比其他銼要大,因此,對(duì)于根尖預(yù)備來(lái)說(shuō),與其他的銼相比,修形銼的錐度就太大了,此時(shí)樹(shù)脂的抵抗力與銼本身的剛性就導(dǎo)致了器械的形變,甚至折斷。當(dāng)然,臨床中的器械折斷還有其他的原因,如用力過(guò)大、器械的使用方法、根管的解剖形態(tài)等,因此在實(shí)際工作中,為了降低銼分離的發(fā)生率,要特別小心,注意使用次數(shù),正確掌握銼的使用方法,注意銼的使用注意事項(xiàng)等等[19-22]。
3結(jié)論
綜上所述,ProTaper[23-24]銼在彎曲根管中,與不銹鋼K銼相比,能快速有效的完成根管的預(yù)備,得到理想的根管形態(tài),但在重度彎曲的根管中,如\"S\"形根管,由于修形銼的大錐度設(shè)計(jì),可造成根管的拉直、根管偏移、根尖部臺(tái)階以及歧岥的產(chǎn)生等,因此很多學(xué)者都建議,可以把ProTaper銼與一些小錐度、彈性大的鎳鈦銼聯(lián)合使用,如標(biāo)準(zhǔn)鎳鈦K銼、Hero642[25-27]等,即用成形銼預(yù)備根管的冠2/3,利用其大錐度設(shè)計(jì)完成根管口的敞開(kāi),再用他的小錐度彈性大的銼預(yù)備根尖1/3,從而得到理想的根管形態(tài),從而有利于根管的沖洗和充填,提高了根管治療的成功率。
另外,在操作過(guò)程中,還要注意器械的變形及折斷,應(yīng)采取各種方法盡量避免這種情況的發(fā)生。
參考文獻(xiàn):
[1]Bergmans L,Van Cleynenbreugel J,Beullens M,et al.Progressive versus constant tapered shaft design using NiTi rotary instruments[J].Int Endod J,2003,36(4):288-295.
[2]Schafer E,VlassisM.Comparative investigation of two rotary nickel-titanium instruments:ProTaper versus RaCe. Part Shaping ability in simulated curved canals[J].Int Endod J,2004,37(4):229-38.
[3]Sch?fer E,Erler M,Dammaschke T.Comparative study on the shaping ability and cleaning efficiency of rotary Mtwo instruments.Part 1.Shaping ability in simulated curved canals[J].Int Endod J,2006,39(3):196-202.
[4]Yun H, Kim SK.A comparison of the shaping abilities of 4 nickel titanium rotaryinstruments in simulated root canals[J].Oral Surg Oral Med Oral Pathol Oral Radiol Endod,2003,95(2):228-33.
[5]Yosbimine Y,Ono M,Akamine A.The shaping effects of three nickel-titanium rotary instruments in simulated shaped canals[J].J Endod,2005,31(5):373-5.
[6]Cunningham CJ,Senia ES.A three 2 dimensional study of canal curvatures in the mesial root of mandibular molars[J].J Endod,1992,18(6):294-300.
[7]Veltri M,Mollo A,Paolo Pini P,et al.In Vitro Comparison of Shaping Abilities of ProTaper and GT Rotary Files[J].J Endod,2004,30(3):163-166.
[8]Ersev H,Yilmaz B,Cift?io?lu E,et al.A comparison of the shaping effects of 5 nickel-titanium rotary instruments in simulated S-shaped canals[J].Oral Surg Oral Med Oral Pathol Oral Radiol Endod,2010,109(5):e86-93.
[9]Zhang L,Luo HX,Zhou XD,et al.The shaping effect of the combination of two rotary nickel-titanium instruments in stimulated s-shaping canals[J].J Endod.2008,34(4):456-458.
[10]Ding-ming H,Hong-xia L,Cheung GS,et al.Study of the Progressive Changes in Canal Shape After Using Different Instruments by Hand in Simulated S-Shaped Canals[J].J Endod, 2007,33(8):986-9.
[11]Jodway B,Hülsmann M.Int Endod J.A comparative study of root canal preparation with NiTi-TEE and K3 rotary Ni-Ti instruments[J].Int Endod J,2006,39(1):71-80.
[12]Sonntag D,Ott M,Kook K,et al.Root canal preparation with the NiTi systems K3, Mtwo and ProTaper[J].Aust Endod J,2007,33(2):73-81.
[13]Calberson FL,Deroose CA,Hommez GM,et al.Shaping ability of ProTaper nickel-titanium files in simulated resin root canals[J].Int Endod J,2004,37(9):613-623.
[14]Hayashi Y,Yoneyama T,Yahata Y,et al.Phase transformation behaviour and bending properties of hybrid nickel-titanium rotary endodontic instruments[J].Int Endod J,2007,40(4):247-253.
[15]Testarelli L,Plotino G,Al-Sudani D,et al.Bending Properties of a New Nickel-Titanium Alloy with a Lower Percent by Weight of Nickel[J].J Endod,2011,37(9):1293-1295.
[16]Sattapan B,Nervo GJ,Palamara JE,et al.Defects in rotary nickel-titanium files after clinical use[J].J Endod,2000,26(3):161-165.
[17]Berutti E,Chiandussi G,Gaviglion I,et al.Comparative analysis of torsional and bending stresses in two mathematical models of nickel-titanium rotary instruments: ProTaper versus ProFile[J].J Endod,2003,29(1):15-19.
[18]Calberson FL,Deroose CA,Hommez GM,et al,Shaping ability of ProTaper nickel-titanium files in simulated resin root canals[J].Int Endod J,2004,37(9):613-623.
[19]Kakar S,Dhingra A,Sharma H.Shaping potential of manual NiTi K-File and rotary ProTaper and analyzing the final outcome of shaped canals using CT[J]. J Contemp Dent Pract,2013,14(3):451-455.
[20]Faria G,Kuga MC,Ruy AC,et al.The efficacy of the self-adjusting file and ProTaper for removal of calcium hydroxide from root canals[J].J Appl Oral Sci,2013,21(4):346-350.
[21]Can ED,Gerek M,Kayahan MB,et al.Comparision of two different preparation protocol of Ni-Ti Rotary PathFile-ProTaper instruments in simulated s-shaped canals[J].Acta Odontol Scand,2014,72(1):76-80.
[22]Aguiar CM,Sobrinho PB,Teles F,et al.Comparison of the centring ability of the ProTaper? and ProTaper Universal? rotary systems for preparing curved root canals[J].Aust Endod J,2013,39(1):25-30.
[23]Cecchin D,de Sousa-Neto MD,Pécora JD,et al.Cutting efficiency of four different rotary nickel: Titanium instruments[J].J Conserv Dent,2011,14(2):117-119.
[24]Viana AC,Chaves Craveiro de,Melo M,et al.Relationship between flexibility and physical, chemical, and geometric characteristics of rotary nickel-titanium instruments[J].Oral Surg Oral Med Oral Pathol Oral Radiol Endod,2010,110(4):527-533.
[25]Zhang L,Luo HX,Zhou XD,et al.The shaping effect of the combination of two rotary nickel-titanium instruments in simulated S-shaped canals[J].J Endod,2008,34(4):456-458.
[26]Zare Jahromi M,Mirzakouchaki P,Mousavi E,et al.Fracture strength of mesiobuccal roots following canal preparation with hand and rotary instrumentation: an in vitro study[J].Iran Endod J,2011,6(3):125-128.
[27]Hu XL,Ling JQ,Chen H,et al.Clinical evaluation of two types of NiTi rotary instruments in preparation of root canals[J].Zhonghua Kou Qiang Yi Xue Za Zhi,2005,40(1):30-33.
編輯/肖慧