근단부크기에따른 customized master cone 의치근단밀폐효과에관한연구 홍혜영 최호영 최기운경희대학교치과대학치과보존학교실 ABSTRACT EFFECTIVENESS OF CUSTOMIZED MASTER CONE ON APICAL SEALING IN VARIOUS APICAL SIZE OF PREPARED ROOT CANALS Hye-Young Hong, Ho-Young Choi, Gi-Woon Choi Department of Conservative Dentistry, College of Dentistry, KyungHee University The purpose of this study is to evaluate the effectiveness of customized master cone on apical sealing in various apical size of prepared root canals, that is MAF(Master Apical File) and to know at which apical size the apical leakage is to be significantly reduced using customized master cone. 120 extracted single rooted premolars were divided into four groups according to their apical size(maf), #30, 40, 50 and 60. And then, each group was subdivided into three in accordance with three obturation methods, lateral condensation with standardized master cone, lateral condensation with chloroform-dipped customized master cone, and continuous wave of obturation technique. Resorcinol-formaldehyde resin was used for the microleakage test of this study. Teeth were sectioned horizontally at 1.5mm(Level 1), 2.5mm(Level 2), and 3.5mm(Level 3) from the anatomical root apex using low speed microtome. All sections were examined under 40 magnification with a stereomicroscope, photographed, and then scanned. With the scanned images, resin-infiltrated area presenting the microleakage was calculated using SigmaScan/Image, and the ratio of leakage to the total root canal area of each group was analyzed statistically(one way ANOVA). The results were as follows ; 1. In groups of MAF #30, there was no significant difference of mean leakage ratio among three obturation methods at all three levels. 2. In groups of MAF #40, the group using lateral condensation with customized master cone had the lowest mean leakage ratio at all three levels, but there was no significant difference among three obturation techniques. 3. In groups of MAF #50, the mean leakage ratio of the group using lateral condensation with standard master cone was the highest among those of three obturation techniques at level 1, and this difference was statistically significant(p<0.05). 4. In groups of MAF #60, the groups using lateral condensation with standard master cone had also the highest mean leakage ratio at all levels, but there was no significant difference at level 1 and 2. At level 3, the leakage of the group using lateral condensation with standard master cone was significantly higher than that of the group using continuous wave of obturation(p<0.05). The results of this study suggested that the obturation method using customized master cone or the continuous wave of obturation is more effective for apical sealing than that using standardized master cone when MAF is larger than #50. 66
근단부크기에따른 customized master cone 의치근단밀폐효과에관한연구 Ⅰ. 서론 근관치료과정은근관와동형성, 근관형성그리고근관충전의세단계로나눠지며, 성공적인근관치료를위해서는근관내감염된치수조직과세균및세균독성산물을제거하고근관충전을하여야한다. 근관충전의성공은대개근관형성과정에달려있다. Schilder 1) 는성공적으로형성된근관의형태는근단부로갈수록좁아지고치관부로향하면서넓어지는원뿔형태를가지면서치근단공이변위되지않고최소한으로유지된상태라고하였으며, 이러한형태가될때근관을성공적으로충전할수있는조건이된다고하였다. 근관충전은외부자극원으로부터근관의재감염을방지하기위하여근관을삼차원적으로폐쇄하여야하며, 근관충전이불완전할경우근관치료실패의주요원인이된다 2). 근관치료의실패는변성된치수잔사와함께근관내에세균과독성산물과같은원인요소가잔존하여근관계를계속적으로오염시키는것이주된원인이된다. 근관의세척과형성의중요성과더불어근관충전또한근관세척과형성과정중에완전히제거되지못한자극물들을근관내에밀폐시키고, 누출이일어남으로써근관내세균번식의근원을제공하는것을차단하는목적을가지는중요과정이라할수있다. 특히, Wein 3) 은치근단부위에서적절한밀폐가이루어지지못하는것이근관치료실패의가장흔한원인이된다고하였다. 근관충전법은측방가압과수직가압으로나눌수있다. 측방가압법은치근단부위의근관형성에사용하였던기구의번호와동일하게규격화된 gutta-percha를 master cone 으로선택하여근단공부위를충전한다. 이와같이표준화된 master cone을변형시키지않고충전하기위해서는형성된근단부의형태가선택한 master cone의끝부위의형태와유사하게둥글고매끈하여야한다. 그러나실제임상에서근단부가흡수되었거나근단부발육이불완전한경우, 또는과잉기구조작이나천공등으로근단공이넓고불규칙한형태를가지는경우에보통의표준화된 gutta-percha cone으로는치근단부위를효과적으로밀폐하기가어렵다. 이러한경우표준화된 gutta-percha cone을 chloroform 과같은용제에연화시킨후근단부의인상을채득하여 customized master cone을제작하여충전하는방법을사용할수있다. 1914년 Callahan 4) 에의해소개된이방법은 chloroform에연화시킨충전물의수축 5) 또는용제의독성 6,7) 등문제점이제기되어왔으나, customized master cone의제작시사용되는 chloroform의양이나적용방법등을개선할경우치근단밀폐효과가우수하다 8). 또다른근관충전방법으로는 gutta-percha를열로연화시켜충전하는방법이있다. 열을가하는방법에는전열기가달린 plugger로수직가압하는방법, 열로연화시킨 gutta-percha를 주입하는방법, 운반체표면에 gutta-percha 를입혀근관내에적용하기전에가열하는 core-carrier technique, 또는회전기구로열가압하여충전하는방법등이있다 9). 이중최근에소개된 continuous wave 충전법은 System B를이용하여 gutta-percha를연화시켜수직가압하는방법으로, 근관내에서 gutta-percha의연화와가압을동시에시행함으로써삼차원적인충전을빠르고정확히얻을수있는근관충전방법이다 10). Chloroform 등의용제를이용하여 customized master cone을제작, 근관충전하였을때치근단부위의누출이감소된다는사실은이미여러연구들을통하여보고된바있다 11). 특히, 단면이둥글고매끈한근관에서는그효과에한계가있으나표준화된 master cone의형태에서벗어난해부학적형태를가지는리본형이나납작한근관에서는 customized master cone으로치근단밀폐효과를증가시킬수있다 12). 또한 Wein은 3) 근관이 50번이상으로확대될경우근관단면의형태에있어서편심성 (eccentricity) 이나불규칙성이증가하기때문에이러한근관에서는보통의표준화된 master cone의사용으로근단부의밀폐를이루기가어렵다고하였다. 그러나 MAF(Mater Apical File) 가어느정도일때 customized master cone을사용할경우효과적인근관충전을할수있는지에관한연구가적다. 따라서본연구에서는발거된실험치아에다양한 MAF를설정한뒤표준화된 master cone과 customized master cone으로충전한후그충전효과를비교하고어느정도크기의 MAF에서 customized master cone이근단부밀폐에효과를나타내는지를판단하며, 근관폐쇄효과를열연화가압충전법인 continuous wave 충전법과비교하고자한다. 1. 실험재료 Ⅱ. 실험재료및방법 1) 실험치아발거된단근관소구치 120 개를실험치아로사용하였다. 치근표면에부착된치석과잔사들은 scaling 과 root planning 을시행하여제거하였고, 5.25% 차아염소산나트륨 (NaOCl) 용액에 48 시간담가두어치근에부착된조직을제거한후증류수에보관하였다. 근관내접근이용이하도록치아의백악법랑경계부위에서치관을절단, 제거하였다. 2) 근관형성기구근관형성은수동 stainless steel file 인 K-flexofile (Maillefer, Swiss) 를사용하였으며, 근관의치경부확대는 67
Gates-Glidden drill (Maillefer, Swiss) 을사용하였다. 3) 근관충전재료및기구근관충전재료는 standard gutta-percha cone (Diadent, Korea) 과 accessory gutta-percha cone(diadent, Korea), 그리고실러로는 AH-26 (Dentsply De Trey, Germany) 을사용하였고, customized master cone 제작시 cone의연화를위하여 chloroform(duksan Pure Chemicals Co., Korea) 을사용하였다. 측방가압법시근관충전기구로 finger spreader(pierce Co., Japan) 를사용하였으며, continuous wave 충전법시에는 System B(Analytic Technology,U.S.A.) 와 Buchanan plugger (Analytic Technology, U.S.A.), 그리고근관의 backfilling은 ObturaⅡ(Texceed, U.S.A.) 를사용하였다. 4) 미세누출실험재료및기구미세누출실험을위해침투시킬레진용액은 resorcinol (Sigma Chemical Co., Switzerland), formaldehyde (Showa Chemical Co., Japan), KOH(Showa Chemical Co., Japan) 를사용하여제작하였다. 레진침투가완료된치아는 epoxy resin(kumho P&B Chemicals Inc., Korea) 에매몰하여블럭을형성하였으며, 치아블럭의절단을위해 low speed microtome(isomet Buehler, U.S.A.) 을사용하였다. 2. 실험방법 1) 실험군의분류 120 개의실험치아를 MAF(Master Apical File) 의크기에따라 30, 40, 50, 60 번으로형성한 4 개군으로나누고, 각군을충전방법에따라 3 개군으로다시세분하였다. 즉, 표준화된 master cone 으로측방가압충전한군, customized master cone 으로측방가압충전한군, continuous wave 충전법으로충전한군으로분류하였다. 각군의분류는 Table 1 과같다. 2) 근관형성치관을절단한실험치아는근관내에 10 번 K-flexofile 을삽입하여치근단공을확인한후치근단공에서 0.5mm 를뺀길이를근관작업장으로결정하였다. 실험군에따라 MAF(Master Apical File) 를각각 30, 40, 50, 60 번으로형성한후통법의 step-back 방법으로근관을형성하였으며, 근관의치경부는 3, 4 번 Gates-Glidden drill 로확대, 형성하였다. 근관세척은 5.25% 차아염소산나트륨용액을사용하였으며, step-back 방법의매단계마다 10 번 K- flexofile 로치근단공을확인하였다. 3) 근관충전 (1) 표준화된 master cone 을사용한측방가압법근관형성이완료된후 paper point 로근관을건조시키고, 형성된 MAF( 즉, 30, 40, 50, 60 번 ) 에해당하는표준화된 Table 1. Classification of Experimental Groups MAF N Obturation Method 10 (A) Lateral condensation with standard master cone #30 10 (B) Lateral condensation with customized master cone 10 (C) Continuous wave of obturation 10 (A) Lateral condensation with standard master cone #40 10 (B) Lateral condensation with customized master cone 10 (C) Continuous wave of obturation 10 (A) Lateral condensation with standard master cone #50 10 (B) Lateral condensation with customized master cone 10 (C) Continuous wave of obturation 10 (A) Lateral condensation with standard master cone #60 10 (B) Lateral condensation with customized master cone 10 (C) Continuous wave of obturation *MAF ; Master Apical File 68
근단부크기에따른 customized master cone 의치근단밀폐효과에관한연구 gutta-percha master cone 을선택, 작업장길이까지시적하여 tugback 을확인한후 master cone 에 AH-26 을도포하여근관에삽입하였다. 이후 2, 3, 4 번 finger spreader 와 accessory cone 을사용하여통법의측방가압법을시행한뒤근관와동입구에서 3mm 하방까지잉여충전물을제거하였다. (2) Customized master cone 을사용한측방가압법작업장보다 2 3mm 짧게들어가는표준화된 guttapercha master cone 을선택하여 cone 의끝부분 2 3mm 를 chloroform 에 1 2 초간연화시킨후, 작업장길이만큼근관내에삽입하여치근단부의인상을채득하였다. 이렇게제작된 customized master cone 은 chloroform 의기화를위해 5 분간공기건조시킨후 paper point 로건조시킨근관내에 AH-26 을도포하여삽입하였다. 이후전과동일한방법으로측방가압법을시행하였다. (3) Continuous wave 충전법근관의작업장길이보다 4mm 짧게들어가는 Buchanan plugger 를선택하여 AH-26 을도포한비표준화된 guttapercha cone 을근관내에위치시켰다. System B 의온도를 200, 출력을 10 에맞춘뒤가열된 Buchanan plugger 로 binding point 보다 4mm 짧은곳까지삽입, touch switch 를놓은상태에서 binding point 까지수직가압한후 20 초간그위치에서유지시켰다. 그후 switch 를누른상태에서 plugger 와 gutta-percha 를제거한뒤, 나머지부위는연화온도를 160 로설정한 Obtura Ⅱ 로충전하였다. 4) 미세누출실험실험치아들은근관와동입구를 IRM(The L.D., Caulk, Dentsply, U.S.A.) 으로충전하고, sealer 의경화를위해 100% 습도하실온에서 2 일간보관하였다. 이후치근단 2mm 를제외한나머지부위를 nail polish 로 2 회도포하였다. 미세누출실험을위해 resorcinol-formaldehyde resin 을제작하여실험치아에침투되도록하였다. Resorcinolformaldehyde resin 은 formaldehyde 용액을 KOH 를이용하여 ph 8.2 로맞춘뒤 2ml 당 1.3g 의 resorcinol 과혼합하여제작하였다. 준비된 resorcinol-formaldehyde resin 용액에실험치아를담가레진이침투되도록 4 에서 5 일간보관하였으며이후치아를용액에꺼내어상온에서 4 일간방치함으로써레진의경화를유도하였다. 5) 치아의절단및절단면관찰레진의침투가완료된실험치아들은치근면에도포된 nail polish 를제거하고 epoxy resin 에포매한뒤, low speed microtome 을이용하여해부학적근첨에서 1.5mm(Level 1), 2.5mm(Level 2), 3.5mm(Level 3) 떨어진위치에서수평절단하였다. 수평절단한시편의절단면은 stereomicroscope (Olympus, Japan) 으로 40 배확대관찰한뒤사진촬영하여이를 computer scanner 로 scanning 하였다. Scanning 한 image 에서전체근관면적에대한레진침투면적을 Sigmascan Pro 5/Image software TM (Jandel, Scientific software, San Rafael, CA, U.S.A.) 를이용하여측정한후누출도를평가하였다. 6) 누출률의측정및평가누출률 (%) 은전체근관면적에대한레진침투면적을백분율로계산하였으며, 이를 WINKS 4.1c Professional Edition(TexaSoft TM, U.S.A) 분석프로그램을이용하여일원변량분석법 (One-way ANOVA) 과 Newman-Keuls multiple comparisons test 로각군간의유의성을검정하였다. Ⅲ. 실험성적 MAF(Master Apical File) 가 30 번인군에서는 Level 1, Level 2, Level 3 으로진행할수록평균누출률이감소하였으나, 각 Level 에서 3 가지충전방법간에평균누출률에는큰차이가없었으며 (Table 2, Fig. 1) 통계분석결과유의성이없었다. MAF 40 번인군에서는 customized master cone 으로측방가압충전한군이모든 Level 에서평균누출률이가장낮았으며 Level 2 를제외하고는표준화된 master cone 으로측방가압충전한군에서평균누출률이가장높았고, Level 2 에서는 continuous wave 충전법으로충전한군의누출이가장높았으나 (Table 2, Fig. 2), 각군간에통계학적유의성은없었다 (p>0.05). MAF 50 번인군에서는 Level 1 에서표준화된 master cone 으로측방가압충전한군의평균누출률이가장높았으며이는나머지두충전방법과유의한차이를보였다 (p<0.05). 모든 Level 에서 customized master cone 으로측방가압충전한군의평균누출률이가장낮았으며, Level 2 에서는표준화된 master cone 으로측방가압충전한군이, Level 3 에서는 continuous wave 충전법을사용한군의평균누출률이가장높았으나 Level 2, 3 에서는통계학적유의성이없었다 (Table 2, Fig. 3). MAF 60 번인군에서는모든 Level 에서표준화된 master cone 으로측방가압충전한군의평균누출률이가장높았으며, Level 1 에서는 customized master cone 으로측 69
Table 2. Mean leakage ratio (%) at 3 Levels MAF Level 1 Level 2 Level 3 (Average±standard deviation) A 8.22±5.35 2.98±2.38 1.55±1.05 #30 B 6.89±9.75 3.54±5.77 1.56±1.10 C 8.20±8.52 3.94±2.31 2.52±1.19 A 12.53±10.62 5.02±4.87 2.40±3.13 #40 B 7.11±10.34 1.99±2.02 0.42±0.42 C 8.39±3.90 5.14±3.29 1.89±1.47 A 25.17±22.73 2.84±3.51 1.02±0.75 #50 B 3.57±3.32 1.99±2.34 0.73±0.84 C 6.14±7.30 2.64±1.95 2.11±2.13 A 13.58±13.31 4.19±3.45 1.81±1.22 #60 B 4.77±3.45 3.88±3.94 1.07±0.83 C 6.04±6.88 2.44±3.46 0.74±0.67 A : Lateral condensation with standard master cone B : Lateral condensation with customized master cone C : Continuous wave of obturation Level 1 : 1.5mm from the apex, Level 2 : 2.5mm from the apex, Level 3 : 3.5mm from the apex Fig. 1. Mean leakage ratio(%) at 3 Levels (MAF #30) A : Lateral condensation with standard master cone B : Lateral condensation with customized master cone C : Continuous wave of obturation Fig. 2. Mean leakage ratio(%) at 3 Levels (MAF #40) A : Lateral condensation with standard master cone B : Lateral condensation with customized master cone C : Continuous wave of obturation 방가압충전한군이, Level 2, 3 에서는 continuous wave 충전법으로충전한군의평균누출률이가장낮았다 (Table 2, Fig. 4). 유의성검정결과 Level 1, 2 에서는통계학적유의성이없었으나, Level 3 에서평균누출률이가장낮은 것으로나타난 continuous wave 충전법을사용한군과표준화된 master cone 으로측방가압충전한군사이에는유의한차이를보였다 (p<0.05). 70
근단부크기에따른 customized master cone 의치근단밀폐효과에관한연구 Fig. 3. Mean leakage ratio(%) at 3 Levels (MAF #50) A : Lateral condensation with standard master cone B : Lateral condensation with customized master cone C : Continuous wave of obturation Fig. 4. Mean leakage ratio(%) at 3 Levels (MAF #60) A : Lateral condensation with standard master cone B : Lateral condensation with customized master cone C : Continuous wave of obturation Table 3. Statistical analysis of mean leakage ratio(%) in experimental groups MAF(Master Apical File) #30 #40 #50 #60 F value 0.09 1.02 7.19 2.88 Level 1 P value 0.9164 0.3724 0.0031* 0.0733 Level 2 Level 3 F value 0.16 2.48 0.28 0.66 P value 0.8565 0.1026 0.7614 0.5253 F value 2.53 2.6 2.73 3.45 P value 0.0986 0.0928 0.0835 0.0462* * statistically significant at P<0.05 Table 4. Statistical analysis of mean leakage ratio(%) between groups : Newman-Keuls multiple comparisons test MAF #50, Level 1 MAF #60, Level 3 A(Standard) B(Customized) C(Continuous) A(Standard) B(Customized) C(Continuous) A * * ND * B * ND ND ND C * ND * ND * statistically significant at P<0.05 ND ; no statistical difference Ⅳ. 총괄및고안 근단부의인상을채득하여 customized master cone 을제작한뒤충전을시행하는방법은근관형성된근단부의형태가규격화된 gutta-percha 와같이둥글지않은경우에 근단부에서근관벽과 gutta-percha 와의적합성을좋게함으로써실러로충전될면적을감소시키게되는데, 이는후에실러의용해로인해발생될치근단밀폐의손상을감소시키게된다 13). 이러한 customized master cone 을제작하는방법은크게용제를이용하는방법과열을이용하는방 71
법으로나눌수있다. Gutta-percha의연화에사용될수있는용제로는 chloroform, eucalyptol, halothane, xylene, orange terpenes 등이있으며이중 chloroform이가장흔히사용되는용제이다. Chloroform으로 gutta-percha를연화시켜 customized master cone을제작시에는충전물의수축이문제가되었으나 14) 이는 chloroform의적용방법에대한고려가선행되어야한다. Chloroform의사용시에발생되는충전물의수축은사용하는 chloroform의양과밀접한관련이있다. Keane과 Harrington 15) 은 chloroform의사용량에따른근단부폐쇄효과를연구하였는데, master cone의근단부 4 5mm를 chloroform에 1초간 3회, 2회, 1회각각 dipping하고근단부인상을채득한뒤충전하였을때 chloroform을많이사용할수록치근단누출의정도가증가하는결과를얻을수있었다. 즉, chloroform을사용한이전의연구들에서많은수축과누출을보였던것은 chloroform의사용량이많았기때문이며, customized master cone의제작을위해근관을형상화하는데는 1초간 dipping하는것으로충분하다고하였다. 본실험에서는 customized master cone을제작하기위해 cone의근단부 2 3mm를 chloroform에 1 2초간연화시켰으며충전을시작하기전에 chloroform의기화를위해 5분간공기건조시킴으로써 chloroform으로인한충전물의수축을최소화하고자하였다. Chloroform을사용하여 customized master cone을제작시수축을최소화하기위한또다른고려사항은근관충전을시작하기전에제작된 master cone으로부터 chloroform이충분히기화할시간을주었는지를들수있다. 앞에서언급한 Keane과 Harrington의연구 15) 에서 3회 dipping한군에서는충전을시행하기직전에 3번째 dipping을한뒤근관에적용시키고바로근관충전과정을진행함으로써 chloroform이근관밖에서충분히기화할시간을부여하지못한것을누출증가의원인이라고하였다. Metzger 16) 는 master cone을 chloroform에연화시켰을때 cone의 plasticity가상실되는시간을 chloroform이기화되는속도와혼동할수있음을지적하였는데, 실제로 cone의 plasticity 는건조후 15초이내에대부분이상실되나, chloroform의기화는 3분후 62% 가진행된다고하였다. 따라서 chloroform에 dipping한뒤 gutta-percha cone에충분한구강외건조시간을부여하는것이필요하다. 치근단부위의근관형성의크기를어느정도로할것인가를결정하는데있어서 Wein 3) 은근관형성하기전초기근관에적합되었던크기의파일 (IAF; Initial Apical File) 에서 3단계큰파일의크기만큼형성하는것을추천하였는데이때의파일을 MAF(Master Apical File) 라고하였다. 이것은근단부형성이완전히이루어졌거나직선적인근관 에서는대부분적용될수있으나치근단부위에흡수가있거나의원성으로근단공이이미넓어져있는만곡근관에서는적용하기어려운경우가많다. 근단공부위가적절히세척, 밀폐되기위해서는최소 20 번이나 25 번이상으로기구조작하는것이필요하지만근단공이넓어질수록근단공의찢어짐 (tearing) 이나근단공부위에서근관충전물주위로의누출발생가능성이커지게된다 17). 따라서근단부의근관형성시에는근단공을넓히는것이목적이아니라깨끗이하는것이목적임을잊지말아야한다. 특히만곡된근관에서큰파일을근단부형성시사용하게되면치근단부위의 zip 이나 elbow, 또는근단부천공과같이충전을어렵게만드는상황을유발하게된다 18). 모든근관의 90% 정도에서만곡이관찰됨을볼때 19) 근단부형성의크기, 즉 MAF 의크기가커지면보통의표준화된 master cone 으로는치근단부위의완전한밀폐를기대하기어려운경우가많아진다고볼수있다. 본실험에서실험치아의해부학적근첨에서 1.5mm 떨어진부위인 Level 1 에서의평균누출률을보면표준화된 master cone 으로측방가압충전한경우, MAF 의크기가증가할수록누출률이증가하였음을확인할수있었다. 이에비교하여 customized master cone 으로측방가압충전한군과 continuous wave 충전법을사용한군의경우는 MAF 의크기에관계없이대체로비슷한평균누출률을나타내었다. 따라서 MAF 의크기가증가할수록표준화된 master cone 으로측방가압충전한군과나머지두충전법간의평균누출률의차이는점점증가되었으며, MAF 가 50 번인경우에는통계학적으로유의한차이를나타내었다. 그러나오히려 60 번인경우에는 Level 1 에서유의성있는누출률의차이를보이지않았는데, 이는 MAF 를 60 번으로형성한실험치아의경우근관이비교적크고직선적인경우가많았기때문인것으로생각되었다. 1967 년 Schilder 에의해소개된수직가압법 20) 은기구를열에달구어사용하였던고전적인방법으로는시간소모와기술적어려움이존재하여이후에 Endotec(Caulk, Milford, DE) 이나 Touch n Heat(Analytic Technology, U.S.A.) 과같은전기를이용한장치들이개발되었으나 21) System B(Analytic Technology, U.S.A.) 가소개되면서 continuous wave 충전법이가능하게되어빠르고삼차원적인수직가압충전을할수있게되었다. Continuous wave 충전법은작업장보다 4mm 짧게들어가는 Buchanan plugger 를미리선택하여이에맞는비표준화된 gutta-percha cone 을선택, 사실상 1 개의 cone 이근단부의충전을담당하게된다. 따라서근단협착부로부터매끈하고일정한경사도를갖는형태로근관이형성된후에이에잘적합되는 cone 을선택하는것이중요한데 22), 신, 최등 23) 의연구에의하면협설측으로넓은근관에서는 contin- 72
근단부크기에따른 customized master cone 의치근단밀폐효과에관한연구 uous wave 충전법을사용했을때 sealer 로채워진공간이컸음을밝힌바있다. 본연구에서도 continuous wave 충전법을사용한군에서 gutta-percha 는근관내에서둥글고균질한형태로충전되었으나근관벽의불규칙한부위는대부분 sealer 로채워져있었음을알수있었다. 현재다양한경사도를가지는 (.04,.06,.08,.10,.12 taper) rotary Ni-Ti file 을근관형성에사용했을경우에는형성된근관의경사도에맞게규격화된 gutta-percha master cone 을선택함으로써쉽고정확히 continuous wave 충전법을시행할수있을것으로생각된다. 본연구의결과, 근단부형성의크기가커질수록기존의규격화된 master cone 의 tug-back 을이용한측방가압법으로는효과적인치근단밀폐를얻기가어려웠으며, 이는근단부형성에사용된기구의크기가커질수록규격화된 gutta-percha cone 의형태와같이매끈하고둥근형태로근단부형성을할수없게됨을미루어생각해볼수있다. 따라서근단부형성이 50 번파일크기이상이될경우에는근단부형태를복제한 customized master cone 을제작, 충전하거나 continuous wave 충전법과같은열연화가압충전법을사용하는것이치근단밀폐효과를증가시킬수있을것으로생각된다. Ⅴ. 결론 본연구는근단부크기에따른근관충전법간의치근단폐쇄효과를비교하기위해 120 개소구치를 MAF(Master Apical File) 의크기에따라 30, 40, 50, 60 번으로형성한군으로나누고, 각군을다시표준화된 master cone 을이용하여측방가압충전한군, customized master cone 으로측방가압충전한군, continuous wave 충전법으로충전한군으로세분하여근관충전한다음 resorcinol-formaldehyde resin 을이용한미세누출실험방법으로해부학적근첨에서 1.5mm(Level 1), 2.5mm(Level 2), 3.5mm (Level 3) 떨어진치근단부위의평균누출률을측정하여다음과같은결과를얻었다. 1. MAF 가 30 번인군에서평균누출률은 Level 1, 2, 3 에서세가지충전방법간에큰차이가없었다. 2. MAF 가 40 번인군에서평균누출률은 Level 1, 2, 3 에서 customized master cone 으로측방가압충전한군이가장낮았으며, Level 1, 3 에서는표준화된 master cone 으로측방가압충전한군이, Level 2 에서는 continuous wave 충전법으로충전한군의평균누출률이가장높았으나통계학적유의성은없었다. 3. MAF 가 50 번인군에서평균누출률은 Level 1 에서 customized master cone 으로측방가압충전한군과 continuous wave 충전법으로충전한군이표준화된 master cone 으로측방가압충전한군보다낮았으며, 통계학적으로유의한차이를보였다 (p<0.05). Level 2 와 3 에서는각군간에유의한차이가없었다. 4. MAF 가 60 번인군에서평균누출률은 Level 1, 2 에서 customized master cone 으로측방가압충전한군과 continuous wave 충전법으로충전한군이표준화된 master cone 으로측방가압충전한군보다낮았으나통계학적유의성이없었으며, Level 3 에서는 continuous wave 충전법과표준화된 master cone 으로측방가압충전한군사이에통계학적으로유의한차이를보였다 (p<0.05). 본연구결과 MAF 가 50 번이상인근관에서는표준화된 master cone 보다는 customized master cone 을제작하여근관충전하거나 continuous wave 충전법으로충전하는경우치근단누출을감소시킬수있을것으로판단된다. 참고문헌 1. Schilder H: Cleaning and shaping the root canal. Dent Clin North Am, 18:269, 1974. 2. Dow PR, Ingle JI: Isotope determination of root canal failure. Oral Surg Oral Med Oral Pathol, 8:1100-1104, 1955. 3. Wein FS: Endodontic Therapy. 5th ed., Mosby, 14, 317, 435-436, 1996. 4. Callahan JR: Rosin solution for the sealing of the dentinal tubuli and as an adjuvant in filling the root canals. J Allied Dent Soc, 9:53, 1914. 5. Wong M, Peters DD, Lorton L, Bernier EN: Comparison of gutta-percha filling techniques: three chloroform gutta-percha filling techniques Part 2. J Endodon, 8:4-9, 1982. 6. Morse DR, Martell B, Pike GC, Fantasia J, Esposito JV, Furst LM: A Comparative Tissue Toxicity Evaluation of Gutta-Percha Root Canal Sealers. Part Ⅰ. Six-hour Findings. J Endodon, 10:246-9, 1984. 7. Barbosa SV, Burkard DH, Spa ngberg LSW: Cytotoxic Effects of Gutta-percha Solvents. J Endodon, 20:6-8, 1994. 8. Beatty RG, Zakariasen KL: Apical leakage associated with three obturation techniques in large and small root canals. Int Endodon J, 17:67-72, 1984. 9. Gutmann JL, Witherspoon DE: Obturation of the Cleaned and Shaped Root Canal System. In Cohen S, Burns RC, editor: Pathways of the pulp, 7th ed., Mosby, 258-259, 327, 1998. 10. Buchanan LS: The continuous wave of obturation technique: Centered condensation of warm gutta-percha in 12 seconds. Dentistry Today, Jan, 1996. 11. Narracott P: An in vitro comparison of the single cone and lateral condensation techniques using friction-fitted and solvent dip-fitted primary gutta-percha cones. Aust Dent J, 34:49-51, 1989. 12. Metzger Z, Nissan R, Tagger M, Tamse A: Apical Seal by Customized versus Standardized Master Cones: A Comparative Study in Flat and Round Canals. J Endodon, 14:381-384, 1988. 13. Christie WH, Peikoff MD: Direct impression technique; 73
Sealing prepared apical foramen. J Canad Dent Assn, 3:174-181, 1980. 14. Zakariasen KL, Stadem PS: Microleakage associated with modified eucapercha and chloropercha root-canalfilling techniques. Int Endodon J, 15:67-70, 1982. 15. Keane KM, Harrington GW: The Use of Chloroformsoftened Gutta-percha Master Cone and Its Effect on the Apical Seal. J Endodon, 10:57-63, 1984. 16. Metzger Z, Assif O, Tamse A: Residual Chloroform and Plasticity in Customized Gutta-percha Master Cones. J Endodon, 14:546-549, 1998. 17. West JD, Roane JB: Cleaning and Shaping the Root Canal System. In Cohen S, Burns RC, editor: Pathways of the pulp, 7th ed., Mosby, 232, 1998. 18. Luiten DJ, Morgan LA, Baumgartner JC, Marshall JG: A Comparison of Four Instrumentation Techniques on Apical Canal Transportation. J Endodon, 21:26-32, 1995. 19. Christie WH, Peikoff MD: Conservative treatment of apical foramen; New root canal techniques. J Canad Dent Assn, 3:183-188, 1980. 20. 신정희, 최호영, 박상진, 최경규, 최기운 : 근단공이넓은치아의근관충전방법에따른치근단폐쇄효과에관한연구. 경희치대논문집, 21:1-16, 1999. 21. Ingle JI, West JD: Obturation of the radicular space. In Ingle JI, Bakland LK, editor: Endodontics 4th ed., A Lea & Febiger Book, 266, 1994. 22. Schilder H.:Filling root canals in three dimensions. Dent Clin North Am, 11:723-44, 1967. 23. Jerome CE: Warm Vertical Gutta-percha Obturation: A Technique Update. J Endodon, 20:97-99, 1994. 74
근단부크기에따른 customized master cone 의치근단밀폐효과에관한연구 사진부도설명 Fig. 5. Representative photograph of the group using lateral condensation with standard master cone at MAF #30, Level 1 ( 40). Fig. 6. Representative photograph of the group using lateral condensation with customized master cone at MAF #30, Level 1 ( 40). Fig. 7. Representative photograph of the group using continuous wave of obturation at MAF #30, Level 1 ( 40). Fig. 8. Representative photograph of the group using lateral condensation with standard master cone at MAF #40, Level 1 ( 40). Fig. 9. Representative photograph of the group using lateral condensation with customized master cone at MAF #40, Level 1 ( 40). Fig.10. Representative photograph of the group using continuous wave of obturation at MAF #40, Level 1 ( 40). Fig.11. Representative photograph of the group using lateral condensation with standard master cone at MAF #50, Level 1 ( 40). Fig.12. Representative photograph of the group using lateral condensation with master cone at MAF #50, Level 1 ( 40). Fig. 13. Representative photograph of the group using continuous wave of obturation at MAF #50, Level 1 ( 40). Fig.14. Representative photograph of the group using lateral condensation with standard master cone at MAF #60, Level 1 ( 40). Fig.15. Representative photograph of the group using lateral condensation with customized master cone at MAF #60, Level 1 ( 40). Fig.16. Representative photograph of the group using continuous wave of obturation at MAF #60, Level 1 ( 40). 75
사진부도 1 Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 9 Fig. 10 Fig. 11 Fig. 12 Fig. 13 Fig. 14 Fig. 15 Fig. 16 76