- 대한치과보철학회지 Vol 32 No 2, 1994 - 포스트코어의종류와접착방법이미세누출에미치는영향 서울대학교치과대학치과보철학교실 윤명재ㆍ이선형ㆍ양재호 Ⅰ 서론 치아우식이나외상등에의해서심하게파손된치아를수복하는방법으로사용되어온포스트코어는수복치과영역에서지속적인관심의대상이되어온중요한술식이다 (43) Pierre Fauchard는 18 세기에 wooden post를사용하였으며, G V Black은 gold foil로근관충전을한후 screw를사용하여치아를수복하였다 (21) 근관치료의시행빈도가크게늘어나고이러한치료의효과와예후가개선되어가면서근관치료를시행한치아를포스트코어를이용하여수복하는증례는크게증가하고있다 (25, 50) 포스트코어는최종수복물이구강내에서기능을할수있는충분한유지력을부여하며, 치근파절을방지하고 (17, 23, 치관부에이상이있을때재수복을가능하게한다 39, 43) 포스트코어의제작방법은여러문헌에서소개되고있으며 (3-5, 17, 39, 43), 제작된포스트코어로강화된치아는지 (17, 20, 22, 대치로사용하기에적절하다고보고된바있다 25, 39, 48) 그러나포스트코어에의한치아의수복은실패율이비교적높은것으로인식되어왔으며 (22), 이러한높은실패율로인해다양한수복방법의변화가유도되었다 (3-5, 39) 주조포스트코어와, 여러가지코어재료를이용한기성포스트가주로사용되고있으며, 일반적으로주조포스트코어가가장이상적인치관-치근축조법이라고인 정되고있고 (17) 임상적으로자주사용되고있지만, 몇가지장점으로인해기성포스트는그사용이계속증가되고있는경향을나타내고있다 (20, 21, 31, 35) 기성포스트와함께사용되고있는코어재료로는아말감, 콤포지트레진, 글래스아이오노머 (30) 가주로사용되고있으며, 이들재료중콤포지트레진은편리성으로인해물리적성질이아말감에비해열등함에도불구하고널리사용되고있다 (15, 48, 54) 콤포지트레진은중합시수축에의해레진 - 상아질접착을파괴하며, 구강내에서수분을흡수하여체적안정성이좋지않은단점을지니고있으나 (37), 시간절약과경제적인면에서우수하며 (31), 여러학자들에의해콤포지트레진이포스트코어축조에사용하기적합한물질이라는것이입증되었다 (27, 30, 54) 포스트코어의임상적인실패는포스트의유지력부족으로인한보철물의탈락, 포스트또는코어재료의파절, 치근의파절이주된원인으로지금까지의대부분의연구는포스트의유지력과치근내에서의응력분산에주안점을두고이루어져왔다 (25, 40) 일반적으로기성포스트코어가주조포스트코어에비해수복실패율이높다고보고되고있으며, 이는계면의수가증가함으로인해나타난다고보고된바있다 (22) 포스트가적절한유지력을얻기위해서는적절한시멘트의선택이필요한데, 인산아연시멘트는경화시의수축, 수용액에서의용해성, 낮은 ph, 그리고치아에직접접착되지않는단점이있지만, 그동안주된접착재료로사용되어왔다 (52, 53) 225

최근개발된 adhesive luting agent(ala) 는인산아연시멘트에비해유지력의증가, 물리적성질의개선, 미세누출의감소등의장점을지니고있으며, 치아에직접부착할수있는특징을나타낸다 수복물변연에서의미세누출은최근여러가지시멘트의개발과더불어그중요성이인식되고있으며, 미세누출, 혹은치아와수복물계면에서의세균적, 화학적, 분자적침투에대한변연투과도에의한치수손상과이차우식증으로인한수복물의실패도관심의대상이되고있다 (33) 이러한미세누출의방지를위하여, 치아에직접부착하는시멘트를사용하거나, 산부식접착법과상아 (12, 17, 38, 질접착재를이용하는방법등이제시되고있다 44) 본연구는임상적으로가장많이사용되는, 주조포스트와콤포지트레진코어재료를이용하는기성포스트에서치아에대한접착방법에따른변연에서의미세누출을측정하여비교함으로써그임상적인적용방안을제시하고자함에있다 Ⅱ 실험재료및방법 1 실험재료본연구에사용된재료는다음과같다 1) Verabond : Nonprecious alloy : Aalba Dent Inc USA 2) DuraLay : Acrylic resin : Reliance Dental Mfg Co USA 3) Scotchbond 2 : Dentin bonding agent : 3M Dental Product Division USA 4) Core-MAX : Composite resin core : Sankin Co Japan 5) Dentatus : Prefabricated post : Dentatus Co Switzerland 6) Panavia Ex : Composite resin cement : Kuraray Co Japan 7) Flecks : Zinc phosphate cement : Mizzy USA 2 시편제작포스트코어의종류및접착방법이수복물변연에서의미세누출에미치는영향을연구하기위하여치경부에치아우식이나수복물이없는발거된 40개의상하악전 치를본실험에사용하였다 각치아에대한치석제거및세척을시행하고, 고속에서 water spray-cooled diamond 를사용하여치아의장축과수직이되도록백아법랑경계 2mm 상방을절단하여해부학적치관을제거하였다 K- 파일을사용하여근관형성을한후통법에따라산화아연유지놀시멘트와 Gutta Percha cone 을사용하여측방충전법으로근관을폐쇄하였다 생리적식염수에 24 시간동안보관한후, 각군에 10 개의치아를임의로선택하여모두 4 개의군으로분류하여시편을제작하였다 각군에따른포스트코어의제작과접착방법은다음과같다 Ⅰ 군 : Peeso reamer(maillefer Ballaigues, Switzerland) 로근관을형성하고, DuraLay(Reliance Dental Mfg Co, Worth, I11) 자가중합형아크릴릭레진을사용하여근관의인상을채득한뒤, 절단된해부학적치관의치관부 3mm 까지코어를제작한후비귀금속합금 (Verabond : Aalba Dent Inc) 으로주조하여완성한주조포스트코어를인산아연시멘트를사용하여치아에접착시켰다 Ⅱ 군 : Ⅰ 군과같은방법으로제작된주조포스트코어의접착면을 sandblasting 하고, 접착될치아면을 Scotchbond 2(3M Dental Product Division, St Paul, Monn) 상아질접착재로처리한후 Panavia Ex(Kuraray Co, Tokyo, Japan) 접착성레진시멘트로치아에접착시켰다 Ⅲ 군 : Parallel-sided drill 을사용하여근관을형성하고기성포스트 (Dentatus) 를적합한후근단면을식각하고, Core-Max(Sankin Co, Japan) 콤포지트레진코어용콤포지트로코어를축조하였다 Ⅳ 군 : Parallel-sided drill 을사용하여근관을형성하고, 기성포스트를근관에접착한후근단면을식각하고 Scotchbond 2(3M Dental product Division, St Paul, Minn) 상아질접착재로처리한다음 Core- Max(Sankin Co, Japna) 레진코어용콤포지트를제조자의지시에따라사용하여코어를축조하였다 3 색소침투도측정위와같은방법으로각군에대해포스트코어를완성한후수복물의변연부위를제외한시편의나머지부분에 nail polisher를도포하고, 근단부위에서의누출을방지하기위해 sticky wax로근단부위를밀봉한후실 226

온의물 (27 ) 에 24 시간동안보관하였다 5 와 55 에서 100 회의 thermocycling(30 초잠금시간, 30 초이동시간 ) 을시행한후 2% basic fucsin dye 에 24 시간동안침지시킨다음, 시편을꺼내어물로세척한후치아표면을 pumice 로처리하여표면의염료를제거하였다 Low speed diamond stone(isomat, Buhler) 을사용하여, 치아장축과평행하게순설방향의단면으로절단한후 (Fig 1), 색소의침투도를거리측정현미경 (Fig 2)(Mitutoyou Co, Japan) 를사용하여 50 배의배율에서 mm 단위로염료가침투된길이를측정, 기록하였으며, 각군간에유의한차이를알아보기위해측정된결과를개인용컴퓨터 (IBM PC/386) 와 SPSS/PC+ software package 를사용하여통계적분석을시행하였다 Ⅲ 실험성적 각군에대한색소침투도는다음과같다 (Table 1, Fig 3) 시편의치아 - 수복물계면에서색소가침투된길이를측정하여미세누출정도를판별하였다 전체적인실험군간의통계적인유의차를비교하기위하여 oneway ANOVA 를시행한결과, 포스트코어의종류와접착방법에따라미세누출에유의한차이가인 Fig 1 Specimens of each group Table 1 The length of dye penetration of each group(mm) Fig 2 Measuring Microscope 227

Fig 3 Comparison of dye penetration in each group Table 2 Statistical analysis(duncan s multiple range test) 정되어 Duncan s multiple range test 를시행하였고, 각군간의통계적유의차를알아보기위해 t-test 를시행하였다 (Table 2) 각군간색소침투도에서는통계적으로유의한차이를나타내었다 (p<001) 인산아연시멘트로접착한주조포스트코어에서가장심한색소침투도를보였고, 레진시멘트로접착한주조포스트코어에서가장적은색소침투도를보였다 40 개의시편중주조포스트코어를제외한나머지의시편에서모두색소침투도를나타내었으며, 기성포스트와콤포지트레진코어를사용한두실험군 (Ⅲ 군, Ⅳ 군 ) 에서는상아질접착재를사용한경우 (Ⅳ 군 ) 에서더적은색소침투를나타내었지만두군간의통계적유의차는없었다 (p>005) Ⅳ 총괄및고안 포스트코어에의한회복물의임상적인성공여부는잔존상아질의양, 하중의양과방향, 포스트의설계, 형성 된근관에대한포스트의적합도, 시멘트층의질에의해결정된다 (40) 치관부파괴가심한무수치에대한전통적인치관-치근축조법은주조포스트코어였으나 (54), 임상적으로편리한기성포스트의출현으로인해, 포스트코어를제작하는여러가지방법들이소개되었다 (3-5, 35, 42, 43) Guzy등 (18) 은근관치료된치아의파절에관한연구에서포스트코어에의해강화된치아와강화되지않은치아들사이에서통계적으로유의할만한차이를나타내지않았다고하였으며, Lovdahl등 (28) 도같은결과를보고하였지만, 많은문헌에서는근관치료후포스트코어에의한강화는필요하다는것이강조되고있다 (34, 39, 46) Kantor등 (23) 은주조포스트코어와기성포스트에콤포지트레진코어를축조한경우를각각비교하여, 치관부손상이심한치아에서는주조포스트가더우수하다고하였으며, 콤포지트레진코어는단일치아수복에는적절하나, 중요한위치에놓여있는지대치에는사용해서안된다고결론을내렸다 Newberg등 (36) 은같은실험에서기성포스트와레진축조에의한방법도신뢰할만하다고하였으나, 콤포지트-치아계면에서의미세누출위험성을설명하였다 기성포스트와함께일반적으로사용되는코어재료인아말감과콤포지트레진의선팽창계수는 Phillips (41) 에의하면각각 25 cm/cm G와 30 cm/cm G로치아 (114 cm/cm G) 에비해 2-3배정도크게나타난다 직접법이나간접법에의해주조된포스트코어의경우, 주조체의정확성과시멘트의종류에따라변연에서의미세누출이영향을받을수있다 그러나기성포스트의경우에는코어재료자체가치아에적합되는경우이므로코어의물리적인성질이미세누출의큰변수로작용하게된다 아말감의경우선팽창계수가치아구조물에비해 2배정도크므로 (41, 50), 초기미세누출을방지하기위해코팔바니쉬의사용이강조되고있으나 (27), 부식이미세누출을방지한다는연구결과도있다 (27) 이연구에서사용된콤포지트레진의경우에는선팽창률의차이가아말감보다더크지만치아표면에대한처리방법에따라미세누출을감소시킬수있다고하였다 (7, 50) 코어재료로써아말감과콤포지트레진은적절하지만 (30) 선팽창률에따른수복물변연의누출은수복물실패의중요한원인으로작용한다 (8) 수복물변연에서의미세누출은코어형성재료의열팽 228

창률차이나중합시의수축등에의하여접착실패나간극형성에의해발생된다 (12, 13) 치관의대부분이상실되어포스트코어에의해수복되는경우에있어서이러한미세누출은여러가지계면을통해일어나기쉬우며, 이는잔존치질의이차우식을유발하여보철물수명의단축을초래한다 그동안많은학자들에의해주조금관이나도재전장관의변연에서의미세누출이연구되었으나 (30, 52, 53), 포스트코어에대한연구는자료가충분히않다 미세누출에영향을미치는인자로는보철물의정확성, 시멘트의용해성, 필름두께, 열팽창률의차이, 치아표면의처리등을들수가있다 (44, 51) Oritz등 (38), Mitchen등 (32), Hembree (19) 등은미세누출에대한저항을증가시키는방법으로법랑질을식각시키는방법을추천하고, Kanca와 Fusayama는각각상아질식각법을소개하면서미세누출을방지하려고하였으며 (16), 또한 Brannstrom등은상아질에직접부착되는이장재나시멘트는누출을방지하는효과가있다고주장하였다 (6) 일반적으로치아와수복물이긴밀하게적합되는경우미세누출과그에따른이차우식은감소한다 (9) 최근의연구에서는치아-상아질결합은중합수축에저항하고, 미세누출을감소시키기에충분할정도로강하다는것이밝혀지고있다 (52) 본연구결과에서도기성포스트에콤포지트레진코어로치관부를축조한경우, 상아질접착재로치아표면을처리한군에서작은양의미세누출을보이고있다 이는상아질접착재로처리한치아표면에서의미세기계적인결합이수복물의변연봉쇄효과를향상시킨다는주장과일치하고있다 (52) 또한치경부에서의법랑질의양은상대적으로적기때문에법랑질식각에의한치아와콤포지트레진의결합이중합수축이나, thermocycling 후에나타날수있는팽창의차이로인해파괴되어, 변연누출이나타나더라도상아질접착재를사용하므로써그정도가감소한다는것을보여준다 포스트코어에의한수복에있어서시멘트는포스트의유지와미세누출및회전성에대한저항의목적으로사용되고있다 (42) 대부분의포스트의실패는불충분한유지력에기인하므로, 시멘트는포스트의설계와함께포스트에의한수복의결정적인요소이다 (10) 인산아연시멘트, 인산폴리카복실레이트시멘트, 글 래스아이오노머시멘트, 그리고콤포지트레진시멘트를사용한 Para Post 의유지에관한연구에서유지력과시멘트종류사이에는상관관계가없다는것을나타내고있으나 (46), 다른연구들에서는상반된결과를보고하고있다 (36) 인산아연시멘트는 20 세기초반부터주조체의접착에일차적으로사용되어온시멘트이다 그러나경화시의수축, 수용액에서의용해성, 낮은 ph, 치아에직접적인결합의결여등이제한적인성질이되어왔다 본실험에서도인산아연시멘트로접착한대부분의주조체에서심한미세누출이있었음을관찰할수있었다 최근에개발되어사용되고있는치과용접착재는화학적, 미세기계적으로법랑질과상아질에접착된다 이러한 adhesive luting agent(ala) 들은인산아연시멘트에비해유지력의증가, 물리적성질의개선, 미세누출의감소와같은장점을지니고있다 (1, 2, 52) 접착성레진시멘트인파나비아는중합콤포지트레진에기초를둔재료로써, 치아와치과용합금, 도재에화학적, 기계적으로결합이가능하고, 구강내용액에대한용해성이낮고, 필름두께가작은특징을지닌다 (42) Anthony 등 (1) 은주조금관에서의접착성레진시멘트와인산아연시멘트의미세누출에대한연구결과파나비아가인산아연시멘트에비해적은미세누출을보인다고보고하였고, White 등 (52) 도 8 종의치과용접착재를사용하여실험을실시한결과인산아연시멘트가가장큰누출을보인반면, 파나비아는 thin film cement 를 tenure solution 과같이사용한경우다음으로적은누출량을나타내었다고보고하였으며, 인산아연시멘트나, 폴리카복실레이트시멘트, 글래스아이오노머시멘트와같이이온적반응을하는치과용접착재는경화시의수축과물에대한용해성때문에불리하다고주장하였다 McLean 등 (29) 은접착재의필름두께는미세누출의발생과관계가있는것같다는주장을하였으며, Davidson 등 (14) 은평평한표면에서얇은필름과같이한방향으로만수축이제한되는경우수축양상은감소하며이러한현상으로인해레진시멘트의얇은필름두께를설명하였다 (26) 그러나다른연구에서는레진시멘트로접착한주조금관에서의심한변연누출을보고하였고 (47), 그외에도레진시멘트의필름두께가다른시멘트보다더크다고보고한연구도있다 (51) 229

본실험에서는접착성레진시멘트인파나비아를상아질접착재와함께사용한주조포스트의경우에가장적은양의미세누출을보이고있는데이는 White 등 (52) 의실험과같은결과를보여주고있다 미세누출에는여러가지요인이영향을미치므로실험에서측정된색소침투도에절대적인의미를둘수는없겠으나, 각방법에따른누출정도의차이로상대적인비교를할수는있다고생각된다 Hoag 등 (20) 은 3 가지종류의포스트코어테크닉의비교연구에서포스트코어의제작법은주조금관장착만큼의중요성은없다고주장하였지만, 본연구에서는치아에최종회복물을장착하지않은상태에서의미세누출을측정하였는데, 이는최종회복물로인한변수를제거하여, 포스트코어자체의미세누출양상을비교하는데그의미를부여할수있다 본연구결과에서볼수있는것처럼, 적절한시멘트를이용한주조포스트의사용이가장바람직한임상적적용이될수있다는것을알수있고, 기성포스트도콤포지트레진코어재료사용시적당한치아표면처리에의해미세누출이감소된다는결과를볼때, 여러연구에서지지되고있는것처럼그임상적인효용성이인정될수있다고사료된다 Ⅴ 결론 저자는포스트코어의종류와접착방법에따른미세누출을연구하기위하여주조포스코어를인산아연시멘트로접착시킨경우, 주조포스트를상아질접착재로처리한근단면에파나비아로접착시킨경우, 기성포스트를수립한후콤포지트레진을이용하여치관부를축조한경우, 기성포스트를수립한후근단면에상아질접착재를도포하고콤포지트레진을축조한경우의 4 개군각 10 개의시편을제작하여색소침투에관한실험을행하고, 거리측정현미경을이용하여색소침투도를측정, 비교하여다음과같은결론을얻었다 1 각군간미세누출의정도에서는통계적으로유의한차이가인정되었다 (p<005) 2 인산아연시멘트로접착한주조포스트코어 (Ⅰ 군 ) 수복물에서가장심한미세누출양상 (15547± 00872mm) 을보였으며, 상아질접착재로처리한후접착성레진시멘트를접착한주조포스트코어 (Ⅱ 군 ) 수복 물에서가장적은미세누출 (01497±00872mm) 을나타내었다 3 상아질접착재를사용한 Ⅳ 군에서, 상아질접착재를사용하지않은 Ⅲ 군보다더작은양의미세누출을나타내었지만통계적으로유의하지는않았다 (p>005) 참고문헌 1 Anthony HL, Tjan D, Dunn JR, Grant BE Marginal leakage of cast gold crown luted with an adhesive resin cement J Prosthet Dent 1992 : 67 : 11 2 Anthony HL, Tjan D, Li T Seating and retention of complete crowns with a new adhesive resin cement J Prosthet Dent 1992 : 67 : 478 3 Baraban DJ A simplified method for making post and core J Prosthet Dent 1970 : 24 : 287 4 Baraban DJ Immediate restoration of pulpless teeth J Prosthet Dent 1972 : 28 : 607 5 Baraban DJ The restoration of pulpless teeth Dent Clin North Am 1967 : 12 : 6-33 6 Brannstrom M,Nyborg H Pulpal reaction to composite resin restorations J Prosthet Dent 1972 : 27 : 181 7 Bowen RL, Cobb EN A method for bonding to dentin and enamel J Am Dent Assoc 1983 : 107 : 734 8 Bullard RH, Leinfelder KF, Russel MC Effect of coefficient of thermal expansion on microleakage J Am Dent Assoc 1988 : 116 : 871 9 Chan KC, Fuller J, Khowassah M The adaptation of new amalgam and composite resin to pins J Prosthet Dent 1978 : 38 : 392 10 Chapman KW, Worley JL, von Fraunhofer JA Retention of prefabricated posts by cements and resins J Prosthet Dent 1985 : 54 : 649 11 Colley IT, Hampson EL, Lehman ML retention of post crown Br Dent J 1968 : 1-24 : 63 12 Crim GA Influence of bonding agents and composites on microleakage J Prosthet Dent 1989 : 61 : 571 230

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=Abstract= EFFECT OF TYPE AND CEMENTATION METHOD OF POST-CORE ON MICROLEAKAGE Myoung-Jae Yun, Sun-Hyoung Lee, Jae-Ho Yang Department of Prosthodontics, College of Dentistry, Seoul National University The restoration of the severely damaged teeth by post core have been increased with the developement of endodontic procedures But high failure rates of these procedures being reported, various restorative modifications were induced for successful treatments Cast post-core and prefabricated post with core buildups are choice of treatment The main causes of failure of the restorations are the fracture of post and core, root fracture, and recurrent caries due to microleakage Recently, the acid etching technique and the use of dentin bonding agent at tooth surface to reduce the possible microleakage at the tooth-restoration interfaces were introduced The object of this study was to measure and compare the microleakage by the types and cementation methods of post-core For this study, forty extracted human anterior teeth were selected for specimen After cleansing and routine endodontic procedures, anatomic crowns of each specimen were removed at the level of 2mm above the cementoenamel junction Canals were preparated for post insertion and specimens were divided into four groups randomly Post-cores were fabricated according to method for each group Microleakage was measured by length of dye penetration at the tooth-restoration interfaces with measuring microscope at 50 magnification Oneway ANOVA and t-test were performed for statistical analysis of resulting data The following results were obtained from this study 1 There were significant statistical differences in degree of microleakage between each group(p<001) 2 Cast post-core cemented with ZPC(Group Ⅰ)showed the most severe microleakage pattern(15547±00872mm), and cast post-core cemented with adhesive resin cement after tooth surface treatment with dentin bonding agent(group Ⅱ)showed the least microleakage(01497±00872mm) 3 Group Ⅳ revealed less dye penetrations than group Ⅲ, but no statistical significance was seen between two groups Key word : post core, microleakage 233