대한치과보철학회지 :Vol. 38, No. 1, 2000 복합레진의표면조도에관한연구 순천향대학교의과대학치과학교실보철과 박기현 Ⅰ. 서론생활수준의향상과더불어치과환자의심미에대한요구가증가되고있다. 이와같은심미에대한요구와복합레진의발달에힘입어복합레진의임상적인적용은최근치의학분야에

대한치과보철학회지 :Vol. 38, No. 1, 2000 복합레진의표면조도에관한연구 순천향대학교의과대학치과학교실보철과 박기현 Ⅰ. 서론생활수준의향상과더불어치과환자의심미에대한요구가증가되고있다. 이와같은심미에대한요구와복합레진의발달에힘입어복합레진의임상적인적용은최근치의학분야에서지대한관심의대상이되고있다. 특히심미성, 접착성, 간편한임상술식의장점을가지고있기때문에 1962년 Ray Bowen이 Bis-GMA형태의복합레진을개발한이래로다양한형태와종류의복합레진이도재수복물과함께보철, 보존, 교정분야에서광범위하게사용되고있다. 그러나복합레진은무기질 filler와레진기질간의경도차이로인해활택한표면을얻기어렵다 1). 활택한면은만족스런수복물을얻기위한필수적인요건중의하나로서거친면은음식물잔사나치태의침착을야기하며, 치은염증, 치아경조직의이차우식을초래하고수복물의색조변화를가져와결과적으로수복물이실패하게된다. 복합레진의연마방법은복합레진의개발과연마기구, 연마방법의향상에따라다소의차이점을나타내고있다. 1970년대 Marcrofill복합레진시기에는텅스텐카바이드바, 다이아몬드디스크, 씰리콘카바이드디스크, white stone, silicone rubber, white aluminum point 등 6,8,9,13-18) 이우수한결과를보인다고보고되었다. 1978년 microfill복합레진이개발된이후에는 aluminumoxide disc가활택한표면을얻는데적절하다고보고한연구들이많았으며, hybrid 복합레진의경우에서도 aluminum-oxide disc로연마한면이활택했으며 19-25), 연마기구뿐아니라연마재로서 polishing paste 의효용성을부각시킨연구들도있었다 26,27). 통상적으로복합레진의표면조도에관한연구방법으로는 profilometer를이용하여정량적으로계측하는방법 6,7,16,25,27) 이있고주사전자현미경을이용하여표면의성상을분석하는방법 1-4,8,9,11-13,19-21,33,35) 이이용되어왔다. 또한위의두방법을동시에시행하여정량적인면뿐만아니라, 정성적인면에서도비교관찰한연구들 6,7,10,14,15,17,18,22,32) 도많이시도되어왔다. 본연구에서는표면조도기 Surfcoder SEF- 30D(Kosaka lab. Ltd) 를사용하여연마시행에따른복합레진의표면조도에대해서비교연구하여다음과같은결과를얻었기에보고하는바이다. Ⅱ. 연구재료및방법복합레진은 Z100(3M Dental Products, U.S.A.) 를사용하였으며각군당시편을 5개씩제작하였다. 시편제작은두께 4mm의 vinyl plate에직경 4mm의구멍을형성하여유리평면위에놓고레진을복합레진충전기구 (GC, japan) 를사용하여충전하였으며, 충전후광조사기 (Visilux 2,3M Dental Products, U.S.A.) 로제조자의지시에따라서광중합하였다. 연마기구는 abrasive disc (3M Dental Products, U.S.A.) 를사용하였으며 Table 1 과같은군으로구분하여시행하였다. 표면조도의측정기계는 Surfcoder SEF-30D (Kosaka lab. Ltd) 를사용하였으며, 조도측정시의 108

Table 1. 연마에따른실험군의 Glass plate 군 (1 군 ) No polish 군 (2군) Disc polish 군 (3군) Bonding agent 군 (4 군 ) Celluloid 군 (5 군 ) : 레진충전기구로충전후 slide glass로지압하고광중합시킨군 ( 연마시행안함 ), : 레진충전기구로충전후광중합하고연마하지않은군 : 레진충전기구로충전및광중합후 abrasive disc로연마한군 : 레진충전기구로충전및중합후 abrasive disc로연마한후 bonding agent를바르고광중합한군 : 레진충전기구로충전후 Celliuloid crown으로지압하고광중합시킨군 ( 연마시행안함 ) cut off파장은 0.08mm, 측정길이는 0.8mm로하였다. 측정 stylus의속도는 0.05mm/s, 수평확대는 40 배수직확대는 5,000배로하였다. 측정은 Ra, Rt, Rmax, Rz 및 F-profile의 4가지항목으로각시편당 2회씩측정하였다. 이해를위해각측정값의개념은다음과같다. 1) 조도곡선 (F profile, Fig. 1) 단면곡선 (P profile) 에서표면의곡면을제거한곡선으로순수한표면조도를볼수있다. 2) 평균조도 (Ra : μm, Fig. 2) F-profile에서조도를평균선에적분한수치. 즉표면조도를두께로표현한것 3) Rt ( μm, Fig. 3 ) F-profile에서최대-최저값 4) Rmax ( μm, Fig. 4) P-profile에서최대-최저값 Fig. 1. 단면곡선과조도곡선 3000 Fig. 2. 평균조도 (Ra) Fig. 3. Rt ( μm ) Fig. 4. Rmax ( μm ) Fig. 5. Rz ( μm ) 109

5) Rz ( μm, Fig. 5) F-profile에서측정구간을 5등분하여각구간의 Rt의평균값 Ⅲ. 연구성적 이 5군 (0.017 0.019), 2군 (0.065 0.073), 4군 (0.065 0.125), 3군 (0.134 0.158) 순으로나타났다. 이중 4군의범위가가장넓었는데, 조도곡선 (Fprofile) 을관찰하면조도가다양한면이불규칙하게섞여있음을알수있다. 1. 조도곡선 (F-profile) 에의한평가 3. Rt 에의한평가 (Table 2, Fig. 7) 측정결과관찰된각군의조도곡선은 (Fig. 6) 과같다. 대조군인 slide glass 나 celluloid 에의해지압후중합시킨군 (1군과 5군 ) 이가장활택한표면으로관찰되며 disc에의해연마한군 (3 군 ) 이연마를시행하지않은군 (2군) 보다더불규칙한표면을나타내었고 disc에의해연마후 bonding agent를도포한군 (4 군 ) 도불규칙한표면을보여주었다. 육안으로평가시에도불빛에반사되는양이실험결과와유사하게나타났다. 한편 no polish군에서는육안으로관찰시얇은흰색의막이관찰되었는데, 이는산소억제층에의한것으로추정되어진다. 2. 평균조도에의한평가 (Table 2, Fig. 7) 순수표면조도값인 Ra 값을비교시에, 1군 (0.007 0.009) 이가장매끄러운것으로나타났으며, 그다음 연마정도를평가하는 Rt는전반적으로 Ra보다큰수치로나타났는데, 마찬가지로 1군이가장활택했고그다음으로 5군, 2군, 3군, 4군순으로 Ra 값과동일한순서로나타났다. Rt에서더확실해진것은 2 군이확실히 3군보다활택하다는점이었다. 4. Rmax에의한평가 (Table 2, Fig. 7) 가공정도를평가하는 Rmax는 1군 (3.2 3.3) 이가장우수했고나머지는비슷한수치 ( 약7 8) 를나타냈다. 1회측정시와 2회측정시의수치변화가크게나타났다. 이는표면에따라불규칙한면이많이섞여있음을의미한다. 5. Rz에의한평가 (Table 2, Fig. 7) 측정길이에서 Rt를 5회구하여평균값을구한 Rz 1 군 (Glass plate) 2 군 (No polish) 3 군 (Disk polish) 4 군 (Bonding agent) 5 군 (Celluloid) Fig. 6. 각군의조도곡선 (F-profile) 110

Table 2. 각군의 Ra, Rt, Rmax, Rz 및 F-profile 수치 1군 2군 3군 4군 5군 Ra 평균 0.007 0.073 0.146 0.095 0.020 표준편차 0.001 0.010 0.010 0.035 0.005 Rt 평균 0.123 0.647 1.708 0.969 0.250 표준편차 0.046 0.017 0.318 0.064 0.030 Rmax 평균 3.310 11.543 9.727 9.584 6.465 표준편차 0.056 2.280 0.655 1.651 1.526 Rz 평균 0.665 2.462 2.407 2.180 1.374 표준편차 0.012 0.275 0.064 0.353 0.276 Fig. 7. 각군의 Ra수치비교는 1군이가장우수했고그다음이 5군이었으며, 나머지는비슷한결과값을나타냈다. Ⅳ. 총괄및고찰이전연구 6,7) 에서복합레진수복물에서얻을수있는가장활택한표면은 matrix strip의사용으로가능하다고보고한바있으나임상적으로치아의해부학적인형태를재연해낼수있는matrix strip은존재하지않으며따라서형태재연을위해연마기구를사용한연마하는과정이필요하다고보고하였다본연구에서도 slide glass를이용한군이가장활택한레진표면을보였으며그다음이 celluloid를이용한군이었다. 특이한점은연마하지않고레진충전기구를사용해충전만한군이충전후연마한군보다통계적으로유의성있게레진표면의활택도가높게나타났다는것이다. 이것은과거의문헌보고에서도유사한결과가있었음을확인할수있었다. 이런현상은복합레진을연마하지않은경우레진의 matrix가 filler를둘러쌈으로써불규칙한 filler가표면에노출되지않기때문으로추측이되며, 표면을연마한경우는 filler를둘러싸는 matrix가벗겨짐으로써불규칙한 filler가노출되기때문인것으로사료된다. 이런결과를고려해볼때일반적으로레진충전후연마과정을시행하면표면이활택해질것이라는기존의개념이잘못되었을수있을의미한다. 이에대한과거의견해는레진을충전후잘못된외형을다듬어주어야하기때문에연마를해야함을지지하고있다. 그러나표면의보다높은활택도를위한다면, 복합레진의외형을가능한한완전히다듬은후에광중합하는것이바람직할것으로사료되며, 광중합후에는가능한연마부위를최소로하는것이보다바람직할것이다. 따라서 3급치아와동이나전치부순면의와동등에복합레진으로충전시중합전적절한형태를부여하여마무리를적게함으로써연마면적을가능한한최소화하는것이바람직하리라사료된다. 또한일부임상에서복합레진충전, 연마후표면활택을얻기위해 bonding agent를도포하기도하는데본실험결과일부는효과가있으나부분적으로덜활택한면이불규칙적으로발생함이증명되었다. van Dijkene 19) Ferreira 20) Louka 21) Lambrechts 22) Berastegui 25) 등은 aluminum oxide disc를사용한경우여러복합레진에서활택한표면을얻을수있었다고보고하였고본연구에서도연마시 abrasive disc를사용하였다. Chandler 등 13) 은 paper disc 에작은입자의 diamond 입자를붙인연마기구와 cuttlefish disc간의연마효과를비교한연구에서연마기구가갖추어야할조건에대해다음과같이기술하였다. 첫째, 복합레진표면에광택성을부여하여야 111

한다. 즉연마기구에의해형성된흠집들이가시광선의파장보다작아가시광선이산란보다는반사되어야한다. 둘째연마기구의입자가복합레진의 filler 입자보다단단해야한다. 셋째연마입자가연마기구표면에견고하게붙어있거나, paste형태로사용하야하는지의방법상의문제다. 넷째모든잔사와연마기구에서떨어져나온연마입자를빨리제거해야한다. 다섯째연마기구의표면상태가지속적으로연마를해도편평해야한다. 여섯째연마기구가어느정도유연성이있거나 mandrel에부착되어유연성을가져야넓은부분을힘을적게가하면서연마를할수있다고보고하였다. van Noort 등 35) 은 filler 입자크기와분포가복합레진의표면활택도에큰영향을미친다고했으며 filler 의입자크기에따라 large-particle, small-particle, microfine 복합레진으로분류하여 large-particle 복합레진의경우에는 aluminum-oxide disc인 Soflex disc, small-particle 복합레진인경우에는 polishing paste가더우수한연마면을형성하며, microfine 복합레진의경우에는 Soflex disc와 polishing paste 간의큰차이가없다고보고하였다. 본연구에서는복합레진의연마한것과연마하지않은군에대해표면조도를조사하였는데향후여러연마기구의종류에따른표면조도의차이와잇솔질등구강내환경에노출후표면조도의변화를관찰하는것이필요하리라사료된다. Ⅴ. 결론복합레진은심미적인수복방법의하나로많이이용되고있으나표면조도가연마방법에따라서크게영향을받으며특히연마가불충분한경우에는치태침착, 치은염증, 비심미적인수복물등을야기할수있다. 이에저자는연마에따른복합레진의표면조도를표면조도기 (Surfcoder SEF-30D) 를이용하여관찰, 분석한결과다음과같은결론을얻었다. 1. Glass plate로지압하면서광중합한군 (1군) 이다른군에비해표면조도가가장낮았다. 2. 광중합후연마하지않은군 (2군) 이광중합후 abrasive disc로연마한군 (3군) 보다표면조도가낮았다. 3. 연마후 bonding agent를도포한군 (4 군 ) 과광중합후 abrasive disc로연마한군 (3군) 은표면조도의차이를보이지않았다. 4. Celluloid crown을사용한군 (5 군 ) 은.glass plate 로지압하면서광중합한군 (1군) 과거의유사한표면조도를보였다. 참고문헌 1. Bauer JG, Caputo AA.:The surface of composite resin finished with instruments and matrices. J. Prosthet. Dent. 1983;50:35l- 357. 2. Weitman RT, Eames WS.:PIaque accumulation on composite surfaces after various finishing procedures. JADA. 1975;91:101-106. 3. Lui JI, Low T.:The surface finish of the new microfiii restorative materials. J. Oral Rehab. 1982;9:67-82. 4. Serio FG, Strassler HE, Litkowski LJ, Moffitt WC, and Krupa CM.:The effect of polishing pastes on composite resin surfaces. J. PeriodontoI. 1988;31:837-840. 5. Chan KC, Fuller JL, and Hormati AA.:The ability of foods to stain two composite resins. J Prosthet. Dent. 1980;43:642. 6. Dennison JB, and Craig RG.:Physical properties and finished surface texture of composite restorative resins. J.A.D.A, 1972;85:101-108. 7. Glantz PO, Larsson LA.:Surface roughness of composite resin before and after finishing Acta OdontoI. Scand. 1972;30:336-347. 8. Johnson LN, Jordan RE, Lynn JA.:Effects of various finishing devices on resin surfaces, J.A. D.A. 1971;83:-33l. 9. Mclundie AC, Murray FD.:Comparison of methods used in finishing composite resin - a scanning electron microscope study. J. Prosthet. Dent. 1974;31:163-171. 10. Dennison JB, Fan PI, Powers JM.:Surface roughness of microfilled composites. J.A.D.A. 112

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J.A.D.A. 1987;115:299-301. 34. Goldstein RE. : Finishing of composites and Iaminates. Dent. CIin. North America l989;33 :305-318. 35. Van Noort R. and Davis LG.:Surface finish of composite resin restorative materials. Br Dent. J. 1984;167:360-364. Reprint request to: Ki-Hyun Park D.D.S., M.S.D. Department of prosthodontics, College of Medicine Soonchunhyung University 657, Hannam-Dong, Yongsan-Ku, Seoul 140-743, Korea appleeye@hosp.sch.ac. kr 114

ABSTRACT A STUDY OF SURFACE ROUGHNESS OF COMPOSITE RESIN Ki-Hyun Park D.D.S., M.S.D. Department of prosthodontics, Department of Dentistry, College of Medician, Soonchunhyung University This study was designed to compare the effect of polishing on surface roughness of composite resin. We used Z100(3M) composite resin and placed the composite resin in the hole (4mm thick and 4mm in diameter) of vinyl plate and polymerized it under manufacturer s instructions. Samples were divided into 5 groups by polishing methods. Group 1 was control: resin was polymerized under glass plate, Group 2: resin was polymerized without any polishing procedure, Group 3: resin was polymerized with a polishing procedure of abrasive disc, Group 4: bonding agent was applyed in thin layer and polymerized on the polished polymerized resin surface, Group 5: resin was polymerized under transparent celluloid strip. The surface roughness of each specimen was measured with Sufacoder SEF-30D (Kosaka lab. Ltd) under 0.08mm cut off, 0.05mm/s stylus speed, 40 horizontal magnification, 5000 vertical magnification. The results were as follows : 1. Group 1 showed the most smooth surface in this study. 2. Group 3 showed more rough surface than Group 2. Considering the surface roughness, it would be better to make the shape completely before polymerize the resin. To finish and polish after the polymerization of resin makes less smooth surface. 3. When we use the transparent celluloid strip, minimum finishing procedures are recommended. Any polishing procedure could not recover the smooth resin surface of celluloid strip. 4. Application and polymerization of the thin layer of bonding agent on the polished surface showed the minimum surface smoothing effect. 115