대한소아치과학회지 35(3) 2008 수종의불소함유수복재의불소유리및압축강도에관한연구 박지영 * 김종수 * 김승오 ** 단국대학교치과대학 * 소아치과학교실, ** 치과마취학교실 국문초록 본연구는새로개발된레진강화형글래스아이오노머인 Ketac N 100과 Fuji Fil LC의개선된점을보기위해불소유리량과압축강도를 Fuji II LC와비교평가해보았다. 불소유리량측정을위해각재료별로시편을 15개씩제작하여탈이온수에보관하였고, 31일동안 ph/ise meter(750p, Istek, Korea) 를이용하여불소유리량을측정하였다. 압축강도측정을위해각재료별로 15개씩시편을제작하여만능경성시험기 (Kyung-sung Testing Machine Co., Korea) 를이용하여시편이파절된시점의최대강도를측정하였다. 연구결과얻은결론은다음과같다. 1. 전반적인불소유리량은 Fuji Fil LC, Fuji II LC, Ketac N 100 순으로높았다 (p<0.05). 2. 압축강도는 Fuji II LC와 Ketac N 100은유의한차이가없었고 (p>0.05), Fuji Fil LC는두재료보다낮은압축강도값을보였다 (p<0.05). 이상의결과를종합해보면 Ketac N 100은대조군인 Fuji II LC와비교시불소유리량은적었으나압축강도는유사했고 Fuji Fil LC는불소유리량은높았고압축강도는낮았다. 이런재료의특성에맞게임상적용을하는것이중요할것이다. 주요어 : 불소유리, 레진강화형글래스아이오노머의강도 Ⅰ. 서론글래스아이오노머는 1969년개발되어 1970년대초에 Wilson과 Kent 1) 에의해보고되었다. 글래스아이오노머는치질에화학적결합을하고, 불소를방출하여이차우식에저항성을갖게하는등의장점이있어오랫동안소아치과영역에서수복재로사용되어져왔다 2). 그러나전통적인글래스아이오노머는경화의초기과정에서수분에노출될때, 마모에대한저항성과강도가크게저하된다 3). 이러한문제점을극복하기위해레진성분을가미한레진강화형글래스아이오노머가 1990년대초개발, 시판되었다. 레 진강화형글래스아이오노머는광중합반응으로초기강도가결정되므로글래스아이오노머의단점이었던수분민감도가광중합이후감소하고, 초기에높은표면강도를얻을수있다 4,5). Forss 등 6) 에의하면불소유리는주변치아조직의탈회를막을뿐아니라치태내의 Mutans streptococcus에대한항균작용도지니고있다 7). 이런효과는레진강화형글래스아이오노머에서도나타나는데, 불소를유리하고재흡수하는능력은전통적인글래스아이오노머와비슷하거나더높다고하였다 8-10). Crisp 등 11) 에의하면글래스아이오노머기질안에서교차결합은증가하기때문에시간경과에따라압축강도는증가하지만취약하고인장강도가낮으며낮은마모저항성을가지고있기 교신저자 : 김종수 충남천안시안서동산 29 / 단국대학교치과대학소아치과학교실 / Tel: 041-550-1931,1932 / E-mail: jskim@dku.edu 원고접수일 : 2008 년 3 월 17 일 / 원고최종수정일 : 2008 년 5 월 22 일 / 원고채택일 : 2008 년 6 월 04 일 469
J Korean Acad Pediatr Dent 35(3) 2008 때문에높은압력을받는구치부에서는적합하지않다고하였다 12). 반면레진강화형글래스아이오노머는레진성분이첨가되어전통적글래스아이오노머에비해압축강도가증가하였다 13). Williams와 Billington 14) 은압축강도만을보면구치용으로사용할수있는지여부를알수있다고하였다. 본연구는최근새로개발된재료인 Fuji Fil LC와 Ketac N 100의불소유리량과압축강도를기존에시판되고있는 Fuji II LC와비교하여이차우식억제효과및적절한임상적용가능성을평가하고자시행하였다. Ⅱ. 연구재료및방법 광도를유지하기위해 Radiometer (Dent-America, USA) 를사용하여 10회마다한번씩반복측정하여조사하였다. 2. 연구방법 (1) 불소유리량비교실험 1) 시편제작시편제작을위해내경 6 mm, 높이 1 mm공간을형성한철판몰드를사용하였다. 몰드에시료를채운후 Mylar strip과유리판을개재한상태에서양면에 20초씩광중합을시행하였다. 각재료마다 15개씩총 45개의시편을제작하였다. 1. 연구재료심미성개선을위해 nanofiller를첨가한 Ketac N 100(Light-curing Nano-ionomer Restorative, 3M ESPE, USA) 과불소유리량을증진시킨 Fuji Fil LC(Light-cured Glass Ionomer Restorative, GC Co, Tokyo, Japan) 를실험군으로하고대조군으로 Fuji II LC(Light-cured Glass Ionomer Restorative, GC Co, Tokyo, Japan) 를사용하였다. 실험재료에따라 Table 1과같이 3개의군으로나누었으며각군당 15개의시편을제작하여연구에적용하였다. 광중합기는 Elipar Freelight(3M ESPE, USA) 를사용하였고, 일정한 2) 불소유리량측정 3 ml탈이온수를채운폴리에틸렌튜브에시편을넣어처음 7일간은 1일간격으로, 이후부터 31일까지는 3일간격으로불소유리량을측정하였으며, 보관하는동안하루에한번씩시편을흔들어주었다. 3일간격으로불소유리량을측정한경우에는그값을 3으로나누어기록하였다. 각시편은유리된불소량측정기간동안에매일새로운탈이온수로교환해주었다. 불소유리량측정은폴리에틸렌튜브에서시편을꺼낸후동량의 TI- SAB II(Total Ionic Strength Adjusting Buffer, Istek, Korea) 용액을첨가하여잘섞은다음 ph/ise meter(750p, Istek, Korea) 에부착된불소전극 (Fluoride combination electrode, Istek, Korea) 을사용하여각각의용액내에유리 Table 1. Materials used in this study and sample grouping Group Material Composition Manufacturer N De-ionized water Blend including HEMA I Ketac N 100 Metacrylate modified polyalkenoic acid 3M ESPE, USA 15 Fluoroaluminosilicate glass Nanomers and Nanoclusters Alumino-silicate glass 2-Hydroxyethyl methacrylate Urethanedimethacrylate II Fuji Fil LC Distilled water GC Co, Tokyo, Japan 15 Polyacrylic acid Urethanedimethacrylate Silicone dioxide Silica powder Polyacrylic acid 2-Hydroxyethyl methacrylate III Fuji II LC proprietary ingredient GC Co, Tokyo, Japan 15 2,2,4 trimethyl hexamethylene - dicarbonate triethylene glycol - dimethacrylate alumino-silicate glass *N= number of specimen 470
대한소아치과학회지 35(3) 2008 된불소농도를측정하였다. 매측정시마다측정에앞서측정할용액과같은온도에서 0.1 ppm, 1 ppm, 10 ppm의불소표준용액 (Fluoride standard solution, Istek, Korea) 으로농도보정과정을시행하였다. 3) 통계분석각각의재료에따른기간별불소유리량을 SPSS Ver 15.0 프로그램을이용하여, One-way ANOVA test로유의성을검정하고 Scheffe test로사후검정을시행하여통계분석하였고, 실험경과시간에따른불소유리양상을회귀분석하였다. (2) 압축강도비교실험 1) 시편제작내경 3 mm, 높이 4 mm의아크릴주형을이용하여재료를채운후제조사의지시대로광중합을양쪽면에서시행하였다. 중합을완료한후, 37 의 100% 상대습도에서 24시간동안보관하였다. 각재료마다 15개씩총 45개의시편을제작하였다. 2) 압축강도측정각군시편의압축강도를측정하기위해서만능시험기 (Kyung-sung Testing Machine Co., Korea) 를이용하여분당 5 mm의속도로압축하중을가하여최대하중 (kg) 압력을가한후시편이파절된시점의강도를측정하였다. 3) 통계분석각각의재료에따른압축강도를 SPSS Ver 15.0 프로그램을이용하여, One-way ANOVA test로유의성을검정하고 Scheffe test로사후검정을시행하여통계분석하였다. Ⅲ. 연구성적 1. 불소유리량측정결과 Table 2, 3, 4는각군의측정일에따른불소유리량을나타낸결과이고, Fig. 1은측정일에따른불소유리량의변화를나타낸도표이다. 불소유리량은모든군에서첫째날유리량이 Table 2. Daily fluoride release from 1 to 5 days (Mean ± SD) Unit: ppm Group Day 1 Day 2 Day 3 Day 4 Day 5 Ⅰ Mean 3.916 1.764 1.605 1.578 0.878 SD 0.203 0.134 0.094 0.437 0.040 Ⅱ Mean 6.941 4.119 3.502 2.329 2.121 SD 0.418 0.404 0.277 0.188 0.158 Ⅲ Mean 2.860 1.070 0.737 0.674 0.512 SD 0.542 0.180 0.114 0.196 0.078 Table 3. Daily fluoride release from 6 to 16 days (Mean ± SD) Unit: ppm Group Day 6 Day 7 Day 10 Day 13 Day 16 Ⅰ Mean 0.910 0.890 0.763 0.679 0.490 SD 0.072 0.099 0.050 0.034 0.050 Ⅱ Mean 1.533 1.412 1.162 1.165 1.160 SD 0.161 0.125 0.075 0.058 0.095 Ⅲ Mean 0.523 0.501 0.395 0.361 0.222 SD 0.073 0.069 0.020 0.019 0.024 Table 4. Daily fluoride release from 19 to 31 days (Mean ± SD) Unit: ppm Group Day 19 Day 22 Day 25 Day 28 Day 31 Ⅰ Mean 0.504 0.470 0.464 0.480 0.306 SD 0.024 0.022 0.018 0.036 0.016 Ⅱ Mean 0.813 0.719 0.749 0.815 0.793 SD 0.047 0.045 0.073 0.100 0.119 Ⅲ Mean 0.247 0.216 0.198 0.206 0.149 SD 0.027 0.025 0.023 0.021 0.017 471
J Korean Acad Pediatr Dent 35(3) 2008 Fig. 1. Daily fluoride release(ppm) over 31 days. Fig. 2. Comparison of regression line among 3 materials. Fig. 3. Cumulative fluoride release over 31 days. Table 5. The mean compressive strength (kg/cm 2 ) Group Mean value with standard deviation(kg/cm 2 ) Ⅰ 1751.83 ± 115.23 a Ⅱ 1340.61 ± 184.03 b Ⅲ 1713.00 ± 312.34 a Values in columns having the same letter were not significantly different (P>0.05) 가장높게나왔으며둘째날부터급격히감소했고 7일이후부터완만한유리량을보였다. 통계결과모든측정기간동안불소유리량이 Fuji Fil LC, Fuji II LC, Ketac N 100 순으로유의하게높았다 (p<0.05). Fig. 2는회귀분석을통해나타낸도표이며, 재료간불소유리양상이모두유의한차이를보였으며, Fuji Fil LC에서가장급격한불소유리량감소가나타났고, Fuji II LC가가장완만한불소유리량감소를보였다. Fig. 3은 31일동안유리된불소의축적된양을나타낸다. 2. 압축강도측정결과 Table 5는압축강도의평균값을나타낸결과이다. Ketac N 100과 Fuji II LC간에는통계결과유의한차이가없었고, Fuji Fil LC는나머지두재료에비해압축강도가유의하게낮았다 (p<0.05). 472
대한소아치과학회지 35(3) 2008 Ⅳ. 총괄및고안레진강화형글래스아이오노머는폴리아크릴릭산, 광중합단량체인 HEMA, 레진성분인 Bis-GMA, 불소이온과나트륨이온과같은이온유출이가능한유리분말및물등으로구성되며초기경화반응은레진성분과의광중합반응이고서서히산- 염기반응을진행한다 15,16). 광개시중합과산-염기반응의이중경화기전으로중합하여서로의반응을보완하고있는데, 광개시중합반응은강도와용해저항성을증진시키고산-염기반응은재료와치아구조사이의결합력을증진시키며불소를지속적으로방출하게한다 17-19). 또한레진강화형글래스아이오노머는글래스아이오노머의장점인생체적합성, 치질과유사한열팽창계수, 치질에물리화학적으로결합하는성질은유지한다 20). 우식활성도가높은소아환자에서구강수복물의실패가높은빈도로나타나는데, 여러문헌을살펴보면구강내수복물이실패하는원인중가장흔한원인은이차우식이다 21-23). 1987년 Klausner 등 24) 은 5511개의아말감수복환자중 53 % 가이차우식이생겨다시치료받으러내원하였다고보고하였다. 수복물의성패를좌우하는요소로는수복재가이차우식에저항하는능력과변연봉쇄능력이다 25). 그러나여러연구에서변연봉쇄능력도중요하지만, 수복재의항우식작용이이차우식에밀접한연관을가진다고보고하였다 26,27). 수복재의항우식작용은불소를유리하는능력에서기인하고치면에대한불소의적용효과는수산화인회석구조를불화인회석구조로변화시켜내산성이증가되고, 미생물의효소생성억제및항균작용등을나타낸다 8,28-30). 글래스아이오노머의불소유리에관한문헌을살펴보면글래스아이오노머는불소를유리할뿐아니라불소를재흡수하여다시방출하는특성을지닌다 31,32). 글래스아이오노머의불소유리양상은 Diaz-Arnold 등 33) 과 Grobler 등 34) 에의하면처음 24시간동안가장높게나타나고 7일이경과된후에급격한감소를보인다고하였다. Verbeeck 등 35) 의연구에따르면불소유리양상은두단계로나누어볼수있다. 첫번째단계에서는짧은시간동안빠르게불소유리가일어나고, 두번째단계에서는오랜시간동안점진적이고지속적인불소유리양상을보인다고보고하였다. 본연구에서도처음 24시간동안불소유리량이가장높았고 7일이후부터낮은농도의불소를지속적으로유리하는양상을보였다. 레진강화형글래스아이오노머는전통적글래스아이오노머보다불소유리량이더많은데이것은유기물질과이량체기질의존재로인해산-염기반응이더느리게일어나서이온기질이전통적글래스아이오노머보다상대적으로성글기때문이라고하였다 36,37). 불소재흡수능력에대해서도여러문헌에서레진강화형글래스아이오노머가전통적글래스아이오노머보다뛰어나다고보고하였다 8,31,33,34). 본연구에서는이전문헌에서비교적양호한불소유리능력 을보였던 Fuji Ⅱ LC를새로출시된레진강화형글래스아이오노머인 Fuji Fil LC와 Ketac N 100과비교하였는데, Fuji Fil LC는 Fuji Ⅱ LC에비해뛰어난불소유리능력을보여주었고, Ketac N 100은상대적으로낮은불소유리를보였다. Ketac N 100은 nanofiller를첨가하여복합레진에비해떨어지는레진강화형글래스아이오노머의심미성개선에중점을둔재료이기때문에다른재료에비해불소유리량이적은것으로사료된다. 반면 Fuji Fil LC는불소유리가강화된제품으로우식활성이높은환아에서사용시이차우식예방에좋은효과를낼것으로사료된다. 전통적글래스아이오노머는낮은물리적성질때문에와동이큰경우, 특히 1급,2급,4급와동에서는그사용이제한된다고하였다 38). 레진강화형글래스아이오노머는전통적글래스아이오노머의압축강도보다 2.5배높다고하였고이는광중합형레진의강화로시멘트기질의인성은증가하고취성파괴를감소한결과라고하였다 13). 임상적으로연구한문헌에서레진강화형글래스아이오노머를유구치 2급와동에적용했을때, 아말감과비교시실패율은유의한차이가없었다 39). 이는레진강화형글래스아이오노머의항우식효과와증진된강도의결과라고생각할수있다. 그밖의레진강화형글래스아이오노머의물리적인성질을살펴보면, 적절한와동봉쇄능력이보고되었고 40,41), Triana 등 42) 은전통적글래스아이오노머보다열순환후에치아구조에대한결합력이높다고하였다. 본연구에서대조군으로사용한 Fuji Ⅱ LC의압축강도는다른연구와유사한결과를나타내었다 13). Fuji Ⅱ LC와비교시 Ketac N 100은유사한압축강도값을얻었고 Fuji Fil LC는두재료보다압축강도가떨어졌다. 실험과정중에서도재료를철판몰드에서분리시킬때 Fuji Fil LC는몇개의시편이깨져나가는양상을보였다. 그러나 Fuji Fil LC의압축강도는김과임 13) 의연구결과와비교시전통적글래스아이오노머의압축강도보다 2배높게나타났다. Ketac N 100은불소유리량은낮았지만압축강도는대조군과유사한결과를보여주었고, 실험과정에서육안으로관찰시투명도가높다고느꼈다. 따라서심미성이요구되는유전치에사용하기에적합할것으로사료된다. Fuji Fil LC는압축강도는낮았지만불소유리량이월등히높았으므로우식활성이높은환아에서 Base 재료나교합력이낮은부위에서수복재로사용하기에적합할것이다. 이런재료의특성을잘파악하여임상에서적절히사용하는것이무엇보다도중요할것이다. 본연구의한계점은 Fuji Fil LC의첫째날불소유리량이기존제품에비해월등히높았기때문에불소유리양상을관찰하기에는 31일이짧았다고생각된다. 좀더긴시간동안불소유리양상을관찰하여첫째날불소유리량이높은재료가불소유리에어떤장점을가지고있는지추가적인연구가필요하다고사료된다. 또한각재료의심미성평가를위한광택도와투명도에관한연구, 구강환경을재현하기위해열순환을거치 473
J Korean Acad Pediatr Dent 35(3) 2008 거나 6개월이상증류수에보관후측정한압축강도, 실제임상적용시치료성공률에대한추가연구가필요할것으로사료된다. Ⅴ. 결론본연구는새로개발된레진강화형글래스아이오노머인 Ketac N 100과 Fuji Fil LC의불소유리량과압축강도를 Fuji II LC와비교평가해보기위해시편을제작하여불소전극 (Fluoride combination electrode, Istek, Korea) 과만능경성시험기 (Kyung-sung Testing Machine Co., Korea) 를이용하여측정하였고, 그결과는다음과같다. 1. 전반적인불소유리량은 Fuji Fil LC, Fuji II LC, Ketac N 100 순으로높았다 (p<0.05). 2. 불소감소율은 Fuji Fil LC가가장급격하게나타났고, Fuji II LC는가장완만한감소율을보였다 (p<0.05). 3. 압축강도는 Fuji II LC와 Ketac N 100간에는유의한차이가없었고 (p>0.05), Fuji Fil LC는두재료보다낮은압축강도값을보였다 (p<0.05). 이상의결과를종합해보면새로개발된재료인 Ketac N 100은대조군인 Fuji II LC와비교시불소유리량은적었으나압축강도는유사했고 Fuji Fil LC는불소유리량은높았고압축강도는낮았다. 이런재료의특성에맞게임상적용을하는것이중요할것이다. 실제임상적용에서의치료성공률에대한연구와, 구강환경재현을위한보다다양하고발전된방법으로보완연구가필요할것으로사료된다. 참고문헌 1. Wilson AD, Kent BE : A new translucent cement for dentistry. The glass ionomer cement. Br Dent J, 132:133-135, 1972. 2. Crips S, Lewis BG, Wilson AD : Characterization of glass ionomer cements. The physical properties of current materials. J Dent, 12:231-240, 1984. 3. Um CM, Oilo G : The effect of early water contact on glass-ionomer cements. Quintessence Int, 23:209-214, 1992. 4. Mongkolnam P, Tyas MJ : Light-cured lining materials: a laboratory study. Dent Mater, 10:196-202, 1994. 5. Croll TP : Glass ionomers and esthetic dentistry: What the new properties mean to dentistry. J Am Dent Assoc, 123:51-4, 1992. 6. Forss H, Jokinen J, Spets-Happonen S, et al. : Fluoride and mutans streptococci in plaque grown on glass ionomer and composite. Caries Res, 25:454-458, 1991. 7. Loyola-Rodriguez JP, Garcia-Godoy F, Lindquist R : Growth inhibition of glass ionomer cements on mutans streptococci. Pediatr Dent, 16:346-349, 1994. 8. Forsten L : Resin-modified glass ionomer cements: fluoride release and uptake. Acta Odontol Scand, 53:222-225, 1995. 9. Momoi Y, McCabe JF : Fluoride release from lightactivated glass ionomer restorative cements. Dent Mater, 9:151-154, 1993. 10. Forss H : Release of fluoride and other elements from light-cured glass ionomers in neutral and acidic conditions. J Dent Res, 72:1257-1262, 1993. 11. Crisp S, Lewis BG, Wilson AD : Characterization of glass-ionomer cements. Long term hardness and compressive strength. J Dent, 4:162-166, 1976. 12. Hse KM, Leung SK, Wei SH : Resin-ionomer restorative materials for children: a review. Aust Dent J, 44:1-11, 1999. 13. 김철위, 임범순 : 글라스아이오노머시멘트와콤포짓트레진복합체의물성에관한연구. 대한치과기재학회지, 22:29-46, 1995. 14. Williams JA, Billington RW : Increase in compressive strength of glass ionomer restorative materials with respect to time: a guide to their suitability for use in posterior primary dentition. J Oral Rehabil, 16:475-479, 1989. 15. Burgess J, Norling B, Summit J : Resin ionomer restorative materials, The new generation. J Esthet Dent, 6:207-215, 1994. 16. Nicholson JW, Anstice HM : The physical chemistry of light-curable glass ionomer. J Mater Sci Mater Med, 5:119-122, 1994. 17. Wilson AD : Resin-modified glass-ionomer cements. Int J Prosthodont, 3:425-429, 1990. 18. Mitra SB : Adhesion to dentin and physical properties of a light-cured glass-ionomer liner/base. J Dent Res, 70:72-74, 1991. 19. Sidhu SK, Watson TF : Resin-modified glass ionomer materials. A status report for the American Journal of Dentistry. Am J Dent, 8:59-67, 1995. 20. Croll TP, Nicholson JW : Glass ionomer cements in pediatric dentistry, review of the literature. Pediatr Dent, 24:423-429, 2002. 21. Varpio M : Clinical aspects of restorative treatment in the primary dentition. Swed Dent J, 96:36-40, 1993. 474
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J Korean Acad Pediatr Dent 35(3) 2008 Abstract COMPARATIVE STUDY ON THE FLUORIDE RELEASE AND COMPRESSIVE STRENGTH OF SEVERAL F-CONTAINING RESTORATIVE MATERIALS Jee-Young Park*, Jong-Soo Kim*, Seung-Oh Kim** *Department of Pediatric Dentistry, **Department of Anesthesiology, School of Dentistry, Dankook University This study was performed to compare the fluoride release pattern and compressive strength of recently developed resin-modified glass ionomers(ketac N 100 and Fuji Fil LC) with those of conventional glass ionomer restorative material(fuji Ⅱ LC). Fifteen sample discs(6 mm diameter and 1 mm height) were prepared for each tested material. The fluoride release was measured by ph/ise meter(750p, Istek, Korea) for 31 days. For compressive strength experiment, fifteen cylindrical specimens were prepared for each tested material. Each specimen was submitted to compressive strength testing in an universal testing machine(kyung-sung Testing Machine Co., Korea) at crosshead speed of 5.0mm/min until failure. The results can be summarized as follows; 1. Fuji Fil LC released the highest amount of fluoride, followed by Fuji Ⅱ LC and Ketac N 100(p<0.05). 2. The compressive strength of Fuji Fil LC was the lowest(p<0.05). However, no significant difference was found from Fuji II LC and Ketac N 100(p>0.05). By considering the above results, careful case selection and accurate clinical application is recommended when using Ketac N 100 and Fuji Fil LC. Key words : Fluoride releasing, Strength of resin-modified glass ionomer 476