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1 - 대한치과보철학회지 Vol. 34 No. 1, 부분무치악환자에서기능하중노출이골유착성임플란트주위의치조골소실에미치는영향에관한방사선학적연구 연세대학교치과대학보철학교실 양순봉ㆍ한동후ㆍ양자호 I. 서론 Brånemark 임플란트가완전무치악환자에처음시술된후 30여년간임상에서널리이용되고있다. 초기에는골유착개념에관한가설과이를입증하는많은연구가진행되었으며 (6, 12, 13) 이후구강내식립된임플란트의성공여부를판단하기위한객관적인평가기준을세우기위하여임상연구가계속이루어졌다 년 NIH-Hazard Consensus (60) 에서는임플란트의 Benefit and risk 를주제로골유착성임플란트를제외한여러종류의임플란트에관하여논의되었는데임플란트성공의기준에대한언급과임플란트는 5년간 75% 가지속되어야한다고언급되었으며 Schnitman 과 Schlman (6) 은그들의연구에서최초로 5개항목으로이루어진임플란트성공기준을언급하였으나이러한기준들은과학적인연구자료가부추난상태였다. 1986년 Albrektsson, Zarb, Wington과Erin (7) 이임플란트의체계적인성공기준을발표하였다. 첫째, 임상적으로개개의임플란트는동요도가없어야하며둘째, 방사선사진상임플란트주위에어떤방사선투과상도없어야하며세째임플란트시술 1년후부터는연간수직골소실량이 0.2 mm이하가되어야하고네째, 동통, 감염, 신경학적장애, 하치조신경관의침범등지속적이고비가역적인증상들이없어야한다고하 였다. 1977년부터 1989년까지발표된논문들을분석한결과 (5) 임플란트의성공에대한광범위한기준으로동통, 강한고정, 탐침깊이, 골소실, 출혈지수, 임플란트주위의염증반응, 타진, 방사선학적평가를제시하고있다. 이들논문에서는 Silness와 Loe의치은지수, 치태지수를사용하였고일부논문에서는 Discomfort 라는주관적항목을조사하였으며 환자의만족도 를언급하기도하였고대부분동요도와방사선사진분석에의한생존률을발표하였다. James (30) 는부착력이약한접합상피가임플란트와골상반연조직사이에존재하므로치아주위보다임플란트에서변연골에더쉽게탐침될수있다고하였고 Schnittman (56) 등은치주낭탐침기사용을권장하였으며 Bergman등 (9) 은골유착성임플란트의상태를측정함에있어서치은지수, 치태지수, 탐침깊이를이용하고보철물의교합, 심미성도평가하였으며, 방사선검사로는임플란트와의계면에간극의존재여부를조사하였다. Lekholm (4) 등은골유착된임플란트에서는 2-6 mm의치주낭깊이를가지며부분무치악에서는주변치아보다임플란트주위에큰치주낭깊이를나타낸다고하였다. Misch (15) 는풍융한임플란트상부구조로인해탐침이곤란하며출혈지수가임플란트성공여부에관해자연치만큼신뢰도가없다고하고, Cox (38) 등은치은지수, 출혈지수와 70

2 같은치주조직을평가하는지수는불표요하다고까지하였다. 또한탐침깊이는임플란트식립전에존재하던국소적인질환의유무와기존의조직두께와연관을갖으며그러나아직합리적이고과학적인기준이없는상태에서쉽게관찰되며임플란트주위치은의염증상태를말해주고조직성상, 출혈, 삼출물, 변연골의변화여부를감지하는데이용되고있으나 (69) 이러한검사가약한부착구조에손상을줄수있고술자에따라, 숙련도에따라상이한결과를가져올수있다. 방사선학적검사도임플란트의건강도측정에이용되는중요한진단척도중하나다. Adell등 (3), Quirynen등 (53), Jemt등 (37), Fugazzotto등 (21), Gotfredson (23) 의 Smith등 (68) 의연구에서 Brånemark 임플란트를대상으로하여수술후의골소실량을방사선사진을이용하여조사한연구들을발표하였다. 이들은초기 1년간적게는 0.6 mm부터많게는 1.9 mm 의골소실을보이고 1 후부터는매년 0.05 mm에서 0.2 mm의골소실을보인다고하였으나방사선사진의한계성과함께임플란트는실제치아의위치보다하방에심겨진경우가많아근육의위치관계로인해평행한치근단방사선사진을얻기가어렵고이렇게왜곡된방사선사진에서는치조골소실여부에대한해석이어렵게된다. 치조골의변연부는치밀골이므로해면골이 40% 이상감소되어야방사선사진으로변화를감지할수있기때문에임플란트주위에방사선투과상이관찰되지않는다고하여임플란트와골사이의계면에반드시골조직이있다고할수는없다 (22). 따라서변연골의조기상실은임플란트치경부의응력에대한증거로써임플란트의협측에발생하나방사선사진상에는근심과원심부위만관찰되고, 설측과구개측은두껍고높은치조골능이위치하므로임상적인문제에대한초기표시로써임플란트건강도를판정하는것은매우어려운방법이다. 또한골변화가미세하게진행되기때문에노출조건, 현상과정에서발생하는명도대비의차이, 촬영의재현성을얻기힘들다는이유로그신뢰도가낮다. 그러나 Ziedses des plantes (77) 가개발한 subtraction radiograph 방법을 Jeffcoat (31, 32, 33), Wenzel (72) 등이치과치료에처음도입하여치주조직의변화를평가하는데널리쓰이고있으며, Brägger (10, 11) 는컴퓨터를이용한 digital subtraction 방법으로임상과연구에서임플란트에이용하고있다. 기존의임플란트가완전무치악에주로시술된반면최근에는부분무치악의치료에더많은임플란트가이용되고있고 (43, 73), 이에대한성공률도무치악경우와유사하게보고되고있으나비교적단기간동안의연구결과이고아직도위험성이지적되고있으며 (49) 골조직의형태와질이상이하고섭취하는음식물의종류와저작습관이서양인과다른국내에서의연구자료가미비한상태이다. 본연구의목적은서양인과조건이상이한우리나라환자, 특히부분무치악환자에서저작기능노출이골유착성임플란트주위치조골에미치는영향을알아보기위하여연세대학교치과대학치과병원에내원하여임플란트를시술받은은부분무치악환자에서보철물연결시부터정기적으로촬영된구내방사선사진으로디지탈방법 (26) 을이용하여보철물장착후 2년간의치조골변화를관찰하여다음과같은결과를얻었기에이를보고하는바이다. II. 재료및방법가. 재료 1991년 6월부터 1994년 12월까지연세대학교치과대학치과병원에내원하여임플란트보철치료를시행한부분무치악환자를대상으로하였다 (Table 1). 임플란트란 Brånemark system (Nobelpharma, Gotenberg, Sweden) 과 IMZ system (Friatec, Mannheim, Germany) 을이용하였다. 특이한전신질환이없는 18세부터 66세까지의환자로평균연령은 48.3세이었다. 보철술식및정기적검진은숙련된술자 1인에의해일관적으로시행되어술자간의유의차를최소화하려고노력했으며검진시전문가에의한치태조절및구강위생교육을시행하여양호한구강내상태를유지하도록도왔다. 또한출자의판단에의해환자의식이종류, 저작방식, 근육양상, 습관등을고려하여교합면재료를선택하고정기적인내원시마다비정상적인기능여부및교합에대한평가를시행하였고 71

3 이같이환자의경우는취침시교합안정장치를제작하여장착하도록하였다. 1 차수술시자가골이식및상악동거상술을이용하여임플란트를식립한경우는연구대상에서제외하였다. 본연구에는보철물장착시, 12 개월후및 24개월후에정기적인검진시내원하여구내방사선사진을촬영한환자중누락된측정값 (missing value) 이없는 37개임플란트에한정하였다. 나. 연구방법정기적검진을위해내원시, 보철물을장착한시점을기준으로하여 12개월후, 24개월후에촬영한구내방사선사진을이용하였다. 1) 방사선사진의디지탈이미지화 (Digitalization) 방사선사진을 slide 입력가능한 slide scanner(polaroid Co., Massachusetts, U.S.A.) 를이용하여해상도 1018 dpi, 256 gray scale로입력한후, 개인용컴퓨터 (486 DX2 IBM호환 ) 에서 computer graphic design분야에서이용되는 Adobe photoshop(adobe Co., version 2.51) 을이용하여각각의방사선사진을디지탈이미지화하였다. 임플란트의치조골높이로기준을설정하였다.(Fig. 1, 2) Brånemark 임플란트에서는연마된치경부의상부를기준점으로하고 IMZ 임플란트에서는방사선사진에서방사선투과성으로판독이용이한임플란트와내부가동성가구 (Polyoxymothylene Intra Mobile Element) 간의경계부를골계측의기준점으로설정하고각방사선사진에서이렇게설정된두점을프로그램상의도구를이용하여디지탈이미지상에표시하였다. 3) 치조골소실의계측방사선사진의특성상확대, 축소를감안하여이미알려진기준점을각각설정하여비례식으로계산하였다. Brånemark system에서는임플란트의연마된치경부 (1.00 mm) 를기준으로하였고 IMZ system에서는각임플란트의직경 (3.30또는 4.00 mm) 을기준으로하였다 ( 그림 1, 2). 치조골소실부위로설정된두점간의거리측정은 Borland사의 Turbo-C 프로그램을이용하여임플란트근, 원심면의치조골소실을계측하였다. 4) 통계처리본연구에앞서남녀간, 근원심골흡수의차이, 길이측정에이용되는프로그램내의오차에따른유의차가 Table 1. Number of implants in each jaws according to implant system 2) 임플란트-치조골접합부에서치조골가저부판독및기준점의설정 디지탈이미지에서, 임플란트-치조골경계부의흡수된치조골양상중최하방기저부의이미지를해당 Fig. 1. Schematic drawing illustrating measurement of margianl bone change in Brånemark implant. 72

4 III. 연구성적 가. 보철물장착후골소실량 Fig. 2. Schematic drawing illustrating measurement of margianl bone change in IMZ implant. 이없음을확인하고이들변수의영향을배제하였다. 따라서임플란트종류, 상하악을구분지어통계처리하여이들의영향을평가하고자하였다. 모든측정값은각각 6회씩측정하고각임플란트근, 원심면의평균값을구하고, 후최대값과최소값을버린후통계처리하여관찰자내유의차가없도록노력하였다. Wilcoxon Signed Rank test를이용하여각시기별측정값의유의차를검사하였고, 임플란트종류간의유의성검증에는 Mann-Whitney test를이용하였다. 1. Brånemark 임플란트의보철물장착후골소실량보철물장착시를기준으로하여 12 개월후에는 mm, 24개월후에는 mm의골소실을보였으며보철물장착 12개월이후 1년간진행된골소실량은 0.002mm이었다.(p<0.05) 2. IMZ 임플란트의보철물장착후골소실량보철물장착시를기준으로하여 12개월후에는 mm, 24 개월후에는 mm의골소실은보였으며, 보철물장착 12개월이후 1년간진행된골소실량은 mm 이었다.(p<0.05) 보철물장착후전체임프란트의골소실량은 12 개월후 mm이고 24개월후에는 mm였으며, 보철물장착 12개월이후 1년간진행된골소실량은 mm이었다 (p<0.05)(table 2, Fig. 3). 나. 임플란트두종류간의골소실량비교 12개월후골소실량비교시 IMZ 임플란트가 Brånemark 임플란트에비해유의성있게적었으며보철물장착 12개월이후 1년간진행된골소실량은 Brånemark 임플란트가적었다.(p <0.05) 다. 상하악간의골소실량비교상악에시술한임플란트수가적어통계학적으로비교할수가없었다. Table 2. Marginal bone level change around loaded fixtures. 73

5 라. 임플란트주위의치조골흡수양상 임플란트치경부주위의골변화는전형적인쐐기모양을나타내며초기 1년간급격한골흡수를나타내나 1 년이후에는 Brånemark 임플란트인경우임플란트첫번째나사부위에서안정됨을볼수있었고 IMZ 임플란트에서는연마된치경부하방 TPS(Titanium Plasma Spray) 된부위에서안정됨을알수있었다 ( 사진 1, 2, 3, 4, 5, 6). 그러나보철물의기계적결함 ( 나사의풀림, 휘어짐, 파절, resin 내부가동성기구의파열등 ) 이발생한임플란트의경우에는수평골흡수가동반된수직골흡수양상을볼수있었다.(Fig. 6, 7) 몇몇경우에는치조골소실이안정된후임플란트주변골의방사선불투과성이증가된양상도관찰할수있었다. Fig. 3. Marginal bone changes of loaded implants throughout the 2-year observation period for the two types of implants and total implants. IV. 고찰 우리나라부분무치악환자에서보철물장착후골유착성임프란트주위의치조골에미치는영향을평가하기위하여 Brånemark 임프란트와 IMZ임프란트에보철물장착시를기준으로하여 12개월, 24 개월후정기적으로촬영된구내방사선사진을컴퓨터를이용한방법으로골변화량을측정하였다. Hollender등 (27) 은방 사선검사시실제변연골높이와방사선사진상에서얻은값의차이가 0.3 mm를넘지않게하여야하며이를위해방새선수평조사각도를 9 이내에서유지하여동일한상을얻어야한다고하였다. 그러나동일한상을얻지못한경우에도제시하기도하였다. 본연구에서는변연골측정시 digital image 자체를프로그램상에서측정하고자하는부위의 pixel( 이미지의최소단위 ) 을측정함으로서다른연구에서발생하는측정자내오차를제거하여이를보관하였다. 방사선사진을표준화하기위하여 panoramic radiography 를이용하기도하는데 Molander등 46) 의연구에서와같이 ±1 mm 이상의차이를보이며변연골소실등의미세한변화인경우측정자의판독능력이저하된다는통계학적연구에따라본연구에서는구내방사선사진만을이용하였다. Sewerin (64, 65) 은Brånemark 임플란트과 IMZ 임플란트의구조가방사선사진촬영시에밀도와모양에미치는영향을분석하고그장단점을논의하면서나선구조 (implant thread) 를이용한판독의유용성에대하여논하였다. 그래서기존의연구에서는주로임플란트의전체길이를비례기준으로삼았으나하부의수직적으로형성된절단부와하단부구멍에의한이미지의변형을제외시키기위하여 Brånemark 임플란트는임프란트 shoulder를기준으로하였고, IMZ 임플란트에서는연마된치경부의임플란트직경을기준으로하여비례계산하는 program을이용하였다. Brånemark 임플란트를중심으로하여어러가지임플란트에대한비교연구방법 (15) 으로치조골상실에대한많은연구가진행되었다. Adell (1, 2, 3) 등, Henry등 (25), Jemt등 (34), Lekhlolm 등 (30), Quirynen등 (54), Steenberghe등 (60) Brånemark system의연구에서는초기 1년간 mm의급격한골소실을보인후안정되어향후 1년간골흡수는 mm의범위에서 15 년간성공적인보철물의안정성 (7) 을보인다고보고하였다. Adel (3), Quirynen등 (54, 55) 의보고에서기술통계값에서하악보다상악의골소실량이많지만통계학적유의차는없다고하였다. 이에비하여 IMZ system은상대적으로보고된바는적으나 3년간의연 74

6 구에서높은성공률과안정된골흡수양상을보고하고 Brånemark 임플란트와성공률을비교하면서부분무치악, 완전무치악, 단독치아의보철로나누어만족할만한결과를보고한연구 (40) 도있다. 이러한치조골소실은여자에서보다남자에서, 하악에서보다상악에서기술통계학상많은골소실량이보고되었지만 (34) 대부분통계학적유의차가없다고하였고 (3, 48, 53) 치태의골 (62, 70) 흡수에미치는영향에대하여의견이다양하다. 치태세균의분포를비교할때, 임플란트를식립한환자의부분무치악에서완전무치악에비해유의차있는결과 (52) 를나타낸반면부분무치악환자에서치아와임플란트사이의세균분포차이는유의차가없어골소실에영향을미치지않는다고보고하였다 (39). 그러나치아가같은구강내의티타늄임플란트의세균군집을위한공급자로서의역할을한다는데에는의견의일치를나타내어이는자연치아에서기인한치태세균이임플란트주위염을유발할가능성이있음을시사한다 (20). 임플란트형태의설계에따른골소실에대하여도 self-tapping fixture, standard fixture, comical fixture 순으로골흡수가증가되지만 (53, 66) 이러한설계와무관하게임플란트주위의과다한골소실은비정상적인기능에의한과부하로보는견해도있다 (37). 또한교합면재료의영향 47) 에대하여레진이충격흡수역할을한다고알려져있지만 (29, 67) 생체외, 생체내실험에서통계학적유의차는없다고하였다. 그러나순간적으로강한힘이작용될경우에는 resin이이러한충돌력 (impact force) 완화에효과적이라고하였다 (18). 본연구에서는 Brånemark 임플란트의경우보철욜장착후초기 12개월에는 1.831mm, 24 개월후관찰한결과 mm의골소실을보이며쐐기모양의전형적인골소실양상을나타내었다. IMZ 임플란트에서는초기보철물장착시를기준으로하여 12개월후에는 mm, 24개월후에는 mm의골소실은보였다. 보철물장착후초기 12개월동안 IMZ 임플란트보다 Brånemark임플란트에서골소실이많은이유는임플란트의구조적특성상수술시 Brånemark 임플란트식립시 countersinking시에가해지는외상과이후임플란트식립시조이는과정에서발생되는압력으로 인한골소실로추정된다. 또한보철물장착을기준으로 12개월이지난이후에진행되는골소실에서 Brånemark 임플란트가 IMZ 임플란트에비해적은이유는나선형임플란트의나선구조가골소실의진행을막는역할을할것으로추측된다. 각각의임플란트측정값을살펴보면골흡수량이반대로나타나골의증가를나타내는경우를볼수있는데이는 Adell (3), Quirynen등 (53) 의연구에서처럼주로상악의최후방지대치에서나타나 Adell등은이를 corticalization 에의한방사선불투과성의증가에기인한것 (50) 으로, 그원인이실제골체적의증가인지무기질성분의증가인지는알려져있지않다 (24). IMZ 임플란트생산자는내부 가동성기구가교합압을흡수, 분산시키는장점 (29, 44, 58) 이있고 Setz등 (63) 은감지되지않는미세한기계적결함을보상한다고하였다. 그러나사용한대부분의경우에사전부하 (preloading) 를부여해줄수없었기때문에반복적인나사의풀림, 휘어짐, 파절, 내부가동성기구의파열등지속적인보철물의기계적결함이나타나고이에따라급격한변연골소실이발생됨을관찰하였다. 그러나초기부터내부가동성기구를대신하여티타늄 IMC(Titanium IntraMobile Connenctor) 를장착한경우는 Brånemark 임플란트와유사한골흡수양상을보여안정된보철물상태를보여주었다. 이러한보철물의기계적결함에의한골흡수는 Quirynen (54) 등이보고한대로상대적으로 IMZ가높은임플란트표면거칠기를가져티타늄의높은표면에너지와함께치태침착에많은영향을미치는까닭도포함시켜고려해야한다. 이렇게방사선사진상초기골흡수가과다하게진행될경우이는보철물의기계적결함의전주곡이된다는이전의연구 (59) 와동일한결과를얻었다. 두가지종류의임플란트에서초기골소실은연마된치경부하방까지진행되는데 (59, 75, 76) 이는 Wolff (74) 의 stress concentration 개념으로설명되고이후여러의견이있어왔지만 (19) 골의재형성에응력이일정부분영향을미친다는데공통점을가지고있다. Haraldson (24) 에따르면치조골상실은수술시발생하는외상으로설명된다. 골막절개로인해혈류가차단 75

7 되고치조골변연부가절단되고, 임플란트식립시조이는과정에서발생된변연부응력이치밀골에집중되어연한해면골에영향을미치지못하여변연골부위에 Zone of Anemia 가형성되어초기변연골소실이일어나게된다. 본연구에서는보철물을연결하여저작기능이발휘된시점을기준으로변연골소실량을측정하였으므로주로저작압에의한골소실결과라고생각되며 Albreksson과 Zarb의연구에서임플란트식립후 1년간 2mm의골소실과 1년후연간 0.2mm 이내로안정되어야한다는것과비교하여유사한결과를나타내었다. 다소골소실량이많은경우도있어평균골소실량에대한표준편차가큰이유는우리나라환자의상악골과하악골자체의질과양의차이및섭취음식의차이, 저작습관의차이에의한것이라사료된다. 골조직은적절한시기가되면임플란트를통해전달된힘에대한반응으로골구조의변화및석회화작용 (mineralization) 을진행하게된다. 이는수술후진행되는부하와관련된골개조과정으로느린속도 (5) 로진행되며평형상태에도달할때까지최소 1년에서수년까지지속된다고한다. (36) 이렇게골흡수의증거를응력의측면에서볼때임플란트의설계를고려하지않을수없다. Brunsky (14) 는 IMZ 임프란트와같은원주형에서는전단응력이작용하고, 작용하고, Brånemark등의나사형에서는압축응력, 인장응력이주로작용한다고하였고 Clelland (16) 등은형태에관계없이치경부에응력집중이나타난다고하였다. 그러나나사형임플란트에서응력에의한골소실이첫번째나사에서안정되는것과같이원주형임플란트에서연마된치경부하방에서골소실이안정되는것을설명해주지는못하였다. 섬유성식이섭취가상대적으로많은동양인에게서 IMZ임플란트에서보철물의기계적결함의원인을이러한다양한응력및강도에관한측면에서조사해보는것도의의가있으리라사료된다. 본연 (1-3, 25, 34, 38, 구에있어서앞선골소실량은조사한연구 54, 69) 와차이를보이는이유를다음과같이생각해볼수있다. 첫째, 2차원적인골소실양상에서협설측의충첩된이미지에서다른연구에서와는달리최하방에위치한점을기준으로삼아측정한것이특히많은초 기골소실양상을보였다고여겨진다. 둘째, 디지탈이미지화시켜크고확대된화면상에서기준점을설정함으로서방사선판독에서간과되는미세한국소적인골흡수양상을설정함으로써위와같은결과를가져올수있다고생각된다. 그러나이와같은방법을이용함으로써이후연구에서의재현성과지속성, 객관성을확보하는데의의를찾을수있다고할수있다. 셋째, 본연구에서변수로고려하지않은항목중각환자가섭취하는음식물의종류, 저작습관, 저작시양상등서양인과다른점도연구성적에영향을줄수있는요인으로생각된다. 본연구에서임플란트는보철물장착후초기 12개월동안치조골소실을보인후안정되는양상을보여우리나라환자에게서도중장기적인안정된보철술식으로이용될수있다고사료되며또한치조골소실에영향을줄수있는보철물의기계적결함에대한광범위한임상연구가필요하리라사료된다. V. 결론 연세대학교치과대학치과병원에내원한부분무치악환자에서 Brånemark 임플란트와 IMZ 임플란트에보철물을장착한시점을기준으로하여 12개월, 24 개월후의치조골변화를방사선사진을이용하여비교한결과다음과같았다. 1. 전체임플란트에서골소실량은보철물장착시점를기준으로하여 12개월후에는 mm, 24 개월후에는 mm이었다.(p<0.05) 2. Brånemark 임플란트는보철물장착시를기준으로하여 12개월후에는 mm, 24개월후에는 1.833mm이었다.(p<0.05) 3. IMZ 임플란트는보철물장착시를기준으로하여 12개월후에는 mm, 24개월에는 mm이었다.(p<0.05) 4. 임플란트두종류간의골소실량을보철물장착시를기준으로하여비교시, 12개월후의골소실 76

8 량은 IMZ 임플란트가 Brånemark 임플란트에비해적었으며, 보철물장착 12개월후 1년간진행된골소실량은 Brånemark 임플란트가적었다.(p>0.05) 5. IMZ 임플란트에서사용중반복적으로보철물의기계적결함이발생한경우수평골흡수를동반한수직골흡수가일어났다. 이상의결과로임플란트주위의치조골소실은보철물장착후 1년간진행되고그이후안정됨을보이므로, 보철물장착후 1년간은사용시주의가필요하다고사료된다. 참고문헌 1. Adell, R. : Clinical result of osseointegrated implants supporting fixed prosthesis in edentulous jaw, J, Prosthet. Dent.,50 : 251, Adell, R., et al. : A 15-year study of osseointegral.ed implants in the treatment of the edentulous jaw, Int J Oral Surg., 6 : 387, Adell, R., et al. : Marginal tissue reactions at the osseointegrated titanium fixtures. I. A threeyear longitudinal prospective study, Int. J, Oral Surg.,15 : 39-52, Albrektsson, T. : Frakturl kningsteorier, Astra- Syntex, 1982 : Albrektsson, T., Branewark, P.-I., Mansion, H- A. & Lindstr m J. : Osseointe-grated titinium implants. Requirements for ensuring a longlasting direct bone-to-implant anchorage in man. Acta Orthop. Scand., 1981 : 52 : Albrektsson T., Sennerby L. : State of the art in oral implants, J. Clin. Periodontology, 18(6) : , 1991 Jul. 7. Albrektsson,T., Zarb,G., Worthington, P., Eriksson, A. : The long-term efficacy of currently used dental implants. A review and proposed criteria for success. Int J Oral Maxillofac Imp, 1 : 11-25, Al-Sayyed A., Deporter DA., Pilliar RM., et al. : Predictable crestal bone remodelling around two porous-coated titanium alloy dental implant design ; a radiographic study in dogs, Clin.Oral Implants Research, 5(3) : , 1994 Sep. 9. Bergman, B. : Evaluation of the result of treatment with osseointegrated implants by the Swedish National Board and Health Welfare, J, Prosthet. Dent. 50 : , Brägger U., Pasquali L. : Color conversion of alveolar bone density changes in digital subtraction images, J. Clin. Periodontol, 16 : , Brägger U. et al. : Digital subtraction radiography for the assessment of change in peri-implant bone density, Int. J. Oral Maxillofac. Implants, 6 : , Brånemark, P-I., et al. : Ossointegrated implants in the treatment of the edentulous jaw. Experience from a 10-year period, Scand. J. Plast. Reconstruc. Surg. 16(Suppl.), Brånemark, P.-I., Breine, U., Adell, R., Hassen B.-O., Lindstr m, J., Ohlsson, A. : Intraosseous anchorage of dental prostheses I. Experimental studies, Scand. J. Plast Reconstr Surg, 3 : 81-93, John B. Brunsky : Biomechanics of oral implants : future research directions, J. Dent. Edu. 52 : , Carl E. Misch : Contemporary implant dentistry, St Louis, C.V.Mosby, Co pp Clelland N.L. et al. : Use of axiosymmetric finite element method to compare maxillary bone variables for loaded implant, J. Prosthodontics, 2 : , Davis, D., Rimrott, R. & Zarb,G. : Studies on frameworks for osseointegral.ed prostheses : 77

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13 논문사진부도설명 Fig. 4. Radiograph of the Brånemark implants supporting at 30-month examination after delivery of prosthesis in mandiblar left molar. The marginal bone surrounding the fixture showed wedge shape but, marginal bone loss stabilized first thread(arrow). Fig. 5. Radiograph of the IMZ implants supporting at 30-month examination after delivery of prosthesis in mandiblar right molar. The marginal bone surrounding the fixtyre showed horizontal bone loss pattern but, marginal bone stabilized below polished neck of the implants(arrow). Fig. 6. Radiograph of the IMZ implants supporting at 12-month examination after delivery of prosthesis in left mandiblar molar. This happened mechanical failure such as rupture of the IMC intramobile element, screw loosening, screw bending repeatedly. Radiograph showed vertical bone loss pattern with moderate horizontal bone loss. Fig. 7. Radiograph of the same patient in fig 6. At 24-month examination. IMC intramobile element and IMC titanium insert were changed with Titanium IMC due to mechanical failure. No other prosthetic problem occurred thereafter. Radiograph showed stabilized marginal bone level without advanced bone compared with 2-month examination. 82

14 사진부도 Fig. 4 Fig. 5 Fig. 6 Fig. 7 83

15 =Abstract = RADIOGRAPHIC EVALUATION OF BONE CHANGE AROUND OSSEOINTEGRATED IMPLANTS IN PARTIALLY EDENTULOUS JAWS WITH FIXED TISSUE-INTEGRATED PROSTH ESES Yang Soon-Bong, Han Dong-Hoo Department of prosthodontics, College of Dentistry, Yonsei University This paper reports marginal bone loss around osseointegrated implants after loading in partially edentulous patients in dental hospital, Yonsei University. Two types of implants(brånemarktm, IMZTM)were used. Through the digital measurement on periapical radiograph around 37 implants in human subjects, marginal bone loss was observed for 24 months after delivery of prostheses. The results were as follows ; 1. According to experimental periods marginal bone loss in total implants was mm at 12 months, mm at 24 months after delivery of prostheses(p<0.05). 2. Marginal bone loss in the Brånemark implants was mm at 12 months, mm at 24 months after delivery of prostheses(p<0.05). 3. Marginal bone loss in the IMZ implants was mm at 12 months, mm at 23 months after delivery of prostheses(p<0.05). 4. During the first year after loading, the IMZ implants showed less marginal bone loss than the Brånemark implants but, during the next the Brånemark implants showed less than the IMZ implants(p>0.05). These results indicate that marginal bone loss around osseointegrated implants occurs within the first 12 months after delivery of prostheses and stabilizes thereafter, so it is necessary to be careful of using dental implants for the first year after delivery of prostheses. Key Word : marginal bone loss, partially edentulous patients, osseointegrated implants, radiographic evaluation 84