- 대한치과보철학회지 Vol. 35 No. 4, 1997 - 보철물조건에따른 Periotest 수치의실험적평가 이화대학교의과대학치과학교실보철과 한중석 Ⅰ. 서론 임플랜트를이용한구강수복의전제조건으로매식된임플랜트의몸체와골사이에 osseointegration 이라는안정된조건이형성되어상부에서가해지는기능력이보철물을통하여하부의임프랜트몸체및주변골에전달될때, 그경계면에서유지될수있어야한다 (1). 골과임프랜트몸체부와의성공적인 ossointegration 을임상적으로평가하기위하여방사선검사, 타진반응, Sound test, 동요도검사등이이용되어져왔다. 이러한방법들은골과임플랜트사이에섬유성피막이어느정도이상존재할때는임상적으로확인될수있으나아주얇은피막 (200um 이하 ) 이형성된경우, 상기한방법으로는민감도가떨어지고주관적인판단에의해골유착상태를평가하므로가성골유착 (pseudo-osseointegration) 으로오해하기쉬우며이러한임플랜트몸체는보철물장착후기능력을받으면골흡수와동요도를동반한실패를유발한다. 성공적인골유착 (osseointegration) 을판단하기위해수동적인방법에의한주관적인동요도측정법의보완책으로치아동요도를객관적으로측정하기위해소개된 Periotest(Simens, Germany) 가재현성, 정량적인측정기준, 민감성, 쉬운조작법등의장점으로인하여임플랜트의동요도측정에임상적으로이용되 어져왔다 (2-14). 하지만단일몸체인치아와는달리임플랜트는여러구조물의복합체로구성되기때문에어느과정에서그동요도를측정하는가에따라그수치의정확도및재현성이의심된다. 또한임플랜트몸체자체의동요도측정은임상적으로어려움이많아그위에연결되는지대주나보철물을이용하여대부분측정되므로여러가지변수가작용할수있다. 따라서이러한변수에의한영향을최소화하기위한올바른사용법이권장된다 (11). 본실험은이러한여러변수중수복물질의종류및보철물고정방법과종류에따른 Periotest value(ptv) 를비교하여그유용도를검사하였다. Ⅱ. 연구재료및방법 1. 이장재료에따른시편제작 자가중합형투명레진 (Orthocryl;Dentalum, Germany) 을진공혼합하여 2psi의압력하에서 250 150 20mm3부피의레진블럭을온성제작후각기다른이장재료가 PTV에미치는영향을비교하기위해두께약 1mm의 porcelain(noritake, Japan), type Ⅲ gold (Jelenko, USA), pure titanium을블럭제작에사용된자가중합레진을이용하여부착시켰고, composite 793

2. 보철물의고정방법과종류에따른시편제작 Fig. 1. 모형위에고정한이장재료 (titanium, porcelain, composite resin, acrylic resin, gold alloy) resin(z 100; 3M, USA) 과 cold cure resin(lang, USA) 을크기 10 10 1mm의사각형홈에각각광중합및자가중합시켰다 (Fig. 1). 시편의 PTV값을측정하기위하여 Periotest handpiece를각시편에수직되게위치시키고각 15 회씩측정하여그수치를비교하였다. 보철물의종류와고정방법에따른 PTV의차이를비교하기위하여세개의 13mm Mark Ⅱ implant fixture(nobel Biocare, Sweden) 를레진블럭에매식되도록하였다. 단일치수복시보철물고정방법에따른 PTV차이를조사하기위하여나사고정 (UCLA gold cylinder;3i, USA) 및시멘트고정 (Cera-One system;nobel Biocare, Sweden) 도재전장주조관을제작하였고나사고정단일관은 32Ncm torque로조이고 CeraOne 지대주는 32Ncm torque로조인후에도재전장관을 Tempbond(Kerr;Romulus, USA) 로고정하고치경부 1/3을타진하여 PTV를비교하였고 (Fig. 2), 마지막으로최종보철물의 PTV신뢰도를조사하기위하여나사고정도재전장 bridge를 standard와 Estheti-Cone abutment위에각각제작하였다 (Fig. 3). 모든구성품은 torque controller 를이용하여적정 torque로조였고각측정시편은 15 회씩하방1/3 타점부위에수직이되게 Periotest를위 Fig. 2 1. UCLA type 의나사고정금속도재관 Fig. 2 2. CeraOne Abutment 를이용한시멘트고정금속도재관 794

Fig. 3 1. 모형상에 standard abutment 가연결된상태 (20Ncm 로조였음 ) Fig. 3 2. 모형상에 EsthetiCone abutment 가연결된상태 (20Ncm 로조였음 ) Fig. 4 1. 각 abutment 위에제작된나사고정금속도재브릿지및타점방향 Fig. 4 2. 45 도각도로타진한경우 치시키고 PTV를측정하였다. 타진각도에따른차이를비교하기위해 45도각도로고정성보철물의소구치하방 1/3 부위를타진하였다 (Fig. 4). 통계처리를위하여 SAS program을이용하였고각실험군의평균및표준편차를구하고각변수의영향을비교하기위해 Duncan s multiple range test를행하였다. Ⅲ. 연구결과 각실험군의 PTV 값의평균과표준편차는아래와같다 ( 표1-4, Fig. 5-8). 이장재료에따른 PTV의평균과표준편차는표1과같다. resin block 자체는대조군으로사용하였고보 통많이사용되는크라운의이장재료인도재, 금합금, 복합레진, 아크릴릭레진및타이타늄을사용하였다. 이장재료에따라 PTV수치는약간의차이를보이나 resin block 과아크릴릭레진사이에는차이가없었으며복합수지레진, titanium, 금합금 (type Ⅲ) 사이에유의한차이는없었고, 도재가가장낮은 PTV값을보였다 (P<0.05). 나사고정용및접착형단일도재전장관에따른 PTV값은표 2에있으며 fixture 자체와 32Ncm torque로조인 Cera-One 지대주사이의 PTV 값은차이가없었으며고정방법에관계없이최종보철물장착후 PTV 값은현저하게높았다 (P<0.05). 나사고정용 3 unit bridge를표준형 (standard) 지대주에고정하기전, 후및타점에따른 PTV값은표 3 795

표 1. PTVs of different veneering materials( 이장재료에따른 PTV 값 ) 표 2. PTVs of single restorations( 단일금관에서연결방법에따른 PTV 값 ) (cementation type or screw retained type) 표 3. PTVs of Screw retained fixed bridge on 3mm Standard Abutment (3 mm standard abutment 상에 screw 로고정한 bridge 의 PTV 값 ) 표 4. PTVs of screw retained fixed bridge on 3mm EsthetiCone Abutment (3 mm EsthetiCone abutment 상에 screw 로고정한 bridge 의 PTV 값 ) 에나타나있다. 보철물연결후 PTV값은연결전표준지대주의 PTV값과비교시현저하게증가하였고표준편차도증가하는추세를보였다. 또한구치부의보철물하방을 45도각도로타진시 PTV값의표준편차가가장높았다. 표4는같은길이의 EsthetiCone 지대주상에제작된 bridge의고정전후의 PTV값으로표준지대주의 경우와마찬가지로보철물위에서측정한 PTV가지대주의 PTV값보다훨씬높았으며표준편차도너무커서신뢰도가떨어진다. 서로다른지대주 ( 표준및 EsthetiCone) 상에서측정한 PTV값은통계적으로유의한차이는없었다. 796

Fig. 5. PTVs of different veneering materials Fig. 6. PTVs of single restorations (comentation type or screw retained type) Fig. 7. PTVs of screw retained fixed bridge on 3mm standard abutment Fig. 8. PTVs of screw retained fixed bridge on 43mm EsthetiCone Abutment Ⅳ. 총괄및고안 Periotest는측정물체에 1초에 4 회씩, 4초간총 16 회에걸쳐 8gm의동적인충격을일정속도로주어접촉시간과감속을계산하여피검체의동요도를측정하는기구이다 (11). 이기구는객관적으로동요도를정량화할수있어자연치및임플랜트의동요도측정에사용되어져왔다 (2-14). 자연치는치근과치관이한부분으로연결되어있고임플랜트는종류에따라다르나대부분몸체부위에지대주가연결되고다시그위에치관이나사로고정되거나시멘트로합착하게된다. 동요도의측정은임플랜트몸체자체를측정하는것이가장신뢰할수있는방법이나이는잘못매식되어몸체부가치은밖으로돌출되지않는이상현실적으로불가능하다. 따라서지대주를연결한후에나임상적으로동요도측정이가능하며, 지대주의종류, 조이는힘 에의해PTV가차이가날수있다 (11). 주로지대주는 Titanium으로제작되나금합금도있으며심미적인이유나장착철거로를맞추기위해그위에형태를부여하여 custom abutment를제작하여시멘트로고정되는단일관이나 bridge를제작하기도한다. 또한임상적으로제작된보철물상에서 Periotest를사용하는경우도흔하므로이에대한정보가필요하다. 측정재료에따른차이는 resin block과같은재질을사용한경우는 PTV 값이영향을받지않았으며 titanium, gold alloy, composite resin 사이의 PTV 값은차이가없었으나 porcelain은더낮은값을보였다. Periotest의측정방법은동적인충격을물체에가하여감속시의접촉시간을분석하여수치로표시하므로이때물체의탄성계수와표면경도등이수치에영향 797

표 5. 각재료의 Knoop hardness 값 표 6. 각재료의탄성계수 (Elastic Modulus) 을미칠수있다. 시편들의탄성계수를비교해보면시험군의모든재료는 acrylic resin 보다최소 10배에서 50 배가량높은것을볼수있으며표면경도도재료들사이에서많은차이를보인다 ( 표 5, 6). 본실험에서탄성계수와표면경도가높은재료들이낮은 PTV값을보인것으로보아재료의경도와 stiffness 가 PTV 값에영향을미칠수도있으리라생각된다. 단일치수복에이용되는보철물의디자인은지대주상에금속을추가하여 crown을제작하여한개의나사로임프랜트몸체 (fixture) 와연결하여제작하는방법과미리제작된지대주를연결하거나지대주위에 wax-up을하여 custom abutment를제작하고나사로연결한후그위에제작된 crown을시멘트로합착하는방법이있다. 표 2에서보는바와같이 CeraOne abutment를연결하고 32Ncm로조인경우하방 1/3 지점에서 PTV를측정한값이가장 fixture 자체의동요도와근접하였고보철물제작후의값은높게측정된다. 따라서단일임프랜트의동요도측정시 CeraOne abutment를연결한후측정하는것이정밀하게보여진다. 나사고정방법과시멘트에의한고정방법에의한 PTV 값은표본수가한개뿐이어서그차이를개관적으로비교하기는곤란하나 crown 합착후에일단접촉부위는고정나사뿐이므로 PTV가비슷하게측정되지않았나생각된다. 지대주종류에따른나사고정시 bridge 보철물의 PTV차이를비교한결과 ( 표 3, 4), 보철물장착전에 Standard와 EsthetiCone지대주종류에따른 PTV 값의차이는전의실험에서와마찬가지로없었으나보철물장착후에는전후방위치에따른차이는물론측정치자체의표준편차도커서 PTV값의신뢰도가떨어진다. 더욱이임상적으로구치부는측정막대를수직하게위치시키기어려우므로종종비스듬하게측정하기도한다. 이때는임플랜트몸체주변의골질및양에따라수치가변동될가능성도있고, 본실험에서와마찬가지로그측정치의오차가크고변수가많아신뢰성이떨어진다. 또한보철물표면재료에따라측정치가다를수있으며, 외관의형태가일정하지않고, 나사를조이는힘이 torque device를사용하지않는경우균일하지못한등변수가너무많으므로두개이상의임플랜트를이용하여보철물을제작하는경우, 보철물상에서 PTV를측정하는것은신뢰도가떨어진다. Ⅴ. 결론 측정재료에따른 PTV 값과보철물고정방법및최종보철물상에서의 PTV 값을비교하여다음의결론을얻었다. 798

1. Type Ⅲ gold, titanium, composite resin, grade Ⅱ pure titanium 사이에 PTV 값은차이가없었으나 acrylic resin, 도재는유의한차이를나타냈다 (p<0.05). 2. CeraOne abutment는임프랜트몸체와유사한 PTV를보였으며단일치보철물의 PTV 값은적정 torque로조인경우연결방법에의한차이는없었다. 3. Bridge형보철물의 PTV 값은지대주의종류에관계없이불안정하였다. 4. 보철물상에서측정한 PTV 값과표준편차는지대주상에서측정한값보다크고불안정하며차이가있었다 (p<0.05). 참고문헌 1. Albrektsson T, Albrektsson B. Osseointegration of bone implants : a review of an alternative mode of fixation. Acta Orthop Scan. 1987; 58(5) : 567 577. 2. Chavez H, Ortman LF et al. Assessment of oral implant mobility. J Prosthet Dent. 1993;70 : 421 426. 3. Schulte W : A new field of application of the Periotest method. The occlusal-periodontal load can now be measured quantitatively. Zhanarztl Mitt. 78 : 1 11, 1988. 4. Van Scotter DE, Wilson CJ. The Periotest method for determining implant success, J Oral Implantol. 1991;17 : 410 413. 5. Buser D, Weber H-P. Tissue integration of nonsubmerged implants. 1-year results of a prospective study with 100 ITI hollow-cylinder and hollow-screw implants. Clin Oral Impl Res 1990;1 : 33 40. 6. Salonen M, Oikarinen K, et al. Failures in the osseointegration of endosseous implants. Int J Oral Maxillofac Implants, 1993;8 : 92 97. 7. Olive J, Aparicio C. The PERIOTEST method as a measure of osseointegrated oral implant stability. Int J Oral Maxioolfac Implants. 1990;5 : 390 400. 8. Tricio J, Laohapand P, et al. Mechanical state assessment of the implant-bone contunuum. A better understanding of the PERIOTEST method. Int J Oral Maxillofac Implants. 1995;10 : 43 49. 9. Teerlinck J Quirynen M, et al. PERIOTEST : an objective clinical diagnosis of bone apposition toward implants. Int J Oral Maxillofac Implatns. 1991;6 : 55 61. 10. Schulte W, Lukas D. PERIOTEST to monitor osseointegration and to check the occlusion in oral implantology. J oral Implntol. 1993;19 : 23 32. 11. 조리라, 한중석. Periotest를이용한임프랜트동요도측정방법에대한연구. 대한치과의사협회지 1995;33 : 12 : 1 10. 12. Schulte W, d Hoedt B et al. Periotest for measuring periodontal characteristics- Correlation with periodontal bone loss. J Periodont Res 1992;27 : 184 190. 13. May KB, Lang BR. The Periotest method : tightening sequence of the retaining screws for fixed/remote implant supported prostheses(abstr). J Dent Res 1995;74 : 553. 14. Manz MC, Morris HF, Ochi S : An evaluation of the Perioest system. Part I. Examiner reliability and repeatability of readings. Implant Dent 1992;1 : 142 146. 15. Biomaterials Properties Database, The University of Michigan 1996. 799

=Abstract= IN VITRO EVALUATION OF PERIOTEST VALUES UNDER VARIOUS CONDITIONS OF PROSTHESES Jung-Suk Han Dept. of Prosthodontics, Ewha Womans University Periotest(Siemens, Germany) has been used to test mobility of the implants clinically, however the effects of target materials and connection methods on the PTVs(Periotest Values) have not been evaluated. Periotest has been regarded as a reliable and objective tool to test implant and natural teeth mobility clinically, however this instrument showed different PTVs under various test conditions. This in vitro study was designed to compare PTVs of different veneering materials and prosthodontic designs(single and bridge restorations). To compare the effects of veneering materials on PTVs, 1 mm thickness of five different testing materials(porcelain, type Ⅲ gold alloy, pure titanium, composite resin, acrylic resin) were placed on the resin block. Three full length of 13 mm Mark Ⅱ implant fixtures were embedded into autopolymerizing resin block to fabricate single and bridge restorations. To evaluate effects of the connection method in single restorations, PTVs of screw retained(ucla type) and cementation type(cera- One system) were compared. Finally, to test reliability of PTVs of the final restorations, screw retained three unit short span PFM bridges were fabricated on the standard and Estheti-Cone abutments. All testing components were tightened with torque controller and PTVs of all specimens were measured 15 times for statistical analysis with SAS program. Following conclusions were made within the limit of this in vitro study. 1. PTVs of type Ⅲ gold alloy, grade Ⅱ titanium, composite resin veneering materials showed no significant differences, however acrylic resin and porcelain showed significant differences(p<0.05). 2. Single tooth restorations showed consistent PTVs as long proper torque force was applied. 3. PTVs of bridge type prostheses was inconsistent regardless of abutment types. 4. PTVs fo the prostheses showed higher scores and standard deviations than those of abutments regardless types of connection(p<0.05). 800