대한치주과학회지 2008;38:529-534 Resonance Frequency Analysis(RFA) 를이용한임플란트종류간의초기안정성비교 오준호, 장문택 * 전북대학교치의학전문대학원치주과학교실 Comparison of initial implant stability measured by Resonance Frequency Analysis between different implant systems Jun-ho Oh, Moontaek Chang * Department of Periodontology, School of Dentistry, Chonbuk National University ABSTRACT Purpose: The objective of this study was to compare initial implant stability measured by RFA between different implant systems during the initial healing period. Material and Methods: Fifty-four patients (36 males/18 females) who had been treated at the Department of Periodontology, Chonbuk National University Dental Hospital during the period between January and November in 2007 were included in the study. The mean age of the subjects was 49 years old (18 to 77). A total of 104 implants (Type A: 3i Osseotite, Type B: Replace select, Type C: ITI implant) were placed following the manufacturer's standard surgical protocols. Implant stability quotient (ISQ) readings were obtained for each implant at the time of surgery, 2-, and 4-month postoperatively. Result: No implant was failed during the observation period. At the baseline, the difference between mean ISQ values of 3 implant systems was statistically significant (p<0.05). However, at 2-, and 4-month following implant surgery, no significant difference was observed between ISQ values of the implant systems. In the same implant, the ISQ values of Type B and C implants increased (p<0.05), but those of Type A implants decreased during the 2-month healing period. The mean ISQ values of Type B and C implants showed a increasing tendency, while those of Type A implants were stable for the 4-month follow-up period. Conclusion: Within limits of this study, it can be concluded that implant design and surface topography of implant might influence the ISQ value and changing pattern during the initial healing period. (J Korean Acad Periodontol 2008;38:529-534) KEY WORDS: Resonance Frequency Analysis; dental implant; implant stability; initial healing. 서론 성공적인임플란트의주위조직에서일어나는골유착 (osseointegration) 은연조직의게재없는골과임플란트표면의직접적인구조적, 기능적결합을의미한다 1). 골유착을얻기위해처음제안된술식은 4~6 개월치유기간후임플란트에부하를가하는것이었으나, 즉시부하 (immediate Correspondence: Dr. Moontaek Chang Department of Periodontology, School of Dentistry, Chonbuk National University, Gumam-dong, Dukjin-gu, Chonju, 634-18, Korea. E-mail: chang@chonbuk.ac.kr, Tel: 82-2-250-2116, Fax: 82-2-250-2259 * 이논문은 2007 년도전북대학교병원연구비지원으로수행됨. Received: Aug 13, 2008; Accepted: Sep 11, 2008 loading) 나초기부하 (early loading) 술식역시높은예견성이있음이보고되면서 2,3,4) 초기안정성에대한중요성이부각되었다. Adell 등 1,5) 은임플란트의초기안정성이골유착의필수요건이라고하였고, 골유착의효과적예견지표로제안되었다 6,7). 또한높은초기안정성은임플란트에서좀더예견성있는즉시부하를가능하게한다 3). 임플란트의초기안정성을평가하는다양한방법이제시되었다. 임플란트상부를두드려보는 tapping test 5) 와방사선검사 8) 는안전성을평가하기에는부정확한단점이있고, 조직학적분석 9), 제거토크분석 (removal torque analysis) 10) 은침습적인문제가있기에이러한방법들은장 529
오준호, 장문택 대한치주과학회지 2008 년 38 권 3 호 기간연구에적합하지못하다. 이런문제점을극복하기위해 Periotest 가고안되어임플란트의골유착을평가하기위해사용되었다 11). 그러나 Periotest 값은측정방향과위치에많은영향을받기에생역학적지표 (biomechanical parameter) 로사용되기에는정확성이의심스럽다 12,13). Meredith 14) 는동물실험에서임플란트에변환기 (transducer) 를연결하고 resonance frequency(rf) 를측정하여임플란트주변골을분석하는비침습적방법을제시하였다. Implant stability quotient(isq) 로표시되는 RFA 측정값은 0~100 까지값을가지며, 높은값은안정성이높음을의미한다 14,15). RFA 측정으로임플란트의초기안정성을보고한많은연구들 7,14,15,19,21-23,26,27,29,30) 이있으나, 이들연구들은대부분한가지종류의임플란트에서초기안정성을비교분석하였으며 7,15,19,22,23,29,30), 다른형태의임플란트종류간초기안정성을비교분석한연구 19) 는드물다. 본연구의목적은 RFA 를이용하여초기골유착기간중에다른종류의임플란트시스템사이의 ISQ 의비교및변화를알아보고자한다. 재료및방법 1. 연구대상 2007 년 1월부터 11월까지전북대학교치과병원치주과에서임플란트매식수술을받은환자를대상으로하였다. 연구에포함된환자는모두 54 명 ( 남성 : 36 명, 여성 : 18 명 ) 으로평균나이는 49 세 (18~77 세 ), 이들가운데흡연자는 18 명이었다. 표면처리가다른세종류의임플란트 - Type A (Osseotite, 3i-implant Innovations, West Palm Beach, Florida, USA), Type B(Replace Select Tapered, Nobel Biocare, Göteborg, Sweden), Type C(ITI, Institut Straumann AG, Basel, Switzerland)- 가매식되었다. Type A 임플란트는산부식처리가된 Osseotite TM 표면이고 Type B 임플란트는 electrochemical process 방법을이용하여티타늄표면에자연적인산화막을입힌 TiUnite TM 표면이며다른임플란트와달리 tapered design 을가진다. Type C 임플란트는 SLA(Sandblast Large grit Acid etch) 표면을가지고 2.8 mm shoulder 가존재하여지대주 (abutment) 와의연결이치조골상방에위치하게된다. 매식된총 104 개의임플란트가운데 Type A 임플란트는 36 개, Type B는 48 개, Type C는 20 개이었으며, 임플란트의길이는 10~15 mm, 직경은 3.5~6 mm로분포되었다. 임플란트는전치부에 19개 (18.3%), 소구치부에 14개 (13.5%), 대구치부에 71개 (68.2%), 그리고상악에 49개 (47.1%), 하악에 55 개 (52.9%) 식립되었다. 일회수술법 (one-stage) 으로식립된임플란트는 58 개 (55.8%), 이회수술법으로식립된임플란트는 46 개 (44.2%) 였고 Type C 임플란트는모두일회수술법으로식립되었다. 구강내소독후 2% Hcl lidocaine(1:100000 epinephrine 함유 )(Xylestesin-A, 3M ESPE, Seefeld, Germany) 으로수술부위를마취하고, 절개후판막을거상한다음각임플란트시스템제조사에서추천한방법으로식립하였다. 피질골이두꺼운 type I(Lekholm & Zarb classification, 1985) 에서는 bone tapping drill을사용하였다. 식립시주변에골결손부가존재한 35개 (33.7%) 임플란트주위에는자가골이나이종골 (Bio-Oss, Geistlich AG, Wollhusen, Switzerland), 또는이를혼합하여골증대술을실시하였다. 2명환자에식립된 7개임플란트는잔존골이부족하여상악동이식술후 6개월째식립하였다 ( 모두 Type B 임플란트 ). 전치부에단독즉시임플란트가식립된오직한명의환자를제외한나머지환자에서는발치후골이충분히치유된시기에식립되었다. 흡수성차폐막을사용하여골재생유도술을실시한 4명의환자에서차폐막이노출되는문제를제외하고연구기간중다른후유증은관찰되지않았다. 노출된차폐막부위는 chlorhexidine( 클로헥신, 대웅제약, 성남시, 대한민국 ) 을사용하여 4~6 주간치료후치유되었다. 2. 연구방법각임플란트에맞는 magnetic peg(smartpeg TM ) 를연결하고 Osstell TM Mentor(Integration Diagnostics AB, Göteborg, Sweden) 을이용하여협측에서 2회측정하였다. 일회법으로시술된임플란트는수술시, 2, 4개월후에 RFA 를측정하였고, 2회법으로시행된임플란트에서는수술시, 지대주연결시 ( 술후 4개월 ) 에측정하였다. 530
J Korean Acad Periodontol 2008;38(3) Resonance Frequency Analysis(RFA) 를이용한임플란트종류간의초기안정성비교 3. 통계분석수술시와 2개월째측정한임플란트시스템간의 ISQ 값비교는 Mann-Whitney U test, 동일임플란트에서측정된수술시, 그리고 2개월째 ISQ 값의비교는 paired t-test 를사용하였다. 결과 임플란트식립시 Type A 임플란트의평균 ISQ 값은 76.2( 범위 : 48.5~87.0), Type B의평균 ISQ 값은 72.7( 범위 : 45.0~84.0), Type C의평균 ISQ 값은 67.6( 범위 : 41.0~84.0) 으로나타났다. 세그룹의 ISQ 값은통계적으로유의한차이를보였다 (p<0.05, Fig. 1). 그러나임플란트식립후 2개월째측정한평균 ISQ 값은 Type A, B, C에서각각 76.8( 범위 : 55.5~86.0), 77.8( 범위 : 67.0~85.5), 76.4( 범위 : 64.0~82.5) 로통계적으로유의한차이를보이지않았다 (Fig. 2). 임플란트수술시와 2개월후모두측정된임플란트를대상 (Type A; 14개, Type B; 14개, Type C; 16 개 ) 으로한 ISQ 값변화를관찰하면 Type A에서는감소한반면, 나머지 Type B, C에서는증가하는경향을보였다 (Fig. 3). Type B와 Type C는 2개월관찰기간동안통계적으로유의한증가가관찰되나 (P<0.05), Type A에서의감소는통계적유의성이없었다. 4개월째 ISQ 값이조사된 36 개의임플란트 (Type A; 13개, Type B; 15개, Type C; 8개 ) 를포함하여수술시, 2, 4개월사이의 ISQ 값변화를각임플란트시스템별로관찰하였다 (Fig. 4). Type A 임플란트는관찰기간중거의변화가없었지만, Type B, C 임플란트는관찰기간중증가하는경향을보였다. 80.0 70.0 50.0 40.0 Type A Type B Type C implant type Figure 1. Baseline ISQ values of 3 implant types. 80.0 70.0 50.0 40.0 Type A Type B Type C implant type Figure 2. 2-month ISQ values of 3 implant types. 80.0 70.0 50.0 * * Baseline 2-month 84.0 78.0 72.0 66.0 Type A Type B Type C 40.0 Baseline 2-moth 4-moth Type A Type B Type C implant type Figure 3. Comparison of mean ISQ values between implant surgery and 2-month postoperatively in 3 implant types * Statistically significant increase compared to surgery(p<0.05) Figure 4. Change of mean ISQ values for 4-month after implant surgery in 3 implant types 531
오준호, 장문택 대한치주과학회지 2008 년 38 권 3 호 고찰 임플란트의즉시또는초기부하술식이예견성있는치료로보고되면서 3,4) 임플란트의초기안정성의중요성이부각되었다. 초기안정성을비침습적방법으로측정하기위하여 RFA 가개발되었다 14). 이번연구에서세임플란트시스템의수술시 ISQ 값은 Type C에서가장낮은수치가기록되었다. 이임플란트시스템은즉시또는초기부하술식에성공적으로많이사용되고있으며 16-18), 일반적으로보철치료전약 6주의치유기간을추천한다 16,23). 이번실험에서도 Type C 임플란트는골이식이필요치않은부위에모두일회수술법으로식립되었고, 대부분 3개월째보철물이장착되어 4개월째 RFA 값은측정하지못했다. Ersanli 등 19) 은세가지임플란트시스템의 RFA 비교에서본연구에포함된 Type C와동일한임플란트의초기평균 ISQ 값이다른임플란트시스템보다낮은값 ( 평균 ISQ: 상악 ; 55, 하악 ; 60) 을가짐을보고하였다. 이들의연구에서측정된 ISQ 값은이번연구에서사용한 Osstell TM Mentor (magnetic device) 의이전모델 Osstell(electronic device) 로측정되었다. 두장치의 ISQ 값을비교한연구에서 Mentor 로측정한값이 8~12 정도높은값을보였음 20) 을감안하면이번연구에서의평균 ISQ 67.6 과 Ersanli 등 19) 의측정값이유사함을알수있다. 이렇게낮은값을보이는이유는 Meredith 등 21) 이언급한치조골상부임플란트높이 (supracrestal implant height) 와 RFA 값의강한상관관계에서찾을수있다. 3 mm 의치조골상부임플란트 shoulder때문에낮은 ISQ 가측정되었으며만약이길이가보정된다면다른임플란트와유사한값을보였을것이다 22). 또다른이유로는일부임플란트 (20 개중 4개 ) 에서식립시약간의임플란트자체의골내회전 (rotation) 이존재하였기에낮은 ISQ 값을보였을수있다. 많은연구에서 2개월이내의초기 ISQ 값의변화에대해서조사되었다 19,20,23). Barewal 등 23) 은다양한골질에식립된 SLA(Sand blast large grit acid-etched) 표면처리된임플란트에서의 ISQ 값을술후 6주까지매주, 그리고 8주, 10주째측정하였다. ISQ 값은골질에상관없이 3주째가장낮은값을보였고, 4주이후부터는골질그룹간차이가없었으며, 6주이후부터는안정기 (plateau stage) 에이른다고 하였다. 이러한변화는초기골접촉 (primary bone contact) 에의한임플란트수술후초기의기계적유지가시간이지남에따라임플란트와주위골사이의교직골 (woven bone) 이층판골 (lamellar bone) 로대체되는이차적인고정과정이반영된것이라고하였다 23,24). 이는 Roberts 등 25) 의토끼실험에서골에야기된상처의치유과정에서초기 (0~6 주 ) 에가골 (callus) 이생기고, 6주째부터층판골이침착되는것과일치하는내용이다. 본연구에서수술시와 2개월후값이동시에측정된임플란트를대상으로관찰시 Type A를제외한임플란트에서 ISQ 값의증가경향이관찰되는것은이러한층판골침착에의한결과로생각될수있다. 반면초기평균 ISQ 값이높은 Type A에서는 ISQ 값이거의변화없이유지되고있었으며, 오히려통계학적으로유의하진않지만약간의감소가관찰되었다. 결과적으로 2 개월째에는임플란트시스템사이에서평균 ISQ 값의유의한차이가관찰되지않았다. 이는낮은초기 ISQ 값을보이는임플란트는시간이지나면서그값이증가하고, 높은초기 ISQ 값을보이는임플란트는시간에따라그값이감소하여결과적으로임플란트간 ISQ 값에차이가줄어드는 catch up effect 로설명될수있다 7,23,30). 수술시, 2, 4개월후각각의시기에조사된임플란트그룹간의 ISQ 평균변화값을비교하면 Type B, C 임플란트에서는그값이지속적으로증가하고, Type A 임플란트는거의변화가없음이관찰된다. 이러한시간에따른 ISQ 값의변화는임플란트의형태, 표면처리등에영향을받은것으로보인다. 이런차이는다른연구에서도관찰되는데 Oʼ Sullivan 등 26,27) 은동물실험과인체해부실험에서 tapered design 의임플란트에서높은 RFA 값이관찰됨을보고하였고, 거친표면 (rough surface) 을가진임플란트에서평활면 (machined surface) 을가진임플란트에비해높은골-임플란트접촉 (bone-implant contact) 을보임을증명하였다 28). Glauser 등 15) 은성공한임플란트와실패한임플란트의 RFA 값의변화를조사하였다. 81 개의 Brånemark 임플란트중 9개 (11.2%) 가보철수복후 1년내실패하였는데실패한임플란트는성공한임플란트와달리 1개월후현저히 RFA 값이저하하였으며, 이들결과에서 RFA 의임플란트실패예견성의효용성을언급했다. 반면 Huwiler 등 29) 은연구에포함된임플란트에서단지한개의임플란트가실패했고, 임플란트의동요가임상적으로탐지된후에 ISQ 값의갑작스러운저하가관찰되었기에 RFA 의예측능력에의문을가 532
J Korean Acad Periodontol 2008;38(3) Resonance Frequency Analysis(RFA) 를이용한임플란트종류간의초기안정성비교 졌으며, Nedir 등 30) 은 RFA 가임플란트동요도를재현성있게진단하지못함을보고했다. 이번연구에서관찰기간중실패한임플란트는없었으므로, RFA 가임플란트실패를예견하기위해사용될수있는효용성을파악할수는없었다. 따라서실패한임플란트를다수포함하는연구로 RFA 의진단적가치에대한평가가필요할것이다. RFA 를이용하여측정된임플란트형태와표면이다른세종류의임플란트의초기안정성을비교한본연구에서임플란트수술시에는임플란트종류간에 ISQ 값의유의한차이가존재하였지만, 술후 2, 4개월째에는통계적으로유의한차이가관찰되지않았다. 시간에따른 ISQ 값의변화는임플란트시스템별로다른형태의변화를보였다. 그러므로적절한임플란트부하시기를결정하기위하여 RFA 를사용할경우임플란트시스템별로정상적범위의 ISQ 값을설정할필요가있다. 그리고초기 ISQ 값이나변화값으로임플란트의성공여부를예측하는 RFA 의효용성에대한연구가필요할것이다. 참고문헌 1. Brånemark PI, Hanson BO, Adell R. osseointegrated implants in the treatment of the edentulous jaw. Experience from a 10-year period. Scand J Plast Reconst Surg 1977;11 (Suppl 16):1-32. 2. Albrektsson, T. & Isidor, F. Consensus report of session V. IN Lang, N-P. & Karring, T., des. Proceedings of the 1st European workshop on periodontology. London: Quintessence Publ. Co. 1994;365-369. 3. Szmucler-Moncler S, Piattelli A, Favero GA, Dubruille JH. Consideration preliminary to the application of early and immediate loading protocols in dental implantology. Clin Oral Implants Res 2000;11:12-25. 4. Degidi M, Piattelli A. Immediate functional and non functional loading of dental implants: a 2- to 60- month follow-up study of 646 titanium implants. J Periodontol 2003;74:225-241. 5. Adell, R., Lekholm, Ul, Rockler, B. & Brånemark, PI. A 15-year study of osseointegrated implants in the treatment of the edentulous jaw. International Journal of Oral Surgery 1981;10:387-416. 6. Meredith, N. Assessment of implant stability as a prognostic determinant. International Journal of Prosthodontics 1998;11:491-501. 7. Friberg, B., Sennerby, L., Lin den, B., Grondahl, K. & Lekholm, U. Stability measurements of one-stage Brånemark implants during healing in mandibles. A clinical resonance frequency analysis study. International Journal of Oral & Maxillofacial Surgery 1999a;28:266-272. 8. Sunden S, Grondahl K, Grondahl HG. Accuracy and precision in the radiographic diagnosis of clinical instability in Brånemark dental implants. Clin Oral Implants Res 1995;6: 220-226. 9. Albreksson, T.& Jacobsson, M. Bone-metal interface in osseointegration. Journal of Prosthetic Dentistry 1987;57: 597-607. 10. Carlsson, L., Rostlund, T., Albrektsson, B. & Albrektsson, T. Removal torques for polished and rough titanium implants. International journal of Oral and Maxillofacial Implants 1988;3:21-24. 11. Olivé, J. & Aparicio, C. Periotest method as a measure of osseointegrated oral implant stability. International Journal of Oral and Maxillofacial Implants 1990;5:390-400. 12. Caulier, H., Naert, I., Kalk, W. & Jansen, J.A The relationship of some histologic parameters, radiographic evaluations, and Periotest measurements of oral implants: an experimental animal study. International journal of oral and maxillofacial implants 1997;3:380-386. 13. Derhami, Kl, Wolfaardt, J.F., Faulkner, G. & Grace M. Assessment of the periotest device in baseline mobility measurements of craniofacial implants. International journal of oral and maxillofacial implants 1995;10:221-229. 14. Meredith N, Alleyne D, Cawley P. Quantitative determination of the stability of the implant-tissue interface using resonance frequency analysis. Clin Oral Implants Res 1996;7:261-267. 15. Glauser R, Sennerby L, Meredith N, et al. Resonance frequency analysis of implants subjected to immediate or early functional occlusal loading. Successful vs. failing implants. Clin Oral Implants Res 2004;15:428-434. 16. Cochran DL, Buser D, tenbruggenkate C, et al. The use of reduced healing times on ITI implants with a sandblasted and acid etched surface: Early results from clinical trials on ITI SLA implants. Clin Oral Implants Res 2002;13:144-153. 17. Buser D, Schenk R, Steinemann S, et al. Influence of surface characteristics on bone integration of titanium 533
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