Young-Mi Chung, Seong-Nyum Jeong 는파괴적인치주질환이다. 또한치태침착수준과일치하지않는치주염진행과심도를갖는다 [2]. 급진성치주염에서환자의감수성결정인자들에대한많은연구가있다. Hodge 등 [3] 은전반형급진성치주염에서흡연력보다유전적인자가더중요하다

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1 Original Article ORAL BIOLOGY RESEARCH 2013; 37(1): 한국인급진성치주염환자의치아상실및부착상실평가에관한연구 정영미ㆍ정성념 * 원광대학교치과대학대전치과병원치주과학교실 The evaluation of tooth loss and periodontal attachment loss in aggressive periodontitis patients Young-Mi Chung, Seong-Nyum Jeong* Department of Periodontology, Wonkwang University Daejeon Dental Hospital, School of Dentistry, Wonkwang University, Daejeon, Korea ABSTRACT Purpose: The aim of this study was to assess the prevalence of aggressive periodontitis as well as tooth loss and periodontal attachment loss in subjects who visited the Department of Periodontology of Wonkwang University Daejeon Dental Hospital. Materials and Methods: A total of 3,284 patients with periodontitis from January 2010 to June 2012 were included in this study. We investigated prevalence of periodontitis, age, gender, and clinical parameters (probing depth, gingival recession, tooth loss, periodontal attachment loss), and radiographic examination was performed at the baseline. Results: Sixty-six (2.01%) patients showed clinical features of aggressive periodontitis. Periodontal attachment loss of the maxillary first molar was 6.03 mm, which was the highest. The average number of missing teeth was 1.35 per subject. Tooth mortality was the highest at the maxillary first molar and at the mandibular second molar. Conclusion: Within the limitations of this study, periodontal breakdown as evaluated by attachment loss was the most severe at the first molars of aggressive periodontitis patients. It is important to recognize clinical features of aggressive periodontitis for proper diagnosis and determination of treatment timing. Further studies are needed to obtain more precise epidemiologic information, including the prevalence of aggressive periodontitis in Koreans, and investigate the potential roles of risk factors and contributory factors, such as root abnormality, occlusion, family aggregation, gene polymorphism, and Herpes virus infections. Key Words: Aggressive periodontitis, Periodental attachment loss, Tooth loss 서 론 Received Oct 31, 2012; Revised version received Dec 12, 2012 Accepted Feb 13, 2013 Corresponding author: Seong-Nyum Jeong Department of Periodontology, Wonkwang University Daejeon Dental Hospital, School of Dentistry, Wonkwang University, 77 Dunsan-ro, Seo-gu, Daejeon , Korea Tel: Fax: Seongnyum@wonkwang ac.kr 치주질환은치아표면에국소자극인자 (local irritants) 와치태 (dental plaque) 의형성으로유발되는만성염증성질환이다 [1]. 치태가주요기여인자로작용하나국소적인구강내요인, 전신질환, 임신과같은요인에도유발될수있는다인성질환이라할수있다. 그러나만성치주염과는다르게급진성치주염은젊은성인에서빠른부착소실과골파괴를특징으로하 14 This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

2 Young-Mi Chung, Seong-Nyum Jeong 는파괴적인치주질환이다. 또한치태침착수준과일치하지않는치주염진행과심도를갖는다 [2]. 급진성치주염에서환자의감수성결정인자들에대한많은연구가있다. Hodge 등 [3] 은전반형급진성치주염에서흡연력보다유전적인자가더중요하다고하였다. 급진성치주염에대한몇몇가족연구에서특정가족집단에서 40-50% 의유병률을보이는불균형을보고했다 [4,5]. African-American 과 Caucasian families에서는급진성치주염에대한유전적그리고 / 또는병인론적 (etiologic) 이종 (heterogeneity) 의가능성을제시했다 [6,7]. 최근발견에의하면 herpesvirus와급진성치주염간에관련이있다는근거를제공하기시작했다. Human cytomegalovirus와 Porphyromonas gingivalis의두감염체가질환의심도와유발에시너지작용으로영향을미쳐국소형급진성치주염과강력한관련있음을보고했다 [8]. 더구나 human cytomegalovirus, herpes simplex virus와 Epstein- Barr virus type-1은치주질환활성과통계적으로연관이있다고했다 [9,10]. 그외감수성결정인자들에는 single nucleotide polymorphism, polymorphonuclear neutrophils, 세균에대한항체, 흡연, 스트레스, 국소기여인자 ( 치근형태 ) 등이감수성과관련있다고알려져있다 [11]. 최근 systematic review 연구에서만성치주염과급진성치주염간의치은연하미생물총 (microbiota) 에차이가있다는증거가없다고결론지었다 [12]. 대신일반적으로받아들여지고있는것이치주염에대한질환의형태나감수성의차이를숙주인자에돌리고있다고했다 [13]. 숙주감수성을변화시키는요소는특히급진성치주염발병에서중요할수있다. 급진성치주염은질환의빠른진행과파괴성으로초기탐지를못한다면적절한치료시기를놓치기쉽다 [14]. 또한질환의재발과진행을예방하기위해서치주염의위험인자를인식하는것은중요하다. Matuliene 등 [15] 에의하면적극적인치주치료후 6 mm 이상의잔존치주낭이치주질환진행의위험인자라보고하였고, 5 mm 이상치주낭이 9부위이상있는경우위험인자라하였다. 급진성치주염의유병률은나라, 민족마다다양하게보고되고있고 [16], African-American populations에서는높은유병률이보고된다 [6]. 중국은 % 의유병률을보고했다 [17]. 성 (gender) 에따른발생차이도일관된결론은아직없다. Hørmand와 Frandsen [18] 은 12-32세의급진성치주염환자 156명에대한조사에서, 나이가증가할수록성에따른차이는감소한다고했다. 현재한국에서급진성치주염에대한유병률및임상특징에대한연구는충분하다고할수없다. 따라서본연구의목적은지난 2010년 1년에걸친급진성치주염환자에관한임상연구 [19] 에이어 2년 6개월동안원광대학교대전치 과병원치주과에내원한환자들을대상으로하여한국인급진 성치주염환자의유병률을예측하고, 치주부착상실과치아상 실을중심으로한치주조직의파괴정도를평가하는것이다. 연구대상 재료및방법 2010 년 1 월부터 2012 년 6 월까지원광대학교대전치과병원 치주과에내원한치주염환자 3,284 명을조사하였다. 급진성 치주염에대한진단은 American Academy of Periodontology International Classification 1999 를기준으로평가하였다. 추 가적으로 1) 40 세미만, 2) 치주질환가족력이있는경우를기 준에포함시켰다 (Table 1). 이연구는원광대학교치과대학연 구윤리위원회의승인을받아진행되었다 (IRB No. WKD IRB ). 임상검사 모든환자는초진시임상치주검사전에전신병력및치 과병력, 치주질환의가족력여부를기록하였다. 전신병력은 흡연여부, 고혈압, 당뇨유무와심장, 신장, 간질환등으로 인한수술병력을조사하였다. 임상치주검사에는치태지수 (Plaque Index, Löe & Silness 1967), 탐침치주낭깊이 (probing depth), 치은퇴축을검사하였다. 탐침치주낭측정은유리 치은변연에서치주낭기저부까지치주탐침 (PW; Hu Friedy Manufacturing Co., Chicago, IL, USA) 을사용하여설측및순 측에서각각한치아당총 6 부위를측정하였다. 치은퇴축은 백악 - 법랑질경계에서유리치은변연까지를동일기구를사 용하여측정하였다. 치주부착상실 (periodontal attachment Table 1. Diagnostic Criteria Based on the 1999 AAP Classification of Periodontal Diseases Criteria Localized aggressive periodontitis Rapid attachment and bone loss in otherwise healthy patients First molar-incisor presentation with no more than two other teeth affected At least two permanent teeth affected where at least 1 is a first molar LCAL 4 mm at the affected sites Generalized aggressive periodontitis Rapid attachment and bone loss in otherwise healthy patients Generalized interproximal attachment loss affecting at least three teeth other than first molars and incisors LCAL 4 mm at the affected sites AAP: American Academy of Periodontology, LCAL: lifetime cumulative attachment loss. 15

3 The evaluation of aggressive periodontitis in Korean loss) 은탐침치주낭깊이에치은퇴축을더한값으로하였 다. 모든검사는동일한검사자에의해수행되었고제 3 대구 치는제외시켰다. 치조골수준과치아상실및절망적인예후 (hopeless prognosis) 를가지는치아를평가하기위해전악치 근단방사선사진을평행촬영하였다 (PiView STAR software; Infinitt Co., Seoul, Korea). 절망적인예후에대한평가기준은 건강, 편의, 기능을유지하기에부적절한부착수준을의미한 다 [20]. 통계분석 SPSS 프로그램 ver (SPSS Inc., Chicago, IL, USA) 을사 용하여 chi-square test, one-way ANOVA 로비교분석하였다. 결 과 조사된치주염환자 3,284 명중에서급진성치주염으로진 Table 2. Frequency of Subjects by Gender Chronic periodontitis Aggressive periodontitis Total Female 1,016 (98.45) 16 (1.55)* 1,032 (100) Male 2,202 (97.78) 50 (2.22)* 2,252 (100) Total 3,218 (97.99) 66 (2.01) 3,284 (100) Values are presented as number (%). *No statistically significant difference by gender (p>0.05). Table 3. Smoking Status of Aggressive Periodontitis Patients Smoking Data Smoker 37 (56.1) Non-smoker 29 (43.9) Values are presented as number (%). Non-smoker means quit smoker and non-smoker. No statistically significant difference by smoking (p>0.05). 단받은환자는 66 명으로, 2.01% 의유병률을나타냈다. 평 균연령은 세 (±4.037) 였고, 남ㆍ여비율은남성 50 명 (2.44%), 여성 16 명 (1.30%) 으로남성이높은비율을나타냈으 나유의성은없었다 (p>0.05) (Table 2). 급진성환자 66 명중흡 연환자는 37 명 (56.1%) 으로나타났다 (Table 3). 전신병력은 60 명환자에서특이병력없이건강한상태였고림프선암, 심장 판막수술, 갑상선질환, 당뇨병력을가진사람이각한명, 고 혈압병력환자는 2 명으로나타났다. 치태지수는평균 1.7 을 나타냈다. 평균치주낭은상악제 1 대구치 5.16 mm, 하악제 1 대구치 4.80 mm 로평균치주낭이가장깊은치아는상악과하악모두 에서제 1 대구치였다 (p<0.05). 상악과하악비교시모든치아 에서상악의치주낭이깊었으나제 2 소구치에서만유의성이 있는차이를보였다 (p=0.029) (Table 4). 상악에서는제 1 대구치가 0.85 mm 로가장큰치은퇴축을보 였고 (p<0.05), 하악에서는중절치에서 0.41 mm 로가장컸으 나유의성은없었다 (p=0.08). 상악과하악비교시중절치를 제외한모든치아에서상악의치은퇴축이더컸으나통계적 유의성은제 1 대구치에서만있었다 (p<0.05) (Table 5). 부착상실은상악제 1 대구치 6.03 mm, 하악제 1 대구치 5.14 mm 로상악과하악모두제 1 대구치에서가장큰부착상실을 보였다 (p<0.05). 상악과하악비교시모든치아에서상악의 임상부착소실이더많았고, 제 1 대구치와제 2 소구치에서유 Table 5. Gingival Recession of Representative Teeth Central incisor 1st 2nd 1st molar Maxilla 0.29± ± ± ±1.12*, Mandible 0.41± ± ± ±0.67 Values are presented as mean±standard deviation (mm). *Statistically significant difference from maxilla group (p<0.05). Statistically significant difference between maxilla group and mandible group(p<0.05). Table 4. Probing Depth of Representative Teeth Central incisor 1st 2nd 1st molar Maxilla 3.96± ± ± ±2.26* Mandible 3.53± ± ± ±1.63 Values are presented as mean±standard deviation (mm). *Statistically significant difference from maxilla group (p<0.05). Statistically significant difference from mandible group (p<0.05). Statistically significant difference between maxilla group and mandible group (p<0.05). Table 6. Periodontal Attachment Loss of Representative Teeth Central incisor 1st 2nd 1st molar Maxilla 4.25± ± ± ±2.71*, Mandible 3.96± ± ± ±1.86, Values are presented as mean±standard deviation (mm). *Statistically significant difference from maxilla group (p<0.05). Statistically significant difference from mandible group (p<0.05). Statistically significant difference between maxilla group and mandible group (p<0.05). 16

4 Young-Mi Chung, Seong-Nyum Jeong Table 7. Tooth Mortality Rate by Tooth Type Missing teeth Hopeless Tooth mortality Maxilla Central incisor 10 (7.56) 3 13 (9.85)* Lateral incisor 6 (4.55) 0 6 (4.55)* Canine 4 (3.03) 1 5 (3.79)* 1st Premolar 9 (6.82) 9 18 (13.64)* 2nd Premolar 3 (2.27) (10.61)* 1st Molar 12 (9.09) (21.21)* 2nd Molar 10 (7.56) (19.67)* Total 54 (5.84) (11.90)* Mandible Central incisor 5 (3.79) 7 12 (9.09) Lateral incisor 2 (1.52) 5 7 (5.30) Canine 0 (0.00) 0 0 (0.00) 1st Premolar 3 (2.27) 3 6 (4.55) 2nd Premolar 6 (4.55) 4 10 (7.56) 1st Molar 8 (6.06) 6 14 (10.61) 2nd Molar 11 (8.33) 9 20 (15.15) Total 35 (3.79) (7.47) Values are presented as number (%, tooth mortality rate). *Statistically significant difference from maxilla group in tooth mortality (p<0.05). Statistically significant difference from mandible group in tooth mortality (p<0.05). 의성이있었다 ( 각각 p=0.005, p=0.028) (Table 6). 선천적상실, 교정발치, 우식또는외상에의한치아상실을 제외한치주질환으로인한치아상실을조사하였다. 첫내원 당시치아상실수는평균 1.35 개였으나절망적인예후로평가 된치아를상실치아로포함시켰을경우평균 2.71 개로두배 증가하였다. 이를치아상실률 (tooth mortality) 로분석하였을 경우가장높은상실률을보인치아는상악은제 1 대구치, 하악 은제 2 대구치였다. 가장낮은치아상실률을보인치아는상악 과하악모두견치로나타났다 (p<0.05) (Table 7). 고 찰 급진성치주염은대부분 0.2% 의낮은유병률을보고하나 African-American 집단에서는 2.5% 의현저히높은유병률이 보고된다 [6]. 사춘기집단에서급진성치주염의유병률에대 한지형학적다양성은 % 범위로추정된다고보고하 고있다 [6,7]. 인접국가인일본의경우 Kowashi [21] 는 세연령범위에서급진성치주염의유병률을 0.47% 로보고 했다. Albandar 와 Tinoco [22] 는민족, 사회 - 경제적수준이다 른집단에서의만성 / 급진성치주염에대한많은연구를통해, Hispanic-Black 민족집단또는낮은사회 - 경제적수준집단에 서높은유병률과심도를나타낸다고결론지었다. 본연구는치주염환자를대상으로하였기때문에 2.01% 의다소높은유병률을보였다고생각된다. 그러나한국에서급진성치주염의유병률에대한연구는많지않다. 이런상황에서치주염환자를대상으로한결과이긴하나일련의한국인급진성치주염환자의유병률에대한조사는의미가있겠다. 한편사춘기집단에서의급진성치주염연구를통한국소형급진성치주염의유병률과임상특성에대한연구가필요하다고생각된다. 급진성치주염환자의평균연령은 34.32세 (±4.037) 였다. 대부분의급진성치주염은 25세주변의젊은성인에서발견되고 [23,24], 급진성치주염진단에서나이는 30세미만으로하고있다 [2,25]. 그러나이번연구에서는나이기준을 40세미만으로하여높은평균연령이나온것으로생각된다. 이번논문은치주과에내원한환자를대상으로하였기때문에환자의자각증상유무와심도가내원에중요한요인이되었을것이고, 그로인해치주염개시 (onset) 의시점이명확하지못하다는한계점이있다. 따라서급진성치주염의조기진단이향후유병률을포함한역학적연구에서중요한요소라생각한다. 성별에따른치주질환위험도에관한증거는분명하게증명되지않고있다 [26-28]. 파괴적인치주질환에대한위험인자로성 (gender) 의상대적중요도는연구마다일치되지않고있다 [13,29,30]. 본연구에서는 3.13 : 1 비율로남자가우세하였으나, Baer [31], Hørmand 와 Frandsen [18] 은급진성치주염에서여성이우세함을보고했고 Albandar와 Rams [32] 는성별과급진성치주염에대한연관성을부정하였다. 따라서성에따른급진성을포함한치주질환의위험도는아직논쟁중으로향후한국인을대상으로광범위한역학적연구가필요할것으로생각된다. 치아상실에대한평가에서구치부의높은부착상실은높은치아상실로연결되는것같다. 첫내원당시치아상실수는평균 1.35개였고절망적인예후로평가된치아를상실치아로포함시켜치아상실률로분석하였을경우평균 2.71개로두배증가된결과가나왔다. Albandar 등 [14] 은 6년이넘는 multiracial controlled study에서최소한개이상의치아상실을보인급진성치주염환자가 46-50% 라고보고하였다. Matthews 등 [33] 의캐나다인치주염환자 335명연구에서는 20.6% 에서치아상실을보였다. 치아상실의요인으로치주질환 61.8%, 충치 24.8%, 그리고기타다른원인이 13.2% 라고설명하였고급진성치주염의경우치아상실의대부분이치주염때문이라고보고했다. Hirschfeld와 Wasserman [34] 은치주치료를받은 600명환자들을상대로한장기간조사에서평균 22년간관리하였을때환자당평균 1.8개의치아상실률을보고하였다. Kim 등 [35] 은 59명의환자를치주치료후평균 5.8년동안관 17

5 The evaluation of aggressive periodontitis in Korean 리하였을때환자당평균 1.42개의치아가상실되었다고하였다. 이번조사에서급진성치주염환자는 35세이하의나이에 3개가까운높은치아상실률을보였다. Machtei 등 [36] 은전반적으로복잡한구강상태로인해발치가더쉽게이루어질수있는것이급진성치주염에서높은치아상실률을설명할수있는가능한기전이라고했다. 이러한결과는급진성치주염의조기진단및치료법개발이필요하고중요함을의미한다. 구치부의높은치아상실의요인으로구강위생의어려움, 교합간섭등을추정해볼수있다 [19]. 그외에치근형태에대한영향도생각해볼수있다. 구치부치근의해부학적다양성은치태침착을호발시키는환경을제공하여국소적인치주문제를일으킬수있다고하였고 [37,38], 치근의형태, 길이및치근의수는구치부안정성과고정에상당한영향을미치고치아의예후를결정하는데중요한인자라고했다 [39]. 구치부치근융합은치근형태발생에서가장일반적인기형중에하나인데 [39,40], 발거한제1, 2대구치를이용한최근중국인의치근융합의완전 / 불완전한형태학적분석과유병률연구에서는치근융합과치주염간의상관관계가있음을보고하였다 [38]. 따라서향후급진성치주환자에서질환의기여인자로치근형태에대한연구도필요하다고생각된다. 본연구는지난급진성치주염에대한연구보다대략 5배정도더많은급진성치주염환자를대상으로분석을시행하였다는의미가있다. 가장많은부착상실을보인치아는제1대구치로앞선연구결과와일치하였고그외유병률, 평균나이, 성비에있어서도일치된연구결과를보였다. 더많은환자를대상으로한역학연구에서비슷한결과가나왔다는것은중요한점이다. 치주염은기본적으로다인성질환으로여겨지고있고급진성치주염의유병률은국가, 민족마다다른경향을보고하고있다. 따라서한국인의급진성치주염의유병률과임상형태의인지는빠른치주파괴를특징으로하는급진성치주염에서적절한진단과치료시기를놓치지않기위해서매우중요하다고할수있다. 이런점에서일련의급진성치주염에대한연구는의의가있고향후급진성치주염의기여인자로치근형태에대한연구도필요하다고하겠다. 감사의글 이논문은 2011년도원광대학교교비지원에의하여연구되었음. 참고문헌 1. Armitage GC: Classifying periodontal diseases--a long-standing dilemma. Periodontol :9-23, Tonetti MS, Mombelli A: Early-onset periodontitis. Ann Periodontol 4:39-52, Hodge PJ, Teague PW, Wright AF, Kinane DF: Clinical and genetic analysis of a large North European Caucasian family affected by early-onset periodontitis. J Dent Res 79: , Boughman JA, Astemborski JA, Suzuki JB: Phenotypic assessment of early onset periodontitis in sibships. J Clin Periodontol 19: , Marazita ML, Burmeister JA, Gunsolley JC, Koertge TE, Lake K, Schenkein HA: Evidence for autosomal dominant inheritance and race-specific heterogeneity in early-onset periodontitis. J Periodontol 65: , Albandar JM: Epidemiology and risk factors of periodontal diseases. Dent Clin North Am 49: , McLeod DE, Lainson PA, Spivey JD: The effectiveness of periodontal treatment as measured by tooth loss. J Am Dent Assoc 128: , Michalowicz BS, Ronderos M, Camara-Silva R, Contreras A, Slots J: Human herpesviruses and Porphyromonas gingivalis are associated with juvenile periodontitis. J Periodontol 71: , Kamma JJ, Contreras A, Slots J: Herpes viruses and periodontopathic bacteria in early-onset periodontitis. J Clin Periodontol 28: , Ling LJ, Ho CC, Wu CY, Chen YT, Hung SL: Association between human herpesviruses and the severity of periodontitis. J Periodontol 75: , Armitage GC, Cullinan MP, Seymour GJ: Comparative bio logy of chronic and aggressive periodontitis: introduction. Periodontology :7-11, Mombelli A, Casagni F, Madianos PN: Can presence or absence of periodontal pathogens distinguish between subjects with chronic and aggressive periodontitis? A systematic review. J Clin Periodontol 29(Suppl 3):10-21, Page RC, Beck JD: Risk assessment for periodontal diseases. Int Dent J 47:61-87, Albandar JM, Brown LJ, Löe H: Dental caries and tooth loss in adolescents with early-onset periodontitis. J Periodontol 67: , Matuliene G, Pjetursson BE, Salvi GE, Schmidlin K, Brägger U, Zwahlen M, Lang NP: Influence of residual pockets on progression of periodontitis and tooth loss: results after 11 years of maintenance. J Clin Periodontol 35: , Albandar JM, Brown LJ, Löe H: Clinical features of early-onset periodontitis. J Am Dent Assoc 128: , Meng H, Xu L, Li Q, Han J, Zhao Y: Determinants of host susceptibility in aggressive periodontitis. Periodontol : , Hørmand J, Frandsen A: Juvenile periodontitis. Localization of bone loss in relation to age, sex, and teeth. J Clin Periodontol 6: ,

6 Young-Mi Chung, Seong-Nyum Jeong 19. Cho CM, You HK, Jeong SN: The clinical assessment of aggressive periodontitis patients. J Periodontal Implant Sci 41: , Newman M, Takei H, Klokkevold P, Carranza F. Carranza's clinical periodontology. Philadelphia: Elsevier, p Kowashi Y: Prevalence of juvenile periodontitis among students at Nagasaki University. Adv Dent Res 2: , Albandar JM, Tinoco EM: Global epidemiology of periodontal diseases in children and young persons. Periodontol : , Ranney RR: Classification of periodontal diseases. Periodontol :13-25, Suzuki JB, Charon JA: Current classification of periodontal diseases. J Parodontol 8:31-51, Lindhe J, Lang NP, Karring T: Clinical periodontology and implant dentistry. Oxford: Blackwell, p Norderyd O, Hugoson A, Grusovin G: Risk of severe periodontal disease in a Swedish adult population. A longitudinal study. J Clin Periodontol 26: , Hermann P, Gera I, Borbély J, Fejérdy P, Madléna M: Periodontal health of an adult population in Hungary: findings of a national survey. J Clin Periodontol 36: , Van der Velden U, Abbas F, Armand S, Loos BG, Timmerman MF, Van der Weijden GA, Van Winkelhoff AJ, Winkel EG: Java project on periodontal diseases. The natural development of periodontitis: risk factors, risk predictors and risk determinants. J Clin Periodontol 33: , Burt B; Research, Science and Therapy Committee of the American Academy of Periodontology: Position paper: epidemiology of periodontal diseases. J Periodontol 76: , Genco RJ: Current view of risk factors for periodontal diseases. J Periodontol 67(10 Suppl): , Baer PN: The case for periodontosis as a clinical entity. J Periodontol 42: , Albandar JM, Rams TE: Risk factors for periodontitis in children and young persons. Periodontol : , Matthews DC, Smith CG, Hanscom SL: Tooth loss in periodontal patients. J Can Dent Assoc 67: , Hirschfeld L, Wasserman B: A long-term survey of tooth loss in 600 treated periodontal patients. J Periodontol 49: , Kim HS, Seok JJ, Kim HC, Lee SJ, Choi SH: Study on tooth mortality after periodontal therapy. J Korean Acad Periodontol 33: , Machtei EE, Hausmann E, Dunford R, Grossi S, Ho A, Davis G, Chandler J, Zambon J, Genco RJ: Longitudinal study of predictive factors for periodontal disease and tooth loss. J Clin Periodontol 26: , Hou GL, Tsai CC: Relationship between palato-radicular grooves and localized periodontitis. J Clin Periodontol 20: , Hou GL, Tsai CC: The morphology of root fusion in Chinese adults (I). Grades, types, location and distribution. J Clin Periodontol 21: , Hou GL, Tsai CC, Huang JS: Relationship between molar root fusion and localized periodontitis. J Periodontol 68: , Ross IF, Evanchik PA: Root fusion in molars: incidence and sex linkage. J Periodontol 52: ,

한국성인에서초기황반변성질환과 연관된위험요인연구

한국성인에서초기황반변성질환과 연관된위험요인연구 한국성인에서초기황반변성질환과 연관된위험요인연구 - - i - - i - - ii - - iii - - iv - χ - v - - vi - - 1 - - 2 - - 3 - - 4 - 그림 1. 연구대상자선정도표 - 5 - - 6 - - 7 - - 8 - 그림 2. 연구의틀 χ - 9 - - 10 - - 11 -