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1 ORIGINAL ARTICLE 3D-CT를이용한골격성 III급개방교합자의악교정수술전, 후설골및상기도의변화 이윤섭 a ㆍ백형선 b ㆍ이기준 c ㆍ유형석 c 본연구는골격성 III 급개방교합자의악교정수술전, 후설골과상기도의변화를 3D-CT 를이용하여관찰하고이를정상교합자와비교하기위하여시행하였다. 전치부개방교합을동반한골격성 III 급부정교합으로진단되어악교정수술을받은환자중 12 명을선정후, 3D-CT 를통해설골과상기도의 3 차원입체영상을분석하여, 악교정수술전, 후의설골의위치변화및상기도의부피변화를살펴보고, 이의결과를정상교합자 10 명과비교하였다. 설골은골격성 III 급개방교합군에서악교정수술전에정상교합군의설골에비해전방에위치하고있었고악교정수술후설골은후, 상방으로변화하였으나유의성은관찰되지않았다. Hyoid plane 과 mandibular plane 이이루는각은악교정수술전의골격성 III 급개방교합군이정상교합군보다큰값을나타내었고, 악교정수술후에는그차이가더욱증가하였다. 골격성 III 급개방교합군의상기도부피는정상교합자보다작으며이는, 악교정수술후에더욱감소하였다. 3 차원영상분석결과, 골격성 III 급개방교합자의상기도는정상교합자에비해좁으며, 하악골후퇴술이후더욱감소하기때문에이는수술적개선의안정성에영향을줄수있음을알수있었다. ( 대치교정지 2009;39(2):72-82) 주요단어 : 3 차원전산화단층사진, 골격성 III 급개방교합, 설골, 상기도 서론 악골의골격적부조화를가진환자의교정치료는적절한심미성, 기능성을얻기위해교정치료와함께악교정수술을필요로하며, 악교정수술에있어서술후회귀현상은가장심각하고, 근본적인술후합병증이자주된관심사이다. Cho와 Rhee, 1 Seo 와 Min 2 은술후에발생하는회귀현상을보고했고, 현재까지도골격성회귀는악교정수술의가장주목할만한술후합병증의하나이다. 특히전치부개방교합을동반하는골격성 III급부정교합환자의치 a 전공의, 연세대학교치과대학교정학교실. b 교수, c 부교수, 연세대학교구강과학연구소, 치과대학교정학교실, 두개안 면기형연구소. 교신저자 : 유형석. 서울시서대문구신촌동 134 번지연세대학교치과대학교정학교실 ; , yumichael@yuhs.ac. 원고접수일 : 2008 년 9 월 10 일 / 원고최종수정일 : 2009 년 2 월 20 일 / 원고채택일 : 2009 년 2 월 23 일. DOI: /kjod 본논문은 2008 년연세대학교치과대학두개안면기형연구소학술연구비지원에의하여연구되었음. 료는치료후높은회귀성향으로인하여술후안정성의분석이매우중요하다. 골격성 III급부정교합환자의악교정수술은하악을후퇴시키기때문에상기도를포함한악안면부위의경조직과연조직에영향을끼치게되며, 3,4 구강의용적감소와혀의위치및상기도의변화를야기시키고, 5 이로인해혀의압력이증가하여치열과악골형태의회귀를야기시킬수있다. 6,7 혀는해부학적으로는하악골과설골에직접연결되어있으나조직학적으로는활동범위와방향이넓은탄력성근육조직으로되어있어명확한기준점을설정하기어렵고직접적인계측이용이하지않다. 8 혀의위치와설골은상관성이깊다는 Tallgren과 Solow 9 의연구를바탕으로, 본연구에서는혀의위치를대변할수있는기준점으로설골을선택하였다. 개방교합을동반한골격성 III급부정교합환자에서악교정수술전, 후설골및상기도의변화를비교, 분석한다수의연구는현재까지측모두부방사선사진을이용한이차원적인방법으로주로행해지고있으나좌우상의중첩이정확한평가를어렵게 72

2 Vol. 39, No. 2, Korean J Orthod 악교정수술전, 후설골및상기도의변화 하며좌, 우확대율의차이가나고중안면의기형을발견해내기가힘들다는 10 한계점이있으며특히치열과악골형태의회귀를야기할수있는혀와설골및상기도는악골구조물의중첩등으로인하여정확한평가가어렵고평면적인분석으로인하여오류의발생가능성도배제할수는없다. 최근사용방법및계측방법에있어활발히연구가진행되고있는 3 차원전산화단층사진 (3-dimensional computed tomography, 3D-CT) 의경우실측이가능하며, 11 두경부위치에제한이없고, 각각의신체부위를보다자세하게, 360 도각도에서관찰할수있는등악골의다양한부위를보다정확하게분석할수있는많은장점이있다. 이러한이유로 3 차원전산화단층사진은두개악안면기형환자의진단과치료계획, 수술적지표, 수술결과의평가와그추적연구에최근들어널리사용되고있다. 12,13 Kawamata 등 14 은 3D-CT 를이용하여하악골후퇴술이후설골및상기도의변화를관찰하였으나, 기준평면및좌표를설정하지않고설골의위치변화를계측하였고상기도의변화를단면상에서관찰하였다는한계점이있다. 이에본연구에서는골격성 III 급개방교합자의악교정수술전, 후 3D-CT 를이용하여 3 차원영상재구성을통해상기도의부피를계측하였으며, 기준좌표를설정하여설골의위치변화를 3 차원적으로평가하였다. 또한악교정수술전, 후의설골및상기도의상태를정상교합자와각각비교하여, 골격성 III 급부정교합자의특징을알아보고자하였다. 종적으로선정하였다. 연구대상인골격성 III 급개방교합군 (Class III openbite group) 은총 12 명으로남자 4 명 ( 평균 23.5 세 ), 여자 8 명 ( 평균 21.4 세 ) 이었고 19 세에서 26 세까지의연령분포를보였다. 이중 7 명은이부전진성형술 ( 평균 4.5 mm) 을함께시행한환자였다. 대조군인정상교합군 (normal group) 은정상교합자인성인으로, 남자 5 명 ( 평균 19.8 세 ), 여자 5 명 ( 평균 20.0 세 ) 을선정하였다. 이들은특이할만한전신병력과골격성부정교합이없는정상교합자로치열이비교적잘배열되어있으며, 이전에교정치료를받은경험이없는자로정하였다. 연구방법 골격성 III 급개방교합군의초진 (T1) 과악교정수술 1 년후 (T2), 정상교합군의 3D-CT (N) 에대하여입체영상을제작하였다. CT Hispeed Advantage (GE Medical System, Milwaukee, Wis, USA) 를사용하여, 연구방법 연구대상 연세대학교치과대학병원교정과에내원한, 성장이완료된부정교합환자중전치부개방교합을동반한골격성 III 급부정교합으로진단된환자로, 임상검사상전치부수직피개가 0.5 mm 이하인환자, 악교정수술을받은경력이없고특기할만한악관절질환이없으며외상이나증후군의기왕력이없는환자를선정기준으로하였다. 선정된환자중개방교합및 III 급골격관계개선을위해한외과의에의한양악수술 (Lefort I osteotomy + bilateral intraoral vertical ramus osteotomy) 을시행받고수술후 1 년경에 3 차원전산화단층사진을촬영한자를최 Fig 1. Procedure of 3D image reconstruction using V-works TM 4.0 (Cybermed, Seoul, Korea). 73

3 이윤섭, 백형선, 이기준, 유형석 대치교정지 39 권 2 호, 2009 년 환자의 FH plane (Frankfort 수평면 ) 이바닥에수직이되게하고정중선과촬영장치의장축을일치시켜각환자의두정부에서하악골또는설골의하연까지포함되도록나선형 CT 를촬영하였다. 촬영영상은 V-works TM 4.0 (Cybermed, Seoul, Korea) 프로그램의 SSD (shaded surface display) 기능을사용하여 3D model 로재구성하였다. 재구성된영상은소프트웨어의 MPR (multiple planar reformat) mode 상에서전체악골, 하악골, 설골의 3 개 SOD (selection of demand) 로분할 (segmetation) 하였다 (Fig 1). 3 차원적인계측을위해계측점을설정하고 (Fig 2), 기준좌표를설정한후 (Fig 3), 기준평면을설정하여계측을시행하였다 (Fig 4). 계측점의지정과기준평면및좌표의설정은 Park 등 10 의연구에서제안한방법을사용하였다. 설골계측 설골 body 의중심을지나는가장최전상방점인 H (hyoidale) point 의 X, Y, Z 좌표에서의 3 차원적인위치와 Hyoid plane 과 Horizontal plane 이이루는각도중작은값 (H-Hori angle) 과 Hyoid plane 과 Mandibular plane 이이루는각도중작은값 (H-Mn angle) 을악교정수술전 (T1), 후 (T2) 에대해각각계측하고정상교합군 (N) 도계측하였다. Hyoid plane 과 Mandibular plane 이이루는각계측치가 180 o 를넘어서는경우는 reverse inclination 으로정의하고음 ( ) 의수치를부여하였다 (Fig 4). 상기도의부피계측 측정할상기도의범위를구인두 (oropharynx) 에한정하였고구인두가연구개에서부터후두개 (epiglottis) 까지를포함하므로제 1 경추 (cervical vertebrae) 의최전하방점 (C1) 에서부터제 3 경추의최전하방점 (C3) 까지골격성 III 급개방교합군의악교정수술전 (T1), 후 (T2), 정상교합군 (N) 의상기도부피 (airvol) 를세제곱밀리미터 (mm 3 ) 단위로계측하였다 (Fig 5). 하악골후퇴량, 후비극상방이동량과상기도부 Fig 2. Nine landmarks used in this study. Na (Nasion), Most posterior point on the curvature between frontal bone and nasal bone in the midsagittal plane; P (prechiasmatic groove), vertical and transverse midpoint of prechiasmatic groove; Or (orbitale), lowest point on the infraorbital margin of each orbit; Po (porion, anatomical), highest midpoint on the roof of the external auditory meatus; B (B point), greatest concavity point on the anterior border of the symphysis; Me (menton), most inferior point on the symphysis of the mandible; Go2 (gonion2), midpoint of the posterior border of mandibular angle; H (hyoidale), most upper and superior point at the middle of the hyoid bone; Hs (hyoidale superioris), most upper and posterior point at the greater horn of hyoid bone. Fig 3. Coordinate axis used in this study. A positive coordinate value indicates the front, superior, and left side of the patient, and a negative value indicates the opposite. Na (Nasion), Most posterior point on the curvature between frontal bone and nasal bone in the midsagittal plane. 74

4 Vol. 39, No. 2, Korean J Orthod 악교정수술전, 후설골및상기도의변화 Fig 4. Measurements of Hyoid bone. The 3-dimensional position of hyoid bone was obtained by measuring the distances between H point and Coronal, Midsagittal, and Horizontal planes. The angle between hyoid plane and horizontal, mandibular planes was obtained for the angular measurement. If the angle between hyoid plane and mandibular plane was more than 180 o, a negative value was used and defined as reverse inclination. Five reference planes were used in this study. Horizontal plane, parallel to the FH plane, which was constructed on both sides of Po and left of Or, passing through Na; Midsagittal plane, perpendicular to the horizontal plane passing through Na and P; Coronal plane, at right angles to the horizontal and midsagittal plane passing through Na; Mandibular plane, constructed by Me and both sides of Go2; Hyoid plane, constructed by H and both sides of Hs. Fig 5. Measurements of Airway space, Mandibular setback, PNS impaction. 3-dimensional reconstruction of upper airway was limited between C1 and C3. Mandibular setback was obtained by measuring the difference in the distance between Coronal plane and B point at pre-, post-surgery. PNS impaction was obtained by measuring the difference in the distance between Horizontal plane and PNS point at pre-, post-surgery. C1, lowest midpoint on the 1st cervical vertebrae; C3, lowest midpoint on the 3rd cervical vertebrae; B (B point), greatest concavity point on the anterior border of the symphysis; PNS (posterior nasal spine), the process formed by uniting the projecting ends of the posterior borders of the palatal process of the palatal bone; sback, difference of mandibular set back at T 1 and T 2; pimpaction, difference of PNS. 피변화와의상관성을알아보고자하였다. B point 의 Coronal plane 과의거리를통해 Y 축상에서의좌표를측정하였고이좌표의악교정수술전, 후의차이를하악골후퇴량 (mandibular setback, sback) 으로정하였다. 상악골의위치변화는후비극 (posterior nasal spine) 의 Horizontal plane 과의거리를통해 Z 축상에서의좌표를측정하였고이좌표의악교정수술전, 후의차이를후비극상방이동량 (PNS impaction, pimpaction) 으로정하였다 (Fig 5). 통계분석 본연구에사용된모든 3 차원전산화단층사진의계측및분석은동일한조사자에의하여행하여졌으며, 조사자내오차를확인하기위하여표본내의계측점을무작위로선정하여 1 주일후다시계측하여 paired t-test 를시행하였고 Kolmogorov-Smirnov 검사법을이용하여계측치들이정규분포를나타냄을확인하였다. 계측된자료들을다음과같이통계처리하였다. 75

5 이윤섭, 백형선, 이기준, 유형석 대치교정지 39 권 2 호, 2009 년 Table 1. 3-dimensional measurements and comparison of H (Hyoidale) between Class III openbite group at T1 and T2 and normal group (N) T1 T1 vs N T2 T2 vs N N Mean SD Sig Mean SD Sig Mean SD H - x (mm) NS NS H - y (mm) NS H - z (mm) NS NS H-Hori angle ( o ) NS NS H-Mn angle ( o ) p < 0.05; p < 0.01; NS, not significant; Sig, significance; SD, standard deviation; H-Hori angle, angle of hyoid plane and horizontal plane; H-Mn angle, angle of hyoid plane and mandibular plane. 골격성 III 급개방교합군과정상교합군 Hyoidale 의 3 차원적좌표, Hyoid plane 과 Horizontal plane 이이루는각도와 Hyoid plane 과 Mandibular plane 이이루는각도, 상기도부피를계측하여 paired t-test 로악교정수술전, 후간의차이와 independent t-test 로악교정수술전, 후와정상교합군간의차이를검정하였다. 성별에따른골격성 III 급개방교합군과정상교합군간의상기도부피차이를 independent t-test 로검정하였다. 하악골후퇴량, 후비극상방이동량과악교정수술전, 후상기도부피차이와의상관관계를 Generalized Linear Model (adjusted with site) 을이용하여분석하였다. 연구성적 검사자내오차 본연구의계측치측정에관한신뢰도를평가하기위하여시기별로무작위로 5 개의표본씩을추출하여 1 주간격으로동일한방법으로한명의조사자가재측정을시행하였으며, paired t-test 결과유의한차이가없었다 (p > 0.05). H (Hyoidale) 의 3 차원적좌표와각도계측비교 설골은골격성 III 급개방교합군에서악교정수술전에정상교합군의설골에비해전방에위치하고있었다 (p < 0.05). Hyoid plane 과 mandibular plane 이이루는각은악교정수술전에정상교합군보다큰값을나타내었고 (p < 0.05), 악교정수술후에는그차이가더욱증가하였다 (p < 0.01). Reverse Table 2. Mean treatment changes of H (Hyoidale) and upper airway volume (airvol) in the Class III openbite group ΔT2-T1 Mean SD p Sig H - x (mm) NS H - y (mm) NS H - z (mm) NS H-Hori angle ( o ) NS H-Mn angle ( o ) NS airvol (mm 3 ) -2, , p < 0.001; NS, not significant; H-Hori angle, angle of hyoid plane and horizontal plane; H-Mn angle, angle of hyoid plane and mandibular plane. inclination 은골격성 III 급개방교합군에서는나타나지않았고정상교합군에서 10 명중 4 명이 reverse inclination 을보였다 (Table 1). 골격성 III 급개방교합군에서하악골후퇴술을동반한악교정수술에의해설골은 2.48 mm 좌측으로, 3.9 mm 후방으로, 3.84 mm 상방으로이동한양상을보였지만통계적으로유의한차이는보이지않았다 (Table 2). Hyoid plane 과 horizontal plane 이이루는각 (H- Hori angle) 은악교정수술후 0.34 o 감소하였고, mandibular plane 과이루는각 (H-Mn angle) 은 2.55 o 증가하였으나통계적으로유의한차이는보이지않았다 (Table 2). 76

6 Vol. 39, No. 2, Korean J Orthod 악교정수술전, 후설골및상기도의변화 상기도의부피비교 골격성 III 급개방교합군에서악교정수술후상기도의부피는통계적으로유의성있게감소하였고 (p < 0.001) (Table 2), 골격성 III 급개방교합군의상기도부피는악교정수술전, 후모두정상교합군에비해유의성있게작은수치를보였다 (p < 0.001) (Table 3). 정상교합군에속한남성과여성은골격성 III 급개방교합군에속한남성과여성보다큰상기도부피를보였다 (p < 0.05) (Table 4). 하악골후퇴량, 후비극상방이동량과상기도부피변화와의상관관계 하악골후퇴량, 후비극상방이동량은악교정수술전, 후의상기도부피차이와관계가없었다 (Table 5). 고찰 교정영역에서전치부개방교합의해소에대한요구는날로높아지고있으나, 악안면기형을동반한환자의경우악교정수술을치료계획에포함하여야하는경우가많고수술을동반하여치료한이후전치부개방교합이다시발생하는경우도종종있다. 이는수술시하악지의길이가증가하는등수술방 Table 3. Comparison of upper airway volume (airvol) between the Class III openbite group at T1 and T2 and normal group (N) T1 T1 vs N T2 T2 vs N N Mean SD Mean Sig. Mean SD Mean Sig. Mean SD airvol (mm 3 ) 8, , , , , , , , p < Sig, significance; SD, standard deviation. Table 4. Comparison of upper airway volume (airvol) in male and female between the Class III openbite group at T1 and normal group (N) T1 N T1 vs N Mean (mm 3 ) N Mean (mm 3 ) N p Significance Male 12, , Female 7, , p < Table 5. Correlation between mandibular setback, PNS impaction and upper airway volume change in the Class III openbite group at T1 and T2 ΔT2-T1 Correlation Mean SD β p Significance sback (mm) NS pimpaction (mm) NS sback & pimpaction NS β, Linear regression coefficiency; NS, not significant; sback, horizontal change of B point at T 1 and T 2; pimpaction, vertical change of PNS at T 1 and T 2. 77

7 이윤섭, 백형선, 이기준, 유형석 대치교정지 39 권 2 호, 2009 년 법상의문제가원인일수도있으나상악후방부를상방이동하여양악수술을시행한경우에도전치부의개방교합이회귀하는경우가보고되고있다. Wickwire 등 15 에의하면하악골의수술적재위치후에는혀의위치변화가일어난다고하였으며 Swanson 과 Murray 16 는하악골의외과적후방위치후에는구강내의혀의공간이감소함으로인하여기능적인 macroglossia 가발생한다고하였다. 악교정수술에의해하악을후방이동시키면, 혀와설골은기도유지에방해가되지않도록하방이동을하게된다. 악교정수술후근육형태가변화하지못해변화된치열궁에위치적, 기능적으로적응하지못하게되면이는악교정수술결과의재발을야기할수있다. 또한혀는설측과협측연조직의압력의조화가변하면치아위치를변화시킬수있는힘을나타낼수있다. 6 또한 Enacar 등 17 은폐쇄성무호흡증을보이는환자에있어서하악골후퇴수술후와관찰기간동안구인두부기도공간의감소를주의하여야한다고하였으며 Greco 등 4 은하악골후퇴수술이후하인두부가감소하며수술 2-6 년후에도술전과비교해유의한감소를보고하였다. 하악골후퇴수술시구강내에서가장영향을많이받는부위는혀이며이로인해설골과연구개가영향을받고이는기도공간, 특히구인두부의기도공간에영향을주게된다. 하악골후퇴술을포함한악교정수술전, 후혀와설골, 상기도의변화를분석하여이를하악골후퇴술의술후안정성과함께연구한다수의보고가있고이러한연구는인두의성장에관한누년적연구에서정모두부방사선사진보다측모두부방사선사진을통해아데노이드를더잘관찰할수있다고보고한 King 18 의연구를바탕으로일반적으로측모두부방사선사진을계측하여이루어져왔다. 하지만본연구에서는악교정수술후설골및상기도의변화를 3 차원적으로관찰하고자 3D-CT 를이용하였다. 이번연구에서악교정수술전설골의 H point 는정상교합군에비해전방, 하방에위치하고있었고수술후유지기동안에도정상교합군에비해전방위치하는양상은계속유지되고있었다. 이는 I, II 급부정교합자에비해 III 급부정교합자에서설골이더전방에위치한다는 Adamidis 와 Spyropoulos, 19 Song 등 20 의연구결과와일치하였다. 설골과혀는설골설근을통해연결되어있어서설골과혀의위치는밀접한관련이있다는 Chang, 21 Cho 와 Rhee 1 의연구로미루어볼때골격성 III 급개방교합군혀의 위치가수술전, 후모두정상교합군에비해전방에위치한다고유추할수있다. Chin 과 Shon 22 은술전의혀와설골의위치로술후재발을미리예측하는척도로삼기위하여상관관계를조사하였지만유의성은보이지않았다고하였다. 골격성 III 급개방교합군에서 H-Mn angle 은악교정수술전에정상교합군보다통계적으로유의한큰값을나타내었고, 악교정수술후에는그차이가더욱증가하였다. 이는 I, II 급부정교합환아에비해 III 급부정교합환아에서 FH 평면과설골의최전상방점간의거리가가까워설골의경사도는 III 급군에서더완만함을알수있다는 Song 등 20 의연구결과와는일치하였으나 III 급부정교합군이 I 급부정교합군에비해하악평면에대하여설골장축이 reverse inclination 을나타낸다는 Adamidis 와 Spyropoulos 19 의연구와는다른결과를보였다. H point 는악교정수술후환자의후방, 상방으로이동하였으나통계적으로유의성있는차이는보이지않았다. 설골이악교정수술이후후방으로위치한다는결과는하악골전돌의수술적교정이후설골의위치변화를연구한다른연구들의결과와일치하지만, 수술이후상방으로변위하는결과를나타내어설골이하악골후퇴술후후방, 하방으로변위되고혀도설골과같이후방, 하방으로변위된다는이전의연구 14,17,23,24 와는다른양상을보였다. 이는하악골후퇴수술이후설골의위치변화를언급한대부분연구들의결과와는배치되는부분으로, 개방교합자의경우정상교합자보다설골이하방에위치하게되어이를수술적으로개선했을경우상방으로재위치되는하악골과함께설골이상방으로재위치되었다고생각해볼수있다. 또한본연구에서사용한 3D-CT 촬영술식을앙와위 (supine position) 에서시행한것도하나의원인으로고려해볼수있다. 설골은주위골조직과직접적연결이없기에설골의위치는하악과머리의위치, 25 기도상태에따라변하게된다. 촬영시두부의위치에따라서설골의위치가변화될수있다는 Ferrario 등, 26 Stepovich 27 의연구가이를뒷받침한다. 이와같이여러선학들의연구에의하면설골의위치는촬영시의두부자세변화에의해영향을받을수있기떄문에, 향후설골에대한연구는촬영조건의표준화를바탕으로진행해야하겠다. 골격성 III 급개방교합군에서악교정수술후상기도의부피는통계적으로유의성있게감소하였고, 하악골후퇴수술이후상기도공간의감소가일어남을확인하였다. 이결과는하악골후퇴수술 78

8 Vol. 39, No. 2, Korean J Orthod 악교정수술전, 후설골및상기도의변화 후기도공간이감소된후시간이경과하여도감소한양상이지속되었다는 Enacar 등, 17 Greco 등 4 의연구결과와일치하였다. 반면 Athanasiou 등 23 은하악골후퇴술 1년후주위의골격과연조직의생리학적적응을통하여수술하기전수준으로기도공간이유지된다고하였고 Wenzel 등 28 은측모두부방사선사진상의기도공간이감소하였다고하여기도저항이반드시증가하지는않는다고하였다. 이처럼하악골후퇴수술이후상기도변화에관한연구는아직논란의여지가있는상태로, 지금까지의연구들은기도변화를측정하기위하여사용되는계측점이명확하지않기때문에결과에있어서도차이를보일것이라예상되는바, 본연구에서는 3차원영상을사용하는이점을최대한이용하여제1경추의최전하방점과제3경추의최전하방점으로계측점을명확하게하였고 2차원의평면계측이아닌 3 차원의부피계측을이용하여상기도의악교정수술로인한부피계측을하였고, 이는 3D-CT를이용하여악교정술후상기도의협착을단면상에서관찰한 Kawamata 등 14 의연구와도일치되는결과를보였다. 또한이부전진성형술은상기도를증가시키고, 이는두개안면기형으로인한상기도협착이나수면무호흡의증세를보이는환자에서기도의공간을확보하는치료법으로사용되기도하는데, 29,30 이번연구대상 12명중 7명은이부전진성형술을시행받은환자로이를고려한다면상기도부피의감소는더욱클것임을예측할수있다. 골격성 III급개방교합군의상기도부피는정상교합군과비교시악교정수술전, 후모두유의성있게작은수치를보였는데 (p < 0.001), 이는인두내의구조인아데노이드나편도등의림프조직의비대와같은다양한원인들에의해이차적으로비호흡폐쇄가일어나면지속적으로구호흡을야기하게되어개방성하악골자세, 혀의전하방위치, 머리의신장이일어난다는 Kerr, 31 Dunn 등, 32 O'Ryan 등 33 의연구와연관지어생각해볼때좁은상기도의상태가개방교합과연관이있음을유추해볼수있다. 연구대상의남녀비율이실험결과에미치는영향을확인하기위하여비록연구대상숫자가적으나, 남성 ( 정상교합군 5 명, 골격성 III급개방교합군 4명 ) 만을대상으로비교분석한결과정상교합군에속한남성이골격성 III급부정교합군에속한남성보다큰상기도부피를보임을확인하였고, 여성 ( 정상교합군 5명, 골격성 III급개방교합군 5명 ) 의비교분석에서도정상교합군이골격성 III급개방교합군보다큰상기도부 피를나타냄을확인하였다 (Table 4 참고 ). 좁은상기도는하악골후퇴술로더욱악화되기때문에이는골격성 III 급개방교합을수술적으로개선했을때의안정성을저해할수있는요소로작용할수있다. 거대설, 구강의저형성증의경우에혀를내미는자세를취함으로써인두기도의확보를한다는 Takagi 등 34 의연구는이를뒷받침한다. 하악골후퇴술시변화된설골상근의길이는설골의위치만을반영하며골격적인재발에는영향을주지않는다고하였으나, 35 변화된위치의설골은재위치되면서혀후방의기도공간의감소를가져오게되고, 36 좁아진상기도로인하여혀의압력이높아진상태가지속된다면장기적인술후안정성에영향을줄수있기때문에이에대한추가적인연구가필요하다고하겠다. 하악골후퇴량및후비극상방이동량과상기도부피변화는유의성있는상관관계를보이지않았고, 표로제시하지는않았으나하악골후퇴량과설골의이동량도유의성있는상관관계를나타내지않았다. 이는하악골후퇴술 6 개월후설골의이동량이하악골후퇴량과유의성있는상관관계를갖는다는 Eggensperger 등 35 의연구와는상이하였으나, 유의성있는상관관계가술후 12 년에는약해지고또한본연구의측정시점과는차이가있어, 이번연구와관련하여악교정수술후장기간의추적연구의필요성이또한제기되었다. 전치부개방교합을동반한골격성 III 급부정교합환자의수술적치료에있어서수술의계획과교정치료의계획시술후회귀현상을방지하는것이무엇보다중요하다. 이번연구의진행에있어서 12 명으로표본의수가적어이부성형술에의한상관성여부및남녀에따른구별을할수없었고, 악교정수술후개방교합의재발이일어난표본이없었으며, 악교정수술직후에촬영한 3D-CT 가없었고, 3 차원적방법으로분석시명확한기준평면을설정하기가어려웠다. 이러한이유로, 이번연구에있어서수치의분석과평가및결론의도출에있어한계성이있다고본다. 향후 3 차원적분석에있어명확한기준평면및계측치의설정과, 많은표본수를확보하고, 3D-CT 의촬영조건을표준화하여연구를추가로시행한다면골격성 III 급개방교합자의진단및수술적치료계획과안정성평가에있어서더욱정확한분석이가능하리라생각된다. 79

9 이윤섭, 백형선, 이기준, 유형석 대치교정지 39 권 2 호, 2009 년 결론 전치부개방교합을동반한골격성 III 급부정교합으로진단되어악교정수술을받은환자중 12 명을선정후, 3 차원전산화단층사진을이용하여골격적수치의계측및설골과상기도의 3 차원입체영상을획득하고분석하여, 악교정수술전, 후의설골의위치변화및상기도의부피변화를살펴보고, 정상교합자 10 명을정상교합군으로하여, 비교한결과다음과같은결론를얻었다. 1. 설골은골격성 III 급개방교합군에서악교정수술전에정상교합군의설골에비해전방에위치하고있었다 (p < 0.05). 2. 골격성 III 급개방교합군에서하악골후퇴술을동반한악교정수술에의해설골은좌측, 후방, 상방으로이동한양상을보였지만통계적으로수술전과유의한차이는보이지않았다. 3. 골격성 III 급개방교합군에서 Hyoid plane 과 Mandibular plane 이이루는각은악교정수술전에정상교합군보다큰값을나타내었고 (p < 0.05), 악교정수술후에는그차이가더욱증가하였다 (p < 0.01). 4. 골격성 III 급개방교합군에서악교정수술후상기도의부피는통계적으로유의성있게감소하였고 (p < 0.001), 골격성 III 급개방교합군의상기도부피는악교정수술전, 후모두정상교합군에비해작았다 (p < 0.001). 이상의결과를통하여골격성 III 급개방교합자의상기도는정상교합자에비해좁으며, 하악골후퇴술이후더욱감소하기때문에이는수술적개선의안정성에영향을줄수있음을알수있었다. 참고문헌 1. Cho IJ, Rhee BT. A cephalometric study on the position of the hyoid bone in cleft lip and palate individuals. Korean J Orthod 1990;20: Seo BM, Min BI. Skeletal relapse after sagittal split osteotomies for correction of mandibular prognathism. J Korean Oral Maxillofac Surg 1991;17: Katakura N, Umino M, Kubota Y. Morphologic airway changes after mandibular setback osteotomy for prognathism with and without cleft palate. Anesth Pain Control Dent 1993;2: Greco JM, Frohberg U, Van Sickels JE. Long-term airway space changes after mandibular setback using bilateral sagittal split osteotomy. Int J Oral Maxillofac Surg 1990;19: Paik UB, Lee HC. A study of change of tongue position, hyoid bone position, and upper airway following sagittal split ramus osteotomy in mandible prognathism patients. Inje Med J 1999;20: Moss ML, Salentijn L. The primary role of functional matrices in facial growth. Am J Orthod 1969;55: Chung HS, Lee KS. The effect of functional pressures of the tongue and lips on the incisor relationship. Korean J Orthod 1983;13: Cuozzo GS, Bowman DC. Hyoid positioning during deglutition following forced positioning of the tongue. Am J Orthod. 1975;68: Tallgren A, Solow B. Hyoid bone position, facial morphology and head posture in adults. Eur J Orthod 1987;9: Park SH, Yu HS, Kim KD, Lee KJ, Baik HS. A proposal for a new analysis of craniofacial morphology by 3-dimensional computed tomography. Am J Orthod Dentofacial Orthop 2006;129:600.e Cavalcanti MG, Vannier MW. Quantitative analysis of spiral computed tomography for craniofacial clinical applications. Dentomaxillofac Radiol 1998;27: Kim HJ, Park HS, Kwon OW. Evaluation of potency of panoramic radiography for estimating the position of maxillary impacted canines using 3D CT. Korean J Orthod 2008;38: Jeon YN, Lee KH, Hwang HS. Validity of midsagittal reference planes constructed in 3D CT images. Korean J Orthod 2007;37: Kawamata A, Fujishita M, Ariji Y, Ariji E. Three-dimensional computed tomographic evaluation of morphologic airway changes after mandibular setback osteotomy for prognathism. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2000; 89: Wickwire NA, White RP Jr, Proffit WR. The effect of mandibular osteotomy on tongue position. J Oral Surg 1972;30: Swanson LT, Murray JE. Partial glossectomy to stabilize occlusion following surgical correction of prognathism. Report of a case. Oral Surg Oral Med Oral Pathol 1969;27: Enacar A, Aksoy AU, Sençift Y, Haydar B, Aras K. Changes in hypopharyngeal airway space and in tongue and hyoid bone positions following the surgical correction of mandibular prognathism. Int J Adult Orthodon Orthognath Surg 1994;9: King EW. A roentgenographic study of pharyngeal growth. Angle Orthod 1952;22: Adamidis IP, Spyropoulos MN. Hyoid bone position and orientation in Class I and Class III malocclusions. Am J Orthod Dentofacial Orthop 1992;101: Song YJ, Kim HJ, Nam SH, Kim YJ. Hyoid bone position in Class I, II and III malocclusions. J Korean Acad Pediatr Dent 1999;26: Chang YI. A radiographic study of the hyoid bone position in malocclusion. Korean J Orthod 1987;17: Chin KS, Shon WS. The relationships between the postoperative stability and the changes in the tongue position, the 80

10 Vol. 39, No. 2, Korean J Orthod 악교정수술전, 후설골및상기도의변화 hyoid bone position and the upper airway size after orthognathic surgery in patients with mandibular prognathism. Korean J Orthod 1993;23: Athanasiou AE, Toutountzakis N, Mavreas D, Ritzau M, Wenzel A. Alterations of hyoid bone position and pharyngeal depth and their relationship after surgical correction of mandibular prognathism. Am J Orthod Dentofacial Orthop 1991; 100: Gu G, Gu G, Nagata J, Suto M, Anraku Y, Nakamura K, et al. Hyoid position, pharyngeal airway and head posture in relation to relapse after the mandibular setback in skeletal Class III. Clin Orthod Res 2000;3: Tallgren A, Solow B. Long-term changes in hyoid bone position and craniocervical posture in complete denture wearers. Acta Odontol Scand 1984;42: Ferrario VF, Sforza C, Germanò D, Dalloca LL, Miani A Jr. Head posture and cephalometric analyses: an integrated photographic/radiographic technique. Am J Orthod Dentofacial Orthop 1994;106: Stepovich ML. A cephalometric positional study of the hyoid bone. Am J Orthod 1965;51: Wenzel A, Williams S, Ritzau M. Changes in head posture and nasopharyngeal airway following surgical correction of mandibular prognathism. Eur J Orthod 1989;11: Santos Junior JF, Abrahão M, Gregório LC, Zonato AI, Gumieiro EH. Genioplasty for genioglossus muscle advancement in patients with obstructive sleep apnea-hypopnea syndrome and mandibular retrognathia. Braz J Otorhinolaryngol 2007;73: Heller JB, Gabbay JS, Kwan D, O'Hara CM, Garri JI, Urrego A, et al. Genioplasty distraction osteogenesis and hyoid advancement for correction of upper airway obstruction in patients with Treacher Collins and Nager syndromes. Plast Reconstr Surg 2006;117: Kerr WJ. The nasopharynx, face height, and overbite. Angle Orthod 1985;55: Dunn GF, Green LJ, Cunat JJ. Relationships between variation of mandibular morphology and variation of nasopharyngeal airway size in monozygotic twins. Angle Orthod 1973;43: O'Ryan FS, Gallagher DM, LaBanc JP, Epker BN. The relation between nasorespiratory function and dentofacial morphology: a review. Am J Orthod 1982;82: Takagi Y, Gamble JW, Proffit WR, Christiansen RL. Postural change of the hyoid bone following osteotomy of the mandible. Oral Surg Oral Med Oral Pathol 1967;23: Eggensperger N, Smolka W, Iizuka T. Long-term changes of hyoid bone position and pharyngeal airway size following mandibular setback by sagittal split ramus osteotomy. J Craniomaxillofac Surg 2005;33: Kawakami M, Yamamoto K, Fujimoto M, Ohgi K, Inoue M, Kirita T. Changes in tongue and hyoid positions, and posterior airway space following mandibular setback surgery. J Craniomaxillofac Surg 2005;33:

11 ORIGINAL ARTICLE The structural change in the hyoid bone and upper airway after orthognathic surgery for skeletal class III anterior open bite patients using 3-dimensional computed tomography Yoon-seob Lee, DDS, MSD, a Hyoung-seon Baik, DDS, MSD, PhD, b Kee-joon Lee, DDS, MSD, PhD, c Hyung-seog Yu, DDS, MSD, PhD c Objective: The purpose of this study was to investigate the structural changes of the hyoid bone and upper airway after orthognathic surgery for skeletal class III anterior open bite patients, and make comparisons with normal occlusion. Methods: Pre- and post-operative computed tomography (CT) examinations were performed on 12 skeletal class III anterior open bite patients who were treated with mandibular setback osteotomy. Using the V-works 4.0 TM program, 3-dimensional images of the total skull, mandible, hyoid bone, and upper airway were evaluated. Results: In the Class III openbite group, the hyoid bone were all positioned anteriorly, compared to the Normal group (p < 0.05). The angle between the hyoid plane and mandibular plane in the Class III openbite group before surgery was greater than in the Normal group (p < 0.05), and the difference increased after surgery (p < 0.01). In the Class III openbite group, the volume of the upper airway decreased after surgery (p < 0.001) and the volume of the upper airway was smaller than the Normal group before and after surgery (p < 0.001). Conclusions: The narrow upper airway space in skeletal Class III openbite patients decreased after mandibular setback osteotomy. This may affect the post-surgical stability. (Korean J Orthod 2009;39(2):72-82) Key words: Three-dimensional computed tomography (3D CT), Skeletal class III openbite, Hyoid bone, Upper airway a Resident, Department of Orthodontics, College of Dentistry, Yonsei University. b Professor, c Associate Professor, Department of Orthodontics, College of Dentistry, Oral Science Research Center, The Institute of Cranio-facial Deformity, Yonsei University. Corresponding author: Hyung-Seog Yu. Department of Orthodontics, College of Dentistry, Yonsei University, 134, Shinchon-dong, Seodaemun-gu, Seoul , Korea ; , yumichael@yuhs.ac. Received September 10, 2008; Last Revision February 20, 2009; Accepted February 23,