口腔解剖生理学：磨牙组

DepartmentofOralBiologyDMU

口腔解剖生理学Oralanatomyandphysiology磨牙组MolarsDepartmentofOralBiologyDMU一、位置和数量

PositionandnumberDepartmentofOralBiologyDMUDepartmentofOralBiologyDMU生长叶的构成66DepartmentofOralBiologyDMU二、功能FunctionsDepartmentofOralBiologyDMUBLMO上颌第一磨牙maxillaryfirstmolarDepartmentofOralBiologyDMU上颌第一磨牙(颊面)maxillaryfirstmolar(buccalsurface)近中M远中D上颌第一磨牙

颊面(BuccalS)：1呈梯形，牙合缘长于颈缘，近远中宽度大于牙合颈高度，近中缘长直，远中缘稍短突。牙合缘由近远中颊尖的近远中斜缘相连续组成（M形）2近中颊尖略宽大>远中颊尖;近中颊轴嵴略突显；两颊尖之间有颊沟通过，此沟与牙长轴（or颊轴嵴）平行，终止于冠中部，其终点形成点状凹陷，并分出两条小沟。外行高点：颊颈嵴—颈1/3DepartmentofOralBiologyDMUDepartmentofOralBiologyDMUmaxillaryfirstmolar(lingualsurface)近中M远中D舌面(LingualS):与颊面相近或稍小,近中舌尖>>远中舌尖,舌轴嵴不明显，远中舌沟,外形高点在中1/3。DepartmentofOralBiologyDMUCarabelli’scusp卡式尖少数近中舌尖的舌侧有第5尖，卡式尖（19%），小，短，无功能，尖顶未达到牙合面，内部无髓角，所以不是真正的牙尖，应称为卡式结节。DepartmentofOralBiologyDMUmaxillaryfirstmolar上颌第一磨牙(邻面)舌侧LB颊侧BL邻面(ProximalS)：四边形，颊舌径（厚度）>牙合颈径（高度），接触区：近中接触区在牙合偏颊侧；远中接触区在牙合中1/3P39舌侧LB颊侧DepartmentofOralBiologyDMUmaxillaryfirstmolar(occlusalsurface)上颌第一磨牙远中D近中MLB上颌第一磨牙

牙合面(OccusalS):1.斜方形颊牙合边缘嵴——近远中颊尖的4个牙尖嵴舌牙合边缘嵴，近远中边缘嵴颊舌径稍>近远中径；颊侧稍>=舌侧近舌牙合角，远颊牙合角为钝角，MBO,DLO角为锐角2.牙尖cusp：4个牙尖，

近中舌尖>近中颊尖>远中颊尖>远中舌尖

最大，功能尖最小颊尖高锐，舌尖低钝DepartmentofOralBiologyDMU3.三角嵴：斜嵴：牙合面远中颊尖三角嵴与近中舌尖三角嵴斜形相连，是上颌磨牙的重要解剖标志。4.窝fossa:斜嵴将牙合面分成近中窝，远中窝

中央窝，大，占2/3

小，占1/35.沟groove:k形发育沟颊沟——中央点隙伸向颊侧近中沟——中央点隙(最低点)伸向近中远中舌沟——一端至远中边缘嵴之内，一端经两舌尖之间到舌面4尖，3沟，2窝，1点隙，K形沟，DepartmentofOralBiologyDMUDepartmentofOralBiologyDMU斜

嵴obliqueridge——————————Wheeler'sdenalanatomy，physiologyandocclusionStanleyJ.Nelson2012Maxillaryfirstmolar(occlusalaspect)MBCR,Mesiobuccalcuspridge;CF,centralfossa(shadedarea);MTF:mesialtriangularfossa(shadedarea);MMR,mesialmarginalridge;MLCR,mesiolingualcuspridge;DF,distalfossa;DTF,distaltriangularfossa(shadedarea),DMR,distalmarginalridge;DBCR,distobuccalcuspridge;DLCR,distolingualcuspridge;OR,obliqueridgeDepartmentofOralBiologyDMUDepartmentofOralBiologyDMU两颊根：近中颊根长大>远中颊根短小；根的近远中面平，颊面宽于舌面舌根：三根中最粗大，近远中径大，颊舌径小，舌面有沟，两颊根之间相距较近，颊根与舌根之间分开较远根干——牙根未分叉的部分牙根rootoftoothDepartmentofOralBiologyDMU牙根rootoftoothDepartmentofOralBiologyDMUDepartmentofOralBiologyDMU6

7

8DepartmentofOralBiologyDMUBuccalsideOcclusalsideDistalsideFirstmolarSecondmolar上颌第一、二磨牙的区别整体：内收冠、根牙合面：斜方形

斜度>6牙冠颊面自近中向远中舌侧倾斜

斜嵴：不明显，有沟横过舌尖：远中舌尖<<近中舌尖甚至缺如极少有第5尖邻面：近远中接触区：牙合中1/3与6区别牙根：颊舌根间分叉度小，且向远中偏斜。少数颊根与舌根融合或颊根融合DepartmentofOralBiologyDMUDepartmentofOralBiologyDMUM近中D远中maxillaryleftmolar(occlusalsurface)上颌第一磨牙上颌第二磨牙DepartmentofOralBiologyDMU颊侧舌侧(proximalsurface)maxillary

molarsfirstmolar第一磨牙Secondmolar第二磨牙BLDepartmentofOralBiologyDMUDepartmentofOralBiologyDMUDifferenceofupperandlowermolarDifferenceofupperandlowermolar1.上斜方，下长2.上直，下歪3.上：颊尖锐，舌尖钝；下：颊尖钝，舌尖锐4.上：3根，下：2根DepartmentofOralBiologyDMUDifferenceofupperandlowermolar上下颌磨牙区别DepartmentofOralBiologyDMU下颌磨牙mandibularmolarDepartmentofOralBiologyDMUDepartmentofOralBiologyDMUDepartmentofOralBiologyDMUBuccalOcclusalDistalMDMDBLDepartmentofOralBiologyDMU舌尖颊尖mandibularfirst

molar(buccalsurface)近中M远中D颊侧（BuccalS）：梯形2个半尖——近中颊尖稍大，远中颊尖，远中尖（颊面与远中面交界处），远中尖颊轴嵴不明显颊沟，远颊沟，颊沟末端形成点隙，外高：颈1/3DepartmentofOralBiologyDMU(lingualsurface)mandibularfirst

molarMD舌面(LingualS)：小，圆突，无明显轴嵴，2舌尖，外高：中1/3

LBLMD邻面（ProximalS）:四边形，牙冠舌倾，颊尖低钝，舌尖高锐，接触区：M:牙合缘偏颊侧D:牙合缘中1/3mandibularmolar(proximalsurface)DepartmentofOralBiologyDMU(occlusalsurface)近中M远中D下颌第一磨牙mandibularfirst

molar牙合面（OcclusalS）:边缘嵴；牙尖：5牙尖，2颊尖低钝，2舌尖高锐，1远中尖位于颊面和远中面拐角处三角嵴：5条，朝向，最长-远中颊尖三角嵴，最短-远中尖斜面：发育沟：5条中央窝：大，在近中2牙尖嵴远中，近中窝：小，三角形中央点隙——颊沟，舌沟，近中沟，远中沟-远颊沟，近中、远中点隙窝(Fossa)DepartmentofOralBiologyDMU沟的走行DMMid-rootsection牙根（Root）：双根，扁而厚，根干短，近中根稍大>远中根远中根22%分为颊舌两根，远中舌根短小弯曲DepartmentofOralBiologyDMUBuccalOcclusalDistalMDMDBLDepartmentofOralBiologyDMUDepartmentofOralBiologyDMUDepartmentofOralBiologyDMUmandibularmolars(occlusalsurface)近中Ｍ远中Ｄ下颌第二磨牙下颌第一磨牙4尖型（55%），5尖型（45%）,比下6稍小，离体不易区分。“田”字型或“+”字型发育沟牙根：相距较近

极少数(3%)分叉为三根：近颊，近舌，远中根C形根：少数近远中根颊侧融合，舌侧仍分开，牙根横断面呈C形，根管亦在颊侧连通，C形根管10%DepartmentofOralBiologyDMUmandibularmolar(proximalsurface)下颌第一磨牙下颌第二磨牙LB沟(Groove）

：田或“+”3颊尖MB,DB,Distal2颊尖MBandDB下颌磨牙DepartmentofOralBiologyDMUDepartmentofOralBiologyDMUDepartmentofOralBiologyDMUDepartmentofOralBiologyDMUDepartmentofOralBiologyDMUDepartmentofOralBiologyDMU一夜小楼听春雨DepartmentofOralBiologyDMUThirdmolar8了解考试不考，拔了不用镶形态数量变异多数量：有上无下；有下无上；都缺如；标准形态类似于7牙合面副沟多，外形高点在中1/3，各轴面中1/3圆突根绝大多数是融合的，2-3个根，也有分叉成多根者DepartmentofOralBiologyDMUDepartmentofOralBiologyDMUDepartmentofOralBiologyDMUDepartmentofOralBiologyDMU应用解剖1.位置重要：咬合、修复、骨折、正畸的参照点。2.口腔内科：萌出早，自洁差，易龋坏。3.口腔外科：第三磨牙智齿冠周炎、阻生。与上颌窦和下颌管关系拔牙4.第一恒磨牙与第二乳磨牙相近5.解剖标志：腮腺导管口和腭大孔