Dental Anatomy/Occlusion Dental Anatomy/Occlusion Review for the Review for the NBDENBDE Part IPart I

Presented by:Presented by:Eric WongEric WongKim MaiKim Mai

OverviewOverview

!! 100 Questions100 Questions!! Taken as part of the final 200 questions of the exam Taken as part of the final 200 questions of the exam

(second half of the day)(second half of the day)!! May have some overlapping questions from Anatomy May have some overlapping questions from Anatomy

Section, Section, ieie. TMJ anatomy, muscles of mastication, etc.. TMJ anatomy, muscles of mastication, etc.!! Useful resources: Dental Decks, old exam questions, Useful resources: Dental Decks, old exam questions,

IsselhardIsselhard & Brand’s & Brand’s Anatomy of Orofacial StructuresAnatomy of Orofacial Structures, , Kaplan Part I Review BookKaplan Part I Review Book

Helpful Hint #1Helpful Hint #1!! Write down everything on the margins of the exam Write down everything on the margins of the exam

booklet! (booklet! (ieie. tooth relationships, mnemonics, eruption . tooth relationships, mnemonics, eruption schedules, primary and permanent teeth #s)schedules, primary and permanent teeth #s)

!! Example:Example:

Dental Arch RelationshipsDental Arch Relationships!! The maxillary arch is usually LONGER than the mandibular archThe maxillary arch is usually LONGER than the mandibular arch

!! What does this mean?What does this mean?--Every maxillary tooth is more DISTAL than its opposing counterpaEvery maxillary tooth is more DISTAL than its opposing counterpart, therefore:rt, therefore:1) The only maxillary tooth with 1 opposing counterpart is 1) The only maxillary tooth with 1 opposing counterpart is the the

MAXILLARY THIRD MOLARMAXILLARY THIRD MOLAR2) The only mandibular tooth with 1 opposing counterpart is2) The only mandibular tooth with 1 opposing counterpart is the the

MANDIBULAR CENTRAL INCISORMANDIBULAR CENTRAL INCISOR

Useful DiagramsUseful Diagrams

Dental Arch RelationshipsDental Arch Relationships!! The maxillary arch is usually WIDER than the mandibular archThe maxillary arch is usually WIDER than the mandibular arch

!! Therefore, Supporting (functional) cusps are MAXILLARY Therefore, Supporting (functional) cusps are MAXILLARY LINGUAL and MANDIBULAR BUCCAL cuspsLINGUAL and MANDIBULAR BUCCAL cusps

!! Guiding (nonfunctional, shearing cusps) are MAXILLARY Guiding (nonfunctional, shearing cusps) are MAXILLARY BUCCAL and MANDIBULAR LINGUAL cuspsBUCCAL and MANDIBULAR LINGUAL cusps

Maxillary CuspsMaxillary Cusps

!! Buccal cusps:Buccal cusps:--Premolar cusps and the DB cusp of the maxillary molars Premolar cusps and the DB cusp of the maxillary molars overlapoverlap the the embrassureembrassure between between

the counterpart and the tooth DISTAL to it, the counterpart and the tooth DISTAL to it, exceptexcept for the maxillary 1for the maxillary 1stst and 3and 3rdrd molars molars (DB of maxillary 3(DB of maxillary 3rdrd molar only overlaps 1 tooth) molar only overlaps 1 tooth)

--MB cusps of all maxillary molars overlap the counterpart’s FACIAMB cusps of all maxillary molars overlap the counterpart’s FACIAL groove L groove (MESIOFACIAL groove for 1(MESIOFACIAL groove for 1stst molar, central groove for 2molar, central groove for 2ndnd and 3and 3rdrd molars)molars)

--DB cusp of maxillary 1DB cusp of maxillary 1stst molar overlaps the DISTOFACIAL groove of the mandibular 1molar overlaps the DISTOFACIAL groove of the mandibular 1stst

molarmolar!! Lingual cusps:Lingual cusps:

--22ndnd premolar cusp and the DL cusps of the maxillary molars premolar cusp and the DL cusps of the maxillary molars contactcontact the counterpart’s the counterpart’s distal marginal ridge and the mesial marginal ridge of the toothdistal marginal ridge and the mesial marginal ridge of the tooth DISTAL to it, except for DISTAL to it, except for the 1the 1stst premolar & DL cusp of the max. 3premolar & DL cusp of the max. 3rdrd molar (only contact 1 marginal ridge molar (only contact 1 marginal ridge respectively)respectively)

--ML cusps of maxillary molars contact the counterpart’s CENTRAL FML cusps of maxillary molars contact the counterpart’s CENTRAL FOSSAOSSA!! Question: Which cusps are represented by the arrows?Question: Which cusps are represented by the arrows?

Mandibular CuspsMandibular Cusps

!! Buccal cusps:Buccal cusps:--Premolar cusps and MB cusps of Premolar cusps and MB cusps of mandibuolarmandibuolar molars molars contactcontact the mesial marginal the mesial marginal

ridge of the counterpart and the distal marginal ridge of the toridge of the counterpart and the distal marginal ridge of the tooth MESIAL to itoth MESIAL to it--The DB cusps of the mandibular molars contact the counterpart’s The DB cusps of the mandibular molars contact the counterpart’s CENTRAL CENTRAL

FOSSAFOSSA--The distal cusp of the mandibular 1The distal cusp of the mandibular 1stst molar contacts the maxillary 1molar contacts the maxillary 1stst molar’s molar’s

DISTAL PIT DISTAL PIT !! Lingual cusps:Lingual cusps:

--Premolar cusps and ML cusps of mandibular molars Premolar cusps and ML cusps of mandibular molars overlapoverlap the the embrassureembrassurebetween the counterpart and the tooth MESIAL to itbetween the counterpart and the tooth MESIAL to it

--The DL cusps of the mandibular molars overlap the counterpart’s The DL cusps of the mandibular molars overlap the counterpart’s LINGUAL LINGUAL GROOVEGROOVE

!! Question: Which cusps are represented by the arrows? Question: Which cusps are represented by the arrows?

Jaw MovementsJaw Movements!! ONLY THE MANDIBULAR ARCH MOVES!!!!!!!!!!!ONLY THE MANDIBULAR ARCH MOVES!!!!!!!!!!!!! Working (Working (laterotrusivelaterotrusive) movement = towards the side ) movement = towards the side

that the mandible moves towardsthat the mandible moves towards!! NonNon--working (working (mediotrusivemediotrusive, balancing) movement = , balancing) movement =

NOT the side that the mandible moves towardsNOT the side that the mandible moves towards!! Protrusion = moving the mandible forward in an Protrusion = moving the mandible forward in an

anterioranterior--posterior planeposterior plane!! RetrusionRetrusion = moving the mandible backwards in an = moving the mandible backwards in an

anterioranterior--posterior planeposterior plane

Jaw Movement DiagramsJaw Movement Diagrams

!! Which way is the mandible moving?Which way is the mandible moving?!! Are the teeth on the side that the mandible is Are the teeth on the side that the mandible is

moving towards, or are they not?moving towards, or are they not?!! Isolate the teeth in question!Isolate the teeth in question!

Working movementWorking movement

Right lateral (working side) movment

Right lateral (working side) movement

NOTICE MAXILLARY ARCH DOES NOT MOVE!! (Think in terms of wherethe mandible is moving in relation to the maxillary arch)

Nonworking movementNonworking movement

Left lateral (non-working) movement

Right lateral (non-working) movement

ProtrusionProtrusion

MesioMesio--Distal ContactsDistal Contacts(from facial view)(from facial view)

MMMMJJJJIMIMIIIIIIIIMandibularMandibular

MMMMJJJJJMJMJJJJIJIJMaxillaryMaxillary

MolarsMolarsPremolarsPremolarsCanineCanineLateral Lateral IncisorIncisor

Central Central IncisorIncisor

IJ means the MESIAL contact is located in the incisal third (I) while the DISTAL contact is located at the junction (J) of the incisal/occlusal and middle thirds.

FacioFacio--Lingual ContactsLingual Contacts(from (from incisal/occlusalincisal/occlusal view)view)

!! FacioFacio--Lingual Contacts: Lingual Contacts: 1) CENTERED 1) CENTERED faciolinguallyfaciolingually for all ANTERIOR teethfor all ANTERIOR teeth2) SLIGHTLY BUCCAL of the middle third for all POSTERIOR te2) SLIGHTLY BUCCAL of the middle third for all POSTERIOR teetheth

!! FacioFacio--Lingual Embrasures: Every tooth has a wider LINGUAL embrasure tLingual Embrasures: Every tooth has a wider LINGUAL embrasure than han FACIAL embrasure EXCEPT for the lingual embrasure between the FACIAL embrasure EXCEPT for the lingual embrasure between the MAXILLARY 1MAXILLARY 1stst and 2and 2ndnd MOLAR (less wide), and MANDIBULAR MOLAR (less wide), and MANDIBULAR AnteriorsAnteriors

Heights of ContourHeights of Contour

!! Located in the MIDDLE third of the crown on: Located in the MIDDLE third of the crown on: LINGUAL surfaces of all posterior teeth (both LINGUAL surfaces of all posterior teeth (both maxillary & mandibular) maxillary & mandibular)

!! Located in the CERVICAL third of the crown Located in the CERVICAL third of the crown on: FACIAL surfaces of all posterior teeth, and on: FACIAL surfaces of all posterior teeth, and FACIAL & LINGUAL surfaces of all anterior FACIAL & LINGUAL surfaces of all anterior teethteeth

Tooth EmbryologyTooth Embryology!! 66thth embryonic week = the oral (stratified squamous) epithelium embryonic week = the oral (stratified squamous) epithelium

begins thickening. This thickened oral epithelium is known as begins thickening. This thickened oral epithelium is known as the the dental laminadental lamina..

!! 88thth embryonic week = continued thickening in the dental lamina embryonic week = continued thickening in the dental lamina in 10 areas of the upper arch and 10 areas of the lower archin 10 areas of the upper arch and 10 areas of the lower arch

!! Bud stageBud stage = initial budding from the dental lamina at the 10 = initial budding from the dental lamina at the 10 thickened areas in each arch (the first stage in the developmentthickened areas in each arch (the first stage in the development of of the the enamel organenamel organ))

!! Cap stageCap stage = consists of three components: outer enamel = consists of three components: outer enamel epithelium, inner enamel epithelium, and epithelium, inner enamel epithelium, and stellatestellate reticulumreticulum

!! Bell stageBell stage = fourth layer of epithelium, the stratum = fourth layer of epithelium, the stratum intermediumintermedium, appears between the IEE and the , appears between the IEE and the stellatestellate reticulum. reticulum. Two processes occur: (1) future outline or form of the crown ofTwo processes occur: (1) future outline or form of the crown ofthe tooth is determined (2) changes in IEE lead to production othe tooth is determined (2) changes in IEE lead to production of f dentin and enamel starting with IEE cells becoming taller dentin and enamel starting with IEE cells becoming taller ""secretion of dentin matrix secretion of dentin matrix "" secretion of enamel matrix secretion of enamel matrix ""calcification of dentin calcification of dentin "" calcification of enamel.calcification of enamel.

Tooth EmbryologyTooth Embryology

!! Terminology:Terminology:Dental papillaDental papilla = forms the dentin and pulp of = forms the dentin and pulp of the tooththe toothDental sacDental sac = forms the = forms the cementumcementum of the tooth, of the tooth, the periodontal ligament, and some alveolar bonethe periodontal ligament, and some alveolar boneHertwig’sHertwig’s epithelial root sheathepithelial root sheath = made up of = made up of OEE and IEE that determines the shape of the OEE and IEE that determines the shape of the rootsroots

Primary vs. Permanent TeethPrimary vs. Permanent Teeth!! The crowns of the primary ANTERIOR teeth are The crowns of the primary ANTERIOR teeth are wider wider mesiodistallymesiodistally and shorter and shorter

incisoinciso--cervicallycervically than their permanent than their permanent succesorssuccesors..!! The crowns of the primary MOLARS are shorter and more narrow The crowns of the primary MOLARS are shorter and more narrow mesiodistallymesiodistally at the at the

cervical third than the permanents. The root trunks of primary cervical third than the permanents. The root trunks of primary molars are also very molars are also very short.short.

!! The cervical ridge of enamel at the cervical third is much more The cervical ridge of enamel at the cervical third is much more prominent in primary prominent in primary teeth.teeth.

!! The BUCCAL and LINGUAL surfaces of primary molars are flatter abThe BUCCAL and LINGUAL surfaces of primary molars are flatter above the crest of ove the crest of contour than on permanent molars, giving the appearance of a narcontour than on permanent molars, giving the appearance of a narrower occlusal table.rower occlusal table.

!! The enamel rods on primary teeth point OCCLUSALLY at the cervicaThe enamel rods on primary teeth point OCCLUSALLY at the cervical third, compared l third, compared to APICALLY for permanent teeth (which is why there is no need fto APICALLY for permanent teeth (which is why there is no need for a gingival bevel or a gingival bevel for a Class II amalgam on primary teeth).for a Class II amalgam on primary teeth).

!! The roots of the primary are longer, more slender, and taper morThe roots of the primary are longer, more slender, and taper more rapidly than those of e rapidly than those of the permanent molarsthe permanent molars

!! The pulp horns extend higher The pulp horns extend higher occlusallyocclusally and the pulp chambers are proportionately larger and the pulp chambers are proportionately larger in primary teeth.in primary teeth.

!! The primary teeth are LIGHTER in color than the permanent teeth.The primary teeth are LIGHTER in color than the permanent teeth.!! The MESIAL CUSP RIDGE is longer than the distal cusp ridge in thThe MESIAL CUSP RIDGE is longer than the distal cusp ridge in the PRIMARY e PRIMARY

MAXILLARY CANINE (the opposite is true for all other canines). MAXILLARY CANINE (the opposite is true for all other canines).

Eruption Schedule Eruption Schedule –– Permanent Permanent (in years)(in years)

!! Mandibular 1Mandibular 1stst Molar Molar –– 66!! Maxillary 1Maxillary 1stst Molar Molar –– 66!! MandMand. Central Incisor . Central Incisor –– 66!! Max. Central Incisor Max. Central Incisor –– 77!! MandMand. Lateral Incisor . Lateral Incisor –– 77!! Max. Lateral Incisor Max. Lateral Incisor –– 88!! MandMand. Canine . Canine –– 99!! MandMand. 1. 1stst Premolar Premolar –– 1010!! Max. 1Max. 1stst Premolar Premolar –– 1010!! MandMand. 2. 2ndnd Premolar Premolar –– 1111!! Max. Canine Max. Canine –– 1111!! MandMand. 2. 2ndnd Molar Molar –– 1212!! Max. 2Max. 2ndnd Molar Molar –– 1212!! MandMand. 3. 3rdrd Molar Molar –– 1717--2121!! Max. 3Max. 3rdrd Molar Molar –– 1717--2121

Eruption Schedule Eruption Schedule -- PrimaryPrimary!! Central Incisor Central Incisor –– 7 months7 months!! Lateral Incisor Lateral Incisor –– 11 months11 months!! First Molar First Molar –– 15 months15 months!! Canine Canine –– 19 months19 months!! Second Molar Second Molar -- 23 months23 months

** Rule of 4’sRule of 4’s (every 4 months another one erupts)(every 4 months another one erupts)** Mandibular teeth usually erupt before their maxillary Mandibular teeth usually erupt before their maxillary

counterpart.counterpart.

Dental AnomaliesDental Anomalies!! MacrodontiaMacrodontia = teeth are too large= teeth are too large!! MicrodontiaMicrodontia = teeth are too small= teeth are too small!! HyperdontiaHyperdontia = multiple or extra teeth (called supernumeraries)= multiple or extra teeth (called supernumeraries)!! AnondontiaAnondontia = no teeth= no teeth!! Dens in dente = outer surface of the tooth crown Dens in dente = outer surface of the tooth crown invaginatesinvaginates or or

turns itself inward before mineralization (most frequently affecturns itself inward before mineralization (most frequently affects ts permanent maxillary lateral incisorspermanent maxillary lateral incisors))

!! DilacerationDilaceration = tooth that has a sharp bend or curve in the root or = tooth that has a sharp bend or curve in the root or crowncrown

!! GeminationGemination = tooth attempts to divide itself or partially twin itself = tooth attempts to divide itself or partially twin itself by splitting its tooth germby splitting its tooth germ

!! Fusion = two adjacent tooth germs uniteFusion = two adjacent tooth germs unite!! ConcresenceConcresence = fusion of = fusion of cementumcementum of the rootsof the roots!! HypercementosisHypercementosis = deposition of excessive amounts of secondary = deposition of excessive amounts of secondary

cementumcementum

Dental AnomaliesDental Anomalies!! Enamel pearls = small masses of excess enamel on the surface of Enamel pearls = small masses of excess enamel on the surface of

teeth located APICALLY to the CEJteeth located APICALLY to the CEJ!! Hutchinson’s incisors & Mulberry molars = irregularlyHutchinson’s incisors & Mulberry molars = irregularly--shaped shaped

teeth as a result of teeth as a result of congenital syphiliscongenital syphilis!! Enamel dysplasia = interruption of enamel formationEnamel dysplasia = interruption of enamel formation!! Enamel Enamel hypocalcificationhypocalcification = caused by a condition that inhibits = caused by a condition that inhibits

the calcification of enamelthe calcification of enamel!! Turner’s tooth = Turner’s tooth = hypocalcificationhypocalcification of a single tooth, usually a of a single tooth, usually a

maxillary incisormaxillary incisor!! Enamel lamellae = cracks in the Enamel lamellae = cracks in the enamelenamel caused by developmental caused by developmental

problems or traumaproblems or trauma!! Enamel tuft = small area of Enamel tuft = small area of hypocalcifiedhypocalcified enamel seen enamel seen at the DEJat the DEJ

and extending about one fourth to one third of the way through and extending about one fourth to one third of the way through the enamelthe enamel

!! Enamel spindle = an Enamel spindle = an odontoblasticodontoblastic processprocess that ends up in the that ends up in the enamelenamel

Posselt’sPosselt’s Envelope of MotionEnvelope of Motion1 = Maximum Protrusion (Protruded 1 = Maximum Protrusion (Protruded

contact position)contact position)2 = Edge to edge position of incisors2 = Edge to edge position of incisors3 = Centric Occlusion (Maximum 3 = Centric Occlusion (Maximum

IntercuspationIntercuspation))4 = Centric Relation (4 = Centric Relation (RetrudedRetruded

contact position)contact position)Dot = Rest positionDot = Rest position5 = Chewing stroke5 = Chewing stroke6 = Rotation (Terminal Hinge Axis 6 = Rotation (Terminal Hinge Axis

opening) opening) 7 = Translation7 = Translation8 = Maximum opening8 = Maximum opening

TMJ AnatomyTMJ Anatomy

TMJ AnatomyTMJ Anatomy!! Upper compartment (Upper compartment (concavoconvexconcavoconvex) = Space between ) = Space between

articulararticular disc and temporal bone. Permits disc and temporal bone. Permits TRANSLATIONAL movements.TRANSLATIONAL movements.

!! Lower compartment (concave) = Space between Lower compartment (concave) = Space between articulararticulardisc and mandibular disc and mandibular condylecondyle. Permits ROTATIONAL . Permits ROTATIONAL movements.movements.

!! Movement on opening = Movement on opening = rotationrotation occurs first, occurs first, thenthentranslationtranslation

!! The The articulararticular disc is disc is avascularavascular and is thickest at the and is thickest at the posterior section, followed by the anterior, and thinnest in posterior section, followed by the anterior, and thinnest in the middlethe middle

!! The The retrodiscalretrodiscal padpad is an area where much of the blood is an area where much of the blood and nerve supply to the joint is foundand nerve supply to the joint is found

Muscles of MasticationMuscles of Mastication

Neck of the Neck of the condylecondyleLateral side of the lateral Lateral side of the lateral pterygoidpterygoid plateplate

Lateral Lateral PterygoidPterygoid (inferior head)(inferior head)

Capsule & Capsule & articulararticular disk of disk of temporomandibular joint temporomandibular joint

InfratemporalInfratemporal crest of the greater crest of the greater wing of the sphenoid bonewing of the sphenoid bone

Lateral Lateral PterygoidPterygoid (superior head)(superior head)

Medial surface of Medial surface of ramusramus and angle and angle on the medial sideon the medial side

Larger origin = medial side of the Larger origin = medial side of the lateral lateral pterygoidpterygoid plate and plate and

pterygoidpterygoid fossafossa & tiny area of the & tiny area of the palatine bone palatine bone

Smaller origin = maxillary Smaller origin = maxillary tuberositytuberosity

Medial Medial PterygoidPterygoid

CoronoidCoronoid process and anterior process and anterior border of the border of the ramusramus

Temporal Temporal fossafossa and temporal and temporal fascia fascia

TemporalisTemporalis

Lateral surface of Lateral surface of ramusramusInferior border of the posterior Inferior border of the posterior one third of the one third of the zygomaticzygomatic arch arch

and the entire medical side of the and the entire medical side of the zygomaticzygomatic archarch

MasseterMasseter (deep head)(deep head)

Angle of the mandible on the Angle of the mandible on the lateral sidelateral side

Inferior border of the anterior Inferior border of the anterior two thirds of the two thirds of the zygomaticzygomatic archarch

MasseterMasseter (superficial head)(superficial head)

InsertionInsertionOriginOriginMuscleMuscle

Maxillary Central IncisorMaxillary Central IncisorPermanentPermanent

!! CrownCrown!! Longest and widest anterior toothLongest and widest anterior tooth!! Crown wider Crown wider mesialmesial--distally (Mdistally (M--D) than FacialD) than Facial--LinguallyLingually (F(F--

L)L)!! Root = oneRoot = one

!! Cervical dimension MCervical dimension M--D approximately equal to FD approximately equal to F--LL!! SurfacesSurfaces

!! Mesial curvature of cervical line is largestMesial curvature of cervical line is largest!! CingulumCingulum located offlocated off--center toward distalcenter toward distal!! Narrowest incisal embrasuresNarrowest incisal embrasures!! 3 3 mamelonsmamelons and 4 developmental groovesand 4 developmental grooves

Maxillary Lateral IncisorMaxillary Lateral IncisorPermanentPermanent

!! CrownCrown!! MM--D > FD > F--L (just like the max central incisor)L (just like the max central incisor)

!! RootRoot!! One, pointed apex, deviates to distalOne, pointed apex, deviates to distal

!! SurfaceSurface!! Lingual pit is commonLingual pit is common!! Lingual surface most concave of any incisorsLingual surface most concave of any incisors

!! NotesNotes!! May be congenitally absentMay be congenitally absent!! May appear pointed (“peg shaped”)May appear pointed (“peg shaped”)

Maxillary CanineMaxillary CaninePermanentPermanent

!! CrownCrown!! CingulumCingulum large and centered Mlarge and centered M--DD!! Wider FWider F--L than ML than M--DD

!! RootRoot!! Longest rootLongest root

!! CuspCusp!! Mesial cusp ridge is shorter than distal cusp ridgeMesial cusp ridge is shorter than distal cusp ridge

!! NotesNotes!! Most stable and self cleansing toothMost stable and self cleansing tooth!! Least often extracted toothLeast often extracted tooth

Maxillary First PremolarMaxillary First PremolarPermanentPermanent

!! CrownCrown!! Widest of all premolarsWidest of all premolars!! Greater BGreater B--L than ML than M--DD!! Longer Longer occlusooccluso--gingivallygingivally than all posterior maxillary teeththan all posterior maxillary teeth

!! RootsRoots!! 2 roots (only premolar with two roots)2 roots (only premolar with two roots)

!! CuspsCusps!! Lingual cusp shorter than buccal cuspLingual cusp shorter than buccal cusp!! Buccal cusp tip placed slightly distalBuccal cusp tip placed slightly distal!! Mesial buccal cusp ridge is longer than distal buccal cusp ridgeMesial buccal cusp ridge is longer than distal buccal cusp ridge!! Lingual cusp tip located toward mesial half of lingual surfaceLingual cusp tip located toward mesial half of lingual surface

!! SurfaceSurface!! Mesial surface has pronounced (deep) cervical concavityMesial surface has pronounced (deep) cervical concavity

!! OcclusalOcclusal!! Long central groove, deep Long central groove, deep sulcussulcus, no pits, no pits

Maxillary 2Maxillary 2ndnd PremolarPremolarPermanentPermanent

!! CrownCrown!! Smaller than maxillary 1Smaller than maxillary 1stst premolarpremolar!! More symmetrical and less angular (more ovoid) than 1More symmetrical and less angular (more ovoid) than 1stst premolarpremolar

!! Root = oneRoot = one!! CuspCusp

!! Two cusps, buccal and lingual cusps are equal in heightTwo cusps, buccal and lingual cusps are equal in height!! Mesial inclination of lingual cuspMesial inclination of lingual cusp!! Distal buccal cusp ridge is longer than mesial buccal cusp ridgeDistal buccal cusp ridge is longer than mesial buccal cusp ridge (opposite of (opposite of

maxillary first premolar)maxillary first premolar)!! SurfacesSurfaces

!! No mesial developmental depressionNo mesial developmental depression!! Less prominent buccal ridgeLess prominent buccal ridge

!! OcclusalOcclusal patternpattern!! Shorter central groove with more supplemental groovesShorter central groove with more supplemental grooves

Maxillary 1Maxillary 1stst MolarMolarPermanentPermanent

!! CrownCrown!! Largest permanent toothLargest permanent tooth!! Broader Broader linguallylingually than than buccallybuccally

!! Roots = 3Roots = 3!! Cusps Cusps

!! 4 (2 buccal, 2 lingual)4 (2 buccal, 2 lingual)!! MesialMesial--lingual always largest and highest on any posterior toothlingual always largest and highest on any posterior tooth!! Cusp of Cusp of carabellicarabelli seen lingual to mesialseen lingual to mesial--lingual cusplingual cusp!! MesialMesial--buccal longer and wider than Distalbuccal longer and wider than Distal--buccalbuccal

!! OcclusalOcclusal!! Oblique ridge connects the mesialOblique ridge connects the mesial--lingual cusp and distallingual cusp and distal--buccal cuspbuccal cusp!! OcclusalOcclusal view of all maxillary molars = rhomboidal shapeview of all maxillary molars = rhomboidal shape!! Rhomboidal shaped Rhomboidal shaped occlusalocclusal view with obtuse angles at mesialview with obtuse angles at mesial--lingual and distallingual and distal--buccalbuccal

!! SurfaceSurface!! Distal surface Distal surface –– pronounced cervical concavitypronounced cervical concavity!! Long buccal groove with pitLong buccal groove with pit

Maxillary 2Maxillary 2ndnd MolarMolarPermanentPermanent

!! CrownCrown!! Smaller than 1Smaller than 1stst molarmolar!! MesialMesial--facial line angle most acutefacial line angle most acute!! Absence of 5Absence of 5thth cusp (cusp (carabellicarabelli))

!! Root = 3Root = 3!! CuspCusp

!! mesialmesial--lingual cusp largestlingual cusp largest!! Primary cusp triangle = mesialPrimary cusp triangle = mesial--lingual, mesiallingual, mesial--buccal, and distalbuccal, and distal--buccal buccal

cusps (same for all maxillary molars)cusps (same for all maxillary molars)!! Buccal groove does not have a pitBuccal groove does not have a pit

!! NotesNotes!! Small distalSmall distal--lingual cusp that can be absent creating a 3 cusp toothlingual cusp that can be absent creating a 3 cusp tooth

Mandibular Central IncisorMandibular Central IncisorPermanentPermanent

!! CrownCrown!! Nearly bilaterally symmetricalNearly bilaterally symmetrical!! MesialMesial--incisalincisal and distaland distal--incisalincisal angles are sharp, nearly at right anglesangles are sharp, nearly at right angles

!! Root = oneRoot = one!! Thin MThin M--D and wide FD and wide F--LL!! Mesial and distal surface concave (also present on mandibular laMesial and distal surface concave (also present on mandibular laterals)terals)

!! SurfaceSurface!! CingulumCingulum –– centeredcentered!! Lingual surface smooth and shallowLingual surface smooth and shallow!! No grooves, accessory ridges or pitsNo grooves, accessory ridges or pits

!! NotesNotes!! Mesial and distal contacts are exactly the same area of the inciMesial and distal contacts are exactly the same area of the incisal third sal third

(unique to mandibular central incisors)(unique to mandibular central incisors)

Mandibular Lateral IncisorsMandibular Lateral IncisorsPermanentPermanent

!! CrownCrown!! Tilted distally on the rootTilted distally on the root!! Broader Broader labiolinguallylabiolingually than than mesiodistallymesiodistally

!! Root = oneRoot = one!! Narrow MNarrow M--DD!! Concavities on MConcavities on M--D surfacesD surfaces

!! SurfacesSurfaces!! CingulumCingulum offoff--center to the distalcenter to the distal!! Mesial marginal ridge is slightly longer than distal marginal Mesial marginal ridge is slightly longer than distal marginal

ridgeridge

Mandibular CanineMandibular CaninePermanentPermanent

!! CrownCrown!! Longest crown of all permanent teethLongest crown of all permanent teeth!! FF--L > ML > M--DD

!! Root = oneRoot = one!! May be bifurcatedMay be bifurcated

!! CuspCusp!! Cusp tip displaced Cusp tip displaced linguallylingually!! Mesial cusp ridge shorter than distal cusp ridge (just like Mesial cusp ridge shorter than distal cusp ridge (just like

maxillary canine)maxillary canine)!! SurfacesSurfaces

!! Mesial surface of crown almost parallel to long axis of toothMesial surface of crown almost parallel to long axis of tooth

Mandibular 1Mandibular 1stst PremolarPremolarPermanentPermanent

!! CrownCrown!! More prominent buccal ridge than 2More prominent buccal ridge than 2ndnd premolarpremolar!! Bell shaped crownBell shaped crown

!! Root = oneRoot = one!! Pointed apexPointed apex!! No distal curvatureNo distal curvature!! Many have concavities on mesial and distalMany have concavities on mesial and distal

!! CuspCusp!! Large pointed buccal cuspLarge pointed buccal cusp!! Small Small nonfuctioningnonfuctioning lingual cusplingual cusp!! High buccal and low lingual pulp hornsHigh buccal and low lingual pulp horns

!! OcclusalOcclusal patternpattern!! Small, nonfunctioningSmall, nonfunctioning!! Usually no central grooveUsually no central groove

Mandibular 2Mandibular 2ndnd PremolarPremolarPermanentPermanent

!! CrownCrown!! 5 lobes (Y type) 3 cusps, one buccal and 2 ling5 lobes (Y type) 3 cusps, one buccal and 2 ling!! Square Square occlusalocclusal outlineoutline

!! Root = oneRoot = one!! Apex approximates mental foramenApex approximates mental foramen!! Thicker and longer than mandibular 1Thicker and longer than mandibular 1stst premolarpremolar

!! CuspCusp!! MesialMesial--lingual cusp always larger than distallingual cusp always larger than distal--lingual cusplingual cusp

!! Pits and groovesPits and grooves!! Central developmental groove “U” shaped or like a crescentCentral developmental groove “U” shaped or like a crescent!! MesialMesial--distal distal fossaefossae

!! OcclusalOcclusal pattern pattern !! Larger Larger occlusalocclusal surface than 1surface than 1stst mandibular premolarmandibular premolar!! No mesialNo mesial--lingual groove or transverse ridge (common on 1lingual groove or transverse ridge (common on 1stst mandibular mandibular

premolars)premolars)!! 3 types of 3 types of occlusalocclusal surface = Y, H, U typesurface = Y, H, U type

Mandibular 1Mandibular 1stst MolarMolarPermanentPermanent

!! CrownCrown!! Largest mandibular toothLargest mandibular tooth!! Largest mesialLargest mesial--distal dimension of any toothdistal dimension of any tooth!! OcclusalOcclusal outline = similar to a trapezoidoutline = similar to a trapezoid

!! Root = 2Root = 2!! Two roots with 3 canals (2Two roots with 3 canals (2ndnd canal in mesial root)canal in mesial root)

!! CuspsCusps!! 5 (3buccal; 2 lingual), mesial5 (3buccal; 2 lingual), mesial--buccal cusp is largestbuccal cusp is largest!! Distal cusp = smallestDistal cusp = smallest!! Lingual cusp are higher and more pointed (nonLingual cusp are higher and more pointed (non--supporting) than buccal cusp supporting) than buccal cusp

(supporting)(supporting)!! OcclusalOcclusal patternpattern

!! 2 transverse ridges, 3 2 transverse ridges, 3 fossaefossae with pitswith pits!! Central groove crookedCentral groove crooked!! 2 buccal grooves2 buccal grooves

Mandibular 2Mandibular 2ndnd MolarMolarPermanentPermanent

!! Crown Crown !! OcclusalOcclusal outline is rectangularoutline is rectangular

!! Roots = 2Roots = 2!! Closer together and straighter than first mandibular molar rootsCloser together and straighter than first mandibular molar roots!! Mesial root not as broad FMesial root not as broad F--L compared to 1L compared to 1stst mandibular molarmandibular molar!! Longer root trunk than mandibular 1Longer root trunk than mandibular 1stst molarmolar!! Apices are located inferiorly to Apices are located inferiorly to mylohyoidmylohyoid muscle insertionmuscle insertion

!! Cusps = 4Cusps = 4!! OcclusalOcclusal patternpattern

!! Plus sign (+)Plus sign (+)!! More secondary developmental grooves than 1More secondary developmental grooves than 1stst mandibular molarmandibular molar!! 2 transverse ridges2 transverse ridges!! 3 3 fossaefossae with pitswith pits

!! Buccal groove with buccal pitBuccal groove with buccal pit