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MORPHOLOGY OF DECIDUOUS TEETHMORPHOLOGY OF DECIDUOUS TEETH
Deciduous dentition Set traits
Smaller in size Smaller crown height/tooth length ratio Greater crown width/height ratio
Set traits More bulging B & L cervical ridges
Constricted cervix Buccal cervical ridges on deciduous
molars Occlusal aspect: constricted occlusal table
Deciduous dentition
Set traits Molar roots
• More slender & relatively longer • More bowed & flared outward• Shorter root trunk
Milk-white in color Enamel is thinner & pulp chamber is large
Some class, arch & type traits in permanent dentition are applied to deciduous dentition
Only new traits will be discussed
Pulp chamber deciduous v/s permanent teeth
Dental formula
Deciduous teeth
Deciduous incisorsEruption
Mandibular before maxillary incisors Central before lateral incisors
No mamelons, labial grooves or lobes
Maxillary Central incisor
UNS--------------------E| |FFDI--------------------- 51, 61Eruption time------- 7.5months(FULLER)Order----------------- 1Shedding----------- 6-7 years
Maxillary Central incisor Increased mesiodistal width of
crown.Rounded mesioincisal and
distoincisal angle than permanent successor.
No mamelons on incisal surface+ flat incisal surface
No labial grooves, depressions or lobes
Pronounced bulge on labial surface.
Maxillary Central incisorProminent cingulum.Prominent marginal
ridgesDeeper lingual fossa.No lingual pit
Maxillary Central incisor MESIAL ASPECT: wider
labiolingually Cervical line exhibits less
curvature incisally. DISTAL ASPECT: Cervical line curvature
less on distal surface as compared to mesial surface.
Maxillary Central incisor
Incisal AspectStraight incisal edgeDivides the crown into
equal labial and lingual portions.
Greater mesiodistal width.
Maxillary Central incisorSingle rootTapers evenly to the
apexRoot longer reltive to
crown length.
Maxillary lateral incisor
UNS--------------------D| |GFDI--------------------- 52, 62Eruption time------- 9 months(FULLER)Order----------------- 2Shedding------------ 7 -8 yrs
Maxillary lateral incisorMuch smaller than central
(trapezoidal labially, triangular proximal aspect)
Crown is wider incisocervically than mesiodistally.
Distoincisal angle more rounded than mesioincisal angle
Marginal ridges on lingual surface more prominent
Deeper lingual fossa.Lingual fossa is deep
Maxillary lateral incisor
Incisal aspect Much narrowermesiodistal dimensionmore rhomboidal &
more convex.
Maxillary lateral incisor
ROOTLateral incisor root
relatively longerApex not so rounded.
Mandibular teeth
Mandibular central incisor
UNS-------------------- P, OFDI--------------------- 81, 71Eruption time------- 6 months(FULLER)Order----------------- 1Shedding------------ 6-7 yrs
Mandibular central incisor
Chisel shape incisor morphology Sharp mesioincisal and distoincisal
angles to the cervial line(90 DEGREES) Incisal margin straight,no mamelons. Smooth labial surface lacking
developmental depressions. Flatter than labial surface of permanent
incisors. Labially symmetrical crown Bulge on labial surface at CEJ.
Mandibular central incisorWell developed
lingual cingulumLess defined marginal
ridges than those of maxillary deciduous central incisor.
Shallow lingual fossa
Mandibular central incisor
Proximal aspect;Triangular in shape/ wedge shaped when seen from mesial or
distal aspect. Incisal edge located over root centre.Cervical line contour evenly curved towards incisal.Greater labiolingual width than that of permanent incisors.Distal aspect shows less depth of curvature towards incisal.
Mandibular central incisor Straight incisal edge Divides the labial and
lingual portions of the crown into nearly equal halves.
In deciduous maxillary central incisor the crown is wider MD.
M & D portions of crown symmetrical
Mandibular central incisorSingle ,long ,slender Convex labial and
lingual surfaces.Flattened mesial and
distal surfaces.
Mandibular lateral incisor
UNS--------------------Q , NFDI--------------------- 82, 72Eruption time------- 7 MONTHSOrder----------------- 2Shedding------------ 7-8 years
Mandibular lateral incisor Similar in form to
deciduous central incisor. Distoincisal angle is
rounded, mesioincisal angle is sharp.
Labial/lingual aspect: Incisal outline slopes slightly
towards the distal
Mandibular lateral incisorLingual AspectCingulum and
marginal ridges little larger.
Lingual fossa little deeper.
Mandibular lateral incisor Incisal aspect: crown
not symmetrical.Cingulum bulges
towards distal.
Mandibular lateral incisorSingle rootLonger root than
central incisorDistal curvature
apically.Distal longitudinal
groove.
Maxillary canine
UNS--------------------C (rt) , H(lt)FDI--------------------- 53, 63Eruption time------- 19 MONTHSOrder----------------- 4Shedding------------ 10-12 years
Maxillary canineMD width > crown
height(Incisocervical measurement)Labial or lingual views: diamond in
shapeRounder mesial and distal outlines.M & D outlines overhang the cervical
line.M& D contact areas located at the
same level incisocervically.Mesial cusp slope longer than distal
cusp slope.No labial ridge or depressionsNo imbrication lines.
Maxillary canine Well developed cingulum. Prominent marginal
ridges. ML and DL fossae are
present Tubercle often present on
the cingulum extending from the cusp tip to cingulum.
Maxillary canine Mesial aspect :Triangular
in shape Labial margin convex
incisocervically Lingual margin concave in
incisal half and convex in cervical half
Labiolingually tooth is thicker
Cervical line depth less
Maxillary canine Distal Aspect Similar to mesial except
that cervical line shows less curvature.
Incisal aspect Rhomboidal outline Exhibits more rounding
incisal than the permanent canine.
Cusp tip offset to distal. Mesial cusp ridge
therefore longer.
Maxillary canineROOTSingle root Root approx twice the
length of crownWider labiolingually
than mesiodistally.
Mandibular canine
UNS-------------------- R ,MFDI--------------------- 83, 73Eruption time------- 16 MONTHSOrder----------------- 4Shedding------------ 9-12 years
Mandibular canineSmaller and slimmer
overall than the maxillary deciduous canine.
MD width of mandibular primary canine< MD width of maxillary pri canine.
Incisocervical ht> MD Width.
Mandibular canineDistoincisal slope
longer than mesioincisal slope(reverse of max.dec canine)
Mandibular canineLL diameter < that of
deciduous max. canine( much narrower tooth labiolingually)
Less pronounced cingulum, MR & cervical ridges.
Shallower fossae than max canine.
Mandibular canine
Single but shorter root.
Maxillary deciduous molars
Maxillary 1st molar
UNS-------------------- B(rt) ,I(lt)FDI--------------------- 54, 64Eruption time------- 14 MONTHSOrder----------------- 3Shedding------------ 9-11 years
Maxillary 1st molar Most atypical of all primary or permanent molars Crown doesnot resemble any other primary or permanent
molar crown. Exhibit some similarities to the crowns of permanent
premolars
Maxillary 1st molar BUCCAL ASPECT MD diameter greater than
crown height Mesial and distal outlines
are convex ,constricted towards cervix.
Comparatively straight occlusal outlinetwo buccal cusps not sharp or prominent.
Maxillary 1st molar Essential difference from permanent
tooth Depth of curvature is much greater
towards the mesial than distal. Buccal surface smooth and lacks
grooves or depressions. MOLAR TUBERCLE OF
ZUCKERKANDL; pronounced bulge on mesial surface of buccal surface.
Flat surface occlusally
Maxillary 1st molar LINGUAL ASPECT Lingual surface shorter
mesiodistally than buccal surface.
ML cusp quite bulky and dominates the occlusal outline
DL cusp is so diminitive that DB CUSP is also partially visible from this aspect.
Maxillary 1st molar
LINGUAL ASPECT Cervical line is evenly
and slightly curved towards cervix.
Convex & smooth surface ,lacking grooves or depressions.
Maxillary 1st molar MESIAL ASPECT Disparity b/w the buccolingual
widths at its cervical and occlusal margins much more than in max.first permanent molars.
Wider dimension cervically due to prominent cervical ridge on buccal and greater taper of buccal and lingual outlines towards occlusal.
Maxillary 1st molar Mesial Aspect Buccal outline dominated by
cervical ridge and crest of curvature is in cervical third.Remainder of buccal outline straight.
Lingual outline convex.More cervically located crest of curvature than in permanent molars
Occlusal outline MB+ ML cusps and mesial marginal ridge make up the occlusal outline.
ML cusp more generous in height than MB cusp.
Maxillary 1st molar
MESIAL ASPECTCervical line slightly
curved towards occlusal.
Maxillary 1st molar Distal AspectConsiderably smaller than the mesial surface.Tapering of buccal surface towards the distal therefore much of the buccal surface visible from
distal aspect.DB cusp more prominent than minute DL cusp.Distal marginal ridge less pronounced than mesial
marginal ridge.Cervical line is straight to slightly curved
occlusally.
Maxillary 1st molar
OCCLUSAL ASPECT unusual five sided figure Cusps: 4 cusps 1) MB cusp 2) DB cusp 3) ML cusp 4) DL cusp
Maxillary 1st molarMesiolingual cuspLargest cusp and
longest.Mesiobuccal cuspMB cusp greater than
distobuccal.Distobuccal cuspDistolingual cuspSmallest cusp.
Maxillary 1st molar Transverse ridge:
prominent T-ridgeFormed by lingual
cusp ridge of MB cusp and buccal cusp ridge of ML cusp.
Oblique RidgeExtends from ML cusp
to DB cusp.
Maxillary 1st molar
Fossae: 3 fossae 1) central fossa 2) mesial triangular fossa 3) distal triangular fossa
Maxillary 1st molar ROOTS no root trunk. Root trunk: defined as that
portion of root situated b/w cervical line and the point of furcation.
Three roots: 1) MB root 2) DB ROOT 3) Palatal root Slender and flared roots Largest +longest palatal
root.
Maxillary 2nd molar
UNS-------------------- A,JFDI--------------------- 55, 65Eruption time------- 24 MONTHSOrder----------------- 5Shedding------------ 10-12 years
Maxillary 2nd molar Primary maxillary second
molar larger than primary maxillary first molar
Closely resembles the permanent maxillary first molar in form but is smaller in all dimensions.
Usually has a Cusp of Carabelli ,as its permanent counterpart.
Mandibular 1st molar
UNS-------------------- L &SFDI--------------------- 84, 74Eruption time------- 12 MONTHSOrder----------------- 3Shedding------------ 9-11 years
Mandibular 1st molar Primary mandibular first
molar has crown unlike any tooth of either dentition.
Prominent buccal cervical ridge on mesial half of buccal surface.
The HOC on the buccal is at cervical one third
The HOC on the lingual is in the middle one third.
Mandibular 1st molar CUSPS: 4 cusps:1)MB 2) ML 3) DB 4) DL
The two mesial cusps are considerably larger than distal cusps.
Mandibular 1st molarA transverse ridge
passes b/w the mesiobuccal and mesiolingual cusps.
Mandibular 1st molar
Roots2 roots i.e mesial and
distal .Mesial wider than
distal root.
Mandibular 2nd molar
UNS-------------------- K&TFDI--------------------- 85, 75Eruption time------- 20 MONTHSOrder----------------- 5Shedding------------ 10-12 years
Larger than the primary mandibular first molar.
This tooth closely resembles the permanent mandibular first molar, disregarding size and general differences.
5 cusps similar to permanent mand first molar.
Mandibular 2nd molar
Mandibular 2nd molar Major differences are: The 3
buccal cusps (MB,DB& distal) are nearly equal in size.
Occlusa table relatively longer buccolingually and less pentagonal than that of the first permanent molar.
The mesial root is longer and wider than the distal root whereas they are of equal length in permanent first molar.
ANY QUESTIONS