mod morphology of deciduous dentition

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  • MORPHOLOGY OF DECIDUOUS TEETH

  • Deciduous dentition Set traitsSmaller in sizeSmaller crown height/tooth length ratioGreater crown width/height ratio

  • Set traitsMore bulging B & L cervical ridges Constricted cervixBuccal cervical ridges on deciduous molars Occlusal aspect: constricted occlusal table

  • Deciduous dentitionSet traits

    Molar rootsMore slender & relatively longer More bowed & flared outwardShorter root trunkMilk-white in colorEnamel is thinner & pulp chamber is largeSome class, arch & type traits in permanent dentition are applied to deciduous dentitionOnly new traits will be discussed

  • Pulp chamber deciduous v/s permanent teeth

  • Dental formula

  • Deciduous teeth

  • Deciduous incisorsEruption

    Mandibular before maxillary incisorsCentral before lateral incisorsNo mamelons, labial grooves or lobes

  • Maxillary Central incisor

    UNS--------------------E| |FFDI--------------------- 51, 61Eruption time------- 7.5months(FULLER)Order----------------- 1Shedding----------- 6-7 years

  • Maxillary Central incisorIncreased mesiodistal width of crown.Rounded mesioincisal and distoincisal angle than permanent successor.No mamelons on incisal surface+ flat incisal surfaceNo labial grooves, depressions or lobesPronounced bulge on labial surface.

  • Maxillary Central incisorProminent cingulum.Prominent marginal ridgesDeeper lingual fossa.No lingual pit

  • Maxillary Central incisorMESIAL 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 angleMarginal ridges on lingual surface more prominentDeeper lingual fossa.Lingual fossa is deep

  • Maxillary lateral incisor Incisal aspect Much narrower

    mesiodistal dimensionmore rhomboidal & more convex.

  • Maxillary lateral incisorROOTLateral 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 incisorChisel shape incisor morphologySharp 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 crownBulge 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 incisorStraight incisal edgeDivides 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 incisorUNS--------------------Q , NFDI--------------------- 82, 72Eruption time------- 7 MONTHSOrder----------------- 2Shedding------------ 7-8 years

  • Mandibular lateral incisorSimilar 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 incisorIncisal aspect: crown not symmetrical.Cingulum bulges towards distal.

  • Mandibular lateral incisorSingle rootLonger root than central incisorDistal curvature apically.Distal longitudinal groove.

  • Maxillary canineUNS--------------------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 canineWell developed cingulum.Prominent marginal ridges.ML and DL fossae are presentTubercle often present on the cingulum extending from the cusp tip to cingulum.

  • Maxillary canineMesial aspect :Triangular in shapeLabial margin convex incisocervicallyLingual margin concave in incisal half and convex in cervical halfLabiolingually tooth is thickerCervical line depth less

  • Maxillary canine Distal AspectSimilar to mesial except that cervical line shows less curvature.Incisal aspectRhomboidal outlineExhibits 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 canineUNS-------------------- 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 canineSingle but shorter root.

  • Maxillary deciduous molars

  • Maxillary 1st molarUNS-------------------- B(rt) ,I(lt)FDI--------------------- 54, 64Eruption time------- 14 MONTHSOrder----------------- 3Shedding------------ 9-11 years

  • Maxillary 1st molarMost atypical of all primary or permanent molarsCrown doesnot resemble any other primary or permanent molar crown.Exhibit some similarities to the crowns of permanent premolars

  • Maxillary 1st molar BUCCAL ASPECTMD diameter greater than crown heightMesial 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 toothDepth 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 ASPECTLingual surface shorter mesiodistally than buccal surface.ML cusp quite bulky and dominates the occlusal outlineDL 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 molarMESIAL ASPECTDisparity 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 AspectBuccal 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 molarsOcclusal outline MB+ ML cusps and mesial marginal ridge make up the occlusal outline.ML cusp more generous in height than MB cusp.

  • Maxillary 1st molarMESIAL 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 ASPECTunusual five sided figure Cusps: 4 cusps 1) MB cusp