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THEDECIDUOUSDENTITION INTRODUCTION TheworddeciduouscomesfromaLatinwordmeaningtofalloff Deciduousteethfallofforareshedlikeleavesfromadeciduoustree Thedeciduous primary or astheyoftenreferredtocolloquially MILK teeth havearelativelyshortlife spanbeforetheyexfoliatedtobereplacedbythepermanentteeth Thisusuallyoccursbetweentheagesof6and13years Thedeciduousincisorsandcanineshavepermanentsuccessorbutthefirstandseconddeciduousmolarsarereplacedbythefirstandsecondpremolarsrespectively ThedeciduousdentitioncomprisesfewerteeththanthepermanentdentitionwithatotalofTENmaxillaryandTENmandibularteeth GENERALCHARACTERISTICS Thedeciduousteethgenerallyhaveseveralimportantdifferencesinmorphology composition sizecolouraslistedbelow 1 Thedeciduousteetharesmallerthanthepermanentteeth PRINCIPALDIFFERENCESBETWEENDECIDUOUSANDPERMANENTTEETH PRINCIPALDIFFERENCESBETWEENDECIDUOUSANDPERMANENTTEETH 2 Theenamelofthedeciduousteethiswhiterandmoreopaque whichgivesthecrownalightercolourthanthatofthepermanentteeth 3 Theenamelofthedeciduousteethismorepermeableandmoreeasilyworndown Thedegreeofpermeabilityislessenedafterthestartofrootresorption PRINCIPALDIFFERENCESBETWEENDECIDUOUSANDPERMANENTTEETH 4 TheDEPTHOFENAMELismoreconsistentandthinnerthaninthepermanentteeth beingfrom0 5mmto1 00mmthick PRINCIPALDIFFERENCESBETWEENDECIDUOUSTEETHANDPERMANENTTEETH 5 Deciduousteethhaveapronouncedcervicalmargin Theenamelbulges insteadoftaperinggently atthecemento enamljunction whichisstraighterthaninthepermanentteeth Thiscervicalbulgeisaccentuatedinthemesiobuccalareaofdeciduousmolars PRINCIPALDIFFERENCESBETWEENDECIDUOUSANDPERMANENTTEETH 6 Innewlyerupteddeciduousteeth thecuspstendtobemorepointed PRINCIPALDIFFERENCESBETWEENDECIDUOUSANDPERMANENTTEETH 7 Therootsofthedeciduousteethareshorter lessstrongandlighterincolourthanthoseofthepermanentteeth PRINCIPALDIFFERENCESBETWEENDECIDUOUSANDPERMANENTTEETH 8 Therootsofanteriordeciduousteetharelongerinproportiontothecrown Therootsofposteriorteetharemoredivergenttoallowforthedevelopingpermanentsuccessor Theyflareoutfromeachotherwiderthanthecrownmeasurement andformaminimalcommonroottrunk PRINCIPALDIFFERENCESBETWEENDECIDUOUSANDPERMANENTTEETH 9 Thepulpchambersarelargerthaninthepermanentteethandfollowtheexteriormorphologyofthetoothmoreclosely theretends thereforetobelessdepthofdentine PRINCIPALDIFFERENCESBETWEENDECIDUOUSANDPERMANENTTEETH 10 Therootcanalofdeciduousteethareveryfine PRINCIPALDIFFERENCESBETWEENDECIDUOUSANDPERMANENTTEETH 11 Usuallytherearenodepressionsorperikymataonthelabialsurfaceofthecrownoftheincisors Thesesurfacesaresmooth ONTHEANTERIORTEETH ONTHEANTERIORTEETH 12 Therearenomamelonesontheincisaledges 13 Thecervicalridgeonthefacialsurfacesisprominent ONTHEANTERIORTEETH 15 Therootisnarrowmesiodistally ONTHEANTERIORTEETH 14 Thecingulaeareprominentorseemtobulgeandoccupyaboutonethirdofthecervicoincisallengthlingually ONTHEPOSTERIORTEETH 16 Themolarcrownhaveanarrowchewing occlusaltable buccolingually 17 Themolarsoccluosalsurfacesareshallow Inotherwords thecuspsareshort theridgesarenotpronounced andthegroovesarecorrespondinglynotasdeep ONTHEPOSTERIORTEETH 18 Themolarcrownsarewidemesiodistally yetveryshortcervico occlusally 19 Thebuccalcuspsofmolarsarenotpointedorsharp withcuspslopesmeetingataverywideobtuseangle 20 Therearefewgroovesordepressionsinallsurfacesofthecrowns ONTHEPOSTERIORTEETH 21 Thecervicalridgeisprominentmesially itiseasytodistinguishrightsfromleft ONTHEPOSTERIORTEETH 22 Thesecondmolarsarelargerthanthefirstmolars 23 Therootfurcationisnearthecrown andthereislittleifanyroottrunk ONTHEPOSTERIORTEETH ONTHEPOSTERIORTEETH 24 Therootsarewidelyspreadbeyondtheconfinesofthecrowntoallowforthedevelopingpermanentsuccessors ONTHEPOSTERIORTEETH ONTHEPOSTERIORTEETH ONTHEPOSTERIORTEETH 25 Rootsarethinorslender ONTHEPOSTERIORTEETH ONTHEPOSTERIORTEETH 26 Thesecondmolarrootsarespreadmorewidelythanthefirstdeciduousmolar oppositeofthepermanentmolars E D 6 7 IMPORTANTFUNCTIONSOFSOUNDDECIDUOUSTEETH Maintenanceofanormalappearance FormulationEfficientmasticationoffood ofclearspeech Maintenanceofaproperdiet Missingorbadlydecayedteethmaybeonereasonthatyoungchildrenrejectfoodsthataredifficulttochew IMPORTANTFUNCTIONSOFSOUNDDECIDUOUSTEETH 5 Avoidanceofinfectionandconcomitantpain Anabscessfromadeciduoustoothcancausedarkspots Turner sspots onthepermanenttoothdevelopingbeneathit 6 Maintenanceofspaceandarchcontinuityfortheemergenceofpermanentteeth Chronology Initialcalcification3 4monthsinuteroCompletionofcrown4monthsEruption7 monthsCompletionofroot1 years MAXILLARYFIRST CENTRAL DECIDUOUSINCISOR MAXILLARYFIRST CENTRAL DECIDUOUSINCISOR PRINCIPALIDENTIFYINGFEATURES 1 Roundeddisto incisalangle sharpmesio incisalangle 2 Similartomaxillaryfirstpermanentincisorbutsmallerandchubbieroverall 3 Largelingualcingulumandpronouncedbulgeonlabialsurface MAXILLARYFIRST CENTRAL DECIDUOUSINCISOR M D M D PRINCIPALIDENTIFYINGFEATURES 4 Roottiltsdistallyandlabiallyfromlongaxisofcrown 5 Onerootcanal twopulphorns onemesial onedistal Mesialhornslightlylarger VARIATIONSNonoticeablevariations MAXILLARYFIRST CENTRAL DECIDUOUSINCISOR MAXILLARYSECOND LATERAL DECIDUOUSINCISOR Chronology Initialcalcification4 monthsinuteroCompletionofcrown5monthsEruption8 9monthsCompletionofroot1 2years MAXILLARYSECOND LATERAL DECIDUOUSINCISOR MAXILLARYSECOND LATERAL DECIDUOUSINCISOR Chronology Initialcalcification4 monthsinuteroCompletionofcrown5monthsEruption8 9monthsCompletionofroot1 2years Chronology Initialcalcification4 monthsinuteroCompletionofcrown5monthsEruption8 9monthsCompletionofroot1 2years MAXILLARYSECOND LATERAL DECIDUOUSINCISOR PRINCIPALIDENTIFYINGFEATURES 1 Similarshapetomaxillarydeciduouscentralincisorbutcrownissmallerandnarrowerinproportion 2 Lingualcingulumlesspronounced MAXILLARYSECOND LATERAL DECIDUOUSINCISOR 3 Roundeddisto incisalangle sharpmesio incisalangle 4 Onerootcanal twopulphorns onemesial onedistal Mesialhornslightlylarger VARIATIONSRare incontrasttothehighlyvariablemaxillarypermanent PRINCIPALIDENTIFYINGFEATURES MANDIBULARFIRST CENTRAL DECIDUOUSINCISOR Chronology Initialcalcification4 monthsinuteroCompletionofcrown4monthsEruption61 2monthsCompletionofroot1 2years PRINCIPALIDENTIFYINGFEATURES 1 Singletaperedrootmoreroundedthanthatoflowermandibularpermanentincisor tendstoinclinedistally 2 Smallestoothinthedeciduousdentition 3 Sometimesalogitudinalgrooveonthedistalsurfaceofroot 4 cervicalmarginmostsinuousonmesialside MANDIBULARFIRST CENTRAL DECIDUOUSINCISOR MANDIBULARFIRST CENTRAL DECIDUOUSINCISOR PRINCIPALIDENTIFYINGFEATURES 5 Large convexcingulumandpronouncedbulgeonlabialsurface 6 Onerootcanal twopulphorns onemesial onedistal VARIATIONS Thepronouncedcervicalbulgeonthelabialsurfacemaybereducedorcompletelyabsent MANDIBULARSECOND LATERAL DECIDUOUSINCISOR MANDIBULARSECOND LATERAL DECIDUOUSINCISOR Chronology Initialcalcification4 monthsinuteroCompletionofcrown41 2monthsEruption7monthsCompletionofroot1 2years Chronology Initialcalcification4 monthsinuteroCompletionofcrownEruption PRINCIPALIDENTIFYINGFEATURES 1 Singletaperedrootwithroundcross section tendtoinclinedistally 2 Roundeddisto incisalangle sharpmesio incisalangle MANDIBULARSECOND LATERAL DECIDUOUSINCISOR MANDIBULARSECOND LATERAL DECIDUOUSINCISOR 3 Incisiveedgeslopesdownwardsfrommesialtoslightlylowerdistalsurface 4 Crownmay insomecases showtwistingonrootforincisiveedgetofollowmandibulararch PRINCIPALIDENTIFYINGFEATURES MANDIBULARSECOND LATERAL DECIDUOUSINCISOR PRINCIPALIDENTIFYINGFEATURES 5 Largerthanlowerfirst central deciduousincisor 6 Lingualsurfacemaybemoreconcavethanthatofthemadibularcentraldeciduousincisor 7 Singleroot twopulphorns onemesial onedistal VARIATIONSNonoticeablevariations Afeatureofthedeciduousdentitionisitsconsistencyinitsmorphology MAXILLARYDECIDUOUSCANINE Chronology Initialcalcification5monthsinuteroCompletionofcrown9monthsEruption16 20monthsCompletionofroot3years MAXILLARYDECIDUOUSCANINE PRINCIPALIDENTIFYING1 Mesialslopeofcusplongerthandistalslope 2 Conicalcrownwithpronouncedcervicalbulgeandpointedcusp MAXILLARYDECIDUOUSCANINE MAXILLARYDECIDUOUSCANINE MAXILLARYDECIDUOUSCANINE MAXILLARYDECIDUOUSCANINE MAXILLARYDECIDUOUSCANINE MAXILLARYDECIDUOUSCANINE MAXILLARYDECIDUOUSCANINE MAXILLARYDECIDUOUSCANINE M D FEATURES D M MAXILLARYDECIDUOUSCANINE PRINCIPALIDENTIFYINGFEATURES3 Labialandlinguallogitudinalridgesextendingfromcusptips 4 Crownmorebulbousthanthatofmaxillarypermanentcanine MAXILLARYDECIDUOUSCANINE PRINCIPALIDENTIFYINGFEATURES 5 Diamond shapeoutlineroundedcornersfromincisalaspect 6 Cervicalmarginrisesfurtherincisallyonthemesialthanonthedistalsurface D M PRINCIPALIDENTIFYIN7 Singlerootoftenmorethantwicethelengthofthecrown Slendertaperwithsimilarcross sectiontothatofthemaxillarypermanentcanine distallyinclined 8 Singlerootcanal pulpchamberelongatedanddirectedtowardscusp VARIATIONSAsymmetricalandsymmetricalcrownformsareequallycommon Otherwisenonoticeablevariations MAXILLARYDECIDUOUSCANINE FEATURES MANDIBULARDECIDUOUSCANINE MANDIBULARDECIDUOUSCANINE Chronology Initialcalcification5monthsinuteroCompletionofcrown9monthsEruption16 20monthsCompletionofroot2 3years PRINCIPALIDENTIFYINGFEATURS 1 SmallerandslimmeroverallthanthemaxillarydeciduousCanine 2 Lesswell definedlabialandlinguallongitudenallyridges lingualridgeoftencompletelyabsent 3 Concavelingualsurface 4 Distalslopelongerthanmesial 5 Cervicalmarginmoresinuousonmesialside 6 Singletaperingrootinclinesdistallyandslightlylabially 7 Singlerootcanal pulpchamberelongatedanddirectedtowardscusp VARIATIONS Nonoticeablevariations Linguallogitudenalridgeoccasionallypresentonlingualsurface MANDIBULARDECIDUOUSCANINE PRINCIPALIDENTIFYINGFEATURS 1 SmallerandslimmeroverallthanthemaxillarydeciduousCanine 2 Lesswell definedlabialandlinguallongitudenallyridges lingualridgeoftencompletelyabsent 3 Concavelingualsurface 4 Distalslopelongerthanmesial 5 Cervicalmarginmoresinuousonmesialside 6 Singletaperingrootinclinesdistallyandslightlylabially 7 Singlerootcanal pulpchamberelongatedanddirectedtowardscusp VARIATIONS Nonoticeablevariations Linguallogitudenalridgeoccasionallypresentonlingualsurface MAXILLARYFIRSTDECIDUOUSMOLAR Chronology Initialcalcification5monthsinuteroCompletionofcrown6monthsEruption12 16monthsCompletionofroot2 2 years PRINCIPALIDENTIFYINGFEATURES 1 Pronouncedbulgeonmesialsideofbuccalsurface molartubercleofZuckerkandl 2 Trapezoidcoronaloutlinewithnarrowocclusalsurfacerunningmesiodistally MAXILLARYFIRSTDECIDUOUSMOLAR MAXILLARYFIRSTDECIDUOUSMOLAR MAXILLARYFIRSTDECIDUOUSMOLAR PRINCIPALIDENTIFYINGFEATURES 3 Lingualsurfaceshorter mesiodistally thanthebuccal 4 Mesiolingualcusplargestandpointed 5 Widestlabiolingualcrownmeasurementatmesialend MAXILLARYFIRSTDECIDUOUSMOLAR PRINCIPALIDENTIFYINGFEATURES 6 Threerootcanals fourpulphorns mesiobuccal distolingual distobuccalandmesiolingual VARIATIONS Palatalanddistobucclrootssometimesfuse Mesiobuccalcuspsometimeshasanaccessorycuspmesialtoit Distolingualcuspsometimesabsent Zuckerkandl tubercleisoccasionallyscarcelydiscernible MAXILLARYFIRSTDECIDUOUSMOLAR MAXILLARYSECONDDECIDUOUSMOLAR Chronology Initialcalcification6monthsinuteroCompletionofcrown10 12monthsEruption1 2 yearsCompletionofroot3years PRINCIPALIDENTIFYINGFEATURES 1 Morphologyofmaxillaryfirstpermanentmolarduplicatedonasmallerscale 2 Moreprominentbulgeoncervicalpartofbuccalsurface MAXILLARYSECONDDECIDUOUSMOLAR D D L L M M B B PRINCIPALIDENTIFYINGFEATURES 3 Rootshavewiderdivergencethanthoseofmaxillaryfirstpermanentmolar 4 CuspofCarabellipresentinmostcases MAXILLARYSECONDDECIDUOUSMOLAR MAXILLARYSECONDDECIDUOUSMOLAR PRINCIPALIDENTIFYINGFEATURES 5 Threerootcanals threepulphorns mesiolingual distobuccalanddistolingual VARIATIONS CuspofCarabellimaybeabsent Veryrarelythedistolingualcuspmaybesoreducedastobescarcelydiscernible Thepalatalanddistobuccalrootsmaysometimesbefused MANDIBULARFIRSTDECIDUOUSMOLAR MANDIBULARFIRSTDECIDUOUSMOLAR MANDIBULARFIRSTDECIDUOUSMOLAR Chronology Initialcalcification5monthsinuteroCompletionofcrown6monthsEruption12 16monthsCompletionofroot2 2 years PRINCIPALIDENTIFYINGFEATURES 1 MolartubercleofZuckerkandl anexaggeratedcervicalbulgeonthebuccalsurfaceofthecrownoverthemesialroot withaconsiderablecervicalconstriction 2 Fourcusps buccalcuspscompressedlabiolinguallywithnoclearseparationbetweenthemincontrasttothetwolingualcuspswhichareclearlydefinedandroughlyconicalinshape 3 Mesiolingualcusplargest MANDIBULARFIRSTDECIDUOUSMOLAR MANDIBULARFIRSTDECIDUOUSMOLAR MANDIBULARFIRSTDECIDUOUSMOLAR MANDIBULARFIRSTDECIDUOUSMOLAR MANDIBULARFIRSTDECIDUOUSMOLAR L B D M PRINCIPALIDENTIFYINGFEATURES 4 Tooth