最新国外口腔解剖乳牙.课件-药学医学精品资料.ppt

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1、最新国外口腔解剖乳牙.课件-药学医学精品资料INTRODUCTIONTheworddeciduouscomesfromaLatinwordmeaningtofalloff.Deciduousteethfallofforareshedlikeleavesfromadeciduoustree.GENERALCHARACTERISTICSThedeciduousteethgenerallyhaveseveralimportantdifferencesinmorphology,composition,sizecolouraslistedbelow:1-Thedecidu

2、ousteetharesmallerthanthepermanentteeth.PRINCIPALDIFFERENCESBETWEENDECIDUOUSANDPERMANENTTEETHPRINCIPALDIFFERENCESBETWEENDECIDUOUSANDPERMANENTTEETH2-Theenamelofthedeciduousteethiswhiterandmoreopaque,whichgivesthecrownalightercolourthanthatofthepermanentteeth.3-Theenamelofthedeciduoust

3、eethismorepermeableandmoreeasilyworndown.Thedegreeofpermeabilityislessenedafterthestartofrootresorption.PRINCIPALDIFFERENCESBETWEENDECIDUOUSANDPERMANENTTEETH4-TheDEPTHOFENAMELismoreconsistentandthinnerthaninthepermanentteeth,beingfrom0.5mmto1.00mmthick.PRINCIPALDIFFERENCESBETWEENDECI

4、DUOUSTEETHANDPERMANENTTEETH5-Deciduousteethhaveapronouncedcervicalmargin.Theenamelbulges,insteadoftaperinggently,atthecemento-enamljunction,whichisstraighterthaninthepermanentteeth.Thiscervicalbulgeisaccentuatedinthemesiobuccalareaofdeciduousmolars.PRINCIPALDIFFERENCESBETWEENDECIDUOU

5、SANDPERMANENTTEETH6-Innewlyerupteddeciduousteeth,thecuspstendtobemorepointed.PRINCIPALDIFFERENCESBETWEENDECIDUOUSANDPERMANENTTEETH7-Therootsofthedeciduousteethareshorter,lessstrongandlighterincolourthanthoseofthepermanentteeth.PRINCIPALDIFFERENCESBETWEENDECIDUOUSANDPERMANENTTEETH8-Th

6、erootsofanteriordeciduousteetharelongerinproportiontothecrown.Therootsofposteriorteetharemoredivergenttoallowforthedevelopingpermanentsuccessor.Theyflareoutfromeachotherwiderthanthecrownmeasurement,andformaminimalcommonroottrunk.PRINCIPALDIFFERENCESBETWEENDECIDUOUSANDPERMANENTTEETH9-

7、Thepulpchambersarelargerthaninthepermanentteethandfollowtheexteriormorphologyofthetoothmoreclosely,theretends,thereforetobelessdepthofdentine.PRINCIPALDIFFERENCESBETWEENDECIDUOUSANDPERMANENTTEETH10-Therootcanalofdeciduousteethareveryfine.PRINCIPALDIFFERENCESBETWEENDECIDUOUSANDPERMANE

8、NTTEETH11-Us