Odontology PDF - Human Dentition

ODONTOLOGY! 1. Description of human dentition. Definition and main parts of the teeth. Humandentition is Diphyodont meaning we have two different set of teeth through our lifetime Desiduous Primary teeth and Permanent secondary teeth Humandentition is also Het...

ODONTOLOGY! 1. Description of human dentition. Definition and main parts of the teeth. Humandentition is Diphyodont meaning we have two different set of teeth through our lifetime Desiduous Primary teeth and Permanent secondary teeth Humandentition is also Heterodont meaning it containsdifferent teeth incisors Canines Premolars and Molars These teethdiffer in shape and properties in same arch Primaryteeth are 20 15 in eachquadrant Primary molars : non-succid 1 centralincisor I don't replace anything) 1 Lateral incisor iz Cn Mz 1 Canine 2 Molar Permanent teeth are 3218in eachquadrant 1 Central incisor 1 Lateral incisor 1 Canine 1219 P2 Ms 2Premolars 3 Molars Anteriorteeth Incisors and Canines Posteriorteeth Premolars and Molars Permanent teeth start to erupt at byandkeeperupting till 17 21y Dentalarches Upperarch Maxillary staysstationaryI Lowerarch Mandibolarmoveable Quadrants UpperRight UpperLeft LowerRight Lower Left Shapeofarches Primaryarches are SEMICIRCULAR Permanent arches are SEMIELIPTICALsupper PARABOLICflower Occlusion mandibularandmaxillaryarches are incontact Upperarch is largerthan lower arch Upperteeth usually surround lowerteeth in normal occlusion Eachtooth is an independentorgan Belongs to masticatory mechanism is found in oralcavity 3 main roles mastication speach phonetics aestethiis Toothhas two mainparts Crown andRootseparatedby cervical Line cervicalline cemento EnamelJunction Parts oftooth Hardtissue Alveolarbone cementum softtissue Gingiva Periodontalligament PDL AnatomicalCrown Partoftoothcovered enamel by clinicalcrownPartoftooththatisvisibleinoralcavity abovegumline AnatomicalRootPartofrootcoveredwithcementum clinicalRootPartofrootlocatedinjaw oblasts Enamel Hard tissue covering crown Camel Dentine Hard tissue under enamelcrownlodontoblasts it is softer than enamel cementum Layerof calcification tissuecoveringroot softer than dentine Pulpchamber cavitywhere pulp is located Pulp Central hollow chamber oftooth containingdelicate connective tissue Inerves blood lymphvessels Lined peripherally byodontoblasts Root canal Contains part of pulpchamber Gingivagum surrounding tooth Periodontium surrounding tissues oftooth provide support for tooth surface of teeth Vestibular LabialAnterior Burial Posterior  al Lagu Palatal upperjaw proximal Mesial closeto midline interproximalSurface Distal Awayfrommidline in between Bitingsurface incisal Anterior OcclusalPosterior 2. Digit notations. n total thereare 3 differentnotationsystem 1 Zigmondy Palmer Notation Usedin UK 2 Universal System 2digitnumbering 11 32 A T 3 FDI FederationDenature International system 12digitnumbering mostimportant Used sodental offices staffinsurancecompanies can better communicate between each other regarding exact details of certain teeth Zigmondy Palmer Notation dolfZigmondydeveloped the idea in 1861 O e derided teeth into 4quadrants and each tooth was given sign according to its location in mouth maxillary right Lmaxillaryleft its mandibular rightMandibularleft me teethin eachquadrant arenumberedfrom 1 8 forpermanent entition and roman numeral I V for deciduous dentition oman numbers were changed Inot computerfriendly to letter E fordeciduous dentition I oman numerals used in Zsigmondy system - -L enters in Palmer 51271 & 76 5 4 3 21 1 2 34 5678 E DC B A A BC DE 7654321 1 2 34 5678 E DC B A A BC DE Universal System sermanent secondary Dentition Number 1 32.......... Trinary Dentition Letters A T FDI system This systemis used in University Clinics quadrant It is the two digit numbering Thefirstdigit representsquadrantnumber Thesecond represents toothnumber oth - to Thelettersystem I spin i inf 03 0201 0102 03 sup dext sin Indexwithineachtoothgroup Psupsin upperleftfirst premolar 3. Losses of tooth hard tissue. Threetypes of processes result in loss of tooth substances trauma 1 Attrition 2 Abrasion Abfraction 3 Erosion normal Attrition Slit Is the wearingaway oftooth structure as physiological result of tooth toothcontact and by friction offood And* tooth grindingduring stress or sleep bruxismpathological * Affects Occlusalsurfaces primarily andproximalsurfaces - mesial of teeth Affectedsurfaces most commonly seen on palatal surface Tupper and vestibularsurface lower 5grades of attrition 1 Loss of tooth material localised in enamel - 2 Dentin is exposed on tips ofcusps and incisal - edges 3 Dentin exposed on whole occlusal surface enamel - surrounds it 4 The processreaches pulpchamberand pulp can - become inflamed 5 Tooth worn down to gingival margin gumtissue aggressive Abrasion neck surface Is the wearingaway oftooth by- mechanical processes other than mastication and tooth tooth content Causes excessive or improper tooth brushing hard flossing or use tooth picks can also be causedbyworking in pollutedimengadl area Causes sensitivity in teeth due to exposed dentine or thinning of enamel buccal surface * Neck area is worn away Painful Producesdeep U or V shapeddepressionstowards cervicalsurface neck thinner - of crown Exposureof underlyingdentine and causingincreased  y Firstsign shiny flat area on occlusal surface Erosion - Wearing away of non occluding surfaces of teeth by chemical dissolution mainlyacid Reduction in saliva increases erosion cuz it has antibacterial properties and is a natural buffer intrinsicoriginofacid regurgitationcuppkostofgastricacid habitualvomiting buliemia GERD area- Affected palatalandocclusalmainly Extrinsicoriginofacid Dietjuices areaO Affected incisorsonincisalsurface in environment 3 Soda firePfough working Causes Dietary juice Medical Hel replacement Vitamin C Aspirin Gastric reflux 4. Description of tooth identifiers. Mühlreiter characteristics. crown 1 Angular characteristics Distoincisal line angles are more rounded than mesioincisal angle IU L D 2 Cervical line curvature curves differently on mesial and distal surfaces of tooth to buccal and lingual surfaces curvature line more pointed on mesial than of distal aspect 3 Arch characteristics Curvature of mesio vestibular crown surface is more sharply curved than disto vestibular 4 Cervical Contour Characteristic The level of cervical line the contour of mesial part the tooth is FLAT but distal is curved 5 characteristic Cusp inclination Longitudal axis of mandibular posterior teethincline lingually Axis of maxillary teeth is almostventricallyoriented Neck root 1 Root inclination in vestibularplane Root inclines distally From facialaspect axis ofroot and axis of crown intersect each other at level ofcervical line The angle formed bytwo lines opens distally 2 Root inclination in saggital plane There is an angle between crown and root Root bends lingually and is in different direction to crown edge 3 Curvature of apical root Apical third of root tends to curve toward distal direction 4 Difference between mesial and distal root The distal surface oftooth has a groovedeeper than mesial groove 5. The morphology of the maxilla. and maxillary teeth he part of face between orbit two maxillae form upperjaw Maxilla s a complex pyramidal shaped bone not a solid bone contains air cavity Largest air cavity maxillary air sinus lHighmorecavity Each maxilla has body and 4 processes Frontal process upper vertical extension  Zygomaticprocess sideextension Alveolar process Lower extension Palatine process Horizontal extension hermaxillary suture between two maxillae Four surfaces medial nasall Superior orbital Posterior finfratemporall Anterior facial 3 main cavities of face orbital cavity Nasal cavity Mouth superiorly each maxillae contribute to inferior and medial rims of orbit Laterally right and left side zygomatic process of each maxillae articulates with zygomatic bone and medial frontalprocess each maxillae articulates with frontal bone Laterally to opening of nasal cavity is bodyof maxilla on anterior surface of body of maxilla Just below inferior rim of orbit is the infra orbital foramen inferiorly each maxilla ends as alveolar process contain teeth and forms upperjaw n alveolar process of maxilla palatine there are tooth sockets alveolus n teralveolar septum thin plates of bones saperating alveoli ofteeth nterradicular septum between roots mesial root and distal  pl e Hard palate maxilla Hard palate palatinebone 6. The morphology of the mandible. Three main parts Ramus Posterior Body Anterior Angle in between sensitive Mandible is the mostinferior structure of skull Jodyanteriorly meet at an angle Ramusposteriorly Mandible is arbitrarily divided into two Lower part is baseof mandible 11 Upperpart is alveolarpart ofmandible12 1 symphysis fusionconnection midline of base of mandible 2 Contains teeth Alveolus dental sockets Has a midline swelling mental protuberance on anterior surface where two sides come together Lateral to mental protuberance on either side areslightly more pronounced bump mental tubercles Laterally a mental foramenfunder 2nd premolar continuing past this foramenis aridge obliquelinel passing from frontof ramus onto body mandible of Nerves inside mandible exit from mental foramen Gives nerve supply to lower teeth Oblique line strong bony line fromfront of ramus to body Head on mandible Condyle caput mandiblae Partof jawjoint collum mandible  I Ramus has 3 upperparts with 2 body extensions coronoid process anterior and between them is a mandibular Condyloid process posterior notch On the inside of mandible we have mylohyoid groove below mandibularforamen Its a linear groove Where muscle is attached to bone surface mandibular foramen entering hole for nerve of lowerteeth Lingala little lounge shaped bonyelement where patientsinject Temporomandibular joint Lateral surfaceof ramus Tuberositas pterygoidea Area ofroughness wherefibers attach muscle inserting on bone surface in inner part we have 2 depression and 2 salivaryglands Sublingual fossa upperdepression sublingual salivary gland Submandibular fossa lower depression submandibular salivarygland secondlargesgland Largest salivary gland is Parotid gland D Xray orradiologymethodcalleddentalcomputed tomography investigates anddepictsfacial Keleton upperand lowerjaws teethinside and even soft tissues 7. Development of the crown. Tooth germ bud is aggregationof cells Tooth bad composed of 3parts 1 Enamel organ 2 Dental papilla 3 Dental follicle 1 Enamel organ composed of outer enamel epithelium inner epithelial epithelium stellate reticulum and stratum - intermedium - These cells give rise to ameloblasts which produce enamel The growth of cervical loop where cells into deeper tissues form Hertwig's epithelial root sheath Determines shape of root 2 Dental papilla contains cells that develop into odontoblasts dentine Mesenchymal cells within dental papilla responsible for formation of pulp 3 Dental follicle gives rise to cementoblasts osteoblasts and fibroblasts Cemento blasts cementum supporting Osteoblasts Alveolar bone around roots structures Fibroblasts Periodontal ligament Developing of tooth bud takes place around 7th The first step in tooth formation week of embryonic life That is when we can distinguish vestibular lamina and dental lamina from each other bud to The dental lamina connects developing tooth epithelial layer of mouth Tooth development has 4 main stages 1 Bud stage 2 Cap stage 3 Bell stage 4 Crown stage Bud Stage Appearance of tooth bud without clear arrangement of sells when epithelial cells proliferate rapidly stage begins into mesenchyme of jaw bud Primary epithelial cells thicken into a shaped V vestibular and dental lamina cells proliferate as two separate buds The surrounding mesenchymal cells proliferate which results in their condensation in two area dental papilla and dental follicle Cap Stage Arrangement of cells in tooth bud Unequal growth in different parts of tooth bud leads to sap stage n crease in mitotic activity like a lap over Because enamel organ sits called  I P i enamelorgan looks Lik Bell Stage a cap Histo differentiation is divided into two steps early beforedentine formation late advanced bell stage after formation of and first layer of dentine Earlybellstage Continued growth of tooth germ Enamel organ comes to resemble a bell cells of enamel organ deride into 4 layers 1 Inner enamel epithelium columnar layerI z 2 Outer enamel epithelium cuboidal layer J 3 Stellate cells 4 Intermediate cells Cervicalloop Inner and outer epithelium grow and form Inner dental enamel differentiates to form ameloblasts Fibers blood vessels and nervesappear in dentalpapilla formspulp Ieffmtenbamiti 1d.is aaemines enamelepithelium cells stopswhere cuspsform Enamel knot Mitosisof inner sells change in shapefromcuboidal to columnar inner enamel epithelium closer to stratum intermedium Nuclei inner enamel epithelium cells move of and away from dental papilla Adjacent layerofcells in dentalpapillaincrease in size and differentiate into odontoblast dentin forming cell cell of inner enamel epithelium secrete an organic After dentin formation begins matrix in dentine Matrix immediatelymineralises andformsenamel Ameloblasts continue the process ofenamel formation addingenameltooutersurface oftooth change in dental papilla and are during bell stage blood capillaries appear indicative ofmetabolicactivity Eventually results in dentine formation Nerves to but nerve supply of pulp and dentin s P de Rootsheathof Hertwig before birth Determinesrootform Retainstubularformwh itderidesintoroots Successional Lamina another lamina from which permanent teeth start to develop Serressells Remnants of dental lamina Airi rallyimportant wheninflamatio 8. Development of root and formation of the periodontium. Starts afterdetermination ofcrown nner and outerepithelial cells elongate andformcervicalloop root sheath of Hertwig Zoot sheath determines root form subdividesformultipleroots Dental follicle differentiates to form 1 Fibroblasts PDL Middlelayer 2 Osteoblasts Alveolarbone Outer layer 3 Cementblasts cementum Inner layer eripheral cells of dentalpapilladifferentiate toform odontoblasts to make dentine After sheath ofHertwigbreaksdown the three cell types start to secrete when cusps appear in oral cavity approximatelyHalfof Root is formed Dh will change until bone reaches its final size and tooth will find place its n jaw bone Cementum tard tissue Alveolar periodontium Soft tissue Gingiva PDL sharpeyfibers partsof PDLfibers embedded in cementum on one side and embedded in alveolar bone on the other LaminImpatadjaient cellular to PDL it is Costeocytes 9. Phase of the tooth eruption. Developmental dates of deciduous and permanent teeth. of teeth within and throughalveolar bone of Eruption movementlower upper or and jaw mucosa to reach oral overlying oral cavity There are 3phases  up 2 Pre functional phaselemerganie phase 3 Functionaleruptive phase post eruptive phase Teeth erupt at maximal rate to reach occlusalcontact and then they continue to erupt at slower rate to compensate for growth and occlusal wear Eruption of tooth is aftercompletionof crown Tooth development starts with mineralisation of enamel and ends with formation of apical foramen Pre eruptivephase Movement of developingand growing tooth germs within alveolar process before tooth formation Growing teeth move in manydirection to keep theirposition in expending jaw Bodily movement shift of toothgerm Eccentric growth partof toothgrowths andpartdoesn't Thisphase is before root formation starts 2 Pre functionalphase starts with initiation of root formation Ends with teeth reaching occlusal contact 5 major events 1 Secretory phase of amelogenesis completed 2 Intraosseousstage root formation begins bone ofcrypts 3 Supraosseousstage when eruptivetooth moves occlusallythrough and connective tissue of oral mucosa 4 Clinical eruption Tip of crown enters oral cavity 1 2 213ofrootformed 5 Activeeruption Eruptingtoothcontinues to move occursally at maximum rate 3 Functionaleruptive phase Begins when teeth reach occlusion continues as long as teeth are in oral cavity Alveolar process alveolar bone increases in neigh and density Teeth continue to move occlusally  Root continues to grow Later in life attrition may wear down occlusalsurface Mesial drift of teeth As occlusion established Principle fibers of PDL are establishedinto groups Sharpyfibers in 450 stronger Nerves develop from apex togingival Factors that affect tooth eruption vasodialation blood vessels become bigger increaseeruption Hyperemia excess ofblood in area Permanent teeth need 2 3y to finish root formation Primaryteeth need 1,5g to finish root formation 1 Larger cementum in older people on appisal tips i Permanent 6 18years Mixed G 12years rimaryteeth softttionchftetion mandible coffYtioncormopolition maxilla centralincisor 7,5m 1,5m 1,59 6,5m 2,5m 159 Lateral incisor 8m 2,5m 24 7m 3m 1,5g am 3Yay canine 16 20m 16 20m am 3449 12 16m Gm 2,5g 1st Molar 12 16m 5,5m 2449 2nd Molar 20 30m 11m 3D 10m BY 20 30m Permanent teetheruptslightlyearlier in girls Mandibular teeth usuallyerupt earlier than maxilla sermanent teeth coffetioncormftetion coffYtioncompletion maxilla Centralincisor 7 8y 4 59 109 maggble 4 by ay Lateral incisor 4 Sy 119 7 4 Sy toy 8 ay 13159 8y 12My canine in b Fy 9 toy b Fy 1st Premolar Ry 5 by 12 By 10 12g 5 by 12 By lo ily 2nd Premolar b Fy 12149 13 lo Ry it Ry G Fy My 1st Molar b 9 109 9 104  y y Y 2nd Molar 12 By 7 8y 14 1by 11 13y 7 8y M 159 3rd Molar 17 21y 12 1by 1825g 172ly 12 16y 18 259 Mandibular teeth usuallyerupt earlier than maxillary In maxilla 1st Premolars eruptbeforecanines Both jawsfirst molars beforecanines First molar is usually first permanent tooth erupt Exfoliation roots ofbbyteeth resorbedanddisolved Resorption Osteoclasts bonedestroyingcells congenitallymissing forth neverformed Edentulous No teeth present 10. Differentiation of permanent Maxillary central incisors 11,217 Root 1 100 RootCanal 1 PulpHorns 3 Eruption 7 8 y Cervical line more curvedon mesial side Crown and root equallength nice Root inclines distally Root triangleshaped 3 mammelons but worn out byattrition Mesioincisal angle acute but distoincisal more rounded Showel shaped crown Labial surface is smooth but sometimes shallowgrooves and is convex Palatal surface concave exept cingulum convex Largest incisor mesial mesial contact with other incisor Maxillary Lateral Incisor 12,22 Root 11 Root Canal 1 100 Horns 7 3 Pulp L up y Crown shorter than root Root inclines distally and palatally Cross section of root canal Oval Mesioincisal angle is acute Distoincisal morerounded Labial surface more convex than central Palatal surface more concave than central Cingulum not as well developed as central Shallow vertical groove distally Foramen cecum can be present More prominent marginal ridgeon lateral Mandibular central incisor 31,41 Root 1 70 one 30 two Root Canal PulpHorns 3 Eruption G Fy Smallest tooth Root inclines distally Root oval shapedin cross section Mestoincisal and Distoincisal angles nearlyidentical 3 mamelons worn away by attritionI Lingualsurfacesmooth Distal groove on root more marked Stright incisal tooth Small cingulum Onlytooth that occluses onlyone tooth Labial surface convex Mandibular Lateral Incisor 32 427 Root T Root Canal 55 one 45 two PulpHorns 3 Eruption 7 891 Mesial side longer than distal producinga slope Mesioincisalangle acute distolingual rounded  3 S Root groove and distal deepersurfase on mesial Distal side of lateral inclines lingually 11. Differentiation of permanent canines. Maxillary Canine 13 23 Root117 Root Canal e Pulp horn 117 Cusp 1 Eruption 17 12y tooth Strongest and longest All surfaces are convex approximetlycentrally Largepointed cusp placed Distal slopelonger than mesial Great bulk of dentine yellowish Bulkycingulum Root is almost triangular in cross section Root inclines distally curved palatal direction Deepergroove distally no or shallow mesially Palatally central enamel ridge Palatally two fossas Mandibular canine 133431 Root e Root Canal 170 one 30 two Labialandlingual PulpHorns 1 Cusps 1 Eruption 9 10 y Smaller and shorter than maxillary Single cusp not as pointed as in maxillary and less well developed  g g g Crown tilts distally since mesial surface is a straight line Well marked cingulum on lingual surface and central enamel ridge and 2 fossa Labial surface curved Ventrical mesial and distal grooves may be present on root Incisal cervisally longer crown than maxillary Only canine that is capable of bifurcated root ifeng.IEiiYan Mandibular gamanaima n crown is narrower mesiodistally Mandibular cusp is less pointed Cingulum on maxillary larger and centered mesiodistally Mandibular cingulum slightly to distal 12. Description of maxillary premolars. Maxillary 1st Premolar114 24 Root 2 buccal and palatal Root canal 2 one on each root Pulp horns 2 burial and palatal Cusps 2 sharplydefined lo 11 y Eruption Concave canine fossa on mesial surface of crown extending to pronounced longditudal groove on mesial surface of root Mesial surface of buccalcusplonger than distal Pulp tilts slightly mesially Occlusal outline more angular than maxillary 2nd premolar Crown has pentagonal shape Occlusal surface is  g central groove mesio distally Two triangular fossa Palatalcusp tips is shiftedmesially Asthetic and grindingfunction Mesial marginalridgegroove No marginalridgegroove distally Buccal cusp larger than palatal Eggshaped Maxillary 2nd Premolars 15,251 Root 1 flattenedmesiodistally curves distally Root Canal 11 PulpHorns 2 Cusps 2 nearlyequal in size burial larger Eruption lo 12 y No canine fossa Oval occlusal outline Mesial slope of buccalcusp shorter than distal slope Grooves form letter it on occlusal surface Has mesial and distal marginalridges Distal groove more distinguished Main groove on occlusal surface longer Nearly equal sized cusps buccal and palata DBridge MB ridge M and D marginal ridges are uninterrupt Differencebetweenmaxillaryistand2ndPremolars P divided root but Pz have 1 root Buccal cusp more pointed on P Distancebetween two cusps maybe greater in difference in Py  13. Description of mandibular premolars. Mandibular 1st Premolar 134 44 Zoot 11 curved distally Zoot Canal e up Horns 2 cusps 21 sharplydefined buccal larger 12 Eruption 10 y 2 occlusal fossae distal larger than mesial Buccal cusp located centrally to apex Lingual inclination of crown to root Buccal surface convex lingual almost straight Circular occlusal outline Grooved on mesiolingual surface Mesial longditudal groove more marked than distal Transverse ridge with central groove on top semismiling Distal buccal ridge bigger than mesial buccal ridge I like canine Mandibular 2nd Premolar 35,45 Zoot 11 curved distally Zoot Canal 11 or 2 up horns 12 or 37 Cusps 2 or 3 burial larger Eruption let 12 y Occlusal outline like square ish rounded Mesial marginalridgehigher than distal No longditudal grooves present cervical cross section Ovoid shaped  gg When 3 B ML DL cusps 3 fossas and centrolingual groove afterimmigmistentnane P lingualcusp is small and non functional as Pz cusp is functional and longer Mesiolingual groove separates mesial marginal ridge on P not Pz 14. Description of permanent maxillary molars. Maxillary 1st Molar 16,26 10 two Root 3 one palatal and two burial 90 three Root canal 3 41 Pulp horns 14 1 cusps 5 fifthone is Carabelli not 100 cusp Eruption167y Largestmaxillarytooth Palatalgroove 3 roots palatal is largest distal smallest trifurcation Centralgrooveover Buccalgroove Mesiobuccal root has 1 2 root canals obliqueridge central fossa Buccal roots curve distally Mesial fossa Romboidalocclusal outline Distalfossa Distolingualfossa Mesiopalatalcusp largest MP MB DB carabelli foramen reacum Distopalatalcuspsmallest Buccalcusp more pointed than Palatal Crown wider buccopalatally than mesiodistalt block letter it pattern grooves on occlusal 2 main fossae Central Distal Oblique ridge between MP and DB Enamelridge Palatal groovesometimesends with foramencaecum Tubercullum Carabelli on palatal side mesially Mesial surface flat and trapezoidal Contact area on occlusal third  Distal marginalridgedips more cerically than mesial Pulpchamber shape similar to crown Roof trunk ca 3mm Palatal outline more convex than buccalCosclusocerically Larger diagonal DP to MB Maxillary 2nd Molar 17,27 Root 13 slight distal inclination Root canal 3 up horns 3 4 Cusps 4 Eruption 12 13y Smaller than 1st molar No carabelli Crown smaller poorlydeveloped Dl cusp 3 cuspids variants possible Heartof triangularshape Transverseridgeinstead ofoblique Rhomboidal occlusal outline Distalcuspsgreatlyreduced in size 3 roots well divergent but not as much as 1st Buccal roots same length closer together coalescence of roots more common than maxillary 1st Maxillary 3rd Molar 118,281 Root 3 short oftenfused and curveddistally Root canal 11 Pulp horns 13 Cusps 13 5 one lingual twobuccal Eruption 17 21 y Triangular occlusal outline Largest cusp mesiopalatal 3cusps MB DB P Crown appears too big for shortfused roots Lots  f ly any g Surgical extraction if stay in bone not withfosets 15. Description of permanent mandibular molars. Mandibular 1st Molar 36 46 Root 2 one distal and one mesial curveddistally Root Canal 3 Pulp Horns 5 cusps 15 threebuccal two lingual Eruption G Fy Largest mandibular tooth Buccal aspect 3 cusps visible Lingualaspect 2 cusps visible Mestobuccal cusp is largest Mesial root is largest of two Ocausally larger mesiobuccaly than buccolingually Crown shorter distally than mesially Crown seems asymmetrical as buccal side longerthan lingual Oblong Cusps MB ML DL DB D Occlusal surface rectangular Occlusal surface has y shapedfissures one lingual two buccal Foramen caecum at end of mesiobuccal groove Dental Caries Sometimes called 6th year molar Central fossa where mesiopalatal cusp ofmaxillary molar occluse Key occlusion Distal outline more convex than mesial flat one Lingual surface flat  Bifurcation groove 8 Burial cervical ridge Mandibular 2nd Molar 37,47 Zoot 2 close together partially fused curveddistally Root Canal 31 4 up Homs Cuspt 4 11 By Eruption Rounded Square occlusal outline Lingual cusps higher than buccal Mesial cusp larger than distal Mesial root larger than distal molar Crown smaller than mandibular 1st than Me Root not as robust but sometimes longer 2 buccal cusps equal height shape on occlusal surface Mandibular 3rd Molar 38 48 Zoot 12 closetogether sometimes fused curveddistally Zoot Canal 3 up Horns 4 Cusps 4 6 Eruption 17 21 y 3rd molar can vary in shape and position usually malformed  All cusps ar short and round Square occlusal outline Marked convex buccal surface inclined lingually Roots often underdeveloped short and thick 16. Morphology of anterior deciduous teeth. Shorter lifespan Replaced by permanent teeth smaller Enamel whiter and opaque Crownlighter More peramble easily worn out Depth of enamel thinner Pronounced cervical margin Enamel bulge Anterior crowns are bulbous with pronounced labial cingulum Newly erupted cusps pointy Roots shorter Pulp chamber larger Root canals fine Maxillarycentralincisor 51 671 Labial crown longer mesio distally  slightly convex labial surface No mamelons Incisal edge is straight vertical development grooves rarelyseen Cervi al bulge Root long in comparison to crown Root curving labially and distally alatal 7 Well developed marginalridges Cingulum is prominent Rootnarrows linguallyfromslightlyflatlabialsurface crosssection fromcervical partof root is triangular shaped esial Distal Bothsurfaces similar wedgeshaped Length labial palatally andcerviso incisally almost similar 11mmdifference curvature of cervical line convexincisally Maxillary Lateralincisor152,62 outlinessimilarto centralincisor it has a smaller crown Mesiodistal lengthshorterthan cervicoincisallength Distalincisal anglemore rounded Root triangular shaped No foramen ceacum Maxillary Canine 53,637 Labial Root shapesimilar to incisors Crown narrowed at neck Mesio distally convex incisal edgehas a welldevelopedcusp Mesialslope ofcusp is longer than distalridge only one B Root is long Palatal Prominentventricalenamelridge centralcingulum seen with mesial anddistalmarginal ridges MesialDistal Similar to incisors Crown more powerful cervically Mandibular central incisor 71,811  Labial Relativelyflat without eveop ental go Mesial and distal sides become narrower cervically from contact area Root is long and thin narrows to a sharpapex Incisal edge is straight Lingual Cingulum and marginalridgespresent on incisal third crown is flat crown and root narrow lingually Mesial Distal Cervicaloutline morecurved mesially Root nearly flat Mandibular Lateral incisor 72,82 similar to central incisor but slightlylarger in all dimentions except for labio lingually cingulum larger Lingual surface more concave than maxillary Incisal edge shows greatertendencyto descent distal Mandibular canine 73 831 Tooth is smaller especially labio lingually than maxillary Cervical convexity not as prominant Strikingdiff longer distalcuspridge comparedto distal contrasttomaxillary 17. Morphology of deciduous molars. whiter Short root trunks mesiebuccally largebulge Tubercle of Zucker kandI thin Diverging roots 1st Molar 54,641 Maxillary Crown narrows cervically Roots thin long and divergent 3 roots distal root shortest Lingual root thickest short root think Occlusal view buccal surface of crown longer than palatal Two main cusps Buccal Lingual but 4 total Usually one prominent buccal groove shallow central groove but broad Buccal cuspsometimes deridedinto Zor 3 smaller cusps bydevelopmental grooves Palatal cusp usually divided into large mesiopalatal and small distopalatal cusps by distal developmental groove Mesial marginal ridge larger badge Buicalt large mesiobuccal badge called zuckerkandl cusps MP MB DB DPCsometimesmissing Between roots Germof permanent est upper premolar Maxillary 2nd Molar 155,651 Similar to permanent 1st molar but smaller Bulbous shaped crown Narrowed cervically crown l Mestopalatal cusp largest connects to distobucial Obliqueridge low Carabelli often present size burial between Buccal cusps almost same groove Well developed triangular mesial fossa Rhomboidal shaped ordusally it shaped groove system Cusps MP MB DB DP Bucco palatally larger than mesio distally 2nd Perm premolar germ Mandibular 1st Molar 74 84 Does not resemble any other tooth in human dentition Mesial portion of crown more bulbus Zucker RandIs tubercle mesiobucally Occlusal surface rhomboidal in shape mestodistally than buro lingually Longer 4 cusps ML MB DB DL Transverse ridge between mesial cusps 2 roots 4 pulp horns 3 mesial central distal  I AU primarymolars bigger mesiodistally except for maxillary2nd molar Mandibular 2nd Molar Resembles permanent lower first molar but smaller Mesiodistally larger Crown converges lingually Prominent cervical bulge on buccal surface 5cusps 3 buccal and 2 lingual MB SML DL DB D Zigzag shaped fissure 18. Development, physical, chemical properties, structure and formations of enamel. Crown is loweredby enamel it is the outermost layer Hardest and highlymineralized tissue of body t has ectodermal origin Enamel not a living tissue Density of enamel is 2,84 3,00glml A it decreasef from surface to amelodentinal junction - dentinoenamel hysical properties 2 0-2 55 mm thickness : -. a CuSp tip IPO OH 96 98 Inorganic Substances Can y Less than 1 Organic and rest is water = in Outerregions are harder than inner composed of tightly packedrods prisms those are elementary components of enamel n fluorapetite hydroxyl ions replacedby fluoride ions reduce Poth f use fluoridatetoothpaste where dissolve Fluorapetitecrystals are stronger harder and smaller (5. 5 to 4. 5) more packed Color Enamel is semitranslucent Thick enamel is greyish blue whitecolor Thin enamel is yellow white directedtowards incisal and I ly g the tail toward necks enamel rods : key-hole The rods are composed of hexagonal hydroxyapatite crystals shaped different orientation in head crystals are crystals have more regulated than in tail with respect stronger and to tomes Process secretorysurface of ameloblasts Semi-permeable A One ameloblast produces one prism rod Dentin is produced first then Enamel ALWAYS Lines of Retzius Brown lines begin at amelodentinaljunctionand reach surface - - dentinoenamel of enamel (rhythmic deposition) Each line indicates amelogenesis - Lines of retzius form as result of distributed mineralization The place where the lines meet surface of enamel - shallow grooves are seen called perikymata - Bands of Hunter Schrager Langditudal cross sections of enamel viewed by reflected - light appear as light and dark bands found in inner part of enamel Caused by successive changes in direction followed by group of enamel rods in horizontal plane Changein angle of light 18 12prisms Enamel Tufts small branchingdefects foundonly at DEJ projectinginto => enamel have no clinical significance Enamel Spindle Dental tubules found within enamel more abundant in cusp tips Araise when a single odontoblast process invades pre ameloblast layer during dentin development Enamel Lamellae Thin unmineralised structure Primary In anerupted teeth dueto shrinkage ofenamelduring final stages of amelogenesis Secondary In post erupted phase has same appearance but as result of occlusal trauma Crack) Amelogenesis Two main stages 1 Secretorystage in which proteins and organic matrix - form a partiallymineralizedenamel - 2 Maturationstage Mineralisation is completed secretory cells of inner enamel epithelium differentiate to form ameloblasts release enamel proteins Enamel matrix is mineralized A I stratummedicat by enzyme alkaline phosphate Enamel formationcontinues outward away fromdentin After firstlayer the tomes process is produced Maturation AMeloblastsstopsproducingenamel starts to transport proteins used to complete mineralization - what is perikymata Ending part of Ritzus lines can be seen microscopically cementum enameljunction Overlap 60 Meet 30 Gap 10 19. Development, physical, chemical properties structure and formation of dentine. tubular in Dentine forms the main bulk of tooth nature it is composed of * marized 70 inorganic material mainlyhydroxyapatite phosphoproteins nucleus , Identic A DPP is 3 * (group proteins 20 organic mainly collagen and lipids We Osteonectin Dentinsyaloprotein Osteocalzin DPP ↳10 water *** * DSD Osteonectin Osteo it is softer than enamel but harder than cementum inner dentine softer than outer dentine Sentin has a tubular structure therefore dentin has higher sermability than enamel It has nerves so it's sensitive um calcification Dentine is a tooth germ in bell stage macromolecular inner cell of dental papilla will differentiate into odontoblasts tubules ↑44 from DEJ dentinal # tubules z in S-shaped undulation 45000 m I arranged minute - 15000 20, 000 (wisshaped , : structure 0. 9 mm-2-3 mm dentine tubules Types of Dentine enamel Spindle : = that penetrate into Is shaped enamel) shit is for dentire no tubules 1 Mantle Dentine First formed Dentine closestto enamel - - * Von Korft's fibres (collagen type 3) vesicles minerals secreted in DEJ Less mineralized than primarydentine perpendicular to - Homogenous 20 mm thick 2 PrimaryDentine Forms bulk # of tooth a lot regular of tubules It has a veryregularfullytubular formed structure during formation the mu largest when root apex is closed most permiable harder primary dentine is finished -and secondaryafter starts 12-3 years formation occlusion) 3 Secondary Dentine Formedafterroot formation of rest life Formsslower than root less tubular Less regular tubular structure than primary ↓ permi Its deposition- reduces pulpchamber 4 Tertiary Dentine Deposited in reaction to noxious traumatic redures It protects Repirative Dentine stimuli lanes dental pro from pulp Istem the cells alls pulp odontoblast light very few B , Deposited in localised area a irregular tubules Hasveryfew and irregular tubules : 5 Predentine Not completely mineralized 10 20 um wide T layer Remains between odontoblast and mineralised only typeblasts dentine odon cacrete Contains a lot of organic matrix After inorganic materials deposited hydroxyapatite crystals it becomes mineralised to primarydentin ! is mineralised in sphericalforms then spherical forms fuse together and predentine forms primary hysical Properties dentine · trioven or nerco Main bulk of tooth tissue with tubular structure  g Yellowish white in permanent teeth t is a sensitive tissue contains very small nerve branches t is elastic and permable Age affects permeability and hardness acromolecular calcification with age it becomes less permeable ~ with age hardness increases ① minerals produceda proximal end of Odontoblasts Function of Dentine a collage mineralizatio - LI Acts as main portion- of tooth - Protects the pulp ② minerals produces close to mineralization - front - (Phosphoproteins). supports enamel Shelp wo - mineralizations nucleotides inhibi =: - ( Odonto blasts are dentine formingsells proteoglycans Pyrophosphates A single cell layer covers pulpal surface and can have different forms is vitual and They are functioning as living tells as long as tooth when needed they react to stimulus in order to formtertiarydentin Odontoblast processes cytoplasmic extenisons that enter dental are ubules Each process has branches and it has secretoryfunction Dental tubules are narrow parallelchannels that do- not follow a straight course Theyhave two curvatures primary - and secondary s shaped curvature primary are & layerd Secondary curvature can be seen under higher magnification some tubules can penetrate through enamel inside tubules we can find odontoblasts processes and fluid - - Around tubules we can find two kinds of dentine 1 Peri tubular dentine circles tubules like a ring Intra tubular A very hard Highlymineralised Absent in pre dentin and interglobular dentine Its thickness increases with age  2 Inter tubular dentine Found between tubules softer than peri tubular dentine it is built from a well organised - collagen globular granu fiber network sometimes we can small areas in dentine which are not find mineralised We can divide these into two groups rlly * interglobular dentine irregularly shaped structures near AD Crown Identine tubules pass through it) lamelo dentinal junction. Al Granular layer of tomes near cementum seen as dark areas root resultingfromirregular loops ofdentinal tubules 100 mm from pulp is the distance - travel nerves is sensentine bc. hydrodynamic dentine 1960s) Swedish guy (Brannstorm - , theory tubule (high in kt) , when in dentinule or a ↳ Fluid fluid there , Mous , felt, travelled to Stimuli is everythi tissue flownetand We can see different lines of dentine incremental lines due to daily formation of dentine appears as light and dark bands 1 Contour lines ofOwen Differenteventsofmajorchange in bodymetabolismmightcaus hypermineralisation ofdentine 2 Neonatallines lines of von Ebner Hypermineralization - - line can be seen & fine lines onlyin milkteeth or perpendicularpermanent To teeth 3, permenant to tubules firstmolar It molam (represent daily deposition / 4 8M - Dentine formation Dentinogenesis is the first identifiablestage in crown stage and root development it must occur before enamel formation  The different stages result in different kinds of dentine formation Odontoblasts differentiate from dental papilla 20. Development, function and structure of pulp. Dental pulp consists of delicate vascular ionnective tissue with specialized cells The pulp is concerned with reactions of tooth to stimuli # it has 5 main functions 1 Inductive and formative function Interacts with inner enamel epithelium and leads todifferentiation of odontoblasts into dentine 2 Reparative function Acts as a method of protection to isolate pulp from any kind of stimuli low grade attrition 3 Defensive or protective function Causes an inflammatoryresponse in pulp in reaction to acute irritation bacteria deep cavity preparation or irritating filling 4 Nutritive function The blood nourishes dentine and enamel through odontoblast 5 Sensoryfunction stimuli causes pain which acts as a protective function General apparance and structure he dental cavity within each tooth is occupied by dental pulp which ssurrounded by dentine except for apical foramen which is surrounded by cementum Me pulp chamber can be theoretically split into two parts coronal outp and radical pulp root pulp ship communicates with periapical tissue around root through its o ramen Foramen consists of nerves blood and bymy th vessle  as sing throughh Normally we see than one small accessory foramen that connects more root land to periapical tissues he shape of dental pulp is somewhat similar to shapeof tooth he pulp horns are located as small pointed parts ofpulp that are orated beneath cusps up is composed of dentinina cells ↑ ① Odontoblasts found close to predentine outermost layerof pulp ** ⑧ cell free zone layer of Weil beneth odontoblast s cant be seen eses) 40 misu (blood vessels unmyelinated , cytopenin in developing tooth , candriti ③ cell rich zone rich in capillary and nerve network (macrophages , cells , sympocytes fibroblasts most numerous cells of pulp Provides elasticity to blood vessels properl ② pulp Blood vessels Lymthvessels Nerves Min collagenousfibers single both B Sensory , Zuvo A-delta ~ fibres ↳ sharp pain Nerve supply sympathetic Both myelinated and unmyelinated nerve fibers are found in dental axons pulp ** Myelinated are terminal branches oftrigeminal nerve they can register pain they enter root canals and branch cell rich zone out forming plexus of RaschKow - Theybecome unmyelinated as they reach odontoblasts layer Afferent Two types 1to brain are located in walls of blood vessels and innerval Unmyelinated they smooth muscle cells to regulate vasoconstriction Efferent sympathetic nerve system capillary a on frombrain longitudinal axis surface. pulp has arteriovenous anastomosis (B lymphatic vessel ,  2000 A-delta A fibers responsible forstain foundin Raschowplexus C fibers unmyelinated foundin Raschow plexusresponsiblefor - 500 ↳ cell rich dull pain cranial nerve or what happens to A deltafibers Theyloose myelination End free Only Autonomic in odontob mayformgapjunctionswith may loop pulp enterdentinaltubule e /Sympathetic)-superior Diff between A delta and C delta Myelinated unmyelinated cummylented) ganglion trigem a Smooth innervate i may extend muscle cells of anteriol into pulp ,Freeent : calssified masses in pulp Puld Stones (denticle) (falsel mineralized true 21. Development, description of soft tissues of the periodontium. Periodontium consists of 1 Alveolar bone Arise in dentalfollicle 3 gegentumsoft GingivaZ * tooth is sitting in alveolar Socket are soft tissues Gingivaand PDL surrounds teeth alveolar plates ~ buccal 3 lingual Gingiva gum bond to , -pale pink , can tissue epithelium and lamina proprial coloured Soft be Part of gingiva closest to cervical region is not directly attached to tooth and is known as free gingiva marginal In other cases it is known as attachedgingiva teeth Marginal free gingiva it encircles neck of like sonar Attached gingiva covers alveolar bone it is pale pink in color and has orange peal appearance  Only ectodermal tissue from periodontium ~ Stipling buildup Plaque ~ scallop Shape ~ firm , tightly around teeth we have two main parts Histologically outer part Epithelium Lamina propria connective tissue Free gingival groove is the groove that separates attached gingiva from free gingiva We have 3different epithets of marginal gingiva 1 Junctional attached epithet bindsgingiva to tooth 2 Sulcular cervicular epithet above junctional stratified non keratinized 3 Oral epithet facing toward oral cavity keratinized strong Gingival fibers collagen fibers that are found in lamina are ropria and have an important role in maintaining and supporting tooth Fibers work as functional unit but arranged in 5subgroups they are 1 Dentinogingiva between cementum and lamina propria beneath junctional epithelium and marginal gingiva 2 Dentoperiosteal from cementum into periosteummuscle 3 Trans septal from lementum and connects adjacent teeth in arch 4 Alveologingival from bonyalveolar crest to lamina propria 5 Circular run around neck of tooth and maintain tight gingival collar  Interdental gingiva contains all fivegroups illustrated above and trans septal fibers in the posterior region there are oral and vestibular papilla there is a little concave depression between them cot area sensitive The gingiva is supplied by branches of infraorbital nasopalatine burial mental lingualand Palatine arteries Border between attached gingiva and mucosa muso gingiva junction Periodontal Ligament Arai s from dental follicle PDL Middle cells of dental follicle become fibroblasts and produce bone it is is a connective tissue that binds tooth to alveolar it communicates with the bone marrow of alveolar process through vascular channels volkmann's canals cribriform plate The collagen fibers are embedded into alveolar bone as sharpey's fibers The PDL has a vascular supply lymphatics and nerve supply They have nerve fibers that respond to occlusal pressure cell content connective tissue cells Fibroblasts immunologically active cells Macrophages Fibroblasts synthesise fibers that become PDL it is situated within a ground substance mainly composed and glycolipids of glycosaminoglycans glycoproteins Function Supportive formative sensory nutritive and protective and other To withstand the forces of masticatication forces resist light occlusal impact and have slight mobility They cushion as a width of periodontal space is 0,1 0,4mm The periodontal fibers is the most important structural component Collagen ligament There are 5 principle fibers of periodontal 1 Alveolar crest group similar to trans septal fibers run horizontally below alveolar crest 2 Horizontalgroup 3 Oblique group most numerous fibers and found just beneath coronal level 4 Apical group surround the root apex periapisal fibers 5 Inter radicular group at division of root fursation fibers PDL aresupplied by branches of superior and inferior alveolar arteries the apical region is supplied by branches of pupal arteries of individual teeth 22. Development, description of hard tissue of periodontium. The hand tissues of periodontium are cementum and Alveolar bone cementum hamina dural Bone like structure root Covers and protects its color is yellow it is the softest between dental mineralised tissues enamel and dentine because it is It is softer than less minelarised nonmineralized cementum is first produced as soft tissue cementoid precementum deposited along axe mineralization starts when hydroxyapatitecrystals are of lollagen fibers of cementum is called hyalinized layer very first layer and and is very strong bonding layer between dentine cementum to that of bone Its chemical composition is similar 65 inorganic crystals 23 organic lionagent 12 water medium which The main role of cementum is to serve as PDL can attach and stabilise teeth There types of cementum are two 1 Acellular lack of cellular components cover root surface PRIMARY CEMENTUM Fibers sharpey's extrinsic fibers Matrix intrinsic fibers its lamellar structure is regular 50 70 micrometers thin 2 Cellular In the apical third of tooth  SLCON I in lacunae contains cementocytes covers apical third of root and furcation area 200 500 micromemeters thick compensates for enamel wear in it Sharpey's fibers embeded Lamellar structure not well arranged Secondary cementum is the widest Cells of cementum they are cementoblasts 1 Cementocytes cementum sells and are embedded in cementum during cementogenesis to surface spider like cells perpendicular on surface of cementum and 2 Cemento blasts located produce the matrix and fibers of cementum tissue forming cells 3 Cementodasts break down cementum and extrinsic In the cementum we can find intrinsic fibers sharpey's fibers collagen fibers which are embedded into cementum and alveolar bone they are extensions of PDL Cemento enamel junction Edge Edge 30 Gap Between 10 cementum overlaps 60 enamel omtTnaistaae.wnimaw BEdeamemtti.fm functional stage throughout root formationis and occlusion and starts when tooth in which continues throughout life sac 1 Prefunctional from dental forms on root after dentin disintegration of Hertwig epithelial root sheath Lamina Dura of alveolar bone Formed from dental follicle shortly after root development begins Mesodermal origin internal compact layer of alveolar bone 0,1 0,5mm it composed of two parts Bundle bone 7 sharpey's fibers in it Lamellated bone cellular osteocytes lacuna it is located in Lamina dura isbony part of periodontium it is the inner cortical Compact plate of alveolus Bone have Cortical compact plate or area Dense outermost hard layer spongy Tubercular plate inner soft bone with high cell content Lamina dura is outer bone which is faced layer of towards tooth and it lines tooth socket from inside Is produced by osteoblasts Principal fibers of periodontal ligament are anchored and continue into bone lamina dura or cementum assharpey's fibers help to connect bone to tooth Thin plate of cortical bone with numerous perforations for vascular canals Volksmann's canals Cribriform plate that allows passage of blood vessels to PDL outer cells of dental follicle will become osteoblasts and produce alveolar bone Alveolar process is that part of periodontium to which cementum of tooth is attached through PDL tooth socket Alveolar bone proper is bone lining * ③ ⑳ (widest bymentum of Not openining into PDL Canal I furamame foramen, minor apical constriction Clementodentinal Junction). - CDJ of pulp into desmodental - transition distances : 5-1mm 0 -2 : 0. than ② B 5-1 mm to more 0 -normal see. > - : foramen. one accessory - Delta-apicalis