Oral Histo Board Review

8/17/2019 Oral Histo Board Review

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Pharyngeal (branchial)apparatus component

Adult derivative

Branchial arch 1: mandibular arch Muscles of masticationMeckel’s cartilage serves as the guide for the formation of the mandiblemainly by intramembranous ossificationTrigeminal nerve, cranial nerve V

Mandibular prominences form: lower lip, lower face, mandibleMaillary prominences form: middle face, upper lip sides, secondarypalate, maillaTuberculum impar !median tongue bud" AND lateral lingual swellings!distal tongue buds" form anterior #$% of tongue&ateral palatine processes !palatine shelves" form secondary palate

Branchial arch #, hyoid arch Muscles of facial epression'eichert’s cartilage forms hyoid bone(acial nerve, cranial nerve V))

Branchial arch % *lossopharyngeal nerve, cranial nerve )+opula !hypobranchial eminence" forms posterior #$% of tongue

Branchial arch -$. Vagus nerve, cranial nerve +

Branchial pouch, groove, and

membrane 1

/tructures of the ear

Branchial pouch # 0alatine tonsilsBranchial pouch % )nferior parathyroid glands and thymus

Branchial pouch - /uperior parathyroid glandsltimobranchial body becomes parafollicular cells of thyroid

(loor of pharyn Thyroid gland begins as thyroid diverticulum2escends to neck connected via the thyroglossal duct

3dult remnant is the foramen cecum of the tongue

Embryologic structures involved in orofacial development

Name of structure Derivatives Origin

(rontonasal prominence pper 1$% of face 45T of pharyngeal arch originMesenchyme$neural crest

)ntermaillary segment)ntermaillary process*lobular process

0hiltrum of lip, dorsum of nose,primary palate embryologically0remailla in adult

(rontonasal prominence,merging of medial nasalprominences

Maillary prominenceMaillary process

Middle 1$% of faceMailla

(irst pharyngeal arch

Mandibular prominence

Mandibular process

&ower 1$% of face

Mandible


&ateral palatine process0alatine shelves0alatal shelves

/econdary palate embryologicallyMailla in adult

Maillary prominences, firstpharyngeal arch

&ateral lingual swellings2istal tongue buds

3nterior #$% of tongue, oral tongue&ine of merger called medianlingual sulcus


Tuberculum imparMedian tongue bud

Merges with lateral lingual swellingsto form anterior #$% of tongue


6ypobranchial eminenceopula

0osterior 1$% on tongue, base or root of tongue, pharyngeal tongue&ine of merger with anterior #$% iscalled the sulcus terminalis

Third pharyngeal arch


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Meckel’s cartilage *uides formation of mandible, butdoes not contribute to formation of mandible ecept for endochondralossification of the condyle


Stage or structure associated withodontogenesis

unction or characteristic

2ental lamina 7ctoderm derived, forms enamel organ, ameloblasts, crownenamel

Vestibular lamina 45 tooth derivatives, forms lining of the vestibule of the oralcavity

/uccessional lamina The dental lamina of succedaneous teeth, ectoderm derived

7ctomesenchyme Mesoderm !mesenchyme" of pharyngeal arch 1 plus cranialneural crest cells8 (orms all tissues of the tooth and periodontium7+70T for enamel

2ental papilla 7ctomesenchyme, forms dentin and pulp

2ental follicle !sac" 7ctomesenchyme, forms periodontal ligament, cemenum,

alveolar bone)nner enamel !dental" epithelium ells of enamel organ, become ameloblasts, secrete enamel

/tratum intermedium ells of enamel organ, lots of alkaline phosphatase, contribute toenamel minerali9ation

/tellate reticulum ells of enamel organ, lots of etracellular matri between cells

5uter enamel !dental" epithelium Between enamel organ and dental follicle

7namel knot luster of inner enamel epithelial cells, determines crown shapeand cusp number

Morphodifferentiation The physiological or functional process of the determination of theshape of the enamel organ, and thus the tooth crown

6istodifferentiation The physiological or functional process of the differentiation ofameloblasts, odontoblasts, etc8 from precursor cells of the toothgerm

3pposition The successive deposition of the minerali9ed tissues dentin andenamel during formation of the crown of the tooth


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Dentin cell or structure unction or characteristic

5dontoblast

2erived from dental papilla4eeds inner enamel epithelium for odontoblasts to form)n the erupted vital tooth, there is a single row of columnar odontoblasts thatare active as long as the tooth is healthyell bodies located in the pulpell processes are within dentinal tubules that may run from 27 or 7 tothe tooth surface

0re;dentin The organic fibrillar matri of dentin that contains collagen type ) fibers

2entin ontains hydroyapatite !630" crystals at average

0attern of dentin formation

2entin secretion is called apposition, the crown stage of odontogenesis

2entin formation starts at the occlusal or incisal surface of a crown andproceeds apically !cervically"5nce crown dentin is formed, root dentin formation begins2entin under cusps is the ?oldest@ dentin in a tooth

2entinal tubules

ontain an odontoblastic process, an aon, dentinal fluid, collagen0rimary curves !/;curves" reflect the migration of odontoblasts as theysecreted dentin0rimary curves are more numerous and have a greater curvature in thecrown compared to the root2entinal tubules impart a porosity to dentin, may allow bacteria to get to thepulp

0rimary dentinlosest to the enamel or cementum, dentin formed first5dontoblasts are highly secretory during formation of primary dentin

Mantle dentin 0rimary dentin closest to the enamel or the cementum

/econdary dentin

0hysiological dentin, dentin formed after the tooth erupts and comes intoocclusion5dontoblasts secrete dentin continuously throughout the life of a tooth, butat a slow rate6istologically, the interface between primary and secondary dentin can be

seen because the angle of the dentinal tubules changes here

ircumpulpal dentin 3ll dentin that is 45T mantle dentin, includes both primary and secondarydentin, represents the bulk of dentin in an erupted vital tooth

)ntertubular dentin 2entin around and between dentinal tubules

0eritubular 5' intratubulardentin

2entin lining the dentinal tubulesM5/T 6)*6&A minerali9ed type of dentin !hyperminerali9ed"


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/clerotic dentin2eposition of minerals within the dentinal tubules, leading to the completeblocking or occlusion of the tubules, results in transparent dentinMay be a phenomenon to protect dentin from bacterial invasion

*lobular dentin2entin in the form of calcospheres or globules, the form of dentin at the

beginning of minerali9ation, located at the minerali9ation front between pre;dentin and dentin

)nterglobular dentin

'egions of hypominerali9ed dentin between globular dentinMost likely to be located at boundary of mantle and circumpulpal dentin, orin dentin formed during periods of vitamin 2 deficiency or high fluorideeposure

Tertiary dentin*eneral term for the dentin formed in an erupted tooth that has beendamaged, infected, or subected to restoration proceedures

'eactive dentinTertiary dentin formed by pre;eisting odontoblasts that were not killed bythe damage done to the tooth

'eparative dentinTertiary dentin formed by 47C odontoblasts, most likely from theundifferentiated mesenchymal cells found in the pulp

Tomes’ granular layer 6istological feature of dentin located beneath the dentinocementum unction

2ead tracks6istological feature of dentin seen only in ground tooth sections'epresent empty dentinal tubules that are filled with air, appear black

)ncremental lines of von7bner

6istological feature of dentin, represent D day increments of odontoblastactivity and secretion of dentin

ontour lines of 5wen 6istological feature of dentin, represent physiological alterations in dentinformation while tooth was still in the oral cavity !not erupted"

4eonatal line 3n eceptionally prominent contour line of 5wen in the crown dentin'epresents a disruption in odontoblast activity during birth


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Enamel cell or structure unction or characteristic

7namel organ 2erived from dental lamina !ectoderm", forms crown enamel

)nner enamel epithelial cells0art of the enamel organ, differentiate into ameloblasts under theinfluence of dentin and odontoblasts

Morphogenic stage of ameloblasts )nner enamel epithelial cells touching basement membranebetween enamel organ and dental papilla become preameloblasts

5rgani9ing stage of ameloblastsells become columnar and polari9e E secretory end near thebasement membrane and nucleus away from it

(ormative stage of ameloblasts 3prismatic enamel is secreted at the basement membrane, formsthe dentinoenamel unction

/ecretory stage of ameloblasts

The Tome’s process is formed at the end of the ameloblast near thedentinoenamel unction7namel rods and interrod enamel is formed'od and interrod enamel differs only in the orientation of 630crystals

Maturation stage !maturativestage" of ameloblasts 4o enamel matri is secreted, the eisting matri is minerali9ed to

F.> by the cyclic removal of water and proteins and the addition ofcalcium and phosphate to form 630 crystals

0rotective or desmolytic stage ofameloblasts 3meloblasts shrink in si9e, and all four cell layers of the enamel

organ collapse and flatten on to the surface of the enamel to formthe reduced enamel epithelium !'77"8 '77 remains with the toothfor the rest of development, then forms the initial unctionalepithelium via its fusion with oral epithelium during eruption8

7namel matriontains enamelins, amelogenins, and ameloblastin45 collagen in enamel matri)mmediately minerali9ed to about %=>

7namelF.> 630 crystals45 collagen

7namel formation7namel is first formed at the occlusal or incisal region of the crownand proceeds cervically to the cervical loop

Bands of 6unter;/chreger 6istological feature of enamel, alternating dark and light bands withpolari9ed or reflected light8 'epresent the orientation of enamelrods during the preparation of the ground tooth sections

7namel cross striations6istological feature of enamel that represents the daily elongationof 630 crystals

/triae of 'et9ius6istological feature of enamel that represents


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4eonatal line 3 broad striae of 'et9ius in enamel, represents a physiologicaldistruption in enamel formation because of birth

7namel lamellae or cracks 3n enamel defect that begins at the enamel surface and which mayetend all the way through the enamel into dentin

They may contain enamel proteins, salivary protein, or debris

7namel tufts(an;shaped hypominerali9ed structures that are attached to the27 and etend into enamel

7namel spindle'epresent odontoblastic processes that start at the 27 and etenda short distance into the enamel8 7namel minerali9es around theprocesses

*narled enamel 3 region of twisted enamel rods at the tooth cusps

0erikymata'epresent the surface manifestations of striae of 'eti9us8 They areseen as linear, parallel surface depressions

(luorapatite (luoride ion can substitute for the hydroyl groups inhydroyapatite, forming fluorapatite8 (luroapaptite is more resistanttoacid solubili9ation

!ementum cell or structure !haracteristic or unction 1 3


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ementoblasts uboidal cells located on the surface of cementum facing the 02&

ementocytesG ells surrounded by minerali9ed cementum8ells reside in lacunae and have cell processes within canaliculianaliculi are polari9ed towards the 02& for nutrient support

0re;cementum or cementoid 5rganic fibrillar cementum matri, contains collagen type ) and manyproteins similar to bone

ementum Minerali9ed with 630 crystals to -D;.D>, using an average of D=>results in cementum with the mineral content closed to bone

)ntrinsic fibers ollagen type ) fibers secreted by cementoblasts

7trinsic fibers ollagen type ) fibers, also called /harpey’s fibers8 /ecreted by 02&fibroblasts8 These are the fibers found in the 02& that insert into thecementum

3cellular etrinsic fibercementum !37("

overs cervical #$% of the root8 The function is to anchor the root ofthe tooth to the 02& via the /harpey’s fibers of the 02&

ellular intrinsic fiber cementum!)("

&ocated at tooth furcation, apical portion of root, old resorptionlacunae, root fracture sites8 4ot as important in tooth attachment as

37(, but can form Guickly to repair cementum damage

ementum distribution ementum is thickest apically)t is deposited slowly throughout the life of the tooth, mainly as

cellular cementumellular cementum compensates for occlusal wear

)ncremental lines )ndicate the periodic appositional growth of cementum

'eversal lines )ndicate the resorption of cementum, site of deposition of newcementum

ementoenamel unction ementum overlaps enamel at the 7 in .=> of sections eaminedementum and enamel form a butt oint or meet end to end in %=>There is a gap between enamel and cementum in 1=>

ementicles 3 globular mass of cementum found free in the 02&, attached to thecementum surface or embedded in cementum

6ypercementosis 7cessive deposition of cementum on the root surface

"E#S cell or structure unction or characteristic

67'/ H 6ertwig’s epithelial rootsheath

3 bilayer of inner enamel epithelium and outer enamelepithelium growing from the cervical loop following thecompletion of crown enamel and dentin formation

'oot dentin formation The inner enamel epithelium of 67'/ induces the formation ofodontoblasts from dental papilla

'oot cementum formation (ollowing root dentin formation, 67'/ degeneratesells of the dental follicle contact the root dentin, becomecementoblasts, and form cementum

7pithelial rests of Malasse9 )slands of 67'/ cells that do not degenerate'emain in the 02& in the erupted toothMay form periapical cysts

'oot length 67'/ determines the length of the root by continualproliferation of inner and outer enamel epithelium

4umber of roots 2etermined by the epithelial diaphgram of 67'/'esults from uneGual proliferation of the cells of the diaphragm

2ilaceration 3n etreme bend in a root, caused by dislocation of 67'/ fromthe developing root surface

3ccessory root canal&ateral canal

'esults from a disruption in 67'/ prior to the formation of rootdentin leading to eposed pulp

7posed root dentin 'esults from a lack of 67'/ degeneration, so cementoblastscannot contact the forming root to secrete cementum on thedentin

7namel pearl 7ctopic deposition of enamel along the root by inner enamelepithelial cells of 67'/


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Alveolar bonestructure$%&'

!haracteristic or unction

3lveolar process 3lveolar bone proper, ancellous bone, ortical plate

Basal bone ancellous bone and cortical plate that supports the alveolar process

3lveolar bone proper The compact bone immediately surrounding the tooth, bone of the alveolar socket

&amina dura 'adiographic term for alveolar bone proper, radiopaGue line around the root

Bundle bone 6istological term for alveolar bone proper, site where /harpey’s fibers of the 02&insert into the tooth

ribriform plate 3natomical term for alveolar bone proper, refers to the foramina in the bone thatallow blood vessels and nerves to pass through to the tooth

3lveolar boneremodeling

Bone is remodeled more freGuently and more easily than cementum0ressure or compression results in bone resorptionTension results in bone formation

Mandible formation The maority of the mandible forms around Meckel’s cartilage byintramembranous ossification, the condyle continues to form by endochondralossification because it is a secondary hyaline cartilage until about age %=

TM 3rticulating surfaces are covered by dense fibrous connective tissue especially inaged persons)n persons under age %= hyaline cartilage will be present

The most vascular and highly innervated region of the articular disc is thebilaminar 9one

Pulp component or cell !haracteristic or unction

7mbryological derivation 2ental papilla, ectomesenchyme

Maor cell type (ibroblast, functions to produce the etracellular matriollagen type ) fibers predominate0ulpal fibrosis is accumulation of collagen fibers

0ulp cell: odontoblast 5dontoblast cell bodies are at the dentin;pulp interface5dontoblasts form reactive dentin !tertiary dentin" if a minor inuryoccurs to tooth that does not epose pulp5dontoblasts continually produce secondary dentin

ndifferentiated mesenchymalcell

an become odontoblasts and form reparative dentin !tertiary dentin"following a severe tooth inury that eposes pulp and kills thepreeisting odontoblasts

2entin;pulp comple 4erves enter from apical foramen(orm the subodontoblastic pleus !of 'ashkow" under odontoblasts

3ons travel within dentinal tubules

Brannstroms hydrodynamictheory of dentin sensitivity

Based on the movement of fluid in dentinal tubules 3ll sensations are perceived as pain

3 delta !3S" fibers Myelinated and fast;conducting aons/harp, well;locali9ed pain that goes away when the stimulus isremoved

fibers nmyelinated and slow;conducting aons2ull, poorly locali9ed, throbbing pain that may be associated withinflammation


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0ulp stones or denticles alcified tissue in pulp formed by odontoblastsTrue, false, attached, and free pulp stones

PD component or cell !haracteristic or unction

7mbryological derivation 2ental follicle !sac", ectomesenchyme

02& fibroblasts 0roduce collagen type ) fibers of the principal fiber groups0roduce etrinsic fibers !/harpey’s fibers" that insert into bone andcementum to anchor the 02& principal fiber groups

7tracellular matri ollagen type ) fibers mainly, also collagen type )))5ytalan fibers, a type of elastic fiber

02& principal fiber groups 3lveolar crest group: ementum to bone6ori9ontal group: ementum to bone5bliGue group: ementum to bone

3pical group: ementum to bone)nterradicular group: ementum to boneTransseptal group: ementum to cementum

5bliGue group Most numerous 02& principal fiber group, so most important for 02&anchorage of tooth to alveolar bone

Mechanoreceptors 'uffini encapsulated nerve ending is the primary mechanoreceptor

ingiva component or cell !haracteristic or unction

Marginal gingiva (ree gingiva, free gingival margin, free marginal gingival*ingiva nearest the surface of the tooth, but not attached to the tooth

3ttached gingiva *ingiva firmly attached to alveolar bone and tooth cementum7tends from free gingival groove to the mucogingival unction

)nterdental gingiva *ingiva that fills the interdental spaces

/ulcular epitheliumrevicular epithelium

/tratified sGamous parakeratini9ed or nonkeratini9ed epithelium

'elatively nonpermeable epithelium lining one side of the gingivalsulcusMain function is protection

5ral epithelium /tratified sGuamous orthokeratini9ed or parakeratini9ed epithelium5n oral side of both marginal and attached gingivalMain function is protection

unctional epithelium /tratified sGuamous nonkeratini9ed epitheliumBasal cells attach to eternal basal lamina on lamina propria side withhemidesmosomes/uprabasal cells attach to the tooth surface with inner basal laminaand hemidesmosomesVery permeable epithelium allowing for bidirectional movement offluids, cells, bacteria and cell$bacterial secretions


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7pithelial attachment )nternal basal lamina plus hemidesmosomes, the structures thatfunction to attach the unctional epithelium to the tooth

7mbryological origin unctional epithelium arises from ectoderm initially as the reducedenamel epithelium as it peels back along the sides of the eruptingtooth8 This is called initial unctional epithelium5ral and sulcular epithelium arise from ectoderm

Gingivodental group of fibers Location

Circular group Gingival fibers located coronal to the PDL transseptal fibers that run in

a circumferential or semicircular manner around the teeth. They

encircle the teeth.

Dentogingival group Fibers that are inserted into cementum of the root surface as harpey!s

fibers and then fan out from the root surface sub"acent to the "unctional

epithelium and coronal to the alveolar crest into the gingival tissues

Dentoperiosteal group Fibers that are inserted into cementum of the root surface# run over the

alveolar crest# and insert into the periosteum of alveolar bone

$lveologingival group Fibers that arise at the alveolar crest and fan out into the free and

attached gingiva

Oral cavity !lassification Salivary gland Other characteristics

)nner lip&abial mucosa

&ining mucosa &abial mied minorglands

Transition from skin !orthokeratini9ed"to labial mucosa !nonkeratini9ed" is thered or vemillion border

heekBuccal mucosa

&ining mucosa Buccal mied minor

glands(loor of mouth &ining mucosa 3reas in the oral cavity with a liningmucosa allow for uptake or absorptionof some medications because theepithelium and lamina propria isrelatively thin

Ventral tongue &ining mucosa &ingual mucousminor glands at thebase of the tongue

3lveolar mucosacovering alveolar bone

&ining mucosa 4one

/oft palate, oralsurface

&ining mucosa Minor mucouspalatine !palatal"glands


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*ingiva Masticatorymucosa

4one /ulcular epithelium is parakeratini9edor nonkeratini9ed5ral epithelium is ortho orparakeratini9edunctional epithelium is nonkeratini9ed

6ard palate Masticatory

mucosa

Minor mucous

palatine glands in theglandular 9one,adipose tissue in thefatty 9one

Mucoperiosteum: The epithelium with

underlying lamina propria is directlyattached to the bones of the palate withno intervening muscle

2orsal tongue /peciali9edmucosa

Minor lingual mucousglands at the base of the tongue

/peciali9ed mucosa is keratini9edstratified sGuamous epithelium withpapillae and taste buds

&ining mucosa means the epithelium is stratified sGuamous nonkeratini9ed• Masticatory mucosa means the epithelium is stratified sGuamous parakeratini9ed or

orthokeratini9ed

• /peciali9ed mucosa means the epithelium has papillae and is keratini9ed

• /erous means the gland contains cells that secrete a watery protein;rich product

• Mucous means the gland contains cells that secrete mucins that hydrate to mucus in the oral

cavity

• Mied means the gland contains cells that secrete both a serous and a mucus product

&a*or salivary gland component unction or characteristic

0arotid gland 3ll serous;secreting, main duct is /tensen’s duct 3ccumulates fat with age

/ubmandibular gland Mied gland with a predominance of serous cells, main duct isCharton’s duct, maor contributor to unstimulated salivaMost commonly affected by sialolithiasis

/ublingual gland Mied gland with a predominance of mucous cells, ducts are ductsof 'ivinius or Bartholin

)ntercalated duct /imple cuboidal epithelium, first to receive secretions from salivary

duct cells/triated duct /imple columnar epithelium with basal striations, modifies saliva

'emoves 4a and l ions from saliva, adds potassium andbicarbonate saliva/alivary flow rates determine the concentrations of these ions

Myoepithelial cells ontractile properties function to sGuee9e products from cells

%ongue component unction or characteristic

(iliform papillae 5n dorsal surface of anterior #$% of tongueMost numerous, spikes of keratini9ed epithelium pointing towardsthe pharyn, no taste buds

(ungiform papillae 3nterior #$% of tongue between the filiform papillaeBlood vessels close to surface impart red color/ome taste budsTaste bud innervation: (acial nerve

(oliate papillae 3nterior #$% of tongue, on lateral aspect/ome taste budsTaste bud innervation: (acial nerve

%


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ircumvallate papillae &argest in si9e and fewest in number 3t the sulcus terminalis, unction of anterior #$% and posterior 1$% oftongueMany taste buds, innervation of taste buds is the glossopharyngeal/erous glands of von 7bner are associated with these papillaeThe only purely serous minor salivary gland

Base of tongue 4o lingual papillae&ingual minor salivary glands are all mucous&ymphatic tissue as nodules

Ventral tongue 4o papillae or taste buds/tratified sGuamous nonkeratini9ed epithelium

land !lassification ocation &ethod of secretion

/alivary 7ocrineompound tubuloalveolar

5ral cavity 7ccrine or merocrine

/weat 7ocrine/imple coiled tubular

2ermis of skin 7ccrine or merocrine

/ebaceous 7ocrine/imple acinar

Cith hair follicles 6olocrine

von 7bner 7ocrineompound tubuloalveolar

&amina propria ofcircumvallatepapillae

7ccrine or merocrine

Oral Histo Board Review

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