Mouth (oral cavity) and Teethnikolai.lazarov.pro/files/medicine_eng_splanchnology/Mouth_and_Teeth.pdfTooth abnormalities of size and form 33 Anodontia: a complete lack of tooth development

1. Oral cavity: vestibule oral cavity proper

2. Floor of the oral cavity3. The human dentition –

permanent and deciduous teeth4. Tooth development (odontogenesis)5. Eruption of the deciduous and permanent teeth6. Abnormalities of teeth

Mouth (oral cavity) and Teeth

Statue at Buddha Park, near Vientiane, Laos

SPLANCHNOLOGY

Prof. Dr. Nikolai Lazarov

Oral cavity, cavitas oris

2

Cavitas (cavum) orisGr. stoma, stomatos: located in the face

oral fissure, rima oris

throat (fauces), isthmus faucium

Parts: oral vestibule, vestibulum oris

parotid papilla, papilla ductus parotidei

oral cavity proper, cavitas oris propria

boundaries:o gums and teeth

o hard palate

o part of the soft palate

o oral floor, diaphragma oris

content:o tongue

o teeth

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Prof. Dr. Nikolai Lazarov 3

Lips, labia oris

Macroscopic anatomy:

oral fissure, rima oris

angle of mouth, angulus oris

commissure of lips, commissura labiorum

Upper lip, labium superius:

medial and two lateral parts

frenulum of upper lip

nasolabial fold, sulcus nasolabialis

philtral ridges, philtrum

tuberculum labii superioris

Lower lip, labium inferius:

frenulum of lower lip

mentolabial fold, sulcus mentolabialis

buccolabial fold, sulcus buccolabialis

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Lips, labia oris Microscopic structure:

external surface, skin multilayered stratified keratinizing squamous epithelium

hair follicles, sebaceous and sweat glands

vermilion border, modified skin transparent epithelium

rich microvasculature – red margin

internal surface, mucous membrane stratified nonkeratinized squamous

seromucous labial glands

internally – orbicularis oris muscle fibroadipose connective tissue, rich in

nerve fibers and blood vessels

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Cheeks, buccae

Macroscopic anatomy:

form the sides of the mouth

similar to lips structure

composed externally of integument

muscular stratum – m. buccinator

buccal fat-pad tissue (of Bichat) –

corpus adiposum buccae (Bichat)

composed internally of mucous membrane

5

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Cheeks, buccae

6

Histological structure:

external surface – hairy skin:

stratified keratinized squamous

epithelium

hair follicles, sebaceous and sweat glands

the buccinator muscle, m. buccinator

internal surface – buccal mucosa

stratified non-keratinized squamous epithelium

with a high regenerative capacity

buccal and molar glands

buccal fat-pad tissue (of Bichat)

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Oral cavity proper, cavitas oris propria

Palate, palatum:

roof of the oral cavity proper

resonance in phonation

hard palate, palatum durum (osseum)

soft palate, palatum molle

Hard palate, palatum durum – anterior ⅔:

processus palatinus maxillae

lamina horizontalis ossis palatini

plicae palatinae transversae

papilla incisiva; raphe palati

gll. palatinae

stratified non-keratinized squamous

epithelium keratinization

lamina propria – firmly attached

to the periosteum

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Palate, palatum:

roof of the oral cavity proper

resonance in phonation

hard palate, palatum durum (osseum)

soft palate, palatum molle

Hard palate, palatum durum – anterior ⅔:

processus palatinus maxillae

lamina horizontalis ossis palatini

plicae palatinae transversae

papilla incisiva; raphe palati

gll. palatinae

stratified non-keratinized squamous

epithelium keratinization

lamina propria – firmly attached

to the periosteum

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Soft palate, palatum molle – posterior ⅓

velum palatini with uvula

arcus palataglossus and

arcus palatopharyngeus

stratified columnar epithelium nasally

stratified non-keratinized squamous orally

muscles of the soft palate

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Gums, gingivae:

attached gingiva

marginal gingiva

Macroscopic structure:

free gingival margin

gingival sulcus

gingival papilla (interdental papilla)

vestibular

oral

Microscopic structure:

lamina epithelialis

stratified squamous parakeratinized

epithelium

lamina propria – papillae

rich vascularization

dense innervation


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Floor of the oral cavity

Oral floor:

a muscular layer between the tongue and the mandible

Muscular base: mylohyoid, m. mylohyoideus

geniohyoid, m. geniohyoideus

Mucosa:

thin and loosely attached to the underlying structures

mucosal folds

lingual frenulum

sublingual folds

sublingual papilla (caruncle)

Blood supply and venous drainage: aa. et vv. sublingualis, facialis et thyroidea sup.

Lymphatic drainage: nodi lymphatici submandibulares et cervicales profundi

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Floor of the oral cavity

Oral floor:

a muscular layer betweenthe tongue and the mandible

Muscular base: mylohyoid, m. mylohyoideus

geniohyoid, m. geniohyoideus

Mucosa:

thin and loosely attached to the underlying structures

mucosal folds

lingual frenulum

sublingual folds

sublingual papilla (caruncle)

Blood supply and venous drainage: aa. et vv. sublingualis, facialis et thyroidea sup.

Lymphatic drainage: nodi lymphatici submandibulares et cervicales profundi

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Oral cavity – first pharyngeal arch

maxillary process

mandibular process

frontonasal prominence

middle part of nasal prominence

lateral parts

Nose:

frontonasal prominencenasal root

two medial nasal prominences nasal dorsum and apex

two lateral nasal prominences nasal sidewalls and alae

nasal (olfactory) placode nostrils

Eye – eye rudiments:

lateral nasal prominences

maxillary processes

Embryonic development

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Facial abnormalities Facial clefts:

cleft lip, labium leporinum (harelip)

cleft palate, palatum fissum(palatoschisis s. faux lupina)

congenital macrostoma

congenital microstoma

congenital cleft in the face, meloschisis

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Teeth, dentes

15

Teeth, dentes (Gr. odus, odontos):

mechanical breakdown (chew) of food

help in phonation

derivatives of oral mucosa – cornified papillae

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Phylogenetic development of teeth

16

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Teeth, dentes

17

Characteristics of human dentition:

close contact between teeth

heterodont dentition (Gr. “different teeth”) – teeth differ both morphologically

and functionally

teeth have the same general structure, regardless of their functional segregation

diphyodont dentition – two successions of teeth (two types of dentition)

in a process of evolution – reduction in tooth number

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Dental morphology

18

Anatomical parts of a human tooth: tooth crown, corona dentis – surfaces

margo incisialis (incisivus) – incisors

facies occlusalis (masticatoria) –premolars and molars

o tuberculum dentale (cuspis dentalis)

facies vestibularis (labialis, buccalis)

facies lingualis

facies contactus (mesialis et distalis)

anatomical vs. clinical crown

tooth neck, cervix dentis tooth root, radix dentis – in dental alveolus

apex radicis dentis

dental cavity –cavitas dentis (pulparis) cavitas coronae

canalis radicis dentis

tooth pulp, pulpa dentis pulpa coronalis

pulpa radicularis

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Basic tooth structure

19

Tissue components of the tooth crown: dental cuticle, cuticula dentis – 5-30 µm

ectodermal origin

an amorphous layer thatcovers the tooth crown

non-mineralized layer of organic material

o proteins, glycosaminoglycans

enamel, enamelum(substantia adamantina) ectodermal origin

the hardest substance in the body –thickness 0.01 (tooth neck)-2.5 mm

acellular and nonreplaceable

highly mineralized substance – 96-97%

o hydroxyapatite crystals

o closely packed enamel prisms, prisma

enameli and interprismatic substance

organic matrix – 2-3%

o fibrous keratin-like glycoproteins

produced by secretory ameloblasts enamel defects – dental caries

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Tissue components of the tooth root: dental cement, cementum – mesenchyme

hard, avascular material covering the tooth root

bone-like tissue:

o mineral intercellular substance,

substantia intercellularis cementi

• calcium hydroxylapatite – 45-50%

• organic matter and water – 50-55%

• numerous fibrils of type I collagen

• glycoproteins and proteoglycans

o cells, cementocyti

• located in lacunae

• joined together by canaliculi

o the cement is destroyed by odontoclasts

in the tooth neck – acellular cement

o location of tooth decay

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21

Tissue components of the tooth:

dentin, dentinum (substantia eburnea)

located in the tooth crown, neck and root

elastic, yellowish-white, avascular tissue

hard, bone-like tissue:

o inorganic matter – 70%

• calcium hydroxylapatite crystals and

amorphous calcium phosphate

o organic matrix (collagen) – 20%

o water – 10%

o cells, odontoblasts with long

cytoplasmic processes of Tomes

in dentine canals (dentinal tubules)

dentin layers:

o mantle (0.5 mm) – closest to enamel

o predentine – innermost

o secondary dentin

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22

Tissue components of the tooth:

dental pulp, pulpa dentis

inside the dental (pulp) cavity

o crown – pulp chamber

o root – root canal(s)

undifferentiated mesenchyme soft loose connective tissue

microscopic structure:

o cells – odontoblasts and dentinoblasts

• numerous fibroblasts

• undifferentiated mesenchymal cells

• macrophages, monocytes and lymphocytes

o collagen fibers

o ground substance

o abundant myelinated and unmyelinated fibers

o richly vascularized – nutritive function

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Periodontium

23

Attachment apparatus of a tooth – gomphosis

the tissues investing and supporting the teeth

Periodontium (Gr.περι, around + οδονσ, tooth):

alveola dentalis

periosteum alveolare (insertionis)

lig. periodontale

cementum radicis dentis

periodontium protectoris (gingiva)

Desmodontium (Sharpey fibers) – fibroblasts

Parodontium (in German) – functional unit

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Human dentition

24

Permanent teeth, dentes permanentes:

32 teeth into two symmetrical halves

upper dental arch, arcus dentalis superior

lower dental arch, arcus dentalis inferior

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Human dentition

25

Permanent (adult) teeth,dentes permanentes:

anatomical and functional groups:

incisors, dentes incisivi

canine (dogteeth), dentes canini

premolars, dentes premolares

molars, dentes molares

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The adult human dentition

26

Coding of the permanent teeth: dental formulae for humans:

anatomical – I2C1P2M3

clinical

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Dental radiology

27

Dental

panoramic radiography

(Orthopantomography)

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Incisors, dentes incisivi

28

The incisor teeth, dentes incisivi: used to incise food

total number – 8 (2 in each

jaw quadrant: 4 upper and 4 lower)

crown, corona dentis – chisel shaped

biting edge, margo incisialis

labial surface (facies labialis)

lingual surface – tuberculum dentale

contact surface (mesial and distal)

root, radix dentis – conical shape

root apex, apex radicis dentis

medial (central) incisors

lateral incisors – smaller in size to absent

diastema

“lucky teeth”

cosmetic dentistry

dental consonants

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Canines, dentes canini

29

The canine (dog)teeth, dentes canini:

used primarily for firmly holding food

the longest teeth in mouth – 25 mm in the root

total number – 4 (two in the upper – eye teeth, and two in the lower arch)

root – single, longer and thicker, conical in form

apex radicis dentis – compressed laterally

crown – large and conical; occlusal surface

labial surface – very convex

lingual surface – mesial and distal lingual fossae

tuberculum dentis

sexual dimorphism

much larger in the males than in the females, or are absent in females

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Premolars, dentes premolares

30

The premolar teeth, dentes premolares:

primary functions of both molars and canines in chewing

total number – 8 (two per quadrant) – first and second premolars

crown – quadrangular with at least two cusps – buccal and palatal

occlusal (masticatory) surface (lingual)

buccal surface – quite rounded

lingual surface – rounded in all aspects

root – single (except the maxillary first premolar)

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Molars, dentes molares

31

The molar teeth, dentes molares:

serve to chew, crush and grind food

the largest of the teeth in mouth

total number – 12 (six upper and six lower)

crown – cube-shaped

occlusal surface

o 4-5 cusps

o tuberculum anomale (cusp of Carabelli)

roots – multiple and separated

upper jaw – 3

(two labial and one palatal)

lower jaw – 2

dens serotinus

(wisdom tooth)

generally appear between

the ages of 17 and 25

may never erupt

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Dental arches

32

Dental arches – upper and lower:

superior dental arch, arcus dentalis superior:

larger and semi-ellipsoid

inferior dental arch, arcus dentalis inferior:

has a parabolic shape

dental occlusion and articulation

Orthognathism (Gr. orthos – straight, gnathos – jaw)

Progenism vs. Prognathism

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Tooth abnormalities of size and form

33

Anodontia:

a complete lack of tooth development

rare, most often occurring in a condition

called Hypohidrotic ectodermal dysplasia

Hypodontia:

a lack of some tooth development

affecting 3.5–8.0% of the population

absence of third molars - 20–23%

second premolar and lateral incisor

Hyperdontia:

development of supernumerary teeth

develop from a second tooth bud

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Congenital syphilis – Hutchinson’s teeth:

smaller and more widely spaced teeth

have notches on their biting surfaces

Rickets (rachitis):

delayed and abnormal sequence eruption

dental deformities

enamel defects

Hypocalcemic tetany:

serious abnormalities of enamel of the

canine and molar teeth – hypoplasia

malformed teeth

Elderly face:

alveolar ridge resorption loss of teeth

jaw atrophy

Abnormalities in tooth shape

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Embryonic development of teeth

35

Odontogenesis – around 6th week

molecular control of tooth development transcription factor Lef-9; FGF-8

signaling molecules BMP-2, -4 and -7

homeobox genes

tooth bud (germ) – origin

ectoderm

lamina dentalis

organum epithelum (dentis)

o enamel – amelogenesis

mesenchyme

gemma dentis (papilla dentis)

o dentin – dentinogenesis

o tooth pulp

cementum – cementogenesis

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Histogenesis of dental tissue

36

Odontogenesis:

amelogenesis

enamel organ – bell stage:

o outer enamel epithelium – cuboidal

o enamel pulp, pulpa enamelea

o inner enamel epithelium –

simple columnar epithelium

proameloblasts ameloblasts

dentinogenesis

preodontoblasts young

odontoblasts predentin

mantle dentin

mineralization (maturation) of

predentin apatite crystals

cementogenesis

mesenchymal cells of dental sac

cementoblasts

tooth root development

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Human dentition

37

Deciduous (milk) teeth, dentes decidui: the first set of teeth in the growth

development of humans 20 teeth into two symmetrical halves distinguishing features (traits):

similar morphology; smaller in size slightly blue tone of enamel shorter roots wider root canals and cavity

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Human dentition

38

Deciduous teeth, dentes decidui:

anatomical and functional groups:

incisors, dentes incisivi – 2

canine teeth, dentes canini – 1

molars, dentes molares – 2

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The human deciduous dentition

Coding of the deciduous teeth: human dental formulae –

an expression in symbols of the number and arrangementof teeth in the jaws:anatomical – I2C1M2

clinical

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Human tooth development timeline

40

Deciduous tooth eruption: begin – 6th mo.

central incisor

end – 2nd-3rd yrs.

second molars

formed temporary dentition until 5-6 years of age

Permanent tooth eruption: begin – 5th-6th yrs.

first (six-year) molar

end – 18-30 yrs.

third molar

(wisdom tooth)

Deviations from the established norms:

precocious dentition, dentitio praecox

delayed dentition, dentitio tarda

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Disturbances in tooth formation

41

Dilaceration:

a disturbance in shape of teeth

due to trauma during the period in which tooth is forming

Enamel hypoplasia:

defective enamel matrix formation with a deficiency in the cementing substance

tooth enamel:

hard but thin

deficient in amount

Turner’s hypoplasia:

a tooth enamel defect

missing or diminished enamel

usually affects only one tooth in the mouth (Turner’s tooth)

associated with the dilaceration

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Blood supply of the teeth

42

Upper tooth row:

molars

rr. dentales of a. alveolaris superior posterior

the remaining teeth

rr. dentales of a. alveolaris superior anterior

Lower tooth row: rr. dentales of a. alveolaris inferior

Venous drainage: plexus venosus pterygoideus vv. maxillares

v. retromandibularis

v. facialis

Lymphatic drainage: teeth in upper jaw submandibular nodes

parotid and supraclavicular nodes

teeth in lower jaw submental and submandibular

nodes cervical and paratracheal nodes

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Innervation of the teeth

43

Teeth and gums in upper jaw:

nerve plexus formed by the

infraorbital nerve:

rr. alveolares superiores anteriores

rr. alveolares superiores posteriores

r. alveolaris superior medius

rr. dentales superiores

rr. gingivales superiores

Teeth and gums in lower jaw:

n. alveolaris inferior

plexus dentalis inferior:

rr. dentales inferiores

rr. gingivales inferiores

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Thank you ...

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Mouth (oral cavity) and Teethnikolai.lazarov.pro/files/medicine_eng_splanchnology/Mouth_and_Teeth.pdfTooth abnormalities of size and form 33 Anodontia: a complete lack of tooth development