Development of Palate,Tongue, Maxilla and Mandible

Development of Palate,Tongue, Maxilla and MandiblePresented By,Dr.AldrinJerry.J(First Year Post Graduate)Department of Oral Pathology

Content

IntroductionTerminologiesPharyngeal ArchEarly Oro-facial structuresDevelopment of PalatePrimary palate formationSecondary palate formationDevelopmental defect of PalateDr.Aldrin Jerry

Development of TongueFormation of Anterior 2/3rd of the TongueFormation of Posterior 1/3rd of the TongueDevelopmental defect of TongueDevelopment of MandibleFormation of mandible

Development Of MaxillaFormation of maxillaDevelopment of TMJ

Developmental defect of maxilla and mandible

Dr.Aldrin Jerry

INTRODUCTIONDr.Aldrin Jerry

Development? Process of maturation

All naturally occurring unidirectional changes in the life of an individual from its existence as a single cell to its elaboration as a multifunctional unit terminating to death.Dr.Aldrin Jerry

Growth : Increase in size Entire series of sequential anatomic & physiologic changes taking place from the beginning of prenatal life to senility.

Embryology is defined as the study of growth and differentiation which an organism undergo during its development from a single fertilized cell to a complex independent living being [text book of Maji Jose,ORAL BIOLOGY ]. Embryology is the study of the development of an individual before birth [text book of Inderbir Singh G P Pal,HUMAN EMBRYOLOGY]5

Developing Oral cavity

(text book of Ten Cates,7th edition,ORAL HISTOLOGY)

Stomatodeum delimited by, frontal prominence-rostrally & cardiac bulge-caudally

Buccopharyngeal membrane breaks down & communicate directly with foregut

Laterally stomatodeum limited by the first pair of pharyngeal arch forms in the pharyngeal wall result of proliferating mesoderm and reinforcement by migrating neural crest cells

Dr.Aldrin Jerry

Around the 4th week of intra-uterine life formation of the head and tail folds the foregut is bounded ventrally by the pericardium and dorsally by the developing brain. The developing Oral cavity, stomatodeum is situated between the developing brain and pericardium which is open to the exterior.

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THE PHARYNGEAL ARCH or BRANCHIAL ARCH

6 cylindrical thickenings forms(5,6 transient)That expand from lateral wall of pharynx to their anatomical counterpartSeparates primitive stomatodeum from developing heart.(text book of Ten Cates,7th edition,ORAL HISTOLOGY)

Dr.Aldrin Jerry

Around the 4th week of intra-uterine life formation of the head and tail folds the foregut is bounded ventrally by the pericardium and dorsally by the developing brain. The developing Oral cavity, stomatodeum is situated between the developing brain and pericardium which is open to the exterior.

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Pharyngeal Apparatus include:

-Pharyngeal pouches (endoderm) - Branchial grooves (ectoderm)

(text book of Maji Jose,ORAL BIOLOGY )

Dr.Aldrin Jerry

Pharyngeal pouches inner aspect of pharyngeal wall (endoderm) coressponds to small depression called pharyngeal pouches- Pharyngeal clefts lateral aspect (ectoderm)of embryo seperated by small clefts called branchial clefts

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ARCHGROOVEPOUCHFirst1.Mandible and Maxilla2.Meckles cartilagea.Incus and malleus of inner earb.Sphenomalleolar ligamentc.Sphenomandibular ligament1.External auditory meatus2.Tympanic membrane3.Tympanic cavity4.Mastiod antrum5.Eustachian tubeSecond1.Reicherts cartilage:a.Styloid process of temporal boneb.Styloid ligamentc.Lesser horns of hyoid boned.Upper part of the body of the hyoid boneObliterated by down growth of the second arch1.Largely Obliterated2.Contributes to tonsilThird1.Lower part of the body of the hyoid bone2.Greater horns of the hyoid boneInferior parathyroid gland ThymusFourth1.Cartilage of the larynxSuperior parathyroid glandUltimobranchial bodyFifth & SixthTransientTransientTransient

Derivatives of Branchial Arch systemDr.Aldrin Jerry

ARCHNERVEINTERVENTION OF BLOOD VESSELSFIRSTMandibular(and maxillary) division of the trigeminal nerve(v)First aortic archSECONDFacial(vii)Second aortic archTHIRDGlossopharyngeal(ix)Third aortic archFOURTH vagusFourth aortic arch

Dr.Aldrin Jerry

Inetrventiuon and vascularization10

DERIVATIVES OF SKELETAL ELEMENTS:

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Early Oro-Facial development

From 1st pharyngeal arch Fronto Nasal Process,Maxillary Process,Mandibular process

Dr.Aldrin Jerry

The Maxillary Process : The mandibular arches of both sides form the lateral walls of the stomadeum. The mandibular arch gives off a bud from its dorsal end called the maxillary process. The Mandibular Process : The maxillary process grows ventro-medial-cranial to the main part of the mandibular arch which is now called the mandibular process.

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(text book of Ten Cates,7th edition,ORAL HISTOLOGY)

Early Oro-Facial development

Dr.Aldrin Jerry

Olfactory pacodes-rapid proliferation of mesenchyme-horse shoe shaped ridge-nasal pit-lateral & medial arm of horse shoe is lateral nasal process & medial nasal process13

Time table of events described in this seminarTongue formation begins at 4th week of embryo

Palate formation begins 5th week of embryo

Mandible 6th week of embryo

Maxilla 7th week of embryoDr.Aldrin Jerry

Tongue formation begins at 4th week of gestation and ends by 8th weekPalate formation begins 5th to 9th weeks of embryo

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DEVELOPMENT OF PALATE

Dr.Aldrin Jerry

What is Palate?The palate is the tissue that interposes between the oral & nasal cavities it develops from two parts

The Primary PalateThe Secondary Palate

Development of palate 5 to 9 weeks of embryo.

(text book of Ten Cates,7th edition,ORAL HISTOLOGY)

Dr.Aldrin Jerry

It is basically formed by 3 elements, Premaxilla Two Lateral Palatal

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Development Of The Primary Palate :

Fusion of the two medial process with the fronto nasal process results in the formation of primary palate.Dr.Aldrin Jerry

and is derived from the fronto nasal process. The merging of the two medial nasal process results in the formation of that part of maxilla carrying the incisors and the primary palate and part of the lip.17

Development of Secondary Palate:

The formation of secondary palate commences between 7 and 8 weeks and completes around the 3rd month of the gestation. Three outgrowth appear in the oral cavityThe two palatal processThe nasal septum

Dr.Aldrin Jerry

The primitive palate formed by the fronto nasal process

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(text book of Ten Cates,7th edition,ORAL HISTOLOGY)

-Each palatal process grows downwards first then upwards after the withdrawal of tongue(7th week)

-septum and the two shelves converges and fuse in the midline

Dr.Aldrin Jerry

(text book of Ten Cates,7th edition,ORAL HISTOLOGY)

-The closure of the secondary palate proceeds gradually form the primary palate in a posterior direction.

-Epithelial seam formed by the adhesion of palatine shelves is lost due to growth of palate and form ectomesenchymal continuity Dr.Aldrin Jerry

The part of the palate derived from the frontonasal process forms the premaxilla, which carries the incisor teeth.20

Hard Palate and Soft Palate:

-Intra-membranous : Conversion of mesenchymal connective tissue, usually in membranous sheaths, directly into osseous tissue is known as intramembranous ossification. Hard palate:At later stage, the mesoderm in the palate undergoes intra membranous ossification to form the hard palate.Soft palate: However ossification does not extend in to the most posterior portion, which remains as the soft palate.

Dr.Aldrin Jerry

Intramembranous bone formation begins as the area destined to become bone becomes highly vascularized and the mesenchymal cells develop into osteoblasts. These bone-forming cells then begin secreting collagen and a matrix composed of mucoproteins, constituting the osteoid. These osteoblasts possess long cell processes that communicate with other osteoblasts and nearby blood vessels. At this stage, the osteoid is a rubbery, tough, somewhat elastic material as yet uncalcified.Mineral ions of calcium and phosphate, circulating in the blood, begin to diffuse into osteoid tissue and are deposited on the surfaces of collagen fibers as fine crystals. This imparts a hardness and rigidity to the osteoid in the process of becoming bone. Osteoblasts (cells that were responsible for secreting the matrix) become trapped in lacunae and are now renamed osteocytes.

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Developmental defect of palateDr.Aldrin Jerry

(borrowed from http://www.scielo.br/scielo.php?pid=S1678-77572012000100003&script=sci_arttext)

Dr.Aldrin Jerry

Syndromes associated with cleft palate:Treacher-Collins syndromePierre-Robin AnomaladDowns syndrome

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DEVELOPMENT OF TONGUE

What is Tongue? Largest single muscular organ inside the oral cavity, which lies relatively free. Tongue develops in relation to the pharyngeal arches.

It develops from two parts, they are

formation of anterior 2/3rd of the tongueformation of posterior 1/3rd of the tongueDr.Aldrin Jerry

Formation of anterior 2/3rd of the tongue:

Tuberculum Impar: first a swelling arises in the midline of the mandibular process. And is flanked by two other swellings

Lingual Swelling: The lateral part of the mandibular process mesenchymal thickening develops to form two lingual swellings.

Swellings merges with each other and forms the mucous membrane of ant 2/3rd of the tongue

(text book of Inderbir Singh ,8th edition,G P Pal,HUMAN EMBRYOLOGY)

Dr.Aldrin Jerry

5th cranial nerve-trigeminal-first arch[according to some the tuberculum impar does not make a significant contribution to the tongue]26

Formation of anterior 2/3rd of the tongue:

These lateral swelling quickly enlarge and merge with each other and the tuberculum impar to form a large mass from which mucous membrane of the anterior 2/3rd of the tongue is formed.

Ant 2/3rd is supplied by Trigeminal nerve

(text book of Inderbir Singh ,8th edition,G P Pal,HUMAN EMBRYOLOGY)

Dr.Aldrin Jerry

5th cranial nerve-trigeminal-first arch

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Formation of posterior 1/3rd of the tongue:

Root of the tongue arises from large midline swelling develops from mesenchyme of 2nd,3rd and 4th arches. Consist of ,

Copula (associated with 2nd arch)

A large hypobranchial eminence (associated by 3,4th acrh)(text book of Inderbir Singh,8th edition, G P Pal,HUMAN EMBRYOLOGY)

Dr.Aldrin Jerry

9th cranial nerve-glossopharyngeal-3rd arch28

Hypobranchial eminence overgrows the copula

The tongue separates from the floor of the mouth by a down-growth of ectoderm around its periphery, which degenerates to form lingual sulcus and gives the tongue mobility.

Post 1/3rd is supplied by glossopharyngeal nerve

(text book of Maji Jose,1st edition,ORAL BIOLOGY)Dr.Aldrin Jerry

4th arch vagus29

Muscle of the tongue have a different origin, they arises from the occipital somites, which have migrated forward in to the tongue area, carrying with them their nerve supply hypoglossal nerve

(text book of Ten Cates,7th edition,ORAL HISTOLOGY)

Dr.Aldrin Jerry

12th cranial nerve30

Taste Bud;A specialized receptor that occurs only in the oral cavity and pharynx is called taste bud.

Most of them found in fungiform papilla, foliate and circumvallate papilla.

Barrel shaped structure composed of 30 to 80 spindle shaped cells

Communicate with surface through a small opening called taste pore

Cells divided in to type1(light), type2(dark), type3(intermediate)Dr.Aldrin Jerry

Taste stimuli:

Generated by the adsorption of molecules on to the membrane receptors on the surface of the taste bud cells, which activates a signaling cascade mediated by membrane associated proteins such as transucin and gustducin.

The change in membrane polarization that follows stimulate release of transmitter substances, which in turn stimulate unmyelinated afferent fibers of the glossopharyngeal nerve that surrounds the lower half of the taste bud.Dr.Aldrin Jerry

Papillae:Small nipple or hair-like structure on the upper surface of the tongue that give the tongue its characteristics rough texture.

Types:Fungiform PapillaeFilliform PapillaeFoliate PapillaeCircumvallate PapillaeDr.Aldrin Jerry

Fungiform Papillae:Anterior portion of the tongue (look like fungi)

Scattered between the numerous filifom papillae at the tip of the tongue

Smooth, round structure appears red(because of highly vascular connective tissue core, visible through a thin, non keratinized covering epithellium) Dr.Aldrin Jerry

Filiform Papillae:covers entire anterior part of the tongue

Cone shaped structures each with a core of connective tissue covered by a thick keratinized epithelium

Together form a tough abrasive surface that is involving in compressing and breaking food when tongue is opposed to the hard palate

The dorsal mucosa of the tongue function as masticatory mucosa

Buildup of keratin results in elongation of the filiform papillae.The dorsum of the tongue then has a hairy appearance called hairy tongueDr.Aldrin Jerry

Foliate papillae:

Sometimes present on the lateral margins of the posterior part of the tongue

Pink,consist of 4 to 11 parallel ridges that alternate with deep grooves in the mucosa and few taste buds are present in the epithelium of the lateral walls of the ridgesDr.Aldrin Jerry

Cirumvallate Papillae:Adjacent and Anterior to the sulcus terminalis are 8 to 12 papillaeLarge structure, each surrounded by a deep, circular groove in to which open the duct of minor salivary glandHave connective tissue core that covered on the superior surface by a keratinized epitheliumThe epithelium covering lateral walls is non-keratinized and contains taste buds Dr.Aldrin Jerry

Developmental Defect of Tongue:Macroglossia: Tongue size is too large

Microglossia: Tongue size is too small

Borrowed from:http://www.google.co.in/imgres?imgurl=http%3A%2F%2Fjournal.nzma.org.nz%2Fjournal%2F120-1254%2F2534%2Fcontent01.jpg&imgrefurl=https%3A%2F%2Flookfordiagnosis.com%2Fmesh_info.php%3Fterm%3Dmacroglossia%26lang%3D1&h=177&w=249&tbnid=iKaj-oyWpYADSM%3A&zoom=1&docid=yh9x9MIyw9y7BM&ei=ikT8U7DiEMWzuATYnYGQBw&tbm=isch&ved=0CDMQMygEMAQ&iact=rc&uact=3&dur=1058&page=1&start=0&ndsp=19Borrowed from:httphttp://www.google.co.in/imgres?imgurl=http%3A%2F%2Fi.ytimg.com%2Fvi%2FV6RJFa1tHxI%2F0.jpg&imgrefurl=http%3A%2F%2Fwww.digplanet.com%2Fwiki%2FDevelopmental_abnormality&h=360&w=480&tbnid=fBd6vT6NEAMpJM%3A&zoom=1&docid=YbklHsbJG1OYPM&ei=10T8U6GjGdefugTV4YL4Bg&tbm=isch&ved=0CDYQMygHMAc&iact=rc&uact=3&dur=1107&page=1&start=0&ndsp=12Dr.Aldrin Jerry

Aglossia: tongue is absent

Bifid tongue:non fusion of the two lingual swellings

Borrowed from:http://www.google.co.in/imgres?imgurl=http%3A%2F%2Fwww.jomfp.in%2Farticles%2F2012%2F16%2F3%2Fimages%2FJOralMaxillofacPathol_2012_16_3_414_102504_f1.jpg&imgrefurl=http%3A%2F%2Fwww.jomfp.in%2Farticle.asp%3Fissn%3D0973-029X%3Byear%3D2012%3Bvolume%3D16%3Bissue%3D3%3Bspage%3D414%3Bepage%3D419%3Baulast%3DGupta&h=617&w=853&tbnid=HPfeqELMHRKcgM%3A&zoom=1&docid=9FTHmvCMTDOOcM&ei=FUX8U8rTK4eOuASwjoCYBw&tbm=isch&ved=0CC8QMygAMAA&iact=rc&uact=3&dur=1217&page=1&start=0&ndsp=12Borrowed from :http://www.google.co.in/imgres?imgurl=http%3A%2F%2Felementsofmorphology.nih.gov%2Fimages%2Fterms%2FTongue%2CBifid-large.jpg&imgrefurl=http%3A%2F%2Felementsofmorphology.nih.gov%2Findex.cgi%3Ftid%3D1af98064c7272d0a&h=288&w=400&tbnid=ml1x-GH6yfNCrM%3A&zoom=1&docid=Lk_wDI0Ll0_FBM&ei=dEX8U4v7EZSTuATXtoHQBg&tbm=isch&ved=0CC8QMygAMAA&iact=rc&uact=3&dur=1850&page=1&start=0&ndsp=12Dr.Aldrin Jerry

Ankyloglossia or tongue-tie: The apical part of the tongue attached to the floor of the mouth.

Ankyloglossia Superior: Occasinally rare condition, the tongue may be adherent to the palate.

Borrowed from:http://www.google.co.in/imgres?imgurl=http%3A%2F%2Fwww.ghorayeb.com%2Ffiles%2FAnkyloglossia_2_SQ.jpg&imgrefurl=http%3A%2F%2Fwww.ghorayeb.com%2FTongueTie.html&h=420&w=420&tbnid=h4-_2ekIaym7dM%3A&zoom=1&docid=FcxDUV5AY-FqPM&ei=pUX8U7y0OsW2uASXw4CYBw&tbm=isch&ved=0CDAQMygBMAE&iact=rc&uact=3&dur=728&page=1&start=0&ndsp=12Dr.Aldrin Jerry

A red rombhoid shaped smooth zone may be present on the tongue in front of the foramen caecum. It is considered to be the result of persistence to the tuberculum impar.

The surface of the tongue may show fissures.

(Text book of Shafers ORAL PATHOLOGY,7th edition)(Text book of Shafers ORAL PATHOLOGY,7th edition)

Dr.Aldrin Jerry

Development of Mandible

Dr.Aldrin Jerry

Dr.Aldrin Jerry

Formed by both intramembranous and cartilaginous

Body and ramus are derived from intramembranous ossification

Coronoid process, condylar process and mental process develop from cartilage

Dr.Aldrin Jerry

On the lateral aspect of Meckels cartilage during 6th week, a condensation of mesenchyme appears.

At 7 weeks, intramembranous ossification starts.

The two cartilages do not meet at the midline but are separated by a thin line of cartilage symphysis

Forms lateral and medial plate

Dr.Aldrin Jerry

On the lateral aspect of this symphysis a condensation of mesenchyme forms

At 7 weeks intramembranous ossification begins in this mesenchyme and spreads anteriorly and posteriorly to form the bone of the mandible

Dr.Aldrin Jerry

Then spreads anteriorly to the midline of the developing lower jaw the bones do not fuse at the midline mandibular symphysis forms (from meckels cartilage)

Which fuses shortly after birth

The ramus develops from rapid ossification posteriorly into the mesenchyme of the first arch diverging away from meckels cartilage. This point of divergence is marked by the mandibular foramen.

Dr.Aldrin Jerry

Secondary cartilage: condylar,coronoid,symphyseal

Wedge-shaped nucleus in the condylar process and extending downward through the ramus.

Small strip along the anterior border of the coronoid process.Dr.Aldrin Jerry

The condylar cartilage appears in the region of the condyle and occupies most of the developing ramus. It is rapidly converted to bone by endochondral ossification (14th. WIU) it gives rise to: -Condyle head and neck of the mandible.The posterior half of the ramus to the level of inferior dental foramen.

Dr.Aldrin Jerry

Development of Maxilla

Dr.Aldrin Jerry

Develops from centre of ossification in the mesenchyme of maxillary process of 1st arch.

No arch cartilage is formed, but associated closely with cartilage of nasal capsule.

Bone formation spreads, Ant- to future incisors Post-below the orbit towards developing zygoma Superiorly-frontal process

Dr.Aldrin Jerry

Due to ossification a boney trough is forms for infra orbital nerve.

From this trough a downward extension of bone forms lateral alveolar plate in relation to tooth germs.

Spreads palatine to form hard palate.

Medial alveolar plate is formed by the junction of palatal process and main body of maxilla.

Trough of bone which formed aroung the tooth germ enclosed by boney crypt.

Secondary Cartilage: zygomatic or malar cartilage.

Dr.Aldrin Jerry

Development of TMJ Dr.Aldrin Jerry

TMJ:Articulation between two bones(temporal and mandible)

Temporal blastema-dev from otic capsule of basicranium.

Condylar blastema- dev from Secondary cartilage.

Before the dev of Condylar process, broadband of undifferentiated mesenchyme exsits between developing ramus of mandible and squamous of tympanic bone.

Later condylar cartilage is formed.Dr.Aldrin Jerry

Mesenchyme reduced rapidly in width due to dev of condylar process.

Converted to dense strip of mesenchyme.

Mesenchyme immediately adjacent to strip breaks down forms joint cavity.

Strip forms articular disk.Dr.Aldrin Jerry

Developmental Defect of maxilla and mandible

Dr.Aldrin Jerry

Micrognathia Small jaw size

Agnathia Total failure of development

Microstomia Excess fusion of the maxillary and mandibular processes may result in microstomia.

Macrostomia Inadequate fusion of the maxillary and mandibular processes with each other may lead to an abnormally wide mouth. Lack of fusion may be unilateral leading to lateral facial cleft.

Dr.Aldrin Jerry

Micr- Associated with pierre-robin syndromeMacro-Treacher-Collins syndromeMicro-Pierre Robin syndrome

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Oblique Facial Clefts failure of maxillary prominence to fuse corresponding lateral nasal processes.

Midline mandibular cleft -Persistance of furrow between 2 mandibular prominences -Rare condition

Dr.Aldrin Jerry

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Treacher-Collins Syndrome (mandibulofacial dyostosis)

1)Abnormal external, middle and inner ear2)Malar and mandibular hypoplasia3)Lower eyelid defectsDr.Aldrin Jerry

Full facial development does not occur because neural crest cells fail to migrate properly to the facial region.

FEATURESFace is bird or fish likeHypoplasia of facial bones,esp of malar bones and mandibleMalformation of external earMacrostomiaHigh PalateAnti mongoloid palpebral fissuresOther anomalies like facial clefts and skeletal deformities

Dr.Aldrin Jerry

Pierre Robin Syndrome

1)Mandibular hypoplasia2)Cleft palate3)Eye and ear defects

Dr.Aldrin Jerry

Thank You

Dr.Aldrin Jerry