Growth and Development of Nasomaxillary complex
INDIAN DENTAL ACADEMY
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Source: JCO on CD-ROM (Copyright © 1998 JCO, Inc.), Volume 1983 Oct(669 - 679): JCO/lnterviews: Dr. Donald H. Enlow on Craniofacial Growth
DR. GOTTLIEBIs there good growth and bad growth? DR. ENLOW Well, no. Growth for any individual is "normal",
given the circumstances that exist for that individual. Growth is a process striving toward a state of functional equilibrium, and it is always responsive to the conditions that occur, unless pathology is involved. Most structural dysplasias, of course, are in "equilibrium".
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Growth and development of Nasomaxillary complex
Anatomy Pre natal growth Post natal growth Theories Nasomaxillary remodeling Clinical implications Articles Summary
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Area of Nasomaxillary Complex
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AnatomySkeletal Tissues / Bones• Maxilla• Zygomatic• Palatine• Lacrimal• Vomer• Nasal spine, septum• Ethmoid• Sphenoid
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AnatomySinuses
• Maxillary• Frontal• Ethmoid• Sphenoid• Nasal cavity
Radiological appearance
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Anatomy
• External anatomy of the nose• Muscles attachments• Blood supply• Nerve supply• Lymphatic• Histological features• Relation to surrounding structures
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Anatomy Of Maxilla Two maxillae articulate to form
1. Whole upper jaw.2. Roof of oral cavity.3. Greater part of buccal roof, floor and
lateral wall of nasal cavity and part of nasal bridge.
4. Greater part of floor of the orbit.5. Infratemporal and ptergyopalatine
fossae6. Inferior orbital and pterygomaxillary
fissures
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Anatomy Of Maxilla Parts of Maxilla
1. Body –Large and pyramidal in shape .
2. Four processesFRONTAL
ZYGOMATICALVEOLARPALATINE
MAXILLA HOUSES THE LARGEST SINUS OF THE FACE THE MAXILLARY SINUS
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Palatine process[maxilla]
Maxillary sinus
Frontal process
Maxillary process [palatine]
Alveolar process
Maxilla – Medial View
Horizontal plate of palatine
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Nasal notch
Zygomatic process
ANS
Alveolar process
Maxilla - Lateral View
Frontal process
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Maxilla
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Anatomy Of Maxilla1. nasal 2. frontal 3. ethmoid 4. sphenoid 5. maxilla 6. horizontal process of
palatine 7. superior concha
(ethmoid) 8. middle concha (ethmoid) 9. inferior concha 10. sphenopalatine foramen 11. medial pterygoid plate 12. pterygoid hamulus of
medial plate
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Anatomy Of Maxilla
At birth Adultwww.indiandentalacademy.com
Palatine bone
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Palatine Bone
Horizontal platePerpendicular platePyramidal processOrbital processSphenoidal process
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Zygomatic BoneCheek prominenceLateral wall of orbitInfratemporal fossa3 Foramen3 MusclesFrontal process – lateral palpebral, suspensory ligament.Temporal process
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Zygomatic Bone
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Lacrimal Bone
Smallest – most fragileArticulates with
Maxilla Frontal
boneEthmoid
boneNasal
concha
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Nasal SeptumThe nasal septum is made up of the following: perpendicular plate of ethmoid vomer maxilla septal cartilage Muscles attached to Nasal bones – Procerus and nasalis.
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Vomer
TrapezoidPosterior part of
nasal septum
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EthmoidLateral masses with air cells ossified at birthNasal septum part ossifies during 1styrCribriform laminae ossify in 2nd yrCrista galli between 2nd &4thyrThese cartilages fuse with the lateral masses in the 6thyr
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SphenoidThree parts
BodyLesser wingGreater wing
with the pterygoid processes fuse during the 1st yrSpheno-occipital synchondrosis begins after puberty
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External nose• Covered by the integument, and lined by
mucous membrane • The bony frame-work occupies the upper part of
the organ; it consists of the nasal bones, and the frontal processes of the maxillæ.
• The cartilaginous frame-work (cartilagines nasi) consists of five large pieces cartilage of the septum, two lateral and the two greater alar cartilages, and several smaller pieces, lesser alar cartilages
The cartilage of the septum (cartilago septi nasi) is quadrilateral termed the septum mobile nasi. www.indiandentalacademy.com
External nose
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External nose
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Para nasal Sinuses
Maxillary sinusFrontal sinus
Ethmoidal sinusSphenoidal sinus
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Maxillary sinusPyramidal shaped Base - lateral wall of the nasal cavityApex - into the zygomatic processAverage - 14.75ccFloor of sinus is above that of nasal cavity at birthSinus increases 3times ant-post & 5times in height and widthIn the inferior end of the uncinate process, is the ostium maxillare, or opening from the maxillary sinus
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Frontal sinus• The Frontal Sinuses (sinus frontales)• Behind the superciliary arches• Average measurements are as follows:• Height, 3 cm• Breadth, 2.5 cm• Depth from before backward, 2.5 cm• Opens into middle meatus of the nose
through the frontonasal duct • Absent at birth, they are generally fairly
well developed between the seventh and eighth years
• Reach their full size after pubertywww.indiandentalacademy.com
Ethmoidal sinusThe Ethmoidal Air Cells (cellulae ethmoidales)Ethmoidal labyrinth and completed by the frontal, maxilla, lacrimal, sphenoidal, and palatine bonesThree groups, anterior, middle, and posteriorThe anterior and middle groups open into the middle meatus of the noseThe posterior cells open into the superior meatus Develop during fetal life.
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Sphenoidal sinus• The Sphenoidal Sinuses (sinus
sphenoidales)• Average measurements• Vertical height, 2.2 cm• Transverse breadth, 2 cm• Antero-posterior depth, 2.2 cm• Communicates with the
sphenoethmoidal recess • Minute cavities at birth• Development takes place after puberty
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Nasal CavityThe nasal chambers are situated one on either side of the median planeThey open in front through the nares, and communicate behind through the choanæ with the nasal part of the pharynxNares are somewhat pear-shaped apertures, each measuring about 2.5 cm - antero-posteriorly and 1.25 cm - transversely at its widest part Choanae are two oval openings each measuring 2.5 cm. in the vertical, and 1.25 cm. in the transverse direction in a well-developed adult skull
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Radiological appearance
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Indices• Cephalic index• Total facial index• Upper facial index• Nasal index• Orbital index• Palatal index• Gnathic index
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Para nasal Sinuses
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Relations with surrounding tissues
• Infratemporal fossa• Ptergyopalatine fossa• Basicranium• Middle ear• Oral cavity• Nasopharynx
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Muscle attachments
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Blood vessels, Nerves & Lymphatics
External carotid arteryV & VII cranial nerveSubmandibular lymphnodes
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Histological Appearance
Olfactory cells, olfactory hairs and glands of Bowman, are identical in structure with serous glands The epithelial cells of the nose, fauces and respiratory passages play an important role in the maintenance of an equable temperature
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Development of Embryo
• 1st week – 3rd week• Ovum Zygote Blastocyst Gastrula
Neurulation
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Development of Embryo 4th weekSomitesNeural tube formation24th day 1st and 2nd arch are
distinct26th day – 3 pairs of
branchial arches otic pits appear 4th pair of branchial arches and lens placodes are visible
• C shaped curvature of the embryo
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Branchial Arches 1st Arch - Mandibular Arch• 2 prominences - mandibular prominence
- maxillary prominence• Bones – mandibular,
maxilla, zygomatic squamous part of the temporal bonemalleusincus
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Branchial Arches 1st Arch - Mandibular Arch• Muscles of mastication• Mylohyoid and anterior belly of digastric• Tensor tympani• Tensor veli palatine Anterior ligament of malleus Sphenomandibular ligament Trigeminal nerve except the opthalmic
division Maxillary artery Meckel’s cartilage
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Branchial Arches2nd Arch - Hyoid Arch• Bone - hyoid
stapes styloid process lesser cornu of hyoid upper part of body of
hyoidwww.indiandentalacademy.com
Branchial Arches 2nd Arch - Hyoid Arch• Muscles of facial expression
stapedius stylohyoidposterior belly of digastricstylohyoid ligament
Facial nerve Stapedial artery Reichert’s cartilage
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Branchial Arches Third Arch• Bone – greater cornu and the inferior
part of the body of the hyoid bone• Stylopharyngeus Glossopharyngeal nerve Common carotid artery Internal carotid artery Carotid body
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Branchial Arches Fourth Arch• Thyroid cartilage
corniculatecunieform cartilage
• Muscles – cricothyroid, constrictors of pharynx, palatopharyngeus, uvular muscles of soft palate, palatoglossus
Superior laryngeal nerve Left – arch of aorta & Right –
subclavian and brachiocephalic arteries
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Branchial Arches Sixth arch• Cricoid cartilage
arytenoid cartilage• Recurrent laryngeal nerve
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Pre natal growth and development
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Prenatal embryology
• Face - Upper - Frontonasal - Middle - Maxillary - Lower - Mandibular
Organizing centersProsencephalic - Upper third of faceRhombencephalic - Middle third of
face
1/3rd Prominence
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4th week IUL
• Shallow depression - Primitive mouth - Stomodeum
• Floor of the stomodeum is formed by the Buccopharyengeal membrane
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Pre-natal growth At fourth week of of IUL- 1.migration of neural crest cells 2.formation of brachial arches
STOMODEUM
FRONTONASAL MAXILLARYMAXILLARY
MANDIBULAR MANDIBULARwww.indiandentalacademy.com
Medial nasal process
Lateral nasal process
Maxillary process
Mandibular process
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Maxillary and Mandibular processes-
first branchial arch Frontonasal processes- downward
proliferation of mesenchyme of developing brainMedial nasal Lateral nasal
Mesenchyme of first arch
maxilla
palatine
mandible
zygomatic
Part of temporalwww.indiandentalacademy.com
Nasal process
Median nasal
process
Lateral nasal
process
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At Seventh Week IUL- 1.Formation of upper lip 2.Intramembranous Bone
ossification Takes Place 3.Formation of Nasal Septum 4.Nasolacrimal Duct 5.Formation of Primary Palate
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At Seventh Week IUL Primary ossification center -for
each maxilla at termination of infraorbital nerve above canine tooth dental lamina.
Secondary centerzygomaticorbitonasal
intermaxillarynasopalatine
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At Eighth Week IUL Two intermaxillary ossification centers
generate the alveolar ridge and primary palate
Intramembranous ossification centers appear for;
-Nasal and lacrimal bones.-Medial pterygoid plate of sphenoid.-Vomer.-Zygomatic bone
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Anteroposterior maxillo- mandibular relationship approaches that of newborn infant
Maxilla increases in height
Twelfth Week
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Growth of palate
1st trimester-narrow 2nd trimester-moderate width 3rd trimester- wide Breadth>length Height changes less dramatic
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Growth of palate
• Two primordia, primary palate and secondary palate
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Pre-natal Growth and development of palate
Formation of primary and secondary palate
Elevation of palatal shelves
Fusion of palatal shelves
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Early palate formation 28th day of IUL -disintegration of buccopharangeal
membrane stomadeal chamber
Horizontal extensions
Oral cavity
Nasal cavity
2 palatal shelves
Single primary palatewww.indiandentalacademy.com
Structure of palate
PALATOGENESIS
Secondary palatePrimary palate
5 TH week IUL
12 TH week IUL
6 9
CRITICAL PERIODwww.indiandentalacademy.com
Primary palateFrontonasal process
Medial nasal
Mesenchyme
Wedge shaped mass between internal surface of maxillary prominence
Primary palatePre-maxilla
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Primary palate
Primary palate
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Secondary palate
2 horizontal mesenchymal projections
Maxillary prominence
Lateral palatine process
Fuse-With each otherPrimary palateNasal septum
Secondary palatewww.indiandentalacademy.com
Secondary palate
Palatal Shelveswww.indiandentalacademy.com
Elevation of palatal shelves At 6 weeks1. Tongue {undifferentiated tissue} pushes dorsally2. palatal shelves become vertical3. Elevation occurs from vertical to
horizontal position
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Elevation of palate
Nasal septum
Palatal shelves
Tongue
Histological section
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At 8 weeks
Elevation of palatal shelves
Muscular movement
Pressure differences
Biomechanical transformation
Intrinsic shelf force
Differential mitotic growth
Withdrawal of embryo’s face
Vascular changes
Increase in tissue turger
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Elevation of head and lower jaw
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Fusion of palatal shelves
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Fusion of palate
Incisive foramen
Mid palatine raphe
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Formation of palate [summary]Primordiu
m ofFormed by
Derived from
Primary palate
Secondary
palate
Pre maxill
a
Hard and soft
palate
Median palatine process
Lateral palatine process
Frontonasal process
Maxillary process
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Ossification of the palate• Premaxillary centres• Primary ossification centres of
each palatine bone• Y shaped midpalatal suture• T shaped midpalatal suture• No ossification at the soft palate
region
8th wk
10th wk
Childhood
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Musculature of palate
Tensor veli palatini 40 days 1st arch Palatopharangeous 45 days Levator veli palatini 8th week 2nd
arch Palatoglossus 9th week Uvular muscle 11thweek 2nd
arch
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Growth in dimensions
Length - 7-8 weeks IUL Width - 4th month onwards
heightwidthlength
Arched palate
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Growth in dimensions Pre natal life (appositional growth in the alveolar
margin)
length > width
At birth (appositional growth in the maxillary tuberosity)
length = width
Post natal life width > lengthwww.indiandentalacademy.com
Factors affecting growth of palate
Elevation of head and lower jaw Oxygen and nutritional deficiency Excess endocrine substances Drugs Irradiation Vascularity
teratogens
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Maxillary sinus PRE NATAL lateral evagination of mucous
membrane in middle meatus –3rd month IUL
AT BIRTH 2mm -long, 1mm in width +
height PNEUMATISATION
PRIMARY SECONDARYwww.indiandentalacademy.com
Neonatal Skull
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Cleft Lip and Palate
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Genesis of cleft lip and palate Associated with more than 150
syndromes Aetiology• Mutant gene or chromosomal
aberrations - Monogenic - Polygenic
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Etiology of cleft lip / palate
Infectious agents
Irradiation
Drugs
Nutritional deficiency
Excess hormones
Smoking and alcohol
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• Separation due to wide growing brain and cranial floor
• Separation due to tongue• Biochemical or tissue barrier
intercedes between the fusing parts
• Primary failure in the fusion
Genesis of cleft
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Cleft lip usually seen at the philtrum and the lateral part of the upper lip
Harelip
Bifid nose
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Prenatal anomalies
Formation of germ layers
Day 17
Fetal alcohol syndrome[mid face deficiency]Migration
and proliferation of cell population
Day 19-28
Treacher Collin syndrome
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Prenatal anomalies
Primary palate formation
28-38 days
Cleft lip /cleft palate other facial clefts
Secondary palate formation
42-55 days
Cleft palate/synostosis Crouzon syndromeEpithelial pearlsTorus palatinusHigh arched palatewww.indiandentalacademy.com
Other syndromes• Downs syndrome• Hurlers syndrome• Cebocephaly• Scaphocephaly• Apert syndrome• Cyclops• Van der Woude syndrome• Craniostenosis
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ANOMALIES OF PALATE Epithelial pearls
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ANOMALIES OF PALATE
Torus palatinus
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ANOMALIES OF THE PALATE
High arched palate
MARFANS SYNDROME CROUZON
SYNDROMECLEIDOCRANIAL DYSOSTOSIS
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Genesis of cleft palate Delay in shelf elevation Disturbance in
mechanism of shelf elevation
Failure of shelves to contact due to lack of growth
Failure to displace the tongue during closure [Pierre Robin syndrome]
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ANOMALIES OF PALATE Cleft palate
Failure of fusion of the lateral palatine process with each other or with the median palatine processwww.indiandentalacademy.com
Genesis of cleft palate Failure to fuse
after contact as epithelium does not break down
Rupture after fusion
Defective merging www.indiandentalacademy.com
Types of cleft palate
Bifid uvula
Unilateral cleft palate
Bilateral cleft palatewww.indiandentalacademy.com
Bilateral cleft palate
Bifid uvula
Unilateral cleft palate
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Classifications Davis and Ritchie’s : (1922)
Group I – prealveolar clefts
Group II – postalveolar clefts : cleft involving hard and soft
palate
Group III – Cleft of both primary and secondary palate
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Veau’s classification : (1931)
A. Cleft lip
class I : U/L notching of vermillion border, not extending into the lip.
class II : cleft extending into the lip, but not including the floor of the nose.
class III: extending into the floor of the nose.
class IV: any b/l cleft of the lip, whether incomplete or complete.
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• B. Cleft palate
• class I : soft palate
• class II : soft/hard palate extending no further than incisive foramen
• class III: complete u/l cleft, extending from uvula to incisive foramen, then
deviating to one side
• class IV: two clefts extending forward from the incisive foramen into the alveolus
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Fogh Anderson’s Classification (1946)
1. Hare lip cleft
2. Hare lip cleft associated with cleft palate
3. Isolated cleft palate
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Kernahan / Stark’s (1958)
1. Cleft of primary palate
2. Cleft of secondary palate
3. Cleft involving both primary and secondary palate.
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Interdisciplinary approach• Genecist• Orthodontist• Oral Maxillofacial Surgeon• Prosthodontist• Plastic Surgeon• Paediatrician • Social workers• Psychiatrist / Psychologist • Speech Pathologist / Therapist• Audiologist• Nursing serviceswww.indiandentalacademy.com
Stage I
• Maxillary Orthopedic stage – Birth to 18 months
• Mc Neil – 1950 prosthetic devices• Obturator
False plateMaxillary cross arch stabilityMaxillary orthopedic molding
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• Premaxillary orthopaedics – birth to 5 months
• 1686 – Hofman• Use of headcap and premaxillary
strap to reposition the premaxilla
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• Cheiloplasty• Rule of Tens
10 weeks of age10 pounds of body weight10 grams of hemoglobin
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• Maxillary orthopaedics – 3 to 9 months
Obturator to provide cross arch stability
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Stage II - Primary dentition - 18 months to 5 yrs
Stage III - Late primary or mixed dentition – 6 to 11 yrs
Stage IV – Permanent dentition – 12 to 18yrs
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Grafting procedures• Palatoplasty - 1 to 2 yrs• Primary bone grafting < 2 yrs• Early secondary bone grafting – 2 to 4 yrs• Secondary bone grafting – 6 to 15 yrs• Late secondary bone grafting – Adult
• Graft from RIB - 2cms is harvested
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Clinical features of cleft palate
Feeding problems particularly in infants in whom suckling process demands intact palate
Nasal regurgitation/nasal twang in voice
Collapsed arch
Difficulty in speech and swallowingwww.indiandentalacademy.com
Dental deformities• Natal or neonatal teeth• Congenitally missing teeth• Supernumerary teeth• Ectopic eruptions• Altered tooth morphology• Deficient alveolar bone support• Rotations, deviations in axial root
inclinations• Posterior cross bite• Mobile and protuberant premaxilla• Convex profile
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Post natal growth of Nasomaxillary
complex
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• General features• Three dimensional growth of maxilla
Height (Vertical)Width (Transverse)Length (Ant-Post)
• Theories of growthSuturalCartilaginousFunctional matrix theory
• Key factors in Nasomaxillary remodelling www.indiandentalacademy.com
Displacement• Primary
displacement
• Secondary displacement
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Reversal line• Directions of growth
sequentially undergo reversals
• A reversal line showing the crossover between resorptive and depository growth fields seen in microscope
• Factors affecting reversalshape of bonemuscle attachmentsrotationsgrowthfeilds
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Post natal growth of maxilla Surface remodeling
Displacement
CRANIAL BASE MAXILLA
apposition
resorption
MOSS
Transformation
Translation
SUTURES
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Post natal growth of maxilla Mechanism of growth• Sutural • Nasal septum• Surface apposition and resorption on
periosteal and endosteal surfaces• Alveolar process • Spheno occipital synchondrosis
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• In contrast to cranial base maxilla is dominated by intra membranous ossification
• Endochondral bone growth seen at the ethmoid bone and nasal septum
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Surface apposition
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Spheno occipital synchondroses
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Post natal growth
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Post natal growth At Birth
Hard palate : length = widthmaxillary sinus : not visible radiographically
1 – 2 years
Extensive remodeling descent of palate /enlargement of nasal cavity
Mid palatine suture growth ceases
No synostosiswww.indiandentalacademy.com
Post natal growth
Mid palatine suture starts closing at 9- 10 years
RME Best done between 9-14 yrs
THE MIXED DENTITION YEARS
Growth in width of the dental arch anterior to the first molar
Ceases by 5-6 yrs
Inter canine width completed
12 yrs - females
18 yrs - males
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Post natal growth
The depository growth potential of the tuberosity allows for arch expansion by moving the teeth posteriorly into the area of bone deposition
Extensive scope for growth modification before adolscent growth spurt
THE MIXED DENTITION YEARS
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Post Natal Growth THE EARLY PERMANENT DENTITION YEARS
•Growth modification still possible in boys
•RME can still be tried till 12 -15 yrs
•>15 years complete closure[synostosis]
Orthognatic surgerywww.indiandentalacademy.com
Age changes All para nasal sinuses increase in
size Vertical height decreases
Vertical changes > AP > width Soft tissue changes > skeletal Nose growth continues till 25 years Inclination of palatal plane
increases[post downwards]
Alveolar process resorbed
Tooth loss
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Effects of Dentition and Occlusion
• Bimolar width in the 1st molar region correlates- Vertical growth of maxilla- Growth in the midpalatal suture- growth in height
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Effects of Dentition and Occlusion
• Maxilla drifts – 5mm forward in molar region (by adolscence)- 2.5mm in incisor region
• Shortening of the arch perimeter – associated with eruption of 2nd molar
• Initiation of eruption of 3rd molar occurs after the greatest shortening of length in the maxillary dental arch
• Shortening of anterior segment – mesial drift of teeth – crowding of ant segment – convergence and narrowing of the bone basewww.indiandentalacademy.com
Post natal growth of maxilla
Growth in height vertical
Growth in width transverse
Growth in length A - Pwww.indiandentalacademy.com
Vertical growth • Bjork and Skieller implant
studies - height increases because of sutural growth toward the frontal and zygomatic bones- appositional growth in the alveolar bone, floor of orbit, on hard palate and resorption on nasal floor
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HEIGHT
Deposition on the oral side
Resorption on the nasal side
ENLOW AND BANG ‘V’ PRINCIPLE
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V principle of Bang and Enlow
Entire ‘v’ shaped structure moves in a direction towards the wide end of the ‘v’
Remodeling of palate
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H EIGHT
APPOSITION IN THE ALVEOLAR PROCESS
ERUPTION OF TEETHwww.indiandentalacademy.com
Sagittal view
Coronal view
HEIGHT - V’ PRINCIPLE
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Primary
displacement
HEIGHT
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WIDTH Finished earlier in postnatal life
WIDTH GROWTH IN MID PALATINE SUTURE
REMODELING IN THE LATERAL SURFACE OF ALVEOLAR PROCESS
Mutual transverse rotations of maxillary halves give palate ‘u’ shape www.indiandentalacademy.com
WIDTH• This growth mimics the general
growth curve
• Mutual transverse rotation of the two maxillae results in more separation of the halves in the posterior than the anterior segment
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LENGTH Begins rapidly in the 2 nd year of life
Maxillary tuberosity
Palato maxillary suture
primary
secondary
displacement
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LENGTH• Resorption in the anterior region of
the maxilla• Maxilla rotates in relation to the
anterior cranial base• Bjork and Skieller implant studies
have shown that anterior surface is stable sagittally
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Timing
• Alveolar process – eruption of teeth• Overall height – along with
- Vertical growth of mandible- General body growth curve
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Compensatory mechanism• Narrow palate – alveolar process
compensates for width and heightDeep bite – Occ plane parallel to mandibular planeLong anterior surface – Steep occlusal plane
• Adaptive nature Class I molar relation though skeletally retrognathic
• Orthodontic correction totally dependent on the adaptive capacity of alveolar process remodelling
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Theories of growth
SUTURAL THEORY
CARTILAGENOUS THEORY
FUNCTIONAL MATRIX HYPOTHESIS
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Sutural Theory Sutures have innate
growth potential Push bones apart Oblique in nature Sliding effect Resultant thrust in
the anterior and inferior direction
Weinman & Sicher
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Sutural Theory
• Shortcomings- Bone tissue in not capable of growth in a
field that requires level of compression needed to produce a pushing type of displacement
- Suture is essentially a ‘tension’ adapted tissue
- Sutures do not have inbuilt growth potential
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Cartilagenous theory Nasal septum – innate growth potential
Thurst effect – septomaxillary ligament – growth in fields of compression
More of forward and downward force than vertical
Bone enlarges at the sutures in response to the tension created by displacement
Surgical removal of Nasal septum…
Scott
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Removal of nasal septum –mid face deficiency
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Cartilagenous theory
Shortcomings • Nasal septum functions to support the roof of the
nasal chamber• Doesn’t displace the palate by itself
Reasons• Source of maxillary displacement is multifactorial• Exptl studies merely show that groeth process
functions in its absence rather than in its presence
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Functional matrix hypothesis
Basal body Infraorbital
nerve
Orbital unit Eyeball
Nasal unit Septal cartilage
Alveolar unit Teeth
MossSKELETAL UNITS FUNCTIONAL MATRIX
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Functional matrix hypothesis
Height
Enlarging orofacial capsule
Remodelling changes in the orbit
Soft tissues give control signals to genic tissues
response seen in the hard tissue www.indiandentalacademy.com
The Counterpart Analysis
Growth of any given facial or cranial Growth of any given facial or cranial part relates specifically to other part relates specifically to other structural and geometric counterparts structural and geometric counterparts in the face and cranium” – Enlowin the face and cranium” – EnlowAs the cranial flexure decreases, the maxilla is translated or displaced forward and downward to give a more protrusive maxillary position.www.indiandentalacademy.com
The Nasomaxillary Complex Remodeling
• The Lacrimal Suture• The Maxillary tuberosity • Key ridge• Vertical drift of teeth• Nasal airway• Palatal remodelling• Downward maxillary displacement• Maxillary sutures• The Cheekbone and Zygomatic Arch• The paranasal sinuses• Orbital Growth
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Lacrimal bone• Bounded by sutural connective tissue• Undergoes remodelling rotation – medial superior
part remains with the nasal bridge, - inferior part moves outwardly with the ethmoidal sinuses
• Provides slippage of multiple bones along sutural interfaces ‘ perilacrimal sutural system’
• Maxilla slides downwards along its orbital contacts• Developmental gridlock would develop without this
system
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Maxillary tuberosity Established by the posterior
boundary of anterior cranial fossa Helps in posterior and horizontal
lengthening of archAnterior displacement= posterior lengthening
lateral widening downward deposition Contributes to maxillary sinus
enlargementwww.indiandentalacademy.com
Key ridgeVertical crest below the malar protuberence ‘muzzle’Reversal occurs at the key ridgePosterior - appositionAnterior - resorption
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Vertical drift of teeth• Vertical drift – significant intrinsic
growth factor• provides intramembranous bone
remodelling • Moves the tooth in its socket – usually
called extrusion• mesial drift well known process –
‘Vertical drift’ not a part of everyday vocubulary
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Nasal airwayLining surface of bony wall and floor
Resorptive(except olfactory fossae)
Downward relocation of palate
Lateral and anterior expansion
Downward cortical remodelling of entire anterior cranial floor & lateral and inferior depositions on ethmoidal conchae www.indiandentalacademy.com
Nasal airway Ethmoidal conchae - lateral + inferior
deposition- medial + superior resorption
Inter nasal septum- lengthens vertically at sutural junctions
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Palatal remodelling• V principle• Bone deposition on the inside of the
arch• Growth along the mid palatal suture• Grows inferiorly exchange of old
palate for new hard and soft tissues occurs
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Downward maxillary displacement
• Primary displacement of the ethmomaxillary complex inferiorly
• New bone is added at all sutures and these sutures accompany displacement produced by the soft tissues
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Downward maxillary displacement
• The balance of > or < growth in posterior and anterior maxilla is due to clockwise/counterclockwise rotatory displacement caused by downward and forward growth of the middle cranial fossa
• Nasomaxillary complex undergoes
compensatory remodelling rotation to sustain its position relative to the vertical reference line and to the neutral orbital axis
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Maxillary sutures• Sutures slide or slippage of bones along the
interface
• Remodelling and relinkage of the collagenous fiber connections within the sutural connective tissue causes the displacement process
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Cheek and zygomatic bone• Posterior side of malar protuberence within the
temporal fossa is depository• Cheek bone relocates posteriorly as it enlarges• Posterior relocation slows after dental arch
length is achieved during childhood• Zygomatic arch moves laterally by resorption
on the medial side• Zygoma and cheekbone complex are displaced
anteriorly and inferiorly in the same directions as the maxilla
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Zygomatic regionPosterior relocation
anterior
posteriorIncrease in height
frontozygomatic
Inferior border
Lateral growth
displacementZygomaticotemporal [anterior]Frontozygomatic [inferior]
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Maxillary sinusAge changesExpands - 2mm vertically 3mm A-P - every year> in size - resorption in walls + alveolus
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Maxillary sinus POST NATAL All internal
surfaces resorption
[expect medial]
Rapid continuous downward growth
close proximity to buccal maxillary teeth
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Orbital growth• Most of the lining roof and floor are depository• Lateral wall remodels by deposition and medial by
resorpition• i)Forward remodelling of the nasal and superior
orbital rim,• ii) backward remodelling of the inferior orbital rim and
the malar area • iii) downward remodelling of the premaxillary region• combine to produce rotation and alignment of the
midface and upper facial regions
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References Contemporary orthodontics - PROFFIT Principles and practice of orthodontics - GRABER Essentials of facial growth - ENLOW Craniofacial embryology - SPERBER The developing human - MOORE and PERSAUD Oral histology and embryology - TENCATE Handbook of orthodontics – MOYERS A Text Book of Oral Pathology – SHAFER, HINE,
LEVY JCO/lnterviews: Dr. Donald H. Enlow on
Craniofacial Growth Volume 1983 Oct (669 - 679)
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References Moyers – 3rd edition Dentistry for child and adolescent -
MAC DONALD Clinical pedodontics - FINN Color atlas of Embryology-
MOORE,PERSUAD Hand Book of Facial Growth-ENLOW Grays Anatomy – 38th Edition Previous Seminars By - Dr.Chatura
Hegde, Dr Ravi Tej, Dr.Harshavardhan Kidiyoor and Dr Jaya Kothari.
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Ability is what you’re capable of doing. Ability is what you’re capable of doing. Motivation determines what you do.Motivation determines what you do.Attitude determines how well you do Attitude determines how well you do
it.it. - Lou Holtz- Lou Holtz
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QUANTITATION OF MAXILLARY REMODELING
Uniform displacement of all 3 pts in vertical direction [downward displacement –0.3mm/year]
Horizontal direction posterior displacement of all 3 pts [however the displacement of PNS was greater than ANS and pt A ]
THE INCREASE IN LENGTH IS PRIMARILY BECAUSE OF GROWTH IN POSTERIOR BORDER
Sheldon Baumrind,Edward Korn
AJO JAN 1987
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