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67 Cards in this Set
- Front
- Back
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Growth vs Development
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Growth - Increase in size & Number
Development - Increase in organization or complexity - Closely related, but not synonymous |
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Growth pattern pre and post natal
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Fetal head is 50%
Birth head is 30% Adult head is 15% More growth of lower limbs than upper limbs during post natal life reflecting Cephalocaudal gradient of growth. |
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Three possibilities for growth
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Hypertrophy - Increase in Size
Hyperplasia - Increase in number Secretion of ECM - important in skeletal system |
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Interstitial vs Appositional growth
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Interstitial - Found in nearly all soft tissue and uncalcified cartilage. Growth in length
Appositional growth - Mineralization on the surface occurs so that hard tissue is formed. Deposition of new bone by cells in periosteum. Increased bone width. |
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Intramembranous bone formation
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Formation by direct secretion of bone matrix
- Predominant mecanism in skull Undifferentiated mesenchymal cells can become osteoblasts to deposit first fibrous bone matrix called Osteoid & mineralization occurs almost immediately. - Some osteoblasts continue to secrete bone matrix, others become surrounded by their own deposits and become osteocytes. |
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Endochondral bone formation
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Bone begins as cartilaginous matrix surrounded by perichondrium except at ends
- Long bones associated with movable joints - Mandibular condyle - Bones of cranial base - Middle ear ossicles Hypertrophy of chondrocytes occur in primary ossification center, and blood vessels from pericondrium erode into mineralized are and brings in vessels carrying sheath of undifferentiated mesenchymal tissue. Some cells become osteoblasts to form bone. |
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Bone remodeling
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Asspositional growth at periosteal surface and resorption at endosteal surface.
Drift Displacement Relocation |
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Vital staining
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Ingest certain chemicals which are incorporated into developing bone.
Alizarin sulfonate - chelates with inorganic portion of bone Procion - Organic phase of bone Tetracycline - absorbed by mineralizing tissues and will fluoresce under UV light |
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Radioisotopes
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Injected into living test animals and become incorporated into bone undergoing growth or remodeling.
- Ca45 - P32 - Proline H3, found in hydroxyproline component of developing collagen fibers of osteoid matrix |
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Implants
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Titianium pellets implanted into the facial area as radio-opaque reference points for cephalometric analysis. Compare between first and succeding xrays
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Comparative anatomy
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Study of other species and infer information to humans
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Cephalometrics
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Used in ortho to aid in diagnosis and treatment planning. Indicates relative amt and direction of craniofacial growth in 2 dimensions
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Natural markers
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Examine persistence of developmental features such as trabeculae and lines of arrested growth
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3 theories on determinants of craniofacial growth
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Bone is primary determinant
Cartilage is and bone responds secondarily and passively Soft tissue matrix is, and both bone & cartilage are secondary When bone responds passively, its called Epigenetic. First theory has largely been tossed |
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Sicher's theory
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- Growth of skull is controlled mainly by intrinsic genetic factors
- Only surface remodeling is influenced by local environmental factors such as muscle forces - paired parallel sutures push nasomaxillary complex downard to match mandiblular growth |
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Scott's nasal septal theory
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- Intrinsic genetic factors operate only on cartilage and periosteum and cartilaginous parts of skull are centers of growth with nasal septum as the major contributor/pacemaker of maxillary growth.
- Thus, Craniofacial growth is coordinated because sutural growth is responsive to growth of synchondroses. |
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Enlow's V principle
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Many facial & Cranial bones have V shape and deposition occurs on inner side whereas resorption occurs on other side.
Overall increase in dimensions |
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Moss's Functional Matrix theory
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No intrinsic genetic growth mechanism in skull
- Growth depends on bony components of skull is determined by growth and function of other factors such as muscles, tongue, eyes, brain etc. |
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Van Limborgh's theory
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Mixes others
- Growth and ossification of skull parts is controlled by intrinsic genetic factors - Therefore follows a path and cannot be affected - Desmocranium and structures adjacent to head is a source of epigenetic influences - Extent of influences from epigenetic factors depends on intensity of influences |
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2 primary components of cranium
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Desmocranium - earliest mesenchymal precursor to cranial vault. Develops via intramembranous. Starts 1st month in utero, occipital first then parietal & frontal
Chondrocranium - Embryonic cartilaginous cranium. Develops via endochondral |
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Calvaria bone growth
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Thickens with age due to deposition on both periosteal & meningeal surfaces
- Medullary endosteal sorfaces are resorptive |
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Fontanelles & Closures
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Fibrous tissue membranes that exist at angles of parietal bone to allow skull to pass through birth & accomodate brain.
6 total Anterior Posterior 2 Sphenoid 2 mastoid Sphenoid & Posterior close at 2-3 months, Mastoid at 12mths, Anterior at 18months - Cranial growth occurs through 7yr which is when cranial vault reaches adult dimensions |
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Sutures
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Metopic of frontal suture
Saggital suture Labdoid suture Coronal suture Squamous suture |
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Craniofacial synostosis
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Premature fusion of 1 or more cranial sutures/fontanelles
Scaphocephaly - Saggital suture Anterio plagiocephaly - one coronal suture Brachycephaly - both coronal sutures Posterior plagiocephaly - one lambdoid suture Trigonocephaly - early fusion of metopic suture |
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Crouzon syndrome
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- Most common craniofacial syndrome
- Skull is typically brachycephalic with prominent nose & protruding jaw - Exopthalmos - Hydrocephalus |
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Apert syndrome
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- Second most common syndrome after Crouzon
- High brachycephaly and severe syndactyly - Clefts of soft palate & uvula are often. - Hands and feet show bony fusion |
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Development of Chondrocranium
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Limited to cranial base starting at second month in utero starting first at occipital plate.
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Major portion of increased length and age of growth
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Major portion of increased length occurs at cartilaginous joints between ethmoid, sphenoid & occipital bones.
Continues till 18-25 |
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Development of maxilla
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Arise as 2 separate bones and begins intramembranous ossification at 6th wk.
Growth occurs 2 ways: Apposition of bone at sutures that connect maxilla to cranium & Surface remodeling |
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Embryo development
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7 Processes
1 Median nasal process 2 Lateral Nasal process 2 Maxillary and 2 Mandibular processes all from first branchial arch |
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Formation of the Palate
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Occurs 5-6week
- Fusion of median nasal process gives rise to upper lip, anterior part of alveolar process of maxilla, & anterior portion of palate Secondary Palate - Fusion of palatine shelves of maxillary process forms incisive foramen |
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Cleft lip & Palate
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Cleft lip 4-7 week
- Failure of fusion of medial nasal & Maxillary processes usually on left. Cleft palate 6-10 wks - Failure of palatine shevesl of maxillaru process to fuse |
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Cephalometric radiograph & age determination
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Analysis of cervical vertebrae 2-4 will show visible concavity at lower border of C3 immediately preceding peak in mandibular growth. Will occur 1 year after this stage.
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Variations in eruption sequence with clinical significance
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Eruption of mandibular 2nd molars ahead of premolars can block 2nd premolar out of arch
Eruption of Maxillary canines ahead of premolars can force canine out labially If permanent tooth on one side erupts but counterpart does not within 6 months, should take radiograph to investigate |
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Variation in Suckling & Swallowing
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Infant - Active contraction of lips with little activity of posterior tongue or pharyngeal muscles.
Adult - Lips relaxed, posterior teeth into contact |
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Variation in mastication
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Child - mandible moves laterally during opening then back to midline on closing. Pattern transition in conjunction of permanent canine eruption
Adult - Mandible opens straight down then moves jaw laterally to bring teeth into contact |
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Speech variations
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1st sounds - Bilabial p, b
Tongue tip - t, d Sibilant - s, z Tongue tip close but not against palate Last speech sound - r 4-5 |
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Stages of adolescence in girls
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I - Beginning: Breast buds & Early pubic hair
II - 1 yr after: Peak velocity III - 1-1.5yr after stage 2: Menstruation, broadening of hips with adult fat distribution. |
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Stages of adolescence in boys
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I: Fat spurt: Increase in size & pigmentation change in scrotum
II: 1 yr after: Pubic hair, penis growth III: 8-12 months after peak velocity, upper lip hair, muscle IV: 14-24 mths after: Spurt complete, facial hair, |
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Growth of nasomaxillary complex
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1) Passive displacement - growth in cranial base pushes maxilla forward. Important during primary dentition years
2) Active growth of maxillary structures and nose. Downward and forward growth of maxilla |
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Mandibular growth
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Ramus hight 1-2mm/yr
Body length 2-3mm/yr Increase in chin prominence - variable due to glenoid fossa growth |
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Timing of growth in width length and height
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Width first then length and then height
- Maxillary down and forward growth complete at 14-15. 2-3yrs after 1st menstruation |
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Bjork
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Internal rotation - Rotation that occurs at core of each jaw
External rotation - Surface changes and alterations in the rate of tooth eruption Total - Internal - External rotation |
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Maxillary jaw rotation
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Core rotates slightly forward internal
Bone resorption on nasal side & apposition on palatal side is external Cancel each other out |
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Short face type
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Excessive forward rotation of mandible - too much internal rotation
- Deep bite & crowded incisors. Brachycephalic |
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Long face type
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Porsterior downard rotation of palatal plane.
Decrease internal rotation of mandible and increase mandibular plane angle Anterior open bite & mand deficiency. Dolicocephalic |
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Facial growth in adults
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Vertical>AP>Width
Male: Forward rotation tendency to decrease mandibular plane angle Female: Backward rotation tendency for increase mandibular plane angle |
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Edward H. Angle's beliefs & Paradigm shift
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Maxillary first molars were key to occlusion
Shift: - Greater emphasis on dental and facial appearance - Patients are more involved in planning their treatment - Older patients being treated require multidisciplinary approach |
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Normal overjet & Overbite
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Normal overjet: 2-3mm
Normal overbite: 1-2mm |
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% of children falling into angle's 4 groups
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30% Normal
50-55% Class I 15% Class II <1% Class III |
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Prevalence of Malocclusion
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African Americans likely to have diastema & open bite
Whites have more severe deep bites and more class II Asians have more class 3 Hispanics have more severe class 3 but less vertical problems |
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Primate Spaces
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Maxilla: Lateral to canine
Mandible: Canine & First molars |
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Development of occlusion
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Birth - 6months: Edentulous
6 month-2yr: Eruption of primary 2yr-6yr : Full primary 6-12yr: Mixed dentition |
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When does permanent teeth erupt? & desired sequence
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Begins at 6 and when 3/4 of root is formed
7154632 7165432 |
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Eruption steps
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Preemergent eruption
- Resorption of bone(Rate limiting) & resorption of primary roots - Eruption mechanism itself then moves where path was cleared Eruption movement then occurs after root formation. This supports idea that PDL metabolic activity plays major role |
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Cleidocranial dysplasia
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Can have failure of bone resorption leading to failure of eruption
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Postemergent eruption
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Once tooth emerges, erupts rapidly till it approaches occlusal level
- Mostly occurs between 8pm & 1am possibly related to circadian rhythm - Following this stage is juvenile occlusal equilibration where teeth in function erupt at a rate that parallels vertical growth of ramus |
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Measurement of adequate spacing
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Spaced arch - Baume type I
Non spaced arch - Baume Type II |
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Leeway space of Nance
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Sum of CDE is greater than space for 345.
Averages 1.5mm/side in maxilla & 2.5mm/side in mandible |
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Early mesial shift
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Close primate and interdental spaces before E is lost
Eruptive force of first permanent molars causes mesial migration of mandibular primary molar into mandibular primate space. Changes terminal plane into a mesial step |
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Late mesial shift
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When mandibular permanent molar moves mesially into leeway space upon loss of mandibular second molar
- If permanent molars are edge to edge, late mesial shift allows mand molar to move into Class I after loss of E - However, arch length is reduced |
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Incisor liability
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When centrals erupt, they take up essentially all of that space
- Just enough space in maxilla - Mandible has 1.6mm less space than needed - Transitory period of mand incisor crowding at age 8-9 |
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Arch length
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Distance between line tangent to labial surface of central incisors and line connecting dorsal pts on distals of 2nd primary molar or 2nd premolar
- Decreases, increases, decreases again |
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Arch width
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Distances between tips of canine, lingual cusp of premolars, & ML cusps of primary and permanent first molars
Increases throughout with a 3-5mm net increase |
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Arch circumference
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Length of curved line passing over buccal cusps or incisal adge from distal surface of 2nd primary molar of 2nd premolar
Slight increase throughout |
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Overbite
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Distance which maxillary incisal edge closes vertically past mandibular incisal edge during occlusion
Ideal - 10-15% |
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Mixed Dentition space analysis
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Moyer's prediction chart or Tanaka & Johnson method
Measure space available and subtract total space required - Negative is crowding, positive is space |
