ORTHO Flashcards
HOW intramembraneous ossification happens?what cells?
osteoblast forms bone directly within loose fibrous CT
WHEN endochrondral ossification is initiated and HOW [from… framework with help of] and what pattern/what happens?
after birth and from hyaline cartilage framework ; with help of chrondroblast instead of osteoblast [IMo], woven bone formed and remodelling happens
where is primary growth centre for Endochrondral ossification? what is Synchondrosis?
1* growth centre with lengthing of base of skull [synchrondrosis]. Synchondrosis is a type of joint where bones are connected by hyaline cartilage. This joint is typically immovable or allows very limited movement. A common example is the epiphyseal plate (growth plate) in children, which eventually ossifies and becomes a solid bone as they grow.
Growth direction of IMossification?
displacement [remodelling] result in forward and downward translation of maxilla
neural vs somatic growth
growth determined by growth of brain vs genetic control
Dentoalveolar compensation
development of alveolar arches so that the teeth ->secure occlusion and maintain normal inter-arch rslhp to varying basal parts of jaw [form of adaptation]
direction of growth for max and mandible
max: dwnward and 4wd [IMo] ; Md also dwnward and 4wd [Endochrondrial ossif. - condyles]
factors affect timing and sequence of eruption- 7x
1Craniofacial syndromes - CLeido-cranial dysplasia +DS+ ectodermal dysplasia; 2
2 dental anomalies-gemination/supernumerary[lack of space]-
3 hypodontia-Ectodermal dysp/ primary failure of eruption,
4 delayed exfoliation in gemination/infraoccl
5 dental trauma affect in development-abn shape/dilaceration;
6 localised issue-eg Fibrous tissue overlying erupting tooth
7 premature birth+ malnutrition-> vit D def-> rickets [soft bones] /hypothyroidism
incisor liability
difference between amount of space needed for lower incisors and amount available for them;max usually sufficient space
primate spacce
mesial to UC’s ; distal to LC’s
spaces to compensate for ‘…..’ via 4x eg
incisal liability is the space discrepancy that occurs when larger permanent incisors replace smaller primary incisors. The maxillary arch typically has a 7 mm discrepancy, while the mandibular arch has a 6 mm discrepancy.
4 egs primate space, proclination, inc in intercanine distance, leeway space [md> max]
andrews 6 keys
CI molar [MB cusp-> MB groove]+ [DBcusp to MB cusp]; 2. Correct angulation [m-d tip] ; correct crown inclination [b-l direction/torque]; 4. no rotation, 5 no spaces, 6 flat occl plane
TSALD
tooth size arch length discrepancy - crowding/spacing
hand wrist xray - what to see?
Epiphyseal Plates: -stage of their closure can signal remaining growth potential.
Sesamoid Bone of the Thumb: The appearance and development of the sesamoid bone near the metacarpophalangeal joint of the thumb are another maturity indicator.
