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71 terms

Developmental Disturbances

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What separates primary and secondary ossification centers?
Epiphyseal growth plates (made of hyaline cartilage)
In mature bone, where is the cartilage found?
on the ends
What must first be present for endochondral ossification to occur?
must have hyaline cartilage first
What is the first type of bone to be made?
woven bone
Woven bone becomes either
compact bone or spongy bone
Outer lining of bone
periosteum
Osteoblasts are found
on the periphery of bone in periosteum's inner layer
Osteoclasts are found
within bone mass, enclosed in intercellular material
Intercellular material of bone
ground substance, fibrous matrix and hydroxyapatite
Primary osteon is
smooth, formed initially when bone is laid down
Secondary osteon is
jagged, found when remodeling occurring, after initial bone laid down
Remodeling of bone requires
resorption and deposition
Remodeling of bone is a
normal daily process
Arrest lines
deposition during remodeling, osteoblasts rest and stay in a perfect line. process of bone being laid down
Reversal lines
resorption and deposition; osteoclasts resorb to have osteoblasts deposit. rough and jagged
Primary ossification occurs in
the center of the bone
Secondary ossification occurs
on the ends of bone
Microdontia
alteration in size, teeth appear small. usually single tooth (max laterals, 3rd molars and supernumerary teeth)
True generalized microdontia
rare, whole dentition small
Relative generalized microdontia
teeth appear small due to large bone
Macrodontia
alteration in size, teeth appear big. usually single tooth (mand 3rd molars)
True generalized macrodontia
rare, whole dentition big
Relative generalized macrodontia
teeth appear big due to small bone
Gemination
alteration in shape, attempt of single tooth to form 2 teeth. more common in deciduous and occurs when no teeth missing
Tooth germ
not completely formed tooth
Fusion
alteration in shape, union of 2 normally separated teeth. occurs if tooth missing
Concrescence
type of fusion that occurs after root formation. fusion of root to bone
Dilaceration
alteration in shape, abnormal curve in the root or crown of a tooth
Flexion
type of dilaceration, abnormal curve in just the root
Dens In Dente / Invaginatus
alteration in shape, invagination of enamel into surface of tooth's crown. a tooth within a tooth
Dens Evaginatus
alteration in shape, proliferation of enamel during development. extra enamel in wrong spot, may be on root. usually on max laterals and canines. "enamel pearl"
Taurodontism
alteration in shape, crown/body of tooth is enlarged at expense of roots. large pulp chambers, short roots. "bull like" teeth
Supernumerary roots
alteration in shape, extra root(s)
Anodontia
alteration in number, lack of teeth
True Anodontia / Congenital Total
missing all teeth
True Partial Anodontia or Hypodontia
one or more teeth are congenitally missing. usually 3rd molars
Supernumerary teeth
alteration in number, extra teeth, most often in maxillary. erupt facially on max and lingually on mand
Mesiodens
type of supernumerary teeth, most common and found between max centrals
Distomolars
2nd most common type of supernumerary teeth, found distal to max 3rd molars
Paramolar
type of supernumerary teeth, molar between max molars
Predeciduous Dentition
alteration in number, teeth prior to normal deciduous teeth
Natal teeth
prematurely erupted TRUE deciduous teeth at time of birth, do NOT extract, usually mand centrals
Neonatal teeth
hornified epithelial structure w/ no roots, false teeth, erupt w/ in days of birth, DO extract. exhibit poor anatomy
Post permanent Dentition
alteration in number, 2nd set of permanent teeth
3 stages of normal enamel development
1. Formative stage 2. Calcification stage 3. Maturation stage
Formative stage
deposition of organic matrix, initially soft tissue
Calcification stage
matrix becomes mineralized (hydroxyapatite)
Maturation stage
crystals enlarge, thicken and mature
What percentage of enamel is calcified?
96%
Problems could occur during which stages of enamel development?
during any of the 3 stages
Ameloblasts form
enamel
Enamel dysplasia or hypoplasia
problem with development of enamel, not enough enamel
Hypoplastic
type of enamel dysplasia; defective formation of enamel matrix, thin enamel. occurs during formative stage
Hypocalcification
type of enamel dysplasia; hypomineralization, defective mineralization of formed matrix. occurs during calcification stage
Hypomaturation
type of enamel dysplasia; enamel crystals remain immature. occurs during maturation stage
Environmental Causes of enamel hypoplasia
1. Nutrional deficiency/exanthematous diseases 2. Congenital syphilis 3. Hypocalcemia 4. Birth injuries 5. Local infection or Trauma 6. Ingestion of Chemicals 7. Idiopathic factors (unknown)
Congenital syphilis results in
Hutchinson teeth - teeth w/ notches or mulberry molar -tiny additional cusps
Inherited amelogenesis imperfecta
loss of enamel on selected teeth or whole mouth, genetic
Dentinal dysplasia
defect in dentin
Tetracycline staining
intrinsic color change to dentin undergoing mineralization. yellow to grayish to purple
Hereditary dentinogenesis imperfecta
bluish brown color or yellow, pulp chamber may be missing, enamel is normal but fractures easily due to dentin malformation
Regional odontodysplasia
etiology unknown, very large pulp chamber, ghost teeth appearance, nonfunctional teeth
Odontoblasts lay down
dentin
Premature eruption
natal (true) teeth
Eruption sequestrum
spicule of bone overlying crown of erupting permanent molar
Embedded teeth
lack of eruptive force (max canine)
Impacted teeth
due to physical barrier, tooth coming in wrong direction. impacted permanent teeth may become ankylosed
Ankylosed deciduous teeth
submerged teeth, ankylosed to adjacent tooth's bone, "pink crown"
Odontomas
benign tumors, growth of calcified dental tissue (ectodermal and mesodermal - CT and epithelial)
Complex odontomas
one mass of calcified dental tissue, no definite dental form appearance, more of a mass
Compound odontomas
calcified dental tissues arranged in appearance more like a tooth