QUIZ 3 Eruption and Shedding Flashcards Preview

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Flashcards in QUIZ 3 Eruption and Shedding Deck (58)
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what are the 5 types of physiologic tooth movements?

  • preeruptive
  • eruptive
  • posteruptive
  • shedding
  • avulsion


what is preeruptive movement?

positioning of tooth germs prior to eruption


what is eruptive movement?

the movement of the tooth into functional occlusion


what is posteruptive movement?

movements in compensation for the growth of the jaws/wear.  meant to keep the tooth in occlusion


what is shedding movement?

the programmed loss of the primary teeth to make way for the permanent dentition


what is avulsion?

an extreme example of non physiologic tooth movement



___ is the main functional requirement for teeth, as most normal tooth movements are aimed at maintaining the teeth in ___

occlusion, occlusion


which permanent teeth have primary counterparts?

incisors, canines, and premolars


permanent teeth develop ___ to primary tooth germs


consider the successional laminae


the permanent teeth and primary tooth germs start in the same crypt, but eventually develop what?

their own separate crypt in the bone


in the development of permanent teeth, the dental lamina extends backwards to give rise to which permanent teeth?

the 1st, 2nd, and 3rd molars


the development of permanent and primary teeth cause a fair amount of ___.  as the mandible/maxilla grow, tooth germs have to ___

  • crowding
  • shift around


in preeruptive movement, primary teeth move into position for eruption, and then what happens to the developing permanent teeth?

they shift into an apical position where they have primary counterparts


describe the preeruptive movement of maxillary and mandibular molars

  • maxillary molars:
    • first, occlusal surface arrive distally, and then they shift down into place when there is room
  • mandibular molars:
    • follow preeruptive movement of the maxillary molars
    • these have a more mesial inclincation, which swing into occlusion when there is room (or not)


preeruptive movement of the maxillary molars is followed by ___

the mandibular molars


in what ways are movements of the tooth germ accomplished?

  1. the whole tooth germ moves 
  2. directional growth 


how does the tooth germ maintain its relative position as the jaw lengthens and grows in height?

the tooth germ moves either by the whole tooth germ moving or by directional growth


preeruptive movements take place in a bony crypt, and thus are associated with what?

bone resorption and/or deposition


___ movements position the tooth for eruption and occur as the tooth germ develops



___ movement results in an increase in length, while ___ growth results in an increase in height

  • bodily 
  • directional/eccentric


eruptive tooth movements are ___ or ___

axial or occlusal


the actual eruption of the primary tooth into the mouth is only the final stage.  much more behind the scenes work happens to ___

align the tooth properly


in primary eruptive tooth movement, fusion of the ___ with the ___ creates an epithelium lined channel through which the tooth emerges

  • oral epithelium
  • reduced enamel epithelium (REE)


the permanent successional tooth forms in a ___ under the primary tooth

second bony crypt


describe permanent eruptive tooth movement

  • permanent successional tooth forms in a second bony crypt under the primary tooth
  • a channel, called the gubernacular canal, develops between the alveolar bone around the primary tooth and the permanent tooth as it erupts
  • the permanent tooth erupts through the gubernacular canal


at what rate does the permanent tooth erupt?

  • intraosseous: 1-10 um/day
  • in canal: up to 75 um/day


what is the gubernacular canal?

  • a channel that develops between the alveolar bone around the primary tooth and permanent tooth as it erupts
  • it forms along the remnants of the dental lamina attached to the lamina propria (gubernacular cord)


what are the 4 theories of the forces that drive eruption?

  • bone remodeling theory
  • root growth theory
  • vascular pressure theory
  • cushion hammock theory


describe the bone remodeling theory of eruption

  • bone deposits under an erupting tooth propelling it outwards
  • problems:
    • removal of dental follicle = no bone remodeling and thus no eruption
    • replica "teeth" placed in an intact follicle still form an eruption pathway


describe the root growth theory of eruption

  • root formation pushes the tooth outwards
  • problems:
    • pushing against what?
    • not enough root to account for the movement to occlusal plane
    • if you cut off the roots, a tooth will still erupt