Interceptive Orthodontics Flashcards
sequence of eruption of deciduous teeth
a, b, d, c, e
primate space
spaces mesial to upper canines and distal to lower
natal/ neonatal teeth
tooth/teeth present at or just after birth , most commonly lower incisors
may need to be extracted if they are mobile and presenting a risk of inhalation or interfering with breast feeding
what are the 3 phases of tooth eruption
pre eruptive
eruptive
post eruptive
compare the deciduous dentition to permanent dentition
incisors are more upright in the deciduous dentition
deciduous more spaced
deciduous experience lots of wear, centrals often edge to edge by time of exfoliation due to wear
pre eruptive phase of tooth eruption
timing and what occurs
starts when crown begins to form and ends when crown formation is complete/ root formation about to begin
developing crowns move constantly with the jaws and reposition themseves in response to increasing length, width and height of the jaws.
during the pre eruptive phase what is the movement of tooth crowns contained within
bony crypts
eruptive phase of tooth eruption
timings and stages
starts as soon as root begins to form and ends when teeth reach the occlusal plane
split into intra osseous stage and extra osseous stage
what 3 things can movement of tooth crowns occur in response to
positional changes of neighbouring crowns
growth of mandible and maxilla
resorption of deciduous tooth roots
how does root formation occur
starts with proliferation of the epithelial root sheath and continues with the production of dentine and pulp
occurs during the intra osseous stage of the eruptive phase of tooth eruption
what occurs within the dental follicle during the intra osseous stage of tooth eruption
degeneration. blood vessels decrease in number, nerve fibres break up into pieces and the resulting area is known as the eruption pathway. On the periphery of this pathway fibres known as gubernacular cord are formed
gubernacular cord
formed around the eruption pathway from the degeneration of the dental follicle
theory is that this cord guides teeth to erupt in the oral cavity
when does the intra osseus stage of the eruptive phase end
when the reduced enamel epithelium fuses with the oral epithelium to form junctional epithelium right before the crown breaks the surface.
extra osseuous stage of tooth eruption
begins as soon as tip of tooth crown is through epithelial layers - a fast process, only 1-2 weeks
continues as crown moves through mucosa until it contacts the opposing tooth - a slow process , takes several months
what environmental factors influence tooth positioning during the extra osseous stage
tongue, cheeks, lips, muscles
post eruptive phase of tooth eruption
tooth movement and eruption continues as the root forms and throughout life in extremely small increments
movement occurs in response to increases in height of alveolar bone, attrition and abrasion and loss of opposing teeth
cause of tooth eruption is multifactorial , name 3 things thought to contribute
root formation
remodelling of alveolar bone
development of periodontal ligament
dental follicle
how is the dental follicle said to influence tooth eruption
has a key role in modulating cellular activity , it is believed signalling takes place between dental follicle and reduced enamel epithelium and tooth eruption is controlled by a signalling cascade of cytokines including RANKL and interleukin 1
how does the dental follicle promote tooth eruption
(not gub cord or eruption pathway)
initiates resorption of bone overlying the tooth
facilitates connective tissue degradation and creates the eruption pathway
promotes alveolar bone growth at base of tooth
provides traction forces within PDL
interceptive orthodontics
any procedure that will reduce or eliminate the severity of a developing malocclusion
in relation to the primary teeth where to permanent teeth develop
palatal/ lingual
if a planned extraction of a primary tooth is required what is the ideal stage of the permanent succesor if we want to encourage eruption
when the root is 1/2 to 2/3 developed
name 3 ways in which space is gained to accomodate the larger mesiodistal width of permanent teeth in comparison to primary teeth
increase in intercanine width through lateral growth of the jaws
upper incisors erupt onto a wider arc as they are more proclines
leeway space
leeway space
difference in space between the width of primary canine and molars and incoming permanent canines and pre molars
in upper arch this gains about 1-1.5mm and in lower arch 2-2.5mm is gained
ugly duckling phase
occurs in children around 8 years old
roots of laterals are being pressed upon by developing canines making laterals, and possibly centrals, splay distally. this will usually sort itself out
within what timeframe are contralateral teeth on the same jaw expected to erupt
within 6 months
