Interceptive Orthodontics

Question 1

sequence of eruption of deciduous teeth

Answer 1

a, b, d, c, e

Question 2

primate space

Answer 2

spaces mesial to upper canines and distal to lower

Question 3

natal/ neonatal teeth

Answer 3

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

Question 4

what are the 3 phases of tooth eruption

Answer 4

pre eruptive
eruptive
post eruptive

Question 5

compare the deciduous dentition to permanent dentition

Answer 5

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

Question 6

pre eruptive phase of tooth eruption
timing and what occurs

Answer 6

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.

Question 7

during the pre eruptive phase what is the movement of tooth crowns contained within

Answer 7

bony crypts

Question 8

eruptive phase of tooth eruption
timings and stages

Answer 8

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

Question 9

what 3 things can movement of tooth crowns occur in response to

Answer 9

positional changes of neighbouring crowns
growth of mandible and maxilla
resorption of deciduous tooth roots

Question 10

how does root formation occur

Answer 10

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

Question 11

what occurs within the dental follicle during the intra osseous stage of tooth eruption

Answer 11

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

Question 12

gubernacular cord

Answer 12

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

Question 13

when does the intra osseus stage of the eruptive phase end

Answer 13

when the reduced enamel epithelium fuses with the oral epithelium to form junctional epithelium right before the crown breaks the surface.

Question 14

extra osseuous stage of tooth eruption

Answer 14

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

Question 15

what environmental factors influence tooth positioning during the extra osseous stage

Answer 15

tongue, cheeks, lips, muscles

Question 16

post eruptive phase of tooth eruption

Answer 16

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

Question 17

cause of tooth eruption is multifactorial , name 3 things thought to contribute

Answer 17

root formation
remodelling of alveolar bone
development of periodontal ligament
dental follicle

Question 18

how is the dental follicle said to influence tooth eruption

Answer 18

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

Question 19

how does the dental follicle promote tooth eruption

(not gub cord or eruption pathway)

Answer 19

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

Question 20

interceptive orthodontics

Answer 20

any procedure that will reduce or eliminate the severity of a developing malocclusion

Question 21

in relation to the primary teeth where to permanent teeth develop

Answer 21

palatal/ lingual

Question 22

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

Answer 22

when the root is 1/2 to 2/3 developed

Question 23

name 3 ways in which space is gained to accomodate the larger mesiodistal width of permanent teeth in comparison to primary teeth

Answer 23

increase in intercanine width through lateral growth of the jaws
upper incisors erupt onto a wider arc as they are more proclines
leeway space

Question 24

leeway space

Answer 24

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

Question 25

ugly duckling phase

Answer 25

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

Question 26

within what timeframe are contralateral teeth on the same jaw expected to erupt

Answer 26

within 6 months