ORTHO mixed dentition

Question 1

at what age is the eruption of the first permanent tooth?

Answer 1

6 years old

Question 2

describe the path of eruption of central incisors?

Answer 2

upper 1s develop palatal to upper As

Question 3

what may happen to the upper 1s if the As are not exfoliated?

Answer 3

upper 1s are deflected palatally and may get caught behind the lower incisors

Question 4

describe the path of eruption of lateral incisors?

Answer 4

upper 2s develop palatal to upper 1s
as the upper 1s erupt, the 2s are freed and can then move labially to erupt adjacent to 1s

Question 5

when are all 4 incisors present?

Answer 5

8.5-9.5 years old

Question 6

why may transient spacing of upper 1s occur?

Answer 6

due to the close proximity of their roots to the erupting 2s and 3s

Question 7

when is a mixed dentition space analysis performed in orthodontics?

Answer 7

in quadrants that have deciduous teeth where laterals and 6s are present

Question 8

why is mixed dentition space analysis performed?

Answer 8

to determine whether there will be space for 4s and 5s to come in

Question 9

how much space is required in the lower arch to prevent crowding of permanent teeth?

Answer 9

21mm

Question 10

how much space is required in the upper arch to avoid crowding of the permanent teeth?

Answer 10

22mm

Question 11

what is used for the buccal segment space analysis?

Answer 11

calipers or a ruler

Question 12

what is the main cause of crown root dilaceration?

Answer 12

intrusion injury

Question 13

what is crown root dilaceration?

Answer 13

crown and root formation continues in different direction
it can occur at any part of the root

Question 14

what is general management for a root dilaceration?

Answer 14

extract and keep the space until pt is old enough for implants

Question 15

what are the different types of supernumerary teeth?

Answer 15

supplemental - exact copies of teeth (2s, premolars)
conical/ tuberculate - contain tooth material but dont look like teeth

Question 16

what would be treatment for a supplemental lower incisor causing crowding?

Answer 16

XLA

Question 17

where are supernumerary most commonly found?

Answer 17

pre maxilla

Question 18

where do you find mesiodens?

Answer 18

maxillary midline

Question 19

what teeth are normally peg shaped?

Answer 19

lateral incisors

Question 20

what problems do peg laterals bring?

Answer 20

causing spacing and problems with aesthetics
may be associated with an absent contra-lateral incisor (hypodontia)
increased risk of ectopic canines

Question 21

what is hypodontia?

Answer 21

congenital absence of one or more teeth (not including 8s)

Question 22

what teeth does hypodontia most commonly affect?

Answer 22

upper 2s
lower 5s
upper 5s

Question 23

what does hypodontia present with?

Answer 23

delayed exfoliation or deciduous teeth
or
delayed eruption of permanent teeth

Question 24

how does an eruption cyst present?o

Answer 24

blue mucosa overlying an unerupted tooth

Question 25

where do eruption cysts most commonly present?

Answer 25

over Es and 6s

Question 26

eruption cyst symptoms?

Answer 26

asymptomatic resolves as tooth erupts may get blood in mouth when it bursts

Question 27

what are impacted teeth?

Answer 27

deciduous or permanent teeth that fail to erupt fully can be partly erupted

Question 28

what causes impacted teeth?

Answer 28

an obstruction (supernumerary) primary failure of eruption insufficient space ectopic teeth (erupting/ forming in wrong position)

Question 29

what age do we assess position of upper 3s?

Answer 29

8 years +

Question 30

what is a good sign that canines wont be ectopic?

Answer 30

mobile Cs symmetry

Question 31

what incisor relationship are ectopic canines common in?

Answer 31

class II div II

Question 32

what are infra-occluded teeth?

Answer 32

often incorrectly called submerging usually due to ankylosis adjacent teeth erupt and ankylosed teeth remain unchanged vertically (gives appearance of submerging)

Question 33

what causes infra-occluded teeth?

Answer 33

no permanent successor idiopathic

Question 34

why should you not leave treatment for an infra-occluded tooth too late?

Answer 34

it may become subgingival and will need a surgical xla

Question 35

presentation of retained deciduous teeth?

Answer 35

normal

Question 36

cause of retained deciduous teeth?

Answer 36

missing permanent successor or ankylosis

Question 37

management of retained deciduous teeth?

Answer 37

XLA if due to ankylosis (because this could deflect permanent successor erupting) leave in-situ if missing permanent successor unless going below gingival level

Question 38

causes of premature loss of deciduous teeth?

Answer 38

caries balancing and compensating xla trauma

Question 39

what is the most frequent problem associated with early loss of deciduous teeth?

Answer 39

mesial drifting of 6s resulting in premolar crowding

Question 40

what can avulsion of a deciduous incisor lead to?

Answer 40

centre line shift in incisors delayed eruption of permanent incisor (due to fibrous mucosa)

Question 41

what is a balancing extraction?

Answer 41

if you take out a tooth on one side of arch may consider extracting the contra lateral tooth - if there is a concern of centre line shift during eruption of permanent incisor

Question 42

what teeth are commonly used for balancing xla?

Answer 42

Cs and Ds

Question 43

what is a compensating xla?

Answer 43

if extract one arch consider extracting the same tooth in the opposing arch

Question 44

what teeth are most commonly affected by crossbite?

Answer 44

incisors or molars

Question 45

what teeth are usually considered for compensating extractions?

Answer 45

6s - if you extract lower 6 can get over eruption of upper 6 which can cause occlusal interference *only consider extracting upper when lowers are gone

Question 46

what problems may occur with crossbite?

Answer 46

displacement - tooth and jaw tooth wear

Question 47

why may 1st permanent molars be extracted?

Answer 47

caries/ poor prognosis/ MIH

Question 48

what is the optimum age to extract 1st permanent molars?

Answer 48

9-10years old if you want the 7s to erupt well

Question 49

what problems occur with digit sucking?

Answer 49

proclined upper anteriors retroclined lower incisors buccal segment crossbites reduced overbite anterior open bite

Question 50

management for digit sucking?

Answer 50

deterrent devices/ habit breakers elastoplast on finger encouragement nail varnish

Question 51

aetiology of midline diastema?

Answer 51

98% of 6 year olds - normal dental development - small teeth/ large jaws - missing teeth - midline supernumerary - prominent frenum - proclined upper incisors

Question 52

management of median diastema?

Answer 52

radiograph to exclude pathology try and eliminate cause if possible likely to reduce as permanent teeth erupt less than 3mm rarely require rx large diastema - fixed appliance and permanent retention

Question 53

management of impacted Es?

Answer 53

not common often improve with no intervention place separator

Question 54

cause of impacted central incisors?

Answer 54

supernumerary crown root dilaceration trauma premature loss of deciduous

Question 55

management of impacted central incisor?

Answer 55

remove obstruction expose URA to align

Question 56

management of impacted canines?

Answer 56

palpate 8-10 years radiographs if ectopic good chance will erupt if intervene (xla Cs) failure to improve - treat in permanent dentition (expose/xla/leave)