OS - impacted incisors and premolars

Question 1

when would you class a maxillary incisor’s eruption being delayed?

Answer 1

• contralateral teeth erupted 6 months previously
• both upper centrals are missing the year after eruption of lower incisors
• deviation from normal eruption sequence

Question 2

what are the hereditary aetiology’s of delayed incisor eruption?

Answer 2

supernumeraries (most common)
cleft lip/palate
cleidocranial dysostosis
odontomes
abnormal tooth/ tissue ratio
gingival fibromatosis
generalised retarded eruption

Question 3

what are the environmental aetiologies of delayed incisor eruption?

Answer 3

trauma = root dilaceration (most common)
early loss or extracted deciduous tooth
retained deciduous tooth
cyst formation
endocrine abnormalities
bone disease

Question 4

when examining delayed incisor eruption, what should you look for?

Answer 4

retained deciduous teeth (if not mobile, root resorption)
palpable buccal/ palatal mass
lack of space
erupted mesiodens/ supernumeraries

Question 5

what type of radiographs are commonly used to assess supernumeraries/ delayed eruption?

Answer 5

parallax with 2 PAs

Question 6

what is the most common management technique of impacted incisors?

Answer 6

interceptive exposure
removal

Question 7

when you create and maintain space, how many incisors will erupt spontaneously and align spontaneously?

Answer 7

75% erupt spontaneously
55% align spontaneously

Question 8

what is the treatment for severely dilacerated incisors?

Answer 8

surgical removal

Question 9

what are the 2 techniques for exposure of incisors?

Answer 9

open technique - labial flap raised, taking away as much attached gingivae as possible, repositioned apically and packed
closed technique - using brackets and gold chains

Question 10

how does flap raising differ between canines and incisors?

Answer 10

buccal flap raised for incisors
palatal for canines

Question 11

supernumeraries often impede eruption of incisors, what else can they affect?

Answer 11

alignment - rotation

Question 12

explain the open technique for incisor exposure

Answer 12

3 sided MP flap allows crowns to be exposed
1. mesial and distal relieving incision
2. crestal/ pericoronal incision

flaps relocated so they sit apically to original position

Question 13

why is the open technique not commonly advocated for impacted incisors?

Answer 13

can lead to poor gingival aesthetics
can lead to exposed roots = sensivity, caries

Question 14

explain the closed technique for incisor exposure

Answer 14

3 sided flap
removal of overlying tissue to expose labial surface of incisor
ortho bracket with gold chains are cemented to exposed crowns
MP flap suture back with gold chains exposed to allow attachment of ortho appliance

Question 15

what is the aetiology of impacted mandibular premolars?

Answer 15

crowding
pathology
ankylosed deciduous tooth
supernumeraries
genetic disorders

Question 16

what does removal of impacted mandibular premolars involve?

Answer 16

buccal flap, avoiding damage to mental bundle, elevate/ section tooth to remove as atraumatically as possible

removal of adjacent premolar may be preferred by ortho

Question 17

a supplemental premolar is seen radiographically erupting between the first and second mandibular premolar. what are the risks of this?

Answer 17

high caries if erupts
cystic transformation around crown of impacted tooth - can cause external root resorption on other premolars

Question 18

radiographically, you can se an ectopic/ intraosseous premolar. It has no plan of eruption, it creates a space between tooth 43 and 46. What is the treatment plan?

Answer 18

no indication to extract
conservative treatment plan
bridge for the space

Question 19

a patients second maxillary premolars have erupted palatally, with no space in the arch. What is the treatment plan?

Answer 19

caries risk so removal
cannot use forceps, so elevate or surgical removal

Question 20

what type of flap is used for surgical exposure of a mandibular premolar?

Answer 20

2 sided MP flap
1. pericoronal incision
2. mesio relieving incision into sulcus (beware of mental foramen

closed or open depending on position

Question 21

what are common positions of supernumerary teeth?

Answer 21

palatal maxilla
premolar/ third molar (supplemental teeth)

Question 22

what are common types of supernumerary teeth? what types of supernumeraries tend to erupt/ not erupt?

Answer 22

conical or tuberculate
often conical supernumeraries between centrals erupt = mesiodens
tuberculate tend not to erupt but prevent eruption of adjacent teeth

Question 23

how are mesiodens removed?

Answer 23

easily removed as small root - elevation, minimal LA

Question 24

what do supplemental supernumeraries look like?

Answer 24

permanent teeth

Question 25

in what genetic condition may you find multiple unerupted impacted teeth?

Answer 25

cleidocranial dysostosis

Question 26

what are the 2 types of odontomes?

Answer 26

complex - bag of small teeth
compound - aggregation of enamel, dentine, cementum and pulp (no tooth structures seen)

Question 27

how are complex odontomes formed?

Answer 27

invaginations of tooth germ

Question 28

what are odontomes?

Answer 28

hamartomas (mostly a benign mass of disorganized tissue native to a particular anatomical location)
sometimes referred to as odontogenic tumours

Question 29

how are compound odontomes formed?

Answer 29

exuberant proliferation of dental lamina - consists of a number of denticles

Question 30

when would you surgically remove an odontome?

Answer 30

impeding eruption
associated pathology