OS - impacted incisors and premolars Flashcards
when would you class a maxillary incisor’s eruption being delayed?
- contralateral teeth erupted 6 months previously
- both upper centrals are missing the year after eruption of lower incisors
- deviation from normal eruption sequence
what are the hereditary aetiology’s of delayed incisor eruption?
supernumeraries (most common)
cleft lip/palate
cleidocranial dysostosis
odontomes
abnormal tooth/ tissue ratio
gingival fibromatosis
generalised retarded eruption
what are the environmental aetiologies of delayed incisor eruption?
trauma = root dilaceration (most common)
early loss or extracted deciduous tooth
retained deciduous tooth
cyst formation
endocrine abnormalities
bone disease
when examining delayed incisor eruption, what should you look for?
retained deciduous teeth (if not mobile, root resorption)
palpable buccal/ palatal mass
lack of space
erupted mesiodens/ supernumeraries
what type of radiographs are commonly used to assess supernumeraries/ delayed eruption?
parallax with 2 PAs
what is the most common management technique of impacted incisors?
interceptive exposure
removal
when you create and maintain space, how many incisors will erupt spontaneously and align spontaneously?
75% erupt spontaneously
55% align spontaneously
what is the treatment for severely dilacerated incisors?
surgical removal
what are the 2 techniques for exposure of incisors?
open technique - labial flap raised, taking away as much attached gingivae as possible, repositioned apically and packed
closed technique - using brackets and gold chains
how does flap raising differ between canines and incisors?
buccal flap raised for incisors
palatal for canines
supernumeraries often impede eruption of incisors, what else can they affect?
alignment - rotation
explain the open technique for incisor exposure
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
why is the open technique not commonly advocated for impacted incisors?
can lead to poor gingival aesthetics
can lead to exposed roots = sensivity, caries
explain the closed technique for incisor exposure
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
what is the aetiology of impacted mandibular premolars?
crowding
pathology
ankylosed deciduous tooth
supernumeraries
genetic disorders
what does removal of impacted mandibular premolars involve?
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
a supplemental premolar is seen radiographically erupting between the first and second mandibular premolar. what are the risks of this?
high caries if erupts
cystic transformation around crown of impacted tooth - can cause external root resorption on other premolars
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?
no indication to extract
conservative treatment plan
bridge for the space
a patients second maxillary premolars have erupted palatally, with no space in the arch. What is the treatment plan?
caries risk so removal
cannot use forceps, so elevate or surgical removal
what type of flap is used for surgical exposure of a mandibular premolar?
2 sided MP flap
1. pericoronal incision
2. mesio relieving incision into sulcus (beware of mental foramen
closed or open depending on position
what are common positions of supernumerary teeth?
palatal maxilla
premolar/ third molar (supplemental teeth)
what are common types of supernumerary teeth? what types of supernumeraries tend to erupt/ not erupt?
conical or tuberculate
often conical supernumeraries between centrals erupt = mesiodens
tuberculate tend not to erupt but prevent eruption of adjacent teeth
how are mesiodens removed?
easily removed as small root - elevation, minimal LA
what do supplemental supernumeraries look like?
permanent teeth
in what genetic condition may you find multiple unerupted impacted teeth?
cleidocranial dysostosis
what are the 2 types of odontomes?
complex - bag of small teeth
compound - aggregation of enamel, dentine, cementum and pulp (no tooth structures seen)
how are complex odontomes formed?
invaginations of tooth germ
what are odontomes?
hamartomas (mostly a benign mass of disorganized tissue native to a particular anatomical location)
sometimes referred to as odontogenic tumours
how are compound odontomes formed?
exuberant proliferation of dental lamina - consists of a number of denticles
when would you surgically remove an odontome?
impeding eruption
associated pathology
