1. Aetiology and extractions Flashcards

1
Q

Describe the main aetiological factors in malocclusions

A
  • GENERAL FACTORS
  • SKELETAL RELATIONSHIP
  • TOOTH SIZE / ARCH SIZE DISPROPORTION
  • soft tissues
  • genetic and developmental disorders
  • TMJ trauma / growth abnormalities
  • LOCAL FACTORS (more important to us as they are the ones we can identify and prevent/ treat in children/adolescents)
  • EARLY LOSS / PROLONGED RETENTION OF DECIDUOUS TEETH
  • ECTOPIC TEETH
  • Absent teeth, supernumeraries
  • Impaction, delayed eruption
  • Fraenum, local pathology
  • Dental trauma
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2
Q

Describe the main local factors and anomalies that may present in the developing dentition

A
  • Deciduous Teeth
    – Early loss or prolonged retention of deciduous teeth
  • Permanent: number of teeth
    –Absent teeth
    –supernumeraries
    –early loss (6s, 1s)
  • Permanent: position of teeth
    –ectopic canines
    –impaction of 1st molars, or premolars
  • Fraenum
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3
Q

what are the effects of early loss of upper E

A

impacted and crowded lower premolar

(E extracted due to caries)
6 drifting mesially and not leaving enough space for the 4 and 5 ie posterior crowding

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4
Q

Fitted in patient who has lost both lower Es-
(to prevent the 6 drifting forwards

A

Space maintainers ie lingual arch (fixed)

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5
Q

Early Loss of Deciduous Teeth
Effects depend on:

A
  • Tooth lost
  • Age
  • Degree of Crowding in the Arch
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6
Q

Effects of early loss of deciduous teeth- tooth loss

A

–D, E space loss as 1st permanent molars drift mesially
(causes premolar crowding)
–C incisor midline shift as permanent incisors drift into
space
–A, B minimal effect

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7
Q

Effects of early loss of deciduous teeth- age

A

–Effects more severe with earlier loss

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8
Q

Effects of early loss of deciduous teeth- degree of crowding in the arch

A

–more space loss with D or E loss if crowding present
– greater midline shift with C loss if perm incisors crowded

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9
Q

Prolonged Retention of Deciduous
Teeth
(how common, which teeth and effects? what happens?)

A
  • Relatively common
  • Usually Es or Ds (radiograph re. successor)
  • May delay permanent successor
  • May become “submerged” or “infraoccluded” due to ankylosis
    –tipping of adjacent teeth (first molars)
    –almost all exfoliate naturally
    –extract only if becoming completely submerged
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10
Q

Developmental Absence of
Permanent Teeth (“Hypodontia”)
how common and what other type of lack of teeth canyou have?

A

Relatively common (2-3%)
* Anodontia (complete absence)

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11
Q

what are the most common teeth missing? and what is severe hypodontia?

A

excluding 3rd molars:
upper laterals, then 2nd premolars, and lower central incisors

6 or more missing teeth (excluding 8s)

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12
Q

Tx of hypodontia?

A
  • space closure
  • Open or maintain space then bridgework / implants / denture
  • accept (e.g. lower 5s)
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13
Q

Hypodontia: Upper Laterals
. how common
. associated with?
. Tx?

A
  • Common (2-3%)
  • Associated with ectopic canines and small
    contralateral lateral incisors
    *–space closure (crowding, Class II cases, 3s acceptable)
    –bridgework (no crowding, 3s poor colour)
    –usually need fixed appliances
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14
Q

Absent Second Premolars
- how common?
- can appear on Rx as late as?
- Tx?
- Prognosis?

A
  • Common (2%)
  • Can appear on radiographs as late as age 8 years
  • – space closure (extract deciduous early)
    – bridgework
    – use space to treat crowding
    – accept and retain Es
    0 uncertain, unusual to last beyond age 30
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15
Q

Absent Lower Central Incisors- features?
treatment?

A
  • Rare
  • A`s usually retained
  • Close space or bridgework
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16
Q

Supernumerary Teeth ($)
incidence? and location?

A
  • Incidence 1-2%
  • 80% are in the anterior maxilla
    (* OPG
  • anterior occlusal)
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17
Q

Supernumary teeth classification?

A
  • Morphology (Coniform and Tuberculate)
  • Position (Mesiodens, Supplemental, Paramolar)
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18
Q

Supernumary teeth clinical effects?

A
  • delayed eruption of teeth (e.g. Upper centrals)
  • may erupt (mesiodens), crowding
  • midline diastema (mesiodens)
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19
Q

Supernumerary Teeth: Treatment

A
  • No treatment
  • Extract
  • Exposure and alignment of teeth with delayed eruption (Upper incisors)
  • However, more than 70% of unerupted upper central incisors will erupt following removal of a supernumerary tooth
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20
Q

Impacted teeth

A
  • First permanent molars
  • Premolars
  • Third molars
21
Q

Impacted Teeth: Perm First Molars
incidence
location
prognosis?

A

3-4 percent
almost always in maxilla
2/3 will correct spontaneously, although unlikely to improve after 8 years

22
Q

treatment of impacted permenant first molars?

A
  • extraction of E
  • Simple URA to disimpact
23
Q

Impacted Teeth: Premolars
- what tooth and why

A

Usually 2nd premolars
Early loss of E

24
Q

Tx of impacted premolars

A
  • Extract 4 to allow eruption of 5
  • Extract 7 and distalise 6 to create space
  • Extract 5 (surgical)
  • No treatment and review regularly
25
Ectopic Maxillary Canines incidence?
2 percent see separate lecture
26
Local Factors: Labial Fraenum- what is it and sometimes associated with?
Abnormally thick upper labial fraenum * midline diastema
27
Treatment of labial fraenum?
* wait until upper canines erupted before treating * fraenectomy during or after space closure
28
Early loss of Permanent Teeth- with which?
* 1st molars (caries) * Upper incisors (trauma)
29
Early loss of Permanent 1st Molars * Why is it a problem?
* Residual space * overeruption of opposing first molar * space is difficult to use with appliances for treating anterior crowding or overjet
30
ideal age for spontaneous closure of 6s?
8-9
31
features of early loss of 6s?
upper spaces close better than lower unopposed 6s overerupt
32
what is minimal with early loss of 6s?
midline shift with unilateral loss of a 6
33
management of carious 1st molars is done how?
extraction best at age 8-9
34
risk of later extraction?
tipping
35
consideration for extraction of carious 6s
extraction of both upper and lower
36
lower 3rd molars?
very weak associated with lower incisor crowding later lower incisor crowding alone is not an indication for lower 3rd molar extraction
37
urgical removal of impacted third molars should be limited to patients with
evidence of pathology
38
Early Loss of Permanent Upper Incisors is due to ... and is seen in
trauma class II Div 1
39
early loss of permenant upper incisors is associated with
poor lower lip coverage
40
treatment of early loss of permenant upper incisors?
try to save if at all possible, (RCT, re-implant)
41
what are the options if lost or unsavable permanant upper incisors?
* Maintain space with prosthesis * Close space orthodontically and crown lateral poor gingival margin & canine colour
42
abnormal tooth form?
* Dilaceration of permanent upper incisors * Peg shaped upper lateral incisors * strong association with ectopic canines * other lateral may be absent
43
what is dilaceration of upper lateral incisor, due to what
* root bent * trauma to deciduous predecessor, age 4-5
44
prognosis of dilacerated upper lateral
* delayed or non-eruption * orthodontic alignment sometimes possible
45
peg shaped upper laterals have a strong association with ... and the ... may be absent
ectopic canines other lateral
46
most malocclusions are the result of complex and poorly understood interaction of
genetic and environmental factors
47
... and ... are superimposd on the genetic background
habits and local factors
48
simple measures can solve and treat successfully
local factors and habits
49
more complex treatment may be needed for
skeletal problems and tooth-arch size disproportions (crowding and spacing)