ortho perspective on developmental anomalies Flashcards

1
Q

are supernumeraries more common is men or women?

A

Men, twice as much as women

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2
Q

how are the conical-shaped teeth characterised and are they late forming or early forming?

A

peg shaped, early forming

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3
Q

how are the Tuberculate-shaped teeth characterised and are they late forming or early forming?

A

barrel shaped, late forming

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4
Q

name the different groups when classifying teeth by form/shape

A

1- Supplemental (extra tooth of normal (ish) form
3 - Conical – generally early forming and peg-shaped
3 - Tuberculate – generally late forming and barrel-shaped
4 - Odontome

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5
Q

what are the two different presentations of odontomas

A
  • Compound – Containing many small separate tooth-like structures (denticles) –usually found anteriorly
  • Complex – a large mass of disorganised enamel and dentine – usually found posteriorly
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6
Q

name the different groups when classifying teeth by site/ position

A
  • Mesiodens – midline between the central incisors
  • Paramolar / para premolar – adjacent to the molars/premolars
  • Distodens/Distomolar – distal to the arch
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7
Q

where are the conical teeth usually found and what are the consequences on teeth appearance if they erupt

A
  • they are usually found in the midline (mesiodens)
  • if they erupt, they cause diastema
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8
Q

what is the risk of cystic formation and eruption impeding in the conical teeth

A
  • low risk of impeding eruption and may erupt
  • low risk of cystic formation or resorption
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9
Q
  • Do Tuberculate teeth impede eruption?
  • where does it usually found?
  • is it fine to be left or does it need to be removed?
A
  • yes they are more likely to impede eruption
  • often found palatally
  • need to be removed
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10
Q

what are the conditions associated with supernumerary?

A
  • Gardner syndrome
  • Cleidocranial dysostosis
  • Cleft lip and palate
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11
Q

What does Gardner syndrome cause? and what condition of teeth is it associated with?

A
  • associated with supernumerary
  • a very rare inherited syndrome, which causes multiple precancerous polyps in the colon as well as tumours elsewhere, which can include osteomas in the skull.
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12
Q
  • What does Cleidocranial dysostosis cause?
  • What condition of teeth is it associated with?
A
  • associated with supernumerary
  • This condition which either inherited or a new mutation on the RUNX2 gene.
  • Cleido – refers to the collarbones, and cranial refers to the skull.
  • It causes the collarbones to be partly or completely missing, a hypoplastic maxilla making them usually look class III, and they will also often have multiple supernumerary teeth.
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13
Q

What are the problems with supernumerary teeth?

A
  • Impede eruption of other teeth
  • Cause displacement or rotation of erupted teeth
  • Produce spacing between erupted teeth
  • Contribute to crowding if they erupt
  • Undergo cystic change
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14
Q

what genes associated with Hypodontia

A

MSX1
PAX9
AXIN2

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15
Q

what are the three different classifications of hypodontia and what do they mean

A
  • Hypodontia – the absence of <6
  • Oligodontia –the absence of ≥6 teeth
  • Anodontia – the absence of all teeth
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16
Q

what are the conditions associated with Hypodontia?

A
  • Cleft lip and palate
  • Downs syndrome
  • Ectodermal dysplasia
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17
Q

what is Ectodermal dysplasia? what does it cause and which condition of teeth is it associated with?

A
  • a group of genetic disorders which involve defects of the hair, skin, nails, teeth, mucous
    membranes and sweat glands.
  • Derived from the ectoderm
    primary germ layer
  • Associated with Hypodontia
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18
Q

what is the treatment options for Hypodontia?

A
  1. Open up the space and add teeth as prosthetics
  2. Do ortho and close the gap to camouflage the missing teeth
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19
Q

what’s the definition of microdontia

A

Teeth which have smaller than average dimensions (more than 2 standard deviations) – range from mildly to severely

20
Q
  • Which tooth is mostly affected by microdontia?
  • what treatment option is available for it?
A
  • upper lateral (peg-shaped)

Treatment
- Accept – generally done if mild or in a less aesthetically challenging area e.g. upper 7s
- Create space to have the microdont teeth built up
- Extract the microdont tooth and close the space

21
Q

Which teeth most commonly affected by macrodontia?

A

Upper 1s / lower 5s are most commonly affected – often bilateral

22
Q

What is the treatment option for Macrodontia?

A
  • Accept – generally done if mild or in a less aesthetically challenging area e.g. lower 5s
  • Extract and reduce space for a normal-sized prosthesis
  • Extract and close the space
  • Camouflage restoratively to resemble 2 teeth e.g. if a very large upper 1 and missing upper 2 (crown will be put on top of 1 which has an attached 2)
23
Q

What is the definition of Fusion?

A

fusion of 2 separate tooth germs leading to a reduced number of teeth in the arch (it looks like one tooth with a slight split in the middle)

24
Q

What is the definition of Germination?

A

Developmental separation of a single tooth germ (one root but crown looks separated)

25
Q

Are the double teeth more common in primary or secondary dentition? and what is their prevalence from female to male?

A
  • More common in primary (0.5-1.6%) than secondary (0.1-0.2%) dentition and anteriorly
  • Female: Male = 1:1
26
Q

Treatment for double teeth (fusion/germination)?

A
  • No intervention is needed in the primary dentition
  • Be wary of caries at the interface between the 2 crown segments, especially if extending
    subgingival – may want to restore any notch for aesthetic and preventative reasons
  • If 2 separate root canals – can surgically divide
  • Extract
27
Q

What is tooth Invagination?

A

An enamel lined ‘infolding’ in the crown of a tooth, which can extend into the root
- Upper 2s most commonly affected, followed by upper 1s

28
Q

What is the management of Invagination

A
  • Although defects are generally enamel lined, this can be of poor quality and very thin
  • Difficulty cleaning means high caries risk and bacterial ingress to the pulp leading to pulpal disease
  • Can try to maintain less severe forms with adhesive restorations
  • Can attempt RCT but often challenging due to abnormal morphology
  • If grossly abnormal, extraction may be the best option with space closure of prosthetic replacement
29
Q

What is Dilaceration?

A

An abrupt deviation along the long axis of the crown or root
- Upper incisors most commonly affected
- Can lead to failure of eruption

30
Q

What is the managment of Dilaceration?

A

Management
- If less marked divergence, can expose, bond traction and attempt orthodontic
alignment – need to consider where the root will end up once the crown is aligned
- If more significant, will likely need to remove – extraction can be challenging

31
Q

What is the aetiology of Dilaceration?

A

Traumatic – due to intrusion of a primary incisor into developing tooth germ
- Position of dilaceration corresponds with the stage of development at the time of trauma
- Generally, crown is angled palatally and hypoplasia was seen at the site of dilaceration

Developmental – may be due to an obstruction of the eruption path
- Generally, crown is angled upward and labially and no hypoplasia is seen
- Upper 1s most commonly affected

32
Q

what is the time range that by then the bilateral tooth should have erupted?

A

6-12 months.
If the tooth still has not erupted, Investigate!

33
Q

Name some systemic conditions associated with delayed eruption

A
  • Cleidocranial Dysostosis
  • Down Syndrome
  • Cleft Lip and Palate
  • Hereditary Gingival Hyperplasia
34
Q

Name some Local factors associated with delayed eruption

A

Crowding / Supernumeraries
Trauma / Dilaceration
Ectopic Tooth Germ
Early Loss of Primary Teeth
Retention of Primary Teeth
Local Pathology
Transpositions

35
Q

What is the difference between Ectopic and Impacted teeth?

A
  • Ectopic – abnormal place or position
  • Impacted – physical impediment to eruption by another structure such as bone, adjacent teeth, soft tissues
36
Q

Aetiology of unerupted teeth

A
  • Polygenic multifactorial
  • Genetic theory
    o Family history
    o frequency bilateral than expected
    o Associated malformations
  • Guidance theory / local factors
    o Missing or absent lateral incisor
    o Retention of Primary canine
    o Crowding
37
Q

What is the consequence of unerupted teeth?

A

Root resorption
- Up to 2/3 U2s have RR when U3s ectopic
- Most RR occurs before 14
- How much is clinically significant?

Coronal resorption
- Most likely in adults
- Cystic change
- Generally thought to be low risk, especially in older patients

38
Q

When should we start palpating for canines?

A
  • caNINE= 9 years old
  • majority of maxillary canine should be palatable by the age of 10
39
Q

When is the canine eruption considered to be late?

A

Considered late if not erupted before 12.3 years in girls and 13.1 years in boys

40
Q

How long should it be between the eruption of two bilateral canines?

A

they should erupt within 6 months

41
Q

When should we consider referrals for unerupted canines?

A

If not palpatable by the age of 10!

42
Q

What is Mechanical Failure of Eruption / Ankylosis

A
  • The uncommon, isolated condition causing a localised failure of eruption of a single tooth with
    no other identifiable causes
  • May partially erupt and then appear to submerge due to continued vertical growth of the
    rest of the alveolar complex
43
Q

Management of Ankylosis?

A

The teeth fail to respond to orthodontic forces – often removal is indicated

44
Q

What’s the difference between prevalence of Cleft palate compared with cleft lip and palate?

A
  • Cleft lip and palate: more common, 2:1 Male: Female, more common in Asians than Africans
  • Cleft Palate: less common and less racial variation, 4:1 Male: Female
45
Q

What are the key dental findings in Down Syndrome?

A
  • Class III malocclusion - maxillary hypoplasia
  • Hypodontia
  • CLP
  • Microdontia
  • Delayed eruption of 2ry dentition
  • Short roots
46
Q

What are the key dental findings in Ectodermal Dysplasia?

A
  • Class III malocclusion
  • Anodontia / severe hypodontia
  • Deformed teeth / conical crowns
  • Delayed eruption
  • Xerostomia
  • CLP
47
Q

What are the key dental findings in Cleidocranial Dysostosis?

A
  • Class III malocclusion - Mx hypoplasia
  • Multiple supernumerary teeth
  • Dentigerous cysts
  • Retained 1ry teeth
  • Failure of eruption of 2ry teeth