Dental Anomalies Flashcards
How to approach developmental anomalies?
- Quantity: too many teeth? Too little teeth?
- Size: too big? Too small?
- Shape: is the morphology unusual?
- Aetiology: genetic or environmental?
Q.S.S.A:
“Queering seen situations accurately”
Hypodontia: Anodontia
Total lack of teeth in one or both dentitions
Hypodontia: Oligodontia
Rare condition where more than 6 primary or permanent teeth are absent.
Hypodontia: Prevalence
Primary dentition <1%
Permanent dentition 3-6%
More common in females 4:1
Hypodontia: third molars?
Missing 3rd molars in up to 30% of people.
Hypodontia: most commonly missing teeth
- Wisdom teeth
- lower 1st premolars
- Upper lateral incisors
- Upper 1st premolars
Hypodontia: ___% of patients with missing primary teeth also have missing permanent teeth.
50
Hypodontia: aetiology
Considered likely to be genetic (however could be in combination with environmental insult).
Hypodontia: associated syndromes
Down syndrome (trisomy 21)
Ectodermal dysplasia
Hypodontia: genetic issues
Autosomal dominant inheritance pattern in some families
Mutation in the MSX1 gene on chromosome 4
Ectodermal dysplasia
Occur when the outer layer of tissue (ectoderm) of the embryo does not develop normally.
Oral manifestiations: conical or pegged teeth, hypodontia or complete anodontia and delayed eruption of permanent teeth.
Other major symptoms: fewer sweat glands, putting infants at risks at overheating.
Age of this patient? Caries risk of this patient?
8-9 years old
6s present; over 6 years old.
7s furcations developing.
Lower 3s coming in = 9 years.
High caries risk; look at lower left 6 distal cusp (would consider extracting this tooth if 5 was present) and upper left 6 distal cusp. Overcrowding on upper left hand side liaise with orthodontist consultant.
What’s missing here?
Complex Hypodontia case, teeth missing:
Two upper lateral incisors.
One lower central incisor.
Lower right 5.
Upper left 5.
Where is caries present?
Lower right 6
Upper left 6
Lower left 6
Supernumerary teeth: prevalence
Primary dentition: 0.2-0.8%
Permanent dentition: 1.5-3.5%
Anterior maxilla most common site
Supernumerary teeth: associated conditions
Cleft lip and palate (40% of cases)
Cleidocranial dysostosis
Supernumerary teeth: mesiodens
In the midline; usually peg shaped teeth
Supernumerary teeth: supplemental teeth
Look like a normal tooth
Supernumerary teeth: Conical supernumeraries
If not inverted, there is a good chance they will erupt.
If not impeding eruption of other teeth, can be monitored until erupted and then extracted.
If inverted, they may migrate superiority towards nose.
Supernumerary teeth: Tuberculate supernumaries
Don’t tend to migrate but may impede eruption of adjacent teeth
Cleidocranial dysostosis
- The collar bones may be missing or abnormally developed.
- Delayed exfoliation, delayed or failing eruption of the permanent dentition with multiple supernumerary teeth, protruding mandible, and mid-face retrusion.
What are key considerations with unusual eruption patterns?
- Correct sequence of eruption
- Symmetry (if one tooth has come in and the other hasn’t, after 6 months - there would be concern).
What kind of supernumary teeth are these?
Conical (mesiodens - in the midline)
Where is this supernumerary tooth located (palatal or labial)?
Palatal (because as the X-ray tube has moved to take the other view of the tooth, the tooth appears to be going up the way)
Locate this supernumerary tooth.
Palatal (“x-ray tube has moved with the tooth”)
Where is the supernumerary tooth on this radiograph and what kind of tooth is it (how might this impact clinically)?
Inverted supernumerary tooth (upside down: wants to move in the direction of the arrow).
Clinical implications means this tooth will not erupt.
Microdontia: peg shaped teeth
Peg shaped laterals
Microdontia: Prevalence
Primary teeth: 0.2-0.5%
Permanent teeth: 2.5%
More common in females than males
Lateral incisors most affected