Dental Anomalies Flashcards
Hypodontia?
The developmental absence of primary or permanent teeth.
Oligodontia?
Developmental absence of 6 or more teeth (excluding 8s).
Anodontia?
Complete absence of teeth (developmental, not acquired).
Aetiology of hypodontia - at what stage does this occur?
- Occurs at INITIATION stage of dental development.
Another term for ankylosed tooth?
Infraocclusion
Role of dentist in hypodontia treatment?
- Early detection.
- Prevention
- Early referral
When does tooth formation begin?
6 weeks IUL
5 stages to tooth formation?
- Dental lamina.
- Bud stage
- Cap stage.
- Bell stage.
- Eruption.
Name the processes that occur during tooth formation? (4)
- Initiation
- Morphogenesis.
- Cell differentiation.
- Matrix secretion.
What is the process of enamel deposition called? What is it controlled by? What are the 3 stages?
- Amelogenesis
- Ameloblasts
- Secretory, calcification & maturation phase.
What is the process of dentine deposition called? What is it controlled by?
- Dentinogenesis
- Odontoblasts
What is hypodontia strongly associated with?
Strong GENETIC component:
- Single gene defects (ex. MSX1).
- Feature of many syndromes.
ENVIRONMENTAL component:
- Severe disease and cancer treatment in early childhood.
4 syndromes strongly associated with hypodontia?
- Trisomy 21.
- Ectodermal dysplasia.
- Cleft lip and palate.
- Solitary median maxillary central incisor syndrome.
Is hypodontia more prevalent in permanent vs primary dentition? M or F?
- More prevalent in PERMANENT.
- More prevalent in FEMALES.
Which teeth are most often affected by hypodontia?
- 3rd Molars (not considered hypodontia).
- Mandibular second premolars.
- Maxillary lateral incisors.
- Maxillary second premolars.
- Mandibular central incisors.
What is the significance of an absent primary tooth?
HIGH PROBABILITY THAT THE SUCCESSOR WILL BE ABSENT.
9 clinical features that would raise suspicion of hypodontia?
- Failure of a primary tooth to exfoliate at the expected time.
- Permanent tooth hasn’t erupted several months after the primary exfoliates.
- Teeth erupting out of sequence.
- The contralateral tooth has been erupted for some time (>6months should raise suspicion).
- Other teeth appear unusually spaced.
- Primary tooth may become infraoccluded.
- Microdontia - high suspicion if there is microdontia of any erupted teeth.
- Ectopic position of other permanent teeth (ex. palatally ectopic maxillary canines where lateral incisors are missing).
- No tooth palpable in the buccal or lingual/palatal sulcus.
How is diagnosis of hypodontia confirmed?
RADIOGRAPH
1. Periapical (does not rule out ectopic teeth so if not present in expected position:)
2. DPT (confirm hypodontia and assess for other missing teeth).
What is very important for patients with hypodontia?
PREVENTION (fewer teeth so must remain caries free)
Can primary teeth be kept in cases of hypodontia?
YES, if they have:
- good root length.
- no significant infraocclusion.
What is ectodermal dysplasia?
Group of diseases affecting the structures arising from the ectoderm:
- Teeth, hair, nails, sweat glands, salivary glands.
What is the most known type of ectodermal dysplasia?
X linked hypohydrotic ectodermal dysplasia.
What is the clinical appearance of x linked hypohydrotic ectodermal dysplasia?
- Sparce hair.
- Dry skin.
- Inability to sweat.
- XEROSTOMIA, CONICAL TEETH, MICRODONTIA AND HYPODONTIA.
- Dry eyes.
- Nasal Congestion
Supernumerary?
Presence of a tooth/teeth in addition to the normal sequence.
When do supernumeraries occur during tooth development
At the INITIATION stage of tooth formation.
What causes supernumerary teeth?
- GENETIC, often runs in families.
- A feature of some syndromes.
3 syndromes associated with supernumerary teeth?
- Cleidocranial dysplasia.
- Cleft lip and palate.
- Gardner syndrome.
Are supernumeraries more common in primary or permanent? M or F?
- More often in PERMANENT.
- More often in MEN
What is the significance of a primary tooth supernumerary?
- 35-50% chance there will be a supernumerary in the PERMANENT.
2 ways in which supernumeraries can be defined?
POSITION (mesiodens, paramolar) or SHAPE.
4 different SHAPES of supernumeraries?
- Conical.
- Tuberculate.
- Supplemental.
- Odontome.
What is the most common supernumerary shape?
Conical
6 facts about conical supernumeraries?
- Most COMMON.
- Likely to erupt if not inverted but not always.
- Often impede eruption of other teeth.
- Often occur in MIDLINE maxilla.
- Often in pairs.
- Often inverted.
Which part of the maxilla/ mandible do conical supernumeraries often occur?
Often MIDLINE MAXILLA.
What are the radiographic features suggestive of hypodontia?
- PERIAPICAL.
- DPT (as PA does not rule out ectopic teeth so if not present in expected position DPT confirms hypodontia + allows to assess for other missing teeth).
How is a hypodontia diagnosis confirmed?
RADIOGRAPH.
Who is invilcved in the treatment of hypodontia?
Multidisciplanary approach.
- GDP (makes diagnosis).
- Orthodontist.
- Pediatric dentist.
- Restorative dentist.
3 requirements to maintain primary teeth for years if permanent are absent?
- Healthy.
- Good root length.
- No significant infraocclusion.
Which primary teeth are good for being maintained when their permanent successors are absent?
Second primary molars
What sex are hypodontia and supernumeraries more common in?
- Hypodontia: F
- Supernumerary: M
How can supernumeraries be defined in terms of position?
- Mesiodens.
- Paramolar.
Name the 4 supernumeraries (shape) in terms of most to least common?
Conical, Tuberculate, Supplemental, Odontome
Which supernumeraries are likely to erupt? Which not?
- Conical: likely to erupt if not inverted (not always + often inverted).
- Supplemental: Likely to erupt (especially supplemental incisors).
- Tuberculate: Do not usually erupt.
- Odontome: Will not erupt.
What is the shape of tuberculate supernumeraries?
Barrel shaped.
Which supernumeraries often occur in pairs?
Conical, tuberculate.
Which supernumeraries are likely to impede the eruption of nearby teeth?
- Conical: often but not always.
- Tuberculate: VERY likely.
- Supplemental: Less likely.
- Odontome: VERY likely.
What teeth are usually supplemental?
- Supplemental lateral incisor.
- 3rd premolar.
- 4th molar.
What is an odontome? The 2 types?
- Collection of tooth tissue.
- Compound: denticles.
- Complex: disorganized collection of tooth tissue.
What are the 2 first signs of a supernumerary tooth?
- Eruption of the supernumerary.
- Delayed eruption of the normal sequence.
Where do supernumerary teeth often occur? What does this lead to?
- ANTERIOR MAXILLA.
- Delayed eruption of central incisor.
4 things that supernumerary teeth can cause to surrounding primary teeth?
- Crowding.
- Rotation.
- Malposition.
- Ectopic position.
How do you radiographically locate an unerupted supernumerary?
- PARALLAX.
- CBCT (when necessary).
A supernumerary tooth has erupted and been diagnosed clinically, do we still need a radiograph?
POTENTIALLY to:
- Exclude the presence of unerupted supernumeraries
- Especially when permanent dentition not fully established/ orthodontic treatment is planned.
When would you take a radiograph if suspecting a supernumerary?
- Permanent tooth is still not erupted MORE THAN 6 MONTHS after the contralateral tooth.
- And/or teeth are erupting out of sequence.
4 management methods for supernumeraries?
- Monitor.
- Simple XLA.
- Surgical XLA.
- Surgically expose + orthodontically repositioned.
What is cleidocranial dysplasia?
Rare autosomal dominant condition.
Non dental features of cleidocranial dysplasia (3)?
- Hypoplastic/ absent clavicles.
- Short.
- Characteristic facial features.
Dental features of cleidocranial dysplasia?
- Multiple supernumerary teeth.
- Delayed/ failed exfoliation of primary teeth.
- Delayed/ failed eruption of permanent teeth.
