DP01 developmental anomalies of teeth Flashcards
(46 cards)
Teeth form from the ectoderm and ectomesenchyme (from neural crest). What does the ectoderm give rise to?
Enamel
Teeth form from the ectoderm and ectomesenchyme (from neural crest). What does the ectomsenchyme give rise to?
Dentine, pulp, cementum, PDL, bone
What is the inductive theory?
IEE (preameloblasts) induce the dental papillae to differentiate preodontoblasts. Odontoblasts produce dentine. Dentine stimulates preameloblast maturation into ameloblasts which form enamel.
What might anomalies affect in teeth?
Size, number, form, structure, sequence of eruption, position
What are the anomalies of size?
Macrodontia
Microdontia
What is macrodontia of the roots caused by?
Rare disease - oculo-facio-cardio-dental syndrome
X-linked - lethal in males
Involves BCOR gene
What effects does oculo-facio-cardio-dental syndrome have?
→ Ocular: congenital cataracts, microphthalmia, secondary glaucoma
→ Facial: long narrow face, high nasal bridge, pointed nose with cartilages separated at the tip, cleft palate, submucous cleft palate
→ Cardiac: atrial/ventricular septal defects, floppy mitral valve
→ Dental: canine radiculomegaly, delayed dentition, oligodontia, persistent primary teeth, variable root length
If the canines have v long roots (due to no apoptosis of HERS), there may be issues if the tooth must be extracted as it may fracture
What is STHAG?
Selective tooth agenesis - having fewer teeth than normal
What are the types of STHAG?
Anodontia
Hypodontia = <6 teeth are absent
Oligodontia = > 6 teeth are absent
Is syndromic or non-syndromic hypodontia more common?
Non-syndromic
What is Bolk’s terminal line reduction theory?
Hereditary trait - ‘last in each series of teeth tends to be more commonly missing’
What molecular signalling pathways may regulate tooth number?
WNT family
Ectodysplasin A (EDA)
What might mutations of WNT antagonists cause?
AXIN2 - tooth agenesis
APC - Gardner’s syndrome, supernumerary teeth
Syndromic hypodontia - what diseases may hypodontia be associated with?
Ectodermal dysplasia
Cleft palate
Down syndrome
Axenfeld-Rieger syndrome
What is ectodermal dysplasia and what does it cause?
X-linked, autosomal recessive; ectodermal components affected: smooth dry skin, absent sweat glands -> hyperthermia, anodontia (total/partial), conical cuspids and molars, hypotrichosis (lack of hair)
Where do most supernumary teeth occur?
Maxilla
What are the most common supernumaries?
Mesiodens > 4th molars > upper laterals > lower 2nd premolars
What syndromes can cause hyperdontia?
Cleidocranial dysplasia
Gardner’s syndrome
Cleft lip/palate
What disturbances in eruption might there be?
Premature teeth which erupt early:
→ Natal teeth: present at birth; neonatal teeth: erupt during the first 30 days after birth
→ Commonly deciduous mandibular central incisors are affected
→ May predispose to premature eruption of permanent teeth
→ May also induce irritation of the mucosa/ulceration of ventral surface of tongue
→ Premature loss of teeth may occur
→ May be associated w hyperthydroidism
What disturbances in the shape of teeth are there?
Dilaceration
Taurodontism
Dens invaginatus (dens in dente, invaginated odontome)
Supernumerary cusps
Cervical enamel projection/enameloma/enamel pearl
Supernumerary roots
Gemination
Fusion
How does dents invaginatus occur?
Invagination of a portion of EO into DP before mineralisation
Upper laterals most commonly affected
What supernumerary cusps are there?
Carabelli cusp
Dens evaginatus
Talon cusp
What is concrescence?
2+ roots united by cementum after root formation (unlike fusion which occurs during development)
How does concrescence occur and which teeth are most affected?
Due to trauma/crowding
Upper molars more common
