Dentinogenesis Imperfecta and Amelogenesis Imperfecta Flashcards
What is dentinogenesis also known as? (1)
Hereditary opalescent dentine
What is the prevalence of dentinogenesis imperfecta? (1)
1/8000
What is the inheritance for dentinogenesis imperfecta? (1)
Autosomal dominant inheritance – Ch4 & DSPP gene mutation
Which dentitions are more affected in dentinogenesis imperfecta? (1)
Primary > Secondary affected
What are the two types of dentinogenesis imperfecta? In what syndrome can dentine changes also be seen? (3)
- Type I – associated with Osetogenesis Imperfecta (OI) (collagen type I gene mutation Ch7 or Ch17)
- Type II – teeth only affected (Ch4)
- Can see dentine changes in Ehlers Danlos Syndrome (collagen type I mutation)
Summarise Osteogenesis Imperfecta (5)
- Fragile bones – Hx of fractures from mild trauma like walking into furniture
- Blue sclera
- Deafness (normal hearing in childhood but deafness develops >30s)
- Lax ligaments around joints
- Patient may have dentine changes subtle>severe
What are the clinical features of Dentinogenesis Imperfecta? (6)
- Teeth are opalescent with grey or brown colouring
- Severity varies even within the same family
- Enamel may chip easily – attrition (can be to gingival level in primary dentition) & pulpal exposure
- May have obliterated pulps – initially pulps are large but steadily obliterated by haphazard abnormal dentine deposits (normal dentine around ADJ)
- Bulbous crowns
- Short, thinner roots
Draw a table to describe the differences in radiographic appearance of AI and DI (6,5)
Amelogenesis Imperfecta
- Thin/absent enamel (or normal thickness)
- AOB, multiple open contacts
- Failure of permanent denition eruption
- Taurodontism
- Radiopacity of enamel = dentine
- Permanent dentition affected more than primary dentition
Dentinogenesis Imperfecta
- Bulbous molar crowns
- Initially large pulps (flame shaped) that becomes obliterated
- Short roots
- Shell teeth (type III DI) enormous pulps = very thin dentine
- Primary dentition affected more than permanent dentition
What is Amelogenesis Imperfecta? (1)
Defect in enamel development
Which dentitions are affected in Amelogenesis Imperfecta? (2)
- Primary and secondary teeth affected
- Primary dentition affected more than permanent dentition
What is the prevalence of Amelogenesis Imperfecta? (1)
Varies from 1/700 (Sweden) to 1/14000 (USA)
How is Amelogenesis Imperfecta classified? (2)
- By the type of defect (phenotype)
- Mode of inheritance or part of a syndrome (e.g. nephrocalcinosis)
What are the three phenotypes in Amelogenesis Imperfecta? (3)
- Hypoplastic
- Hypocalcified
- Hypomaturation
What are the clinical features and common genetic inheritance of the Hypoplastic phenotype of Amelogenesis Imperfecta? (3)
- Decreased quantity of enamel
- Thin enamel – smooth, pitted or rough
- Most autosomal dominant
What are the clinical features and common genetic inheritance of the Hypocalcified phenotype of Amelogenesis Imperfecta? (6)
- Dull, opaque enamel
- White, honey or brown
- May break down rapidly
- Increased sensitivity
- Increased deposits of calculus
- Most autosomal dominant
What are the clinical features and common genetic inheritance of the Hypomaturation phenotype of Amelogenesis Imperfecta? (3)
- Mottled or frosty white
- Opaque
- Sometimes incisal ½ “snow-capped teeth”
What are the types of inheritance patterns of Amelogenesis Imperfecta? (4)
- Autosomal Dominant
- Autosomal Recessive
- X-Linked
- Can be sporadic
Describe the inheritance and associated clinical features in Amelogenesis Imperfecta Autosomal Dominant inheritance pattern (9)
- F>M
- 2 > 1 dentition
- 50% pass to offspring
- CH4 enamelin gene mutation (e.g. ENAM, AMELEX)
- Up to 50% AOB, taurodontism in some
- Enamel thin and hard (Hypoplastic)
- Enamel difficult to see on rads
- Some have normal thickness but abnormal translucency and decreased mineralisation
- Tricho-dento-osseous syndrome (AI, taurodontism, curly hair, bone changes)
Describe the inheritance and associated clinical features in Amelogenesis Imperfecta Autosomal Recessive inheritance pattern (6)
- Blood relatives e.g. 1st cousins
- Both parents can be affected or unaffected carriers
- 25% offspring inherit 2 copies of mutated genes
- Uncommon (increased in Polynesia)
- Gene on Ch2 associated with ocular defects
- Hypoplasia +/- hypomineralisation “pigmented enamel
Describe the inheritance and associated clinical features in Amelogenesis Imperfecta X-linked inheritance pattern (6)
- Affects F (XX) and M (XY)
- Mutation amelogenin gene on X-Ch
- No F to M transmission
- F receives 2x X-Ch so all daughters inherit
- Varying severity
- Heterzygote F pass on maturated gene to F and M
What are the treatment aims in Amelogenesis Imperfecta? (4)
- Prevention – OHI, fluoride, diet counselling, fissure sealants
- Aesthetics – microabrasion, composites (direct or indirect)
- Reduce sensitivity – composites, full coverage crowns
- Prevent further tissue loss – fissure sealants, composites, gold onlays on posterior teeth, PFM crowns on young uncooperative patients
