Developmental Dental Abnormalities

Question 1

Give some conditions associated with hypodontia

Answer 1

Ectodermal dysplasia

Downs

Cleft palate

Hurlers syndrome

Question 2

What is often a large restorative problem when maxillary laterals are missing

Answer 2

Overeruption of mandibular canines

Question 3

What are some abnormalities of tooth shape and size?

Answer 3

Microdont - peg lateral

Macro don’t

Double teeth
- gemination - one tooth splits into two
- fusion - two teeth fuse into one

Odontomes

Taurodontism - flame shaped pulp

Dilaceration of crown or rooth

Talon cusp - extra cusp

Question 4

What is dens in dente?

Tx?

Answer 4

‘Tooth within a tooth’

Invagination of the tooth enamel and dentine into the pulpal chamber

Treatment includes immediately sealing off invaginations to prevent bacterial ingress

Question 5

What anomalies of root structure may occur?

Answer 5

Short root anomaly - permanent max incisors, often canines and premolars too

Radiotherapy

Dentine dysplasia

Accessory roots

Question 6

What may cause some enamel defects?

Answer 6

Amelogenesis imperfecta

Environmental enamel hypoplasia

Localised enamel hypoplasia

MIH

Question 7

What are the main forms of amelogenesis imperfecta?

Answer 7

Hypoplastic

Hypo calcified

Hypomaturational

Mixed forms

Question 8

What is hypoplastic amelogenesis imperfecta

Presentations?

Answer 8

Thin or insufficient enamel formation leading to teeth that appear smaller and are more susceptible to toothwear and damage

Enamel is often roughed, pitted or grooved giving teeth a yellow or discoloured appearance

Enamel crystals do not grow to the correct length

Question 9

What is hypocalcified amelogenesis imperfecta?

Presentations?

Answer 9

Enamel is formed but is soft but poorly calcified making it easily worn away

Tooth typically chalky and susceptible to wear and pathology

Enamel crystals do not grow to correct thickness or width

Question 10

What is hypomaturational amelogenesis imperfecta?

Answer 10

Enamel not matured properly leading to translucent/opaque or cloudy enamel with white or brown discolourations

Enamel generally harder than in hypocalcified

Enamel crystals grow to correct length, but incorrect width or thickness and have poor mineralisation

Question 11

What is mixed form amelogenesis imperfecta?

Answer 11

Characteristics of multiple types of AI are presenting

Question 12

Give some possible causes of enamel hypoplasia

Answer 12

Systemic illness such as liver or kidney failure

Poor nutrition during development

Infection - measles

Turners hypoplasia
- periapical infection or trauma
- to primary tooth

CONGENITAL SYPHILLIS!
- HUTCHINSONS incisors

Question 13

What are the main causes of localised hard tissue defects?

Answer 13

1 - trauma

2 - caries

3 - abscess of primary tooth

Question 14

How would one treat fluorosis?

Answer 14

Micro abrasion therapy

Veneers

Vital bleaching

Question 15

Give some prenatal causes of generalised environmental enamel defects

Answer 15

Rubella

Thalidomide

Fluorosis

Congenital syphilis

Cardiac and kidney disease

Question 16

Give some neonatal causes of generalised environmental enamel defects

Answer 16

Premature birth

Meningitis

Question 17

Give some postnatal causes of generalised environmental enamel defects

Answer 17

Measles
Chickenpox
TB
Pneumonia
/ infectious diseases

Vitamin deficiency

Heart disease

Question 18

How would make a diagnosis of AI?

Answer 18

Familial inheritance - take a family history

Generally affects both dentitions

Affects all teeth and their size, structure and colour

Take radiographs

Question 19

Problems / signs / symptoms of AI?

Answer 19

Sensitivity

Caries / acid susceptibility

Poor aesthetics

Poor oral hygiene

Delayed eruption

Anterior open bite

Question 20

3 types of dentinogenesis imperfecta?

Answer 20

Type 1 - with osteogenesis imperfecta ‘brittle bone disease’

Type 2 - autosomal dominant - gene linked - not on sex chromosome

Brandywine

Question 21

What is type 1 dentinogenesis imperfecta?

Problems?

Answer 21

Associated with osteogenesis imperfecta

• translucent blue / grey hue of teeth
• normal enamel but discoloured and poorly formed dentine beneath

Rapid wear, chipping and breaking of tooth and also bulbous crown appearance

Question 22

What is type 2 dentogenesis imperfecta

Answer 22

Dentin formation affected due to mutations in odontoblasts

No association to OI

Brown / blue opalescence of teeth

Defects in structure of dentine leading to teeth susceptible to wear, bulbous crowns, pulpal obliterations etc

Question 23

Give some abnormalities of cementum and what they are

Answer 23

Cleidocranial dysplasia
- hypoplasia of cellular component of cementum

Hypophosphatasia
- hypoplasia or aplasia of cementum
- early loss of primary teeth

Question 24

Why may delayed eruption of teeth occur?

Answer 24

Malnutrition

Low birth weight

Downs

Hypothyroidism

Gingival hyperplasia

Question 25

Why may premature exfoliation occur?

Answer 25

Trauma Following pulpotomy Hypophosphatasia

Question 26

Why may delayed exfoliation occur?

Answer 26

Infra occlusion of teeth ‘Double’ primary teeth Hypodontia Ectopic permanent successor Trauma

Question 27

Diagnose

Answer 27

Taurodontism - body of tooth enlarged at expense of root

Question 28

Diagnose

Answer 28

Dens in dente

Question 29

What is MIH?

Answer 29

Molar Incisor Hypomineralization (MIH) is a qualitative developmental dental defect that affects the enamel of permanent molars and incisors

Question 30

What is mild MIH?

Answer 30

Demarcated opacities located at non-stress bearing areas No caries associated with affected enamel No hypersensitivity Very mild or no incisor involvement

Question 31

What is moderate MIH?

Answer 31

Demarcated opacities present on both molars and incisors Post-eruptive enamel breakdown is limited to one or two surfaces without cuspal involvement Normal dental sensitivity May require atypical restorations

Question 32

What is severe MIH?

Answer 32

Post eruptive enamel breakdown Crown destruction Caries associated with affected enamel History of dental sensitivity and aesthetic concerns

Question 33

What is enamel hypoplasia?

Answer 33

Quantitative defect with reduced enamel thickness - smooth borders of enamel indicating developmental and pre-eruptive lack of enamel

Question 34

Most common clinical problems with MIH?

Answer 34

Enamel breakdown leading to dentine exposure - risk of pulpal involvement Tooth sensitivity - can lead to poor oral hygiene as less likely to perform measures Aesthetic issues on incisors Dental fear / anxiety from tx Sharp enamel due to shearing of poorly mineralised enamel

Question 35

What are thought to be the causes of MIH?

Answer 35

Acute or chronic illness during eruption Exposure to environmental pollutants Genetically impacted Frequent childhood illness

Question 36

What defects occur at the bud stage?

Answer 36

Congenitally missing teeth Supernumerary teeth - dependant on number of placodes

Question 37

Which DDAs occur at the cap stage?

Answer 37

Cyst Odontoma Gemination Fusion Dens in dente

Question 38

What occurs at the bell stage? What DDAs occur at the bell stage?

Answer 38

HISTODIFFERENTIATION - formation of ameloblasts and odontoblasts - from inner and outer enamel organ Morphodifferentiaiton - crown shape and size - macro/microdontia Apposition - ameloblasts and odontoblasts start depositing - enamel hypoplasia, enamel pearls Amelogenesis imperfecta Dentogenesis imperfecta

Question 39

What occurs after cap stage? Which DDA’s?

Answer 39

Maturation (4-5 years to complete) - long time so illness can affect these ones - deposition of enamel and dentin - calcification of crown DDAs - enamel hypomineralisaiton - fluorosis - tetracycline staining

Question 40

What are the cells of the tooth germ?

Answer 40

Enamel organ - ameloblasts Dental papilla - odontoblasts - pulp cells Dental follicle - cementoblasts - Osteoblasts - alveolar bone - fibroblasts - PDL

Question 41

What is AI?

Answer 41

Intrinsic alteration of enamel - hereditary - autosomal dominant, recessive or X-linked - effects both dentitions - thin to no enamel

Question 42

What is DI?

Answer 42

Autosomal dominant intrinsic alteration of dentine - resulting in bulbous crowns - short roots - obliterated pulps

Question 43

What is enamel pearl?

Answer 43

Chunk of enamel blocking attachment of sharpens fibers - automatic periodontal pocket - wont remove with PMPR - only in molars