Anomalies (including Numerical, Enamel and Dentine Defects)

Question 1

What are the most commonly missing teeth ?

Answer 1

3rd molars
Lateral incisors
Lower premolars (5s).

Question 2

What are most likely to be missing - permanent vs. primary teeth ?

Answer 2

Permanent.

Question 3

What two teeth in the permanent dentition are least likely to be missing ?

Answer 3

First permanent molars.
Upper central incisors.

Question 4

What are examples of conditions which cause a predisposition to hypodontia ?

Answer 4

Ectodermal dysplasia.
Down syndrome.
Cleft palate.
Hurler’s syndrome.

Question 5

Is hyperdontia more common in males or females ?

Answer 5

Males

Question 6

Is hyperdontia more common in maxilla or mandible ?

Answer 6

Maxilla

Question 7

What medical condition causes predisposition to hyperdontia ?

Answer 7

Cleidocranial dysplasia.

Question 8

What are the four types of supernumerary teeth ?

Answer 8

Conical.
Tuberculate.
Supplemental.
Odontome.

Question 9

Define an odontome.

Answer 9

Irregular mass of dental hard tissue, compound or complex.

Question 10

Name some examples of dental anomalies associated with size and shape of the teeth.

Answer 10

Microdontia.
Macrodontia.
Double teeth.
Odontomes.
Taurodontism.
Dilaceration of crown or root.
Accessory cusps.
Peg laterals.

Question 11

What are three potential causes of short root anomaly ?

Answer 11

Radiotherapy.
Dentine dysplasia.
Accessory roots.
Asian populations.
Downs syndrome.

Question 12

What tooth is most likely to be affected by short root anomaly ?

Answer 12

Permanent maxillary incisors.

Question 13

Name three general enamel anomalies ?

Answer 13

Amelogenesis imperfecta.
MIH.
Environmental/localised enamel hypoplasia.

Question 14

What are two causes of localised enamel hypoplasia ?

Answer 14

Trauma.
Infection of primary predecessor.

Question 15

What are the four causes of environmental enamel hypoplasia ?

Answer 15

Systemic.
Nutrition.
Metabolic - Rhesus incompatibility, liver disease.
Childhood infection - measles.

Question 16

What are the four main forms of amelogensis imperfect ?

Answer 16

Hypoplastic.
Hypocalcified.
Hypomaturational.
Mixed forms.

Question 17

How might a hypomineralised tooth present ?

Answer 17

With white, yellow or brown lesions.
All tooth tissue present.

Question 18

Define hypomineralisation.

Answer 18

Under mineralised tooth with normal tooth structure.
Secretory phase unaffected.
Mineralisation phase disrupted.

Question 19

Define hypoplastic.

Answer 19

Abnormal tooth structure with normal mineralisation.
Secretory phase disrupted.
Mineralisation is normal.

Question 20

What is examples of environmental generalised hard tissue defect ?

Answer 20

Fluorosis
MIH

Question 21

How can fluorosis be treated ?

Answer 21

Microabrasion.
Composite veneers.
Vital bleaching.

Question 22

What causes fluorosis ?

Answer 22

Over-exposure to fluoride.

Question 23

What might cause MIH ?

Answer 23

Childhood illness - liver or kidney failure.

Question 24

What are examples of pre-natal conditions which can lead to generalised environmental enamel defects ?

Answer 24

Rubella.
Congenital syphilis.
Cardiac and kidney disease of mother.

Question 25

What are examples of neo-natal conditions which can lead to generalised environmental enamel defects ?

Answer 25

Prematurity. Meningitis.

Question 26

What are examples of post-natal conditions which can lead to generalised environmental enamel defects ?

Answer 26

Otitis media. Measles. Chickenpox. TB. Pneumonia. Deficiency of Vit A, C and D. Heart disease.

Question 27

What is the timeline of post-natal period ?

Answer 27

8 weeks to 2 years.

Question 28

What is the timeline of neo-natal period ?

Answer 28

0-8 weeks.

Question 29

What type of genetic condition is amelogenesis imperfeca ?

Answer 29

Familial inheritance. Autosomal dominant, recessive and x-linked.

Question 30

Define hypoplastic type of amelogenesis imperfecta.

Answer 30

Enamel crystals do not grow to correct length.

Question 31

Define hypomineralised type of amelogenesis imperfecta.

Answer 31

Crystallites fail to grow in thickness and width.

Question 32

Define hypomaturational type of amelogenesis imperfecta.

Answer 32

Enamel crystal grow incompletely in thickness or width but to normal length with incomplete maturation.

Question 33

What are the main consequences of amelogenesis imperfecta ?

Answer 33

Sensitivity. Caries/acid susceptibility. Poor aesthetics. Poor OH. Delayed eruption. Anterior OB malocclusion.

Question 34

What are some of the tx options for patients with amelogenesis imperfecta ?

Answer 34

Preventative therapy. Composite veneers. Fissure sealants. Metal onlays. SSC. Orthodontics.

Question 35

Name examples of systemic disorders which are associated with enamel defects (not amelogenesis imperfecta).

Answer 35

Down syndrome. Prader-Willi. Porphyria. Pseudohypoparathyroidism.

Question 36

What is MIH ?

Answer 36

Developmental condition related to disruption of enamel formation during third trimester and first year of life. Qualitative defect of enamel affecting FPMs and incisors. Causes unsymmetrical half white/yellow/brown lesions on teeth.

Question 37

MIH - when is the enamel matrix of FPMs complete by ?

Answer 37

1 year old.

Question 38

MIH - when is the enamel matrix of permanent incisors complete by ?

Answer 38

2 years old.

Question 39

What are the characteristics of enamel formation and mineralisation of a tooth affected by MIH ?

Answer 39

Normal amount of enamel and tooth shape. Reduced mineralisation.

Question 40

MIH - what phases of tooth development are affected ?

Answer 40

Secretory phase is unaffected. Amelogenesis is affected i.e. abnormal mineralisation phase.

Question 41

What are the potential causes of MIH ?

Answer 41

Birth trauma. Childhood illness in first year of life. Mother illness in final trimester. Medications taken in first year of life. Socioeconomic status. Prolonged breastfeeding.

Question 42

What are the dental consequences of MIH ?

Answer 42

Accelerated toothwear, caries formation. Sensitivity. Aesthetics. Problems with dental material bonding.

Question 43

For FPMs affected by MIH, what are the treatment options ?

Answer 43

SS crown placement. - where severe lesions. XLA at bifurcation calcification of SPMs - where severe lesions. Composite restoration or GIC restoration - where mild/localised lesions. Topical fluoride application - where mild.

Question 44

For permanent incisors affected by MIH, what are the treatment options ?

Answer 44

Acid pumice microabrasion - localised lesions. Resin infiltration - localised lesions. External bleaching. Localised composite restorations. Composite/porcelain veneers after 20 years old.