Molar-incisor hypomineralisation

Question 1

what is the definition of hypomineralised?

Answer 1

disturbance of enamel formation resulting in a reduced mineral content but normal shaped teeth

Question 2

what is MI hypomineralisation?

Answer 2

hypomineralisation of systemic origin of 1-4 permanent molars, frequently associated with affected incisors

Question 3

what is the definition of hypoplastic? what are the two different types?

Answer 3

reduced bulk or thickness of enamel
* true - enamel never formed
* acquired - post-eruptive loss of enamel bulk

Question 4

what are the best clinical guidelines for clinicians for MIH in children?

Answer 4

EAPD guidance

Question 5

what is the difference between normal teeth and MIH teeth in terms of pulpal innervation, immune cells and vascularity?

Answer 5

• significant increases in neural density in the pulp horn and subodontoblastic region of MIH teeth - so more sensitive
• significant increases in immune cell accumulation in MIH teeth
• significant increase in vascularity in sensitive MIH samples so increased immune cell activity

Question 6

what are the pain mechanisms for MI hypomineralisation?

Answer 6

• dentine hypersensitivity: porous enamel or exposed dentine facilitates fluid flow within
• peripheral sensitivity: underlying pulpal inflammation leads to sensitisation of C-fibres
• central sensitivity: from continued nociceptive input?

Question 7

why is it hard to determine aetiology of MIH?

Answer 7

• uncrlear diagnostic criteria in classification
• most parents can’t remember details from 8-10 years before
• variations in quality and completeness of case records
• small study populations

Question 8

when is the critical period for formation of MIH?

Answer 8

• first year of life
• enamel matrix of crown of FPMs is complete by one year
• ask about period from 3rd trimester of pregnancy to 2 years as this is when enamel formation occurs

Question 9

what are the 3 clinical periods of enquiry?

Answer 9

1. pre-natal - general health in 3rd trimester of pregnancy (pre-eclampsia, gestational diabetes)
2. natal - birth trauma / annoxia or pre-term birth
3. post-natal - fever and medication, socioeconomic status, rural vs. urban

Question 10

what illnesses in the first 2 years of life could cause MIH?

Answer 10

• measles
• rubella
• chicken pox (varicella)

Question 11

what are the clinical problems with MIH?

Answer 11

• loss of tooth substance
• breakdown of enamel - sensitivity (thin enamel or exposed dentine)
• toothwear - dentine more soft
• appearance

Question 12

what are the treatment options for hypomineralised molars?

Answer 12

• composite / GIC restorations
• stainless steel crowns
• ahdesively retained copings
• extraction (8.5-9.5 years)
• GC tooth mousse - rub on hypomineralised teeth for sensitivity

GIC placed on post-eruptive breakdown

Question 13

when extracting hypomineralised first permanent molars, what should you consider?

Answer 13

• age
• skeletal pattern
• future orthodontic needs
• quality of teeth e.g. caries

Question 13

why should you consider age when extracting hypomineralised first permanent molars?

Answer 13

wait until 8.5-9.5 years as the 7s will come in and can replace the 6s once removed due to physiological mesial drift - look for calcification of the birfurcation of the 7 on radiographs

Question 14

what are the treatment options for hypomineralised incisors?

Answer 14

• acid pumice microabrasion (removes 150um of enamel)
• resin infiltration (on white spots)
• external bleaching
• localised composite placement
• combination of above
• full composite veneers

resin infiltration