molar incisor hypomineralisation

Question 1

What is MIH?

Answer 1

Hypomineralisation of systemic origin of 1-4 first permanent molars, frequently associated w affected incisors

Question 2

What is the difference between hypomineralisation and hypoplasia?

Answer 2

Hypomineralisation- qualitative disturbance in enamel formation

Hypoplasia- quantitative dist..

Question 3

How does MIH present clinically?

Answer 3

Well demarcated white-yellow or brown-yellow enamel opacities
1-4 FPMs may be affected
Severe- defective enamel lost soon after eruption, incisors also affected but enamel not lost for these

Question 4

What is the global prevalence of MIH?

Answer 4

13%

Question 5

What is the aetiology of MIH?

Answer 5

PRENATAL factors (9% of cases)
Maternal pyrexia
Meds (antibiotics)
Prolonged vomiting
Maternal diabetes
Vit D deficiency

(FPMs start to mineralise just before birth)

PERINATAL factors (34%)
Caesarian section
Prolonged/complicated delivery
Premature/low birth weight
Twins

POSTNATAL (34%)
ENT/resp problems
Pyrexia
Seizures
Urinary infections
Antibiotics

MOSTLY associated w hypocalcaemia and hypoxia
Maybe genetics?
Maybe environmental pollutants?
Increased prevalence in twins (esp monozygotic)

Question 6

What are lab studies of MIH?

Answer 6

ENAMEL
Porous, weak, poor etch pattern, high protein content, low calcium:phosphate

DENTINE
Sparse reparative dentine and irregular globular, influx of bacteria in tubules

PULP
Underlying chronic pulp inflam, increased immune cells, vascularity and neural density

Question 7

What are patient related factors?

Answer 7

Extreme tooth sensitivity
Aesthetic concerns (self esteem, bullying)
Anxiety to dental tx
Need for long term intervention (financial)

Question 8

What are clinical related factors?

Answer 8

Difficulty in achieve adequate level of anaesthesia
High failure rate for adhesive/sealants
Tooth tissue loss
High caries experience

Question 9

What is the holistic care for MIH?

Answer 9

1. Prevent, remineralise, alleviate symptoms
2. Tx plan for FPM
3. Improve incisor aesthetics
4. Child centred approach

Question 10

What is tooth mousse?

Answer 10

Water based, sugar free, dental topical cream containing CPP-ACP

Delivers calcium and phosphate ions

Daily application in trays or locally

May improve sensitivity/symptoms/appearance/structure

Question 11

Are fissure sealants recommended?

Answer 11

High failure rates (26% survival at 4 yrs)
High sensitivity and extra saliva do difficult
Preuse of 5% sodium hypochlorite to remove protein content
Use warm water and cotton pledgets
Avoid aspirator
Used light cured GI sealants

Question 12

What are tx options?

Answer 12

1. Prevent/review- fluoride, tooth mousse, fissure seal
2. Restore- adhesive, PMCs, lab formed crowns
3. Extract (LA/IS/GA), ortho, compensating?

Question 13

What should you do about FPMs of poor prognosis?

Answer 13

X at optimum stage of dental development (9-11yrs)- 7s unerupted but furcation starting, 8s visible
Class II- maintain upper FPMs until 7s erupt
Class III- try to restore

Question 14

When do you need to get an ortho opinion?

Answer 14

Class II/III cases
Hypodontia
Severe crowding

Question 15

What are materials that can be used to restore PMCs?

Answer 15

RMGICs (short term proof definitive/x)
Composite resin (only for mild w no cuspal involvement)
PMCs (esp 2-5yrs)
Cast onlays/crowns

Question 16

What are the advantages of PMCs?

Answer 16

Prevent further tooth deterioration/decay
Controls sensitivity
Establish correct interproximal contacts and occlusal relationships
Not technique sensitive
Quick and cheap

Question 17

What are disadvantages of PMCs?

Answer 17

Adverse reactions w nickel allergies
AOB if not fitted well
Gingival inflam
Not permanent

Question 18

When should you do cast restorations?

Answer 18

Indirect gold onlays
When maintenance of FPM indicated long term
Late mixed or early permanent dentition

Conventional full crowns avoid- immature teeth have short crowns, large pulps and the prep is highly destructive

Question 19

What are tx options for incisors?

Answer 19

Tooth whitening
Composite resin
Micro abrasion
Resin infiltration (ICON)

Question 20

What should you do before you start tx to incisors?

Answer 20

Ask child what actually concerns them
Assess colour, tooth tissue loss and sensitivity
Good clinical photos and SHADE pre/post
Written consent

Question 21

How does tooth whitening work?

Answer 21

Hydrogen peroxide or 10% carbamide peroxide gel
Free radicals diffuse in and react w coloured organic pigments to create less pigmented molecules which reflect less colour
Some post op sensitivity

Question 22

How do we use tooth whitening?

Answer 22

10% carbamide peroxide gel nightly in custom trays which breaks down to 3.6% hydrogen peroxide (Ultradent)
2-4 weeks, then review
Written (child friendly) instruction and written consent

Illegal to use >0.1% hydrogen peroxide under 18yrs unless tx or preventing disease
Can’t use >6% under 18yrs

Usually wait til 13 for occlusion to come through

Question 23

What is microabrasion?

Answer 23

Hydrochloric acid and mechanical removal of intrinsic and superficial enamel stain
(6.6% HCL slurry w silicon carbide micro particles)

Safe, effective, conservative, simple, economical

Doesn’t work for tetracycline staining or dentinogenesis imperfecta

Question 24

What could go wrong with microabrasion?

Answer 24

Severe extrinsic staining (food colours)- remedial bleaching

Question 25

What is resin infiltration?

Answer 25

Isolate w rubber dam
Apply ICON-etch (15% hydrochloric acid) for 2 mins
Remove etch and rinse for 2 mins
Apply ICOM-dry for 30s (3-4x)
Apply ICON-infiltrant for 3 mins
Remove excess
Light cure 40s
Polish

Penetrates 40 microns, so if want tooth whitening in future, sof lex

Question 26

What are the problems with composite resin restorations?

Answer 26

High risk of bond failure with defective dentine/enamel