MIH Flashcards

1
Q

What is MIH?

A

A clinical diagnosis to describe hypomineralisation of systemic origin of one or more of the four permanent first molars frequently associated and affected incisors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the prevalence of MIH?

A

3.6-25%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How does MIH present?

A

Affecting one or more first permanent molars and/or incisors
Demarcated patches
White-brown, cream
Post-eruptive breakdown
Missing 6’s due to early XLA
Heavily restored/abnormal restorations
Calculus as brushing is not comfortable for these children

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Differential diagnosis

A

Fluorosis - increased F content of water
Amelogenesis imperfecta - family history or sporadic mutation
Chronological hypomineralisation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What age is the diagnosis made?

A

7-9 years

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

When does tooth formation begin?

A

6w iu

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

When do 1st molars begin to calcify?

A

4/12 iu and calcify at birth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

When do central incisors and lower laterals start forming?

A

3-4/12 iu

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

When do upper laterals start forming

A

10-12/12 iu

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How is amelogenesis affected?

A

Secretory phase
- defines the form of the tooth
- deposition of organic matrix plus small thin crystallites
- incremental growth in thickness
- not a continuous process

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Describe enamel hypoplasia

A

Disruption in secretory phase
Early in developmental process
Small pits and grooves
Gross enamel surface deficits

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Describe how the maturation stage is affected?

A

Establishes quality of the tooth
Degradation of the organic matrix
Further remineralisation
Ameloblasts move Ca and PO4
Process continues post eruption
Apoptosis of the ameloblasts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Underlying causes of MIH

A

Insult to enamel formation from around 37w to 3y
Transitional and maturation phase of enamel is effected - may be reversible damage to ameloblasts with qualitative disturbances to enamel formation
Protein retention and poor crystal formation
Can be produced experimentally in rats with conditions of low pH and low Ca and phosphate ability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What has been disrupted in maturation phase?

A

Hypomineralisation - disruption in maturation phase
poor mineralisation of matrix
happens later in development
White/brown opacities
normal thickness but dubious quality of enamel

(altered calcium/phosphate ratio, less distinct enamel rods, bacterial penetration of enamel, lower hardness of enamel)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How does this happen?

A

Timing of insult
Pyrexia
Hypocalcaemia
Hypoxia of mother/child

(exposure to chemicals, peri-natal/neonatal problems/ common childhood illnesses and medically compromised children)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Common childhood illnesses causing MIH

A

Rest issues, otitis media
Coeliac, renal disease and CF

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Appearance as a challenging factor

A

Appearance to parents and children
Transition to secondary school
Managing expectations

18
Q

Challenges - sensitivity

A

Greter innervations in subodontoblastic pulp horn/regions
increased immune cell density
increased vascularity in sensitive teeth
porous enamel - exposed dentine
activation of A delta fibres
Underlying increase of c-fibre action (peripheral sensitisation)

19
Q

Restorative factor challenges

A

Site, colour, bonding, caries devo, poor prognosis, immature dentine, difficult to anaesthetise, crumbly, over-eruption of upper molars

Restorations tend to fail 2x by the age of 9y

20
Q

Prevention methods

A

Fluoride, desensitising toothpaste, CPP-ACP products (casein phosphopeptide, amorphous calcium phosphate)
FS
OH

21
Q

Temporisation methods

A

GIC
Fill in defects
SSC

22
Q

Restore or extract?

A

Depends on extent of damage
Consider structure of enamel
Age
Presence of adjacent teeth
Occlusal/orthodontic factors

23
Q

Preferable restoration methods

A

Composite
Gold/CoCr only

THEN SSC
FGC useful in growing years to maintain space and eruption of other teeth

24
Q

Benefits of SSCs

A

Good longevity
Easy to fit
Separators
Occlusal dimension settles
Gingival health
Erupting 7s

25
Q

Benefits of fabricated onlays

A

Well tolerated
Fantastic longevity
Considered permanent

Disadvantages - lab bill and time

26
Q

When to extract

A

Poor prognosis teeth
Age - furcation on L7s on DPT
- if XLA of 6 too early, 5 tips, if XLA too late, 7 tips
- Consultation with orthodontist

27
Q

What is balancing?

A

XLA of tooth in opposite side of arch to prevent a centreline shift

28
Q

What is compensating?

A

XLA of tooth in opposing quadrant to precent overeruption

29
Q

Rules for class 1 molars

A

compensate - balance if crowded

30
Q

Rules for class 2 molars

A

Min crowding, extract U6 is likely to over erupt, maintain until 7 erupts if not.

No balancing needed in min crowding

In crowding: compensate if U6 is likely to over erupt, remove before or after 7s erupted. No balancing neede

31
Q

Rules for class 2 molars

A

Min crowding, extract U6 is likely to over erupt, maintain until 7 erupts if not.

No balancing needed in min crowding

In crowding: compensate if U6 is likely to over erupt, remove before or after 7s erupted. No balancing needed

32
Q

Class 3 rules

A

Orthodontic advice to be sought. Avoid balancing and compensation

33
Q

Tx of incisors

A

Survey
Review
Consider pt factors
Repair aesthetics
- microabrasion
- etch, bleach, seal
- bleach
- composite
- bleach and composite

34
Q

How does microabrasion work?

A

Discolouration for outer layer of enamel
Rubber dam
HCl and pumice -> slurry
Rubber cup
Polish for 5s
up to 10, 5s appls
Polish teeth and use fluoride toothpaste

35
Q

Etch-bleach and seal method

A

60s etch
Bleach 5% NaOCl 5-10m
Re-etch and apply clear FS

36
Q

Advantages of XLA of 6s

A

Immediate resolution of symptoms/infection
One off procedure with favourable cost/benefit ratio
Space created may be useful to alleviate crowding, reduced overjet, create space for eruption of 8s

37
Q

Disadvantages of XLA of 6s

A

loss of permanent tooth
may necessitate sedation/GA
consequences of early/late XLA
ortho tx - time and complexity

38
Q

What is the ideal time to remove the 6s?

A

Root bifurcation of 7s forming
8-10y/0 (dental age 9)

39
Q

Adv/disdv of temporising with GIC

A

Tolerant of moisture contamination
F release
Easy to place
Poor physical properties
No full coverage - does not help with hypersensitivity

40
Q

Adv/disadv temporising with SSC

A

Prevents further breakdown
Relieves sensitivity
Longevity
Relatively quick and inexpensive
Single visit

Can be more technically challenging
LA often required
Monitor eruption of 7s - potential impaction
Occlusion