MIH Flashcards

1
Q

Which cells form enamel?

A

ameloblasts

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

what is the stimulus that triggers ameloblasts to form enamel ?

A

dentine deposition

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

what happens when ameloblasts are triggered?

A

they secrete matrix proteins and then they become calcified to about 20% (initial calcification)

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

what function change do ameloblasts go through after the matrix proteins secretion phase?

A

they secrete enzymes which remove organic component and allows full mineralisation to 99% (maturation stage)

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

How does removing the organic content allow full mineralisation?

A
  • the crystals are trying to expand and the organic component is takin gum loads if room and preventing the expansion (Maturation stage) = 99% mineralisation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

which three stages do we see problems occurring ?

A
  1. secretion of matrix proteins
  2. calcification stage
  3. maturation stage
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what happens when you have a disruption during the laying down of the enamel matrix

A

HYPOPLASTIC DEFECT due to ….
- physical disruption
- less enamel matrix
- matrix will be mineralised normally but we will have less of it
- reduced bulk or thickness of enamel
- enamel never formed

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

what happens if the problem occurs in early initial calcification stage or maturation stage?

A

HYPO MINERALISATION due to…
- disturbance of enamel formation therefore reduced mineral content
- less mineral in enamel therefore less calcification
- AKA hypocalcifiaction or hypo maturation

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

how can enamel defects be classified?

A

systemic or local

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

List the different ways in which we can get local enamel defects.

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

list the different ways which we can get systemic enamel defects.

A
  • environmental
  • genetic = amelogenic imperfecta
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what can environmental defects be further classified into?

A
  1. CHRONOLOGICAL = this defect has occurred at a very specific point in time as that enamel forms therefore specific teeth are affected. eg. MIH
  2. GENERALISED = the insult has been there for a longer amount of time eg. fluorosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

how can we describe enamel defects? (3)

A
  1. DEMARCATED = distinct, clear boundary, yellow, white or brown
  2. DIFFUSE = no clear boundary; lines patches
  3. HYPOPLASTIC = loss of enamel, pits and grooves
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Give an eg of demarcated defects?

A

MIH

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

give an eg of diffuse defects?

A

fluorosis

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

Give eg of hypoplastic defects?

A

localised legions

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

give an eg of a condition which have all 3 defects ?

A

ameleogensis imperfecta

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

define MIH?

A

hypo mineralisation of systemic origin of one or more first permanent molars as well as affected incisors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what 2 things are we looking for when diagnosing MIH?

A

demarcation
first permanent molars

20
Q

what are some other terms for MIH?

A
  1. molar hypomineralisation (MH)
  2. incisor hypominerlisation (IH)
  3. deciduous molar hypomineralisation (DMH) (ppl use this term as second primary molars can be affected)
21
Q

list some histological and biochemical analysis of MIH

A
  • abnormal enamel either full thickness or inner enamel only
  • discolouration/ breakdown associated with porosity = MOST porous
  • brownish/ yellow - LESS porous
  • carbon concentration higher in affected enamel
22
Q

why Is it important to identify hypo mineralised molars ? (5)

A
  1. these teeth go thru POST ERUPTIVE BREAK DOWN
  2. SENSITIVE
  3. softer so more susceptible to CARIES
  4. DECAY FASTER
  5. DIFICULT TO RESTORE
23
Q

Prevalence of MIH?

A

5-25% in uk

24
Q

what disruption may be the cause of MIH?

A

ameloblast disruption

25
Q

how do we treat?

A
  1. start with molars
  2. what is the long term prognosis
26
Q

how do we judge long term prognosis

A
27
Q

what orthodontic considerations do we need to think about when extracting MIH teeth?

A
28
Q

why is timing important when extracting MIH teeth?

A
  • if we extract at the right time and right age = gives us best chance of the second permanent molars moving forward in to that space
  • lower arch = if we take 6 out when child is aged 8-9 = give us best chance of 7 moving into that space
  • upper arch = timing less critical, space closure likely if extracted before 11/12 yrs
29
Q

what is a compensating extraction?

A

-when we need to extract a lower 6
- upper 6 will over erupt
- even if upper 6 has a good prognosis we would still extract that tooth

THIS DOESNT WORK THE OTHER WAY ROUND (as lower 6’s don’t overerupt)

30
Q

what happens if we decide that these teeth can be restored or maintained?

A
31
Q

when do we use tooth mouse and what are the benefits?

A
  1. use for sensitivity
  2. used at home
  3. pleasant for children
32
Q

when do we use fissure sealant ?

A
  • if we feel enamel is nicely intact and we don’t see caries in BWs
  • no sensitivity
33
Q

when do we use plastic fillings ? how do we do it ?

A
  • when we need to restore
  • remove caries
  • remove defective enamel (obvs not the dentine)
  • therefore we get shallow cavities and need to be particular when choosing restorative material
34
Q

why would we not use amalgam?

A
35
Q

when do we use GIC?

A
  • temp measure
36
Q

what is the best restorative material for MIH?

A

composite

37
Q

indications and contraindiactions for composite ?

A
38
Q

when do we use stainless steel crowns ?

A
  • good at addressing sensitivity
  • very extensive defects
39
Q

what are the disadvantages of stainless steel crowns ?

A

(gingival quality is poor due to poorly adapted margins of MIH)

40
Q

what are the different ways in which we can restore incisors ?

A
  • micro abrasion
  • bleaching
  • resin infiltration
  • COMPOSITE VENEERS (best)
  • porcelain veneers (contraindicated in children)
41
Q

pros and cons of microabrasion?

A
  • only used for subsurface defects but we know MIH is full thickness of enamel or in the inner layer of enamel
  • very easy to do
  • easy for pt and parents
  • very conservative
42
Q

what is con of bleaching ?

A
  • lightens whole tooth not just defects
43
Q

when do we use resin infiltrations ?

A

for white defects

44
Q

why is it better for child to grow and then get composite veneers?

A
  • when tooth erupts fully you will see the margin of the veneer showing through
45
Q
A