Molar Incisor Hypo-mineralisation Flashcards
What is the definition of MIH?
Hypo-mineralisation of systemic origin of between 1 and 4 permanent molars, frequently associated with affected incisors
Marks in MIH are quite distinctive from anything else. Describe what they are like? (4 points)
- Well demarcated (actual blobs as opposed to being diffuse through all of the enamel)
- Frequently have chalky white parts and sometimes also yellow parts (or can be more brown)
- Don’t tend to be very symmetrical
- Find between none and all 8 of the incisors
What is the prevalence of MIH in the general population?
- Between 10-20%
What is the definition of hypomineralised?
- Disturbance of enamel formation resulting in a reduced mineral content
How are teeth developed to be hypomineralised?
- Happens in the later stage of amelogenesis
- Secretory phase is okay but mineralisation phase has something wrong with it
- When tooth erupts it is the right shape but has parts of the enamel which aren’t as strong as they should be as they are not formed properly
What is the definition of hypoplastic?
- Reduced bulk or thickness of enamel.
May be:
- True - enamel never formed
- Acquired - post-eruptive loss of enamel bulk
How are teeth developed to be hypoplastic?
- Tooth erupts and is going to look amorphous - not the right shape
- When lay down jelly in the secretory phase the template hasn’t developed properly
- Wave of mineralisation has occurred as normal
What causes post-erupted hypoplasia?
Because hypomineralised teeth erupt looking normal but have soft enamel, what can happen is bits start to fall off them and they look at the tooth and think it is hyperplastic
- Not strictly true - this is why we would call it post eruptive hypoplasia
Why is it so difficult to determine the aetiology of MIH? (4 points)
- Unclear diagnostic criteria in classification
- Most parents can’t remember details form 8-10 years before
- Variations in quality and completeness of case records
- Study population small
It is though that MIH is a developmental condition. When is it though this occurs?
- Some kind of disturbance during the first year of life
What are the 3 different periods of time you would enquire about clinically?
- Pre-natal
- Natal
- Post-natal
In terms of pre-natal, what would you ask the mothers about?
- How their pregnancy was (specifically during the third trimester)
- Usually nothing identified but possible causes could be pre-eclampsia or gestational diabetes in the mother
In terms of peri-natal what would you ask the parent?
- Ask if baby was full term or premature (premature more likely to have it)
What are possible pre-natal causes of MIH? (4 points)
- Anoxia (not having enough O2 at time of birth)
- Trauma (was there need for C section, Forceps delivery)
- Hypocalcaemia (not getting enough calcium)
- Pre-term birth
In terms of ‘post natal’ what would you ask the parent? (3 points)
- If the child has had fever and medication
- Socioeconomic status
- Rural Vs Urban
What is the incubation period of measles?
- 10-14 days
What are common signs and symptoms of measles? (6 points)
- Fever
- Rash
- Koplik’s spots
- Conjunctivitis
- Coryza
- Cough
What is Koplik’s spots?
- White spots inside the mucosa
What is Coryza?
- Runny nose
What is otitis media?
- Middle ear infection
What are examples of secondary infections of measles ? (6 points)
- Otitis media
- Bronchopneumonia
- Corneal ulcers
- Stomatitis
- Gastroenteritis
- Appendicitis
What is the duration of illness of measles?
- 7-10 days
What are common signs of rubella? (5 points)
- Mild fever
- Maculopapular rash
- Generalised lymphadenopathy
- Malaise
- URTI
What is the duration of illness of Rubella?
- 8-10 days
What are common secondary infections of rubella? (3 points)
- Encephalitis
- Arthritis
- Purpura
What is encephalitis?
An inflammation of the brain usually caused due to infection
What are common signs of chicken pox? (3 points)
- Low grade fever
- Rash
- Crops of spots progressing from macule-papule-vesicle
What is the duration of illness of chicken pox?
- 6-10 days
What are common secondary infections of chicken pox? (3 points)
- Secondary infections of lesion
- Encephalitis
- Pneumonia
Which type of tooth has more neural density: normal or MIH?
MIH
Which type of tooth has more immune cell accumulation: normal or MIH?
MIH
Which type of tooth has increased vascularity: normal or MIH?
MIH
What is dentine hypersensitivity?
- Porous enamel or exposed dentine facilitates fluid flow within dentine tubules to activate A-delta nerve fibres
What is peripheral sensitivity?
- Underlying pulpal inflammation leads to sensitisation of C-fibres
What is Central sensitisation?
- Pain process coming from brain due to continued assault on the teeth
- Don’t know what pain mechanisms are but know they are more sensitive
What are possible clinical problems of MIH? (3 points)
- Loss of tooth substance (breakdown of enamel, tooth wear, secondary caries)
- Sensitivity
- Appearance
What are possible treatment options of MIH? (4 points)
- Composite/GIC restorations
- Stainless steel crowns
- Adhesively retained copings
- Extraction (8.5-9.5 years)
What do you want to see on a radiograph to know the ideal time to remove permanent first molars with MIH?
- Calcification of the bifurcation of the lower 7’s
- Once have this then want to get out at least the lower 6’s
- If do it at this point what will happen is you take the 6’s out and before the 7’s erupt it will start to drift forwards and when early teens - end up having 2 premolars and a 7 but have gaps between them, self cleansing so removes caries risk
- In most cases would take out upper 6’s at the same time BUT must be removed at some point as otherwise the will over erupt
- Other things like to see is developing third molars
When extracting HFPM’s what do you need to consider? (4 points)
- Age
- Skeletal pattern
- Future orthodontic needs
- Quality of teeth e.g. caries
What are possible treatments of affected incisors? (5 points)
- Acid pumice microabrasion
- External bleaching
- Localised composite placement
- Full composite veneers
- Full porcelain veneers
