Molar Incisor Hypomineralisation Flashcards
What is the definition of MIH
- Developmentally-derived dental defect
- Involves hypo mineralisation of 1 to 4 permanent first molars
- Frequently associated with similarly affected permanent incisors
Difference between hypo plastic and hypo mineralised
Hypoplastic
- Ameloblasts fail to produce appropriate thickness of enamel
- Enamel crystals do not grow to the appropriate length
Hypomineralised
- Defect in initial crystallite mineralisation
- Crystallites fail to grow in thickness and width
What 3 things do you look for to make a diagnosis of MIH and description of each
Permanent first molars and incisors
- One to all four FPM shows hypo mineralisation of enamel
- If more molars and incisors are affected, the more severe
Demarcated opacities
- Clear demarcated opacities at the occlusal and buccal parts of the crown
- Vary in colour and size
- White, creamy or yellow to brownish
- Negligible or comprise the major part of the crown
Enamel disintegration
- Degree of porosity of hypo mineralised areas varies
- Severely affected enamel subjected to masticatory forces soon breaks down, leading to unprotected dentine and rapid caries development
- Post eruptive enamel breakdown
What colour do you expect opacities
-White, creamy or yellow to brownish
What is the official way of classifying MIH in terms of severity
Mild:
- Demarcated opacities are located at non-stress bearing areas
- No caries associated with the affected enamel
- No hypersensitivity
- Incisor involvement is usually mild if present
Moderate
- Demarcated opacities present on both molars and incisors
- Post-eruptive enamel breakdown limited to less than 2 surfaces WITHOUT cusp involvement
- Atypical restorations can be needed and normal
Severe:
- Post eruptive enamel breakdown
- Crown destruction
- Caries associated with affected enamel
- History of dental sensitivity and aesthetic concerns
Aetiology of MIH
Unknown
3 stages of amelogenesis and what goes down in eachh
1) Secretory. Issues here can cause hypo plastic enamel which is pathologically thin
2) Transition and 3) Maturation
Issues here can cause hypo mineralisation and hypo maturation where enamel is pathologically soft
Ameloblasts during early stages of maturation are highly sensitive to environmental disturbances
Mineralisation guide
-Learn on slide 15
When is the most critical period for enamel defects of FPM and incisors and why
-First 2.5 years of life as these coincide with early maturation
What are some of the reasons that enamel defects could occur and classify them
Prenatal factors
- Maternal pyrexia
- Medication
- Prolonged vomiting
- Maternal diabetes
- Maternal illness
Perinatal factors
- Caesarean section
- Prolonged/complicated delivery
- Hypoxia
- Prematurity/low birth weight
- Hypocalcaemia
Post-natal factors
- ENT infections
- Respiratory problems
- Pyrexia
- Prolonged meds
- Antibiotics
- Breastfeeding
- Chickenpox/mumps/measles
Prevalence of MIH
14.5% of UL population
What makes clinical management difficult
- May present with PEB of affected enamel
- Atypical location- shallow broad lesion
- Teeth may be sensitive
- Poor OH and caries
- Hypersensitivity and difficulty in obtaining adequate local analgesia
- Think IHS
-Restorations often fail
What does the colour of the lesion tell you about severity
- Yellow or brownish defect are of full thickness and more porous
- White or creamy white are less porous and variable in depth
6 Management stages for MIH
6 step management approach by William et al.
1) Risk identification
2) Early diagnosis
- Prevents PEB, reduces sensitivity and minimises care burden
3) Remineralisation and desensitisation
4) Prevention of dental caries and PEB
5) Restorations or extractions
6) Maintenance
According to Delivering better oral health 2014, what advice should be given 7yo with MIH
Enhanced prevention
-As with normal prevention AND
- Fluroide mouth rinse daily (0.05% NaF) at a different time to brushing (8+)
- Fissure seal permanent molars with resin sealant
- Apply fluoride varnish to teeth two or more times a year (2.2%)
- If 10+, prescribe 2800 ppm fluoride toothpaste
- If 16+, prescribe either 2800 or 5000ppm
- Investigate diet and assist to adopt good dietary practice in line with the eat well plate