Dental Anomalies IV Flashcards
Define MIH
Hypomineralisation of systemic origin of one to four first permanent molars, frequently associated with affected incisors
How does hypomineralisation and hypoplasia differ?
Hypomineralisation = Qualitative disturbance in enamel formation - enamel is there but malformed (post eruptive breakdown) Hypoplasia = Quantitative disturbance in enamel formation - enamel is missing
Clinical presentation of MIH?
Affected molars present with well demarcated white/yellow or brown/yellow enamel opacities
1-4 first permanent molars may be affected
In severe cases - defective enamel is lost soon after eruption to expose underlying dentine
Infected incisors also present with well demarcated white/yellow or brown/yellow opacities
Post eruptive enamel loss is not usually a feature
Increased risk of hypomineralised incisors where molars are more severely affected
Prevalence of MIH?
13%
Aetiology of MIH?
Pre-natal factors: 9% of MIH cases Maternal pyrexia Medication (antibiotics) Prolonged vomiting Maternal diabetes Vit D deficiency In vitro fertilisation
Peri-natal factors: 34% MIH cases Caesarean section Prolonged/complicated delivery Prematurity/low birth weight Twins
Post-natal factors (34% MIH cases): Ear/nose/throat infections Resp problems Pyrexia Seizures Urinary infections Antibiotics
Most causes associated with hypocalcaemia and hypoxia
Genetic susceptibility
Mechanism of MIH?
Insult to enamel formation from around 37 weeks to 3 yrs
Transitional and maturation phase of enamel affected
Reversible or irreversible damage to ameloblasts with qualitative disturbance to enamel formation
Protein retention and poor hydroxyapatite crystal formation
Low content of calcium and phosphate ions
Features of enamel, dentine and pulp in MIH?
Enamel
- Porous
- Week
- Poor etch pattern
Dentine
- Sparse reparative dentine and irregular globular dentine
- Influx of bacteria in dentine tubules
Pulp
- Underlying chronic pulpal inflammation
- Increased immune cells, vascularity and neural density
Pt related clinical challenges with MIH?
Extreme tooth sensitivity
Aesthetic concerns
Anxious about dental tx
Need for long term interventions (financial burden)
Clinical related challenges with MIH?
Difficulty in achieving adequate level of analgesia for restorative treatment
High failure rate of adhesive restorations and sealants (poor shear bond strength)
Tooth tissue loss
High caries experience
Holistic care for children for MIH?
Prevention, remineralisation, alleviation of symptoms
- Sensodyne
- F varnish
- Tooth mousse (for remineralisation of enamel - pt application daily in trays or locally to affected tooth)
- F.S but have high failure rates in hypomineralised enamel (if use warm water and cotton pledgets to remove etch and avoid aspirators, use of light cured glass ionomer sealants)
Tx planning for first permanent molars
Improvement of incisor aesthetics
Incorporating a child centred approach
Review/prevention
- Topical F application
- Tooth mousse
- FS
Restore
- Adhesive restorations
- PMC
- Lab formed crowns
Extract BUT at correct time so 5 does not drift distally and 7 will fill space mesially (9 and a half - 10 yrs old)
- LA/IS/GA
- Need for compensating extractions
- Ortho considerations
When to seek ortho opinion when extracting the first permanent molars?
Class II cases and III cases
Hypodontia cases
Severe crowding cases
How to restore chrildren’s teeth with MIH?
Resin modified glass ionomer
Composite resin
PMC
Cast onlays
Adhesive restorations
- GIC for short term restoration prior to definitive restoration or extraction
- Composite resins only indicated for mildly affected teeth with no cuspal involvement margins of restoration should extend beyond visibly affected enamel
Advantages of PMC?
Prevent further tooth deterioration/caries
Controls tooth sensitivity
Establish correct interproximal contacts and occlusal relationships
Not as technique sensitive or costly as cast restorations
Quick
Disadvantages of PMC?
Adverse reactions in patients with a nickel allergy
Production of anterior open bite if not fitted correctly
Gingival inflammation
Not a permanent restoration
Cast restorations for MIH FPM?
Indirect gold onlays for moderate or severe hypomineralisation where the maintenance of FPMs is indicated in the long term
Placement usually considered in late mixed or early permanent dentition
