Molar-incisor hypomineralisation (MIH) Flashcards
MIH definition
hypomineralisation of a systemic origin - presenting itself as demarcated, qualitative defects of enamel of 1-4 first permanent molars, frequently associated with affected incisors also
Must be present on molar teeth
No change in enamel thickness only mineralisation and enamel hardness
not fluoride related
MIH visual presentation
Spectrum
White, cream yellow or brown opacities (not translucent like normal enamel)
May be diffuse or well demarcated
Post eruptive breakdown - due to low mineralisation
If more molars are affected - higher chance of incisor involvement
Mild speckling
Other clinical features of MIH
Atypical restorations
Caries on cusp tips
Asymmetric distribution
Canine tip involvement
Primary teeth are unaffected
may affect 2nd molars
risk of hypodontia - lower 5s
Ectopic 1st perm molars - more mesial (early loss of upper second primary molars)
Primary molar infraocclusion
macrodont and microdont teeth
DHS
How to distinguish MIH from caries?
MIH lesions may be present occlusally, buccally or palatally - not just in areas of stagnations such as fissure pattern and mesial/distal
Fissure caries - small break in enamel with white deminerlisation around it - spread is more in dentine
Cuspal breakdown occurs in severe cases and teeth can appear shallow looking
atypical restorations (shallow) are seen - cuspal breakdown around restoration
caries will be seen spreading into dentine (cone shaped lesions RG) - areas of stagnation –> fissures and interproximally
can get caries on MIH
Aetiology of MIH
Cause is unclear
Localised and asymmetrical legions = systemic
disruption in amelogenesis process during the early maturation stage or late secretory stage (tooth doesn’t reach required mineralisation only correct thickness)
systemic factors during last gestational trimester and 1st 3 years of life (Pre, peri and post natal)
more teeth seem to be affected/more marked lesions if the disturbance occurred prenatally
Possible causes of MIH to deduce from medical history
SYSTEMIC INSULTS
Previous history of
-Upper resp tract infections
-Use of antibiotics
-Perinatal complications (jaundice, feeding issues)
-Dioxins (pollutant)
-Low birth weight
-Oxygen Starvation
-Calcium and Phosphate metabolic disorders
-Frequent childhood diseases - 1st 3 years of life
-Genetic (do parents or siblings have it)
Clinical problems associated with MIH
Post eruptive enamel breakdown - pulp involvement
Prone to caries on top - pulp involvement
Tooth sensitivity - poor OH. Teeth have similar nerve state to those with caries induced chronic pulp inflammation
- not a PC as not known any different (Ask if avoid hot or cold)
May make anaesthesia difficult -consider articaine buccal infiltration
Behavioural management issues
Aesthetics (anterior teeth) - dont rush into restorative cycle - teeth tend to mature and improve
Tooth loss - extractions :( in hypodontia cases
Multiple appts - time of school, parents, financial pressure to attend appts, transport, cooperation etc
Treatment of MIH with products
Enhanced prevention of caries (high risk)/desensitisation/remineralisation:
fluoride
CPP ACP tooth mousse - makes teeth less sensitive and prevents wear of outer enamel. Apply with clean finger or cotton bud after brushing
Treating anterior teeth for MIH
Bleaching - to even out whiteness, not allowed below age of 18
Microabrasion- 3 cycles of phosphoric etch applied to brown lesions under rubber dam. Removes 100 micron of tooth tissue. May be followed by comp veneer - CARE with sensitivity
Etch bleach, seal- Etch tooth, bleach with NaOCl, seal with clear resin
Infiltration with ICON resin - works well on well demarcated white lesions
Composite restorations / veneers
*CONSIDERATION: you can remove brown discolourations with handpiece instead of etch BUT if intense then lots of removal required and also bulk fill of composite after - neither ideal
Porcelain veneers (when older and gingival margins are fully developed?)
Treatment of posterior teeth with MIH
Restorations, crowns, onlays:
Temporary stabilisation:
- GIC (uncooperative sensitive lesion, stabilise tooth before extraction?) , GIC may bond better to hypomineralised enamel than composite.
–Preformed metal crowns (hall technique - minimal prep)- full coverage, stabilises and reduces sensitivity to preserve tooth for longer for def restorations later. If the molar has not fully erupted, trim the crown down
Definitive tx:
Composite (occlusal surfaces is ideal, minimal lesions, remove brown hypomineralised tissue for good bonding)
Indirect onlays - metal, gold, tooth-coloured, require cooperation (older), shallow defects as only 3/4 crown and prep on unaffected enamel
CONSIDER when past point of extractions and only one or two teeth affected
Tx plan for an MIH patient
Emergency -
Skip unless patient is in pain or sensitivity –> temporary restoration
Stabilisation-
Temporary restorations on molars - GIC will be able to better cover areas of exposed dentine
SSC - immediate first step too until definitive restoration
Fluoride varnish
Desensitising toothpaste/tooth mousse - CPP ACP
Prevention-
Plaque scores, PMPR, interdental cleaning
Fluoride:
-Duraphat toothpaste - 2800 ppm
-Topical FV
-Daily fluoride rinse
Diet chart
Fissure seal PE molars/premolars - GIC if resin does not work
Restorative-
Anterior:
-Microabrasion followed by ICON infiltration concept (clean, etch, dry and then icon resin infiltrate (dry)) (no LA required, just rubber dam and light cure)
-composite veneers (buildup) - use handpiece to remove discolouration and create space for composite - composite masking not 100% if opacity intense –> either have to remove lots of tooth tissue or bulk fill composite - neither ideal
Posterior:
-planned XLAs of 6s poor prognosis and wait for orthodontics timing (OPG to see development - 7s to replace them)- temporise with GIC/PMC to buy time
(if 12 years or above, 7s may be past bifurcation but still XLA and fixed appliance option viable)
Crown/ metal onlay/ restoration
Maintenance-
MIH patients are high risk, see every 3 months with 6 monthly bws. Fluoride varnish 4 times a year.
OHI
Plaque scores
Check FS and restorations and SSCs
PMPR
Bitewings - 6 mos
What to consider when extracting 6s?
May be necessary if prognosis is poor
Consider the prognosis of the remaining 6s
Which teeth are present and what is the developmental status of the rest of the dentition?
Is there malocclusion present?
Lower molars have less predictable space closure than uppers
Compensating > balancing as more evidence
Timing the extraction of lower 6s
Why? - less predictable space closure than uppers - so cant do late extractions
To be timed between ages of 8-10
Upper 2’s erupted/5s not yet erupted
Consider whether the bifurcation of the 7s has formed and whether there is bone overlying the occlusal surface
Position of the 5s - in the bifurcation of E’s
Have the 8s started to develop? May not start to develop until the age of 14. Big factor in whether there will be spontaneous space closure.
What to do about the 6 in a patient with class 1 molar relationship who is unlikely to need orthodontics with extractions
Poor prognosis 6, TPM present
If 6 is of poor prognosis -
Extract between the age of 8-10 before the 7 erupts
Compensate for lower 6 extraction to prevent over-eruption of the upper tooth
What to do about the 6 in a patient that may need possible orthodontic tx with extractions (class II or class III) (poor prognosis, TPM present)
If 6 poor prognosis and TPM present, malocclusion:
-Interceptive extraction over restoration
-Extract 6’s and any other teeth needing removal at time specified by orthodontist (consult)
NOTE:
-Maintain until 7s erupted
As ortho tx w/ extractions is creating space to relieve crowding and align SO e.g.
*class II - aim is to reduce overjet so extraction of 6s not ideal
*class III - dont want to extract at all, espesh lower molars
6s arent good extraction teeth for creating space in ortho
