MIH Flashcards
What is MIH?
hypomineralisation of systemic origin or one or more of the four permanent first molars as well as associated and affected incisors
What is the prevelance of MIH?
3.6-25% Weerhijme 2001§
How does MIH present?
affects one more more FPM and incisors demarcated patches white brown and cream post eruptive breakdown missing 6's heavily restored abnormal restorations calculus
WHat are the alternative terms to MIH?
cheese molars
hypomineralised 6’s
idiopathic hypomineralisation
non fluoride hypomineralisation
Differential diagnosis?
fluorosis
AI
Turner tooth
Idiopathic hypomineralisation
When does tooth formation begin?
6 weeks IU
What is the structure of enamel?
Unique
Organised tightly packed crystals
Highly mineralised 95% HAP
What are the phases of enamel production?
Sectretion
maturation
what is the first phase of amelogenesis?
Odontoblasts secrete collagen type 1
Then amelobalats differntiate in the internal enamel epithelium and they secrete enamel proteins which change shape and leads to mineralisation
What is the purpose of the secretoy phase?
defines the tooth form
deposition of organic matrix and amll thin crytsallites
there is an incremental growth in thickeness
t/f the secretory phase is a contrinuous process
F
What does a faiulre in the secreotry phase leasd to?
hypoplasia
this leads to small pits and grooves and gross enamel surface defects
What happens during the maturation phase of amelogenesis?
this is wehrre the quality of the tooth is established and the organic matrix is degraded and becomes minerlaised
What do ameloblasts do to calcium and phospate ions during maturation?
they move them
t/f the matrutration process is a contunous orocess post eription?
t
what happens to the ameloblasts following maturation?
apoptosis
What does failure in the maturation process lead to?
hypomineralisation
what is hypomineralisation?
this is when there is poor mineralisation of the enamel matrix and occurs later in development
What kind of enamel defect does hypomineralisation lead to?
this leads to white and brown opacities
t/f hypomineralised enamel is normal thickness?
T
but enamel is poor quality
What does hypomineralised enamel appear like down a microscope?
altered Ca/P balance withless distinct enamel rods and there is bacterial penetration into the enamel rods and it has a lower hardness than normal enamel
How does MIH occur?
not sure many factors timing of the insult pyrexia hypocalcaemia hypoxia of child or mother?
Lygidakis 2008
according to Crombie et al 2009 what is the aetology of MIH?
systematic review
exposiure to chemical: breasfeeding and fluride
peri natal and neonatal problems: malnutrituion, maternal health, birth problems
common child hood illness and mdeically compormised children: respiratory problms, otitis media, coeliac, renal, CF
T/F breastfeeding is protective against MIH?
T crombie et al 2009
What is the effect of early cessation of breast feeding and malnutrition on MIH?
this can lead to MIH
crombie 2009
WHat is the effect of fluoride on MIH?
there is weak evidence and leads to more diffude defects
Crombie 2009
What does it mean if there are visible defects in E’s? ref
Crombie et al 2009
co existing factoirs
How strong is the evidence for childhood illnesses and MIH link
Poor link
poor parental recall
confounding factors
What are the patient related challenging factors?
appearance:children and parents concenred about appearance, transition to secondary school
sensitivity: greater innneravtion of te subodontoblastic pulp horn regions, increased immune cell density, increased vascularuty in sensitive teeth, porous enamel causes dentine to become exposed, activation of A delta fibres. and increase C fibre action
Behaviour management: young pateints, repeated restrations, LA, fears
What are the restorative callanges?
incisors: site, colour, bonding, immature dentine, crumbly
molars: size, bonding, caries develpment, poor progmosis, immature dentine, difficult to anesthetise, crumbly, over eruption of molars
WHat are the solutions for the molars?
Phase 1: surveillance, recognise and review Phase 2: desens phase 3: temporarise, phase 4: restore, extract, orthodontic phase 5: maintenance
What does surveillance entail?
knowledge of prevalnce of the diease hypomin and plasia of primary teeth past medial history family histry review as teeth erupt
WHat does recognition and review entail?
consider differntial diagnosis
review according to caries risk status and abscence of problems
implement prevetativ regimen
WHat preventative techniques are there?
fluroide desensitising toothpaste CPP-ACP fissure sleants OH
How do you temporaise MIH teeth?
GIC, SSC
when would you restore or extract MIH teeth?
repemds on the extent of damage and consider the structure of the female and age of child, presence of adjacent teeth and consider oclusal and orthodontic factors
What can you rstore molars with?
composite
SSC
GOld or Cobalt Chrome onlays
WHat are the advanatges of using SSC?
good longevity
easy to fit
occlusion dimesnion settles
What are the advantages and dis of using fabricated onlays?
well tolerated
good longevity
permanents
BUT: time and lab bill
WHen would you xla MIH teeth?
poor prognosis
age dependant eg dependant on formatio of 7
are 7’s and 8’s present?
MUST CONSULT ORTHO
WHat are the options for incisors?
microabrasion etch bleach seal bleach composite bleach and comp
HOw does microabrasion work?
imprives surface discolouration which is limited to the outer surface only
100nm enamel is removed and can only be used for mild lesions
brown stains more easily removed than white
WHat do you use in microabrasion?
pumice and HCL
WHat do you use in etch bealch and seal?
60s etch and use 5% NAOCl bleach for 5-10mins and then re etch the tooth and apply clear fissure sleant
What type of bleaching agents should you use?
localised yellow brown patches: sodoum hypochlorite
darker lesions: peroxide
WHen are cast restoratons and comoposte done in MIH?
permanent teeth
cast used for seevre cases
