Molar-Incisor Hypomineralisation Flashcards
how is enamel formed?
- ameloblasts
- retreat from the ADJ
- secrete matrix protein
- initial calcification (mineralisation)
- ameloblasts transition
- secrete enzymes - remove organic component
- full mineralisation to 99% = maturation stage
what is hypoplastic and hypo maturation? at what stages of enamel formation do these occur?
both are incomplete developments of enamel
hypoplastic
- during the enamel matrix laying down
- reduced thickness of enamel
hypomaturation
- in the calcification or maturation stage
- enamel is much softer
reduced calcification of enamel
how are enamel defects basically classified?
systemic
- environmental - chronological (MIH) or generalised (fluorosis)
- genetic - amelogenesis imperfecta - generalised defect
local
- trauma infection
how do you describe enamel defects - 3 main terms - give examples
- demarcated - MIH
- clear boundary between defect
- yellow, white or brown - diffuse - fluorosis
- no clear boundaries
- lines/patchiness - hypoplastic
- loss of enamel
- pits or grooves
define MIH
hypomineralisation of systemic origin
- of 1+ permanent molars as well as any associated and affected incisors
5 key features of MIH
demarcated defects of 1st molar
- may be associated with demarcated incisor teeth
- second primary molars MAY also be hypomineralised
- post-eruptive breakdown
- sensitivities
- more susceptible to caries - decay faster
- more difficult to restore
the darker the lesion, the more….
porous
= enamel is more affected
possible aetiologies of MIH
environmental changes
chronic illness
low birth weight
chicken pox
antibiotics
dioxine exposure - pollutants
how is MIH treated/managed?
- start with the molars - prognosis
- assess the devlopmental defects
- porosity, caries risk
- post-eruptive breakdown
- pain/sensitivities
- does it extend across the cusps - harder to restore - options: extract or conserve
- monitor
what is the ideal orthodontic patient
class I occlusion
normal overbite
mild-mod crowding
all permanent teeth are present
when is it best to extract a first molar? a 6? what are the issues
lower arch
- pt to be 8-9
- L7’s have calcified dentine
- 7 can move into the space
upper arch
- timing is less important
- likely to get a space closure if extracted before 11/12
issues
- if you extract a lower 6
- upper 6 may overerupt
= you need to compensate and XLA opposite tooth
- don’t need to compensate with an U6
how is a MIH tooth conserved?
give the options, describe each with pros and cons
tooth mousse
- Recaldent - casein phosphopeptide
- changes ionic balance
- pushes Ca into the tooth
- may have milk proteins - ALLERGIES
- how to use: at home or dentist
fissure sealants
- enamel needs to be intact and hard
- no sensitivities
- if bitewings have no caries
amalgam
- little value
- not adhesive, marginal leakage, poor retentive in large, shallow cavity
GIC
- good for a temp
- adhesive, fluoride release, good insulator, poor wear resistance
composite
- good
- good wear resistance, supports tissue, technique sensitive and time consuming
SSC - stainless steel crown
- requires approximal and occlusal prep
- prone to wear, poor aesthetic, poorly adapted margins
onlay
if the incisors are also affected, how are these managed aesthetically?
- bleaching
- will lighten all the tooth - composite veneers
- porcelain veneers - CI for children
- resin infiltration
- micro abrasion
- usually on subsurface defects
