14. Hard tissue anomalies Flashcards
What is enamel hypoplasia? What do the teeth look like?
- quantitative defect- enamel is deficient in quantity
- forms irregular shaped teeth
- can be thin/pitted/smaller
- normal to see yellow dentine
What is hypomineralisation? What do the teeth look like?
- qualitative defect in the enamel
- opaque/creamy white or yellow/brown discolouration
How can you classify tooth discolouration?
- congenital/acquired
- extrinsic/intrinsic
- enamel/dentine
- generalised/localised
How can trauma cause defects?
- often will cause a localised defect
- trauma in primary teeth, especially under the age of 3 years old will affect the permanent tooth’s calcification
How does radiation cause defects?
- if a child has radiation, chemotherapy or lots of hospital visits for complex medical problems especially under the age of 3, may also affect enamel formation
How does infection cause defects?
- will often cause localised defect
- if a child has caries and chronic sinus in primary tooth, it may disrupt the formation of permanent incisor enamel
What can generalised defects be?
- often symmetrical and in multiple teeth
- chronological- chronological hypoplasia is a generalised form of hypoplasia, with a characteristic
presentation of symmetrical defects with a chronological pattern, with only parts of the teeth
developing (enamel secretion) at the time of the insult affected. - non-chronological- not related to any particular time during tooth formation
What are examples of chronological generalised defects?
- malnutrition/metabolic disturbances- eg, green teeth due to deposit of biliverdin
- intoxication- tetracycline- not licensed for under 12’s
- infection
What are examples of genetic non-chronological defects?
- tooth disturbance only or in association with disease or syndrome
- eg. amelogenesis imperfecta
What is an example of non-chronological, long lasting influence of environment or disease defect?
- chronic disease
- chronic intoxication
What are extrinsic factors causing tooth discolouration?
- beverages/food
- smoking
- poor oral hygiene
- drugs
- chromogenic bacteria
- chlorhexidine gluconate mouthwash
What are intrinsic factors causing tooth discolouration?
- enamel- localised/generalised
- dentine- local/systemic
What is chromogenic bacteria and what does it cause?
- bacteria is formed as a waste product, and this is stain forming
- makes the teeth appear black
What is the treatment for chromogenic bacteria?
- brush teeth with prophy paste
- if microflora of the mouth is still the same, it may redeposit onto teeth
- remove staining, give child week course of CHX which ma alter the microflora
- most children grow out of this bacteria, especially as permanent teeth erupt
What are localised causes for enamel discolouration?
- caries
- molar-incisor hypo-mineralisation
- injury/infection of primary successor
- internal resorption
- idiopathic
What are generalised causes for enamel discolouration?
- amelogenesis imperfecta
- drugs/chemicals
- idiopathic
- systemic illness (chronological)
What is the definition of molar-incisor hypomineralisation?
- hypomineralisation of systemic origin of one to four first permanent molars frequently associated with affected incisors
- prevalence= 3.6-25%
What has to be affected in MIH?
- at least one first permanent molar has to be affected for a diagnosis of MIH
- ## the more affected the molars, the more incisors involved and the more severe the defects
Where else may defects of MIH be seen?
- second primary molars
- premolars
- second permanent molars
- tip of the canines
What are clinical features of MIH?
- in the permanent dentition
- defect seen in first molars and incisors
- soft porous chalky enamel
- opacities well demarcated
- asymmetrical in defects
What is post eruptive breakdown?
- severely affected enamel breaks down following tooth eruption, due to masticatory forces
- you get loss of the initially formed surface and variable degree of porosity of the remaining hypomineralised areas
- the loss is often associated with a pre-existing demarcated opacity
- can cause areas of exposed dentine and subsequent caries development
- seen in severe
What are the signs and symptoms of mild MIH?
- demarcated enamel opacities without enamel breakdown
- induced sensitivity to triple air but not brushing
- mild aesthetic concern
What is severe MIH?
- breakdown and caries
- spontaneous hypersensitivity and impact on function
- strong aesthetic concerns that may have socio psychological impact
What is the association between primary teeth and MIH occuring?
Association between hypomineralisation of primary second molars and MIH suggests it can be used as a predictor for MIH.
What are aetiological factors of MIH?
- ameloblasts affected at a specific stage of development
- in early maturation or late secretory stage
- unknown factors
What 2 categories can MIH be split into?
- maternal
- neo-natal
What are maternal causes for MIH?
- endocrine disturbances
- infection
- drugs
- nutritional
- haematological
- metabolic
What are neonatal causes for MIH?
- prematurity
- systemic upset-fevers/chicken pox
- antibiotics
- dioxins in breast milk
- idiopathic
- genetic mutation
What are the treatment options for MIH?
- dietary advice, OHI
- relief of pain
- careful tx planning
- orthodontic assessment
What are the treatment options for MIH in posterior teeth that are moderately affected?
- fluoride varnish
- fissure sealants- better retention with bond
- SDF can help with hypersensitivity and caries progression
- stabilisation, eg. GIC
- restoration- can be challenging due to bonding and needing good moisture control
What is the management of MIH for severely affected teeth?
- refer
- PMC
- onlays
- extractions
What do you need to be careful about in enforced extractions?
If you take one molar out, the one in opposite arch may overerupt into space, stopping the 7’s from mesialising, causing occlusal problems. May need compensating extraction.
- consider if 7 is mesio angular
- check if the 5 is locked into the roots of the E which will stop the 5 from being distally impacted if the 6 is extracted
- if only one tooth is extracted, child can wear night time retainer to prevent over eruption
What age can you use GIC till to restore MIH teeth?
6-9 years
What is the best ages to extract a MIH molar?
6-10 years to allow spontaneous space closure
What are the tx options for MIH posterior teeth from least to most severe?
- sealants
- glass ionomer
- composite
- PMC
- extractions
What toothpaste can you use for MIH?
Accasion phsosphate toothpaste- not readily available in the UK and can help in reducing sensitivity
What are the treatment options for MIH in anterior teeth?
- regional whitening
- micro-abrasion
- resin infiltration
- macro-abrasion
- composite restoration
- vital bleaching- however cannot always do this if the teeth are really sensitive
What is amelogenesis imperfecta and what teeth does it affect?
- inherited disorder characterised by abnormal enamel formation
- usually affects both primary and permanent dentition
- several different types isolated
What other tooth factors is amelogensis imperfecta associated with?
- anterior open bite
- taurodontism
- delayed eruption
How can you classify amelogensis imperfecta by phenotype?
- hypoplastic
- hypomineralised
- mixed
How can you classify amelogenesis imperfecta by inheritance pattern?
- autosomal dominant
- autosomal recessive
- x-linked