DISORDERS OF TOOTH FORMATION Flashcards
what 3 things can determine the shape/size of teeth
- genetically determined
- local or systemic factors
- BOTH
what is hypodontia
failure of development/missing teeth - 8’s most common, then 5’s and upper 2’s
what is anodontia
this is the total lack of teeth (genetic disorder - no teeth present)
what are the treatment options for people with hypodontia/missing teeth
- full and partial dentures
- implants
missing teeth and small teeth are often present together, composite is advised to mask conical of mis-shaped teeth
what is hyperdontia (supernumary)
this is when a patient has extra teeth
- patients with supernumerary primary teeth have 30-50% chance of being followed by supernumerary permanent teeth
where are extra teeth (hyperdontic) in patients mouths usually found typically?
- ANTERIOR MAXILLA in the MIDLINE or immediately adjacent to midline referred to as MESIODENS
- MOLAR regions are referred to as PARAMOLARS or DISTOMOLARS
- 5:1 maxilla:mandible ratio!!!
- usually idiopathic but may be associated with syndromes such as cleidocranial dysplasia
what is a mesiodens
Mesiodens is a supernumerary tooth present in the midline between the two central incisors
what is megadontia (3)
- this is when the teeth are larger than normal
- very rare
- seen in cases of PITUITARY GIGANTISM where teeth are bigger than normal
what is microdontia(7)
- this is when teeth are smaller than normal
- MAXILLARY LATERAL INCISORS and MAXILLARY THIRD MOLARS mostly affected
- maxillary lateral incisors - peg/conical shaped crowns
- maxillary third molar - small but normal shape
- identified radiographically (smaller in proportion to other teeth)
- more common in FEMALES
- OFTEN ASSOCIATED WITH VARIOUS TYPES OF ECTODERMAL DYSPLASIA AND DOWN SYNDROME!
what are the things we can consider in terms of root size within the dentition (4)
- racial variation - SHORTER ROOTS seen in people of oriental/chinese background
- african origin - LARGER ROOTS SEEN in these type of peopel
- irradiation of the jaws, or chemotherapy, during root formation may lead to SMALLER roots
- POSS CONSIDER ORTHO REFERRAL/TREATMENT
what is gemination (doubling)?(4)
‘DOUBLE TEETH’
- there will have been attempts at developmental separation of a SINGLE tooth germ to produce two SEPERATE teeth
- the cause is unknown
- anteriors/deciduous teeth are most commonly affected
- 1 canal and incisal notching present in these teeth
what is a concrescence
- this is the joining of two teeth, one of which may be a supernumary, by cementum (root surface)
- cause is thought to be from trauma or crowding as root surfaces may be in close proximity
- MAXILLARY MOLARS most commonly affected
what is dilaceration(6)
- this is the GROSS disruption of root formation
- cause is thought to be trauma to TOOTH GERM during root development
- WHEN THE REMAINDER OF THE TOOTH IS FORMED AT AN ANGLE
- this may appear anywhere along the root surface
- discovered radiographically
- this can impede tooth eruption
what are the treatment options for tooth formation disorders
PRIMARY DENTITION - NO TREATMENT
PERMANENT DENTITION - dependant on:
- space available within arch
- morphology of pulp chambers and or root canals
- degree of attachment between the two parts of the tooth or teeth.
what do we mean by an invaginated tooth (5)
- this is the infolding on the palatal surface of the crown of the tooth and lined with enamel, sometimes extending into the root
- appear as a normally shaped/malformed crown that exhibits a deep pit or crevice in area of cingululm
- radiographically - a tooth like structure appears within the involved tooth
- pear shaped mass of enamel is seen in dentine surrounding a radiolucent area
- hence, ‘dens in dente’ - TOOTH WITHIN A TOOTH
