Dental anomalies Flashcards
what is an anomaly? what causes anomalies?
- something that is out of the ordinary or norm
- can be extreme variations or slight deviations
- caused by one or many contributors
- abnormalities result from intrinsic or extrinsic factors
what are some examples of intrinsic factors?
- hereditary
- metabolic dysfunction
- mutations
what are some examples of extrinsic factors?
- physical or chemical trauma
- biological agents
- nutritional deficiencies
- stress
- habits
- environmental conditions
what is hereditary?
- means that the condition is because of a genetic factor or factors
what is congenital?
- means that the condition occurs at or before birth
what is a family tendency?
- when a condition exhibits some evidence of an inherited tendency but is inconclusive
what is a developmental anomaly?
- when a condition results during formation and development
classification of anomalies in dentistry
anomalies resulting in a variation in the size of teeth are:
- macrodontia: teeth are too large
- microdontia: teeth are too small
anomalies resulting in the variation of the number of teeth are:
- hyperdontia: multiple extra teeth (supernumary)
- anodontia: too few teeth
what is total anodontia?
- when all the teeth are missing
what is partial anodontia?
- when a less than normal number of teeth are present
what is true anodontia?
- the congenital absence of teeth that can occur in both the primary and permanent dentition. when no primary tooth is present than a permanent one will not develop (starts with primary)
which teeth are most likely to be missing?
1 - most likely is the missing of the 3rd molars, mx more often than mn
2 - next are permanent mx lateral incisors (1-2% of population)
3 - third most missing tooth is the permanent mn 2nd premolar (1%)
which tooth is the least likely to be missing?
- the canine
what is hyperdontia?
- too many teeth, more common anomaly
- 0.1-3.6% of people have too many teeth
- they are referred to as supernumerary teeth
what are supernumerary teeth?
- extra teeth that form in the jaw
what are mesiodens?
- supernumerary teeth that develop in the midline of the mx central incisors
what are distomolars?
- fourth molars located posterior to the 3rd molars
- termed 9s in the FDI notation
- mx distomolars are next most common supernumerary after mesiodens
what is a paramolar?
- a supernumerary tooth that is situated buccally or lingually to a molar is called a paramolar, they are usually small and rudimentary
where is a common place for supernumerary teeth to form on the mandible?
the premolar area, only 10% of all supernumeraries occur on the mandible though
what is a supplemental supernumerary tooth?
when a supernumerary tooth is normal in size and appearance
when is a supernumerary tooth termed conical?
if it is odd shape or cone-like in appearance
when is supernumerary tooth termed a tubercle?
if it is very small
what is odontoma?
a tumorous anomaly of dental tissue. they are:
- complex
- compound
what is a complex odontoma?
a single blob-like mass of dentin, enamel and cementum
what is a compound odontoma?
several masses that resemble rudimentary teeth but are very small
what is dens in dente? when does this occur? where is it most common?
- a tooth within a tooth
- occurs during development: the outer surface of the crown turns itself inward before mineralization (enamel is growing within the tooth)
- most common on permanent mx lateral incisors
what is dilaceration?
- a tooth that has a very sharp bend in the crown or root
- can make extractions very difficult
what are dwarfed roots?
- a condition where the roots are extremely short in comparison to their crowns
what is gemination? what can it result in?
- occurs when the tooth attempts to divide itself or partially twin itself by splitting it tooth germ
- gemination could result in twin teeth, in most cases, geminated teeth are only partially split
- usually have a single root and share a common pulp canal
what is a bifurcated crown?
- a tooth that is split into two crowns and one root
- commonly found in anterior area and the primary dentition
what is fusion?
- occurs when two separate tooth germs unite
- the two teeth may unite along part or the entire length of the root, at the dentin
- for 2 teeth to be joined there has to be one less tooth than the normal complement of teeth
what is concresence?
- type of fusion that occurs after the roots have formed
- thought to occur sometime post trauma
- involves 2 adjacent roots contacting each other and fusing by deposition of cementum
- can occur before or after eruption
what is hypercementosis?
- deposition of an excess of secondary cementum (usually at the apex) but can occur along the entire apical root 1/3
- cementoma is a form of hypercementosis that is affiliated with localized destruction of bone
what are enamel pearls?
- small masses of enamel on the root surface apical to the CEJ. they are often found in bifurcated or trifurcated area of multirooted teeth
what is enamel dysplasia?
abnormalities of tooth structure. includes 2 different types of abnormal enamel development:
- enamel hypoplasia
- enamel hypocalcification
what is enamel hypoplasia? what is the result of this?
- any condition that inhibits enamel formation
- a disturbance of or damage to ameloblasts during enamel matrix formation.
- results in an alteration of tooth form and colour. may leave small pits or grooves at different levels of the crown
what is enamel hypocalcification? what can cause it?
local disturbance in the enamel formation, can be caused by:
- inflammation/local infection
- fever
- systemic disease (deficiencies in vitamin A, C, D, Calcium or Phosphorous)
- measles, chicken pox, scarlet fever (due to increased body temp)
- heredity
what are hutchinson’s incisors? what causes this?
- notched incisors sometimes described as screwdriver shaped
- form as a result of prenatal syphilis
- mulberry molars: irregular shaped molars with poorly formed cusps
- both are characteristics of congenital syphilis
what is enamel fluorosis?
- enamel hypoplasia resulting from fluoride ingestion
- caused by excessive systemic fluoride in the tooth structure during development
what can cause fluorosis?
- naturally with well water that contains excessive amounts of fluoride
- accidentally by a child taking too much fluoride via fluoride supplements, mouthwashes and toothpastes
how does fluorosis appear? what do we call this appearance?
as mild white flecks to larger opaque areas to even brown rough freckle-like areas on the crown
- termed mottled enamel
what is amelogenesis imperfecta? how does the enamel appear?
- another developmental anomaly related to enamel hypoplasia
- this is a hereditary factor rather than acquired
- usually affects both primary and permanent dentitions, though sometimes can affect only permanent
- enamel, when present, is: thin, stained various shades of yellow and brown, chips easily
- pt may claim to have soft teeth
what is turners tooth?
- hypoplasia of a single tooth
- usually occurs on permanent mx anterior tooth due to: localized infection of a primary tooth or trauma to a developing tooth. either way, the ameloblastic layer is disturbed.
what is enamel hypocalcification?
- often appears as a localized white spot on the middle third of smooth crowns
- the underlying enamel may be soft and susceptible to caries
what is dentinogenesis imperfecta?
- a hereditary dentin developmental anomaly
- dentin is coloured grey, brown or yellow
- key feature to this anomaly is: that the pulp chambers and root canals are completely filled in with dentin. this occurs because the odontoblasts continue to produce dentin until the pulp chambers and canals are filled
- enamel tends to chip away because the poorly developed dentin underneath is not supportive
- may loose teeth prematurely
what is tetracycline staining?
- this condition occurs when an expectant mother or a young child with developing teeth takes the antibiotic tetracycline
- the teeth range from yellowish to brownish or greyish to blue
common teeth to have abnormal crown shapes:
- mx 3rd molars followed by mn 3rd molars
- permanent mx lateral incisors can be pegged - more than 1% of the population
- mn 2nd premolars - 3 cusp form
- accessory cusps or tubercles on any teeth can occur
common teeth to have abnormal root formation:
- mx 2nd premolars can be bifurcated
- mx 1st premolar 40% have single root
- mn premolars and canines can have accessory roots, usually at the apex
- root or crown dilaceration (more than a 40 degree bend) in 3rd mn molars
- mx teeth with dwarfed roots are not uncommon. can also happen with mn incisors
- hypercementosis can occur on any tooth and appears first as a radiolucent area then turns opaque as it is more mineralized - is not pathologic
