Dental anomalies

Question 1

what is an anomaly? what causes anomalies?

Answer 1

• 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

Question 2

what are some examples of intrinsic factors?

Answer 2

• hereditary
• metabolic dysfunction
• mutations

Question 3

what are some examples of extrinsic factors?

Answer 3

• physical or chemical trauma
• biological agents
• nutritional deficiencies
• stress
• habits
• environmental conditions

Question 4

what is hereditary?

Answer 4

• means that the condition is because of a genetic factor or factors

Question 5

what is congenital?

Answer 5

• means that the condition occurs at or before birth

Question 6

what is a family tendency?

Answer 6

• when a condition exhibits some evidence of an inherited tendency but is inconclusive

Question 7

what is a developmental anomaly?

Answer 7

• when a condition results during formation and development

Question 8

classification of anomalies in dentistry

Answer 8

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

Question 9

what is total anodontia?

Answer 9

• when all the teeth are missing

Question 10

what is partial anodontia?

Answer 10

• when a less than normal number of teeth are present

Question 11

what is true anodontia?

Answer 11

• 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)

Question 12

which teeth are most likely to be missing?

Answer 12

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%)

Question 13

which tooth is the least likely to be missing?

Answer 13

• the canine

Question 14

what is hyperdontia?

Answer 14

• too many teeth, more common anomaly
• 0.1-3.6% of people have too many teeth
• they are referred to as supernumerary teeth

Question 15

what are supernumerary teeth?

Answer 15

• extra teeth that form in the jaw

Question 16

what are mesiodens?

Answer 16

• supernumerary teeth that develop in the midline of the mx central incisors

Question 17

what are distomolars?

Answer 17

• fourth molars located posterior to the 3rd molars
• termed 9s in the FDI notation
• mx distomolars are next most common supernumerary after mesiodens

Question 18

what is a paramolar?

Answer 18

• a supernumerary tooth that is situated buccally or lingually to a molar is called a paramolar, they are usually small and rudimentary

Question 19

where is a common place for supernumerary teeth to form on the mandible?

Answer 19

the premolar area, only 10% of all supernumeraries occur on the mandible though

Question 20

what is a supplemental supernumerary tooth?

Answer 20

when a supernumerary tooth is normal in size and appearance

Question 21

when is a supernumerary tooth termed conical?

Answer 21

if it is odd shape or cone-like in appearance

Question 22

when is supernumerary tooth termed a tubercle?

Answer 22

if it is very small

Question 23

what is odontoma?

Answer 23

a tumorous anomaly of dental tissue. they are:

• complex
• compound

Question 24

what is a complex odontoma?

Answer 24

a single blob-like mass of dentin, enamel and cementum

Question 25

what is a compound odontoma?

Answer 25

several masses that resemble rudimentary teeth but are very small

Question 26

what is dens in dente? when does this occur? where is it most common?

Answer 26

- 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

Question 27

what is dilaceration?

Answer 27

- a tooth that has a very sharp bend in the crown or root | - can make extractions very difficult

Question 28

what are dwarfed roots?

Answer 28

- a condition where the roots are extremely short in comparison to their crowns

Question 29

what is gemination? what can it result in?

Answer 29

- 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

Question 30

what is a bifurcated crown?

Answer 30

- a tooth that is split into two crowns and one root | - commonly found in anterior area and the primary dentition

Question 31

what is fusion?

Answer 31

- 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

Question 32

what is concresence?

Answer 32

- 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

Question 33

what is hypercementosis?

Answer 33

- 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

Question 34

what are enamel pearls?

Answer 34

- small masses of enamel on the root surface apical to the CEJ. they are often found in bifurcated or trifurcated area of multirooted teeth

Question 35

what is enamel dysplasia?

Answer 35

abnormalities of tooth structure. includes 2 different types of abnormal enamel development: - enamel hypoplasia - enamel hypocalcification

Question 36

what is enamel hypoplasia? what is the result of this?

Answer 36

- 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

Question 37

what is enamel hypocalcification? what can cause it?

Answer 37

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

Question 38

what are hutchinson's incisors? what causes this?

Answer 38

- 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

Question 39

what is enamel fluorosis?

Answer 39

- enamel hypoplasia resulting from fluoride ingestion | - caused by excessive systemic fluoride in the tooth structure during development

Question 40

what can cause fluorosis?

Answer 40

- naturally with well water that contains excessive amounts of fluoride - accidentally by a child taking too much fluoride via fluoride supplements, mouthwashes and toothpastes

Question 41

how does fluorosis appear? what do we call this appearance?

Answer 41

as mild white flecks to larger opaque areas to even brown rough freckle-like areas on the crown - termed mottled enamel

Question 42

what is amelogenesis imperfecta? how does the enamel appear?

Answer 42

- 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

Question 43

what is turners tooth?

Answer 43

- 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.

Question 44

what is enamel hypocalcification?

Answer 44

- often appears as a localized white spot on the middle third of smooth crowns - the underlying enamel may be soft and susceptible to caries

Question 45

what is dentinogenesis imperfecta?

Answer 45

- 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

Question 46

what is tetracycline staining?

Answer 46

- 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

Question 47

common teeth to have abnormal crown shapes:

Answer 47

- 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

Question 48

common teeth to have abnormal root formation:

Answer 48

- 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