Disorders of Tooth Formation Flashcards
When do deciduous teeth start to erupt?
6 months old
What is the first primary tooth to erupt?
Mandibular central incisor
What is the second primary tooth to erupt?
Maxillary central incisor
What age have all the primary incisors erupted by?
9 months
When do the primary first molars erupt?
12-14 months old
What age does the primary canines erupt?
16-18 months
What age does the last teeth (second molars) erupt into the mouth and complete the primary dentition?
24-30 months
What age does the first permanent tooth erupt and which tooth is it?
First molar - 6 yrs
When does the first permanent incisor erupt?
7 yrs old
When does the second permanent incisor erupt?
8 yrs old
When does the first permanent premolar erupt?
9 yrs old
When does the second permanent premolar erupt?
10 yrs old
When do the permanent canines erupt?
11 yrs old
When do the permanent second molars erupt?
12 yrs old
When do the permanent third molars erupt?
18-25 yrs old
What are the morphological differences between primary and permanent teeth?
-Smaller
-Shorter crown
-Lighter colour - appears more white
-Thinner enamel and dentine
-Pulp horns are nearer the surface
-Pulp is relatively larger in regards to surrounding tooth
-Curved roots
-Contact points are flatter and wider
What is hypodontia?
Missing teeth as a result of them failing to develop
What is anodontia?
a genetic disorder defined as the absence of all teeth
What is ogliodontia?
Rare condition where more than 6 primary or permanent teeth are absent
What teeth are most commonly affected by hypodontia?
8s
5s
1s
What is the treatment for hypodontia?
Full/partial dentures
Implants
Composite advised to mask conical or mis-shaped teeth
What is hyperdontia?
an excess number of teeth beyond the expected 20 deciduous and 32 permanent teeth
(supernumerary)
Is hyperdontia more common in males or females?
males
What are mesiodens
a supernumerary tooth present in the midline or immediately adjacent to midline
What are paramolars?
a supernumerary molar usually small and rudimentary, most commonly situated buccally or palatally to one of the maxillary molars
What are distomolars?
a supernumerary tooth which is located distal to third molars
Is hyperdontia more likely to be seen in the maxilla or the mandible?
Maxilla
What is megadontia?
teeth larger than usual (big teeth)
What is an example of a case where megadontia may be seen?
cases of pituitary gigantism
What is microdontia?
teeth smaller than usual (small teeth)
What teeth are most commonly affected by microdontia?
maxillary lateral incisors and third molars
Is microdontia more common in males or females?
female
What is microdontia often associated with?
ectodermal dysplasia
down syndrome
What can cause disorders of root size?
-Racial variation - shorter roots seen in people of oriental backgrounds and larger roots in patients of African origin
-Irradiation of the jaws, or chemotherapy during root formation may lead to smaller roots
-Possibly ortho treatment
What is germination?
1 tooth germ splits into 2 teeth, with 1 root canal
What is fusion?
union of 2 normally separated adjacent tooth germs, with 2 canals
What is concrescence?
joining of 2 teeth by cementum (root surface)
What is dilaceration?
Gross disruption of root formation, remainder of tooth forms at an angle
What is the treatment for disorders of tooth formation?
Primary dentition - no tx]
Permanent dentition - depends on morphology of pulp chambers/root canals
What are invaginated teeth?
occurs when the palatal surface of the tooth enamel folds into the dentin during tooth development.
AKA - dens in dente (toot within a tooth)
pear shaped mass of enamel
Is the prevalence of dens in dente more common in males or females?
males
What is the treatment for invaginated teeth?
fissure seal soon after eruption
vitality test/radiograph
endo tx if pulp involvement
What are evaginated teeth?
small tubercle on occlusal surface of the premolar in the central part of the fissure pattern
What is the treatment for evaginated teeth?
radiographic evaluation to determine pulpal involvement (pulp horns in evagination)
restricted and repeated grinding of the tubercle, following by fissure sealant
removal of tubercle and limited pulpotomy may be required
What is a talon cusp?
horn like projection of the cingulum of the maxillary incisor teeth
what is the treatment for a talon cusp?
fissure seal margin
possible pulpotomy
no tx required if no interference with occlusion
What is taurodontism?
Bull like teeth
Molar teeth where the pulp chambers of the teeth are enlarged vertically at the expense of the roots
What is amelogenesis imperfecta?
Generalised term for enamel defects affecting all (or predominantly all) of the teeth of both the primary and permanent dentition,
effects ameloblasts
alters tooth colour
what are the 2 classifications of amelogenesis imperfecta
hypoplasia
hypomineralisation
what is enamel hypoplasia?
deficient enamel matrix resulting in thinner enamel, grooved or pitted, glossy, hard and translucent
what is enamel hypomineralisation?
defect in the mineralisation of the enamel, normal thickness but very soft, discoloured yellow-brown, opaque and chalky, prone to caries/enamel weak, enamel chips easily, poorly formed
what is dentinogenesis imperfecta?
an inherited disorder of dentine, effects odontoblasts, bluish tinge
what is congenital syphilis?
caused by spirocheate treponema pallidum, found in dental follicle. transmitted via placenta
what are the 3 anomalies found from congenital syphilis?
hutchinson’s incisors
mulberry molars
moon’s molars
what is hutchinson’s incisors?
affects upper central incisors
‘notch’ on incisal edge
mesio-distal narrowing or incisal edge
may lead to an anterior open bite
what are mulberry molars?
affects first permanent molars
occlusal surface is rough and pitted
looks like a raspberry/mulberry
what are moons molars?
affects first permanent molars
round or dome shaped
what are enamel pearls/enameloma?
small spherical enamel projection on a root surface (usually buccal)
often mistaken for calculus
what is fluorosis?
a condition that causes changes in the appearance of tooth enamel. It may result when children regularly consume fluoride during the teeth-forming years
what os tertracycline staining?
tooth discoloration occurs when tetracycline binds with the calcium needed for tooth development.
what affect does jaundice have on the oral cavity?
jaundice is a condition that can cause yellow or green discolouration of teeth due to an alteration of the dentin as teeth are forming.
what is molar incisor hypomineralisation?
a tooth condition where the enamel is softer than normal
