Developmental anomalies of the
teeth, specific and non – specific
disorders of hard dental tisuess
6 DM
Developmental anomalies
- tooth development is strict under genetic control
- disturbances in tooth development result from
gene mutation
- tooth development may be disturbed at different
stages of morphogenesis
- definitive result depends on the timing and the
type of insult
Developmental anomalies
Disturbances in tooth development:
 numerical variations (missing or supernumerary
teeth)
 variations in size of teeth
 variations of shape of teeth
 disturbances in eruption
Developmental anomalies
Numerical variations
1.Hypodontia
- number of teeth is decrease
- the most commonly missing teeth are:
the third molars, second premolars, maxillary
lateral incisors
- oligodontia, anodontia, agenesis
Developmental anomalies
Numerical variations
1.Hypodontia in deciduous dentiotion:
- prevalence 0.1 – 0.7%
- central incisors
- oligondontia and anodontia is rare, may be found
in connection with ectodermal dysplasia
Developmental anomalies
Ectodermal dysplasia:
- describes a group of developmental, often
inherit, disorders involving the ectodermally
structures(hair,teeth, nails, skin and sweat glands)
- presentation:multiple missing teeth, fine, sparse
hair, dry skin, maxillary hypoplasia, eversion of
the lips, pigmentation around the mounth and eyes.
The teeth are conical, small, often with a large
diastema.
Developmental anomalies
Numerical variations
1.Hypodontia in permanent dentiotion:
- prevalence 6 – 10%
- usually affects 2 or more teeth in 50% of the
cases
- often occures symmetrical hypodontia
- particular relation with the microdontia
Developmental anomalies
Solitary median maxillary central incisor syndrome
- is very rare
- midline symetrical maxillary central incisor
- can be associated with cleft palate, choanal
stenosis, umbilical hernia, hypoplasia of sella
turcica, pituitary dysfunction, growth hormone
deficiency
Developmental anomalies
Numerical variations
2. Hyperodontia
- number of the teeth is increse
- is quite rare as hypodontia
Frequency: primary teeth 0,3 - 0,8%
permanent teeth 1,0 – 3,5%
Developmental anomalies
Numerical variations
2. Hyperodontia
- shape is conical or normal
- supernumerary teeth can erupt or cause
anomalous eruption of neighbouring teeth
- most frequent is mesiodens
- part of syndrom cleidocranial dysplasia
Developmental anomalies
Cleidocranial dysplasia:
- short stature
- aplasia or hypoplasia of clavicles
- delayed ossification
- delayed eruption of teeth
- dentigerous cyst formation
Developmental anomalies
a) Dentes praelactales
-
frontal region in a newborns
-
no roots
Th: extraction
Developmental anomalies
Variations in tooth size:
1. Macrodontia
-
teeth are larger than normal
-
true macrodontia involving the whole dentition
2. Microdontia
-
one or more teeth are smaller than normal
-
most affect the maxillary third molars
General microdontia: is a rare conditionoccuring in
connection with congenital
Local microdontia: involving single teeth, associated
with hypodontia
3. Rhizomicry
-lenght of the root is shorter than the height of
the crown
-connected with osteoporosis
- predominantly affecting maxillary incisors and
premolars
Developmental anomalies
Variations on tooth shape
1. Dens invaginatus
-
malformation due to an invagination of enamel
epitelium resulting in a chanel or lumen
surrounded by hard tissues within the tooth.
The anomaly occurs most frequently in the
palatal surface of max. lateral incisor.
2. Conical peg-shaped tooth
Developmental anomalies
Variations on tooth shape
3. Taurodontism
-
elongated root- stem with the furcation more
apical than normally
4. Double formation of teeth
a) concrescence- two normal appearing crowns are
present and the fusion involves only the
cementum
Developmental anomalies
Variations on tooth shape
b) Fusion – union in dentin and/or enamel between
two or more normal teeth
c) Gemination – incomplete division of a tooth germ
or a union between normal and a supernumerary
tooth
5. Dnes evaginatus
- is an extra cusp, usually in the central groove or
ridge of a posterior teeth and in the cingulum of
the central or lateral incisor
Developmental anomalies
6. Dens in dente
-
is a condition resulting from invagination of the
inner enamel epithelium producing the appearance
of a tooth within a tooth
7. Dilaceration
- an abnormal bend of the rooth during its
development and is thought to result from a
traumatic episode
Developmental anomalies
Variations in tooth eruption
a) tooth retention
b) tooth semiretention
c) anomalous position after eruption
Non – specific disorders of hard dental tisuess
1) Hypoplasia
2) Hypomineralization
Hypoplasia:
Ethiology:- metabolic disorders, fever, endocrinic
disease,trauma, inflammation
Cl. picture: anomalous shape of dental crown,
grooves and fissures, color-dark brown,
yellowbrown.
Non – specific disorders of hard dental tisuess
Hypomineralization:
Ethiology:- metabolic disorders, fever, endocrinic
disease,trauma, inflammation
Cl. picture: normal shape of dental crown, in hard
dental tisuess are quality changes. Color- white
or brown smudges, localization on labial surfaces
of incisors
Specific disorders of hard dental tisuess
Dysplasia of hard dental tisuess
1.DENTIN DYSPLASIA
Ethiology: ingestion of chemicals, prematurity
birthweight, severe malnutrition, bilirubinemia
Typ I: radicular dentin dysplasia or rootless tooth
Typ II: anomalous dysplasia of dentin with frequent
discoloration of primary teeth, permanent teeth
often appear normal clinically but have thistletube formed pulp chamber. Pulp stones may
occure.
Specific disorders of hard dental tisuess
Chronic toxicity
2.Dental
Fluoride
induced defect
fluorosis
Dental fluorosis is a qualitative defect of enamel, resulting
from an increase in concentration within the F
microenviroment of the ameloblasts during enamel
formation
Manifestation
• very mild
white flecks
• mild-fine
white lines
• moderate
very chalky, opaque enamel
• severe
outher enamel
mottling and loss of proportion of the
Specific disorders of hard dental tisuess
3. Tetracycline defects
- TTC has a strong affinity to mineralized tisuess,
primary to dentin and bones
-
dentin defects are persistent
-
discolored horizontal bands may appear gray,
bluish
-
discolored enamel has some translucency left
-
this ATB shoud not be prescribed to children
below the age of 8, pregnant women, lactating
mothers
Specific disorders of hard dental tisuess
4. Molar – incisor hypomineralization
-
demarcated opacities in the perm. first molars,
perm. incisors are often also involved
-
may affect one or all molars and one or more
incisors
-
creamy white spot to yelowish brown
discoloration
-
defect are porous
Specific disorders of hard dental tisuess
Subj. symptoms:
-
shooting pain during brushing teeth or breathing
cold air
Ethiology:
- unknown, but suggestion are: medical problem
related to birth, respiratory diseases during
first 3 years of life
Specific disorders of hard dental tisuess
Amelogenesis imperfecta
Definition:AI represents a roup of condition,
genomic in origin, which affect the structure and
clinical appearance of the enamel of all or nearly
all teeth in a more or less equal manner, and
which may be associated with morphologic or
biochemical changes elsewhere in the body.
Specific disorders of hard dental tisuess
- autosomal dominant, autosomal recessive
-
incidence 1 in 14 000
-
4 major categories, 14 subtypes
General manifestation:
-
normal intelligence, good general health
Craniofacial/dental manifestation:
-
enamel defect that affects both dentitions,
appearance is yellow- brown to orange depending
on subtyp
Specific disorders of hard dental tisuess
Typ I:- hypoplastic (occuring in the histodifferation
stage of tooth development, insufficient quantity
of enamel is formed)
TypII:- hypomaturation (defect of in enamel
matrix apposition)
Typ III:- hypocalcified (enamel is normal, but
qualitatively the matrix is poor calcified with a
resultant fracturing of the enamel surface.
Hypocalcified enamel is soft and fragile,
especially at the incisal region, and is easily
fractured, exposing dentin.
Specific disorders of hard dental tisuess
Typ IV:- hypomaturation, hypoplastic with
taurodontism (the enamel appears mottled with a
yellow-brown color and is pittedon the facial
surfaces. Molar teeth demonstrate
taurodontism.
Specific disorders of hard dental tisuess
Dentinogenesis imperfecta
Defect of predentin matrix that result amorphic,
disorganized, and atubular circumpulpal dentin.
-
incidence 1 in 8000
-
3 basic types
Shields type 1
Shields type 2
Shields type 3
Specific disorders of hard dental tisuess
Shields type 1
-
occurs with AI
-
inherit defect in collagen formation
-
osteoporotic brittle bones
-
bowing of the lips
-
blue sclera
-
bitemporal bossing
-
obliteration of pulp chamber,periapical
radiolucencies, bulbous crowns, root fractures
Specific disorders of hard dental tisuess
Shields type 2
-
hereditary opalescent dentin
-
autosomal dominant
-
affect primary and permanent dentition
Shields type 3
-
is rare, bell-shaped crown,
-
it has occured exclusively in a triracial isolated
group in Maryland
Specific disorders of hard dental tisuess
Specific disorders of hard dental tisuess