Developmental disturbances of the teeth (loạn dưỡng hệ răng)

bài giảng loạn dưỡng hệ răng cho sinh viên nha khoa.

L DISTURBANCES

OF THE TEETH

Prepared by:

Dr Rea Corpuz

 Microdontia

 Macrodontia

Size

 Microdontia

 (1) True Generalized

Microdontia

 (2) Relative Generalized Microdontia

 (3) Focal or Localized

Microdontia

Siz

e

 all teeth are smaller than normal

 occur in some cases of pituitary dawrfism

 normal or slightly smaller than

 common forms of localized microdontia is that which

affects maxillary lateral

 sides converge or taper together incisally

 forms cone-shaped crown

 root is frequently shorter than usual

(3) Focal/Localized

Microdontia

 Microdontia

 Macrodontia

Size

 Macrodontia

 (1) True Generalized

Macrodontia

 (2) Relative Generalized Macrodontia

 (3) Focal or Localized

Macrodontia

Siz

e

 all teeth are larger than normal

 normal or slightly larger than normal teeth in small jaws

 Supernumerary

 results from continued

proliferation of

permanent

or primary dental lamina

to form third tooth germ

 teeth may have:

• normal morphology

• rudimentary

• miniature

Number and Eruption

 Supernumerary

 more often in permanent

dentition than primary

• prevent their eruption

Number and Eruption

 Supernumerary

 many are impacted

• characteristically found

in cleidocranial dysostosis

Number and Eruption

 small tooth

 cone-shaped crown

 short root

Mesiodens

 2nd most common

 situated distal to 3rd molar

 small rudimentary tooth,

but may be of normal size

 mandibular 4th molar also is seen occasionally, but less common than maxillary

molar

Fourth Molar

 small + rudimentary

 situated bucally or lingually

to one of the maxillary

molars

 interproximally between 1st

+ 2nd or 2nd + 3rd maxillary molars

Paramolar

 molar located distal to molar

Distomolar/Distoden s

 when all teeth are missing

 lack of development of one or more teeth

Hypodonti

a

 lack of development of six or more teeth

Oligodonti

a

 when teeth are absent clinically because of impaction or delayed eruption

Pseudoanodonti a

 when teeth have been exfoliated or extracted

False Anodontia

Number and Eruption

 Impaction

 Ankylosis

Number and Eruption

 cause fusion of tooth to alveolar bone

Ankylosis

 Crown

 Root

Shape and Form

 joining of 2 developing

tooth germs

 resulting in a single

large tooth structure

 may involve entire length

of teeth

 or may involve roots only,

in which case cementum + dentin are SHARED

Fusion

 fusion of 2 teeth from a

single enamel organ

 partial cleavage

 appearance of 2 crowns

that share same root canal

 trauma has been suggested

as possible cause, the cause is

still unknown

Gemination

 variation in tooth form:

 elongated crowns

 apically displaced

furcations

• resulting in pulp chambers that have apical occlusal height

Taurodontis

m

 may bee seen as isolated incident in families

 associated with syndromes such as

 Down syndrome

 Klinefelter’s syndrome

Taurodontis

m

 little clinical significance

 No treatment is required

Taurodontis

m

 Talon’s Cusp

 Leung’s Premolar

Dens

Evaginatus

 well-delineated additional cusp

 located on the surface of

 developmental condition

 clinically as an accessory cusp

 deep surface invagination

of crown or root that is lined

 depth varies from slight

enlargement of cingulum

to a deep infolding that

extends to apex

 historically, it has been

classified into 3 major types:

• ends in a blind sac

• may or may not

communicate with adjacent dental pulp

Dens

Invaginatus

(Dens in Dente)

pulp

Dens

Invaginatus

(Dens in Dente)

 undersized lateral incisor

 smaller than normal

 occurs when permanent

lateral

incisors do not fully develop

Peg-Shaped

Lateral

Peg-Shaped Lateral

 characteristic of congenital syphilis

 lateral incisors are

 notches on their biting surfaces

 named after Sir Jonathan Hutchinson

 English surgeon +

pathologist who 1st described it

Hutchinson’s Incisor

 dental condition usually

associated with congenital syphilis

 characterized by multiple rounded rudimentary

enamel

cusps on permanent 1st

molars

Mulberry Molar

 dwarfed molars with cusps covered with globular

 2 fully formed teeth

 joined along the root

surfaces

by cementum

 noted more frequently in posterior and maxillary regions

Concrescence

 often involves a 2nd molar

tooth in which its roots

closely approximate the

adjacent impacted 3rd molar

 may occur before or after the teeth have erupted

 usually involves only 2 teeth

Concrescence

 diagnosis can frequently be established by

roentgenographic

examination

 often requires no therapy

unless union interferes with eruption; then surgical

removal may be warranted

since with fused teeth,

extraction of one may result in

extraction of the other

Concrescence

 droplets of ectopic enamel

 or so called enamel pearls

 may occasionally be found on roots of teeth

 occur most commonly in

bifurcation or trifurcation

of teeth

 may occur on single-rooted premolar as well

 maxillary molars are

commonly affected than mandibular molars

Enamel

Pearls

 consist of only a nodule

of enamel attached to dentin

 may have a core of dentin containing pulp horn

 may be detected on

radiographic examination

Enamel

Pearls

 may cause stagnation at gingival margin but, if they contain pulp, this will

be exposed when pearl is removed

Enamel

Pearls

 angulation or a sharp

bend or curve in root

or crown of a formed tooth

 movement of crown or

of the crown and part of root from remaining developing root may result in sharp

angulation after tooth

completes development

Dilaceration

 hereditary factors are

believed to be involved

in small number of cases

 eruption generally continues without problems

Dilaceration

 deviation or bend restricted just to the root portion

 usually bend is less than 90 degrees

 may be a result of trauma to the developing tooth

Flexion

 have become ankylosed

to bone

 this process prevents their exfoliation + subsequent replacement by

 also known as:

 group of conditions caused by

defects in the genes

encoding

enamel matrix proteins

 genes that encode for enamel proteins:

 amelogenin mutated in

 affects both dentition

 No treatment except for improvement of cosmetic appearance

Amelogenesis

Imperfecta

 reduced enamel thickness

 abnormal contour

 absent interproximal

contact points

 Radiographically:

 enamel reduced in bulk

 shows thin layer over

occlusal

+ interproximal surfaces

Hypoplastic

Amelogenesis Imperfecta

 dentin + pulp chambers

appear normal

 no treatment is necessary

Hypoplastic

Amelogenesis Imperfecta

 enamel is normal in form on

eruption but:

 opaque

 white to brownish-yellow

 softer than normal

 tends to chip from

underlying

dentin

Hypomaturation

Amelogenesis Imperfecta

 enamel matrix is formed in

normal quantity

 poorly calcified

 when newly erupted:

 enamel is normal in thickness

 with years of function:

 coronal enamel is removed

 except for cervical portion

that is occasionally calcified

 also known as “Hereditary

 have blue to brown

discoloration

 with distinctive translucence

 enamel frequently separates

easily from underlying defective dentin

Dentinogenesis

Imperfecta

 Treatment:

 prevent loss of enamel + subsequent loss of dentin through attrition

 cast metal crowns on

 occurs in families with

Osteogenesis Imperfecta

 primary teeth are more severely affected than permanent teeth

Type I Dentinogenesis Imperfecta

 Radiographically:

 partial or total obliteration

of pulp chambers + root

 never occurs in association

with osteogenesis imperfecta

unless by chance

 most frequently referred to as

hereditary opalascent dentin

 only have dentin abnormalities and no bone disease

Type II Dentinogenesis Imperfecta

 Radiographically:

 partial or total obliteration

of pulp chambers + root

 “Bradwine type”

 racial isolate in Maryland

 multiple pulp exposures in deciduous not seen in type

 enamel appears normal

 large size of pulp chamber

is due not to resorption but

rather to insufficient + defective dentin formation

Type III

Dentinogenesis

Imperfecta

 also known as “Rootless Teeth”

 rare disturbance of dentin

formation

 normal enamel

 atypical dentin formation

 abnormal pulpal morphology

 hereditary disease

Dentin

Dysplasia

 Classification:

 Type I (Radicular Type)

 Type II (Coronal Type)

Dentin

Dysplasia

 both dentitions are of

 Radiographically:

 roots are extremely short

 pulps almost completely obliterated

 color of primary dentition

is opalescent

 permanent dentition is normal

 coronal pulps are usually large (thistle tube appearance)

 filled with globules of

abnormal

dentin

Type II (Coronal Type)

 Radiographically:

(Deciduous)

 roots are extremely short

 pulps almost completely

obliterated

(Permanent)

 abnormally large pulp

chambers in coronal portion of

tooth

Type II (Coronal Type)

 also known as:

 one or several teeth in a

localized area are affected

 maxillary teeth are involved more frequently than

 teeth affected may exhibit

a delay or total failure in eruption

 shape is altered, irregular

in appearance

Regional

Odontodysplasi

a

 normal thickness enamel

 extremely thin dentin

 enlarged pulps

 thin dentin may involve

entire tooth or be isolated

to the root

 most frequently in deciduous

Shell Tooth

 Books

Oral Pathology and Oral Medicine,