2

Developmental Disturbances of the Teeth

Dr. BUSHRA RASHID NOAMAN

objectives

1. Types of anomalies

• The cause of each anomaly

• The time the anomaly happen during tooth development

. Types of anomalies

A. Anomalies of number.
B. Anomalies of size.
C. Anomalies of shape.
D. Anomalies of structure.

A. Anomalies of number.

1. increase in number (Supernumerary tooth or hyperdontia)
Rudimentary supernumerary, conical form.
2. Decrease in number Congenital absence (hypodontia)
Missing maxillary left lateral

WHAT IS THE REASON?

HYPERDONTIA OR SUPERNUMERARY
Reasons :
• continue budding of enamel organ
• the cells become more fully differentiated and detached from the enamel organ
HYPODONTIA OR LESS NO. OF TEETH

deficiency in initiation and proliferation

B. Anomalies of size.
1. Microdontia (smaller than normal

2. Macrodontia bigger than normal

What is the reason?

Disturbances and aberrations in morphodifferentiation stage

C. Anomalies of shape.

2. Dens in dent

Upper lateral incisor with invagination

1. Talon cusp

Reasons
Disturbances in

morphpdifferentiation stage

2. Fusion: two teeth fused with two pulps

3. Gemination: wide crown with one pulp

Reasons

Fusion
Fusion of two tooth germs during

Proliferation stage

Gemination
an attempted division of a single tooth germ by invagination occurring during the
proliferation stage

4. Dilacerated tooth

Reason
Trauma affecting the tooth bud during root formation




D. Anomalies of structure.
1. Enamel hypoplasia

Enamel matrix deffect

Reason of enamel hypoplasia
Enamel matrix deffect

Defect in formation of some of the ameloblast cells during the histodifferentiation stage

Enamel hypocalcification

a lack of fusion of the calco-spherites.
During the calcification process


2. Amelogenesis imperfecta
.

4. Dentinogenesis imperfecta.

Reasons

Amelogenesis imperfecta
Disturbances of the differentiation of the formative cells which are ameloblasts
during histodifferentiation stage
Dentinogenesis imperfecta
Disturbances of the differentiation of the formative cells which are odontoblast
during histodifferentiation stage


Difference between amelogenesis imperfecta and Dentinogenesis imperfecta
Amelogenesis imperfect
Normal root
Dentinogenesis imperfect
Abnormal root

5. Dental fluorosis

Excessive fluoride consumption during tooth development during apposition or calcification stage

6. Tetracycline stain

Tetracycline medication given to the child before 12 years old affecting the tooth development
During the apposition stage or calcification stage