The document discusses teratogens, which are substances that can cause congenital abnormalities during fetal development. Key factors include genetic history, environmental exposure to radiation, cigarettes, chemicals, drugs, and alcohol, with critical periods noted during the first eight weeks of embryogenesis. Malformations such as facial clefts and anencephaly are highlighted, along with specifics on types of cleft lips and their causes.

1. PRESENTED BY :-
SYEDA FATIMA NAQVI
DOW INTERNATIONAL DENTAL COLLEGE KARACHI
PAKISTAN

2. Teratogens are substances or
other factors that can cause
congenital abnormalities(
functional or structural),which are
also called as birth defects in an
organism exposed during a fetal
life.

3.  Genetic factors
(family history )
 Radiation
 Cigarettes
 Chemicals
 Drugs
 Alcohol

4.  The timing of an environmental factors can
be critical during first 4 weeks of
embryogenesis.
 Because embryo is developing rapidly and
any teratogenic factor can lead to fetal
death
 During 4th to 8th week of embryogenesis ,
histodifferentiation and organ
differentiation takes place and teratogenic
agents are more likely to produce
malformations.
 These malformations includes:-
 Facial Clefts , Anencephaly, cervical rib

5.  Unilateral cleft lip
 Bilateral cleft lip
 Median cleft lip
 Oblique facial
cleft
 Median cleft
 Lateral facial
cleft
 Mandibular cleft

6.  Bilateral cleft lip:-
Results from lack of fusion between
maxillary Process and median nasal
process.
 Median cleft lip :-
Lack of fusion between 2 medial nasal
process
 Oblique facial cleft:-
Lack of fusion between the maxillary
Process and lateral nasal process

7.  Macrostoma:-
It is a poor merging of maxillary
and mandibular process.
 Microstomia:-
It is an excessive merging of
maxillary and mandibular
process.

8.  A- Normal
 B- Cleft of lip
 C- Primary palate
 D- Unilateral cleft lip
and palate
 E- Bilateral cleft lip
and primary
palate
 F- Bilateral cleft lip
and
palate