Lip cleft

University of kirkukCollege of dentistry

Oral Histology

Lip Cleft

Dr. Asmaa sedeek

Definition

A cleft lip or palate is an abnormal separation in the oral-facial region that happens because tissue of the mouth or lip does not form correctly in fetal development.

Anatomic Principles

A- Normal Lip consists of:

1) Central Philtrum

It is consists of:
Lateral margins - philtral columns
Inferior border - Cupids bow and tubercle


2) Vermillion-cutaneous border

Embryology of Clefting

Facial Development - 4th - 10th week of development

Formed by the fusion of five prominences

Unpaired frontonasal process

Paired maxillary swellings

Paired mandibular swelling






Cleft Variants
Great anatomic variation in types of clefts!

Anatomic Classification based on:

1) Location
2) Completeness (Incomplete/Complete)
3) Extent

Since lip, alveolus, and hard palate differ in embryologic origin, any combination can occur

Classification

Standardized methods
Key anatomic structure
Incisive foramen
Primary palate
Lip
Premaxilla
Alveolus
Secondary palate
Soft palate
Hard palate

Cleft of primary palate (cleft lip)

Unilateral
Incomplete
Lip only
Complete
Primary palate
Lip, nasal floor, alveolus

Result from deficiency of mesenchyme in the maxillary prominences and intermaxillary segment

Cleft of primary palate (cleft lip)

Bilateral
Incomplete
Lip only
Complete
Primary palate
Lip, nasal floor, alveolus





Cleft of secondary palate- Soft palat only (incomplete cleft palat) Soft and hard palat (complete cleft palat) Submucus cleft
• Caused by defective development of the secondary palate and result from the growth distortions of the lateral palatine processes (shelves) which prevent their medial migration and fusion

Epidemiology

Cleft lip and palate
Racial heterogeneity
Asians
2.1 in 1000 live births
Whites
1 in 1000 live births
African Americans
0.41 in 1000
Isolated cleft palate
Constant incidence
0.5 in 1000 live births

Environmental agents

Chemical agents


Alcohol
No increased risk of cleft with low quantities of EtOH
Increased risk of clefting with higher quantities of EtOH

Dilantin , sodium valproate, benzodiazepines and corticosteroids.

10X higher risk of cleft lip

Smoking

Dose response relationship
Increased risk of clefting

Environmental agents

Folic acid
Beneficial effect
Reduced incidence of unilateral cleft lip and palate with at risk mothers
Isotretinoin
Accutane dysmorphic syndrome
Rudimentary external ears
Absent/imperforate auditory canals
Triangular microcephalic skull
Cleft palate
Depressed midface
Brain/jaw/heart anomalies


Treatment
Treatment involves many things which include plastic surgery, orthodontics, and speech therapy

Other facial anomalies

• Median clefts (rare)
Upper
• Mesenchymal deficiency causing partial or complete failure of medial nasal prominences to merge and form the intermaxillary segment
Lower
• Failure of mesenchymal masses in the mandibular prominences to merge completely and smooth out the embryonic cleft between them

Facial clefts

Macrostomia

Microstomia

Failure of fusion between maxillary process and lateral nasal process

Failure of fusion between maxillary process and mandibular process
Over fusion between maxillary process and mandibular process
Done by: Asmaa Aljumaily