[PART 2] MODULE 12:CLEFT AND CRANIOFACIAL ANOMALIES AND DENTAL CONDITIONS

CLEFT

→ opening in anatomical part that is normally not opened 

→ developmental failure of fusion in the bony part of the lip and palate

→ congenital malformation → non-fusion of musculoskeletal structures 

ANATOMY OF THE PALATE

→ lip, premaxilla, alveolar ridge (gum), hard palate, soft palate, uvula

NASAL ROOT

Starting point of the nose at the level of the eyes

NASAL BRIDGE

Bony structure between the eyes; corresponds with the nasofrontal suture

COLUMELLA

Tissue between the nostrils under the nasal tip

NARES

Nostrils

ALA NASI

Curved side of the nostril

THE NEURAL CREST CELL THEORY

→ composed of ectoderm 

→ cells migrate to designated areas at different rates → connective and neural tissues of the skull, branchial arches, face

→ cells that form the frontonasal process arise from the forebrain → rise to nose and adjacent structures

→ cells that form right and left maxillary processes and mandible come from the lateral portion of the face 

→ Mesenchymal tissues: formed by migrating cells provides for most of the bone and soft tissue of the face 

→ Disruption, interruption or failure of migration of cells to reach areas on time and absence or inadequacy of mesoderm = clefting may occur

 Mesenchymal tissues

formed by migrating cells provides for most of the bone and soft tissue of the face

CHROMOSOMAL AND GENETIC FACTORS

→ clefts occur d/t delays in cell migration and/or palatal shelf movement 

These are caused by:

• Chromosomal

• Genetic disorders 

→ increased paternal age has been linked to an increased risk for cleft lip and palate 

→ genetics: hereditary, the way we act and think

→ blood compatibility of father and mother is spot on

ENVIRONMENTAL TERATOGENS

→ teratogens: substances that cause congenital malformation 

• Cigarette smoke, anti convulsant drugs (Dilantin, thalidomide, valium, lead and lead pollution)

→ systemic corticosteriod treatment

→ certain viruses (rubella, influenza) 

→ maternal nutritional deficiencies (Vitamin B-6, Folic Acid) 

→ maternal obesity: increase risk for orofacial clefts 

→ pregnant → take in your body → goes to child

TIMING OF EMBRYOLOGICAL FUSION

→ Evidence shows a difference in the timing of embryological fusion among males and females in relation to the type of cleft 

→ Cleft lip (with or without cleft palate) occurs twice as much in females than in males

→ Burdi & Silvey: horizontal positioning and closure of the palate occur earlier in males > females

• Secondary palate is open longer: among females during dev → susceptible to environmental teratogens → more cleft palates

MECHANICAL INTERFERENCE

→ crowding of the uterus 

→ dorsal positioning of the head and retraction of mandible → prevents tongue from dropping down from oral cavity 

→ mother has a small uterus

PREVALENCE

→ 4th most common birth defect and the most common congenital defect of the face 

→ infants: 10 in 10,000

→ 0.2 to 0.5 per 1000 births 

→ 1 in 1000 live births 

→ 5:100 in the Philippines

SIGNS AND SYMPTOMS

→ crooked, poorly shaped, missing teeth  → misalignment of teeth, jaw → deformities in the maxilla  → speech problems

→ unrepaired oronasal fistula  → alveolar clefts → submucous cleft palate

PRIMARY PALATE

→ structures that are anterior to the incisive foramen (triangular segment: fusion happens here)

→ fuse around 7 weeks of gestation alveolus and also the lip

—> fuse around 7 weeks of gestation alveolus and also the lip

SECONDARY PALATE

→ structures that are posterior to the incisive foramen 

→ fuse around 9 weeks of gestation

→ hard palate and the velum

—> Base of the Y submucous cleft, the affected segments are marked with crosshatch marks

LATERALITY

Unilateral or bilateral

COMPLETENESS

Complete or incomplete

STRUCTURE

Primary or secondary palate

PROLABIUM

→ ball-shaped tissue that is bilateral cleft and palate usually seen during bilateral cleft lip and palate 

→ did not fuse, did not migrate properly

CLEFT LIP

→ not missing, but the structures did not develop

—> unilateral

CLEFT LIP-BILATERAL

CLEFT LIP - RIGHT

CLEFT LIP - LEFT

CLEFT PALATE

Bilateral

→ cleft of the secondary palate structures posterior to the incisive foramen (uvula and usually the velum with hard palate)

→ can occur with or without cleft lip 

→ can be complete or incomplete

CLEFT LIP AND PALATE

incomplete

SUBMUCOUS CLEFT

Complete, most challenging, still requires surgery, nothing wrong visually

COMPLETE CLEFT LIP

→ extends through entire lip, nostril, alveolus

→ complete cleft of the primary palate, anterior position at birth (appear to extend from the tip of the nose) 

→ extends to the floor of the mouth

INCOMPLETE CLEFT LIP

→ cleft does not extend to the incisive foramen 

→ can be as minor as a small, subcutaneous notch in the vermilion

→ may involve the entire lip and part of alveolus

UNILATERAL CLEFT LIP

→ occurs on one side of the lip most often occurs on the left side

BILATERAL COMPLETE CLEFT LIP

→ complete separation of the tissue that would normally form the philtrum prolabium notch in the vermillion

→ may involve the entire lip and part of the alveolus

ANATOMY OF THE PALATE

Primary palate

Incisive foramen

Secondary palate

Hard palate

Soft palate

Alveolar ridge

CRANIOFACIAL ANOMALIES

Facial features are not aligned; did not migrate at the right time | unilateral or bilateral midline cleft | other clefts: d/t failure of neural crest cell migration (severe & rare) | accompanied by many other anomalies

PIERRE ROBIN SEQUENCE

→ Bird’s view 

→ MICROGNATHIA: undersized lower jaw in children that can cause an overbite

→ GLOSSOPTOSIS: tongue is displaced backward and downward, potentially obstructing the airway 

→ cleft palate worsens respiratory effort of feeding; disrupt suck-swallow-breathe

MOEBIUS SYNDROME

→ genetic disorder 

→ weakness or lack of movement in the lips, chronic, open mouth posture

→ high palatal vault 

→ excessive drooling and anterior loss of formula

→ restricted range of movement (jaw, lips, tongue)

HEMIFACIAL MICROSOMIA

→ various: mandibular hypoplasia, facial weakness, limitations to the range of motion

→ Microsomia: body structures are abnormally small 

→ Migration: because features are complete, but there is an abnormality in the genetic make-up

BECKWITH-WIEDEMANN SYNDROME

→ macroglossia

→ omphalocele (abdominal wall defect)

→ hypoglycemia 

→ abnormalities of the kidneys, pancreas, and adrenal cortexa genetic disorder (causing prenatal and postnatal overgrowth) 

→ a lot of internal organ issues aside from possible craniofacial anomalies

OROFACIODIGITAL SYNDROME TYPE I (OFD I)

→ x-linked dominant condition 

→ midline cleft lip with multiple oral frenulae 

→ lip pits 

→ velocardiofacial syndrome (VCF)

MICROGNATHIA

undersized lower jaw in children that can cause an overbite

GLOSSOPTOSIS

tongue is displaced backward and downward, potentially obstructing the airway

Microsomia

body structures are abnormally small

Migration

because features are complete, but there is an abnormality in the genetic make-up