Notes on Developmental defects of the oral and maxillofacial regions

Developmental defects of the jaws

1. Orofacial clefts
2. Coronoid hyperplasia
3. Condylar hyperplasia
4. Condylar hypoplasia
5. Bifid condyle
6. Exostoses
7. Torus palatinus
8. Torus mandibularis
9. Eagle syndrome
10. Stafne defect
11. Hemihyperplasia
12. Progressive hemifacial atrophy
13. Segmental odontomaxillary dysplasia
14. Crouzon syndrome
15. Apert syndrome
16. Mandibulofacial dysostosis
17. Pierre Robin syndrome

Orofacial clefts

• Most common major congenital defects in humans
• Frequency of CL +/- CP : Native americans,Asians, Whites,Blacks
• CL+CP 45%, CPO 30%, CLO 25%
• More common in males than in females
• CL: 80%-unilateral (70%-left side), 20%-bilateral
• 70% of unilateral CLs are associated with CP
• Minimal manifestation of CP is a bifid uvula
• Submucosal palatal-the surface mucosa is intact, but adefect exists in the underlying musculature of the soft palate

 

Coronoid hyperplasia

• Rare, unknown cause
• Male-to-female ratio = 5:1
• Endocrine influence, heredity
• Bilateral CH is more common than unilateral CH*
• Restricts mandibular opening and causes deviation towardaffected side*

Condylar hyperplasia

• Excessive growth of one of the condyles
• Endocrine disturbances and trauma
• Facial asymmetry, prognathism, crossbite and open bite
• Most commonly found in adolescents and young adults
• Self limiting condition

Condylar hypoplasia

• Underdevelopment of the mandibular condyle
• Congenital
•    (mandibulofacialdysostosis, hemifacial microstomia)
• Acquired
•   (trauma to thecondylar region during infancy or childhood, infection, radiation therapy, RA,OA)

Bifid condyle

• Double-headed mandibular condyle
• Medial and lateral head divided by an anteroposterior groove
• Trauma, abnormal muscle attachment, teratogenic agents,persistence of a fibrous septum within the condylar cartilage
• Popping or clicking sound when opening the mouth

Exostoses

• Localized bony protuberances that arise from the corticalplate
• Adults
• A bilateral row of bony hard nodules along the facial aspectof the maxillary and mandibular alveolar ridge

Torus palatinus/mandibularis

Torus palatinus

• Common exostosis that occurs in the midline of the vault ofthe hard palate
• Genetics vs environmental or both
• Asian and Inuit
• Female:Male = 2:1

Torus mandibularis

• A bony protuberance along the lingual aspect of the mandibleabove the mylohyoid line in the region of the premolars
• Bilateral
• May appear on periapicalradiographs as a radiopacity superimposed on the roots of the tooth

Eagle syndrome

• Elongation of the styloid process or mineralization of thestylohyoid ligament complex
• Adults, Most commonly unilateral
• Vague, radiated facial pain while swallowing, turning thehead or opening the mouth
• Classic Eagle syndrome – After tonsillectomy
• Stylohyoid syndrome – impinge on the internal or externalcarotid arteries and associated sympathetic nerve fibers

Stafne defect

• An asymptomatic radiolucency below the mandibular canal inthe posterior mandible, between the molar teeth and the angle of the mandible
• Typically well-circumscribed with a sclerotic border
• Mostly unilateral
• Reported in middle-aged and older adults, children is rarelyaffected
• Normal submandibular gland tissue
• No treatment required

Hemihyperplasia

• Asymmetric overgrowth of one or more body parts (right side)
• 2:1 female-to-male predilection
• Asymmetry may be noted at birth
•  The enlargementbecomes more accentuated with age especially atpuberty
• Skin on the affected side: thickened, increasedpigmentation, hypertrichosis, telangiectasias or nevus flemmeus
• Oral: Macroglossia, larger mandibular canal-crowns
• Differentiated from Proteus syndrome, NF1

 

Progressive hemifacial atrophy

• Atrophic changes affecting one side of the face
• ?trophic malfunction of the cervical sympathetic nervoussystem, trauma, hereditary
• Close relationship with localized scleroderma
• Starts during the first 2 decades of life
• Atrophy of the skin and subcut. Affecting the dermatome ofCNV, osseous hypoplasia
• Oral: mouth deviated toward the affected side, unilateralatrophy of the tongue, unilateral posterior open bite, deficient root formationor resorption

Segmental odontomaxillary dysplasia

• Childhood
• Painless, unilateral enlargement of the maxillary bone alongwith fibrous hyperplasia of the overlying gingival soft tissues
• Missing developing maxillary premolars, hypoplastic primaryteeth
• X-Ray: thickened trabeculae-relatively radiopaque, granularappearance

Crouzon syndrome

• Craniosynostosis : premature closing of the cranial sutures
• FGFR2 gene mutation on chromosome 10q26
• Brachy-scapho-trigonocephaly
• Shallow orbit-visual impairment or total blindness
• Headaches, beaten metal skull
• Underdeveloped maxilla

Apert syndrome

• Characterized by craniosynostosis
• FGFR2 gene on chromosome 10q26
• Autosomal dominant, paternal origin
• Tower(clover leaf) skull, ocular proptosis withhypertelorism, visual loss, hypoplastic middle face – mandibular prognathism,open- mouth appearance, syndactyly*, mental retardation, cleft soft palate

Mandibulofacial dysostosis

• Defects of structures derived from the first and secondbranchial arches
• Autosomal dominant
• TCOF1 gene mapped to chromosome 5q32-q33.1
• Hypoplastic zygoma, narrow face, depressed cheeks, coloboma, tongue-shaped sideburns, anomalies ofears, underdeveloped mandible

Pierre Robin syndrome

• Triad: CP, mandibular micrognathia and glossoptosis
• The retruded mandible results in: Posteriordisplacement of the tongue
  

                                Lackof support of the tongue    musculature

                                Airwayobstruction

*             Respiratorydifficulty in supine position noted from birth

*             Thepalatal cleft is often U0shaped and wider than isolated CP