Tuesday, June 4, 2013

Macrognathia Its Causes, Signs, Symptoms & Treatment


Macrognathia Its Causes, Signs, Symptoms & Treatment

Macrognathia- is a developmental disorder, in this condition, the patient  have an abnormally large jaw. Etymologically- Macro means large and Gnathic is related to the jaw. It is also called as megagnathia.


  • One of the major cause of macrognathia is hereditary.Pitutary Gigantism- increased production of growth hormone.
  • Paget's disease- overgrowth of cranium and maxillary bone.
  • Acromegaly- Continue production of growth hormone even after maturity.
  • Leantosis Ossea 

Signs & Symptoms, Clinical Features-

  • Lower jaw is larger than normal resulting in protruded chin.
  • Increased maxillary bone volume will result in gummy smile ie. more amount of gums become visible when patient smiles.
  • Prominent Chin button.
  • Prognathic mandible. 
  • Jaw angle is less steep.

Treatment of Megagnathia-  Requires combination of

  • Chin Reduction Surgery- Genioplasty
  • Osteotomy
  • Orthodontic Treatment

An opposite disorder of megagnathia is -

Micrognathia by verbal meaning it says Small Jaw. Any of the jaw - maxilla- the upper jaw or the mandible- lower jaw can be affected from it. By birth the child will have a small jaw or it may be found out later.


True micrognathia- The developmental deformity in which jaw does not grow o the full size. It can be congenital or acquired


Congenital- No specific cause is known, may be associated with other congenital problems like hear disease or Pierre- robin syndrome.


In acquired type of micrognathia patient gets it after the birth.Mouth breathing is one of the causes resulting in micrognathia of upper jaw.

Any abnormality in TMJ Temporomndibular joint - like ankylosis.

Non formation ( agenesis) of condyle also results in true mandibular micrognathia.

Signs and Symptoms-

Those patients who have micrognathia of maxilla may show retracted middle face due to deficiency of middle

face or premaxillary area.

In true mandibular micrognathia patient looks like having rerusion of chin, steep mandibular angle and deficient chin button.


Crowding and irregularly placed teeth this occurs due to lack of space for teeth to erupt and grow.

Occlusion may be different then normal


Jaw may be so small in infants that they need special nipples in order to feed the child.

Due to small jaw tongue is forced back into the oropharyngial space causing obstruction of airway space resulting in difficulty in breathing.


Depending upon the age of the patient and severity of the condition an orthodontic appliance or a surgery can be suggested.

Maxillary micrognathia can be corrected by advancing and bringing it forward by surgery. and orthodontic combined treatment.

Mandibular micrognathism can be corrected by mandibular advancment surgery.


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