MANDIBULAR RETROGNATHISM
Mandibular retrognathia refers to an abnormal posterior positioning of the mandibular in jaw relation to maxillary jaw.Mandibular retrognathism is more common than maxillary jaw.
EITIOLOGY
I.GENRAL FACTOR
1.HERETITY
2.CONGENITAL
3.ENVIRONMENT
a. pre-natal (trauma, maternal diet german maels maternal meyabolism)
b.post-natal (birth injury,cerebral palsy,tmj injury)
4.PRE DISPOSING METABOLIC CLIMATE AND DIEASES
– infectious dieases
5.DIEATERY PROBLEMS
6.ABNORMAL PRESSURE HABITS AND FUNCTIONAL ABERRATIONS
-milwakee braces used for correction of scoliosis
7. POSTUTRE
8.TRAUMA AND ACCIDENTS
II.LOCAL FACTOR
1.ANKYLOSIS
FACIAL FEATURES
1. Convex profile
2. Retruderd weak chin bird face deformity in extreme severe cases
3. Shorter upper lip, curled protrusive at rest
4. An everted lower lip, curved under the protrusive upper incisor with deep mento labial fold
5.Acute gonial angle
6.The lip strain will be evident if closure of mouth is attempted
DENTAL FEATURE
1.Class 2 molar malocclussion
2, Increased overjet
3. Lower anterior teeth may be tipped forward or crowded
4. Skeletal deep bite may be present
TREATMENT
A.GROWING PATIENT
MYOFUNCTONAL THERAPY
1. Activator
2.Bionater
3.Twin block
4.Herbest appliance
5.Jasper jumper
6.Headgear
B.NON GROWING PATIENT
1. Mild reterognathism
-orthodontic camouflage by extraction of some teeth
2.Severe reterognathism
-sagittal split osteotomy
-genioplasty
.
