hemimandibular hypertrophy along with its variants was first described by obwegeser and makek as a developmental deformity of unknown etiology affecting the mandible unilaterally .
various studies have assumed lowered genetic control over the formation and development of bilateral structures of the face or environmental inuences and accidents during development to be the cause .
a 34-year - old male patient reported to the out - patient department with a complaint of asymmetric appearance of his face .
he had been involved in a road accident 15 years ago that had caused severe trauma to his chin .
there were no other contributory findings in his dental , medical , and family history . on clinical examination , marked facial asymmetry was observed in the lower region of the face with deviation of the chin to the left .
the mandibular body and ramus appeared longer and wider on the right side as compared to the left side [ figure 1a ] .
posterio - anterior view of the skull demonstrated elongation of the condyle on the right side .
height of the ramus and body of the mandible were also larger along with transverse canting of the occlusal plane on the right side [ figure 1b ] .
three - dimensional computed tomography ( ct ) image showed elongation and enlargement of condyle , ramus , and body of the mandible on the right side [ figure 1c ] .
scintigram demonstrated hot spots indicative of increased uptake of radioisotope in the condylar region on the right side [ figure 1d ] .
thus on the basis of clinical and radiographic features , diagnosis of hemimandibular hypertrophy - elongation hybrid variant of the right side was confirmed .
patient was referred to the oral and maxillofacial surgery department , where orthognathic surgery was done and both function and esthetics of the patient 's facial structure were restored [ figure 1e ] .
34-year - old male patient presenting with facial asymmetry due to hemimandibular hypertrophy hybrid variant .
( b ) x - ray posterio - anterior view of skull shows mandibular enlargement and transverse canting of occlusal plane on the right side ( white arrow ) .
( c ) three - dimensional computed tomography shows right sided hemimandibular hypertrophy along with bilateral crossbite .
( d ) scintigram demonstrates hot spot ( arrow ) in the condylar region , indicative of increased activity in the mandible.on the right side .
an 18-year - old female patient reported to the out - patient department with a complaint of gradually developing asymmetry of her face .
she first noticed asymmetry of her face after a trauma she suffered about 5 years earlier . since then the condition had gradually deteriorated and attained the present status .
no information relevant to the condition was elicited from past dental , medical , and family history . on extra - oral examination ,
marked facial asymmetry was observed in the lower face region with deviation of chin toward the left side .
on intra - oral examination , mandibular central incisor midline was found not to coincide with facial midline .
panoramic radiograph revealed elongation of condyle , condylar neck , ramus and body of mandible on the right side .
horizontal dimension of the mandibular body was also larger as compared to that on the left side .
the distance between the mandibular roots and the inferior alveolar nerve on the right side was more than that on the left side [ figure 2c ] .
further , ct demonstrated elongation and medial rotation of right lower border of the mandible [ figure 2d and e ] . on the basis of all these findings ,
case 2 . 18-year - old girl with asymmetry of the face due to hemimandibularr hypertrophy hybrid.variant .
( a ) photograph of the face shows enlargement of mandible on the right side .
( c ) panoramic radiograph demonstrates elongation ( arrow ) and increased distance between the mandibular molar roots and inferior alveolar nerve canal on the right side ( double - headed arrow ) .
( d ) three - dimensional computed tomography ( ct ) shows elongation and enlargement of the mandible on the right side ( arrow ) .
( e ) ct axial view reveals asymmetry due to increased growth of the mandible on the right side ( arrow ) .
a 34-year - old male patient reported to the out - patient department with a complaint of asymmetric appearance of his face .
he had been involved in a road accident 15 years ago that had caused severe trauma to his chin .
there were no other contributory findings in his dental , medical , and family history . on clinical examination , marked facial asymmetry was observed in the lower region of the face with deviation of the chin to the left .
the mandibular body and ramus appeared longer and wider on the right side as compared to the left side [ figure 1a ] .
posterio - anterior view of the skull demonstrated elongation of the condyle on the right side .
height of the ramus and body of the mandible were also larger along with transverse canting of the occlusal plane on the right side [ figure 1b ] .
three - dimensional computed tomography ( ct ) image showed elongation and enlargement of condyle , ramus , and body of the mandible on the right side [ figure 1c ] .
scintigram demonstrated hot spots indicative of increased uptake of radioisotope in the condylar region on the right side [ figure 1d ] .
thus on the basis of clinical and radiographic features , diagnosis of hemimandibular hypertrophy - elongation hybrid variant of the right side was confirmed .
patient was referred to the oral and maxillofacial surgery department , where orthognathic surgery was done and both function and esthetics of the patient 's facial structure were restored [ figure 1e ] .
34-year - old male patient presenting with facial asymmetry due to hemimandibular hypertrophy hybrid variant .
( b ) x - ray posterio - anterior view of skull shows mandibular enlargement and transverse canting of occlusal plane on the right side ( white arrow ) .
( c ) three - dimensional computed tomography shows right sided hemimandibular hypertrophy along with bilateral crossbite .
( d ) scintigram demonstrates hot spot ( arrow ) in the condylar region , indicative of increased activity in the mandible.on the right side .
an 18-year - old female patient reported to the out - patient department with a complaint of gradually developing asymmetry of her face .
she first noticed asymmetry of her face after a trauma she suffered about 5 years earlier . since then the condition had gradually deteriorated and attained the present status .
no information relevant to the condition was elicited from past dental , medical , and family history . on extra - oral examination , marked facial asymmetry was observed in the lower face region with deviation of chin toward the left side .
on intra - oral examination , mandibular central incisor midline was found not to coincide with facial midline .
panoramic radiograph revealed elongation of condyle , condylar neck , ramus and body of mandible on the right side .
horizontal dimension of the mandibular body was also larger as compared to that on the left side .
the distance between the mandibular roots and the inferior alveolar nerve on the right side was more than that on the left side [ figure 2c ] .
further , ct demonstrated elongation and medial rotation of right lower border of the mandible [ figure 2d and e ] . on the basis of all these findings ,
( a ) photograph of the face shows enlargement of mandible on the right side .
( c ) panoramic radiograph demonstrates elongation ( arrow ) and increased distance between the mandibular molar roots and inferior alveolar nerve canal on the right side ( double - headed arrow ) .
( d ) three - dimensional computed tomography ( ct ) shows elongation and enlargement of the mandible on the right side ( arrow ) .
( e ) ct axial view reveals asymmetry due to increased growth of the mandible on the right side ( arrow ) .
obwegeser and makek classified condylar hyperplasia into two distinct types namely hemimandibular hypertrophy and hemimandibular elongation .
later , certain cases were seen with overlapping features and were categorized as a hybrid variant that showed a combination of hemimandibular hypertrophy and hemimandibular elongation .
hemimandibular elongation presents with a marked lateral displacement of the chin to the unaffected side and depressed commissure of lips on the affected side .
due to the asymmetric shift of underlying skeletal component to one side , occlusion gets de - arranged and clinically the mandibular dental centerline does not coincide with the midfacial line .
crossbite is observed on the unaffected side . since there is minimal or almost no discrepancy in the vertical component to the abnormal mandibular growth , open bites or transverse canting of the maxillary occlusal plane are not evident .
radiographically , there is elongation of the body of the mandible on the affected side .
differences between hemimandibular hypertrophy and hemimandibular elongation hemimandibular hypertrophy is a three - dimensional developmental enlargement of one side of the mandible including the condyle , condylar neck , ramus and body along with medial rotation .
the anomaly terminates exactly at the symphysis of the affected side and for this reason it is called hemimandibular hypertrophy .
it is distinct from hemimandibular elongation as the latter shows increase only in the horizontal component .
the etiology of hemimandibular hypertrophy is still under discussion . in the literature , genetic factors , circulatory problems , hormonal disturbances , traumatic lesions and arthrosis
there is an increase in the height of the affected side , giving the face a rotated appearance .
if the anomaly occurs before adolescent growth spurt then the maxilla follows the downward growth of the mandible and the teeth of the affected side are at a lower level , resulting in tilting of the occlusal plane in the transverse dimension .
if the maxilla is unable to follow the mandibular growth , an open bite becomes evident on the affected side .
panoramic radiograph shows that both the ascending ramus and condyle are elongated vertically along with thickening of the condylar neck .
the inferior border is bowed downward to a lower level compared to the unaffected side . due to elongation of the mandibular body , the distance between the molar roots and the mandibular canal is increased .
the thickness of the proliferative zone increases , the fibro - cartilaginous zone becomes hypertrophic , endochondreal bone formation occurs while the articular zone remains remarkably intact .
it can be used to determine the side that is affected , to demarcate between abnormal condylar growth and generalized mandibular growth , and finally to assess whether hyperplasia is still active or has become stable .
hybrid forms are the combination of unilateral hemimandibular hypertrophy and hemimandibular elongation and lead to marked facial asymmetry .
such cases present with both vertical elongation and lateral displacement , causing large degree of facial asymmetry ( seen in case 2 ) . due to overlapping features
, there are certain conditions such as hemifacial hypertrophy , hemifacial atrophy of opposite side , hyperactive condyle , monostotic fibrous dysplasia and segmental odontomaxillary dysplasia that need to be considered in differential diagnosis . in cases of hemifacial hypertrophy ,
entire half of the face is involved and the affected side shows enlarged teeth with rapid eruption of dentition .
other features include premature loss of primary teeth along with enlarged tongue and alveolar bone .
secondly , it is often associated with mental deficiency , skin abnormalities , compensatory scoliosis , wilms tumor and beckwith - weidemann syndrome .
monostotic fibrous dysplasia and segmental odontomaxillary dysplasia can be differentiated due to their unique radiographic features .
. acquired mandibular asymmetries involve pain , symptomatic changes , alterations in facial appearance and function with time .
other features include temporomandibular joint ( tmj ) crepitation , limited mandibular movements , severe crossbite and irregular condyle anatomy .
whereas , developmental changes do not involve pain , symptoms usually remain unchanged over time , no functional changes take place in the tmj , there may be limited protrusion without limiting mandibular rotation movements , a pronounced dental compensation in the asymmetric mandible may be present and the condyle remains pronounced and smooth , even in the presence of volumetric changes .
mandibular hypertrophy can be seen in proteus syndrome that is characterized by striking facial abnormalities , one of two subforms show unilateral condylar overgrowth causing progressive craniofacial asymmetry .
unilateral overgrowth of mandible can be clearly seen in female patients with klinefelter 's syndrome ( 47 , xxy ) .
finally , there are craniofacial malformations that do not affect the jaws directly , but lead to indirect , presumably compensatory , alterations of otherwise relatively normal condylar growth . for example , in cases of craniosynostoses such as crouzon , pfeiffer , and apert syndromes , unusual transverse mandibular growth may be regarded as an attempt at adapting to the impaired expansion of the cranial vault .
treatment for hemimandibular hypertrophy varies according to the age of the patient . in a growing child ,
prime goal is to obtain a proper functional occlusion , which is achieved by occlusal adjustments and maxillary expansion .
however , in an adult patient apart from orthodontic procedures , an additional muscle memory deprogramming with diagnostic splints is indicated to set the centric relation position .
patients suffering from hemimandibular hypertrophy often seek seclusion due to abnormal shape of the face and thus early diagnosis with computed tomography can aide in identifying the underlying malformations .
 hemimandibular hypertrophy and its variants result from unilateral excessive growth of the mandible and involve both the body and ramus of mandible . 
 this causes facial asymmetry and in turn accompanying psychological problems . in this report 
 we discuss use of imaging in diagnosis of these lesions and investigate the different variants . 