57. Laterognatia. Prevention and treatment

Question 1

Perfect bilateral symmetry

Answer 1

• Exact correspondence in form from opposite sides of central axis
• Largely theoretical=>seldom exists in living organisms
• Asymmetry of face and dentition naturally occurring phenomenon
• Relative symmetry and midline coordination crucial for facial harmony and balance

Question 2

How symmetry defined in the context of craniofacial areas

Answer 2

• Correspondence of parts distributed around center or axis from two opposite sides
• Asymmetry in craniofacial areas=>differences in size or relationships of two sides of face=>
• Discrepancies in form of individual bones, malposition of one or more bones in craniofacial complex, or confined to soft tissues

Question 3

Areas of facial symmetry

Answer 3

• Nasal tip to midsagittal plane
• Maxillary dental midline to midsagittal plane
• Maxillary dental midline to mandibular dental midline
• Mandibular dental midline to mid-symphysis
• Mid-symphysis to midsagittal plane

Question 4

Classifications of midline in the context of craniofacial symmetry

Answer 4

• Dental Midline=>symmetry of dentition of maxilla and mandible
• Functional Midline=>functions of the stomatognathic system
• Skeletal Midline=>symmetry of the osseous structures of craniofacial region
• Soft Tissue Midline=>symmetry of the soft tissue of craniofacial region

Question 5

Phases of mandibular movement observed during closing maneuver from rest position to habitual occlusion

Answer 5

• Free Phase=>
• From postural rest position to point of initial contact or occlusal prematurity
• Articular Phase=>
• From initial contact position to centric occlusion or habitual occlusal position

Question 6

Laterodeviation

Answer 6

• When occlusal prematurity present
• Midline shift observed only during centric occlusion or intercuspidation=>
• While during postural rest position, midlines coincident and well-centered
• Mandible slides laterally from rest position into crossbite caused by tooth guidance after initial contact of free phase

Question 7

Laterognathia

Answer 7

• Midline shift present in both centric occlusion and postural rest position
• True asymmetry of mandible
• Functional appliances have poor prognosis, and surgical correction often required

Question 7

Etiological factors of laterognathia

Answer 7

• Genetic Factors=>multiple neurofibromatosis, hemifacial macrosomia, cleft lip and palate
• Dental Midline Shift=>midline diastema, asymmetrical exfoliation or retained deciduous teeth. early loss of primary teeth
• Functional Midline Shift=>neurological disturbances, tooth-to-tooth interrelationship issues (anterior/posterior crossbite, contracted maxillary arch)
• Skeletal Midline Shift=>genetic factors, local issues (trauma, ankylosis, nerve damage, loss of muscle function/tone, cysts, tumors), TMJ problems
• Soft Tissue Midline Shift=>neurological disturbances (e.g., cerebral palsy, hemifacial macrosomia), masseteric hypertrophy, trauma, scars, dermatomyositis

Question 8

Diagnostic aids used to identify and assess asymmetry of the face

Answer 8

• History
• Clinical Examination=>
• Frontal view
• Evaluation of=>
• Nasal tip to midsagittal plane
• Maxillary and mandibular dental midlines to midsagittal plane
• Mandibular dental midline to midsymphysis
• Midsymphysis to midsagittal plane
• Assessment of dental midline in different positions (mouth open, centric relation, initial contact, centric occlusion)
• Checking for missing and supernumerary teeth, tooth shape and size, arch form symmetry, frenal attachments
• Midline deviation test to distinguish between morphological discrepancy (laterognathia) and functional deviation (laterodeviation)
• Photographic Evaluation=>assess harmonic relationship among craniofacial structures, including muscles and adipose tissues
• Radiographic Evaluation=>
• OPG: Views TMJ, asymmetry of mandible, missing or supernumerary teeth, and pathological conditions like cysts and neoplasms
• Lateral Cephalogram, Intraoral Periapical (IOPA)