Orthognathic

• Orthognathic surgery


  The alignment of the jaws to normalize the relationship between the jaws themselves and the rest of the craniofacial complex
• The development of proper craniofacial form and function is a complex process
• Parts of the craniofacial complex

  • Spheno-occipital and sphenoethmoidal synchondroses
  • Nasal septum
• Majority of facial bone growth

  • In response to adjacent soft tissue and functional demands
  • Nasal, oral, and hypopharyngeal airway
  • Facial muscles
  • Muscles of mastication
• Normal growth of the face

  • Downward and forward with lateral expansion
  • Maxilla and mandible grow by remodeling or differential apposition and resorption of bone, producing changes in three dimensions
• Alterations in the pattern of growth or rate may result in abnormal skeletal morphology of the face and malocclusion
• Causes of dentofacial deformities

  • Inherited tendencies
  • Prenatal problems
  • Systemic conditions during growth
  • Trauma
  • Environmental influences
• Treatment objectives of orthognathic surgery

  • Obtain functional occlusion with teeth in the most ideal position
  • Correct underlying skeletal disharmony
  • Obtain maximum esthetic results
  • Skeletal stability
• Management of patients with dentofacial deformities requires integration between orthodontics and surgery
• Assessment of orthognathic patients

  • General assessment
  • Facial assessment
  • Intraoral assessment
  • Radiographic evaluation
• Angle's classification


  • Class I skeletal: The maxillary base is in a normal anteroposterior relationship to the mandibular base
  • Class II skeletal: The mandibular base is posterior to the maxillary base
  • Class III skeletal: The mandibular base is anterior to the maxillary base
• Angle's classification is an inadequate system for describing dentofacial skeletal deformities
• Pre-surgical treatment phase


  • Periodontal considerations
  • Restorative considerations
  • Orthodontic considerations
• Decompensation of dentition


  Improving the angulation of teeth over underlying bone, after which skeletal problems are corrected
• Objectives of pre-surgical orthodontics

  • Decompensation of dentition
  • Alignment of arches
  • Coordinate arches
  • Leveling of arches
• Orthognathic surgery during growth

  Interceptive surgery to restrict unfavorable growth and minimize subsequent deformity
• Orthognathic surgery after growth cessation

  Definitive surgery
• Ideal orthognathic planning objectives

  • Determine final post-surgical dental occlusion
  • Demonstrate post-surgical soft tissue facial appearance
  • Determine magnitude of skeletal hard tissue movement necessary
• Model planning


  Surgical procedures performed on study models to determine direction and distance of surgical movement necessary
• 2D soft tissue profile prediction planning

  Use of computer technology to superimpose digital images of patient's profile over bone landmarks and manipulate bone structures to predict facial esthetic result
• 3D computerized surgical planning

  Use of surgical planning software to produce a computerized model of skeletal and occlusal abnormalities, plan osteotomies and skeletal movements, and visualize soft tissue changes in 3D
• Mandibular condyles are located on the medial aspect of the ramus, posterior to the coronoid process
• The mandible is the only movable bone in the face