Essential Diagnostic AIDS In Orthodontics

Essential Diagnostic AIDS In Orthodontics

• They are simple and do not require expensive equipments.
• Following are the essential diagnostic aids:
  • Case history
  • Clinical examination
  • Study models
  • Certain radiographs (lOPA, Bitewing, Panoramic)
  • Facial photographs.

• Skeletal analysis.
• Dental analysis.
• Soft tissue analysis.

• SNA angle: The angle formed by the intersection of SN plane and a line joining nasion and point A. Indicates position of maxilla in relation to cranium.The mean value is 82°.Value increased in prognathic maxilla (Class 2). Value decreased in retrognathic maxilla (Class 3).
• SNB angle: Angle between SN plane and line joining nasion to point B.
  • This angle indicates the position of mandible to cranial base.
  • Average value is 80°.
  • Value increase in prognathic mandible (Class 3).
  • Value decreased in retrognathic mandible (Class 2).
• ANB angle: Angle between line joining point A to nasion and a line joining point B to nasion.
  • It indicates position of maxilla and mandible to each other.
  • Average value is 2 degree.
  • Increased value indicates class II skeletal malocclusion.
  • Decreased value indicates class III skeletal malocclusion.

“Common challenges in using essential diagnostic aids effectively”

• Mandibular plane angle: It is the angle between SN plane and mandibular plane.
  • Average value is 30°.
  • Indicates growth pattrn of individual.
  • Lower angle indicates horizontal growing pattrn of individual.
  • Increased angle indicates vertical growing pattrn of individual.
• Occlusal plane angle: The angle between the SN plane and occlusal plane.
  • Occlusal plane is line passing through the overlapping cusps of the fist premolar and fist molar.
  • It has a mean value of 14.5°.
  • It indicates the relation of occlusal plane to the cranium and face.
  • Also indicates growth pattrn in individual.

• Upper incisor is related to N-A line for determination of its position.
• Upper incisor to N-A (Angle):It is the angle formed by the intersection of long axis of the upper central incisor and the line joining nasion to point A. Mean value is 22°.
• An increase in angle indicates proclined upper incisors (class II malocclusion) and decrease in the angle is suggestive of retroclination.
• Upper incisors to N-A (Linear): It is a linear measurement between the labial surface of upper central incisor and the line joining nasion to point A. Mean value is 4 mm.
• It increases with proclined upper central incisor and decreases with retroclination.

• Lower incisor is related to N-A line for determination of its position.
• Lower Incisor to N-B (angle): The angle between the N-B plane and the long axis of the lower incisor. Mean value is 25°.
• Increased value indicates proclination of lower incisor while the decreased value indicates upright or retroclined lower incisor.
• Lower Incisor to NB (linear): Linear distance between the labial surface of lower central incisor and the line joining nasion to point B. Mean value is 4 mm.
• Increased value indicate proclined lower central incisor while decreased value indicates of retroclination.

• Angle formed between the long axis of the upper and lower central incisor.
• Mean value is 132°
• When upper and lower incisors are proclined angle is acute.
• When upper and lower incisors are retroclined angle is obtuse.
• These angulations help in detecting incisors with defective angulations.

• In well balanced faces, lip lie along the S line.
• Lips which are located anterior to S line are protrusive. Orthodontic treatment should be carried in order to reduce protrusion.

“Early warning signs of untreated issues detectable via diagnostic aids”