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Facebow in orthodontics /certified fixed orthodontic courses by Indian dental academy


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The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.

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Facebow in orthodontics /certified fixed orthodontic courses by Indian dental academy

  1. 1. FACE BOW
  2. 2. INDIAN DENTAL ACADEMY Leader in continuing dental education m
  3. 3. DEFINITIONS A face bow is defined as a caliper like instrument used to record the spatial relationship of the maxillary arch to some anatomic reference point or points and then transfer this relationship to an articulator. It orients the dental cast in the same relationship to the opening axis of the articulator.
  4. 4. Orientation Jaw relation The orientation jaw relations are those that orient the mandible to the cranium in such a way that, when the mandible is kept in its most posterior position, the mandible can rotate in the sagittal plane around an imaginary transverse axis (hinge axis) passing through or near the condyles. This axis can be located or approximated by the use of a face bow.
  5. 5. Hinge axis It is an imaginary line passing through the centre of the condyles when the mandible rotates in the sagittal plane. This rotation is within 5 to 12º. There can be multiple axes of rotation. The axis of rotation that coincides with the centric relation is called the True hinge axis (THA).
  6. 6. THA should be accurately determined during treament with fixed prosthesis. this is not required for complete dentures because they are placed on displaceable tissues (realeff effect). Minor errors in hinge axis rotation during fabrication of complete dentures are overcome by this effect. Hence, arbitary face bows are sufficient to record orientation jaw relation for complete denture patients.
  7. 7. The components of a face bow are:  U-shaped frame  Condylar rods or earpiece.  Bite fork  Locking device  Third reference point.
  8. 8. U-shaped frame It forms the main frame of the face bow. All other components are attached to this frame. It extends from the region of TMJ on one side to the other side without contacting the face.
  9. 9. Condylar rods Two small metallic rods on either side of the free end of the U shaped frame that contact the skin over the TMJ. They are used to locate the hinge axis and transfer it to the articulator. Some face bows have ear piece that fit into the external auditory meatus instead of condylar rods.
  10. 10. Bite fork “U” shaped plate, which is attached to the occlusal rims, while recording the orientation relation. It is attached to the frame with the help of a rod called the stem.
  11. 11. Locking device. This part of the face bow helps to fix the bite fork to the U-shaped frame firmly after recording the orientation jaw relation.
  12. 12. Third reference point It is used to orient the face bow assembly to a anatomical reference point on the face along with the two condylar reference points. It varies in the different face bows, example orbital pointer-orbitale, Nose piece – Nasion etc.
  13. 13. Classification of face bows 1. Arbitary a. Fascia Type. b. Ear piece type 2. Kinematic
  14. 14. Arbitary face bow  The hinge axis is approximately located in this type of face bow.  It is commonly used for complete denture construction.  This type of face bows generally locate the true Hinge axis within a range of 5 mm. As the located hinge axis is arbitary, occclusal discrepancies produced in the dentures should be corrected by minor occlusal adjustments during insertion. 
  15. 15.  In the Fascia type, the hinge axis is located 13 mm anterior to the external auditory meatus on the cantho-tragal line.  In the Ear piece type, the posterior reference points are the external auditory meatus itself. The discrepancies of distance between the external auditory meatus and the hinge axis is compensated in the articulator by the manufacturer.
  16. 16. Kinematic face bow It is used to locate the true terminal hinge axis of the TMJ and transfer this record to the articulator when mounting the maxillary cast. The fork of the kinematic face bow is attached to the mandibular occlusal rim. Then as the patient retrudes the mandible and opens and closes the jaws, the dentist observes the movement of the sharp points of the condyle rods. When the points of the condyle rods rotate only and do not translate, it is located as the terminal hinge axis.
  17. 17. Value of the face bow Failure to use a face bow can lead to errors in occlusion of the dentures if cusp teeth are used. The face bow allows a more accurate arc of closure on the articulator.
  18. 18. Facebow record
  19. 19. Facebow transfer
  20. 20. Thank you Leader in continuing dental education