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Postero anterior cephalometrics /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.for more details please visit
www.indiandentalacademy.com

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Postero anterior cephalometrics /certified fixed orthodontic courses by Indian dental academy

  1. 1. INDIAN DENTAL ACADEMY Leader in continuing Dental Education www.indiandentalacademy.com
  2. 2.  Introduction.  Technical Aspects.  Different Head Positions.  Exposure Conditions and Considerations.  Skull Anatomy : Frontal and Posterior View .  Radiographic Anatomy.  Cephalograph Tracing Procedure.  Structures Included in Postero-Anterior Cephalograph.  Postero-Anterior Cephalometric Landmarks.  Purpose Of Postero-Anterior Cephalometry.  Uses and Limitations of Postero-Anterior Cephalometry.  Bibliography. www.indiandentalacademy.com
  3. 3. Mal-occlusions and dento-facial deformities constitute three-Mal-occlusions and dento-facial deformities constitute three- dimensional conditions or pathologies. Orthodontic treatmentdimensional conditions or pathologies. Orthodontic treatment requires comprehensive three- dimensional diagnostic examinationrequires comprehensive three- dimensional diagnostic examination but assessment of postero-anterior and basilar cephalometric viewsbut assessment of postero-anterior and basilar cephalometric views are particularly important for dento-alveolar and facial asymmetries;are particularly important for dento-alveolar and facial asymmetries; dental and skeletal crossbites and functional mandibulardental and skeletal crossbites and functional mandibular displacements.displacements. With the advent of cephalometric radiography, postero-anteriorWith the advent of cephalometric radiography, postero-anterior cephalometric projections and relevant analyses constitute ancephalometric projections and relevant analyses constitute an important adjunct for qualitative and quantitative evaluation of theimportant adjunct for qualitative and quantitative evaluation of the dento-facial region.dento-facial region. www.indiandentalacademy.com
  4. 4. Equipment :: 1.1. Head-holder orHead-holder or Cephalostat.Cephalostat. 2.2. X-ray source.X-ray source. 3.3. Cassette holderCassette holder containing the film.containing the film. www.indiandentalacademy.com
  5. 5.  Patient positioning: Patient is positionedPatient is positioned upright facing theupright facing the film.film.  X-ray source: Connection betweenConnection between the X-ray source andthe X-ray source and cassette holdercassette holder containing the filmcontaining the film should be rigid.should be rigid. www.indiandentalacademy.com
  6. 6. Distance between X-ray source to patient: 5 feet ( 152.4cm)5 feet ( 152.4cm) For the postero-For the postero- anterior projection, theanterior projection, the distance is measureddistance is measured to the earpost axis.to the earpost axis. www.indiandentalacademy.com
  7. 7. Fixed Head Position: The patient is fixed in theThe patient is fixed in the head-holder with the helphead-holder with the help of two ear-rods, and theof two ear-rods, and the patient’s head rests onpatient’s head rests on the uppermost side of thethe uppermost side of the rods, which are insertedrods, which are inserted into the ear holes.into the ear holes. The Frankfort horizontalThe Frankfort horizontal plane is parallel to theplane is parallel to the floor in order to maintainfloor in order to maintain all vertical dimensions.all vertical dimensions. www.indiandentalacademy.com
  8. 8. Natural Head Position: It is a standardizedIt is a standardized orientation of head, whichorientation of head, which is assumed by focusing onis assumed by focusing on a distant point at eye levela distant point at eye level (Moorrees, 1985).(Moorrees, 1985). Reproducibility of theReproducibility of the natural head position isnatural head position is approx. 2approx. 200 , which supports, which supports its use in Cephalometryits use in Cephalometry.. ( Lundstrom and( Lundstrom and Lundstrom, 1992).Lundstrom, 1992). The ear rods are placedThe ear rods are placed directly in front of thedirectly in front of the tragus so that they lightlytragus so that they lightly contact the skin, thuscontact the skin, thus support the head bilaterallysupport the head bilaterally in transverse plane.in transverse plane. www.indiandentalacademy.com
  9. 9. Other techniques of head positioning: According to Chierici ( 1981): Patient’s head should be positioned with the tip of the nose andPatient’s head should be positioned with the tip of the nose and forehead lightly touching the cassette holder. This head position helpsforehead lightly touching the cassette holder. This head position helps evaluate craniofacial anomalies of upper face.evaluate craniofacial anomalies of upper face. According to Faber ( 1985): In cases of suspected significant mandibular displacement, theIn cases of suspected significant mandibular displacement, the postero-anterior cephalogram should be taken with the patient’spostero-anterior cephalogram should be taken with the patient’s mouth slightly opened.mouth slightly opened. This helps differentiate between functional mandibular displacementThis helps differentiate between functional mandibular displacement and dento-skeletal facial asymmetry.and dento-skeletal facial asymmetry. www.indiandentalacademy.com
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  11. 11. According toAccording to Manson- Hing, 1985:Manson- Hing, 1985: Film exposure dependsFilm exposure depends on certain factors like:on certain factors like: 1.1. Speed of the film.Speed of the film. 2.2. Speed of the screens.Speed of the screens. 3.3. Tube to film distance.Tube to film distance. 4.4. Size of patient’s head.Size of patient’s head. 5.5. Milli-amperage and kilo-voltage used in generating the X-Milli-amperage and kilo-voltage used in generating the X- ray beam.ray beam. 6.6. The film-exposure time .The film-exposure time . More exposure is necessary for postero-anterior cephalogamsMore exposure is necessary for postero-anterior cephalogams than for lateral viewsthan for lateral views (Enlow 1982) .(Enlow 1982) .www.indiandentalacademy.com
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  16. 16.  The tracing of postero-anterior cephalogram is carried out by placingThe tracing of postero-anterior cephalogram is carried out by placing the cephalogram in front of the examiner so that patient’s rightthe cephalogram in front of the examiner so that patient’s right should be on the examiner’s left.should be on the examiner’s left.  The tracing should include most of the important structures of theThe tracing should include most of the important structures of the upper, middle and lower anterior face and the posterior .upper, middle and lower anterior face and the posterior .  Assess and compare where the structures have been identified in theAssess and compare where the structures have been identified in the current lateral cephalogram of the same patient.current lateral cephalogram of the same patient. The tracing of Postero-anterior Cephalogram begins with the mid-lineThe tracing of Postero-anterior Cephalogram begins with the mid-line structures seen in the lateral cephalogram and should include thestructures seen in the lateral cephalogram and should include the occipital, parietal , frontal and nasal bones , the maxilla, the sphenoidoccipital, parietal , frontal and nasal bones , the maxilla, the sphenoid bone and the symphysis of mandiblebone and the symphysis of mandible (Broadbent, 1975).(Broadbent, 1975). www.indiandentalacademy.com
  17. 17. 1. External peripheral cranial bone surfaces 5. Orbital outline & inferior surface of the orbital plate of the frontal bone 4. Nasal septum, crista galli, and floor of the nose 6. Oblique line formed by the external surface of the greater wing of the sphenoid bone in the area of the temporal fossa 7. Superior surface of the petrous portion of the temporal bone 2. Mastoid processess 3. Occipital condyles www.indiandentalacademy.com
  18. 18. 8. Lateral surface of the frontosphenoid process of the zygoma and the zygomatic arch, including the key ridge 9. Cross section of the zygomatic arch 10. Infratemporal surface of the maxilla in the area of the tuberosity 11. Body and rami, coronoid process and condyles of the mandible 12. As many dental units as possible www.indiandentalacademy.com
  19. 19.  Ag- antegonion- the highest point in the antegonial notch  Ans- anterior nasal spine  Cd- condylar- the most superior point of the condylar head  Cor- coronoid- the most superior point of the coronoid process  Iif- incision inferior frontale- the midpoint between the mandibular central incisors at the level of the incisal edges  Isf- incision superior frontale- the midpoint between th maxillary central incisors at the level of incisal edgeswww.indiandentalacademy.com
  20. 20.  lpa- lateral piriform aperture- the most lateral aspect of the piriform aperture  Lo- latero orbitale- the intersection of the lateral orbital contour with the innominate line  M- mandibular midpoint- located by projecting the mental spine on the lower mandibular border, perpendicular to the line ag-ag  Lm- mandibular molar- the most prominent point on the buccal surace of the mandibular molar  Um- maxillary molar- the most prominent point on the buccal surace of the maxillary molar  Ma- mastoid- the lowest point of the mastoid process  Mx- maxillare- the intersection of the lateral contour of the maxillary alveolar process and the lower contour of the maxillozygomatic process of the maxilla www.indiandentalacademy.com
  21. 21.  Mo- medioorbitale- the midpoint on the medial orbital margin that is closest to the median plane  Mf- mental foramen- the centre of the mental foramen  Om- orbital midpoint- the projection on the line lo-lo of the top of the nasal septum at the base of the crista galli  Za- point zygomatic arch- point at the most lateral border of the centre of the zygomatic arch  Tns- top nasal septum- the highest point on the superior aspect of the nasal septum  Mzmf- zygomaticofrontal medial suture point  Lzmf- zygomaticofrontal lateral suture point www.indiandentalacademy.com
  22. 22. The postero-anterior cephalometry is useful as a diagnosticThe postero-anterior cephalometry is useful as a diagnostic tool. It serves to provide:tool. It serves to provide: Gross Inspection:Gross Inspection: It provides information about morphology, shapeIt provides information about morphology, shape and size of the skull, bone density, suture morphology.and size of the skull, bone density, suture morphology. It may help to detect pathology of hard and soft tissuesIt may help to detect pathology of hard and soft tissues Description and Comparison:Description and Comparison: Postero-anterior cephalograms of twoPostero-anterior cephalograms of two persons can be compared to describe the skull .persons can be compared to describe the skull . Diagnosis:Diagnosis: It analyses the nature and origin of the problem,It analyses the nature and origin of the problem, thereby, providing the possibility of quantification andthereby, providing the possibility of quantification and classification.classification. www.indiandentalacademy.com
  23. 23.  Treatment Planning:Treatment Planning: The diagnostic information obtained helps to decideThe diagnostic information obtained helps to decide comprehensive and precise treatment plan .comprehensive and precise treatment plan .  Growth assessment and evaluation of treatment results: Postero-anterior cephalograms of a patient are taken at variousPostero-anterior cephalograms of a patient are taken at various time intervals and are compared to each preceeding one .time intervals and are compared to each preceeding one . The superimpositions are made on the external peripheral cranialThe superimpositions are made on the external peripheral cranial bone outline or on any of the reference horizontal planes.bone outline or on any of the reference horizontal planes. Interpretation of characteristics and relationships of variousInterpretation of characteristics and relationships of various craniofacial structures can also assess growth .craniofacial structures can also assess growth . www.indiandentalacademy.com
  24. 24. Aims: They evaluate craniofacial skeleton by means of linear absoluteThey evaluate craniofacial skeleton by means of linear absolute measurements of:measurements of:  Width or height.Width or height.  AnglesAngles  Ratios.Ratios.  Volumetric Comparison.Volumetric Comparison. www.indiandentalacademy.com
  25. 25. Uses:  Different structures of cranio-facial complex can also be analysedDifferent structures of cranio-facial complex can also be analysed using qualitative methods.using qualitative methods.  A postero-anterior cephalogram evaluates the verical, transverse andA postero-anterior cephalogram evaluates the verical, transverse and sagittal dimensions of different structures.sagittal dimensions of different structures.  Different structures can be evaluated w.r.t their vertical dimension,Different structures can be evaluated w.r.t their vertical dimension, position and proportionality.position and proportionality.  Vertical asymmetry can be easily detected by connecting bilateralVertical asymmetry can be easily detected by connecting bilateral structures, drawing transverse planes, and by observing their relativestructures, drawing transverse planes, and by observing their relative orientationorientation.( Sollar, 1947; Proffit,1991)..( Sollar, 1947; Proffit,1991).  The use of ratios in postero-anterior cephalogram can help compareThe use of ratios in postero-anterior cephalogram can help compare different persons or groups whose radiographs have been taken withdifferent persons or groups whose radiographs have been taken with uncontrolled enlargement of different structures of skull on X-rayuncontrolled enlargement of different structures of skull on X-ray filmfilm ( Athanasiou et al, 1992).( Athanasiou et al, 1992).www.indiandentalacademy.com
  26. 26. Limitations:  Precise linear measurements on postero-anterior cephalograms mayPrecise linear measurements on postero-anterior cephalograms may be misleading. eg. The apparent distance will be affected by a tilt ofbe misleading. eg. The apparent distance will be affected by a tilt of the head in the head holder.the head in the head holder.  Angular measurements can also be influenced in an uncontrolledAngular measurements can also be influenced in an uncontrolled manner.manner.  Diagnostic interpretation of ratios for clinical applications inDiagnostic interpretation of ratios for clinical applications in individual cases is difficult.individual cases is difficult. www.indiandentalacademy.com
  27. 27.  Athanasios E Athanasiou and Aart JW Van der Meij :Athanasios E Athanasiou and Aart JW Van der Meij : Orthodontic Cephalometry , Mosby-Wolfe Publications,1997 , 3Orthodontic Cephalometry , Mosby-Wolfe Publications,1997 , 3rdrd edn. , 141-161.edn. , 141-161. www.indiandentalacademy.com
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