Cephalometric Analysis.pdf

Cephalometric Analysis Diagnosis and treatment planing: Lateral Cephalogram provides information about: Craniofacial skeleton Soft tissue pro le Dentition Pharynx Cervical vertebrae Uses of the Cephalometric Radiograph analysis: Pre-treatment Diagnosis Progress of treatment and Growt...

Cephalometric Analysis Diagnosis and treatment planing: Lateral Cephalogram provides information about: Craniofacial skeleton Soft tissue pro le Dentition Pharynx Cervical vertebrae Uses of the Cephalometric Radiograph analysis: Pre-treatment Diagnosis Progress of treatment and Growth analysis Post-treatment results Measurements and analysis can be done by: Hand tracing or Special computer program like Dolphin software Cephalostat Anatomical landmarks has to be: Valid: Extents to which measurement represents structure under consideration Reproducible: Closeness of repeated measurements of the same structure Best (easily seen): for example, Sella Worst (hard to be seen ): for example, Lower incisor apex and Gonion 1 of 4 fi Nasion (N): The most anterior point of the frontonasal suture in the median plane. Sella (S): The midpoint of the pituitary fossa (sella turcica) in the median plane. Located in Sphenoid bone. Point A : The point at the deepest midline concavity on the maxilla between the anterior nasal spine and the prosthion. Point B : The point at the deepest midline concavity on the mandibular symphysis between infradentale and pogonion. Palatal Plane (PP) - ANS: Anterior nasal spine - PNS: Posterior nasal spine Pogonion (Pog): The most anterior point of the bony chin. Gnathion (Gn):The most anteroinferior point on the symphysis of the chin Menton (Me): The most inferior midline point on the mandibular symphysis Gonion (Go): The intersection of the ramus plane and the mandibular plane. Porion (P) : The superior point of the external auditory meatus. Located in the temporal bone. Orbitale (Or): The lowest point in the inferior margin of the orbit, midpoint between right and left. Requirements for good Cephalogram analysis: Natural head position Millimeter ruler Patient biting in Centric occlusion (CO) 2 of 4  5 Reference Lines - Sella nasion line - Frankfort line (Horizontal line between the orbit and the portion) - From the ANS to the PNS line - Mandibular line: Go to Gn - Occlusal plane: we take it from the molars and the premolars. No need for the anteriors In the tracing: Is the malocclusion Skeletal or Dental? - Normal ANB = (0-2 degrees) - we have to nd the SNA and SNB to get the ANB - If the ANB is from 0-2 then the patient has no skeletal problem - If the ANB more than 2 then it is a class 2 skeletal - If ithe ANB is less than 0 then it is skeletal class 3 Then we have to see wether the mandible is advanced or the maxilla is advanced, which jaw to blame What is the Vertical relation of the malocclusion? The normal number is SNMP = 33 - if more than this number then it is an open bite What is the dental component of the malocclusion? Is there any natural compensation? Upper Incisor to SN = 103 Lower Incisor to MP = 91 Upper Incisor to NA Degrees = 22 Upper Incisor to NA Mm = 4 Lower Incisor to NB Mm = 4 Degrees = 25 From those numbers we have to decide wether it is Proclination or reclenation. Just consider the following: Cephalometric radiograph is a 2-dimensional of 3-dimensional objects The amount of error in the identi cation of landmarks The variation of the Human face 3 of 4 fi fi Monitoring growth by superimposition of two cephalometric radiographs: Overall —> S-N line over Sella Mandible Follicle of 3rd molars Inner border of symphysis Inferior dental canal Anterior chin point. Maxilla —> Root of zygomatic arch Example: - -5. Is a class 3, then we check that anb and SNB is more therefore due to prognathic - SN: within nomral - MP: - U1 SN: shows proclination - L1 MP: show retroclined Class 3 mandibular prognathism 4 of 4