Lat Ceph Flashcards
Cephalometrics Definition
Standardised radiographic procedure for analysing the complexities of the live human head with a geometric measurement.
A cephalometric tracing comprises soft and hard tissue outlines and anatomic landmarks and points
Why Lat Ceph for Ortho
High % of severe malocclusions is associated with discrepancies in jaw relationships
Cephalometric analysis
- Collection of measurements derived from the cephalogram suitable for diagnosis and treatment planning/evaluation
- Has both angular and linear measurements
- Compared to norms
Standardisation for Lat Cephs
Distance from mid saggital plane to casette is the same for each patient
Indications for Lat Cephs
- Marked AP discrepancy: Class II, Class III
- Class I bimax protrusion
- Marked Vertical Discrepancy: AOB, Deep overbites
Cranial base landmarks
Sella - geometric centre of the sella turnica
Nasion - most anterior portion of the fronto-nasal suture
Basion - Most inferior tip of the clivus/Most anterior part of the foramen magnum
Porion - Most superior point of the external auditory meatus
Orbitale - Most inferior point of the lateral orbital margin
Maxillary landmarks
Anterior Nasal Spine - Most prominent point on the anterior maxilla in the mid-saggital plane
A-point - Deepest point in the concavity of the anterior maxilla in the mid saggital plane
Posterior Nasal Spine - Distal most point on the hard palate in the mid-saggital plane
Mandibular landmarks
Gonion - The midpoint of the mandibular angle between the mandibular ramus and corpus
Menton - The extreme inferior point of the mandibular symphysis
Pogonian - The extreme anterior point of the mandibular symphysis
B-point - Deepest point on the curvature of the mandibular alveolar process
Ceph Planes
Anterior cranial base - Sella Nasion (SN)
Frankfort Horizontal (FH) - Po-Or
Maxillary Plane (MxP) - ANS-PNS
Functional Occlusal Plane (FOP)
Mandibular Plane (MdP) - Go-Me
A-P Jaw Relationships
SNA - angle measuring the r/s of the maxilla to the cranial base
SNB - angle measuring the r/s of the mandible to the cranial base
ANB - angle measuring the relative position of the maxilla to the mandible (Skeletal base r/s) - WRT N point
Wits value - relative position of the maxilla to the mandible - WRT occlusal plane
Vertical Jaw Relationships
Frankfort-Mandibular plane angle (FMA)
Maxillary-Mandibular plane angle (MMA)
Posterior Facial Height: S-Go (60-66% of TFH)
Upper Anterior Facial Height: N-ANS
Lower Anterior Facial Height: ANS-Me (50-55% of TFH - should relate to MMA value)
Total Anterior Facial Height: N-Me
Dental Analysis
Inter-incisal angle: U1-L1
Profile Analysis
Rickett’s E-line: On soft tissue, from tip of nose to prominent point on chin
Used for checking lower lip protrustion - R/S of lower lip to E-line (Chinese is protruded)