Podcast
Questions and Answers
What is the cephalometric landmark defined as?
Which landmark is defined as the center of Sella turcica?
What is the PNS landmark in cephalometrics?
Which landmark is described as the anteroinferior point on the contour of the bony chin symphysis?
Signup and view all the answers
What does ANS stand for in cephalometrics?
Signup and view all the answers
Which landmark represents the most inferior point on the symphysis of the mandible in the median plane?
Signup and view all the answers
What is the angle of facial convexity defined as?
Signup and view all the answers
In which gender is a more convex soft tissue profile considered esthetically pleasing?
Signup and view all the answers
What is the purpose of the Ricketts E-line in cephalometric analysis?
Signup and view all the answers
Which cephalometric plane connects the midpoint of sella turcica with nasion?
Signup and view all the answers
What landmarks does the Frankfort Plane pass through?
Signup and view all the answers
Which line represents the cranial base in cephalometric analysis?
Signup and view all the answers
What is the intersection of the lateral radiographic image of the posterior border of the ramus with the base of the occipital bone called?
Signup and view all the answers
Which point is located at the most superior point of the external auditory meatus?
Signup and view all the answers
What is the most inferoposterior point on the anterior margin of the foramen magnum called?
Signup and view all the answers
Which landmark is described as the most prominent midline point in the midsagittal plane between the eyebrows?
Signup and view all the answers
Where is the point where the columella merges with the upper lip in the midsagittal plane located?
Signup and view all the answers
What comprises the lower two-thirds in an ideal lower third facial structure?
Signup and view all the answers
Study Notes
Cephalometrics in Ortho
- Replacing 2D with 3D CBCT, allowing for a multi-aspect view (x, y, z format) of the entire craniofacial structure with one radiograph.
Cephalometric Landmarks and Planes
- Cephalometric landmarks are points used in precise evaluation of 2D measurements like length, width, or height.
- Global acceptance of cephalometric landmark definitions and associated linear and angular measurements is essential for standardized classification and discussion of growth, development, and treatment outcomes.
Hard Tissue Landmarks
- Sella point (S): Center of Sella turcica.
- Orbitale (Or): The lowest point on the inferior margin of the orbit.
- ANS (Anterior Nasal Spine): Sharp median process formed by the forward prolongation of the two maxillae at the lower margin of the anterior aperture of the nose.
- PNS (Posterior nasal spine): The most posterior point at the sagittal plane on the bony hard palate.
- A point: The most posterior point on the curve of the maxilla between the anterior nasal spine and supradentale.
- B point: The deepest point of the anterior alveolar bone recess of the mandible.
- Pogonion (Pog): The most anterior part of the chin.
- Gnathion (Gn): Most anteroinferior point on the contour of the bony chin symphysis.
- Menton (Me): Most inferior point on the symphysis of the mandible in the median plane.
Soft Tissue Landmarks
- Convexity: The intersection of soft tissue nasion–subnasale line (N ′ Sn) and the subnasale–soft tissue pogonion line (SnPg ′).
- The angle of facial convexity: Angle formed between the glabellasubnasale line (GSn) intersecting with the SnPg ′ line.
- In females, a more convex profile is considered esthetically pleasing, while straighter profiles are generally preferred for males.
Ricketts E-Line
- Ricketts E-line (esthetic plane): Drawn from the tip of the nose to Pg ′.
- Ideally, the upper lip is about 4 mm behind this reference line, while the lower lip lies about 2 mm behind it.
Cephalometric Planes
- Horizontal planes:
- SN Plane: Connecting the midpoint of sella turcica with nasion, representing the cranial base.
- Frankfort Horizontal Plane: Passing through porion and orbitale.
- Maxillary Plane: Passing through anterior nasal spine and posterior nasal spine.
- Occlusal Plane: Passing through occlusal surface of 1st molars and incisal edge.
- Mandibular Plane: Passing through gnathion, pogonion, and menton.
- Other points:
- Gonion (Go): Midpoint of the angle of the mandible.
- Articulare (Ar): Intersection of the lateral radiographic image of the posterior border of the ramus with the base of the occipital bone.
- Basion (Ba): The most inferoposterior point on the anterior margin of the foramen magnum.
- Glabella: The height of curvature of the bone overlying the frontal sinus.
- Porion (Po): A point located at the most superior point of the external auditory meatus.
- Pterygoid Point (Pt): Intersection of the inferior border of the foramen rotundum with the posterior wall of the pterygomaxillary fissure.
Soft Tissue Landmarks
- Trichion (Tri): Hairline.
- Soft tissue Glabella: The most prominent midline point in the midsagittal plane between the eyebrows.
- Subnasale (Sn): The point at which the columella (nasal septum) merges with the upper lip in the midsagittal plane.
- Stomion (St): The contact point between the upper and lower lip at the mouth slit.
- Soft tissue menton (Me’): The most inferior point on the soft tissue chin.
- In an ideal lower third, subnasale to stomion (St) comprises the upper third, while menton to stomion (or the top of the lower lip) make up the lower two-thirds.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Learn about the advancements in cephalometrics with the use of 3D CBCT technology in orthodontics. Explore how 3D radiographs can replace multiple 2D radiographs and provide a comprehensive view of the craniofacial structure from multiple angles. Understand cephalometric landmarks and planes used for precise evaluation of 2D measurements.
