An Introduction to Orthodontics - 85-96

109°.

To compensate for the effect of an aberrant nasion position on ANB.

An approximation of the cranial base.

Little change occurs in the anterior cranial base after 7 years.

Variations in the position of nasion affect angles SNA and SNB, thus influencing their relationship in ANB.

1. The cranial base (line SN) is a reliable basis for comparison; 2) Points A and B represent maxillary and mandibular basal bone.

It is only a guideline for good facial aesthetics and not an indicator of stability.

To identify the component parts of a malocclusion and probable aetiological factors.

100°.

It serves as a treatment goal to ensure a good facial profile by positioning the lower incisor.

The tip of their lower incisor lay on or just in front of the A-pogonion line.

Subtract 0.5° from ANB for every degree that SNA is greater than 81°.

Add 0.5° to ANB for every degree that SNA is less than 81°.

To confirm treatment objectives have been met and to aid planning of retention.

93 ± 6°.

The risks associated with ionizing radiation make it no longer ethically possible to repeat such studies.

Lower incisor angle = 120° – MMPA.

Variability in the location of the Frankfort plane and the nasion.

To tilt the teeth to their normal angles, eliminating dento-alveolar compensation.

By periosteal remodeling on all surfaces.

The point of deepest concavity on the anterior surface of the mandibular symphysis, located on alveolar bone.

66%.

To estimate maxillary and mandibular positions using point A and pogonion.

81°.

Usually around 7–8%.

The radiograph for any abnormalities or pathology.

Approximately 1 mm.

A forward growth rotation.

The most anterior point on the frontonasal suture.

By comparing individual values with average values for their population.

The underlying skeletal pattern.

Anatomical structures known to be most stable.

It is crucial for planning changes to incisor position and for diagnosis prior to orthognathic surgery.

Evaluation of overall facial change relative to the cranial base.

A fixed point or reference line that does not change with time or growth.

The relationship of the maxilla and mandible with the occlusal plane.

ANB < 2°.

A mild Class II skeletal pattern.

Digitizing the digital lateral cephalometric image directly or using proprietary software for digitization and analysis.

Due to increasing awareness of the risk of damage to human tissue associated with ionizing radiation.

Proprietary acetate sheets.

By comparing values of sequential cephalograms.

To compare the position of the maxilla and mandible.

Inserting metal markers in the facial skeleton.

By using ear posts that fit into the patient’s external auditory meatus.

The Frankfort plane is a reference plane that must be horizontal to standardize the head position in the vertical axis.

The maxillary position.

The mandibular position.

To aid in diagnosis and treatment planning, especially for assessing the aetiology of malocclusion.

A clear radiograph and good knowledge of anatomy.

It allows for accurate entry, superimposition, and statistical comparison of multiple radiographs.

To enable comparison of cephalometric radiographs from one patient at different time points or from different individuals.

B. Holly Broadbent developed the cephalostat after the First World War.

Tooth movement and growth.

Due to uncertainty around the stability of the outcome or concerns about future unfavorable growth.

2°.

Digital radiographs eliminate processing faults and facilitate storage and transfer of images.

An altered posterior face height.

To patients with a skeletal discrepancy and/or where anteroposterior movement of the incisors is planned.

To monitor incisor inclinations and anchorage requirements in severe malocclusions.

The maxillary plane registered at the PNS.

Because projection errors are unavoidable in 2D representations of 3D structures.

The tip of the posterior nasal spine of the maxilla, often obscured by developing third molars.

It is one of the commonly used approaches in the UK for cephalometric analysis.

Angles SNA and SNB.

Differences are not in themselves an indication for treatment.

The point of deepest concavity on the anterior profile of the maxilla, also called the subspinale.

27° ± 4°.

28° ± 4°.

Lower anterior face height divided by total anterior face height, multiplied by 100.

To attenuate the beam and enhance the view of the soft tissues.

To check the alignment and positioning of teeth in patients with severe malocclusions.

It can be highly erroneous due to significant remodeling.

The most inferior point on the mandibular symphysis.

The line joining the porion and the orbitale, which is difficult to record accurately.

109 ± 6°.

As MMPA increases, lower incisors become more retroclined.

To allow for comparison of radiographs between patient groups or the same patient over time.

Dental and skeletal changes in the mandible.

These analyses should supplement clinical examination, and beauty is subjective.

A surgical approach.

Less than 6 μSv.

The most anterior point on the mandibular symphysis.

The line joining the ANS with the PNS, or a line parallel to the nasal floor if those points are difficult to determine.

By drawing a line perpendicular to the Frankfort plane, extending inferiorly from the nasion.

A line from the soft tissue chin to the upper lip used in soft tissue analysis.

It connects the soft tissue chin and the tip of the nose.

Evaluation of dental and skeletal changes in the maxilla.

To determine the type and amount of incisor movement required to correct overjet.

A 0.3 mm leaded propelling pencil.

± 0.5 mm for linear measurements and ± 0.5° for angular measurements.

Direct digital radiography using solid-state sensors and computed radiography using photostimulable phosphor plates.

Projection errors, difficulties in identifying landmarks, and measurement errors.

It should be considered an adjunct to clinical assessment.

The FOP is not easy to locate, affecting accuracy and reproducibility.

The relative position of the maxilla and mandible using incisors as indicators.

It is within the normal range.

The anterior contour of the zygomatic process.

Orthognathic treatment planning, particularly for patients with facial asymmetry.

8° ± 3°.

The analysis and interpretation of standardized radiographs of the facial bones.

A true lateral view.

To provide a baseline record prior to the placement of appliances.

The tip of the anterior process of the maxilla, situated at the lower margin of the nasal aperture.

The uppermost outermost point on the bony external auditory meatus.

The midpoint of the sella turcica.

With masking tape that does not leave a sticky residue.

Using a digitizer connected to a computer to record coordinates of cephalometric points.

By bisecting the angle formed by the tangents from the posterior border of the ramus and the inferior border of the mandible.

A line drawn between the cusp tips of the permanent molars and premolars, which can change orientation with growth and treatment.

1. Innermost surface of the cortical bone of the inferior border of the symphysis. 2. Anterior contour of the chin. 3. Outline of the inferior dental canal. 4. Crypt of the developing third permanent molars.

The most inferior anterior point on the margin of the orbit, typically determined using the left orbital margin.

The line connecting the midpoint of the sella turcica with the nasion, representing the cranial base.

Accurate identification is often difficult, especially in poor-quality radiographs.

The line joining gonion and menton, one of several definitions of the mandibular plane.