Key Cephalometric Values and Their Normal Ranges

Marcello M. | January 28, 2025

In orthodontics, cephalometric analysis is a cornerstone for assessing skeletal, dental, and soft tissue relationships. To ensure accurate diagnoses and effective treatment planning, understanding both the calculated values and their corresponding normal ranges is essential. Here is a detailed overview of the key cephalometric values, their significance, and their normative ranges.

Key Cephalometric Values and Their Normal Ranges

Below are the most commonly analyzed parameters in cephalometry, along with their normal values. These metrics provide insights into the skeletal structure, dental positioning, and soft tissue proportions of the face.

1. Skeletal Relationships

• SNA (Sella-Nasion-Point A): Normal value: 80° ± 2°
  Indicates the anteroposterior position of the maxilla relative to the cranial base.
• SNB (Sella-Nasion-Point B): Normal value: 78° ± 2°
  Reflects the anteroposterior position of the mandible relative to the cranial base.
• ANB (Point A-Point B): Normal value: 2° ± 2°
  Measures the relative position of the maxilla and mandible, crucial for determining skeletal Class I, II, or III relationships.
• SN Mx (SN-Maxillary Plane): Normal value: 8° ± 3°
  Assesses the inclination of the maxilla relative to the cranial base.

2. Functional Analysis

• Wits Appraisal:
  Boys: Normal value: +1 mm
  Girls: Normal value: 0 mm
  Indicates the relative position of the maxilla and mandible at the occlusal plane, a key parameter for diagnosing jaw discrepancies.

3. Vertical Dimensions

• FMA (Frankfort Mandibular Plane Angle): Normal value: 27° ± 5°
  Helps determine vertical growth patterns and facial divergence.
• MMPA (Maxillary-Mandibular Plane Angle): Normal value: 27° ± 5°
  Similar to FMA, it assesses the angular relationship of the jaws in the vertical plane.
• ArGoMe (Articulare-Gonion-Menton Angle): Normal value: 128° ± 6°
  Evaluates mandibular growth direction and morphology.

Dental Relationships

• UI Mx (Upper Incisor to Maxillary Plane): Normal value: 109° ± 9°
  Reflects the inclination of the upper incisors to the maxillary plane.
• LI Md (Lower Incisor to Mandibular Plane): Normal value: 93° ± 6°
  Assesses the inclination of the lower incisors to the mandibular plane.
• Interincisor Angle: Normal value: 133° ± 10°
  Measures the angulation between the upper and lower incisors, important for understanding occlusal relationships.
• LI to Apo (Lower Incisor to A-Po Line): Normal value: 1 mm ± 2 mm
  Indicates the anteroposterior position of the lower incisors relative to the facial profile.

Soft Tissue Parameters

• Upper Lip to E-Plane: Normal value: 4 mm
  Evaluates the relative position of the upper lip to the aesthetic E-plane.
• Lower Lip to E-Plane: Normal value: 2 mm
  Similar to the upper lip, it assesses the lower lip's position for facial esthetics.
• Nasolabial Angle: Normal value: 110° ± 10°
  Measures the angle formed by the upper lip and the columella, providing insights into facial esthetics.

Facial Proportions and Total Dimensions

• TAFH (Total Anterior Facial Height): Normal value: 119 mm
  Represents the total vertical height of the face.
• UAFH (Upper Anterior Facial Height): Normal value: 54 mm
  Measures the upper third of the anterior face.
• LAFH (Lower Anterior Facial Height): Normal value: 65 mm
  Indicates the lower third of the anterior face.
• %LAFH (Lower Anterior Facial Height Percentage): Normal value: 55% ± 2%
  The ratio of lower facial height to the total anterior facial height, important for evaluating vertical facial balance.

Clinical Implications

Understanding and correctly interpreting these cephalometric values enables orthodontists to:

• Diagnose skeletal discrepancies and dental malocclusions.
• Evaluate growth patterns and facial proportions.
• Plan individualized treatments based on precise measurements.
• Communicate findings effectively with patients and colleagues.

OrthoAnalyser incorporates automated tools to calculate these values accurately, compare them with normal ranges, and generate detailed reports. By streamlining the process, this platform empowers orthodontists to focus on clinical excellence while ensuring patient understanding and engagement.

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