Welcome back to our clinical cephalometric breakdown series at ceph.dentalorb.com. In our previous post, we looked at growth direction using the Bjork-Jarabak method. Today, we are breaking down a highly sophisticated European system built entirely around individual anatomic harmony: the Segner / Hasund Analysis.

Developed by Dr. Aas Hasund and later refined by Dr. Jörn Segner, this analysis moved orthodontics away from strict, static population averages. Instead, it recognizes that a person's "normal" jaw position depends entirely on their other facial features. It uses a floating system of structural harmony to give you an incredibly personalized diagnostic reading.

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Part 5: The Philosophy of Segner / Hasund Floating Norms

Traditional analyses say that an SNA angle of 82° is always ideal. However, Segner and Hasund demonstrated that if a patient has a long or short cranial base, or a steep skull base angle, an SNA of 85° or 79° might actually be perfectly harmonized for *their* specific face.

The Segner / Hasund method evaluates the face across three comprehensive dimensions: Sagittal jaw relations, Vertical skeletal planes, and a detailed Soft-tissue profile assessment. This comprehensive approach gives clinicians an unmatched view of structural balance and soft-tissue harmony.

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📐 Core Parameters & Clinical Interpretations

When you complete the landmark plotting sequence on Dental Orb, the system immediately calculates your patient's specialized values across these clinical sectors:

I. Sagittal Relations & Wits Appraisal

• SNA & SNB Angles [Norms: 82° / 80°]: Evaluates the forward or backward positioning of the upper and lower jaws relative to the skull base line.
• ANB Angle [Norm: 2°]: Shows the structural difference between the upper and lower jaw bases, establishing whether the patient fits a Skeletal Class I, II, or III category.
• Wits Appraisal [Norm: 0 mm]: Projects Points A and B perpendicularly onto the occlusal plane. This acts as a vital double-check to ensure that a steep skull base angle isn't masking a severe jaw discrepancy.

II. Vertical Plane Intersections

• NSBa Angle [Norm: 130°]: Measures the shape of the cranial base. This angle dictates how forward or backward the jaw joints sit relative to the face.
• MP - SN Plane [Norm: 32°] & MP - Palatal Plane [Norm: 25°]: These intersecting angles determine whether the jaws are opening vertically (Hyperdivergent) or closing horizontally (Hypodivergent).
• N:ANS / Total Facial Height [Norm: 45%]: Tracks the vertical proportion of the upper face compared to the lower face to ensure ideal aesthetic balance.

III. Soft Tissue & Holdaway Aesthetics

• Nasolabial Angle [Norm: 102°]: The angle formed at the base of the nose and the upper lip. An acute angle indicates a protruding upper lip, while an obtuse angle shows a flat or receded profile.
• H-Angle (Holdaway) [Norm: 10°]: Measures the profile's soft-tissue harmony by comparing the line from the chin to the upper lip against the bony facial plane. Higher values indicate prominent, protrusive lips.

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💻 How to Run Segner / Hasund Analysis on Ceph.DentalOrb.com

Our secure, offline-first web tool processes these multi-step geometric calculations directly inside your browser:

1. Step 1: Upload and Select Module
   Open ceph.dentalorb.com, upload your digital lateral cephalometric X-ray, and choose Segner / Hasund Analysis from the dropdown menu.


2. Step 2: Millimeter Calibration
   Because this analysis relies heavily on linear millimeter values (like the Wits Appraisal), click 测量 Calibrate and trace your 10mm spatial reference line carefully.


3. Step 3: Map the Skeletal & Soft-Tissue Landmarks
   Click Rx Analyze. Follow the visual prompts in the top black overlay box to click your structural points. This sequence includes cranial references (S, N, Ba), jaw limits (A, B, ANS, PNS, Go, Me, Pog), dental points, and crucial soft-tissue parameters (Nose tip, Subnasale, Lips, and Soft Chin).


4. Step 4: Generate Your Harmony Report
   As soon as the final soft-tissue point is clicked, the tool instantly displays your comprehensive diagnostic report in the sidebar. Variations outside normal ranges are automatically highlighted in red to guide your treatment planning. Click Print to save or compile a clean PDF chart.

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Help Keep Advanced Diagnostics Free: We are proud to provide this privacy-centric, web-based tracing engine completely free of charge to the global dental community. If this application helps your clinical or educational workflows, please support us by taking a brief moment to view the ads on our site. Your support covers our hosting and directly funds future AI automation updates!

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In Part 6 of our guide, we will step into advanced treatment planning and surgical predictability with the classic **Ricketts Bioprogressive Analysis**! If you have any questions, let us know in the comments below.

Welcome back to our clinical cephalometric breakdown series at ceph.dentalorb.com. In our previous post, we explored the visual ranges of Downs Analysis. Today, we are shifting our focus to a method that is indispensable for structural growth forecasting, pediatric interception, and surgical planning: the Bjork-Jarabak Growth Analysis.

Developed through the pioneering implant research of Dr. Arne Bjork and later refined for clinical practice by Dr. Joseph Jarabak, this method looks at the face as a dynamic polygon. It provides clinicians with a mathematical blueprint to determine whether a patient is growing vertically or horizontally, and how the individual parts of the jaw adapt to that growth.

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Part 4: What is Bjork-Jarabak Analysis?

The core of the Bjork-Jarabak method lies in its assessment of the Jarabak Polygon—a geometric shape formed by connecting five specific points on the skull and jaws: Sella (S), Nasion (N), Pogonion (Pog), Gonion (Go), and Articulare (Ar).

By studying the angles inside this polygon and comparing the height of the front of the face against the back of the face, the analysis accurately predicts the direction of mandibular rotation during growth. This makes it an incredibly powerful tool for predicting whether orthodontic treatments will face a favorable or challenging skeletal environment.

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📐 The Key Parameters & Diagnostic Values

When you map your lateral cephalogram on Dental Orb, the system immediately calculates these definitive growth metrics:

I. The Bjork Sum (Cranial Base & Jaw Angles)

Dr. Bjork demonstrated that by adding three specific internal angles of the facial polygon together, you get a highly predictable indicator of growth direction. The classic formula is: Saddle Angle + Articular Angle + Gonial Angle.

• The Clinical Norm Sum: 396° (±3°)
• Interpretation:
  • Increased Sum (Greater than 399°): Indicates a Clockwise (Vertical) growth pattern. The lower jaw tends to rotate backward and downward, which is associated with high-angle cases, weak chins, and open bite tendencies.
  • Decreased Sum (Less than 393°): Indicates a Counter-Clockwise (Horizontal) growth pattern. The lower jaw rotates forward and upward, resulting in strong chin projection, deep bites, and low-angle skeletal characteristics.

II. Individual Polygon Angles

• Saddle Angle (N-S-Ar) [Norm: 123°]: Evaluates the relationship of the anterior and posterior cranial base blocks. An increased angle often moves the TMJ posteriorly, pushing the lower jaw back.
• Articular Angle (S-Ar-Go) [Norm: 143°]: Reflects the relationship between the skull base and the mandibular ramus.
• Gonial Angle (Ar-Go-Gn) [Norm: 130°]: Measures the shape of the lower jaw itself. It is subdivided into an Upper Gonial Angle (indicates ramus inclination) and a Lower Gonial Angle (indicates body inclination). High values point to vertical growth patterns.

III. Facial Height Ratios (The Jarabak Quotient)

This is arguably the most famous part of the analysis. It compares the Posterior Facial Height (Sella to Gonion) against the Anterior Facial Height (Nasion to Menton).

• Jarabak Quotient Formula: (PFH / AFH) x 100
• Interpretation Ranges:
  • 54% to 58%: Hyperdivergent Pattern. Extreme vertical growth with minimal forward jaw rotation. Mechanics must avoid opening the bite further.
  • 59% to 63%: Neutral/Normal Pattern. Balanced vertical and horizontal skeletal growth.
  • 64% to 80%+: Hypodivergent Pattern. Strong horizontal growth with powerful forward jaw rotation, common in deep-bite configurations.

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💻 How to Run Bjork-Jarabak Analysis on Ceph.DentalOrb.com

Our interactive web platform allows you to map these critical growth paths smoothly:

1. Step 1: Upload and Module Setup
   Open ceph.dentalorb.com on your desktop or mobile browser. Upload your digital lateral cephalogram, and choose Bjork-Jarabak Analysis from the dropdown selector.


2. Step 2: Linear Calibration
   Click the 📏 Calibrate button. Draw your 10mm spatial reference path across your image's calibration grid to enable highly accurate millimeter output for facial heights.


3. Step 3: Point Mapping
   Click Rx Analyze. Follow the visual text cues on the screen overlay to plot the required skeletal landmarks sequentially: S, N, Ar, Pog, Go, Gn, and Me.


4. Step 4: View Your Growth Forecast
   As soon as Menton is clicked, the tool traces the Jarabak Polygon directly onto your X-ray image and outputs the full calculations in the sidebar. The system automatically highlights whether your patient falls into a clockwise, counter-clockwise, or neutral growth category. Click Print to generate a high-resolution PDF for your case documentation.

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Help Us Maintain These Diagnostic Resources: We are dedicated to providing advanced, secure, and privacy-respecting dental applications without subscription models. If this tool streamlines your diagnostic or educational workflows, please support us by taking a brief moment to view the advertisements displayed on this page. Your engagement ensures this resource stays free and open for practitioners worldwide!

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In Part 5 of our series, we will transition into comprehensive structural and soft-tissue harmony utilizing the balanced **Segner / Hasund Analysis**! If you have any clinical feedback, drop it in the comments below.

Welcome back to our comprehensive cephalometric series at ceph.dentalorb.com. In our previous posts, we broke down the classic systems of Steiner and Tweed. Today, we are exploring a highly objective system that introduced one of the most unique visual graphing methods in orthodontic history: Downs Analysis and its famous "Wiggle" diagram.

Developed by Dr. William B. Downs in 1948, this analysis was groundbreaking because it was derived entirely from living individuals with ideal, excellent occlusion. Instead of comparing a patient to an arbitrary single "norm," Downs created a range of normal values, allowing clinicians to visually track structural harmony at a glance.

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Part 3: What is Downs Analysis & "The Wiggle"?

Downs Analysis separates the facial structure into two distinct components: 5 skeletal parameters to assess the bony profile, and 5 dental parameters to assess the tooth positions.

To make interpretation easier, Dr. Downs mapped these 10 parameters onto a physical chart. The average normal values run vertically down the exact center of the chart. If a patient's measurements deviate, they are plotted to the left or right of the center line. Connecting these plotted points creates a jagged line—the deviation pattern. If the resulting line stays relatively straight down the center, the face is in perfect harmony. If it "wiggles" excessively to the sides, it instantly highlights where the structural imbalance lies.

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📐 The 10 Core Parameters & Clinical Ranges

When you map your digital cephalogram on Dental Orb, the software automatically computes these 10 key metrics:

I. Skeletal Parameters (Bony Profile)

• 1. Facial Angle (Norm: 87.8° / Range: 82° to 95°): Measured between the Frankfort Horizontal Plane and the Facial Plane (Nasion-Pogonion). It determines the degree of recession or protrusion of the chin.
  Interpretation: A low angle indicates a retruded, Class II chin profile; a high angle indicates a prominent, Class III chin profile.
• 2. Angle of Convexity (Norm: 0° / Range: -8.5° to 10°): Measured at the intersection of the Nasion-Point A line and the Point A-Pogonion line.
  Interpretation: A high positive value indicates a convex skeletal profile (Class II tendency), while a negative value indicates a concave profile (Class III tendency).
• 3. A-B Plane Angle (Norm: -4.6° / Range: -9° to 0°): Evaluates the relation of the anterior limits of the upper and lower jaw bases to each other, relative to the facial plane.
  Interpretation: Increasingly negative values indicate a Class II jaw relationship.
• 4. FMA / Mandibular Plane Angle (Norm: 21.9° / Range: 17° to 28°): Measures the steepness of the lower jaw base relative to the Frankfort Horizontal Plane.
  Interpretation: High values indicate vertical growth patterns; low values indicate horizontal, strong-jaw growth patterns.
• 5. Y-Axis / Growth Axis Angle (Norm: 59.4° / Range: 53° to 66°): Measured between the Frankfort Plane and the line from Sella to Gnathion.
  Interpretation: An increased angle shows a downward/vertical growth direction of the face; a decreased angle shows forward/horizontal growth.

II. Dental Parameters (Tooth Positions)

• 6. Cant of Occlusal Plane (Norm: 9.3° / Range: 1.5° to 14°): Measures the steepness of the biting surface relative to the Frankfort Horizontal Plane.
• 7. Interincisal Angle / IOPA (Norm: 135.4° / Range: 130° to 150°): The angle formed between the long axes of the upper and lower central incisors.
  Interpretation: A low angle indicates that both front teeth are tipped excessively forward (Bimaxillary Protrusion).
• 8. L1 to Occlusal Plane (Norm: 14.5° / Range: 3.5° to 20°): Measures the tilt of the lower incisor relative to the biting surface plane.
• 9. L1 to Mandibular Plane / IMPA (Norm: 91.4° / Range: 81.5° to 97°): Tracks the tilt of the lower front teeth relative to the lower border of the jaw.
• 10. U1 to L1 Protrusion / Distance (Norm: +2.7 mm / Range: -1 mm to 7 mm): Measures how far forward the upper incisor tip sits relative to the line connecting the lower incisor tip to the chin.

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💻 How to Run Downs Analysis on Ceph.DentalOrb.com

Our offline-first, highly secure web tool makes mapping these complex parameters simple:

1. Step 1: Upload and Select Module
   Go to ceph.dentalorb.com, upload your digital lateral cephalogram, and choose Downs Analysis from the dropdown selector.


2. Step 2: Calibrate
   Click the 📏 Calibrate button and plot your 10mm guide points to ensure precise linear millimeter readings.


3. Step 3: Sequential Landmark Plotting
   Click Rx Analyze. Follow the overlay box text at the top of the workspace to map the requested points: N, Pog, A, B, Or, Po, S, Gn, Go, Me, incisor tips/roots, and the first molar cusp contact point.


4. Step 4: Real-time Analysis Generation
   As soon as the last point is clicked, the system processes the trigonometry locally and delivers a categorized, color-coded report. You can instantly view where your patient falls within Downs' normal ranges. Click Print to generate a clean PDF chart for clinical compilation.

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Support Open-Access Dental Informatics: We believe powerful diagnostic tools should be universally accessible to dental students and practitioners. To help us maintain this web server and fund advanced modules without a subscription wall, please take a brief moment to view the advertisements displayed on this page. Your support ensures this resource stays online and free for all!

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In Part 4 of our series, we will transition into structural growth forecasting using the comprehensive **Bjork-Jarabak Analysis**! Leave your feedback or questions in the comment section below.

Welcome back to our multi-part series on mastering clinical cephalometrics online at ceph.dentalorb.com. In our previous post, we covered Steiner's classic method. Today, we are diving deep into an analysis that revolutionized orthodontic treatment planning by prioritizing mandibular incisor stability and facial aesthetics: Tweed's Diagnostic Triangle.

Developed by Dr. Charles H. Tweed in the 1940s and 1950s, this analysis is loved by clinicians worldwide for its simplicity, geometric elegance, and high clinical predictability, particularly when determining whether extraction is necessary to achieve structural stability.

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Part 2: Understanding Tweed's Diagnostic Triangle

Dr. Tweed observed that stable, healthy, and aesthetically pleasing orthodontic results were consistently tied to the position of the lower front teeth relative to the lower jaw bone. To quantify this, he constructed a geometric triangle using three specific planes:

1. Frankfort Horizontal Plane (FHP): Representing the true cranial base line (running from Porion to Orbitale).
2. Mandibular Plane (MP): Representing the lower border of the jaw (running from Gonion to Menton).
3. Long Axis of the Mandibular Central Incisor (L1): Representing the tilt of the lower front tooth.

The intersection of these three lines forms a triangle. Because the sum of all angles in any triangle must equal 180°, changing one angle mathematically alters the others. This geometric dependency is what makes Tweed's system incredibly reliable for diagnostic forecasting.

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📐 The Core Angles & Normal Values

When you complete the landmark plotting on the Dental Orb tool, your report will instantly calculate these three classic structural angles:

1. FMA (Frankfort-Mandibular Plane Angle)

• Clinical Norm: 25° (Acceptable Range: 20° to 30°)
• What it measures: The vertical inclination of the lower jaw base relative to the skull base. This angle dictates the patient's skeletal growth direction.
• Interpretation:
  • High FMA (Greater than 30°): Indicates a Hyperdivergent (Vertical) growth pattern. These patients typically exhibit long faces, weak chin projection, and a tendency toward open bites. Orthodontic treatment in high-angle cases must carefully manage vertical mechanics.
  • Low FMA (Less than 20°): Indicates a Hypodivergent (Horizontal) growth pattern. These patients have strong, square jaws, deep bites, and strong musculature.

2. IMPA (Incisor-Mandibular Plane Angle)

• Clinical Norm: 90° (Acceptable Range: 85° to 95°)
• What it measures: The structural angulation of the lower central incisor relative to the lower border of the jaw.
• Interpretation:
  • High IMPA (Greater than 95°): Indicates the lower incisors are Proclined (flared forward). This often happens naturally to compensate for a receded lower jaw, but excessive flaring reduces bone support and creates structural instability.
  • Low IMPA (Less than 85°): Indicates the lower incisors are Retroclined (uprighted or tipped backward).

3. FMIA (Frankfort-Mandibular Incisor Angle)

• Clinical Norm: 65°
• What it measures: The inclination of the lower incisor relative to the Frankfort Horizontal Plane. Dr. Tweed emphasized that achieving an FMIA close to 65° was the ultimate key to facial balance and long-term stability.
• Interpretation: If a patient has a high FMA (steep jaw), the lower incisor must be positioned more upright (lower IMPA) to maintain an ideal FMIA of 65° and safeguard the profile.

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💻 How to Run Tweed's Analysis on Ceph.DentalOrb.com

Our tool runs all geometric computations securely in your local browser. Here is how to complete a Tweed analysis step-by-step:

1. Step 1: Image Upload & Selection
   Open ceph.dentalorb.com, upload your digital lateral cephalogram, and select Tweed Analysis from the toolbar dropdown menu.


2. Step 2: Calibrate the Workspace
   Click 📏 Calibrate and trace your 10mm calibration reference marker to ensure any linear verification checks remain accurate.


3. Step 3: Plot the Triangle Landmarks
   Click Rx Analyze. Follow the clear overlay prompts to plot the following landmarks sequentially:
   • Porion (Po) & Orbitale (Or): Establishes the Frankfort Horizontal Plane.
   • Gonion (Go) & Menton (Me): Establishes the Mandibular Plane base.
   • L1 Tip & L1 Apex: Defines the long axis vector of the lower incisor.


4. Step 4: Analyze the Results
   Once the final point is set, the software instantly draws Tweed's triangle directly onto your digital X-ray and populates the data table in the sidebar. Green highlights indicate balanced relationships, while Red signals structural deviations requiring mechanical correction.

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Support Our Free Educational Tools: We are proud to provide this cloud-free, advanced cephalometric tracking software without charging licensing fees. To support our ongoing software updates and server maintenance, please take a brief moment to view the advertisements displayed on this page. Your engagement directly keeps this project free and accessible to the global dental community!

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In Part 3 of our guide, we will explore Downs Analysis and learn how to evaluate skeletal profiles using "The Wiggle" method! If you have any questions, let us know in the comments below.

Cephalometric radiography is one of our most powerful tools for diagnosing malocclusion, evaluating growth patterns, and planning orthodontic or surgical treatments. However, manually tracing hard-copy films with acetate paper and protractors is time-consuming and prone to human error.

To bridge this gap, we created the Free Online Cephalometric Analysis Tool at ceph.dentalorb.com. It is an offline-first, browser-based diagnostic assistant that allows you to instantly map structural landmarks and generate precise geometric reports.

In this multi-part series, we will break down each major analysis type available in our tool—starting with the gold standard: Steiner’s Analysis.

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Part 1: What is Steiner’s Cephalometric Analysis?

Developed by Dr. Cecil C. Steiner in the 1950s, this analysis is arguably the most widely taught method in orthodontics. Instead of relying on highly variable individual anatomical structures, Steiner utilized the stable Sella-Nasion (SN) line as his primary cranial reference plane.

The core philosophy of Steiner's method is simple: establish the underlying skeletal foundation first, analyze how the teeth fit onto that foundation, and finally assess how the soft tissue lips harmonize with the face.

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📐 The Core Measurements & Normal Values

Steiner’s analysis is divided into four main clinical categories. When you use the Dental Orb tool, your generated report will automatically compare your patient's values against these established clinical norms:

1. Skeletal Foundation (Anteroposterior Relation)

These angles determine whether the jaws are positioned correctly relative to the skull base.

• SNA Angle (Norm: 82°): Evaluates the anteroposterior (AP) position of the maxilla.
  Interpretation: Greater than 84° indicates Maxillary Prognathism (forward jaw); less than 80° indicates Maxillary Retrognathism (receded jaw).
• SNB Angle (Norm: 80°): Evaluates the AP position of the mandible.
  Interpretation: Greater than 82° indicates Mandibular Prognathism; less than 78° indicates Mandibular Retrognathism.
• ANB Angle (Norm: 2°): Calculated as SNA minus SNB, this reveals the structural relationship between the upper and lower jaws.
  Interpretation: Greater than 4° indicates a Skeletal Class II profile; less than 0° indicates a Skeletal Class III profile.

2. Skeletal Vertical Growth Pattern

• SN-MP Angle (Norm: 32°): The angle between the Sella-Nasion plane and the Mandibular Plane (Gonion-Gnathion).
  Interpretation: Greater than 36° represents a Hyperdivergent (High Angle) vertical growth pattern, often associated with long faces and open bites. Less than 28° represents a Hypodivergent (Low Angle) horizontal growth pattern, often seen in deep bites.

3. Dental Relations & Inclinations

These metrics track how much the front teeth have tipped or drifted to compensate for the underlying jaw structure.

• U1 to NA (Angle: 22° / Linear: 4 mm): Measures the tip and forward protrusion of the upper central incisor relative to the line connecting Nasion to Point A.
• L1 to NB (Angle: 25° / Linear: 4 mm): Measures the tip and protrusion of the lower central incisor relative to the Nasion-Point B line.
• Occlusal Plane to SN (Norm: 14°): Evaluates the steepness of the biting surface relative to the cranial base.

4. Aesthetic & Soft Tissue Harmony

• L1 to A-Pog (Norm: 1 mm): Measures the lower incisor tip to the structural line running from Point A to Pogonion. This is critical for predicting post-treatment dental stability.
• Upper & Lower Lip to S-Line (Norm: 0 mm): Steiner’s aesthetic line draws a tangent from the tip of the nose (Pronasale) to the soft-tissue chin (Soft Pogonion). Ideally, both lips should neatly touch this plane for optimal facial balance.

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💻 Step-by-Step: How to Run Steiner’s Analysis on Ceph.DentalOrb.com

Our tool handles all calculations locally in your web browser, ensuring complete patient data privacy. Follow these steps to generate a full report in under two minutes:

1. Step 1: Upload the Lateral Cephalogram
   Navigate to ceph.dentalorb.com and click the Choose File / Upload button on the toolbar. Select your patient's digital lateral cephalometric X-ray.


2. Step 2: Select your Analysis Module
   Use the dropdown selection menu in the toolbar and select Steiner's Analysis. The sidebar will automatically update to prepare for the specific landmarks required.


3. Step 3: Calibrate the Scale
   Click the 📏 Calibrate button. Find the millimeter ruler visible on your X-ray image or positioner template. Click the starting point, then click the 10mm mark. This trains the system's pixels-to-millimeter ratio for perfect linear accuracy.


4. Step 4: Plot the Anatomical Landmarks
   Click Rx Analyze. Look at the top black instruction overlay—it will tell you exactly which landmark to click next (e.g., "Tap: Sella (S)"). Follow the sequential prompts to accurately place your structural points (S, N, A, B, Pog, Gn, Go, incisor tips, and soft tissue contours).


5. Step 5: Review and Print the Diagnostic Report
   The moment your last soft-tissue landmark is placed, the tool will instantly exit analysis mode and display a neatly categorized structural report in your sidebar. Deviations from normal values are color-coded (Green for normal range, Red for critical skeletal/dental discrepancy). Click Print to generate a clean, printer-friendly PDF file to append to your patient's physical chart.

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Support Free Dental Software: To help us cover our high-performance web hosting, server maintenance, and future AI automation updates, we keep this tool completely free of charge. If you find this software helpful in your daily diagnostic workflows, please take a brief moment to view the ads displayed on our site. Your active support directly ensures that these diagnostic resources remain open and accessible to dental practitioners and students worldwide!

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Stay tuned for Part 2 of our guide, where we will dive deep into analyzing facial patterns using Tweed's Diagnostic Triangle!