What Is the Radney Analysis?
The Radney analysis is a focused incisor-positioning set. Rather than attempting a full skeletal work-up, it does one thing thoroughly: it describes the inclination and the anteroposterior position of both incisors against a single common reference — the N–A line. As implemented in BCeph it reports four measurements: U1–NA in degrees and millimetres, and L1–NA in degrees and millimetres.
The approach grows out of a clinical observation by Radney, later distilled into a simplified protocol by Creekmore (1997): the incisal edges of the lower incisors tend to fall on the N–A line across a wide range of skeletal patterns. Where population-average incisor norms — such as those from Steiner or Downs — adapt poorly to Class II and Class III jaws, referencing both incisors to one maxillary line yields a target that flexes with the patient's own dental compensation.
That single-reference design is the whole point. Because every value is measured to the same N–A line, the upper and lower incisor readings are directly comparable — you can see at a glance how the two incisors sit relative to each other and to the maxillary apical base, without mentally converting between two different reference planes.
A focused set, not a standalone diagnosis. Radney is an incisor analysis — it does not measure skeletal jaw relationship or the vertical pattern. It is designed to be read alongside a skeletal analysis such as Steiner or the Nagasaki set. In BCeph all of these share one tracing, so the incisor detail and the skeletal context appear together.
Why Reference Both Incisors to N–A?
The N–A line runs from Nasion to point A (subspinale) and represents the anterior limit of the maxillary apical base. Steiner uses it as the reference for the upper incisor — but references the lower incisor to N–B, the equivalent mandibular line. That convention describes each incisor relative to its own apical base.
Radney takes a different view. By measuring the lower incisor to N–A as well, it expresses both incisors relative to one fixed line. This has a practical advantage: the relative anteroposterior relationship between the upper and lower incisors becomes a simple subtraction on a shared scale, which is convenient when the clinical question is about the two incisors' positions with respect to each other and to the maxilla — for example when planning the target incisor relationship in a retraction case.
The trade-off. A shared reference makes the incisors directly comparable, but it means the lower-incisor value is not read against the mandible. To judge lower-incisor inclination over its own basal bone — the classic extraction-decision metric — pair Radney with IMPA from the Tweed triangle, which BCeph computes from the same landmarks.
The Simplified Radney Analysis and Dental Compensation
Cephalometric analyses have long been used to define the ideal anteroposterior (AP) position of the incisors, conventionally by relating the incisal edge to skeletal landmarks (Ellis & McNamara, 1986). The weakness of average-based norms is that they describe a typical face rather than the patient in the chair, and they translate awkwardly to skeletal Class II and Class III patterns.
The Simplified Radney Analysis, as described by Creekmore (1997), addresses this. It builds on Radney's observation that the lower incisal edges sit consistently on the N–A line irrespective of skeletal pattern. From that single anchor, the working targets are a lower incisor roughly on the N–A line (about 0.5 mm ± 2 mm) and an upper incisor about 5 mm ± 2 mm ahead of it.
The width of those ranges is deliberate — it is where dental compensation lives. To deliver ideal overjet, the U1–NA distance naturally shortens in Class II patterns and lengthens in Class III, mirroring the way the dentition camouflages an underlying skeletal imbalance. Casko & Shepherd (1984) documented exactly this adaptive compensation in untreated subjects with ideal occlusions — which is why a single fixed number serves incisor planning less well than a target that moves with the skeletal pattern.
Anchoring both incisors to one maxillary reference therefore supports individualised planning grounded in facial balance and natural compensation, and it is efficient: only one reference line is needed to evaluate planned incisor position.
Working guidelines. Plan the lower incisor on the N–A line (≈ ±1 mm), and the upper incisor just ahead of the N–A line to achieve ideal overjet. Expect a smaller U1–NA distance in a Class II pattern and a larger one in Class III.
The Four Radney Measurements
Two angular measurements describe inclination; two linear measurements describe position. The angle and the distance are complementary — the angle tells you how the incisor is tipped, the distance tells you how far forward its edge sits.
| Measurement | Definition | Norm | Clinical significance |
|---|---|---|---|
| U1–NA (°) | Angle of the upper incisor long axis to line N–A | 22° ± 2° | Upper-incisor inclination. High = proclination relative to N–A; low = retroclination. |
| U1–NA (mm) | Perpendicular distance from the upper incisor tip to line N–A | 5 mm ± 2 mm | Upper-incisor protrusion — the Creekmore target sits ~5 mm ahead of N–A for ideal overjet. Smaller in Class II, larger in Class III; high = more protrusive, low = more upright. |
| L1–NA (°) | Angle of the lower incisor long axis to line N–A | 22° ± 2° | Lower-incisor inclination relative to the maxillary reference. High = proclination; low = retroclination. |
| L1–NA (mm) | Perpendicular distance from the lower incisor tip to line N–A | 0.5 mm ± 2 mm | Lower-incisor position — Radney's key observation is that the L1 edge sits essentially on the N–A line across skeletal patterns. High = anterior to N–A; low = posterior. |
Reading incisor position
The angle-plus-distance pairing is what makes incisor analyses informative. Two patients can share the same U1–NA distance with very different angulations — one with a bodily-protruded but upright incisor, another with a well-positioned root but a flared crown. The combination distinguishes a tooth that needs bodily retraction from one that needs torque correction, and the same logic applies to the lower incisor on the N–A scale.
Incisor proclined and/or its edge anterior to N–A. Often a candidate for retraction if crowding or profile concerns warrant it.
Incisor inclination and position close to the N–A reference values. Preserve position; address other factors.
Incisor retroclined and/or its edge posterior to N–A. Further retraction risks compromising lip support — proceed with caution.
How the Radney Analysis Guides Treatment Planning
The extraction versus non-extraction decision
Incisor position is at the centre of the extraction decision, and the Radney set puts the relevant numbers on one scale. Protrusive incisors (high angle and distance) in a crowded arch suggest that extraction space could be used for beneficial retraction; incisors already at or behind the N–A reference argue against extraction, since further retraction would flatten the profile and reduce lip support.
Setting the incisor target
Because both incisors are expressed against N–A, the analysis makes it straightforward to specify a target incisor position and read progress toward it. The angular value guides the torque prescription; the linear value guides how much anteroposterior movement is needed. Recording both before and after treatment documents the incisor response on a single, comparable scale.
Pairing with a skeletal and vertical context
On its own, an incisor position is only meaningful against the skeletal and vertical pattern it sits within. The same proclined lower incisor is acceptable in a low-angle Class III compensation and problematic in a high-angle Class II. Read Radney together with a skeletal analysis and the mandibular plane angle to put the incisor numbers in context — all available in the same BCeph session.
Clinical Targets for Planned Incisor Position
Cephalometric numbers are the foundation of incisor planning, but they are not the whole picture — the soft tissue draped over the incisors ultimately decides the smile and profile. Reading the cephalometric target against a soft-tissue reference keeps the plan tethered to the face, and there is broad consensus on the AP position of the upper incisors relative to facial soft-tissue landmarks.
Andrews (2008) brought the forehead into the conversation, using the forehead's facial axis (the FFA point) as a reference and placing the upper incisors ahead of the FFA point and behind glabella. The idea advanced soft-tissue-driven planning, though its dependence on forehead morphology can be awkward chairside.
Subsequent work has converged on the glabellar vertical line (GVL) — a true vertical dropped from glabella — as a practical, reproducible clinical reference (Adams et al., 2013; Carruitero et al., 2019; He et al., 2019). Profiles in which the incisors sit on or just behind the GVL are consistently rated the most balanced and harmonious. Naini & Gill (2017) refine this further, aligning the upper incisors with a true vertical from soft-tissue nasion, glabella, or a point between the two, depending on the morphology of the naso-glabellar region.
Population differences matter: a somewhat more protrusive upper-incisor position is supported for Asian and Black patients (Cho et al., 2021; Gidaly et al., 2019). Used on a smiling profile photograph, the GVL offers a stable, repeatable guide for placing the upper incisor in harmony with the rest of the face — a clinical complement to the N–A-based cephalometric target.
Limitations and When to Supplement
Radney is intentionally narrow, so most cases will read it alongside other modules:
- No skeletal or vertical measurements. The set has no SNA/SNB/ANB and no mandibular plane angle. Pair it with Steiner or the Nagasaki set for the skeletal picture.
- Lower incisor not read to the mandible. Because L1 is referenced to N–A, judge lower-incisor inclination over basal bone with IMPA from the Tweed triangle.
- No soft-tissue value. Incisor retraction affects the lips; confirm the profile with the Holdaway or E-line analysis before committing to a retraction plan.
- AP targets versus angular norms. The published Radney/Creekmore method is fundamentally about incisal-edge AP position — the millimetre targets above; the angular U1–NA and L1–NA values are BCeph additions reported as working norms. Interpret borderline lower-incisor readings together with IMPA and a soft-tissue reference rather than in isolation.
BCeph runs the Radney set alongside Steiner, Tweed, the Nagasaki set, the ABO set and ten other modules from a single tracing — so the skeletal, vertical, and soft-tissue context is one click away.