Slavicek analysis describes occlusal and mandibular plane angles to Frankfort Po–Or, vertical S-Go/N-Me, and linear Co–Go and Co–Me on the lateral cephalogram. Rudolf Slavicek linked occlusion to gnathologic diagnosis without replacing functional TMJ tests. CephCalc calculates OP–FH and MP–FH after the clinician marks Porion and Orbitale. This is an FH-based guide, not a substitute for axiography.
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About the method
Slavicek's functional guide on the lateral cephalogram describes occlusal and mandibular plane angles to Frankfort Po–Or, vertical S-Go/N-Me, and linear surrogates Co–Go and Co–Me. Rudolf Slavicek linked occlusion to gnathologic diagnosis without replacing axiography or functional TMJ tests. OP–FH and MP–FH calculate after the clinician traces Porion and Orbitale. Occlusal plane ii–P6 sets the reference for angles to FH. In CephCalc the preset complements vertical schools Björk and Jarabak on the same image. Check image quality: soft-tissue contrast and landmark clarity affect repeatability on follow-up cephalograms. Read OP–FH with clinical occlusal plane assessment.
What the analysis focuses on
OP–FH, MP–FH, S-Go/N-Me, linear Co–Go and Co–Me, occlusal plane ii–P6.
When to use it clinically
Useful in gnathologic cases and assessing occlusal plane relative to FH on the lateral cephalogram. TMJ diagnosis and condylar trajectory remain with clinical exam and functional testing. For vertical, the preset is often combined with Björk or Jarabak. Error in Porion or Orbitale shifts OP–FH and MP–FH — note FH quality in the record. On case review, match the CephCalc table with profile photos, models, and TMJ exam: numbers without context are easy to misread.
ANB: ∠ ANB — difference in jaw positions: angle between B–N and A–N
SNA: ∠ SNA — angle between lines S–N and A–N (maxillary position relative to the cranial base)
SNB: ∠ SNB — angle between lines S–N and B–N (mandibular position)
Wits: Wits (mm) — distance between projections of A and B onto the occlusal plane ii–P6
OP–FH and MP–FH: measurements for training
Slavicek links the occlusal plane to FH and MP. Co–Go and Co–Me give linear context for ramus and body. Students benefit from drawing FH and OP on the tracing before reading angles in CephCalc.
FH = Po–Or
OP–FH — occlusion to FH
MP–FH — mandible to FH
S-Go/N-Me — vertical
Co–Go, Co–Me — length surrogates
Po, Or, and occlusal plane: errors
Porion and Orbitale define FH: Or error shifts OP–FH and MP–FH. The occlusal plane should reflect contacts on the film. With open mouth on the ceph, angles to FH are unreliable.
Check head tilt on the film
Do not shift Po toward Co
ii–P6 on representative teeth
Repeat FH the same way on serial films
Limits and related methods
Slavicek does not diagnose disc displacement. For airway add McNamara airways. CephCalc keeps Slavicek and Jarabak on one tracing.
Axiography — hinge axis
McNamara airways — pharynx
Holdaway — lip profile
CBCT — TMJ structures
Try it in practice — free
Try it in practice
Upload a lateral cephalogram to CephCalc, place the landmarks, and run the Slavicek analysis online — no software to install. Try it in practice free.
Ready-made method preset on your radiograph
Table of angular and linear measurements with race-specific reference norms (Caucasoid, East Asian, African)
Mark Porion, Orbitale, occlusal plane points ii–P6, Co, Go, Me, and S, N for vertical relations. CephCalc calculates OP–FH, MP–FH, and linear surrogates.
Does Slavicek on a cephalogram replace axiography?
No. Slavicek on the lateral ceph does not replace axiography or clinical TMJ diagnosis. It is a plane-orientation guide on the lateral projection.
How should a resident read OP–FH?
OP–FH describes occlusal plane inclination to FH; MP–FH describes the mandibular plane. Read them with S-Go/N-Me and clinical occlusion.
What norms does CephCalc use?
Reference norms for OP–FH and MP–FH appear in the CephCalc table by selected race and age profile after FH is traced.
What combines with Slavicek?
Combine with Björk or Jarabak for vertical relations and Steiner for sagittal relations. With TMJ pain rely on exam and CBCT when indicated.
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