Progressive chin deviation and open bite on one side

§Chief complaint

Chin has been moving to the left over 2 years; back teeth on the right no longer meet

§Medical & dental history

• 01Healthy
• 02Previous orthodontics aged 13 with a good result, now relapsing

§Clinical examination

• 01Chin deviated 7 mm to the left, elongated right side of the face
• 02Right posterior open bite with a cant of the lip line
• 03Mouth opening normal; no joint pain or noise

§Figures

§Differential diagnosis

§Final diagnosis

Active right condylar hyperplasia (hemimandibular elongation)

Progressive asymmetry beyond the normal growth period, with more than 10% higher uptake on the right condyle on SPECT bone scan, shows continued active growth.

§Investigations

• 01SPECT bone scan
• 02CBCT with 3D measurement
• 03Serial photographs and study models

§Radiology

• 01SPECT — 58% vs 42% condylar uptake right versus left
• 02CBCT — enlarged right condylar head and elongated neck

§Treatment plan

• 01High condylectomy (3-5 mm) to stop active growth
• 02Orthodontics followed by orthognathic correction of the remaining asymmetry

§Surgical procedure

• 01Preauricular approach with facial nerve protection; 4 mm of the condylar head removed and reshaped; disc repositioned

§Histopathology report

Thickened, hypercellular cartilage cap with active endochondral ossification. Consistent with condylar hyperplasia.

§Follow-up & outcome

• 01Month 3 — no further deviation
• 02Month 12 — growth stopped on photographs; orthognathic planning begun

Outcome: Asymmetry stopped progressing; final jaw surgery completed with symmetrical face.

§Discussion

• 01Operating on the jaws alone while the condyle is still active leads to relapse — stop the growth first.

§Clinical pearls / learning points

• 01A difference over 10% between condyles on SPECT indicates active growth.

§Viva questions

§MCQs

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