Table 1.

Functional staging of oral submucous fibrosis

Functional group	Clinical features
Group I	Very early case - mouth opening >36 mm
Group II	Early case - mouth opening 26-35 mm
Group III	Moderately advanced cases - mouth opening 15-25 mm
Group Iva	Advanced cases - mouth opening 2-15
Group IVb	Advanced cases with premalignant changes and malignant transformation