Table 1

Classification of stomatodeal structure duplications, adapted and modified from Chen and Noordhoff20

Type IType IIType III
Features and locationNormally functioning mouth and an accessory mouth with non-specific locationDuplication tissue is fused with true oral cavityDuplication tissue fused to true oral structures that is centrally located
Duplication compositionMay contain most of the oral cavity structures with upper and lower lipsUpper lip with maxilla, or lower lip with mandibleSoft tissue and bony structures of the oral cavity
Differentiation of duplication tissueModerate to poorGood to moderatePoor
Association with other anomalies++++++