Which classification indicates a normal occlusion?

A normal occlusion is classified as Class I. In this classification, the relationship between the maxillary and mandibular first molars is such that the mesiobuccal cusp of the maxillary first molar aligns with the mesiobuccal groove of the mandibular first molar. This creates a proper bite relationship where the teeth fit together comfortably and effectively, allowing for optimal function and aesthetics.

Class II and Class III represent malocclusions—situations where the upper and lower teeth do not meet properly. Class II indicates a retruded mandible, where the lower teeth are positioned further back than the upper teeth, while Class III is characterized by a protruded mandible, where the lower teeth extend beyond the upper teeth. Class IV is not a standard classification within the Angle classification system of occlusion, further reinforcing that Class I is indeed the correct choice for identifying normal occlusion.