What is crossbite?

What is crossbite?

• A. Mandibular teeth lateral on one side and medial on the other
• B. Maxillary incisors ahead of mandibular incisors
• C. Both arches align evenly
• D. No occlusal contact

Answer: (A)

Crossbite is a transverse misalignment where the upper teeth do not bite over the lower teeth as they should. In a unilateral crossbite, the lower teeth can sit more toward the cheek (lateral) on one side relative to the uppers, while on the other side they sit closer to the midline (medial) relative to the uppers. That pattern—mandibular teeth being lateral on one side and medial on the other—fits a crossbite scenario, where the arches don’t align properly side to side. The other options describe situations that aren’t crossbite: maxillary incisors ahead of the mandibular incisors reflects an excessive overjet rather than a transverse mismatch; both arches aligning evenly is normal occlusion; no occlusal contact points to an open bite or lack of contact, not a crossbite.

Crossbite is a transverse misalignment where the upper teeth do not bite over the lower teeth as they should. In a unilateral crossbite, the lower teeth can sit more toward the cheek (lateral) on one side relative to the uppers, while on the other side they sit closer to the midline (medial) relative to the uppers. That pattern—mandibular teeth being lateral on one side and medial on the other—fits a crossbite scenario, where the arches don’t align properly side to side.

The other options describe situations that aren’t crossbite: maxillary incisors ahead of the mandibular incisors reflects an excessive overjet rather than a transverse mismatch; both arches aligning evenly is normal occlusion; no occlusal contact points to an open bite or lack of contact, not a crossbite.