Advanced Dental Admission Test (ADAT)

Which statement is true regarding Class III occlusion?

1. Maxillary canine contacts distally to opposing canine

2. Class III occlusion involves maximum crowding of anterior teeth

3. The mb cusp of maxillary first molar contacts mesially to the mandible’s first molar

4. All upper teeth align over lower teeth

The correct answer is: Maxillary canine contacts distally to opposing canine

Class III occlusion, commonly referred to as a "mesognathic" relationship, is characterized by specific geometric arrangements of the teeth and jaws. In this type of occlusion, the relationship between the maxillary and mandibular dental arches is such that the mandibular dental arch is positioned ahead of the maxillary arch. The statement that the maxillary canine contacts distally to the opposing canine accurately describes one of the distinctive features of Class III occlusion. In this occlusal relationship, the maxillary canine is positioned more towards the back of the mouth compared to where it would be in a normal or Class I occlusion, where it would typically contact the mandibular canine at their respective cusp heights. In contrast, Class III occlusion does not inherently create maximum crowding of anterior teeth (which can vary based on other factors like individual dental anatomy or space availability). Also, the positioning of the maxillary first molar in relation to the mandibular first molar is crucial: in Class III occlusion, the mesobuccal cusp of the maxillary first molar indeed contacts somewhat mesially to the buccal cusp of the corresponding mandibular first molar, which is different from what the statement presents. Lastly, the