National Dental Examining Board of Canada (NDEB) Practice Exam

Mouth breathing is commonly associated with which Angle's Class?

1. Class I

2. Class II Div 1

3. Class II Div 2

4. Class III

The correct answer is: Class II Div 1

Mouth breathing is most commonly associated with a dental condition known as Angle's Class II Div 1 malocclusion. This type of malocclusion is characterized by an overbite, which is when the upper teeth significantly overlap the lower teeth. Mouth breathing can occur as a result of the lips being unable to fully close due to the excessive overbite, leading to air being constantly breathed in through the mouth. Option A, Class I, is incorrect because it does not involve an overbite and is considered a normal bite. Option C, Class II Div 2, also does not involve an overbite, but instead has a deep bite or excessive overlap of the upper front teeth over the lower front teeth. Option D, Class III, is incorrect because it involves an underbite, where the lower teeth protrude past the upper teeth, and does not typically lead to mouth breathing. Therefore, option