COA Dental Anatomy & Oral Development 3

Question 1

In Angle's classification, Class I occlusion is characterized by which molar relationship?

Accepted Answer

The mesiobuccal cusp of the maxillary first molar occludes in the buccal groove of the mandibular first molar

Answer

Angle's Class I (neutrocclusion) is defined by the mesiobuccal cusp of the upper first molar occluding in the buccal groove of the lower first molar, indicating a normal anteroposterior skeletal relationship.

Question 2

Angle's Class II malocclusion is also referred to by which descriptive term?

Accepted Answer

Disto-occlusion

Answer

Class II is called disto-occlusion because the lower first molar is positioned distal (posterior) to its ideal Class I position, resulting in the mandible appearing retruded.

Question 3

What orthodontic term describes the vertical overlap of the upper anterior teeth over the lower anterior teeth?

Accepted Answer

Overbite

Answer

Overbite measures the vertical overlap of the maxillary anterior teeth over the mandibular anterior teeth; a normal overbite is approximately 2–3 mm.

Question 4

The horizontal distance between the labial surface of the upper incisors and the labial surface of the lower incisors, measured parallel to the occlusal plane, is called:

Accepted Answer

Overjet

Answer

Overjet (also called horizontal overlap) measures the horizontal protrusion of the maxillary incisors beyond the mandibular incisors; a normal overjet is approximately 2–3 mm.

Question 5

Which anatomical plane divides the face and body into equal left and right halves and is used as a reference in orthodontic diagnosis?

Accepted Answer

Midsagittal plane

Answer

The midsagittal (median) plane divides the body into equal left and right halves and serves as a critical reference for assessing facial symmetry and dental midline discrepancies in orthodontics.

COA - Certified Orthodontic Assistant Practice Test

COA - Certified Orthodontic Assistant Practice Test

COA Dental Anatomy & Oral Development 3