Intraoral Class II distalizers have the major disadvantage of:

 # Intraoral Class II distalizers have the major disadvantage of:

a) the need for patient compliance

b) a force vector passing coronally to the maxillary arch’s center of resistance

c) anterior anchorage loss

d) an inability to be used simultaneously with multibracket appliances

The correct answer is:

c) Anterior anchorage loss

Explanation:

Intraoral Class II distalizers, such as the Pendulum appliance, Distal Jet, or Forsus, rely on posterior force application to move the maxillary molars distally. However, a major drawback is anterior anchorage loss, meaning:

As the maxillary molars move distally, the anterior teeth tend to drift forward, leading to proclination of the incisors.

This can compromise the correction of a Class II malocclusion if not properly controlled with anchorage reinforcement.

Why not the other options?

(a) The need for patient compliance → Not true for most fixed distalizers (e.g., Pendulum, Distal Jet), but true for removable appliances like elastics or headgear.

(b) A force vector passing coronally to the maxillary arch’s center of resistance → This is a concern in some cases but not the primary disadvantage.

(d) An inability to be used simultaneously with multibracket appliances → Many distalizers can be used alongside braces (e.g., Forsus, Carriere Motion Appliance).