Any tooth movement caused by a force not acting through the center of resistance can be thought of as a combination of which two actions?

Any tooth movement caused by a force that does not act through the center of resistance will indeed involve a combination of translation and rotation.

When an external force is applied to a tooth, it tends to move the tooth in a direction that aligns with that force. If the force is applied directly through the center of resistance, the tooth will translate, or move, directly as a whole unit without any tipping or rotational movement. However, if the force is applied away from the center of resistance, the resulting movement will be a combination of both translation and rotation.

The translation represents the general movement of the tooth in response to the force, while the rotation describes any tilting or tipping about the center of resistance as part of that movement. This understanding is fundamental in orthodontics as it impacts how various appliances and forces are used to achieve desired tooth positioning.

Other options such as pivoting and lateral movement, or compression and expansion, do not accurately capture the mechanical principles that govern how teeth respond to forces in the context of orthodontic mechanics. Understanding these two specific actions is key to evaluating and predicting the outcomes of orthodontic treatment.