Hi,
The verb "were cleaned" in the sentence "During my checkup, my teeth were cleaned by the dental technician" is in the passive voice.
In the passive voice, the subject of the sentence is acted upon by the verb, rather than performing the action itself. In this case, the subject of the sentence is "my teeth" and the verb "were cleaned" indicates that the teeth received the action of being cleaned.
To determine whether the verb is transitive or intransitive, we need to consider if the action of the verb requires an object. In this case, the verb "cleaned" requires an object, which is "my teeth." Therefore, the verb "were cleaned" is transitive.
In summary, the sentence is in the "passive" voice and the verb "were cleaned" is "transitive" as it requires an object.
I hope that this helped you. :)