Hi, and thanks for your question
There’s actually not a lot of information out there about the possibility of passing trichomoniasis through oral sex. The American Centre for Disease Control and Prevention states that it is theoretically possible to pass the infection this way but there are few reports to back this up and demonstrate an actual risk. Have a look at what they say on the Centre for Disease Control and Prevention webpage.
Otherwise, I would continue to abstain from any sexual contact as directed by your testing provider. You may also want to revisit the clinic where you got tested and ask them if they recommend taking the treatment again to prevent an infection in the mouth from any oral sex contact after the initial treatment.
Let us know if this does not answer your question or if you have any more questions or concerns.