Is there a time limit on D9230 Nitrous Oxide? How often can it be billed on a single 2 hour visit. Thank you!October 1, 2015 by Admin « Back to Previous Page Answer Question ▲0 ▼ ♥ 0 Marked as spamAsked on October 1, 2015589 viewsFollowUnfollow ▲1 ▼✔ Private answerD9230 is billed out once as a single code per visit, it does not have a time limit.Marked as spamAnswered on October 2, 2015 « Back to Previous Page Post your AnswerAttach YouTube/Vimeo clip putting the URL in brackets: [https://youtu.be/Zkdf3kaso] Notify me of follow