After one takes a Driving Safety Course in Texas, a record of such is placed on the driver licence.
However, the course is required not only for dismissing the tickets, but is also available for some sort of extra insurance discounts, too.
As such, it would indeed appear that one could still claim to have a clean record, even with the presence of the course on the record.
(As per the notion of not creating prejudice, I would think that the prosecutor would not be allowed to dispute such statement in front of a jury, nor to explain the exhaustive list of reasons that the record might originate from. Voir dire would likewise be a separate question in such circumstance.)
P. S. Additionally, it's explicitly not allowed to be used for adverse actions, as per http://www.statutes.legis.state.tx.us/Docs/CR/htm/CR.45.htm#45.0511
Art. 45.0511. DRIVING SAFETY COURSE OR MOTORCYCLE OPERATOR COURSE DISMISSAL PROCEDURES. (a) Except as provided by Subsection (a-1), this article applies only to an alleged offense that:
(n) A charge that is dismissed under this article may not be part of a person's driving record or used for any purpose.
(o) An insurer delivering or issuing for delivery a motor vehicle insurance policy in this state may not cancel or increase the premium charged an insured under the policy because the insured completed a driving safety course or a motorcycle operator training course, or had a charge dismissed under this article.