It's a frequent trivia question, and one that many otherwise reputable reference books get wrong:
Guaraldi scored 15 Peanuts TV specials (from A Charlie Brown Christmas through It's Arbor Day, Charlie Brown), one big-screen film (A Boy Named Charlie Brown) and two half-hour TV documentaries (the unsold A Boy Named Charlie Brown and Charlie Brown and Charles Schulz).
Few people realize, however, that Guaraldi also had a hand in three more animated Peanuts projects.
Sort of.
Guaraldi's untimely passing in February 1976 left Lee Mendelson in an obvious bind, when it came time to score the next Peanuts TV special, It's Your First Kiss, Charlie Brown. Perhaps after considerable soul-searching, Mendelson shifted from jazz to a more pop-oriented sound, teaming former psychedelic rocker Ed Bogas with singer/songwriter Judy Munson. That likely was a shrewd decision; rather than have somebody else try to imitate Guaraldi's distinctive Peanuts sound — which clearly would have been impossible, and perhaps even unwise — Mendelson went in an entirely different direction. Successive Peanuts TV specials remained in that pop realm for the next dozen years.
At the same time, though — shortly after Guaraldi's death — when Charlie Brown and his friends accepted a few outside "moonlighting" assignments, Mendelson instead returned to his Main Man ... which is how Vince scored three Peanuts public-service shorts from the grave.
Well, not exactly ... although it might have seemed that way, to people who weren't paying attention.
Mendelson, animator Bill Melendez and Charles M. Schulz teamed with the American Dental Association to produce a pair of 5-minute shorts: 1977's Tooth Brushing and 1980's It's Dental Flossophy, Charlie Brown. Both films were designed to be shown in schools, as a means of encouraging children (and their parents) to take better care of their teeth.
Tooth Brushing begins as Charlie Brown happily concludes a visit with his dentist — apparently not having suffered any cavities — and then shares what he learned with Linus and Snoopy. As Charlie Brown explains how to brush and floss properly, we watch both Linus and Snoopy demonstrate these desired techniques. The film draws most of its humor from the fact that Snoopy is using Lucy's tooth brush, which the neighborhood's champion fussbudget fails to realize when she joins the bathroom gathering. As Charlie Brown and Linus react with hilarious expressions of nausea, Lucy uses the same brush to prove that she's the best brusher in town.
The music track behind this action is constant, and consistent: several variations of "The Heartburn Waltz," lifted from the score to Be My Valentine, Charlie Brown, which had debuted January 28, 1975. This engaging theme was heard half a dozen times during the course of that Peanuts TV special, but never quite the same way twice; Guaraldi vamped and noodled through numerous arrangements and Hammond B3 variations, and he also recorded more versions than ultimately were used in the show. Thus, sharp-eared listeners who hang on every note during Tooth Brushing will detect a few versions of "The Heartburn Waltz" that are lifted directly from Be My Valentine, while at least one is an alternate take that never made it into the soundtrack.
Tooth Brushing is available for viewing on YouTube, and you'll find that it's cute and instructive, as well as being a nice showcase for Guaraldi's music.