You might not think “improvisation” and “dentistry” would go together. In fact, you might dread the slightest possibility. But you are not Andrew Kratzat.

The Ann Arbor-based composer bassist comes to Lansing JazzFest behind a CD of tradition-stretching compositions, played by a Who’s Who of the University of Michigan jazz crowd.

It’s a tuneful, if quirky, mix of acoustic sounds, well on this side of the avant-garde. Yet, for his own obscure reasons, Kratzat has chosen to package it in a horrific-looking sleeve and call it “The Dentist.”

“It’s kind of an in-joke,” he confessed. The sauntering, suave title track is a tribute to one of Kratzat’s favorite jazzmen, eccentric saxman Tim Berne.

Berne is known for his long, labyrinthine compositions and exploratory (some might say, root canal-like) tenor style. While playing clubs in New York, Kratzat heard the strange (and untrue) rumor that Berne was a dentist on the side.

“I’d imagine Tim Berne as my dentist, and how horrible that would be,” Kratzat said.

Kratzat’s music is more sedate than Berne’s, and more tethered to jazz tradition, but the two musicians share a dry wit. The cover of Kratzat’s CD features a bloody, smiling dentist, with Berne’s thick black eyebrows.

As a highly sought-after bassist, Kratzat plays in a lot of other bands, including the busy Hot Club of Detroit. When gets the chance to do his own projects, he shapes and presents them as he pleases, without regard for commercial appeal.

“I don’t have to worry about selling tons of CD and booking tons of shows,” he said. “I already have tons of shows as a sideman.”

Kratzat’s personality comes out most in his original compositions, which run from gentle musing to hard kicks at hard bop.

The jazz tradition nurtures Kratzat, but does not smother him. “I listen to Monk and Coltrane and Miles for fun, all the time, every day,” he said. “Their music is always in whatever I’m doing.”

Kratzat grew up in Fort Wayne, Ind., where his dad played French horn and piano.

He grew up listening to classical music, and he longed to play cello after seeing Yo-Yo Ma on “Sesame Street.” But there were too many cellists in his high school orchestra, and he was shunted toward the acoustic bass. By then, he was already playing guitar and electric bass.

Kratzat took to acoustic bass so quickly the school’s jazz band recruited him. “I told them I wasn’t interested, but I ended up doing it anyway, and it became my passion,” Kratzat said.

His interest in jazz was sparked by CDs of the Ray Brown trio with Gene Harris, in addition to the typical light-bulb moments, like hearing Miles Davis’ “Kind of Blue” and Dave Brubeck’s “Time Out.”

Films fed Kratzat’s muse, too.

Before coming to school at U of M, he spent hundreds of hours watching the pre- 1975 work of Fellini, Kurosawa, Bergman and the French New Wave.

“I found I was drawn to strange narratives, plots that were not so easily distinguishable,” he said.

During Kratzat’s bass solos, he almost seems to change instruments, from horn to drum to piano, and his compositions are similarly hard to predict — Fellini-esque, you could say. “I got away from head-solo-head and went with the journey,” he said.