Does a frankel ortho appliance straighten teeth?

Not directly: This is one of a class of appliances seeking to correct orthopedic issues of malocclusion relating to jaw size and position. This type of treatment is often used as a prelude to other technologies that actually straighten teeth. I'm sure the orthodontic specialists will weigh in with more detail.

Indirectly: Frankel orthodontic appliance is used in a growing individual to help develop the upper and lower jaw size completely so there is adequate room for all the teeth to erupt in a better alignment with enough space.

Secondarily: The frankel actually makes changes to the jaws. The changes to the jaws create more space to allow the teeth to align better. There are many newer types of expanders that can also make this same type of changes.

Marginally: A Frankel Appliance is "functional appliance" designed to harness muscle function to affect direction and amount of jaw growth in a child. It also has very limited tooth aligning capabilities. DOES NOT WORK for adults that are no longer growing...works best before about age 10. My experience is that the appliance seems to be very fragile and breaks a lot. Must be worn a full 14 hrs/day.

Sort of: Love your question as, believe it or not, I was the FIRST Frankel appliance patient in the united states when I was a kid (Dr. Frankel stayed at my house-- my dad is an orthodontist). Frankel's help develop the upper and lower jaw size to make room for all the teeth to erupt with enough space. They are only for developing kids