to the teeth
Completely, fully, as in Obviously new to skiing, they were equipped to the teeth with the latest gear. This idiom dates from the late 1300s. Also see armed to the teeth; fed to the gills.
Also, up to the or one's teeth. Fully committed, as in We're in this collaboration up to our teeth. [First half of 1900s] Both of these hyperbolic usages allude to being fully covered or immersed in something up to one's teeth.