Green’s Dictionary of Slang

mompyns n.

the teeth.

c.1460		Towneley Mysteries ‘Prima Pastorum’ (3) line 209: Let vs go foder Oure mompyns .
c.1475		Lydgate Minor Poems 30: Thy mone-pynnes bene lyche old yuory Here are stumpes feble and her are none .
1523–4		Skelton ‘How the Douty Duke of Albany’ in Henderson Complete Poems (1948) 406: I shrewe thy Scottishe lugges, Thy munpynnys, and thy crag.