In Sitswana, thw class Ji-Ma is Le-Ma. And so, both 'leina' (name) and 'leino' (tooth) 'take the prefix ma- in the plural'. And therefore 'maina' and 'maino' respectively. The latter feature prominently in juvenile speech. The plural form 'mênô' (in mature apeech) is formed by coalescence of the vowels a-i. The same coalescence, however, does not apply to the noun 'maina'.
Interestingly, -ina is a root verb meaning, dip or immerse in liquid.