The singular possessive form of the noun dentist is dentist's.
example: The dentist's waiting room was empty.
dentists
dentist's
The singular noun is tooth.The singular possessive noun is tooth's.Example: The dentist smoothed the tooth's chipped edge.
The possessive form is Amos's.
The singular form is goose; the singular possessive form is goose's.The plural form is geese; the plural possessive form is geese's.
Quantum is singular, not singular possessive. The singular possessive form is quantum's.
The singular possessive form is speculum's.
The singular possessive form is frontiersman's.
The singular possessive form is aircraft's.
The singular possessive form is week's.
The singular possessive form is contralto's.
The singular possessive form is herd's.
The singular possessive form is heart's; the plural possessive form is hearts'.
The singular noun is tooth.The singular possessive noun is tooth's.Example: The dentist smoothed the tooth's chipped edge.