Green’s Dictionary of Slang

(orig. US) teeth.

1915		Ogden Standard (UT) 20 Mar. 19/3: The leading lady [...] paring her finger nails by placing them carefully between [her] ‘pearly whites’.
1935		A.J. Pollock Und. Speaks 86/2: Pearly whites, the teeth.
1953		‘John Eagle’ Hoodlums (2021) 34: He fought back the urge to smear her face, just once. Scatter the pearlies. Ruin the lips.
1967		P. Thomas Down These Mean Streets (1970) 126: Down South, if one ain’t real careful, he can grow up smilin’ his ass off and showin’ pearly whites till his gums catch pneumonia.
1978		J. Wilson Mulatto 249: ‘Fine set of pearlies,’ he gloated.
1989		M. Walker How to Kiss a Crocodile 75: [H]e was clearly unashamed at his decaying collection of not so pearly whites.
1997		(con. 1970s) G. Pelecanos King Suckerman (1998) 127: You shoulda seen those pearly whites.
2007		N. McCall Them (2008) 60: He was kind of cute with his thick, untamed hair and pearly whites.
2018		G. Gilmore Base Nature [ebook] Two sets of pearly whites visble for less than a second.