NEW ZEALAND (1893) Nitrous Oxide. 1 penny stamp with advertisement on back for "S. Myers & Co. Dentists, Christchurch. Nitrous Oxide Gas - Painless Extraction. Scott No 61, Yvert No 60.
AVAILABLE AT $30
U.S.A. (1949) Tube of toothpaste. Salt. Red meter cancellation on piece Pitney Bowes No 73307: "Try Worcester Salt tooth paste. Especially good for the gums. Delightfully refreshing."
AVAILABLE AT $25
FRANCE (1951) Dental hygiene. Advertising roller cancel on envelope. Hygiène Dentaire Chemin de la Santé.
AVAILABLE AT $20