The interproximal cleaning apparatus includes a gas reservoir (12) containing a compressed gas, such as CO2, in both liquid and gaseous states. A siphon tube (20) extends down into the liquid region of the gas reservoir when the apparatus is in an upright position. The siphon tube connects the reservoir to a metering valve (18) which has a metered volume to accommodate an amount of liquid compressed gas which is sufficient for good liquid droplet cleaning when it decompresses and forms a gaseous stream, without damage to the dental regions of the user. If the apparatus is severely tilted or turned upside down, gaseous CO2 or a combination of gaseous and liquid CO2 will enter the siphon tube and then the metering valve. The size of the metering valve will limit the volume of the gaseous CO2 to a safe amount, both when liquid CO2 or gaseous CO2 are applied to the metering valve.