Abstract: A cartridge system for purifying water supplied to a dental unit and dynamic dental instrument has at least one disposable cartridge element having an activated charcoal resin and an iodinated anionic exchange resin containing a continuous fixed-rate release iodinated resin I.sub.(n). Iodine is released from the iodinated resin at a specified and consistent rate as water passes through the resin to maintain dental unit water purity. The activated charcoal resin functions to remove chlorine from incoming water to prevent chlorine reaction with iodine. The cartridge is installed in the water supply tubing at the point of connection to a water supply system. Tubing having inner surfaces passivated with iodine is connected to the downstream end of the cartridge. The cartridge is the principal water purification source and reinforces an existing water purification system.

Abstract: A dual cartridge system for purifying water supplied to a dental unit and dynamic dental instrument has two disposable elements, each having an iodinated anionic exchange resin containing a continuous fixed-rate release iodinated resin I.sub.(n). Iodine is released from the resin at a specified and consistent rate as water passes through the resin to maintain dental water purity. One cartridge is located in the dental unit water supply tubing. A second cartridge is located in the water supply tubing adjacent the connection to the water supply system. The iodinated biocidal resin in each cartridge neutralizes and kills disease-causing bacteria, virus, protozoa, aspirated oral flora and prevents microbial back-growth to eliminate cross-infection between dental patients.

Abstract: A system for purifying water supplied to a dynamic dental instrument has a disposable element having an iodinated resin containing a polyiodide, I.sub.5. Disease causing microorganisms in water flowing through the element are neutralized with neutralizing agents released directly into the microorganisms when the microorganisms come into contact with the resin. Residual iodine is released as water passes through the resin and remains between the element and the dynamic instrument to maintain dental unit water purity.