There is some evidence to suggest that the use of a rubber dam may increase the survival time of dental restorations compared to the use of cotton rolls as an isolation method.[4] Decreased contamination of dental treatment with oral micro-organisms in saliva[5] There is improved visibility of the operative site (retracts the lips and cheeks, reduced mirror fogging, enhanced visual contrast)[6] Decreased (but not eliminated) chance of accidental swallowing or inhaling restorative instruments, tooth fragments or debris.[7] Should this occur, hospital admission might be necessary for a chest x-ray, and potentially an operation to remove it. Corrosive endodontic irrigants such as sodium hypochlorite (bleach) are contained, which could damage the soft tissues of the mouth and be harmful if swallowed[8] Reduction in the risk of cross-infection in the dental practice by decreasing the microbial content of splatters and air turbine aerosols produced during dental treatment[9] When rubber dams are used in association with amalgam restorations, they may reduce the person's exposure to potentially harmful adverse effects of mercury ingestion[10][11] Protecting soft tissues of oral mucosa from sharp instruments or materials. Some patients find it more comfortable to have treatment with a dental dam since there is no water in the mouth and they feel safer and more dissociated from the noise of drilling etc.[12] In some parts of the world, use of a dental dam is mandatory for procedures such as root canal therapy for reasons of safety and cross infection control, and if any injury that could have been prevented by its use occurs, it is medicolegally indefensible.