A spoon, a dental instrument used to carefully remove decay, is sometimes employed when the decay in dentin reaches near the pulp. Some dentists remove dental caries using a laser rather than the traditional dental drill. A Cochrane review of this technique looked at Er:YAG (erbium-doped yttrium aluminium garnet), Er,Cr:YSGG (erbium, chromium: yttrium-scandium-gallium-garnet) and Nd:YAG (neodymium-doped yttrium aluminium garnet) lasers and found that although people treated with lasers (compared to a conventional dental "drill") experienced less pain and had a lesser need for dental anaesthesia, that overall there was little difference in caries removal. Another alternative to drilling or lasers for small caries is the use of air abrasion, in which small abrasive particles are blasted at decay using pressurized air (similar to sand blasting). Once the cary is removed, the missing tooth structure requires a dental restoration of some sort to return the tooth to function and aesthetic condition. Restorative materials include dental amalgam, composite resin, glass ionomer cement, porcelain, and gold. Composite resin and porcelain can be made to match the color of a patients natural teeth and are thus used more frequently when aesthetics are a concern. Composite restorations are not as strong as dental amalgam and gold; some dentists consider the latter as the only advisable restoration for posterior areas where chewing forces are great. When the decay is too extensive, there may not be enough tooth structure remaining to allow a restorative material to be placed within the tooth. Thus, a crown may be needed.
Serious illness has followed ingestion of 7.5 g (0.26 oz). The mean lethal oral dose for an adult is estimated at 45 g (1.6 oz).The anesthetic use of chloroform has been discontinued because it caused deaths due to respiratory failure and cardiac arrhythmias. Following chloroform-induced anesthesia, some patients suffered nausea, vomiting, hyperthermia, jaundice, and coma due to hepatic dysfunction. At autopsy, liver necrosis and degeneration have been observed.Chloroform has induced liver tumors in mice and kidney tumors in mice and rats. The hepatotoxicity and nephrotoxicity of chloroform is thought to be due largely to phosgene. Conversion to phosgene
Chloroform converts slowly in air to the extremely poisonous phosgene (COCl2), releasing HCl in the process. 2 CHCl3 + O2 → 2 COCl2 + 2 HClTo prevent accidents, commercial chloroform is stabilized with ethanol or amylene, but samples that have been recovered or dried no longer contain any stabilizer. Amylene has been found ineffective, and the phosgene can affect analytes in samples, lipids, and nucleic acids dissolved in or extracted with chloroform. Phosgene and HCl can be removed from chloroform by washing with saturated aqueous carbonate solutions, such as sodium bicarbonate. This procedure is simple and results in harmless products. Phosgene reacts with water to form carbon dioxide and HCl, and the carbonate salt neutralizes the resulting acid.Suspected samples can be tested for phosgene using filter paper (treated with 5% diphenylamine, 5% dimethylaminobenzaldehyde in ethanol, and then dried), which turns yellow in phosgene vapor.