The town began adding fluoride to the water supply again on Nov. 8, according to local officials. Needham had been unable to get fluoride for several weeks because of a shortage experienced by its supplier, LCI Ltd. Officials had expected not to receive any fluoride until January, said William Wanberg, the town’s water treatment manager, but the town was able to acquire 800 gallons on an emergency basis from another company. The chemical is widely added to public water supplies to combat tooth decay.