It may be associated with dry mouth and low saliva. From birth to 6 months, infants can suffer from protein deficiency leading to abnormal salivary gland development, which can deprive the teeth of saliva protection and predispose them to caries, leading to smelly teeth. In addition saliva also helps to clean the mouth and remove particles that cause unpleasant odours. In addition, poor feeding habits and/or extended breast or bottle feeding, extended beyond the normal time for a child to transition from stopping breastfeeding or quitting bottle feeding to solid food, combined with poor oral hygiene care practices and the anatomical and tissue structure characteristics of the milk teeth can often lead to earlier or rampant caries, which can predispose to tooth odour.