English Idioms and Idiomatic Expressions 

Idioms Body:  Tooth - Teeth
from: 'a have a sweet tooth'   to:  'teething problems'

• (have a) sweet tooth
  • Someone who has a sweet tooth enjoys eating sweet things like sugar, pastries, chocolate, etc.
    "My mother will be delighted if you bring her chocolates - she's got a sweet tooth."
    
    
• long in the tooth
  • If you say that someone is long in the tooth, you mean that they are getting old, or that you think they are too old to be doing something.
    "She’s a bit long in the tooth to be wearing skirts like that, isn’t she ?"
    
    
• by the skin of one's teeth
  • If you manage to do something by the skin of your teeth, you succeed in doing it but you almost fail.
    "The traffic was so heavy I thought I'd miss the train, but I caught it by the skin of my teeth."
    
    
• grit your teeth
  • When you are determined to do something in spite of the difficulties involved, you grit your teeth.
    "To reach safety I had to grit my teeth and wade through the mud."
    
    
• lie through your teeth
  • If you lie through your teeth, you lie openly and brazenly, knowing that what you are saying is completely false.
    "I saw him breaking the window. If he denies it, he's lying through his teeth."
    
    
• like pulling teeth
  • Something that is like pulling teeth is extremely difficult to obtain, especially if trying to extract information from someone.
    "Getting him to talk about his job was like pulling teeth!"
    
    
• sink one's teeth into (something)
  • If you sink your teeth into something, you do it with a lot of energy and enthusiasm.
    "When Julie got promoted, she immediately sank her teeth into her new job."
    
    
• teeth chattering
  • If your teeth are chattering, you are extremely cold.
    "Was I cold? My teeth were chattering!"
    
    
• teething problems
  • The difficulties encountered during the initial stage of an activity or project are called teething problems.
    "We had some teething problems when we first opened the bookshop, but now everything is okay."