Brushing pet's teeth: What do you think?

When my dad took his daschund to get his teeth cleaned professionally by a vet, they gave him a sedative so he wouldn't get stressed and he slept through it. Is that standard procedure?

Pretty much since I don't any dog woth like to hear those whirrring sound of dental equipment. They should have sused the same type of stuff they use on people so imagine the terror we all we when it's time for or dentist visit..wouldn't you want to sleep through it? LOL
   
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Dentists and needles and all that stuff doesn't really bother me. It's also my understanding that professional cleaning should be done at least once a year, or is it needed more frequently?