It is clearly pointed out in the book that tooth loss is a symbol of "family funeral". Dreaming of tooth loss is indeed a sign of bad luck, because teeth are exposed bone tissue, and tooth loss means "separation of flesh and blood." I suggest your sister pay more attention to the health problems of parents, relatives and other elders in the family. Maybe it's her own phone number that can avoid this kind of bad luck. This explanation is widely circulated and has its own reasons, reminding everyone not to ignore the health of their families.
Dreaming that you have lost your teeth means that there may be problems with your family's health, reminding dreamers to pay more attention to their family's health.
Dreaming that one's teeth have fallen out indicates that the dreamer may have a quarrel with others, reminding the dreamer to control his emotions, not to be impulsive, and to put harmony first in everything.
Dreaming of pulling teeth means growing up and becoming mature.