Visit a dentist please, this issue can only be treated definitively by physically checking the patient, as a variety of factors might be involved

Get an xray of front 4 teeth.if there is any infection  associated, get root canal treatment done for front teeth  ,stress cancer due to dentin hypersensitivity also.

Is there any discomfort while talking? Does she feel sensitivity from hot, cold or sweet? Any pain or irritation? Swollen gum? Teeth cutting needs to be done to make any crowns. There shouldn’t be any space in between the crowns. If there’s any infection around the roots of the teeth, root canal treatment should be done. A Dental X-ray is required to make a proper diagnosis.

Do visit a local dentist for treatment and physical evaluation.

From the description provided, Suggest you to get an consultation from respected dentist for the proper evaluation