Oral hygiene against periodontitis

A 38 year old woman with severe periodontitis is in her 10th week of pregnancy when the dental assistant tries to discuss oral hygiene and future appointments for scaling. The patient becomes angry and says that she can live with bleeding gums and brown teeth from her former smoking habit. Then also says that she is not interested in learning about dental hygiene because her teeth will eventually fall out. How could the dental assistant convince the patient importance of hygiene.