Usually, at dental appointments, the Dr. calls out arbitrary numbers; 4,6,4,6,4,5...... and you have no idea what is going on. The health of your gums is being evaluated, and any number over 3 is not a good number.
This is the measurement of the sulcus, or pocket in the gum tissue surrounding each tooth. So many people put off seeing the dentist due to anxiety or they don't think they need to because their mouth doesn't hurt. Well, your mouth doesn't need to hurt to have periodontal disease. If you wait until you experience pain, you will most likely be facing more serious problems and possibly extensive dental work.
What could have been prevented by getting regular cleanings, check-ups and practicing good home care has now ballooned to thousands of dollars in surgery and possibly losing a tooth/teeth.
A good rule of thumb is to have a professional dental cleaning every 6 months with an exam. Some people are more prone to decay or periodontitis and will need to see their dentist and hygienist more often- say every 3-4 months.