The 22 year old man in my dental chair had all the signs of a specific condition. He had severe erosion of the inside surfaces of his upper front teeth. Almost a third of his enamel had been eroded away. I had seen young women patients with the condition I was tentatively diagnosing in my mind but I had never seen a male patient with it. When the assistant stepped out of the room and we were alone I said: “You have signs on your teeth that I’ve seen in patients who have bulimia. Have you ever vomited after eating either intentionally or unintentionally?”
He was emphatic as he replied: “Me, no way, I enjoy my food too much to do that! I‘m definitely not bulimic.”
We continued our discussion about what could be causing the erosion on his teeth. When I asked if he drank soft drinks regularly he admitted to drinking about a flat a week (24 cans). When I asked about the way he drank them, whether there was anything different he said: “I hate swallowing the bubbles so I swish the [cola] around in my mouth before I swallow it”. I had heard about people “swishing” beverages in this way but this young man was the first “swisher” I had met. Apparently, people like him enjoy the feeling of soft drinks in their mouths but don’t like the feeling of the bubbles in their throat as they swallow. As they swish the soft drink around to remove the carbon dioxide bubbles the teeth become corroded. In his case there was significant corrosion.
Acidity is expressed by a pH number. Seven is neutral; below seven is acidic and above seven is alkaline. The pH scale is logarithmic; this means that each unit upward or downward is a tenfold increase in concentration from the number before. The lower the number the more acidic or corrosive the material.
- PH 7 Water
- PH 4.3-5.0 Acid rain, black coffee
- PH 3.3-4.0 Orange juice
- PH 3.0 Vinegar
- PH 2.5 Cola
- PH 1.5-2.0 Stomach acid (mainly
- hydrochloric acid)
Orange juice is ten times as acidic as coffee but cola is about 100 times stronger! Cola is very acidic and, therefore, corrosive. Those schoolyard stories of placing a bolt in a can of coke and having it dissolve are true! Added to this is the high sugar content of regular soft drinks: 6 teaspoons of sugar per can. This sugar feeds the bacteria that produce dental decay in our mouths and they produce even more acid as a waste product. It’s the acid that these bacteria produce held against our teeth by plaque which dissolves the tooth surface microscopically and makes cavities. There are no bacteria which “drill” into our teeth. It’s all done by the acid they produce.
Since the 1970’s soft drink consumption in the USA has tripled for men and doubled for women. At present the male 12-29 year old group consumes an average of 2 litres per day. Our levels in Canada are about 50% of this. Risks from this increased consumption of carbonated beverages include: obesity, nutritional deficiencies, tooth decay, diabetes, osteoporosis and heart disease.
In my young patient’s case, the remedy was simply to reduce or stop his soft drink consumption and change the “swishing” behavior. The damage to his teeth can be repaired. Bulimia, however, can be very difficult to treat. If you or a loved one has bulimia please seek professional care through a counselor trained to deal with eating disorders. Visit your dentist too, during recovery, to lessen the devastating oral effects of this disease.
Dr. Hill is a member of the American Association of Dental Sleep Medicine.