I don't think it is true that all fruitarians or those who eat a lot of fruit have problems with their teeth. Nearly two years ago I switch my diet to mostly raw foods with a high percentage of fruit. When I made the change I was aware of the potential for teeth problems. I therefore was very careful to brush my teeth after eating and to floss. About a year into the diet I stated noticing that my teeth were decaying and my gums were receding. I was in denial at first. I thought they were stained from the fruit or minerals. Anyhow, I now realize that the acid from the fruit was causing part of the problem. Also, the brushing wore away a lot of the enamel and part of the gums. Now I bush a max of twice a day and floss very rarely. I use tooth picks and pressurized water to clean in between the teeth. Vitamin D, Calcium, and phosphorus have been helped in bringing my teeth back the their former state. Vitamin C is also important for the gums and a little MSM too. Lastly sipping water or rinsing your mouth out during and after meals works to neutralize the acid on the teeth. :)