Abstract
Enamel surface changes caused by the topical application of fresh lemon juice were observed microscopically. Freshly expressed lemon juice was used, because tests revealed that the pH of the juice declines with the passing of time.
As a preliminary experiment, topical application of the juice was made on five extracted teeth, in this order: 1 min. application, 1 min. irrigation, and finally replica taking for microscopic observation. This procedure was repeated twenty times for each case.
One application caused no apparent changes on the tooth surfaces. Two applications caused changes in one tooth, and three applications caused changes in two teeth. All teeth showed some changes, more or less, after five applications. After seven applications, the enamel rod ends became visible in the whole microscopic field in all five teeth.
For experiments with living teeth, the following procedure was employed: 1 min. topical application and replica taking once a day for twenty days. The experimental group consisted of ten young males aged twenty to twenty-four, with normally healthy upper central incisors. The examinees led a normal every-day life, including meals and toothbrushing, except for the daily application of lemon juice. The application was continued on the left central incisor for ten days and observation by the replica method was made for twenty days. On the right central incisor, the application was performed until the enamel rod ends became visible in the whole microscopic field, and the replica was taken for twenty days.
The enamel rod ends became visible in the whole microscopic field after three or four days' application in both experimental groups. The changes occurred faster in living teeth than in extracted ones, and the changes after stopping the application varied from case to case. For instance, one showed disappearance of the enamel rod ends on the day after the application stopped, while another did not show any changes even ten days after the application ended.
Judging from replica observation, changes that appeared early in the experiment took longer to disappear than changes that appeared later.
