Title: 3274 - Effect of Fluoride on the Natural Sound Tooth Surface


Masaki Kambara (Presenter)
Kambara Global Health Institute

Hiroshi Itoh, National Institute of Advanced Industrial Science and Technology
Motoharu Shichiri, National Institute of Advanced Industrial Science and Technology
Takashi Ikeo, Osaka Dental University


Objectives: The purpose of our study is to observe the visuable micro-change of surface in natural tooth by fluoride solution with time.

Methods: The first bicuspid teeth were corrected which were extracted for the orthodontic treatment. After extraction, teeth were washed by ultrasonic cleaning machine. The measuring samples were made to cut out the enamel blocks and small enamel samples were prepared at the size of 5×5×1 mm (surface side of enamel kept natural). The surface changes of natural enamel samples were observed by Atomic Force Microscopy (AFM) after application of fluoride solutions (0, 100, 1,000 and 9,000ppmF). And small enamel samples were observed by AFM attached with high speed video camera under the flow of fluoride solutions (0 – 9,000ppmF).
This study was conducted after permitted by the Ethics Committee of Osaka Dental University. There is no conflict of interest.

Results: The obtained images (1μm unit) of natural enamel surfaces showed several shapes. One is that elliptical enamel crystal blocks are arranged and stacked in order, and the others is that there are several irregularly shaped enamel crystal blocks (square, circular, irregular) at random. Few spherical CaF2 like materials were found on the surface of natural teeth after application of fluoride 1,000ppmF and many round CaF2 like materials were scattered after 9,000ppmF.
For images with high speed AFM scanner (up to 10 flames/s), spherical shape CaF2 like material appeared between enamel crystal blocks with increasing fluoride concentration. The formation of CaF2 like materials on the surface of natural enamel in this continuous image was different from the images in bovine enamel which has been reported.

Conclusions: These results suggest that CaF2 like materials are formed to fill the space between the enamel blocks, resulting in a smooth enamel surface after fluoride application in natural teeth.

Disclosure Statement:
The submitter must disclose the names of the organizations with which any author have a relationship, the nature of the relationship, and the clinical or research area involved. The following is submitted: none