Caries susceptibility of human fluorosed enamel and dentine

Waidyasekera, P.G.K.; Nikaido, T.; Weerasinghe, D.D.S.; Wettasinghe, K.A.; Tagami, J.

doi:10.1016/j.jdent.2006.10.008

« Previous Next »Journal of Dentistry
Volume 35, Issue 4 , Pages 343-349, April 2007

Caries susceptibility of human fluorosed enamel and dentine

P.G.K. Waidyasekera
- Cariology and Operative Dentistry, Department of Restorative Sciences, Graduate School, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8549, Japan
- Corresponding author. Tel.: +81 3 5803 5483; fax: +81 3 5803 0195.
T. Nikaido
- Cariology and Operative Dentistry, Department of Restorative Sciences, Graduate School, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8549, Japan
D.D.S. Weerasinghe
- Cariology and Operative Dentistry, Department of Restorative Sciences, Graduate School, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8549, Japan
K.A. Wettasinghe
- Department of Restorative Dentistry, Faculty of Dental Sciences, University of Peradeniya, Peradeniya, Sri Lanka
J. Tagami
- Cariology and Operative Dentistry, Department of Restorative Sciences, Graduate School, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8549, Japan
- Center of Excellence Program for Frontier Research on Molecular Destruction and Reconstruction of Tooth and Bone, Tokyo Medical and Dental University, Tokyo 113-8549, Japan

Received 31 July 2006; received in revised form 23 October 2006; accepted 27 October 2006.

Abstract

Objective

Objective of our laboratory study was to determine the impact of dental fluorosis severity on the formation of caries in the human enamel and dentine.

Materials and methods

Thirty-three human molars were grouped according to modified Thylstrup–Fejerskov index (TFI) into normal (N, TFI 0), mild fluorosis (ML, TFI 1–3) and moderate fluorosis (MD, TFI 4–6). Three mesio-distal sections were made in corono-apical axis of the tooth, giving enamel and dentine samples. They were embedded in an epoxy resin, and polished. Half of the polished surface was covered with an acid resistant varnish and immersed in standard acidified buffer solution (pH 4.5) for 48h to create artificial caries lesions. They were treated with 5% NaOCl for 45min and sectioned longitudinally along the center into two halves. Cut surfaces were polished and observed under a confocal laser scanning microscope for depth of demineralization. Morphology of the demineralized zones was observed under a field emmision scanning electron microscope (FE-SEM). Data were analyzed using one-way ANOVA and Sheffe test (p=0.05).

Results

Statistically significant difference in depth of demineralization was found between N and MD groups (p=0.046) in the enamel, and between N and ML (p=0.002), N and MD (p<0.001), ML and MD (p=0.029) in dentine. FE-SEM observation of the normal enamel showed direct dissolution with large fissures. Spongy appearance of intertubular dentine gradually disappeared from N to MD.

Conclusions

Moderately fluorosed enamel showed a significant caries resistance. In contrast, mild and moderately fluorosed dentine was significantly caries susceptible in vitro.

Keywords: Dental fluorosis, Enamel caries, Dentinal caries