Dental caries is the destruction of the tooth structure in the presence of organic acids
produced by cariogenic bacteria located in the dental biofilm (Dowker et al., 1999 and
Robinson et al., 2000).Tooth enamel comprises 90% substituted hydroxyapatite (Ca10 (PO4)6(OH)
2), which is subjected to consecutive cycles of demineralization and remineralization. This
is an interrupted process, with periods of remineralization and demineralization occurring,
depending on the state of the oral environment in terms of the prolonged accumulation and
retention of bacterial plaque on the enamel surface (Aoba, 2004).
Oral bacteria ferment carbohydrates to produce organic acids which lower the pH and cause the
subsurface dissolution of the hydroxyapatite crystals. Under normal physiological conditions
(pH7), saliva is supersaturated with calcium and phosphate ions which diffuse into the
vacancies created during acid-mediated demineralization episodes (Dowker et al., 1999 and
Robinson et al., 2000). The demineralization of enamel (white spot lesions) is a significant
problem during and after orthodontic treatment with prevalence 71.1% and various preventive
measures have been suggested to minimize the incidence (Derks et al., 2004 and Al Maaitah et
al., 2011).