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ABSTRACT
Laser and fluoride treatments have been shown to inhibit enamel demineralization in the laboratory. However, the intra-oral effects of this association have not been tested. This study assessed in situ the effect of a Transversely Excited Atmospheric-pressure CO2 laser (λ = 9.6 µm) and the use of fluoridated dentifrice on enamel demineralization. During two 14-day phases, 17 volunteers wore palatal appliances containing human enamel slabs assigned to treatment groups, as follows: (1) non-fluoride dentifrice, (2) CO2 laser irradiation plus non-fluoride dentifrice, (3) fluoride dentifrice, and (4) CO2 laser irradiation plus fluoride dentifrice. A 20% sucrose solution was dripped onto the slabs 8 times per day. The specimens treated with laser and/or fluoridated dentifrice presented a significantly lower mineral loss when compared with those from the non-fluoride dentifrice group. The results suggested that CO2 laser treatment of enamel inhibits demineralization in the human mouth, being more effective when associated with fluoride.
KEY WORDS: CO2 laser, fluoride, dental enamel, demineralization, dental caries.
INTRODUCTION
In spite of the decline observed in dental caries, it still represents the most prevalent chronic childhood oral disease (Oral Health in America, 2000). In addition, the disease has become polarized, with carious surfaces being mostly in certain groups of children who present high caries activity (Tayanin et al., 2005). Consequently, the use of combined therapies for this population might be a promising method to prevent and control dental caries.
The efficacy of CO2 laser irradiation combined with fluoride in inhibiting enamel demineralization has been demonstrated by several laboratory investigations (Featherstone et al., 1991; Fox et al., 1992; Hsu et al., 1998; Hsu et al., 2001; Nobre dos Santos et al., 2001). However, there is no report about the in situ or in vivo caries-preventive effect of CO2 laser combined with fluoride dentifrice on dental enamel. Furthermore, no study has tested a transversely excited atmospheric pressure (TEA) CO2 laser operating at 9.6-µm wavelength combined with a fluoride dentifrice used under intra-oral conditions. It must be emphasized that the most efficient wavelengths for preventing dental caries are 9.3 and 9.6 µm, due to the high absorption coefficient in dental enamel at these wavelengths (Featherstone et al, 1998).
Thus, the objective of this study was to assess in situ the combined effects of...