Laser Treatment Modulating Bacteria Ahesion To Human Enamel

Laser-induced prevention of enamel demineralization has been demonstrated in the past few decades. However, the potential effect of laser therapies on oral biofilm formation remains unknown. Objectives: This study was aimed to quantify the effect of laser on adhesion force of three oral pioneer bacteria to enamel using atomic force microscopy (AFM). Methods: Twenty-seven enamel slabs (3Χ2Χ2 mm) were cut from sound incisors and randomly assigned to the control and two experimental groups, laser-1 (L₁) and laser-2 (L₂), receiving 50Hz-300ms CO₂ laser treatments, with 10 μs & 200 μs respectively. S. oralis, S. mitis and S. sanguinis, were fixed with glutaraldehyde before transferred onto polyethyleneimine-coated cantilevers. A multimode AFM was employed to measure adhesion force between bacteria and enamel surfaces. Appropriate parametric/non-parametric analyses were performed to evaluate statistical significance of treatments on bacteria adhesion. Results: The adhesion forces of S. oralis was significantly decreased from 1113.1 (pN) to 587.3 (L₁) and 597.4 (L₂) with p=0.011 and p=0.010 respectively. The adhesion forces of S. sanguinis (p=0.060) and S. mitis (p=0.785) were decreased but not significantly affected by laser treatments. There is no difference between L₁ and l₂ treatment (all p>0.05).

Conclusions: Laser therapies may be promising in modulating adhesion of some oral bacteria and thus preventing oral biofilm formation for caries prevention.

(This study was finically supported by Singapore MOE grant R222-000-028-112)