Combined effects of acidulated phosphate fluoride and argon laser on sound root surface morphology:: An in vitro scanning electron microscopy study

Objective: The purpose of this in vitro scanning electron microscopy (SEM) study was to evaluate the effects of combining low fluence argon laser (AL) irradiation and acidulated phosphate fluoride (APF) treatment on the surface morphology of sound human root surfaces. Summary Background Data: Previous in vitro investigations have shown that combined APF and AL irradiation of root surfaces provided a protective effect against cariogenic challenges, Materials and Methods: Twelve extracted human molars were sectioned into quarters, and each quarter assigned to 1 of 4 treatment groups: (1) no treatment/control; (2) low fluence (11.5 J/cm(2)) AL irradiation; (3) 1.23% APF for 4 minutes; (4) APF treatment followed by low fluence AL irradiation. Surface morphology alterations were compared among groups using SEM techniques. Results: AL irradiation alone produced irregular textured surfaces with adherent globular material and fine microporosities in the background. APF treatment, alternatively, only created relatively smooth surface coatings that masked the original underlying root surface. Combining APF treatment followed by AL irradiation resulted in a surface coating composed of relatively small (2 to 3 mu m) spherical to ovoid precipitates, morphologically resembling calcium fluoride. Conclusion: Combining APF with AL irradiation may create a more reactive surface that possesses fluoride-rich mineral deposits and protects the underlying root surface from cariogenic challenges.