Combined effects of acidulated phosphate fluoride and argon laser on soundroot 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 surfa ce morphology of sound human root surfaces. Summary Background Data: Previo us 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 trea tment/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. S urface morphology alterations were compared among groups using SEM techniqu es. 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 f ollowed by AL irradiation resulted in a surface coating composed of relativ ely small (2 to 3 mu m) spherical to ovoid precipitates, morphologically re sembling calcium fluoride. Conclusion: Combining APF with AL irradiation ma y create a more reactive surface that possesses fluoride-rich mineral depos its and protects the underlying root surface from cariogenic challenges.