Fluoride And Non-Fluoride Polishing System: Comparative Evaluation

OBJECTIVES: Aim of this investigation was to evaluate the effectiveness of a new rubber tip polishing system containing sodium fluoride (Pasteless Prophy®, Kerr) compared with a non-fluoride rubber tip system. METHODS: 15 extracted teeth, caries-free, stored in physiological solution, were prepared with one box on the vestibular surface, one on the palatal/lingual surface. Restorations were performed using an Etch & Rinse adhesive followed by a nanohybrid resin-composite. After finishing the restorations using a diamond burr, polishing of the vestibular surfaces was performed using fluoride (NaF) rubber tips (test), whereas the lingual/palatal side was polished using standard non-fluoride rubber tips (control). Samples were scraped off on both surfaces with abrasive paper transparent in the infrared; the obtained dust, mixed with potassium bromide and pressed to obtain glass-based disks, was analyzed with a Perkin Elmer Spectrum GX1 spectrometer. For data handling Spectrum v.6.3.1 and Grams AI 7.02 software packages were used. RESULTS: The results showed that samples treated with NaF rubber tip were always more crystalline than controls. These data revealed that the fluoride contained in the rubber tip and the salivary acidity might increase surface crystallization, enabling links between fluoride ions and the substrate. The quantification of the fluoride contribution, given by the NaF rubber tip, was achieved by means of the peak fitting procedure, evaluating the intensity absorbance band ratio between the vibrational mode at 1096 cm-1 (marker of the HA crystalline structure) and the one at 1031 cm-1 (arising from amorphous HA), thus obtaining an increase of crystallization percentage between 6 and 55. CONCLUSIONS: The spectral results demonstrate the effectiveness of the polishing system. More investigations are required to better understand the mechanism of action of NaF. Anyhow this study shows the potentiality of infrared spectroscopy in revealing modifications of composition, structure and morphology of clinically relevant materials.