RDA (Radioactive Dentin Abrasivity): This method is used to determine the abrasive level of dentifrices and abrasives, in human root dentin. The RDA value is calculated in relation to the abrasive level of a standard material (Ca2P2O7, Odontex Inc.), which is given the empirical value of 100. It involves the laboratorial procedure developed by Hefferren (1976) and recommended by the ADA and ISO 11609.
REA (Radioactive Enamel Abrasivity): This method is used to determine the abrasive level of dentifrices and abrasives, in human enamel. The REA value is calculated in relation to the abrasive level of a standard material (Ca2P2O7, Odontex Inc.), which is given the empirical value of 10. It is based on the laboratorial procedure developed by Hefferren (1976) and recommended by the ADA and ISO 11609.
PCR (Pellicle Cleaning Ratio): This test was developed in order to assess the ability of dentifrices to remove stained pellicle artificially created on enamel surfaces, i.e., to determine the cleaning ability of dentifrice formulations. The results of this test have shown to be comparable to those obtained in a clinical trial. Thus, they may be considered for the prediction of clinical findings with a reasonable degree of confidence. The PCR value is calculated relatively to a standard material (Ca2P2O7, Odontex Inc.), which is given the empirical value of 100.
EPP (Enamel Polishing Potential): This method is based on the work previously published by Bailey and Phillips (1950), on the study of abrasive prophylactic agents and techniques on enamel surfaces. Toothbrushing provides several benefits, including the polishing of enamel surfaces. Different toothpastes/abrasives may provide different polishing potential for enamel surfaces, and this can be determined by light reflection analysis. The outcome for this test is the difference in enamel gloss (or light reflection) between the pre- and post-treatment measurements.
Equipment: Toothbrush Machine
Model: Toothbrush-Dentifrice Assessment Instrument (TDA), Sabri Enterprises
Capabilities: This instrument has been modified to the study of power toothbrushes. It allows the study of the cleaning ability of electric and sonic toothbrushes in dental enamel previously stained.
Equipment: Scintillation Counter (2 units)
Model: TRI-CARB 1900TR, 2900TR, Packard
Capabilities: The counters are used to quantify the amount of radioactive phosphorus (32P) released from previously irradiated dental substrates. This procedure is done for the determination of the radioactive dentin abrasivity (RDA) and radioactive enamel abrasivity (REA) of dentifrices.
Equipment: Prophylaxis Testing Apparatus
Capabilities: This custom-made machine is used to test the abrasivity of dental prophylaxis pastes. It allows the contact between the prophy cup and the surface of experimental units, under standard conditions of force and time.
Model: CM2600d, Konica Minolta Spectrophotometer
Capabilities: Provides color coordinates L*a*b*, which represent the lightness of the color. This instrument has been used in experimental models testing the cleaning ability of dental products in enamel specimens previously stained.
Equipment: Brushing Machine (3 units)
Model: V-8, Brushing Machine/Custom-made
Capabilities: This brushing machine holds up to 8 experimental units at the same time and allows the study of the influence of brushing strokes, brushing force, type of toothbrush and type of dentifrice/slurry solution on the surface wear on dental substrates.