Brenda Maggio

Clinical study investigating abrasive effects of three toothpastes and water in an in situ model

OBJECTIVES This in situ study compared the abrasive effect of repeated brushings (over 10 days) of a low relative abrasive dentine (RDA) toothpaste with moderate and high relative abrasive dentine (RDA) toothpastes, on human dentine in situ. MATERIALS AND METHODS The study design was single centre, single blind, randomized, split mouth, two period, four-treatment cross-over, in situ study in 20 healthy subjects. Subjects wore bi-lateral lower buccal appliances each fitted with four dentine sections with treatment applied with a power toothbrush, during each 10 day study period. Samples were measured at baseline, day 5 and day 10 by contact profilometry, and baseline and day 10 with non-contact profilometry. RESULTS Nineteen subjects were included in the efficacy analysis. Results as measured by contact and non-contact profilometry from brushing with the moderate RDA paste and high RDA paste showed significantly (p<0.0001) more abrasion to dentine than brushing with the low RDA paste or water after 10 days. Dentine loss following tooth brushing with the low RDA paste was not significantly different from brushing with water, after 10 days. CONCLUSIONS The methodology successfully showed clear differentiation between the amount of dentine lost following toothbrushing with the low RDA paste compared to the moderate or high RDA pastes. Dentine loss following brushing with the low RDA paste showed a comparable degree of abrasion to brushing with water.

Evaluation of mouthrinse and dentifrice regimens in an in situ erosion remineralisation model

OBJECTIVES To compare the effectiveness of dentifrice/mouthrinse regimens in a clinical in situ erosion remineralisation model. METHODS Thirty-six subjects completed a randomised single-blind cross-over trial of five treatment regimens. R1: Dentifrice A [1450 ppm fluoride as the sodium salt (NaF), 50000 ppm potassium nitrate (KNO(3))] plus 450 ppm fluoride (NaF) rinse; R2: Dentifrice A plus sterile water rinse; R3: Dentifrice B (fluoride-free Dentifrice A) plus sterile water rinse; R4: Dentifrice B plus 450 ppm fluoride (NaF) rinse; R5: Dentifrice C (1000 ppm fluorine as sodium monofluorophosphate, 450 ppm fluoride as NaF) plus sterile water rinse. Subjects wore a palatal appliance holding eight pre-demineralised enamel blocks. A 60 min interval separated in vivo use of dentifrice and rinse with the appliance retained in situ for 4h. Efficacy endpoints were percentage surface microhardness recovery (%SMHR) following remineralisation, and percentage relative erosion resistance (%RER) of recovered specimens following a subsequent in vitro erosive challenge. Statistical analyses included ANOVA and selected twin-tailed t-tests. RESULTS Mean %SMHR (±SE) was (a)42.14±1.39, (b)38.02±1.39, (c)30.57±1.39, (b)37.75±1.39 and (c)30.88±1.39 for regimens R1-R5 respectively (different superscripts denote statistically significant differences (p<0.05) between treatment regimens). Mean %RER (±SE) was (a)-2.88±2.16, (b)-14.54±2.16, (c)-40.05±2.16, (a)-3.76±2.16 and (d)-29.48±2.16 for regimens R1-R5 respectively. R1 elicited statistically significantly greater %SMHR versus all comparator regimens (p<0.01), and conferred statistically significantly greater %RER than comparator regimens (p<0.0001) except R4 (p=0.70). CONCLUSIONS The combination treatment of dentifrice A containing 1450 ppm fluoride with the 450 ppm fluoride mouthrinse elicited significant enhancements in rehardening of incipient enamel erosive lesions, and significantly increased their subsequent resistance to a second erosive challenge.