Núbia Inocencya Pavesi Pini1, Débora Alves Nunes Leite Lima2, Benedikt Luka3, Carolina Ganss4, Nadine Schlueter5. 1. Department of Restorative Dentistry, Ingá University Center - Uningá, Road PR 317, 6114 - Parque Industrial 200, 87035-510, Maringá, Brazil; Department of Conservative and Preventive Dentistry, Dental Clinic, Justus Liebig University, Schlangenzahl Str. 14, D-35392, Giessen, Germany. Electronic address: prof.nubiapini@uninga.edu.br. 2. Department of Restorative Dentistry, Piracicaba Dental School, University of Campinas - FOP/Unicamp, P.O. BOX 52, 13414-903, Piracicaba, Brazil. 3. Division for Cariology, Department of Operative Dentistry and Periodontology, Center for Dental Medicine, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Hugstetter Str. 55, D-79106, Freiburg, Germany. 4. Department of Conservative and Preventive Dentistry, Dental Clinic, Justus Liebig University, Schlangenzahl Str. 14, D-35392, Giessen, Germany. 5. Division for Cariology, Department of Operative Dentistry and Periodontology, Center for Dental Medicine, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Hugstetter Str. 55, D-79106, Freiburg, Germany; Department of Conservative and Preventive Dentistry, Dental Clinic, Justus Liebig University, Schlangenzahl Str. 14, D-35392, Giessen, Germany.
Abstract
OBJECTIVES: Chitosan (Ch) in F/Sn-toothpastes can increase toothpastes' anti-erosive efficacy. Whether efficacy can be further increased by changing chitosan's viscosity was study aim. METHODS: 192 human enamel specimens were assigned to 2 × 6 groups (n = 16 each): Four F/Sn (500 ppm F-, 800 ppm Sn2+) toothpastes with chitosan (0.5 %, viscosity 50, 500, 1000 or 2000 mPas), negative-control (no F/Sn/chitosan), positive-control (F/Sn, no chitosan). The study was conducted in two experiments (E1/E2). Specimens were cyclically demineralised (10 d, 6 × 2 min/d; 0.5 % citric acid); half of groups (E1) was exposed to toothpaste slurries (2 × 2 min/d), the other half was additionally brushed (2 × 15 s/d, E2). Tissue loss (mean ± SD, μm) was quantified profilometrically. Element analysis (EDX, wt%) on specimen surfaces and on toothpastes' particulate fraction and SEM analysis of specimen surfaces were performed. RESULTS: Tissue loss in negative-controls (E1/E2) was 4.96 ± 1.55/12.76 ± 2.45. Toothpastes with active agents (AA) reduced tissue loss compared to negative-control (p < 0.0001). E1: All AA caused precipitates, being the thickest after Ch500. Chitosan increased carbon retention, not tin retention. E2: Only Ch1000 increased efficacy (-0.97 ± 4.48) compared to positive-control (2.98 ± 1.32; p = 0.05). EDX showed comparable carbon values in all AA; tin content was higher in Ch1000 (6.5 ± 3.4) compared to other AA (range: 3.8 ± 0.3-4.3 ± 1.3). On abrasives, tin adsorption was decreased by all chitosans. SEM revealed minor structural differences. CONCLUSIONS: Chitosan viscosity has impact on efficacy of F/Sn toothpastes. Under erosive/abrasive conditions Ch1000 showed the best protective effect with higher tin retention on surfaces and lower tin absorption by abrasives. CLINICAL SIGNIFICANCE: The biopolymer chitosan shows protective effect against enamel erosion and erosion/abrasion when used in an F/Sn toothpaste with specific viscosity.
OBJECTIVES: Chitosan (Ch) in F/Sn-toothpastes can increase toothpastes' anti-erosive efficacy. Whether efficacy can be further increased by changing chitosan's viscosity was study aim. METHODS: 192 human enamel specimens were assigned to 2 × 6 groups (n = 16 each): Four F/Sn (500 ppm F-, 800 ppm Sn2+) toothpastes with chitosan (0.5 %, viscosity 50, 500, 1000 or 2000 mPas), negative-control (no F/Sn/chitosan), positive-control (F/Sn, no chitosan). The study was conducted in two experiments (E1/E2). Specimens were cyclically demineralised (10 d, 6 × 2 min/d; 0.5 % citric acid); half of groups (E1) was exposed to toothpaste slurries (2 × 2 min/d), the other half was additionally brushed (2 × 15 s/d, E2). Tissue loss (mean ± SD, μm) was quantified profilometrically. Element analysis (EDX, wt%) on specimen surfaces and on toothpastes' particulate fraction and SEM analysis of specimen surfaces were performed. RESULTS: Tissue loss in negative-controls (E1/E2) was 4.96 ± 1.55/12.76 ± 2.45. Toothpastes with active agents (AA) reduced tissue loss compared to negative-control (p < 0.0001). E1: All AA caused precipitates, being the thickest after Ch500. Chitosan increased carbon retention, not tin retention. E2: Only Ch1000 increased efficacy (-0.97 ± 4.48) compared to positive-control (2.98 ± 1.32; p = 0.05). EDX showed comparable carbon values in all AA; tin content was higher in Ch1000 (6.5 ± 3.4) compared to other AA (range: 3.8 ± 0.3-4.3 ± 1.3). On abrasives, tin adsorption was decreased by all chitosans. SEM revealed minor structural differences. CONCLUSIONS: Chitosan viscosity has impact on efficacy of F/Sn toothpastes. Under erosive/abrasive conditions Ch1000 showed the best protective effect with higher tin retention on surfaces and lower tin absorption by abrasives. CLINICAL SIGNIFICANCE: The biopolymer chitosan shows protective effect against enamel erosion and erosion/abrasion when used in an F/Sn toothpaste with specific viscosity.