Hadeel M Ayoub1, Richard L Gregory2, Qing Tang3, Frank Lippert4. 1. King Saud University, Dental Health Department, College of Applied Medical Sciences, P.O. Box 145111, Riyadh, 4545, Saudi Arabia; Indiana University, School of Medicine, Department of Family Medicine, Bowen Center for Health Workforce Research & Policy, 1110W. Michigan Street, Indianapolis, Indiana, 46202, USA. Electronic address: hayoub@iu.edu. 2. Indiana University, School of Dentistry, Department of Biomedical Sciences and Comprehensive Care, 1121W. Michigan Street, Indianapolis, Indiana, 46202, USA. Electronic address: rgregory@iu.edu. 3. Indiana University, School of Medicine, Department of Biostatistics, 410W. 10th Street, HITS 3000, Indianapolis, Indiana, 46202, USA. Electronic address: qingtang@iu.edu. 4. Indiana University, School of Dentistry, Department of Cariology, Operative Dentistry and Dental Public Health, 415 Lansing Street, Indianapolis, Indiana, 46202, USA. Electronic address: flippert@iu.edu.
Abstract
OBJECTIVES: To compare human versus bovine enamel when used in microbial caries models; and to evaluate the use of nylon mesh to support biofilm growth over enamel. METHODS: Twenty-four sub-subgroups were included (time factor: 4, 8, and 12 days; substrate factor: human/bovine; mesh factor: yes/no; treatment factor: 18.4 mM NaF (350 ppm F), de-ionized water [DIW]; n = 9/sub-subgroup). Microcosm biofilm from human saliva (IRB approval #1,406,440,799) was grown on enamel specimens for 24-h (Brain Heart Infusion media; 0.2 % sucrose), using active attachment model. Then, pH-cycling took place. At the end of each pH-cycling period, enamel specimens were analyzed: surface microhardness (VHNchange); transverse microradiography (integrated mineral loss [ΔZ], lesion depth [L]). Biofilm was analyzed: lactic acid production (LDH activity); exopolysaccharide (EPS) amount; and viability (12-day sub-groups). Data were analyzed using ANOVA at a 5 % level of significance. RESULTS: The three-way interaction between pH-cycling duration, substrate type, and treatment type was significant for (VHNchange [p < 0.0005], ΔZ [p = 0.0027], and L [p < 0.0001]). VHNchange exhibited increased lesion severity as pH-cycling time increases, in both treatments. VHNchange data indicated a treatment effect in all timepoints. ΔZ and L exhibited higher values with more mature biofilms. ANOVA analyses for LDH and EPS indicated a significance between variables (LDH p = 0.0100; EPS p < 0.0001). Mesh-covered specimens resulted in lower LDH and EPS values in all maturations. ANOVA analyses of viability (12 days) between variables was significant. CONCLUSION: within the study's limitations, human or bovine enamel can be used in microbial in vitro caries models to study biofilm's maturation and anticaries agents. CLINICAL SIGNIFICANCE: This study demonstrated how a known cariostatic effect of a fluoride concentration in toothpastes can be modulated by the maturation stage of oral biofilm. This can represent hard to reach areas in the oral cavity (e.g. in orthodontic patients or patients with intermaxillary fixation following oral and maxillofacial surgeries).
OBJECTIVES: To compare human versus bovine enamel when used in microbial caries models; and to evaluate the use of nylon mesh to support biofilm growth over enamel. METHODS: Twenty-four sub-subgroups were included (time factor: 4, 8, and 12 days; substrate factor: human/bovine; mesh factor: yes/no; treatment factor: 18.4 mM NaF (350 ppm F), de-ionized water [DIW]; n = 9/sub-subgroup). Microcosm biofilm from human saliva (IRB approval #1,406,440,799) was grown on enamel specimens for 24-h (Brain Heart Infusion media; 0.2 % sucrose), using active attachment model. Then, pH-cycling took place. At the end of each pH-cycling period, enamel specimens were analyzed: surface microhardness (VHNchange); transverse microradiography (integrated mineral loss [ΔZ], lesion depth [L]). Biofilm was analyzed: lactic acid production (LDH activity); exopolysaccharide (EPS) amount; and viability (12-day sub-groups). Data were analyzed using ANOVA at a 5 % level of significance. RESULTS: The three-way interaction between pH-cycling duration, substrate type, and treatment type was significant for (VHNchange [p < 0.0005], ΔZ [p = 0.0027], and L [p < 0.0001]). VHNchange exhibited increased lesion severity as pH-cycling time increases, in both treatments. VHNchange data indicated a treatment effect in all timepoints. ΔZ and L exhibited higher values with more mature biofilms. ANOVA analyses for LDH and EPS indicated a significance between variables (LDH p = 0.0100; EPS p < 0.0001). Mesh-covered specimens resulted in lower LDH and EPS values in all maturations. ANOVA analyses of viability (12 days) between variables was significant. CONCLUSION: within the study's limitations, human or bovine enamel can be used in microbial in vitro caries models to study biofilm's maturation and anticaries agents. CLINICAL SIGNIFICANCE: This study demonstrated how a known cariostatic effect of a fluoride concentration in toothpastes can be modulated by the maturation stage of oral biofilm. This can represent hard to reach areas in the oral cavity (e.g. in orthodontic patients or patients with intermaxillary fixation following oral and maxillofacial surgeries).
Authors: Aline S Letieri; Liana B Freitas-Fernandes; Ivete P R Souza; Ana P Valente; Tatiana K S Fidalgo Journal: Curr Microbiol Date: 2022-02-07 Impact factor: 2.188
Authors: Johannes Mischo; Thomas Faidt; Ryan B McMillan; Johanna Dudek; Gubesh Gunaratnam; Pardis Bayenat; Anne Holtsch; Christian Spengler; Frank Müller; Hendrik Hähl; Markus Bischoff; Matthias Hannig; Karin Jacobs Journal: ACS Biomater Sci Eng Date: 2022-03-09