- Browse by Subject
Browsing by Subject "bovine enamel"
Now showing 1 - 3 of 3
Results Per Page
Sort Options
Item Characteristics of Methylcellulose Acid Gel Lesions Created in Human and Bovine Enamel(Karger, 2013-01) Lippert, Frank; Butler, A.; Lynch, R. J. M.; Department of Cariology, Operative Dentistry and Dental Public Health, School of DentistryAcid gel caries lesions were created in 3,100 human and bovine enamel specimens and studied with transverse microradiography. Small, significant differences were found. Human enamel lesions were found to be less demineralized, shallower, had a higher ratio of integrated mineral loss (ΔZ) to lesion depth (L), a lower degree of surface zone mineralization (SZmax) and showed less variability than those in bovine enamel. SZmax showed the highest variability. Between tissues, L differed the most, ΔZ the least. Biological variation within bovine enamel is perhaps not only bigger than previously assumed, it may also overshadow any structural and chemical differences between tissues.Item Comparison of Human and Bovine Enamel in a Microbial Caries Model at Different Biofilm Maturations(Elsevier, 2020-05) Ayoub, Hadeel M.; Gregory, Richard L.; Tang, Qing; Lippert, Frank; Cariology, Operative Dentistry and Dental Public Health, School of DentistryObjectives 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).Item Comparison of Knoop and Vickers Surface Microhardness and Transverse Microradiography for the Study of Early Caries Lesion Formation in Human and Bovine Enamel(Elsevier, 2014-07) Lippert, Frank; Lynch, R. J. M.; Department of Cariology, Operative Dentistry and Dental Public Health, School of DentistryObjective The aims of the present laboratory study were twofold: a) to investigate the suitability of Knoop and Vickers surface microhardness (SMH) in comparison to transverse microradiography (TMR) to investigate early enamel caries lesion formation; b) to compare the kinetics of caries lesion initiation and progression between human and bovine enamel. Design Specimens (90 × bovine and 90 × human enamel) were divided into six groups (demineralization times of 8/16/24/32/40/48 h) of 15 per enamel type and demineralized using a partially saturated lactic acid solution. SMH was measured before and after demineralization and changes in indentation length (ΔIL) calculated. Lesions were characterized using TMR. Data were analyzed (two-way ANOVA) and Pearson correlation coefficients calculated. Results ΔIL increased with increasing demineralization times but plateaued after 40 h, whereas lesion depth (L) and integrated mineral loss (ΔZ) increased almost linearly throughout. No differences between Knoop and Vickers SMH in their ability to measure enamel demineralization were observed as both correlated strongly. Overall, ΔIL correlated strongly with ΔZ and L but only moderately with the degree of surface zone mineralization, whereas ΔZ and L correlated strongly. Bovine demineralized faster than human enamel (all techniques). Conclusions Lesions in bovine formed faster than in human enamel, although the resulting lesions were almost indistinguishable in their mineral distribution characteristics. Early caries lesion demineralization can be sufficiently studied by SMH, but its limitations on the assessment of the mineral status of more demineralized lesions must be considered. Ideally, complementary techniques to assess changes in both physical and chemical lesion characteristics would be employed.