A modified pH-cycling model to evaluate fluoride effect on enamel demineralization

This study evaluated the effect of a 2% chlorhexidine-based disinfectant (CHX) on the short-term resin-dentin bond strength of a self-etch adhesive system to human dentin with different mineral contents. Dentinal mineralization was tested at 4 levels (sound, and after 2, 4, or 8 days of demineralization-remineralization cycles) and disinfectant at 2 levels [deionized water (DW, negative control) and CHX]. Dentin demineralization induced by pH-cycling was characterized by crosssectional hardness (CSH). Each dentin surface was divided into halves, one treated with DW and the other with CHX (5 minutes). Each surface was bonded with a self-etch adhesive system and restored. The specimens were sectioned and subjected to microtensile bond testing. CSH and microtensile bond strength (µTBS) data were analyzed by regression analysis and ANOVA-Tukey tests (α = 5%), respectively. The groups treated with CHX resulted in mean µTBS similar to those found for the groups in which the dentin was exposed to DW (p = 0.821). However, mean µTBS were strongly influenced by dentin mineralization (p < 0.05): the bond strength found for sound dentin was lower than that found for dentin cycled for 8 days, which was even lower than the bond strengths for dentin cycled for 2 or 4 days. The results suggest that the degree of dentin demineralization affects the bond strength of self-etching adhesives, but the use of CHX does not modify this effect.

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“…When the hardness differences in each studied depth from the surface were com-0.050 ppm F, and 0.15 M KCl adjusted to a pH of 7.4. 14 …”

Section: Resultsmentioning

confidence: 99%

Effect of chlorhexidine on the bond strength of a self-etch adhesive system to sound and demineralized dentin

et al. 2013

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“…This cycling model simulates the variation in pH that occurs in the oral environment in patients with deficient oral hygiene and favors the development of caries lesions. 12,13,19,20 In these patients, there is also increased susceptibility to corrosion since the accumulation of acidogenic microorganisms around the bracket favors its biodegradation. 4,7,16,17,21 The atomic absorption spectrophotometry findings demonstrated that the concentration of nickel, chromium, and iron in the tooth fragments of the group with corrosion and cycling was higher than that found in both the control group and the group in which there were only demineralization and remineralization cycles (Table 5).…”

Section: Discussionmentioning

confidence: 99%

“…After the eighth cycle, the test specimens remained in the remineralizing solution for another 24 hours until the analyses were performed. 13 The group Corrosion + DesRe was also submitted to the same cycling process as group DesRe. In this group, however, 7 days before cycling began, orthodontic stainless-steel brackets, bands, tubes, and wires were added to each receptacle containing the demineralizing and remineralizing solutions, to simulate standard orthodontic appliances in mandibular and maxillary arches ( Table 4).…”

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confidence: 99%

Incorporation of metal and color alteration of enamel in the presence of orthodontic appliances

Maia

Filho

Araújo

et al. 2012

The Angle Orthodontist

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Objective: To test the null hypothesis that it is not possible to incorporate metal ions arising from orthodontic appliance corrosion into tooth enamel with resulting tooth color change. Materials and Methods: This in vitro study used atomic absorption spectrophotometry to evaluate the presence of nickel, chromium, and iron ions in tooth enamel in three groups: a group submitted to cyclic demineralization and remineralization processes with solutions in which orthodontic appliances were previously immersed and corroded, releasing metallic ions; a control group; and another group, submitted to cycling only, without the presence of orthodontic appliances. The influence of the incorporation of these metals on a possible alteration in color was measured with a portable digital spectrophotometer using the CIE LAB system. Results: At the end of the experiment, a significantly higher concentration of chromium and nickel (P , .05) was found in the group in which corrosion was present, and in this group, there was significantly greater color alteration (P # .001).Conclusions: There was chromium and nickel incorporation into enamel and tooth color change when corrosion of orthodontic appliances was associated with cycling process. The null hypothesis is rejected. (Angle Orthod. 2012;82:889-893.)

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“…On the fourth day of the cycle, the solutions were replaced. After the eighth day of the cycle, the samples were put in fresh remineralizing solution for 24 hours 13 .…”

Section: Methodsmentioning

confidence: 99%

Effectiveness of different removal methods of artificially demineralized dentin

et al. 2016

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Objective: This study aimed to evaluate the effectiveness of different mechanical methods for the removal of demineralized dentin. Methods: Healthy human third molars were prepared in such a way that the flat occlusal surfaces of the dentin were exposed and longitudinally sectioned in a vestibular-lingual direction. One section of each tooth was submitted to the pH-cycling model, while the other section was kept intact. The tooth sections were joined, and a single operator performed dentin removal using a steel bur, a hand instrument, or a polymer bur. The tooth's sections were then separated, and digital images were obtained. The depth of the prepared cavities and the microhardness measurements were checked and analyzed statistically using the Kruskal-Wallis One-Way ANOVA in Ranks, the Tukey test, while desmineralized dentin were compared using the One-Way ANOVA, and the Holm-Sidak method (p < 0.05). Results: The steel bur produced the deepest cavities in mineralized and demineralized dentin. The polymer bur generated the shallowest cavities in demineralized dentin. The measurements of microhardness of the deepest surfaces of the cavities prepared in demineralized dentin indicated that the steel bur and hand instrument presented similar values, while those values produced by polymer burs proved to be lower. Conclusion: The effectiveness of the removal of demineralized dentin varied among the three methods used in this study. The polymer bur proved to be the most conservative of the methods used. By contrast, the steel bur and hand instrument showed a similar effectiveness in the removal of dentin, according to the microhardness of the remaining dentin, even though they produced different cavity depths.

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A modified pH-cycling model to evaluate fluoride effect on enamel demineralization

Cited by 98 publications

References 19 publications

Effect of chlorhexidine on the bond strength of a self-etch adhesive system to sound and demineralized dentin

Effect of chlorhexidine on the bond strength of a self-etch adhesive system to sound and demineralized dentin

Incorporation of metal and color alteration of enamel in the presence of orthodontic appliances

Effectiveness of different removal methods of artificially demineralized dentin

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