Effect of 10% fluoride on the remineralization of dentin in situ

Thymol as adjuvant in oncology: molecular mechanisms, therapeutic potentials, and prospects for integration in cancer management

Cancer remains a global health challenge, prompting a search for effective treatments with fewer side effects. Thymol, a natural monoterpenoid phenol derived primarily from thyme (Thymus vulgaris) and other plants in the Lamiaceae family, is known for its diverse biological activities. It emerges as a promising candidate in cancer prevention and therapy. This study aims to consolidate current research on thymol's anticancer effects, elucidating its mechanisms and potential to enhance standard chemotherapy, and to identify gaps for future research. A comprehensive review was conducted using databases like PubMed/MedLine, Google Scholar, and ScienceDirect, focusing on studies from the last 6 years. All cancer types were included, assessing thymol's impact in both cell-based (in vitro) and animal (in vivo) studies. Thymol has been shown to induce programmed cell death (apoptosis), halt the cell division cycle (cell cycle arrest), and inhibit cancer spread (metastasis) through modulation of critical signaling pathways, including phosphoinositide 3-kinase (PI3K), protein kinase B (AKT), extracellular signal-regulated kinase (ERK), mechanistic target of rapamycin (mTOR), and Wnt/β-catenin. It also enhances the efficacy of 5-fluorouracil (5-FU) in colorectal cancer treatments. Thymol's broad-spectrum anticancer activities and non-toxic profile to normal cells underscore its potential as an adjunct in cancer therapy. Further clinical trials are essential to fully understand its therapeutic benefits and integration into existing treatment protocols.

A Comparison of the Fluoride 'Paint- On' vs Tray Application Techniques for Enamel Remineralisation

BACKGROUND

Fluoride gel treatment is not recommended for children < 6 years old due to its potential toxicity. Hence the aim of this study was to compare the effect of 1.23% acidulated-phosphate fluoride (APF) gel paint-on and the conventional tray application techniques on artificial, deciduous enamel carious lesions embedded on wearable appliances.

METHODS

In a randomised crossover study, the volunteer children (n = 29) wore mandibular removable appliances containing embedded tooth specimens with artificial carious lesions. The volunteers had 3 different treatment protocols: (I) 0.4 mL non-fluoride (control) gel, (II) 0.4 mL paint-on 1.23% APF gel or (III) 5 mL 1.23% APF gel, 4 minutes tray application. After 1 hour, the appliances were removed and the specimens underwent an in vitro, 14 days of pH-cycling. The mean percentage reduction in fluorescence (ΔF, %) at baseline (ΔF0) and after the pH-cycling (ΔF1) were determined using quantitative light-induced fluorescence-digital analysis. The mean ΔΔF (ΔF1-ΔF0) was calculated to compare the differences between groups.

RESULTS

The mean ΔΔF of groups I to III were -1.42 ± 1.49, 1.06 ± 2.11, and 1.12 ± 3.57 and -1.25 ± 1.44, 1.13 ± 1.84 and 1.44 ± 3.62 for the smooth surface and proximal surface lesions, respectively. The mean ΔΔF in the 2 treatment groups were significantly greater compared with the control group (P < .001). There was no significant difference in ΔΔF between the APF gel tray and paint-on groups either in the smooth surfaces, or the proximal surfaces (P = .629 and P = .613, respectively).

CONCLUSION

Our study, for the first time, indicates that the paint-on application of APF gel or the tray application of APF had a similar enamel remineralisation effect. Clinically, this implies that, particularly in younger children, the paint-on application of fluoride is less cumbersome, and possibly more tolerable with a lesser likelihood of fluoride ingestion than the tray application technique.

TRIAL REGISTRATION

Thai Clinical Trial Registry (https://www.thaiclinicaltrials.org/show/TCTR20190724001).

Functional role of inorganic trace elements in dentin apatite tissue-part III: Se, F, Ag, and B

Dentin hydroxyapatite possesses a unique versatile structure which allows it to undergo ionic substitutions. Trace elements play pivotal roles within the oral cavity, especially in dentin apatite tissue. Therefore, it is critical to explore the role of these elements in dentin apatite structure. The roles of other inorganic elements in dentin apatite were discussed in part I (Mg, Sr, Zn, and Fe) and part II (Cu, Mn, Si, and Li) of these series. In the last part of the review series, the role of selenium, fluorine, silver, and boron in the regulation of dentin apatite structure and function was discussed. We evaluated how these elements affect the overall size, morphology, and crystallinity of dentin apatite crystals. Moreover, we investigated the importance of these elements in regulating the solubility of dentin apatite. An electronic search was performed on the role of these trace elements in dentin apatite from January 2010 to January 2022. The concentration of selenium in teeth has been explored only recently, particularly its incorporation into dentin apatite. Silver nanomaterials inhibit the growth of cariogenic microorganisms as well as arrest the degradation of collagen. Fluorine was found to have important roles in dentin remineralization and dentinal tubule occlusion, making it widely used for hydroxyapatite doping. Boron is critical for mineralized tissues like bone, dentin, and enamel, but its exact role in dentin apatite is unknown. Therefore, understanding the impact of these elements on dentin apatite is potentially transformative, as it may help to fill a significant knowledge gap in teeth mechanics.