Dear Arwa Saleh Bazighifan ,

You can use a chemical model to induce artificial caries-like lesions as the follow. "Placing each enamel sample in 32 mL of 50 mM buffer acetate solution (1.28 mmol/L Ca(NO3)2 ×4H2O, 0.74 mmol/L NaH2PO4 ×2H2O and 0.03 ppm F, pH 5.0) and kept at 37 °C incubator for 16 h."

- You can access this paper for further details.

Article pH-responsive Calcium and Phosphate-Ion Releasing antibacter...

Good luck!

Based on the information that you are investigating LDH inhibitors of S. mutans, I would assume that you are not interested in how to induce initial enamel caries lesions, but how to monitor lesion progression or assess lesion size. Correct? (you see it is not so easy to formulate a question in an unambiguous way).

The size of a lesion can be assessed for example by means of X-rays. In connection with caries experiments, for example, transverse microradiography (= TMR) is recommended as a well established method (de Josselin de Jong E, ten Bosch JJ, Noordman J: Optimised microcomputer-guided quantitative microradiography on dental mineral tissues slices. Phys Med Biol 1987;32:887-899).

TMR is replaced more and more with microct evaluations (see for example: Thomas, R., Ruben, J. L., De Vries, J., Ten Bosch, J. J., & Huysmans, M. C. D. N. J. M. (2006). Transversal wavelength-independent microradiography, a method for monitoring caries lesions over time, validated with transversal microradiography. Caries research, 40(4), 281-291).

Personally I prefer the microct approach, as you can perform repeated measurements with the same sample. It is a non-destructive method.

However, not everybody has such an expensive device.

Another well established alternative is quantitative light-induced fluorescence (QLF). You find plenty of publications on the website of www.inspektor.nl.

This publication might be especially interesting for you:

Kim, Y. S., Lee, E. S., Kwon, H. K., & Kim, B. I. (2014). Monitoring the maturation process of a dental microcosm biofilm using the Quantitative Light-induced Fluorescence-Digital (QLF-D). Journal of dentistry, 42(6), 691-696.

QLF does not need expensive equipment. You do not need the Inspector devices. You can do it yourself. You can for example use a fluorescence microscope. A simple FITC filter would be sufficient. QLF is valid only for lesions up to a thickness of 500 µm. But you will hardly every induce more tha 500 µm deep enamel lesions in the lab.

If you need software to evaluate your images, use ImageJ. I have written a plugin for ImageJ to perform QLF. Google will help you to find it.

I would go for the QLF in case you have budget restrictions.

If you have access to a microCT, go for the microCT method. But keep in mind. You can only see effects with are roughly 2.5 times the size of the so called voxel size. The explanation behind this is described here: https://en.wikipedia.org/wiki/Nyquist%E2%80%93Shannon_sampling_theorem

A lot of researchers using a microct does not know this limitation!

Sincerely

Karl-Heinz Kunzelmann

Demineralisation and remineralisation are surface phenomenon. There is no demineralisation of remineralisation in the body of the carious lesion. In the body of the lesion there is dissolution and recrystallisation.