Enamel Birefringence Interpretator (EBI, v 0.1): a freeware to interpret enamel birefringence

   The mathematical approach used to interpret enamel birefringence (Sousa et al., J Microsc, 2006) can now be applied with the software Enamel Birefringence Interpretator (EBI v.0.1), developed by Gonzaga Y. and Sousa F.B., available for free download here:

https://drive.google.com/drive/folders/1T6jK8vd5dxB1wrFn3B1AEvClFLNCVCot

  Once downloaded, double click opens the following window:

  There are two columns, each one with four empty boxes. Mineral volume fraction (based on a  mineral density of 2.99 gcm-3) and the value of observed birefringence (BRobs) in water are the minimum data required to obtain an interpretation. This later means that data on water and organic volume fraction will be obtained. The data of the study of Angmar et al (1963), published in a recent post in this blog, will be used as an example. Taking data of the point located at 100 microns from the enable surface of tooth a, it is possible to convert mineral volume fraction to the value based on a mineral density of 2.99 gcm-3 using Eq. (1) published in the same post. The result is a mineral volume fraction of 0.9234 (92.34%). The corresponding BRobs value in water is (-) 0.002 (insert as -20; see that the box is multiplied by 1E-4) and in air is (-)0.001875 (insert as -18.75). Ten click "Calculate". The following result will appear.

  The results show the non-mineral volume fraction (V2) and the organic (beta), water (alfa), firmly bound water (alfa 1) and loosely bound water (alfa 2) volume fractions. It is now easier to implement the interpretation of enamel birefringence. The reader is now able, for example, to quantify the water and organic volumes of artificial enamel caries from Theuns et al (Caries Res, 1993) and to compare result with predicted values according to Sousa et al (J Microsc, 2009). The differences between experimental and predicted values of water volume can be compared with data published in Fig. 4 of Sousa et al. (Caries Res, 2013). 

  NOTE: mineral volume should be based on a mineral density of 2.99 gcm-3 (see Elliott JC. Structure, crystal chemistry and density of enamel apatites; in Chadwick D, Cardew G (eds): Dental Enamel. Ciba Foundation Symposium 205. Wiley, Chichester, 1997, pp 54–72).