Sinc Interpolation implementation in Matlab for reconstructing or interpolating?
I haven't done this in MatLab, but have done it using C++. So I am not in a position to provide you any matlab code example or snippet, however I will direct you to some links that will help you clear your doubts and concepts regarding the sinc function, filtering and reconstruction.

Sinc function is basically used for low pass filtering signals and for reconstruction of the signal using the previous or old samples. Check out these links, It will clear your concepts about sinc function such as how its used for low pass filtering and reconstruction.

concept of sinc function :- http://www.dspguide.com/ch11/2.htm

Low pass filtering :- http://www.analog.com/media/en/technical-documentation/dsp-book/dsp_book_Ch16.pdf

Reconstruction is done through interpolation, check :- What is an algorithm to re-sample from a variable rate to a fixed rate?

There are already loads of discussion here about sinc functions, sinc windowing filters, interpolation techniques, reconstruction etc. Reading them will certainly help you clear your doubts and concepts regarding these. Hope this helps.