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The cumulative mercury intrusion volumes of the ReCaPP, PLGA-ReCaPP-40 and PLGA-ReCaPP-100 samples with aging times are shown in Fig. 3a. The total intrusion volumes for the PLGA-ReCaPP cements were always higher than the pure ReCaPP cements devoid of the PLGA KU57788 (without microspheres). The values of the total intrusion volumes for the ReCaPP cements did not change much with aging times (Fig. 3a–i); whereas for the PLGA-ReCaPP cements, the total intrusion volume increased slightly up to 15 days of aging (Fig. 3a-ii and iii). The total mercury intrusion volume however, increased considerably between 15 and 30 days of aging (Fig. 3a-ii and iii) and is likely consistent and attributable to the degradation of the PLGA microspheres. The pore size distributions of the ReCaPP cements with aging time demonstrate the presence of micropores in the 100 to 6 nm range and an absence of macropores in the 100 to 1 μm range (Fig. 3b-i). The PLGA-ReCaPP cements on the other hand, exhibited a bimodal distribution of the pore sizes after 30 days of aging, with the PLGA-ReCaPP-40 cements showing macropores in the 10–40 μm range and the PLGA-ReCaPP-100 cements showing macropores in the 10–100 μm range. In addition to large macropores there were minor contributions from the micropores in the 100–6 nm size range (Fig. 3b-ii and iii). Porosity data (different pore sizes intervals as well as the total porosity of the various samples) were produced using Eqs. (3) and (4) and are listed in Table S2 (see supplementary information). This Table shows that PLGA-ReCaPP cements exhibited much higher porosity values compared to ReCaPP cements following degradation of PLGA and the large porosities were in general due to pores in the range of 300–1 μm. There is an increase in the percentage porosity values (PHg) with aging times for both the PLGA-ReCaPP cements and pectin change is observed to be very high between 15 and 30 days of aging. These results thus indicate that most of the PLGA particles likely degrade between 15 and 30 days of aging and are consistent with the SEM results ( Fig. 1 and Fig. 2). The Table S2 (see supplementary information) also indicates that the non-porous ReCaPP cements contained mostly pores of diameter below 100 nm and PHg(%) values did not change much with aging time.