Description:
<jats:title>Abstract</jats:title><jats:sec><jats:title>Aim</jats:title><jats:p>To investigate the chemical interaction of calcium hydroxide with the antibiotics demeclocycline calcium in <jats:styled-content style="fixed-case">L</jats:styled-content>edermix<jats:sup>®</jats:sup> Paste and clindamycin hydrochloride in <jats:styled-content style="fixed-case">O</jats:styled-content>dontopaste<jats:sup>®</jats:sup>.</jats:p></jats:sec><jats:sec><jats:title>Methodology</jats:title><jats:p>Validated methods were developed to analyse the interaction of calcium hydroxide in two forms, <jats:styled-content style="fixed-case">P</jats:styled-content>ulpdent<jats:sup>®</jats:sup> and calcium hydroxide powder, with the two antibiotics. High‐performance liquid chromatography (<jats:styled-content style="fixed-case">HPLC</jats:styled-content>) was used to analyse the mixed samples of the pastes and calcium hydroxide. The concentration of demeclocycline calcium over 0‐, 1‐, 18‐, 24‐, 72‐h and 7‐day time‐points was determined. The concentration of clindamycin hydrochloride over 1‐, 6‐, 24‐, 72‐h and 7‐day time‐points was determined. All tests with <jats:styled-content style="fixed-case">HPLC</jats:styled-content> involved testing of the standard in duplicate alongside the samples. Linearity, precision and specificity of the testing procedures and apparatus were validated. Descriptive statistics are provided.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>The antibiotics in both <jats:styled-content style="fixed-case">O</jats:styled-content>dontopaste<jats:sup>®</jats:sup> and <jats:styled-content style="fixed-case">L</jats:styled-content>edermix<jats:sup>®</jats:sup> Paste were affected by the addition of calcium hydroxide. When mixed with calcium hydroxide powder, <jats:styled-content style="fixed-case">O</jats:styled-content>dontopaste<jats:sup>®</jats:sup> had a 2% loss of clindamycin hydrochloride over 7 days, but when mixed with <jats:styled-content style="fixed-case">P</jats:styled-content>ulpdent<jats:sup>®</jats:sup>, there was a 36% loss over 7 days. <jats:styled-content style="fixed-case">L</jats:styled-content>edermix<jats:sup>®</jats:sup> Paste showed an 80% loss of demeclocycline calcium over 7 days when mixed with calcium hydroxide powder and a 19% loss when mixed with <jats:styled-content style="fixed-case">P</jats:styled-content>ulpdent<jats:sup>®</jats:sup> over the 7‐day period.</jats:p></jats:sec><jats:sec><jats:title>Conclusion</jats:title><jats:p>The addition of calcium hydroxide to <jats:styled-content style="fixed-case">O</jats:styled-content>dontopaste<jats:sup>®</jats:sup> or <jats:styled-content style="fixed-case">L</jats:styled-content>edermix<jats:sup>®</jats:sup> Paste results in reductions of the respective antibiotic over a 7‐day time period.</jats:p></jats:sec>