Root surface debridement – an in vitro assessment

Root planing has been advocated to render periodontally involved root surfaces 'biologically compatible' with the surrounding soft tissues and thus promote healing. However, recent work has shown that only small amounts of cytotoxic material are likely to be incorporated within the root surfaces, thereby questioning the rationale for the traditional emphasis that is placed upon the removal of 'diseased cementum'. This investigation assessed by limulus amoebocyte lysate (LAL) assay and Polymyxin B affinity chromatography the extent of residual lipopolysaccharide (LPS) following root surface instrumentation in vitro. A conservative regime was carried out, consisting of 15 instrument strokes per surface designed to ensure complete overlapping of the strokes. This harvested varying amounts of LPS from 18 single-rooted teeth while leaving behind less than 0.24 ng of LPS per tooth in the majority (72%) of cases. This finding endorses the growing belief that extensive root planing may not be warranted.