ABSTRACT
<p><b>OBJECTIVE</b>To evaluate the effect of enamel matrix protein (EMP) on the attachment and proliferation of periodontal ligament cells (PDLC) on diseased cementum surfaces in vitro.</p><p><b>METHODS</b>Cementum chips were obtained from diseased roots exposed to periodontal pocket. Thirteen diseased root cementum chips were conditioned with EMP. Meanwhile, 13 diseased and 13 healthy cementum chips were treated with physiological saline as control. The growth and morphology of PDLC on the root surface were observed after 24 hours incubation by scanning electron microscope (SEM). PDLC attachment and proliferation were quantified using MTT assay at 16 or 72 hours.</p><p><b>RESULTS</b>The cells on EMP treated roots under SEM were growing robust like the cells on healthy roots. By contrast, the diseased cementum surface without conditioned with EMP was only partly covered with spindle-shaped cells, with filopodia appearing short and thin. MTT assay indicated that the number of adhered and proliferated cells on diseased cementum chips treated with EMP was significantly greater than that on diseased chips treated with saline (adhesion: 0.45 +/- 0.03 vs. 0.37 +/- 0.05, P < 0.05; proliferation: 0.71 +/- 0.02 vs. 0.55 +/- 0.08, P < 0.01), but less than that on healthy chips (adhesion: 0.45 +/- 0.03 vs. 0.67 +/- 0.08, P < 0.05; proliferation: 0.71 +/- 0.02 vs. 1.05 +/- 0.09, P < 0.05).</p><p><b>CONCLUSIONS</b>It was suggested that EMP could promote the growth of PDLC on the diseased root cementum surface.</p>