Dampak Skeling dan Penghalusan Akar Gigi terhadap Ekspresi m-RNA Matrix Metalloproteinase-9, Proporsi Tannerella Forsythia, serta Penyembuhan Klinis pada Periodontitis Kronis = Scaling and Root Planing Effect to m-RNA Expression of Matrix Metalloproteinase-9, Proportion of Tannerella Forsythia, and Clinical Healing in Chronic Periodontitis.