This document summarizes a seminar on principles of periodontal instrumentation. It discusses key aspects of instrumentation including proper patient and operator positioning for accessibility, ensuring visibility and a clean field, using sharp instruments, stabilizing instruments through different grasps and fulcrums, and proper technique for instrument activation including blade adaptation, angulation, strokes, and pressure. The goal of instrumentation is to thoroughly remove calculus and produce a clean, biologically acceptable root surface to support periodontal health. Mastering the principles discussed is important for effective instrumentation.