Periodontal instruments are designed for treating all types of gingival and periodontal diseases, such as scaling and root planing, curetting the gingiva or diseased tissue. Periodontal instruments are classified as periodontal probe, explorers, scaling, root planing and curettage instruments, and cleansing and polishing instruments. File scalers, chisel scalers, Gracey curettes, sickle scaler, sonic scaler, etc. are some of the instruments mentioned in this chapter. General principles of effective instrumentation are accessibility; visibility, illumination and retraction; condition of instruments; maintaining a clean field; instrument handling; and instrument adaptation. Tooth polishing is the act of smoothing the tooth surface so as to prevent the accumulation of plaque on the tooth surface area. Polishing methods, oral hygiene aids, toothbrushing techniques, oral hygiene methods, and oral prophylaxis are the topics discussed in this chapter.