pd4dSize: PD4D Endo scaling tip can be autoclaved between 5-20 minutes at 134°C The PD4D are used to remove subgingival calculus and interdental calculus.The PD3DPD4D scaler tips are compatible with their DTE scaler handpieces and NSK orinal. PD3D: Used to level off the surface of endo during periodontal flap