1. Gagging Severity Index (GSI).

Severity grading	Description
Grade I Normal gagging reflex	Very occasional gagging occurs during high‐risk dental procedures such as maxillary impression taking or restoration to the distal, palatal or lingual surfaces of molar teeth. This is basically a 'normal' gag reflex under difficult treatment circumstances. Generally controlled by the patient
Grade II Mild gagging	Gagging occurs occasionally during routine dental procedures such as fillings, scaling and impressions. Control can usually be regained by the patient, although they may need assistance and reassurance from members of the dental team, and treatment continued. No special measures are generally needed to facilitate routine treatment but may be required for more difficult procedures
Grade III Moderate gagging	Gagging occurs routinely during normal dental procedures. This may include simple physical examination of high‐risk areas such as the lingual aspect of lower molars. Once instigated, control is difficult to regain without cessation of the procedure. Re‐commencement may be difficult. Gagging prevention measures are usually required. The gag may influence treatment planning and may limit treatment options
Grade IV Severe gagging	Gagging occurs with all forms of dental treatment including simple visual examination. Routine treatment is impossible without some form of special measure to attempt to control the gag reflex. Treatment options may be limited and the gagging problem will be a major factor in treatment planning
Grade V Very severe gagging	Gagging occurs easily and may not necessarily require physical intervention to trigger the reflex. The patient's behaviour and dental attendance may be governed by the gagging problem and it will be one of the prime factors when planning treatment. Treatment options may be severely limited. Dental treatment will be impossible to carry out without specific, special treatment for control of the gagging problem

Quoted from Rosted 2006.