A system (10, 2300) for surgical navigation in oral surgery, comprising: at least one processing system (30, 50, 2310) for: obtaining a three-dimensional anatomical representation (1910, 1965, 1970, 2010, 2110) of part of a patient; and producing at least one two-dimensional volume slice view (1920, 1930, 1940, 1975, 1980, 1985, 2020, 2030, 2040, 2120, 2130, 2140) of the three-dimensional anatomical representation (1910, 1965, 1970, 2010, 2110), the at least one two-dimensional volume slice view (1920, 1930, 1940, 1975, 1980, 1985, 2020, 2030, 2040, 2120, 2130, 2140) based on a physical position and axial orientation of at least one reference tool (26, 28, 800, 860, 870, 880, 1000); a display device (14, 58, 2320) for displaying the at least one two-dimensional volume slice view (1920, 1930, 1940, 1975, 1980, 1985, 2020, 2030, 2040, 2120, 2130, 2140) to a user; a tracking device (24, 2330) for recording the physical position and axial orientation of the at least one reference tool (26, 28, 800, 860, 870, 880, 1000) provided with one or more reference markers; wherein the at least one processing system (30, 50, 2310) is able to transform the physical position and axial orientation of the at least one reference tool (26, 28, 800, 860, 870, 880, 1000) into spatial coordinates relative to the three-dimensional anatomical representation (1910, 1965, 1970, 2010, 2110) of part of the patient; wherein, the at least one two-dimensional volume slice view (1920, 1930, 1940, 1975, 1980, 1985, 2020, 2030, 2040, 2120, 2130, 2140) to be displayed is updated by movement of the physical position and axial orientation of the at least one reference tool (26, 28, 800, 860, 870, 880, 1000) during surgical navigation in oral surgery; characterised by the at least one reference tool (26, 28, 800, 860, 870, 880, 1000) being a first reference tool (26, 1000) mounted on a piezo-electric surgical instrument (1010, 1040, 1780, 1880); and a drill tip (1005, 1050) mounted on the piezo-electric surgical instrument (1010, 1040, 1780, 1880); wherein in use the display device (14, 58, 2320) displays a real-time tracking view of the position and axial orientation of the drill tip (1005, 1050) of the piezo-electric surgical instrument (1010, 1040, 1780, 1880) relative to the three-dimensional anatomical representation (1910, 1965, 1970, 2010, 2110) and the at least one two-dimensional volume slice view (1920, 1930, 1940, 1975, 1980, 1985, 2020, 2030, 2040, 2120, 2130, 2140). at least one processing system (30, 50, 2310) for: obtaining a three-dimensional anatomical representation (1910, 1965, 1970, 2010, 2110) of part of a patient; and producing at least one two-dimensional volume slice view (1920, 1930, 1940, 1975, 1980, 1985, 2020, 2030, 2040, 2120, 2130, 2140) of the three-dimensional anatomical representation (1910, 1965, 1970, 2010, 2110), the at least one two-dimensional volume slice view (1920, 1930, 1940, 1975, 1980, 1985, 2020, 2030, 2040, 2120, 2130, 2140) based on a physical position and axial orientation of at least one reference tool (26, 28, 800, 860, 870, 880, 1000); obtaining a three-dimensional anatomical representation (1910, 1965, 1970, 2010, 2110) of part of a patient; and producing at least one two-dimensional volume slice view (1920, 1930, 1940, 1975, 1980, 1985, 2020, 2030, 2040, 2120, 2130, 2140) of the three-dimensional anatomical representation (1910, 1965, 1970, 2010, 2110), the at least one two-dimensional volume slice view (1920, 1930, 1940, 1975, 1980, 1985, 2020, 2030, 2040, 2120, 2130, 2140) based on a physical position and axial orientation of at least one reference tool (26, 28, 800, 860, 870, 880, 1000); a display device (14, 58, 2320) for displaying the at least one two-dimensional volume slice view (1920, 1930, 1940, 1975, 1980, 1985, 2020, 2030, 2040, 2120, 2130, 2140) to a user; a tracking device (24, 2330) for recording the physical position and axial orientation of the at least one reference tool (26, 28, 800, 860, 870, 880, 1000) provided with one or more reference markers; wherein the at least one processing system (30, 50, 2310) is able to transform the physical position and axial orientation of the at least one reference tool (26, 28, 800, 860, 870, 880, 1000) into spatial coordinates relative to the three-dimensional anatomical representation (1910, 1965, 1970, 2010, 2110) of part of the patient; wherein, the at least one two-dimensional volume slice view (1920, 1930, 1940, 1975, 1980, 1985, 2020, 2030, 2040, 2120, 2130, 2140) to be displayed is updated by movement of the physical position and axial orientation of the at least one reference tool (26, 28, 800, 860, 870, 880, 1000) during surgical navigation in oral surgery; characterised by the at least one reference tool (26, 28, 800, 860, 870, 880, 1000) being a first reference tool (26, 1000) mounted on a piezo-electric surgical instrument (1010, 1040, 1780, 1880); and a drill tip (1005, 1050) mounted on the piezo-electric surgical instrument (1010, 1040, 1780, 1880); wherein in use the display device (14, 58, 2320) displays a real-time tracking view of the position and axial orientation of the drill tip (1005, 1050) of the piezo-electric surgical instrument (1010, 1040, 1780, 1880) relative to the three-dimensional anatomical representation (1910, 1965, 1970, 2010, 2110) and the at least one two-dimensional volume slice view (1920, 1930, 1940, 1975, 1980, 1985, 2020, 2030, 2040, 2120, 2130, 2140).