A method of generating a model of a real jaw derived from a model jaw, the model jaw being defined by an array of data points, a number of teeth and a number of further teeth, the further teeth corresponding to missing teeth, the method comprising: measuring a number of parameters of a number of teeth of the real jaw, the real jaw having a curved jaw line, the number of parameters corresponding to a number of teeth in the model jaw; generating an array of data points defining a first model of the real jaw using a number of the measured parameters; and generating a further model of the real jaw, the step of generating the further model comprising the steps of: aligning the model jaw with the first model of the real jaw; placing a number of teeth represented in the model jaw into positions corresponding to positions of equivalent teeth in the real jaw as defined by the measured parameters; placing a number of the further teeth represented in the model jaw into positions on the first model of the real jaw to represent corresponding teeth in the real jaw; and adjusting the positions of one or more of the teeth placed on the first model of the real jaw to generate the further model of the real jaw, wherein the step of measuring comprises measuring the parameters using a sensor comprising a six degrees of freedom probe connected to a processor configured to process data received from the sensor, and wherein the step of generating an array of data points defining a first model of the real jaw comprises creating an array of data points defining a first datum line curve corresponding to a curved shape of the real jaw, and the position of each tooth is described by only one parameter which represents the distance along the datum line curve. measuring a number of parameters of a number of teeth of the real jaw, the real jaw having a curved jaw line, the number of parameters corresponding to a number of teeth in the model jaw; generating an array of data points defining a first model of the real jaw using a number of the measured parameters; and generating a further model of the real jaw, the step of generating the further model comprising the steps of: aligning the model jaw with the first model of the real jaw; placing a number of teeth represented in the model jaw into positions corresponding to positions of equivalent teeth in the real jaw as defined by the measured parameters; placing a number of the further teeth represented in the model jaw into positions on the first model of the real jaw to represent corresponding teeth in the real jaw; and adjusting the positions of one or more of the teeth placed on the first model of the real jaw to generate the further model of the real jaw, aligning the model jaw with the first model of the real jaw; placing a number of teeth represented in the model jaw into positions corresponding to positions of equivalent teeth in the real jaw as defined by the measured parameters; placing a number of the further teeth represented in the model jaw into positions on the first model of the real jaw to represent corresponding teeth in the real jaw; and adjusting the positions of one or more of the teeth placed on the first model of the real jaw to generate the further model of the real jaw, wherein the step of measuring comprises measuring the parameters using a sensor comprising a six degrees of freedom probe connected to a processor configured to process data received from the sensor, and wherein the step of generating an array of data points defining a first model of the real jaw comprises creating an array of data points defining a first datum line curve corresponding to a curved shape of the real jaw, and the position of each tooth is described by only one parameter which represents the distance along the datum line curve.