Apparatus for use in the fitting of dental prostheses; Apparatus for use in the preparation of dental prostheses; Dental apparatus and instruments; Dental moulding devices; Dental prostheses; Dental tools; Instruments for use in the fitting of dental protheses; Instruments for use in the fitting of orthodontic appliances; Instruments for use in the preparation of dental protheses; Instruments for use in the preparation of orthodontic appliances; Apparatus for use in orthodontics; Materials for use in orthodontics (prostheses); Orthodontic apparatus; Orthodontic appliances; Orthodontic products