Method for producing a mockup of a patient's dental cosmetic restoration or a dental overlay device intended to be worn removably, characterized in that it comprises the following steps: - obtention of initial digital data representing at least part of the dentition having an initial aesthetic appearance; - at least partial virtual representation of the said dentition in its initial aesthetic appearance, on the basis of the initial data; - determination of the occlusion of the existing dentition and determination of a geometric limit such that the mockup or the dental overlay device has a minimal impact on the occlusion; - modification of the virtual aesthetic appearance of the teeth in order to obtain a modified aesthetic appearance; - forming a file of digital data representing the mockup of a dental cosmetic restoration or the dental overlay device, adapted to be placed in the mouth and worn temporarily over at least part of the existing dentition, - fabricating of the mockup or the dental overlay device directly from the file of digital data produced, said mockup or dental overlay device comprising at least one non-transparent anterior tooth face, intended to be superposed on the vestibular face of an existing tooth, to perform a cosmetic function, and said mockup or dental overlay device comprising the formation of at least one housing that at least partially conforms to the shape of an existing tooth so that the mockup can be clipped or inset onto the existing tooth, said mockup or dental overlay device being adapted to be clipped or inset to the dental arch without having a function of correcting malpositioning of the teeth, and the said mockup or dental overlay device having an anterior face comprising a thickness that is variable, and/or variable in all directions and/or having several anterior faces having mutually differing thicknesses to compensate for the deficiencies of the vestibular face of the existing teeth. - obtention of initial digital data representing at least part of the dentition having an initial aesthetic appearance; - at least partial virtual representation of the said dentition in its initial aesthetic appearance, on the basis of the initial data; - determination of the occlusion of the existing dentition and determination of a geometric limit such that the mockup or the dental overlay device has a minimal impact on the occlusion; - modification of the virtual aesthetic appearance of the teeth in order to obtain a modified aesthetic appearance; - forming a file of digital data representing the mockup of a dental cosmetic restoration or the dental overlay device, adapted to be placed in the mouth and worn temporarily over at least part of the existing dentition, - fabricating of the mockup or the dental overlay device directly from the file of digital data produced, said mockup or dental overlay device comprising at least one non-transparent anterior tooth face, intended to be superposed on the vestibular face of an existing tooth, to perform a cosmetic function, and said mockup or dental overlay device comprising the formation of at least one housing that at least partially conforms to the shape of an existing tooth so that the mockup can be clipped or inset onto the existing tooth, said mockup or dental overlay device being adapted to be clipped or inset to the dental arch without having a function of correcting malpositioning of the teeth, and the said mockup or dental overlay device having an anterior face comprising a thickness that is variable, and/or variable in all directions and/or having several anterior faces having mutually differing thicknesses to compensate for the deficiencies of the vestibular face of the existing teeth.