Dental compositions are described which are photocurable by radiation with a wavelength greater than 390 nm. A pressing ring 23 is held at the advance position together with an operation sleeve 22 by a guide washer 24 forced by a coil spring 25. The arm is generally is free to rotate within the sleeve about a first axis defined by length of the arm. The similarity between the partial pattern of the model registered in the search place on the table and the partial pattern of the recognition object is judged; and a plurality of hypothesis information showing that the recognition object exists in the image is generated based on the similarity between both partial patterns. All the spring arms can mechanically and electrically connect with the inserted electronic card reliably and perform ESD function. The apparatus is a specially designed fatigue gauge that contains breakable ligaments of either variable length to measure fatigue strength or fatigue damage of metallic, polymeric and composite materials or the same length but different composition to measure the fatigue strength and fatigue damage of certain composite materials.