The characteristic features of the design lie in the shape and configuration of a dental block holder as shown in the drawings; the parts shown by means of broken lines in the reproductions are not part of the claimed design; the dashed-dotted lines represent a boundary between a part of the claimed design and apart other than the part of the claimed design; Reproductions 1.8, 2.8, 3.8, 4.8, 5.8, 6.8 and 7.8 are cross-sectional views along line A-A in Reproductions 1.2, 2.2, 3.2, 4.2, 5.2, 6.2 and 7.2 respectively; Reproductions 1.9, 2.9, 3.9, 4.9, 5.9, 6.9 and 7.9 are cross-sectional views along line B-B in Reproductions 1.2, 2.2, 3.2, 4.2, 5.2, 6.2 and 7.2 respectively;
Reproduction 3.10 is a cross-sectional view along line C-C in
Reproduction 3.2; the thin lines represent in Reproductions 1.1, 1.2, 1.10, 2.1, 2.2, 2.10, 3.1, 3.2, 3.11, 4.10, 5.10, 6.10 and 7.10 are to identify the shape of the three-dimensional surface; Reproductions 1.10, 2.10, 3.11, 4.10, 5.10, 6.10 and 7.10 are reference views showing the condition in use and are not part of the claimed design; In Reproductions 1.10, 2.10, 3.11, 4.10, 5.10, 6.10 and 7.10 respectively, a block portion is shown on the left side; the dental block holder is attached to a
dental prosthesis fabrication device with the block portion fixed thereto to make a
dental prosthesis.