The ornamental design for a case for aligner or retainer, as shown and described.
FIG. 1 is a perspective view of a case for aligner or retainer showing my new design;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a left side view thereof;
FIG. 5 is a right side view thereof;
FIG. 6 is a top view thereof;
FIG. 7 is a bottom view thereof;
FIG. 8 is a cross-sectional view taken along line 8-8 in FIG. 2; and,
FIG. 9 is a perspective view thereof, shown in an alternate state.
The ornamental design which is claimed is shown in the drawings as solid lines and surfaces having surface shading. The broken lines shown in FIGS. 8 and 9 illustrate portions of the case for aligner or retainer that form no part of the claimed design.