and covers having {HEAD ~ perimetric depressions} for fitting {TAIL ~ the covers} to said prism boxes, such that when said covers are removed it is possible to reach through said prism boxes for fixing the edges of the orthodontic models positioned between said prism boxes 
and covers having { HEAD ~ perimetric depressions } for fitting { TAIL ~ the covers } to said prism boxes , such that when said covers are removed it is possible to reach through said prism boxes for fixing the edges of the orthodontic models positioned between said prism boxes
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH