The software that created those files is some version of Dentofacial Planner or Dentofacial Planner Plus. The last version released seems to be Dentofacial Planner Plus 8.0 beta. Their website is http://www.dentofacial.com.
Using the Internet Wayback Machine I got the free version of Dentofacial Showcase 2.0, which includes a file named "Sample.sd". The strings you mentioned appear in the sample file, although with different (older) versions.
About opening the files nowadays, your best bet would be finding a copy of the software (Dentofacial Showcase should work too) of a version equal or greater than that which created the original files and running it on Windows XP. It may have an option to export to standard formats or to documented file formats.
It seems that the .sd file format isn't documented anywhere, but, for the pictures, the Sample.sd file I've got seems to use JFIF (a subset of JPEG). The files you have may use a different format for the pictures, but you may be able to find a known header in the file.