| SDU | standard deviation unit; step-down unit |
|---|---|
| STEP | Sequential Test of Educational Programs |
| AI | accidental injury; accidentally incurred; adiposity index; aggregation index; allergy and immunology... |
| DI | date of injury; defective interfering [particle]; dentinogenesis imperfecta; deoxyribonucleic acid i... |
| IMPA | incisal mandibular plane angle |