purified protein derivative 
Postpartum depression 
protein purified derivative 
packs per day 
Paired-pulse depression 
paraphenylenediamine 
peak particle diameter 
Perianal Paget's disease 
periodontal pocket depth 
periodontal probing depth 
permanent partial disability 
persistent pigment darkening 
personal and professional development 
pervasive devel disorder 
pervasive developmental disorder 
pocket probing depth 
Pocket probing depths 
polymorphous dystrophy 
posterior polymorphous dystrophy 
postpartum day 
Post-psychotic depression 
p-Phenylenediamine 
Preaxial polydactyly 
prep, position, drape 
preprodynorphin 
primary peritoneal drainage 
primary progressive dementia 
probing pocket depth 
probing pocket depths 
Progressive pseudorheumatoid dysplasia