Prolonged retention of primary teeth rarely poses clinical
problems in modern people if these teeth are extracted and
the eruptive paths of permanent teeth are normalized. In the
field of physical anthropology, one sometimes encounters
ancient human skeletal remains with over-retained primary
teeth, however, the scientific report is very few [1]. There
have been various reports on temporomandibular joint (TMJ)
arthritis and temporomandibular disorder (TMD) [2,3].
However, my literature search on the PubMed database did
not reveal any report on the relationship between TMD and
over-retained primary teeth. A report in a Japanese journal
has shown that when primary teeth were retained beyond the
normal period, their extraction resulted in gradual
improvement of TMD and in normal occlusion