Hypodontia of all primary canines.

BACKGROUND: Several hypotheses have been proposed to explain hypodontia of the various tooth types with evolutionary and anatomic models. Hypodontia of all primary canines in a healthy individual is exceptionally rare and has not been previously reported in the dental literature. CASE REPORT: This clinical report describes a 4-year-old southern Chinese female with the congenital absence of the primary canines in all quadrants. Furthermore, all of the permanent tooth germs excluding the third molars were evident on a panoramic radiograph and were developing consistent with the subject's chronological age. CONCLUSION: This case serves as an excellent example to refute the conventional wisdom that "all primary canines can never go missing" and that all of the currently proposed hypotheses to explain hypodontia have limitations.