The rachitic tooth: A histological examination

Diagnosing previous episodes of vitamin D deficiency is particularly challenging due to the subtle changes retained in the skeleton. This study investigates whether abnormal mineralisation in tooth dentin can be observed in archaeological individuals with past vitamin D deficiency. Methods taken from the clinical literature were used, where defects in tooth dentin of those with deficiency have been identified. SEM and histological analysis of tooth dentin were utilized to diagnose vitamin D deficiency in adult and juvenile skeletal remains in individuals who recovered from a period of deficiency. Archaeological skeletons were from St. Matthew and St. Marie, Quebec (1771–1860), and St. Jacques, France (1225–1798). The objective was to determine if interglobular dentin could be observed in individuals with skeletal evidence of vitamin D deficiency. A differential diagnosis revealed that the only conditions that cause mineralisation defects are those that disrupt vitamin D, calcium, and phosphorous pathways, with nutritional rickets being the most common cause. Results found that all of the archaeological individuals (6/6) who showed skeletal evidence of past deficiency displayed the formation of interglobular dentin (spaces) due to unfused calcospherites, whereas interglobular dentin was absent in modern healthy controls (n = 3). We propose that a temporary inhibition of dentin growth leads to modification of calcospherite shape and size, resulting in characteristic interglobular spaces in individuals with deficiency. Although further research is needed, we conclude that systemic mineralisation problems of individuals with deficiency may cause dentin mineralisation to stop or falter, preventing further dentin growth and fusion. Dentin has the potential to enable past episodes of vitamin D deficiency to be recognized in cases where skeletal indicators are not clear.