PTH and diabetes mellitus: Some studies showed that PTH did not increase the insulin-immunoreactivity of β-cells of the pancreatic islets in diabetic rats.24 The inflammation caused by diabetes would disrupt vascular endothelial cell function.25 The expression of inflammatory cytokines such as TNF-α, IL-1 and IFN-γ in bone increased,26 , 27 which contributed to the delayed healing of extraction sockets.