Quality of periodontal healing. IV: Enzyme histochemical evidence for an osteoblast origin of reparative cementum.

The aim of the present study was to map the distribution of healing gingival and periodontal connective tissue well as osteoblastic activity in marginal periodontal wound healing using activity of alkaline phosphatases as markers. Activity of non-specific alkaline phosphatase (NSAP) was abundant in periodontal but not in gingival connective tissue. Activity of vanadate-resistant alkaline phosphatase (VRAP) had a preferential localisation to periosteal and endosteal bone surfaces but was not detectable in cementoblasts along root surfaces. However, following spontaneous marginal healing of exposed dentine surfaces, activity of VRAP was also found on healing dentine surfaces. It was concluded that osteoblasts rather than cementoblasts form reparative cementum on exposed dentine surfaces during marginal periodontal healing.