Pulsed laser sintering of photo-active calcium phosphates for dental enamel restoration

We investigated the laser sintering behaviour of rare-earth oxide doped calcium phosphate suspensions, which was applied on the surface extracted, disinfected, γ-ray irradiated teeth, surfaces of which were prepared apriori using dilute phosphoric acid. The natural dental enamel is a hydroxyl apatite, We refer to rare-earth doped calcium phosphates as the photo-active enamel mineral, which was then irradiated with both pulsed and CW lasers. For effective photo-activation of synthetic mineral leading to sintering with the natural enamel using pulsed laser, the calcium phosphate phase was doped with 1-2 wt% of Yb₂O₃ or Er₂O₃ oxide, which was dissolved into the suspension together with 2 wt% of aluminium phosphate (AlPO₄) 2 wt% calcium fluoride (CaF₂) and the remaining calcium phosphate constituents, which makes the majority of mineral. The synthesized mineral, unlike natural and synthetic needle like HAp, has platelet structure for providing larger surface occlusion, rapid heat transfer, and large surface area for sintering.