CAD/CAM designed hydroxyapatite scaffold in jawbone defects: a systematic review

Objective: The aim of the review is firstly to verify the optimal mechanical and biological properties of hydroxyapatite (HA) in vitro and in vivo, comparing to other synthetic materials. Secondly the CAD/CAM technique using porous HA scaffold was evaluated to estimate its real efficacy with clinical and radiological assessments. Materials and Methods: A systematic literature search on the electronic database of National Library of Medicine (PubMed- MEDLINE) was conducted using search terms to identify relevant articles regarding the aim of the review. Inclusion criteria selected for the current systematic review are: 1) histological evaluation of the effective biocompatibility and osteoconductivity of porous HA in vivo and in vitro 2) evaluation of the mechanical properties of HA in relation to its porosity 3) compared evaluation of biological and mechanical properties between several biomaterials in order to assess whereas HA is preferable in relationship to different clinical situation 4) clinical and radiological evaluation of the precision of the CAD/CAM technique. Results: Among the synthetic materials, hydroxyapatite has proved excellent osteoconductivity and biocompatibility in vitro and in vivo comparing to other biomaterials. Porous hydroxyapatite (HA) is a more readily resorbable and more osteoconductive material than dense HA, however the strength decreases exponentially with the increase of the porosity. Mechanical tests showed that fabricated HA scaffolds with pore diameters ranging from 400 to 1200 microns had compressive modulus and strength within the range of human craniofacial trabecular bone; this implies that they can be easily used for bone regenerative rehabilitations. Conclusion: Several studies in vivo have evaluated optimal clinical and radiological results using HA scaffold as grafts before implants position even after several months on both human mandibula and maxilla. In conclusion, using CAD/CAM technique for HA scaffold could increase grafts stability and reduce surgical operative time.