RESUMEN
BACKGROUND: We reviewed the biological and mechanical properties of porous hydroxyapatite (HA) compared to other synthetic materials. Computer-aided design/computer-aided manufacturing (CAD/CAM) was also evaluated to estimate its efficacy with clinical and radiological assessments. METHOD: A systematic search of the electronic literature database of the National Library of Medicine (PubMed-MEDLINE) was performed for articles published in English between January 1985 and September 2013. The inclusion criteria were (1) histological evaluation of the 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) comparison of the biological and mechanical properties between several biomaterials, and (4) clinical and radiological evaluation of the precision of CAD/CAM techniques. RESULTS: HA had excellent osteoconductivity and biocompatibility in vitro and in vivo compared to other biomaterials. HA grafts are suitable for milling and finishing, depending on the design. In computed tomography, porous HA is a more resorbable and more osteoconductive material than dense HA; however, its strength decreases exponentially with an increase in porosity. CONCLUSIONS: Mechanical tests showed that HA scaffolds with pore diameters ranging from 400 to 1200 µm had compressive moduli and strength within the range of the human craniofacial trabecular bone. In conclusion, using CAD/CAM techniques for preparing HA scaffolds may increase graft stability and reduce surgical operating time.
RESUMEN
The purpose of the present study was to assess the cumulative survival rate (CSR) of 192 implants placed in association with guided bone regeneration (GBR) procedures to evaluate the long-term predictability of this technique. Moreover, the Kaplan Meier survival analysis was applied to the data in order to evaluate predictors of implant failures, including the source of the graft, the type of membrane, and the timing of implant placement. The CSR of the sample was 95.6% over a mean follow-up period of 78 months (range, 1-175 months). Considering the source of graft, a 95.0%, 93.3%, and 97.7% CSR was obtained for demineralized bovine bone mineral (DBBM), autologous, and 1:1 ratio mixture of autologous and DBBM grafts,, respectively. The CSR referred to bioabsorbable membranes was 96.5%, whereas 94.6% was the CSR reported for nonresorbable membranes. The CSR of simultaneous surgeries was 96.8%, whereas staged surgeries showed a CSR of 94.5%. According to the data, implants placed in conjunction with GBR procedures presented a satisfying survival rate even in the long term. All the procedures performed with different bone grafts and type of membranes guaranteed optimal results both in one- and two-stage approaches. No statistically significant differences could be detected among the groups; indeed, the use of DBBM associated with resorbable membranes may be suggested to reduce patients' morbidity and treatment time. Therefore, the dental implants placed in association with bone regenerative procedures presented safe and predictable long-term clinical results.
