Analysis of human alveolar osteoblast behavior on a nano-hydroxyapatite substrate: an in vitro study

Background: Nano-hydroxyapatite (nHA) is a potential ideal biomaterial for bone regeneration. However, studies have yet to characterize the behavior of human osteoblasts derived from alveolar bone on nHA. Thus, the aim of the present study was to evaluate the influence of nHA on the adhesion, proliferation and differentiation of these alveolar bone-derived cells.Methods: Primary human alveolar osteoblasts were collected from the alveolar ridge of a male periodontal patient during osseous resective surgery and grown on culture plates coated with either polylysine or polylysine with nano-hydroxyapatite (POL/nHA) composite. The cells were grown and observed for 14 days, and then assessed for potential modifications to osteoblasts homeostasis as evaluated by quantitative reverse transcriptase-polymerase chain reaction (real time RT-PCR), scanning electron microscopy and atomic force microscopy.Results: Real time PCR revealed a significant increase in the expression of the selected markers of osteoblast differentiation (bone morphogenetic protein (BMP)-2,-5,-7, ALP, COLL-1A2, OC, ON) in cells grown on the POL/nHA substrate. In addition, as compared with the POL surface, cells grown on the POL/nHA substrate demonstrated better osteoconductive properties, as demonstrated by the increase in adhesion and spreading, likely as a result of the increased surface roughness of the composite.Conclusions: The increased expression of BMPs and osteoinductive biomarkers suggest that nano-hydroxyapatite may stimulate the proliferation and differentiation of local alveolar osteoblasts and thus encourage bone regeneration at sites of alveolar bone regeneration

Which reconstructive procedures are effective for treating the periodontal intraosseous defect?

The aim of this article was to determine the effect of GTR, grafting procedures or the application of enamel matrix proteins in addition to OFD in the treatment of deep intraosseous defects. Overall, data resulting from systematic reviews indicate that all reconstructive treatment modalities produce comparable and more favorable clinical improvements in hard and soft tissue parameters of healing response (i.e. clinical attachment gain, pocket reduction and bone fill) compared to conventional OFD procedures. Although the biomaterial-supplemented reconstructive procedures are associated with a generally positive treatment effects with respect to OFD, a significant heterogeneity was found among studies in the different reconstructive procedures. This limits the possibility of drawing general conclusions about the clinical relevance (in particular, the magnitude of the adjunctive effect) of the additional use of GTR, grafting procedures or enamel matrix proteins for the treatment of intraosseous defects. Some of the possible causes of heterogeneity have been explored; however, the limited number of studies currently available did not permit definite conclusions about which factors account for the variability in treatment outcome. More research is therefore needed to identify patient, site, choice of material and technique factors associated with the successful outcome of treatment of intraosseous defects. This review indicates that different reconstructive procedures support comparable clinical outcomes. It should, however, be considered that similar improvements in clinical parameters do not necessarily imply similar wound healing processes on a histologic level. Whereas the use of some reconstructive procedures, such as GTR and enamel matrix proteins, has been demonstrated to result in a true and complete periodontal regeneration, for some of the graft biomaterials the effect on the formation of a new attachment apparatus, including bone, cementum and periodontal ligament, rather than periodontal repair, is still a matter of debate. Due to limited information on long-term outcomes, it is unclear whether the stability of periodontal support and tooth survival are affected by the additional application of reconstructive devices ⁄ biomaterials. While the improvements in probing recordings may be reasonably considered surrogate measurements related to a better long-term tooth prognosis, we recommend that more clinical studies should examine whether and to what extent more compromised teeth could be saved using a reconstructive procedure. There are at present insufficient data to permit analytic comparisons among different reconstructive procedures with OFD with respect to patient-centered outcomes. When considering the adjunctive effect of reconstructive procedures, evaluation of adverse effects related to the additional use of biomaterials ⁄ biological agents, postoperative complications, ease of maintenance, change in aesthetic appearance, estimation of patient well-being, and cost ⁄ benefit ratio (including estimation of additional treatment time and costs for implant ⁄ placement of biomaterials ⁄ biological agents) should be carried out. Studies including patient-centered outcomes will be critical, as well as long-term follow-up cohorts to examine the effect of a reconstructive biomaterial ⁄ device on true therapeutic endpoints