Acid bone lysates (ABLs) represent the growth factors and other molecules released during autologous graft resorption. However, the impact of these bone‐derived growth factors on the healing of bone defects has not yet been investigated. The aim of the present study was, therefore, to examine the impact of ABLs adsorbed to collagen membranes on bone regeneration. To this end, in 16 female Sprague Dawley rats, a standardized 5‐mm‐diameter critical size defect on the calvarial bone was created. The defects were covered with collagen membranes that had been soaked either in serum‐free media or ABLs followed by lyophilization. After a healing period of 4 weeks, micro‐computed tomography (μCT) and histological analyses by means of undecalcified thin ground sections were performed. μCT analysis of the inner 4 mm of the calvaria defect showed a greater bone defect coverage in the control group when compared to ABL group, 29.8% (confidence interval [CI]: 17.7–50.3) versus 5.6% (CI: 1.0–29.8, p = .03), respectively. Moreover, we found significantly more absolute bone volume (BV) in the control group when compared to ABL group, 0.59 mm3 (CI: 0.27–1.25) versus 0.07 mm3 (CI: 0.06–0.59, p = .04), respectively. Histomorphometry confirmed these findings with a relative BV in the central compartment of 14.1% (CI: 8.4–20.6) versus 5.6% (CI: 3.4–7.9, p = .004), respectively. These findings indicate that bone‐derived growth factors contained in ABLs are able to attenuate bone regeneration within collagen membranes.

Objective:This study aimed to evaluate the effects of continual intermittent administration of parathyroid hormone (PTH) on implant stability in the presence of osteoporosis, using rabbit models.Material and Methods:Fifteen female New Zealand white rabbits underwent ovariectomy and were administered glucocorticoids to induce osteoporosis, following which they were divided into three groups. The first group received intermittent subcutaneous PTH for 4 weeks until implant placement (PTH1), while the second and third groups received PTH (PTH2) and saline (control), respectively, for 4 weeks before and after implant placement. After intermittent administration of PTH or saline, titanium implants were inserted into the left femoral epiphyses of all animals, and the implant stability quotient (ISQ) was measured immediately after placement to assess the primary stability and at 2 and 4 weeks after implant placement to assess osseointegration. At 4 weeks after implant placement, histological and histomorphometric evaluations were conducted and the bone area around the implant socket was measured as a ratio of the total bone area to the total tissue area.Results:Regarding primary stability, the ISQ values for the PTH1 and PTH2 groups were significantly higher than those for the control group (p<0.05). Concerning osseointegration, the ISQ values at 2 and 4 weeks were significantly higher for the PTH2 group than for the PTH1 and control (p<0.05) groups. Histological assessments showed a thicker and more trabecular bone around the implant sockets in the PTH2 specimens than in the PTH1 and control specimens. The bone area around the implant socket was significantly greater in the PTH2 group than in the PTH1 and control groups (p<0.05).Conclusions:Our results suggest that continual intermittent PTH administration before and after dental implant placement is effective for the achievement of favorable stability and osseointegration in the presence of osteoporosis.

Objectives: MicroRNAs (miRNAs) are small noncoding RNAs demonstrated as critical post-transcriptional modulators in dental tissues and bone regeneration, particularly miR-21-5p. However, the role of miR-21-5p in the healing of alveolar sockets following tooth extraction remains unknown. In this study we evaluated the influence of miR-21-5p in the healing of alveolar socket after tooth extraction. Methods: Eight miR-21-5p knockout mice and eight littermate controls underwent tooth extraction of the upper right incisor. After a healing period of 14 days microCT and histological analyses were performed. Results: MicroCT analysis showed that the percentage of bone in the extraction socket was significantly higher in the control group than in the miR-21 knockout mice; either in the coronal (39.0%, CI 31.8 to 48.0 versus 23.0%, CI 17.8 to 35.2, P = 0.03) or in the middle part of the alveolar socket (56.0%, CI 50.9 to 62.5 versus 43.5% CI 28.6 to 54.6, P = 0.03). These differences were not noted in the apical part of the extraction socket. Histological analysis supported the microCT findings. Newly bone volume per tissue volume (BV/TV) was significantly higher in the control group when compared to miR-21 knockout mice, 27.4% (CI 20.6 to 32.9) This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

The purpose of this study was to evaluate the characteristic structures and osteoconduction ability of porous titanium structures using a resin-impregnated titanium substitution fabrication technique.