BACKGROUND: As a two-stage surgical procedure, Masquelet\'s technique has been used to care for critical-size bone defects (CSD). We aimed to determine the effects of modified and altered bone cement with biological or chemical enriching agents on the progression of Masquelet\'s induced membrane (IM) applied to a rat femur CSD model, and to compare the histopathological, biochemical, and immunohistochemical findings of these cements to enhance IM capacity.
METHODS: Thirty-five male rats were included in five groups: plain polymethyl methacrylate (PMMA), estrogen-impregnated PMMA (E+PMMA), bone chip added PMMA (BC+PMMA), hydroxyapatite-coated PMMA (HA) and calcium phosphate cement (CPC). The levels of bone alkaline phosphatase (BALP), osteocalcin (OC), and tumor necrosis factor-alpha (TNF-α) were analyzed in intracardiac blood samples collected at the end of 4 weeks of the right femur CSD intervention. All IMs collected were fixed and prepared for histopathological scoring. The tissue levels of rat-specific Transforming Growth Factor-Beta (TGF-β), Runt-related Transcription Factor 2 (Runx2), and Vascular Endothelial Growth Factor (VEGF) were analyzed immunohistochemically.
RESULTS: Serum levels of BALP and OC were significantly higher in E+PMMA and BC+PMMA groups than those of other groups (P = 0.0061 and 0.0019, respectively). In contrast, TNF-α levels of all groups with alternative bone cement significantly decreased compared to bare PMMA (P = 0.0116). Histopathological scores of E+PMMA, BC+PMMA, and CPC groups were 6.86 ± 1.57, 4.71 ± 0.76, and 6.57 ± 1.51, respectively, which were considerably higher than those of PMMA and HA groups (3.14 ± 0.70 and 1.86 ± 0.69, respectively) (P < 0.0001). Significant increases in TGF-β and VEGF expressions were observed in E+PMMA and CPC groups (P = 0.0001 and <0.0001, respectively) whereas Runx2 expression significantly increased only in the HA group compared to other groups (P < 0.0001).
CONCLUSIONS: The modified PMMA with E and BC, and CPC as an alternative spacer resulted in a well-differentiated IM and increased IM progression by elevating BALP and OC levels in serum and by mediating expressions of TGF-β and VEGF at the tissue level. Estrogen-supplemented cement spacer has yielded promising findings between modified and alternative bone cement.

In order to reduce bone tissue damage, the effect of crescent texture parameters on the axial force during bone drilling was investigated. The biomimetism micro-texture shape was selected from a bionic point of view. A laser marking machine was used to process biomimetism crescent texture on the rake face of the drill bit, and then a theoretical model of axial force is established to determine the relationship between axial force and texture parameters according to actual chip-tool contact area. A test platform for drilling bone was built to prove the theoretical model. The novelty of the study involved predicting the change of the axial force according to the true chip-tool contact area. The experimental results showed that a biomimetism crescent texture on the rake face of a drilling tool significant reduced the axial force during bone drilling compared with that of a non-textured tool. Within the range of the experiment data, during the stage of drill entry and stabilization, the measured axial force of a micro-textured tool was more stable and the fluctuation in stress was lower, compared to the response from a conventional drilling tool.

Bone drill chips that are collected during implant site preparation can be reused as autologous bone-grafting material for alveolar ridge augmentation. This study characterized five market-leading implant drill sets regarding their geometric properties and ability to produce vital bone chips. The drill geometry of each tool of five commercial implant drill sets was characterized while using optical profile projector devices and SEM. Bone chips were collected during the in vitro preparation of porcine jaw bone with the various drill sets. Produced bone chip masses were measured. The bone chips were cultured in vitro and the number of outgrown cells was determined and measurand for vitality. Furthermore, the thrust force and cutting torque were recorded to examine the mechanical loads of the manual drilling process. The tool geometry and set configuration of one out of five implant drill sets appears to be superior regarding chip mass, vitality, and thrust force. It could be proven that there is a correlation between vitality and thrust force. The thrust force is influenced by the cutting behavior of the tool, which in turn depends on the geometry of the tool. The tool geometry has an influence on the vitality of the augmentation material due to this relationship.

The aim of the study was to evaluate whether the use of a xenograft is not inferior to the use of xenograft and autogenous bone chips in treating dehiscences at implant placement.
After implant placement, leaving a dehiscence, control sites were treated using a composite graft (autogenous bone chips and xenograft) and at the test sites 100% xenograft was used. Both sites were covered with a resorbable collagen membrane. Dehiscences were measured clinically at implant placement and at re-entry. CBCT was taken immediately after implant placement and after 4 months.
In total, 28 GBR procedures were performed in 14 patients. On average, the change in vertical defect height was 2.07 mm (46.7%-test group) and 2.28 mm (50.9%-control group) (p > .05). The horizontal defect width at the implant shoulder change on average 1.85 mm (40.5%-test group) and 1.75 mm (40.9%-control group) (p > .05). On average, a loss in augmentation thickness of 0.45 mm (68.9%-test group) and 0.64 mm (55.5% control group) between implant placement and augmentation and abutment surgery was obtained at the implant shoulder.
Both treatment modalities seem to work to a certain extent. At implant shoulder level, the augmentation thickness seems to be disappeared after the healing phase. (NCT03946020).

Guidelines suggest culturing clinically uninfected bone at the margin after surgical resection for osteomyelitis, but little published evidence supports this procedure. To investigate whether culturing marginal bone after completing resection of infected bone affected antibiotic use or further surgical intervention, we collected data on sequential patients undergoing amputation for a foot infection at our tertiary care hospital between January 2014 and May 2015. We recorded patient age, sex, presence of diabetes mellitus, level of amputation, whether marginal bone was sent for culture, microbiology of any marginal bone specimens, type and duration of antibiotic therapy, and any further surgical resection. Among 132 patients, the mean age was 71.9 years, 103 (78.0%) were male, and 79 (59.8%) had diabetes. Treating surgeons sent marginal bone in 58 (43.9%) of these patients, 50 (86.2%) of which were culture positive. Patients with a positive bone culture were significantly more likely to undergo further surgical intervention (20.0% vs 6.1%, p = .047). For patients with diabetes, compared with those without, surgeons did not send marginal bone for culture more often (46% vs 42%, p = .72), nor did they undertake further surgical interventions more frequently (13.4% vs 10.1%, p = .89). Our results suggest that the clinicians used the marginal bone culture findings to make clinical decisions but do not clarify if there is a benefit to performing this procedure. Although patients whose proximal bone specimens were culture positive were more likely to undergo a surgical intervention, the reasons for, and benefit of, this additional surgery were unclear.

The preservation of bone viability at an osteotomy site is a critical variable for subsequent implant osseointegration. Recent biomechanical studies evaluating the consequences of site preparation led us to rethink the design of bone-cutting drills, especially those intended for implant site preparation. We present here a novel drill design that is designed to efficiently cut bone at a very low rotational velocity, obviating the need for irrigation as a coolant. The low-speed cutting produces little heat and, consequently, osteocyte viability is maintained. The lack of irrigation, coupled with the unique design of the cutting flutes, channels into the osteotomy autologous bone chips and osseous coagulum that have inherent osteogenic potential. Collectively, these features result in robust, new bone formation at rates significantly faster than those observed with conventional drilling protocols. These preclinical data have practical implications for the clinical preparation of osteotomies and alveolar bone reconstructive surgeries.

BACKGROUND: High dose radiation therapy is commonly used in maxillofacial surgeries to treat a number of head and neck tumors. Despite its widespread use, little information is available regarding the effects of irradiation on bone cell viability and release of growth factors following dose-dependent irradiation.
METHODS: Bone samples were collected from porcine mandibular cortical bone and irradiated at doses of 0, 7.5, 15, 30, 60 and 120 Grays. Thereafter, cell viability was quantified, and the release of growth factors including TGFβ1, BMP2, VEGF, IL1β and RANKL were investigated over time.
RESULTS: It was observed that at only 7.5Gy of irradiation, over 85 % of cells were non-vital and by 60 Gy, all cells underwent apoptosis. Furthermore, over a 7-fold decrease in VEGF and a 2-fold decrease in TGFβ1 were observed following irradiation at all tested doses. Little change was observed for BMP2 and IL1β whereas RANKL was significantly increased for all irradiated samples.
CONCLUSIONS: These results demonstrate the pronounced effects of irradiation on bone-cell vitality and subsequent release of growth factors. Interestingly, the largest observed change in gene expression was the 7-fold decrease in VEGF protein following irradiation. Future research aimed at improving our understanding of bone following irradiation is necessary to further improve future clinical treatments.

Bone scrapers are commonly used to harvest autologous bone in oral and implant surgery. The angle of the cutting blade is a variable that distinguishes bone scrapers. In the present study, the impact of the angle of the cutting blade on the in vitro characteristics of harvested bone was determined. Bone scrapers with blade angles of 15°, 25°, 35°, 45°, and 55° were used to harvest porcine cortical mandibular bone. The number and characteristics of the cells that grew out from the bone chips were examined. The data showed that, independent of the angle of the cutting blade, viable cells were barely detectable in fresh bone grafts. However, cells with a fibroblastic morphology appeared within 1 week in the culture dishes. After 21 days, the number of cells did not differ significantly between the five preparations. Moreover, cells responded to incubation with bone morphogenetic protein 7 (BMP-7) with an increased alkaline phosphatase activity, irrespective of the preparation. The data suggest that bone scrapers with different cutting angles produce bone chips with comparable in vitro characteristics.