Affect Bone Healing Research Articles

Femoral shaft fracture with a third fragment treated with an intramedullary nail: Is the displacement of the third fragment predictive of nonunion?

Femoral shaft fractures with third fragments are difficult to reduce anatomically, affecting bone healing chances. The goal of this study is to determine the impact of the third fragment's radiological characteristics assessed on post-operative radiographs, as well as other factors, on the healing of type 32B femur shaft fractures treated with intramedullary nail. We conducted a retrospective study of 93 patients treated for femoral shaft fractures type 32 B. On post-operative X-rays, two radiologic parameters were evaluated: the third fragment size and the mean third fragment displacement. Patients had radiologic follow-up at 2, 4, 6, 9, and 12-months and were separated into 3 groups based on their fracture healing time: within 6months (group 1), between 6 and 12months (group 2), or nonunion after 12months (group 3). Among the 93 patients, 72 (77.4%) showed fracture healing at 6months, 13 (14%) at 12months, and 8 (8.6%) demonstrated nonunion at 12months. The mean third fragment displacement was notably different between groups (p < 0.001) and was considerably greater in group 3 than in groups 1 and 2. The influence of third fragment displacement on outcomes under 6months was determined by ROC analysis, using a cut-off value of 14mm. Displacement under 14mm predicted healing within 6months with a sensitivity of 90.3% and a specificity of 61.9%. The statistical analysis demonstrated that the odds of experiencing non-union or delayed healing were approximately 15 times higher for patients with a third fragment displacement of 14mm or greater. The third fragment displacement is the most important factor influencing healing within twelve months in femur shaft fractures type 32B managed with an intramedullary nail. Inversely, the third fragment size had no effect on the healing of the fractures in our series.

Novel Technique for Alveolar Ridge Expansion: A Comparative Clinical Study

Background: Piezosurgery improved the split approach by making it safer, easier, and less prone to complications when treating extremely atrophic crests. Densah drills, with their unique design, expand the ridge by densifying bone in a reverse, non-cutting mode. Objective: To assess the effectiveness of sagittal piezosurgery, which involves cutting bone to the full implant depth and then expanding it using osseodensification drills. We use this technique to expand narrow alveolar bones and simultaneously place dental implants in the maxillary and mandibular arches. Methods: Fourteen patients received 31 dental implants. The maxillary arch received 19, and the mandible received 12 dental implants. This study will include patients who have narrow alveolar bone ridges (2.5–4 mm). After marking the implant sites with a pilot drill, we used a piezoelectric surgery tip to cut the alveolar crest to the depth of the planned dental implant. We then sequentially used Versah Drills, accompanied by extensive irrigation using cooled, sterile normal saline, and finally inserted the implant into the subcrestal level. Results: This study revealed a significant difference in alveolar ridge width immediately after the procedure, and the significant change in the mandible was slightly higher than that in the maxillary arch. However, all implants in both jaws achieved successful osseointegration. Conclusions: The alveolar ridge width changed a lot more in the mandible than in the maxillary arch after the procedure. These two strategies work well together to properly and simply expand severely atrophied alveolar ridges without affecting bone healing or the osseointegration process.

Effectiveness and Biocompatibility Evaluation of a Novel Absorbable Bone Wax Used in Bone Tissue.

This study aims to determine the hemostatic effectivity and biocompatibility of a novel absorbable bone wax in comparison with a commercially available product. Eighteen small fat-tail sheep were used to simulate clinical surface bleeding of sternal injury. Hemostasis effectiveness, the degree of bone healing, micro-computed tomography, and histopathology were evaluated over a period after the application of the material to the surgically created wound. The absorbable bone wax used in the study stopped bleeding immediately and did not affect bone healing. The histopathological results also showed that there were no complications associated with the new material. The results showed that the new absorbable bone wax used in this study was effective and biocompatible.

Evaluation of the Effects of Locally Applied Resveratrol and Cigarette Smoking on Bone Healing

Background: Bone healing is a complex process controlled by various mechanisms. It is known that cigarette smoking (CS) negatively affects bone healing by disrupting many of these mechanisms. In an effort to find ways to eliminate these negative effects caused by CS, studies have been conducted on various vitamins, antioxidants, and medications. Since high doses and repeated injections are required to increase the therapeutic effect of conventional drug applications, controlled drug delivery systems have been developed to avoid such problems. This study aimed to investigate the effects of resveratrol (RES), which has been made into a controlled drug delivery system, on bone healing in rats that were experimentally exposed to cigarette smoke to create a chronic smoking model. Methods: After establishing a chronic CS model by exposing the subjects to cigarette smoke of six cigarettes/day for four weeks, monocortical critical size defects of 3 mm (SD ± 0.02 mm) in diameter were created in the femur using a trephine bur. During the operation, the defects in RES groups were filled locally with a gel-formed solution of RES (50 µM) and Pluronic F-127 (14 µL). CS exposure was continued during the bone healing period after surgery. All groups were sacrificed one month after the operation, and femur samples were taken. Results: The obtained samples were examined by histomorphometric and immunohistochemical techniques; osteoblast count, new bone area, macroscopic filling score, vascularization, and proliferation were evaluated. Conclusion: The results of this study indicate that CS negatively affects bone healing and that local application of RES reduces this effect.

Current application and future perspectives of antimicrobial degradable bone substitutes for chronic osteomyelitis.

Chronic osteomyelitis remains a persistent challenge for the surgeons due to its refractory nature. Generally, treatment involves extensive debridement of necrotic bone, filling of dead space, adequate antimicrobial therapy, bone reconstruction, and rehabilitation. However, the optimal choice of bone substitute to manage the bone defect remains debatable. This paper reviewed the clinical evidence for antimicrobial biodegradable bone substitutes in the treatment of osteomyelitis in recent years. Indeed, this combination was proved to eradicate infection and facilitate bone reconstruction, which might reduce the cost and hospital stay. Handling was associated with increased risk of unwanted side effect to affect bone healing. The study provides some valuable insights into the clinical evaluation of treatment outcomes in the aspects of infection eradication, bone reconstruction, and complications caused by materials. However, achieving complete infection eradication and subsequently perfect bone reconstruction remains challenging in compromised conditions, hence advanced innovative bone substitutes are imperative. In this review, we mainly focus on the desired functional effects of advanced bone substitutes on infection eradication and bone reconstruction from the future perspective. Handling property was optimized to simplify surgery process. It is expected that this review will provide an important opportunity to enhance the understanding of the design and application of innovative biomaterials to synergistically eradicate infection and restore integrity and function of bone.

Recent developments on cells involved in bone repair and their potential clinical applications

This review of the literature has summarized recent developments on cells implicated in the different phases of bone healing and their potential clinical applications including inflammatory phase (neutrophils, macrophages, mast cells), fibrovascular phase (endothelial cells and mesenchymal stem cells - MSCs), bone formation (osteoblasts, chondrocytes), and callus remodeling (osteoclasts). Some studies have confirmed the two well-known facts that alcohol intake and dexamethasone negatively affect bone healing. Other studies have shown that Aucubin, Bortezomib, and human umbilical cord MSCs (HUCMSCs)Wnt10b promote bone healing of bone fractures. However, more research is needed to confirm their actual utility in the clinical practice of bone fracture treatment.

Comparative Clinical Effects and Risk Factors Associated With Vitamin D in Foot and Ankle Fracture and Arthrodesis Healing

Vitamin D deficiency in relation to bone metabolism and healing has been controversial and not well studied. However, hypovitaminosis has been widely identified within the orthopedic patient population. The current best evidence suggests a lack of data on this important topic. The ability to assess patients for optimum bone healing and metabolism is still in question due to lack of a suitable reliable biomarker and multiple other unknown variables affecting bone metabolism. To compound this effect, popular dermatological precautions in the last 20 to 30 years of avoiding sunlight also have the effect of further reducing serum vitamin D production in the skin. As a proof of concept, we performed a preliminary comparative observational retrospective review of orthopedic patients undergoing fracture and arthrodesis osseous healing to determine how serum vitamin D levels are associated with bone healing along with their confounding comorbidities. Based on our review, the current accepted vitamin D levels (≥20 ng/mL) are low and insufficient for fractures and for arthrodesis osseous healing due to observed high rates (>35%) of delayed unions, and an increased (>90%) in the number of multiple confounding comorbidities affecting bone healing process that are often not mentioned or captured in this type of study in previous literature. Obesity and diabetes are significant contributory risks factors, and the preliminary findings suggest that the current accepted adequate levels may not be enough for osseous healing. These low vitamin D levels appear to affect bone healing and prolong treatment, with worsening trends with diabetes and obesity comorbidities.

Is the High Healing Index a Complication of Progressive Long Bone Lengthening? Observations from a Cohort of 178 Children Treated with Circular External Fixation for Lower Limb Length Discrepancy.

The use of external fixators (EFs) for lower limb lengthening is common for treating lower limb length discrepancy (LLD) in children. The concern at present revolves around extended treatment times, with some suggesting a healing index (HI) > 45 days/cm as a major complication. The aim of this study is to assess the factors affecting bone healing and treatment duration in children who undergo limb lengthening for LLD using circular EFs. A total of 240 lengthening procedures on 178 children affected by congenital or acquired LLDs (mean age at surgery 13.8 ± 2.8 years) were retrospectively evaluated. Complications according to Lascombes' classification and treatment duration factors were analyzed. Mean HI was 57 ± 25 days/cm for the femur and 55 ± 24 days/cm for the tibia, with an HI > 45 days/cm in 64% of the procedures. A total of 189 procedures (79%) reported complications; 85 had an HI > 45 days/cm as the sole complication. While reducing the frame time is crucial, revising the classifications is necessary to avoid the overestimation of complications.

Evaluation of Preventive Role of Systemically Applied Erythropoietin after Tooth Extraction in a Bisphosphonate-Induced MRONJ Model.

Background and Objectives: In this experimental study, the prophylactic effect of systemically administered erythropoietin (EPO) in medication-related osteonecrosis of the jaw (MRONJ) was evaluated. Materials and Methods: The osteonecrosis model was established using 36 Sprague Dawley rats. EPO was systemically applied before and/or after tooth extraction. Groups were formed based on the application time. All samples were evaluated histologically, histomorphometrically, and immunohistochemically. A statistically significant difference in new bone formation was observed between the groups (p < 0.001). Results: When new bone-formation rates were compared, no significant differences were observed between the control group and the EPO, ZA+PostEPO, and ZA+Pre-PostEPO groups (p = 1, 0.402, and 1, respectively); however, this rate was significantly lower in the ZA+PreEPO group (p = 0.021). No significant differences in new bone formation were observed between the ZA+PostEPO and ZA+PreEPO groups (p = 1); however, this rate was significantly higher in the ZA+Pre-PostEPO group (p = 0.009). The ZA+Pre-PostEPO group demonstrated significantly higher intensity level in VEGF protein expression than the other groups (p < 0.001). Conclusions: Administering EPO two weeks pre-extraction and continuing EPO treatment for three weeks post-extraction in ZA-treated rats optimized the inflammatory reaction, increased angiogenesis by inducing VEGF, and positively affected bone healing. Further studies are needed to determine the exact durations and doses.

Effects of dynamization timing and degree on bone healing of different fracture types.

Dynamization, i.e., increasing interfragmentary movement (IFM) by reducing fixation stiffness from a rigid to a more flexible state, has been successfully used in clinical practice to promote fracture healing. However, it remains unclear how dynamization timing and degree affect bone healing of different fracture types. Finite element models of tibial fractures based on the OTA/AO classification (Simple: A1-Spiral, A2-Oblique, A3-Transverse; Wedge: B2-Spiral, B3-Fragmented; Complex: C2-Segment, C3-Irregular), in combination with fuzzy logic-based mechano-regulatory tissue differentiation algorithms, were used to simulate the healing process when dynamization of varied degrees (dynamization coefficient or DC = 0-0.9; 0.9 represents 90% reduction in the fixation stiffness relative to a rigid fixation) were applied at different time points after fracture. The fuzzy logic-based algorithms have been validated with a preclinical animal model. The results showed that the healing responses of type A fractures were more sensitive to the changes in dynamization degree and timing comparing with type B or C fractures. Additionally, the optimal dynamization regime for each fracture type was different. For type A fractures, a moderate dynamization degree (e.g., DC = 0.5) applied after week 1 promoted the recovery of biomechanical integrity. For type B and C fractures, the effective dynamization included a greater dynamization degree (DC=0.7) applied after week 2. Our results further demonstrated that the fracture morphology affected interfragmentary strain environments within the callus, leading to varied healing results for different fracture types. These results suggest that the effects of dynamization are highly dependent of the fracture types. Therefore, specific dynamization strategies should be chosen for different fracture types to achieve optimal healing outcomes. This article is protected by copyright. All rights reserved.

Lisinopril-Induced CD34 Bone Healing Marker

Background: Lisinopril is an angiotensin-converting enzyme (ACE) inhibitor that is commonly used to treat high blood pressure and heart failure. While it is generally well-tolerated, some studies have suggested that it may affect bone healing, suggesting that lisinopril treatment was associated with an increase in the CD34 bone healing marker in patients with tibial fractures. CD34 is a protein that is involved in the formation of new blood vessels and has been shown to play a role in bone healing. Methods: The study used 24 rabbits with artificially induced tibial bone fracture divided into 4 groups (6 rabbits each), the control group treated with distilled water and 3 groups treated with lisinopril. Each group were sacrificed for immunohistochemical study on 3 timepoints at day 7, 14, and 21. Results: Indicated that the lisinopril group had significantly higher levels of CD34 than the control group. Conclusion: While the results of this study suggest that lisinopril may have a positive effect on bone healing, more research is needed to confirm these findings and to determine the mechanisms by which lisinopril may affect bone healing. It is also important to note that lisinopril may have other potential side effects, and patients should discuss any concerns with their healthcare provider

Morphological Changes in the Tibial Tunnel After ACL Reconstruction With the Outside-In Technique and Adjustable Suspensory Fixation.

Anterior cruciate ligament reconstruction (ACLR) using the complete tibial tunnel technique and adjustable-loop cortical suspensory fixation is known to leave a "dead space" that holds the loop device in the tibial tunnel. The consequence of the dead space and its effect on graft healing are still uncertain. To investigate morphological changes in the tibial tunnel and their effect on graft healing, and to identify factors affecting bone healing in the tibial loop tunnel after ACLR with a quadrupled semitendinosus tendon autograft using adjustable suspensory fixation. Case series; Level of evidence, 4. Included were 48 patients (34 male, 14 female; mean age, 25.2 ± 5.6 years) who underwent ACLR with a quadrupled semitendinosus tendon autograft using adjustable suspensory fixation. To evaluate tibial tunnel morphology, computed tomography was performed at 1 day and 6 months postoperatively. At 1 year postoperatively, graft healing was assessed on magnetic resonance imaging using the graft signal-to-noise quotient (SNQ). Multivariate regression and correlation analyses were performed to determine any associations between volumetric changes in bone healing and operative variables. At 6 months after ACLR, a mean of 63.2% of the tibial loop tunnel was filled by bone. Multivariate regression analysis showed that remnant preservation was significantly associated with the loop tunnel filling rate (P < .001). At 1 year after ACLR, the tibial loop tunnel was almost completely closed (98.5%). There were no correlations between loop tunnel volume and graft integration or graft SNQ. A significant but weak correlation was found between graft tunnel volume and intratunnel graft SNQ (P = .10) as well as integration grade in the tibial tunnel (P = .30). Excellent bone filling in the tibial loop tunnel was seen at 1 year after ACLR. Remnant preservation was significantly associated with the loop tunnel filling rate. A weak correlation was found between graft tunnel volume and intratunnel graft SNQ as well as integration grade in the tibial tunnel.

Three-Dimensional Printed Polycaprolactone Mesh in Pediatric Cranial Vault Remodeling Surgery.

The surgical management of craniosynostosis has greatly evolved with improvements in both technology and understanding of the disease process. Some drawbacks remain regarding bone regeneration within the surgical bony gaps. Generally, bony gaps improve in the 12 to 24 months after surgery, but some gaps may remain for longer and cause deformity and/or require additional bony reconstruction. These considerations make tissue-engineered bone very attractive. Novel 3-dimensional printed bioresorbable mesh implants made of Polycaprolactone (PCL) can be used to fill the surgical bony defects. The authors seek to investigate how the use of a 3-dimensional printed biodegradable PCL mesh applied to bony defects in cranial vault surgery affects bone healing. Case series analysis of 8 pediatric patients who have undergone surgical intervention using PCL mesh implants for reconstruction of bony defects during craniosynostosis correction surgery. Radiological evaluation of 3 patients at random time points between 9 and 12 months postoperative revealed persistent bony gaps in areas where PCL mesh was laid. One patient who underwent a subsequent cranial vault surgery at 9 months was found to have less bone regeneration in the defect area where PCL mesh was used when compared with an adjacent area where a particulate bone graft was used. Based on our experience, the use of PCL mesh on its own did not augment bone regeneration. It is possible that a greater amount of time or increased vascularization of the scaffold is required, which supports the concept of regenerative matching axial vascularization or the further addition of osteogenic factors to increase the rate of bone formation.

Does the use of i-FACTOR bone graft affect bone healing in those undergoing periacetabular osteotomy (PAO) for hip dysplasia?

Introduction: Developmental Dysplasia of the hip (DDH) is a common cause of hip pain and a leading cause of early-onset hip osteoarthritis. Periacetabular osteotomy (PAO) aims to delay progression of osteoarthritis in those with DDH. As with any surgical procedure there are risks of complications, resulting in long-term pain and reduced function. The most common major surgical complication following PAO is bone non-union. Appropriate bone healing is a major focus of early rehabilitation as it allows full weightbearing capacity and physical activity progression.

Mid-Term Outcomes of Cemented Stem and Subtrochanteric Shortening Derotational Osteotomy in Total Hip Arthroplasty for Crowe IV Developmental Dysplasia.

Performing subtrochanteric osteotomy with cemented components in patients with Crowe IV developmental dysplasia of the hip (DDH) is technically challenging and not widely reported. This study aimed to evaluate the mid-term outcomes of cemented stem total hip arthroplasty (THA) with subtrochanteric femoral shortening and transverse derotational osteotomy in patients with Crowe IV DDH. Data collected from patients with Crowe IV DDH who underwent cemented stem THA with subtrochanteric femoral shortening and transverse derotational osteotomy between 2010 and 2018 were retrospectively evaluated. The cemented Lubinus SP II femoral component and the cementless CombiCup acetabular component were used together in all cases. These data, including Harris hip scores, limb length discrepancy (LLD), severity of limp, Trendelenburg test, bone union, length of the resected femur, limb lengthening, level of the osteotomy site, and length bridging the osteotomy site, as well as complications, were analyzed. A paired Student t-test was used to analyze continuous variables, categorical data were compared using Fisher's exact probability test, and correlation analysis was performed using Spearman's rank correlation coefficient. Among 14 included patients (10 females and four males), the mean age was 60.4 years (range, 47-73). The mean follow-up period was 49.1 months, and no patient was lost to follow-up. The mean Harris hip score improved from 40.7 to 87.7. The mean LLD decreased from 52 to 12.7 mm. The mean length of the excised femoral segment was 38.4 mm, and the mean length of limb lengthening was 27.1 mm. The mean distance between the osteotomy site and the lesser trochanter was 21.1 mm after surgery. The mean length of the femoral stem bridging the osteotomy site was 97.6 mm. Finally, the mean osteotomy union time was 10.6 months. No statistically significant correlation was found between the osteotomy union time and these factors. No neurological deficits were noted. Delayed union was observed in one patient, and postoperative dislocation was observed in two patients. Cement leakage into the osteotomy gap was observed in one patient, however, no revisions were required, and no signs of loosening or migration were observed. Cemented stem THA combined with subtrochanteric femoral shortening and transverse derotational osteotomy is safe and effective in treating patients with Crowe IV DDH. Rather than leading to nonunion, cement leakage may negatively affect bone healing.

Smoking Affects Bone Healing and Blood Perfusion

Nicotine is the primary component in cigarettes that is responsible for the negative effects that tobacco has on the body. Nicotine is also the primary component responsible for the addiction that can develop from smoking. Tobacco addiction is also primarily caused by nicotine, which is another component of tobacco. Aim: The effect that nicotine has on the rate at which bones can recover after being shattered is still a topic of ongoing debate. The study of bone repair and regeneration is made a great deal easier by the utilisation of a model that is known as distraction osteogenesis. The mandibular extension of a rabbit model is serving as the subject of the inquiry that is now being conducted. Duration &amp; Place of Study: October 2018 to March 2021 Rashid Latif medical college Lahore Method: Using the rabbit as a test subject, the purpose of this study is to evaluate the influence that nicotine has on blood perfusion, angiogenesis, and bone formation. There were a total of forty rabbits, and they were distributed among the control group, which received no nicotine, and the nicotine group, which received nicotine. The bunnies were distributed to the several groups in a haphazard manner. It was discovered that each rat had been exposed to nicotine or a placebo for a total of seven weeks during the course of the experiment. After a period of consolidation time ranging from two to four weeks post osteotomy, the animals were slaughtered and their mandibles were removed. After this, there was a lag time of three days, and then there was active distraction for eleven days. Utilizing the techniques of Laser Doppler monitoring and Collagen IV immunohistochemical labelling, respectively, allowed for the assessment of both vascularization and blood perfusion. Studies that were radiographic, histological, and immunohistochemical in nature were carried out in order to investigate the development of bone. Result : According to the findings, being exposed to nicotine led to an increase in the density of microvessels, but it had a detrimental effect on the flow of blood and the development of bones. In addition to this, it was found that the expression of bone morphogenetic protein (BMP)-2 in osteoblasts was lower than it had been in the past. In the process of distraction regeneration, ischemia and a low oxygen tension were both present, and the creation of cartilage islands on a consistent basis was a sign of both of these circumstances. Result: As a result of our investigation, we got to the realisation that nicotine consumption slows down the process of bone regeneration. We hypothesise that this takes place as a result of the fact that nicotine leads to ischemia and has an effect that is directly inhibitory on osteoblastic cells. It has been demonstrated that nicotine causes an increase in angiogenesis; however, this improvement is not adequate to compensate for the harmful effect of vasoconstriction caused by nicotine.

Correction to: Does the use of i-FACTOR bone graft affect bone healing in those undergoing periacetabular osteotomy (PAO) for developmental dysplasia of the hip (DDH)? A retrospective study

Correction to: Does the use of i-FACTOR bone graft affect bone healing in those undergoing periacetabular osteotomy (PAO) for developmental dysplasia of the hip (DDH)? A retrospective study

Does the use of i-FACTOR bone graft affect bone healing in those undergoing periacetabular osteotomy (PAO) for developmental dysplasia of the hip (DDH)? A retrospective study.

The aims of this study were to compare, in patients with and without the use of i-FACTOR bone graft during periacetabular osteotomy (PAO) surgery for developmental dysplasia of the hip (DDH), (i) bone healing at six-weeks post-operatively (ii) rate of complications. This was a retrospective review of case records. Participants were people aged 15-50 years undergoing rectus-sparing minimally invasive PAO surgery for DDH. Group 1: patients with i-FACTOR, Group 2: No i-FACTOR. The primary outcome was the rate of bone healing on radiographs at 6 weeks. The likelihood of bone healing was compared using logistic regression with Generalised Estimating Equations (GEE) and expressed as odds ratios (95% confidence intervals (CIs; P < 0.05)). The occurrence of complications was extracted from surgical records. The i-FACTOR group had 3-times greater odds of partial/full union than those without [adjusted odds ratio (95% CIs, P-value)]: [3.265 (1.032 to 10.330, P = 0.044)]. The i-FACTOR group had 89% partial/full union at 6-weeks, compared to 69% of the non-i-FACTOR group. Half of the patients had leaking of bone graft in the i-FACTOR group versus 10% in the non-i-FACTOR group, 26% of the i-FACTOR group and 12% of the non-i-FACTOR group had neuropraxia of the lateral femoral cutaneous nerve (LFCN). Complication rates were low, and similar between groups. However, the rate of LFCN neuropraxia and bone graft leakage was higher in the i-FACTOR. These findings should be confirmed in a future prospective randomised clinical trial and include outcomes such as pain and quality of life.

Influence on Implant Bone Healing of a Collagen Membrane Placed Subjacent the Sinus Mucosa-A Randomized Clinical Trial on Sinus Floor Elevation.

Background: Perforation of the sinus mucosa is quite a frequent complication that might occur during sinus floor elevation. The perforation is often protected with a collagen membrane to avoid the extrusion of graft particles within the sinus. However, this procedure might hinder the innate osteogenic potential of the sinus mucosa. Hence, the aim of the study was to evaluate the influence of a placement of a collagen membrane subjacent the Schneiderian membrane during sinus floor elevation on implant bone healing. Methods: Twenty volunteers took part in the trial. Ten were randomly included in the group that received a collagen membrane subjacent the sinus mucosa (Mb group), and ten did not receive the membrane (non-Mb group). A collagenated corticocancellous porcine bone was used to fill the elevated space. Six 6 months after the sinus floor elevation, a mini implant was placed transcrestally and retrieved after a further 3 months. Histological analyses were then performed on the full body of the mini implant as well as on its coronal and apical portions. Results: The new bone apposition proportion onto the implant surface was similar in the Mb and non-Mb groups, both in the apical and coronal portions of the mini implants. A lesser amount of graft was found in contact with the surface. New bone density around the mini implants were similar both in the apical and coronal portions. However, a statistically higher proportion of graft particles was found in the Mb group compared to the non-membrane group. Conclusions: The placement of a collagen membrane subjacent the sinus mucosa did not affect bone healing at implants and bone density.

Immune-instructive copolymer scaffolds using plant-derived nanoparticles to promote bone regeneration

BackgroundAge-driven immune signals cause a state of chronic low-grade inflammation and in consequence affect bone healing and cause challenges for clinicians when repairing critical-sized bone defects in elderly patients.MethodsPoly(l-lactide-co-ɛ-caprolactone) (PLCA) scaffolds are functionalized with plant-derived nanoparticles from potato, rhamnogalacturonan-I (RG-I), to investigate their ability to modulate inflammation in vitro in neutrophils and macrophages at gene and protein levels. The scaffolds’ early and late host response at gene, protein and histological levels is tested in vivo in a subcutaneous rat model and their potential to promote bone regeneration in an aged rodent was tested in a critical-sized calvaria bone defect. Significant differences were tested using one-way ANOVA, followed by a multiple-comparison Tukey’s test with a p value ≤ 0.05 considered significant.ResultsGene expressions revealed PLCA scaffold functionalized with plant-derived RG-I with a relatively higher amount of galactose than arabinose (potato dearabinated (PA)) to reduce the inflammatory state stimulated by bacterial LPS in neutrophils and macrophages in vitro. LPS-stimulated neutrophils show a significantly decreased intracellular accumulation of galectin-3 in the presence of PA functionalization compared to Control (unmodified PLCA scaffolds). The in vivo gene and protein expressions revealed comparable results to in vitro. The host response is modulated towards anti-inflammatory/ healing at early and late time points at gene and protein levels. A reduced foreign body reaction and fibrous capsule formation is observed when PLCA scaffolds functionalized with PA were implanted in vivo subcutaneously. PLCA scaffolds functionalized with PA modulated the cytokine and chemokine expressions in vivo during early and late inflammatory phases. PLCA scaffolds functionalized with PA implanted in calvaria defects of aged rats downregulating pro-inflammatory gene markers while promoting osteogenic markers after 2 weeks in vivo.ConclusionWe have shown that PLCA scaffolds functionalized with plant-derived RG-I with a relatively higher amount of galactose play a role in the modulation of inflammatory responses both in vitro and in vivo subcutaneously and promote the initiation of bone formation in a critical-sized bone defect of an aged rodent. Our study addresses the increasing demand in bone tissue engineering for immunomodulatory 3D scaffolds that promote osteogenesis and modulate immune responses.