Initial bone tissue reactions of hydroxyapatite/collagen-(3-glycidoxypropyl)trimethoxysilane injectable bone paste.

We have previously reported that a novel bioresorbable self-setting injectable bone paste composed of hydroxyapatite/collagen bone-like nanocomposite (HAp/Col) and (3-glycidoxypropyl)trimethoxysilane (GPTMS) was successfully prepared and was replaced with new bone within 3 months of implantation in defects created in porcine tibia. In this study, the HAp/Col-GPTMS paste was implanted into bone defects in rat tibiae to investigate the initial kinetics and bone tissue response. Even though more than 35% of GPTMS molecules should be eluted rapidly from directly injected pastes according to previously reported cell culture tests, in this study, energy-dispersive X-ray spectrometry did not detect Si (GPTMS) deposition in tissues surrounding the paste at 1 day postimplantation. Further, no abnormal inflammatory responses were observed in the surrounding tissues over the test period for both directly injected and prehardened pastes. Companying these observations with the results of the previous animal test (in which the paste was fully resorbed and was substituted with new bone), the eluted GPTMS resolved in no harm in vivo from the initial to final (completely resorbed) stages. Material resorption rates calculated from X-ray microcomputed tomography (µ-CT) images decreased with increasing in GPTMS concentration. Histological observations indicated that tartrate-resistant acid phosphatase (TRAP) active cells, (assumed to be osteoclasts), exist on the periphery of pastes. This result suggested that the paste was resorbed by osteoclasts in the same way as the HAp/Col. Since a good correlation was observed between TRAP active areas in histological sections and material resorption rate calculated from µ-CT, the TRAP activity coverage ratio offers the possibility to estimate the osteoclastic resorption ratio of materials, which are replaced with bone via bone remodeling process.

Engineering a 3-dimensional tissue construct with adipose-derived stem cells for healing bone defect: An ex vivo study with femur head.

The compatibility of bone graft substitutes (BGS) with mesenchymal stem cells (MSCs) is an important parameter to consider for their use in repairing bone defects as it eventually affects the clinical outcome. In the present study, a few commercially available BGS - ß-tricalcium phosphate (ß-TCP), calcium sulfate, gelatin sponge, and different forms of hydroxyapatite (HAP) were screened for their interactions with MSCs from adipose tissue (ADSCs). It was demonstrated that HAP block favorably supported ADSC viability, morphology, migration, and differentiation compared to other scaffolds. The results strongly suggest the importance of preclinical evaluation of bone scaffolds for their cellular compatibility. Furthermore, the bone regenerative potential of HAP block with ADSCs was evaluated in an ex vivo bone defect model developed using patient derived trabecular bone explants. The explants were cultured for 45 days in vitro and bone formation was assessed by expression of osteogenic genes, ALP secretion, and high resolution computed tomography. Our findings confirmed active bone repair process in ex vivo settings. Addition of ADSCs significantly accelerated the repair process and improved bone microarchitecture. This ex vivo bone defect model can emerge as a viable alternative to animal experimentation and also as a potent tool to evaluate patient specific bone therapeutics under controlled conditions.

Feasibility and Preliminary Efficacy of α-Calcium Sulfate Hemihydrate in Socket Preservation: Protocol for a Pilot Randomized Controlled Trial.

BACKGROUND: Tooth extraction procedures often lead to bone resorption, which can have adverse effects on the dimensions of the alveolar ridge. Research has shown that socket preservation techniques using bone graft substitutes can effectively minimize early bone loss in such cases. α-calcium sulfate hemihydrate (α-CSH) has garnered significant attention as a potential bone graft material due to its favorable properties, including osteoconductivity, angiogenic potential, and biocompatibility. Considering these facts, we developed a preliminary protocol for applying α-CSH in addressing alveolar bone loss following tooth extraction. OBJECTIVE: This research's general objective is to evaluate the feasibility and initial effectiveness of α-CSH as bone-inducing graft material for socket preservation after tooth extraction. METHODS: This preliminary clinical trial will involve 30 fresh extraction sockets from individuals aged 18-35 years. The participants will be divided into 2 groups: one group will receive α-CSH graft material after tooth extraction for socket preservation, while the other group will not receive any graft material. Throughout the study, the participants will be closely monitored for safety measures, which will include clinical examinations, radiographic imaging, and blood tests. Radiographic imaging will be used extensively to assist the progress of bone formation. RESULTS: The study commenced enrollment in August 2022 and is scheduled to conclude post assessments and analyses by the end of 2023. The results of the study are anticipated to be accessible in late 2024. CONCLUSIONS: This clinical study represents the initial investigation in humans to assess the feasibility and efficacy of α-CSH in alveolar bone regeneration. We hypothesize that the inclusion of α-CSH can greatly expedite the process of bone formation within fresh sockets, resulting in a swift restoration of bone height without the disadvantages associated with harvesting autogenous bone graft. TRIAL REGISTRATION: Indonesia Registry Center INA-D02FAHP; https://tinyurl.com/2jnf6n3s. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/49922.

A novel strategy for calcium magnesium phosphate/carboxymethyl chitosan composite bone cements with enhanced physicochemical properties, excellent cytocompatibility and osteogenic differentiation.

Artificial bone substitutes for bone repair and reconstruction still face enormous challenges. Previous studies have shown that calcium magnesium phosphate cements (CMPCs) possess an excellent bioactive surface, but its clinical application is restricted due to short setting time. This study aimed to develop new CMPC/carboxymethyl chitosan (CMCS) comg of mixed powders of active MgO, calcined MgO and calcium dihydrogen phosphate monohydrate. With this novel strategy, it can adjust the setting time and improve the compressive strength. The results confirmed that CMPC/CMCS composite bone cements were successfully developed with a controllable setting time (18-70 min) and high compressive strength (87 MPa). In addition, the composite bone cements could gradually degrade in PBS with weight loss up to 32% at 28 d. They also promoted the proliferation of pre-osteoblasts, and induced osteogenic differentiation. The findings indicate that CMPC/CMCS composite bone cements hold great promise as a new type of bone repair material in further and in-depth studies.

Development of a composite using calcined bone powder and silane cross-linked alginate as bone substitute material.

Calcined bone is an attractive natural material for use as a bone substitute because of its cost-effectiveness and high biocompatibility, which are comparable to that of synthetic hydroxyapatite. However, the calcination process has significantly weakened the mechanical properties. In this study, a composite of calcined bovine bone powder reinforced with silane cross-linked alginate was prepared to assess its biocompatibility, osteoconductivity, and mechanical compatibility as a bone substitute material. Culture studies with osteoblast-like cells (MC3T3-E1) showed no cytotoxicity toward the composite and exhibited general cell proliferative properties in its presence. In contrast, the composite reduced the alkaline phosphatase activity of osteoblasts but led to significant noncellular apatite deposition on the surface. In addition, quasi-static compression tests of the composite revealed mechanical properties comparable to those of human cancellous bone. The mechanical properties remained stable under wet conditions and did not deteriorate significantly even after 2 weeks of immersion in simulated body fluid at 37°C. The results show that this composite, composed of calcined bone powder and silane cross-linked alginate, is a promising bone substitute material with biocompatibility, osteoconductivity, and mechanical compatibility.

Effectiveness of synthetic versus autologous bone grafts in foot and ankle surgery: a systematic review and meta-analysis.

BACKGROUND: All orthopaedic procedures, comprising foot and ankle surgeries, seemed to show a positive trend, recently. Bone grafts are commonly employed to fix bone abnormalities resulting from trauma, disease, or other medical conditions. This study specifically focuses on reviewing the safety and efficacy of various bone substitutes used exclusively in foot and ankle surgeries, comparing them to autologous bone grafts. METHODS: The systematic search involved scanning electronic databases including PubMed, Scopus, Cochrane online library, and Web of Science, employing terms like 'Bone substitute,' 'synthetic bone graft,' 'Autograft,' and 'Ankle joint.' Inclusion criteria encompassed RCTs, case-control studies, and prospective/retrospective cohorts exploring different bone substitutes in foot and ankle surgeries. Meta-analysis was performed using R software, integrating odds ratios and 95% confidence intervals (CI). Cochrane's Q test assessed heterogeneity. RESULTS: This systematic review analyzed 8 articles involving a total of 894 patients. Out of these, 497 patients received synthetic bone grafts, while 397 patients received autologous bone grafts. Arthrodesis surgery was performed in five studies, and three studies used open reduction techniques. Among the synthetic bone grafts, three studies utilized a combination of recombinant human platelet-derived growth factor BB homodimer (rhPDGF-BB) and beta-tricalcium phosphate (ß-TCP) collagen, while four studies used hydroxyapatite compounds. One study did not provide details in this regard. The meta-analysis revealed similar findings in the occurrence of complications, as well as in both radiological and clinical evaluations, when contrasting autografts with synthetic bone grafts. CONCLUSION: Synthetic bone grafts show promise in achieving comparable outcomes in radiological, clinical, and quality-of-life aspects with fewer complications. However, additional research is necessary to identify the best scenarios for their use and to thoroughly confirm their effectiveness. LEVELS OF EVIDENCE: Level II.

In vitro and in vivo dissolution of biocompatible S59 glass scaffolds.

Fabrication of porous tissue-engineering scaffolds from bioactive glasses (BAG) is complicated by the tendency of BAG compositions to crystallize in thermal treatments during scaffold manufacture. Here, experimental biocompatible glass S59 (SiO2 59.7 wt%, Na2O 25.5 wt%, CaO 11.0 wt%, P2O5 2.5 wt%, B2O3 1.3 wt%), known to be resistant to crystallization, was used in sintering of glass granules (300-500 µm) into porous scaffolds. The dissolution behavior of the scaffolds was then studied in vivo in rabbit femurs and under continuous flow conditions in vitro (14 days in vitro/56 days in vivo). The scaffolds were osteoconductive in vivo, as bone could grow into the scaffold structure. Still, the scaffolds could not induce sufficiently rapid bone ingrowth to replace the strength lost due to dissolution. The scaffolds lost their structure and strength as the scaffold necks dissolved. In vitro, S59 dissolved congruently throughout the 14-day experiments, resulting in only a slight reaction layer formation. Manufacturing BAG scaffolds from S59 that retain their amorphous structure was thus possible. The relatively rapid and stable dissolution of the scaffold implies that the glass S59 may have the potential to be used in composite implants providing initial strength and stable, predictable release of ions over longer exposure times.

Developments in Alloplastic Bone Grafts and Barrier Membrane Biomaterials for Periodontal Guided Tissue and Bone Regeneration Therapy.

Periodontitis is a serious form of oral gum inflammation with recession of gingival soft tissue, destruction of the periodontal ligament, and absorption of alveolar bone. Management of periodontal tissue and bone destruction, along with the restoration of functionality and structural integrity, is not possible with conventional clinical therapy alone. Guided bone and tissue regeneration therapy employs an occlusive biodegradable barrier membrane and graft biomaterials to guide the formation of alveolar bone and tissues for periodontal restoration and regeneration. Amongst several grafting approaches, alloplastic grafts/biomaterials, either derived from natural sources, synthesization, or a combination of both, offer a wide variety of resources tailored to multiple needs. Examining several pertinent scientific databases (Web of Science, Scopus, PubMed, MEDLINE, and Cochrane Library) provided the foundation to cover the literature on synthetic graft materials and membranes, devoted to achieving periodontal tissue and bone regeneration. This discussion proceeds by highlighting potential grafting and barrier biomaterials, their characteristics, efficiency, regenerative ability, therapy outcomes, and advancements in periodontal guided regeneration therapy. Marketed and standardized quality products made of grafts and membrane biomaterials have been documented in this work. Conclusively, this paper illustrates the challenges, risk factors, and combination of biomaterials and drug delivery systems with which to reconstruct the hierarchical periodontium.

Concentrated growth factor and collagen as barrier materials in alveolar ridge preservation for posterior teeth: a prospective cohort study with one-year follow-up.

OBJECTIVES: This study aims to evaluate the efficacy of concentrated growth factor (CGF) membrane and collagen as barrier materials in sealing the alveolar socket in alveolar ridge preservation (ARP) in the posterior region during a one-year follow-up. METHODS: A total of 24 patients who underwent ARP in the posterior region were selected for inclusion and randomly assigned to the CGF group (12 cases) and Collagen group (12 cases). The patients in both groups underwent extraction of posterior teeth. The extraction sockets were filled with a bone substitute to the level of the pre-extraction buccal and lingual or palatal alveolar bone plates. The wounds in the CGF group were closed with a fabricated CGF overlaying the upper edge of the bone substitute material, whereas those in the Collagen group were closed with Bio-Oss Collagen. The implants were placed after 6 months. The evaluation was based on implant retention, re-grafting rate, and vertical and horizontal alveolar ridge bone volume changes measured by cone beam computed tomography (CBCT). Data were statistically analyzed using SPSS 28.0 software. RESULTS: No patient withdrew throughout the follow-up period. No implant failure and no severe peri-implant or mucosal soft tissue complications were observed. Six months after the operation, the degree of vertical alveolar ridge height resorption in the CGF group was lower than that in the Collagen group (P<0.05). There were no statistically difference between the groups at 1 year after the operation (P>0.05). The amount of bone reduction in horizontal alveolar ridge width showed no difference between the groups at 6 months and 1 year after surgery (P>0.05). CONCLUSIONS: CGF membrane and Bio-Oss Collagen as barrier materials for posterior ARP inhibited reduction in alveolar ridge bone mass.

Biological evaluation of critical bone defect regeneration using hydroxyapatite/ alginate composite granules.

PURPOSE: to evaluate biocompatibility and osteogenic potential of hydroxyapatite/alginate composite after its implantation on rat calvarian critical bone defect. METHODS: thirty adults male Wistar rats were randomly distributed into two groups: GHA - critical bone defect filled with hydroxyapatite/alginate composite granules (HA/Alg) and CG - critical bone defect without biomaterial; evaluated at biological points of 15, 45 and 120 days. RESULTS: the histomorphometrically analyses for GHA showed osteoid matrix deposition (OM) among the granules and towards the center of the defect in centripetal direction throughout the study, with evident new bone formation at 120 days, resulting in filling 4/5 of the initial bone defect. For CG, this finding was restricted to the edges of the bone margins and formation of connective tissue on the residual area was found in all biological points. Inflammatory response on GHA was chronic granulomatous type, discrete and regressive for all biological points. Throughout the study, the CG presented mononuclear inflammatory infiltrate diffuse and regressive. Histomorphometry analyses showed that OM percentage was evident for GHA group when compared to CG group in all analyzed periods (p > 0.05). CONCLUSIONS: the biomaterial evaluated at this study showed to be biocompatible, bioactive, osteoconductive and biodegradable synchronously with bone formation.

Percutaneous microwave ablation, perfusion, and reconstruction combined with a synthetic bone substitute in symptomatic bone cysts: a minimum of 26 months follow-up.

PURPOSE: The objective was to describe the technique and clinical outcome of microwave thermal ablation (MWA) and perfusion combined with synthetic bone substitutes in treating unicameral bone cysts (UBCs) in adolescents. MATERIALS AND METHODS: A total of 14 consecutive patients were enrolled by percutaneous MWA and saline irrigation combined with synthetic bone substitutes. Clinical follow-up included the assessment of pain, swelling, and functional mobility. Radiological parameters included tumor volume, physis-cyst distance, cortical thickness of the thinnest cortical bone, and the Modified Neer classification system. RESULTS: The mean follow-up was 28.9 months (26-52 months). All UBCs were primary, and all patients underwent the MWA, saline perfusion, and reconstruction combined with a synthetic bone substitute session, except for one patient (7.1%) who required a second session. All patients had good clinical results at the final follow-up. Satisfactory cyst healing was achieved in 13 cases according to radiological parameters. Tumor volume decreased from a mean of 49.7 cm3 before surgery treatment to 13.9 cm3 at the final follow-up (p < 0.01). The physis-cyst distance increased from a mean of 3.17-4.83 cm at the final follow-up (p < 0.01). Cortical thickness improved from a mean of 1.1 mm to 2.0 mm at the final follow-up (p < 0.01). According to the proposed radiological criteria, our results were considered successful (Grading I and II) in 13 patients (92.9%) at the final follow-up. CONCLUSION: Percutaneous microwave ablation combined with a bone graft substitute is a minimally invasive, effective, safe, and cost-effective approach to treating primary bone cysts in the limbs of adolescents.

Maxillary Sinus Augmentation with Anorganic Bovine Bone Mineral of Different Particle Sizes: A Split-Mouth Study with Histomorphometric, Radiographic, and Clinical Analyses.

PURPOSE: The aim of the present study was to compare the histomorphometrically evaluated new bone formation (NB), the radiographically measured graft stability, and the clinical implant outcome for maxillary sinus augmentation grafted with deproteinized bovine bone mineral (DBBM) with either small (Bio-Oss-S, Geistlich) or large (Bio-Oss-L, Geistlich) particles. MATERIALS AND METHODS: Using a split-mouth study design, bilateral maxillary sinus augmentation was performed in 13 patients either with Bio-Oss-S particles (0.25 to 1 mm) or Bio-Oss-L particles (1 to 2 mm). After a healing period of 6 months, bone biopsies were axially retrieved in the molar region for histologic/histomorphometric analysis of NB, including subsequent staged implant placement. To determine graft stability, the maxillary sinus augmentation vertical graft heights were radiographically measured immediately after sinus augmentation, at implant placement, and at the 2- and 4-year post-augmentation follow-ups. In addition, the clinical implant-prosthodontic outcome (survival/ success/marginal bone loss) was assessed at 1 and 3 years post-loading. RESULTS: A total of 22 sinuses from 11 patients with split-mouth evaluation were ultimately available for data and statistical analysis. Histomorphometric analysis of the axially retrieved bone biopsies revealed the presence of NB (S: 25.5% ± 7.0% vs L: 23.6% ± 11.9%; P = .640), residual graft particles (S: 19.6% ± 9.2% vs L: 17.5% ± 6.3%; P = .365) as well as connective tissue (S: 54.9% ± 9.2% vs L: 58.9% ± 12.5%; P = .283), without significant differences between the use of small (Bio-Oss-S) and large (Bio-Oss-L) particles. However, there was significantly (P = .021) higher bone-to-graft contact (BGC) for the small-particle graft sites (27.9% ± 14.8%) compared to the large-particle graft sites (19.9% ± 12.9%), representing a significantly higher osteoconductivity. Both particle sizes showed significant (P < .01) vertical graft height reduction over time (4 years) of about 10%, with predominant graft reduction in the time period between sinus augmentation and implant placement compared to any follow-up periods after implant placement. At the 3-year post-loading implant evaluation, all implants and prostheses survived (100%), and the peri-implant marginal bone loss (S: 0.52 ± 0.19 mm; L: 0.48 ± 0.15 mm) as well as the peri-implant health conditions (S: 87.5%, L:81.2%) did not differ between implants inserted with the two different xenograft particles used. CONCLUSIONS: The use of small and large bovine xenograft particles for maxillary sinus augmentation provides for comparable bone formation, ensuring stable graft dimensions combined with high implant success and healthy peri-implant conditions. However, small particle size resulted in a higher BGC, providing for higher osteoconductivity than with the larger particle size.

Titanium-doped phosphate glasses containing zinc and strontium applied in bone regeneration.

Phosphate bioactive glass has been studied for its advanced biodegradability and active ion release capability. Our previous research found that phosphate glass containing (P2O5)-(Na2O)-(TiO2)-(CaO)-(SrO) or (ZnO) showed good biocompatibility with MG63 and hMSCs. This study further investigated the application of 5 mol% zinc oxide or 17.5 mol% strontium oxide in titanium-doped phosphate glass for bone tissue engineering. Ti-Ca-Na-Phosphate glasses, incorporating 5% zinc oxide or 17.5% strontium oxide, were made with melting quenching technology. The pre-osteoblast cell line MC3T3-E1 was cultured for indirect contact tests with graded diluted phosphate glass extractions and for direct contact tests by seeding cells on glass disks. The cell viability and cytotoxicity were analysed in vitro over 7 days. In vivo studies utilized the tibial defect model with or without glass implants. The micro-CT analysis was performed after surgery and then at 2, 6, and 12 weeks. Extractions from both zinc and strontium phosphate glasses showed no negative impact on MC3T3-E1 cell viability. Notably, non-diluted Zn-Ti-Ca-Na-phosphate glass extracts significantly increased cell viability by 116.8% (P < 0.01). Furthermore, MC3T3-E1 cells cultured with phosphate glass disks exhibited no increase in LDH release compared with the control group. Micro-CT images revealed that, over 12 weeks, both zinc-doped and strontium-doped phosphate glasses demonstrated good bone incorporation and longevity compared to the no-implant control. Titanium-doped phosphate glasses containing 5 mol% zinc oxide, or 17.5 mol% strontium oxide have promising application potential for bone regeneration research.

[Preparation and in vivo osteogenesis of acellular dermal matrix/dicalcium phosphate composite scaffold for bone repair].

Objective: To investigate the physicochemical properties, osteogenic properties, and osteogenic ability in rabbit model of femoral condylar defect of acellular dermal matrix (ADM)/dicalcium phosphate (DCP) composite scaffold. Methods: ADM/DCP composite scaffolds were prepared by microfibril technique, and the acellular effect of ADM/DCP composite scaffolds was detected by DNA residue, fat content, and α-1，3-galactosyle (α-Gal) epitopes; the microstructure of scaffolds was characterized by field emission scanning electron microscopy and mercury porosimetry; X-ray diffraction was used to analyze the change of crystal form of scaffold; the solubility of scaffolds was used to detect the pH value and calcium ion content of the solution; the mineralization experiment in vitro was used to observe the surface mineralization. Twelve healthy male New Zealand white rabbits were selected to prepare the femoral condylar defect models, and the left and right defects were implanted with ADM/DCP composite scaffold (experimental group) and skeletal gold ® artificial bone repair material (control group), respectively. Gross observation was performed at 6 and 12 weeks after operation; Micro-CT was used to detect and quantitatively analyze the related indicators [bone volume (BV), bone volume/tissue volume (BV/TV), bone surface/bone volume (BS/BV), trabecular thickness (Tb.Th), trabecular number (Tb.N), trabecular separation (Tb.Sp), bone mineral density (BMD)], and HE staining and Masson staining were performed to observe the repair of bone defects and the maturation of bone matrix. Results: Gross observation showed that the ADM/DCP composite scaffold was a white spongy solid. Compared with ADM, ADM/DCP composite scaffolds showed a significant decrease in DNA residue, fat content, and α-Gal antigen content ( P<0.05). Field emission scanning electron microscopy showed that the ADM/DCP composite scaffold had a porous structure, and DCP particles were attached to the porcine dermal fibers. The porosity of the ADM/DCP composite scaffold was 76.32%±1.63% measured by mercury porosimetry. X-ray diffraction analysis showed that the crystalline phase of DCP in the ADM/DCP composite scaffolds remained intact. Mineralization results in vitro showed that the hydroxyapatite layer of ADM/DCP composite scaffolds was basically mature. The repair experiment of rabbit femoral condyle defect showed that the incision healed completely after operation without callus or osteophyte. Micro-CT showed that bone healing was complete and a large amount of new bone tissue was generated in the defect site of the two groups, and there was no difference in density between the defect site and the surrounding bone tissue, and the osteogenic properties of the two groups were equivalent. There was no significant difference in BV, BV/TV, BS/BV, Tb.Th, Tb.N, and BMD between the two groups ( P>0.05), except that the Tb.Sp in the experimental group was significantly higher than that in the control group ( P<0.05). At 6 and 12 weeks after operation, HE staining and Masson staining showed that the new bone and autogenous bone fused well in both groups, and the bone tissue tended to be mature. Conclusion: The ADM/DCP composite scaffold has good biocompatibility and osteogenic ability similar to the artificial bone material in repairing rabbit femoral condylar defects. It is a new scaffold material with potential in the field of bone repair.

Effect of mineralized dentin matrix on the prognosis of bone defect and retained root after coronectomy.

OBJECTIVE: To investigate the impact of mineralized dentin matrix (MDM) on the prognosis on bone regeneration and migration of retained roots after coronectomy. MATERIALS AND METHODS: Patients were divided into three groups based on the type of bone graft after coronectomy: Group C (n = 20, collagen), Group T (n = 20, tricalcium phosphate (TCP) + collagen), and Group D (n = 20, MDM + collagen). CBCT scans, conducted immediately and 6 months after surgery, were analyzed using digital software. Primary outcomes, including changes in bone defect depth and retained root migration distance, were evaluated 6 months after surgery. RESULTS: After 6 months, both Groups D and T exhibited greater reduction of the bone defect and lesser retained root migration than Group C (p < 0.001). Group D had greater regenerated bone volume in the distal 2 mm (73 mm3 vs. 57 mm3, p = 0.011) and lesser root migration (2.18 mm vs. 2.96 mm, p < 0.001) than Group T. The proportion of completely bone embedded retained roots was also greater in Group D than in Group C (70.0% vs. 42.1%, p = 0.003). CONCLUSIONS: MDM is an appropriate graft material for improving bone defect healing and reducing retained root migration after coronectomy. CLINICAL RELEVANCE: MDM is an autogenous material prepared chairside, which can significantly improve bone healing and reduce the risk of retained root re-eruption. MDM holds promise as a routine bone substitute material after M3M coronectomy.

Progress of research on the surface functionalization of tantalum and porous tantalum in bone tissue engineering.

Tantalum and porous tantalum are ideal materials for making orthopedic implants due to their stable chemical properties and excellent biocompatibility. However, their utilization is still affected by loosening, infection, and peripheral inflammatory reactions, which sometimes ultimately lead to implant removal. An ideal bone implant should have exceptional biological activity, which can improve the surrounding biological microenvironment to enhance bone repair. Recent advances in surface functionalization have produced various strategies for developing compatibility between either of the two materials and their respective microenvironments. This review provides a systematic overview of state-of-the-art strategies for conferring biological functions to tantalum and porous tantalum implants. Furthermore, the review describes methods for preparing active surfaces and different bioactive substances that are used, summarizing their functions. Finally, this review discusses current challenges in the development of optimal bone implant materials.

The effect of a barrier membrane on the incorporation of deproteinized bovine bone mineral (DBBM) in experimental defects at the time of early implant placement. A preclinical study.

OBJECTIVES: This study aimed to assess membrane use with a bone substitute graft for guided bone regeneration (GBR) in experimental dehiscence defects. MATERIALS AND METHODS: Maxillary second incisors (I2) in 9 dogs were extracted. Six weeks later, implants were inserted and experimental dehiscence defects (5 × 3 mm) created on the buccal aspect. The defects and surrounding bone were grafted with deproteinized bovine bone mineral. One side (test) was covered with a resorbable collagen membrane whereas the contralateral side (control) was not. After 6 weeks, histomorphometrical analysis was performed to evaluate: (a) first bone-to-implant contact (fBIC), (b) buccal bone thickness at 1 mm increments from implant shoulder, (c) regenerated area (RA), (d) area and percentages of new bone (B), bone substitute (BS) and mineralized tissue (MT). RESULTS: The histological appearance was similar between test and control sites. At central and lateral sections, there were no differences between groups for fBIC, buccal bone thickness, RA, BS, B, %B, MT and %MT. At central sections, membrane use favoured more %BS and %MT (p = 0.052). There was significantly more B, %B and MT at lateral compared to central sections. CONCLUSIONS: Membrane use tended to retain more bone substitute, but had no effect on new bone ingrowth. Lateral sections showed significantly more bone ingrowth and mineralized tissue compared to central sections, confirming that new bone ingrowth takes place mainly from the lateral walls of the defect. CLINICAL RELEVANCE: Preclinical research to clarify the dynamics of bone regeneration in GBR procedures is relevant in clinical practice.

Composite bone graft of CaO-MgO-SiO2 glass-ceramics and CaSO4 ceramics for boosting bone formation rate.

This study develops a composite bone graft of CaO-MgO-SiO2 glass-ceramic and CaSO4 [abbreviated as (CMS)3-x(CS)x] via the sponge replication technique with weight fractions of x = 0, 1, 1.5, 2, and 3. The (CMS)1.5(CS)1.5 composite displays a superior degradability and, a suitable compressive strength of ∼3 MPa, and excellent cell proliferation and differentiation. The in vivo rat femur test in the hybrid-pore (CMS)1.5(CS)1.5 composite granules achieves a higher rate of bone formation, which is ∼2.7 times better than that of the commercial HAP/ß-TCP at 12 weeks. Improved expressions of osteocyte and mature osteocyte marker genes, namely (Spp1, Dmp1, and Fgf23), were observed in the (CMS)1.5(CS)1.5 group, indicating a faster differentiation into mature bone tissue. The ions release of (CMS)1.5(CS)1.5 through the ERK1/2 signaling pathway promotes osteogenic differentiation. The high bone generation rate can be attributed to faster active ions release and modified surface topography. This work highlights an excellent bone graft candidate for clinical applications in orthopedic surgery.

Performance of a multiphase bioactive socket plug with a barrier function for alveolar ridge preservation.

The natural healing process of extraction socket and traditional socket plug material could not prevent buccal bone wall resorption and down growth of epithelium from the socket orifice. A multiphase bioactive socket plug (BP) is designed to overcome the natural healing process by maintaining the three-dimensional (3D) volume of extraction sockets, particularly in sockets with wall defects, and later provide sufficient alveolar bone volume for implant placement. The study aimed to fabricate and evaluate the physical, chemical, and biological performance of BPin vitro. The BP was fabricated through freeze-drying and layer-by-layer assembly, comprised of a base serving as a scaffold, a central portion for promoting bone regeneration, an upper buccal portion for maintaining alveolar socket dimension with a covering collagen membrane (Memb) on the top and upper buccal surface to prevent soft tissue infiltration. The BP as the experimental group and a pure collagen plug (CP) as the control group were investigated and compared. Radiograph, scanning electron microscopy, and energy-dispersive spectroscopy mapping confirmed that the four-part BP was successfully assembled and fabricated. Swelling rate analysis indicated that BP, CP, and Memb reached swelling equilibrium within 1 hour. BP exhibited a high remaining weight percentage in collagenase solution (68.81 ± 2.21% on day 90) and sustained calcium ion release, reaching the maximum 0.13 ± 0.04 mmol l-1on day 14. In biological assays, BP exhibited excellent cell proliferation (The OD value increased from 0.02 on day 1 to 0.23 on day 21.). The BP group exhibited higher alkaline phosphatase activity and osteocalcin content than the CP group within 21 days. Memb and BP exhibited outstanding barrier function, as evidenced by Hematoxylin and eosin staining. In summary, the multiphase bioactive socket plug represents a promising scaffold for alveolar ridge preservation application.

Hydroxyapatite synthesis and characterization from waste animal bones and natural sources for biomedical applications.

Hydroxyapatites (HAps) synthesized from waste animal bones have recently gained attention due to their outstanding properties. This is because there is a need to fabricate scaffolds with desirable mechanical strength, ability to withstand high temperatures, and insoluble in solvents such as water, acetone, ethanol, and isopropyl alcohol. This study is an extensive summary of many articles on the routes of synthesis/preparation of HAp, and the optimum processing parameter, and the biomedical application areas, such as: drug administration, dental implants, bone tissue engineering, orthopedic implant coatings, and tissue regeneration/wound healing. A broad catalog of the synthesis methods (and combination methods), temperature/time, shape/size, and the calcium-to-phosphorous (Ca/P) value of diverse waste animal bone sources were reported. The alkaline hydrolysis method is proposed to be suitable for synthesizing HAp from natural sources due to the technique's ability to produce intrinsic HAp. The method is also preferred to the calcination method owing to the phase transformation that takes place at high temperatures during calcinations. However, calcinations aid in removing impurities and germs during heating at high temperatures. When compared to calcination technique, alkaline hydrolysis method results in crystalline HAp; the higher degree of crystallinity is disadvantageous to HAp bioactivity. In addition, the standardization and removal of impurities and contaminants, thorough biocompatibility to ensure clinical safety of the HAp to the human body, and improvement of the mechanical strength and toughness to match specific requirements for the various biomedical applications are the important areas for future studies.