Bone Replacement Materials and Techniques Used for Achieving Vertical Alveolar Bone Augmentation

The Inlay Technique in Alveolar Ridge Augmentation: A Systematic Review

Background/Objectives: Vertical ridge augmentation remains a critical challenge in implant dentistry for addressing inadequate alveolar bone height. The inlay technique, or sandwich osteotomy, has gained attention for its potential to improve graft vascularization and predictability. This systematic review aimed to evaluate the clinical outcomes of the inlay technique. Methods: A systematic search was conducted in Cochrane Library and Medline databases for studies published from 2015 to 2025 to capture the most recent studies and advancements specifically focusing on the inlay technique. Inclusion criteria encompassed observational and interventional studies, including randomized controlled trials (RCTs) and cohort and case series with a focus on outcomes related to the inlay technique. Key outcomes were extracted and analyzed, including implant survival rates, MBL, vertical bone gain, and surgical complications. Results: Eleven studies involving 352 patients and more than 612 implants were included, with a mean follow-up of 2.27 ± 2.69 years (range: 4 months to 8 years). The implant survival rates ranged from 84.5% to 100%. Mean vertical bone gain varied from 2.69 to 4.4 mm. Complications were fewer with the inlay technique compared to onlay and other grafting methods, with significantly reduced graft-related failures and soft tissue issues. Conclusions: The inlay technique shows good vertical bone augmentation with high implant survival rates and fewer complications compared to other reconstructive techniques. Longer follow-up studies are needed to support its value in managing vertically deficient ridges. Moreover, further studies with extended follow-up are required to evaluate long-term marginal bone loss.

Tomographic and Electron Microscopy Description of Two Bone-Substitute Xenografts for the Preservation of Dental Alveoli

After tooth extraction, bone levels in the alveoli decrease. Using a bone substitute can help minimize this bone loss. The substitute can be sourced from a human or animal donor or synthetically prepared. In this study, we aimed to address the following PICOS question: In patients needing dental alveolar preservation for implant placement, how does alveolar preservation using a bovine hydroxyapatite bone xenograft with collagen compare to a xenograft without collagen in terms of changes in alveolar height and width, bone density, and the characteristics of the bone tissue observed in biopsies taken at 6 months? We evaluated two xenograft-type bone substitutes for preserving post-extraction dental sockets using tomography and microscopy to answer that question. A total of 18 dental alveoli were studied: 11 preserved with a xenograft composed of apatite (InterOss) and 7 with a xenograft composed of apatite-collagen (InterOss Collagen). Tomographic controls were performed at 1 and 6 months, and microscopic studies were performed on 13 samples. The biopsies were examined with scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). A Multivariate Analysis of Variance (MANOVA) was conducted in the statistical analysis, revealing a significant increase in bone density over time (p = 0.04). Specifically, bone density increased from an average of 526.14 HU at 30 days to 721.96 HU at 60 days in collagen-free samples. However, no statistically significant differences in height or width were found between groups. The MANOVA results indicated that the overall model had a low predictive ability for height, width, and density variables (R-squared values were low), likely due to sample size limitations and the complexity of bone tissue dynamics. On the other hand, FTIR analysis revealed the presence of phosphate groups, carbonates, and amides I, II, and III, indicative of inorganic (hydroxyapatite) and organic (type I collagen) materials in the xenografts. TGA and DSC showed high thermal stability, with minimal mass loss below 150 °C. Finally, both xenografts were influential in alveolar bone regeneration after extraction without significant differences. The trend of increasing collagen density suggests an effect that requires further investigation. However, it is recommended that the sample size be increased to enhance the validity of the results.

Long-term effectiveness of UV functionalised short (≤ 6 mm) dental implants placed in the posterior segments of the atrophied maxilla: controlled case series

This study evaluated long-term effectiveness UV functionalised short implants (≤ 6 mm) placed in the posterior segments of the atrophied maxilla. The study included 47 patients from 2018 to 2023 (aged 27 to 56 years, 24 women and 23 men) without any systemic diseases, with unilateral/bilateral missing teeth and vertical atrophy of the posterior maxillary area. Total installed were 64 short UV-functionalized implants and 62 standard implants over 10 mm in length in segments maxilla with sufficient bone parameters. Clinical, laboratory and cone beam computed tomography (CBCT) methods were used to plan implant therapy. The clinical indices included the following parameters: ISQ, MBL, OHIP-G scale. For short implants, the median ISQ at placement was 62.2 for primary stability and the median ISQ at 5 months was 69.6 ISQ. For standard implant, the mean ISQ at placement was 64.3 ISQ, and ISQ after 5 months was 71.6 ISQ. After 6 months mean MBL short implants 0.87 mm, after 1 year 1.13 mm, after 5 years was 1.48 mm. After 6 months mean MBL standard implants 0.84 mm, after 1 year 1.24 mm, after 5 years was 1.58 mm. Mean OHIP-G scores-patients satisfaction with the implant at 4.8 ± 0.3, satisfaction with the operation 4.6 ± 0.4; satisfaction with prosthetics 4.7 ± 0.5. Cumulative success rate 5 years short implants was 96.7%, standard implants was 97.4%, and prosthesis cumulative survival rate was 97.2%. Short ultraviolet functionalized implants used in the posterior resorbed segment of maxilla have been shown to be a reliable alternative to sinus lift, demonstrating fewer complications, reduction in the number of additional surgical interventions and showed satisfactory long-term survival.

The efficiency of two different synthetic bone graft materials on alveolar ridge preservation after tooth extraction: a split-mouth study

BACKGROUND

Alveolar Bone loss occurs frequently during the first six months after tooth extraction. Various studies have proposed different methods to reduce as much as possible the atrophy of the alveolar ridge after tooth extraction. Filling the socket with biomaterials after extraction can reduce the resorption of the alveolar ridge. We compared the height of the alveolar process at the mesial and distal aspects of the extraction site and the resorption rate was calculated after the application of HA/β-TCP or synthetic co-polymer polyglycolic - polylactic acid PLGA mixed with blood to prevent socket resorption immediately and after tooth extraction.

METHODS

The study was conducted on 24 extraction sockets of impacted mandibular third molars bilaterally, vertically, and completely covered, with a thin bony layer. HA/β-TCP was inserted into 12 of the dental sockets immediately after extraction, and the synthetic polymer PLGA was inserted into 12 of the dental sockets. All sockets were covered completely with a full-thickness envelope flap. Follow-up was performed for one year after extraction, using radiographs and stents for the vertical alveolar ridge measurements.

RESULTS

The mean resorption rate in the HA/β-TCP and PLGA groups was ± 1.23 mm and ± 0.1 mm, respectively. A minimal alveolar bone height reduction of HA/β-TCP was observed after 9 months, the reduction showed a slight decrease to 0.93 mm, while this rate was 0.04 mm after 9 months in the PLGA group. Moreover, the bone height was maintained after three months, indicating a good HA/β-TCP graft performance in preserving alveolar bone (1.04 mm) while this rate was (0.04 mm) for PLGA.

CONCLUSION

The PLGA graft demonstrated adequate safety and efficacy in dental socket preservation following tooth extraction. However, HA/β-TCP causes greater resorption at augmented sites than PLGA, which clinicians should consider during treatment planning.

Periodontists and stem cell-based therapy for alveolar bone regeneration: A national survey

BACKGROUND

Stem cell-based therapy for bone regeneration has received attention in medical settings but has not yet been used in clinical practice for treating alveolar bone defects. The objectives of this study were to explore whether periodontists had heard about this approach, and if so how, how interested they were to learn about it, which attitudes and behavioral intentions they had related to using stem cell-based grafting, and what they would like to know before using this approach.

METHODS

Anonymous survey data were collected from 481 members of the American Academy of Periodontology (response rate: 19.41%).

RESULTS

Responses showed 35.3% had heard about stem cell-based therapy, mostly from publications (9.6%) and meetings (8.3%); 76.1% wanted to learn about it through in-person continuing education (CE) courses, 68.6% in online CE courses, and 57.1% from manuals; 73% considered this approach promising; and 54.9% preferred it to traditional approaches. It was important to them that it would result in more bone volume (93%), better bone quality (90.4%), and accelerated healing (83.2%). Also, 60.1% considered it likely/very likely that they would adopt this approach, 54% that patients would prefer it, and 62.1% that it would benefit their practice. When asked what they would like to know about this approach, information about short- and long-term outcomes, cost, and logistical considerations were most frequently named.

CONCLUSIONS

These findings provide the basis to develop educational interventions for periodontists about this novel approach and inform future research activities aimed to translate this approach to clinical practice.

Application of modified porcine xenograft by collagen coating in the veterinary field: pre-clinical and clinical evaluations

Introduction

This study aimed to identify a collagen-coating method that does not affect the physicochemical properties of bone graft material. Based on this, we developed a collagen-coated porcine xenograft and applied it to dogs to validate its effectiveness.

Methods

Xenografts and collagen were derived from porcine, and the collagen coating was performed through N-ethyl-N'-(3- (dimethylamino)propyl) carbodiimide/N-hydroxysuccinimide (EDC/NHS) activation. The physicochemical characteristics of the developed bone graft material were verified through field emission scanning electron microscope (FE-SEM), brunauer emmett teller (BET), attenuated total reflectance-fourier transform infrared (ATR-FTIR), and water absorption test. Subsequently, the biocompatibility and bone healing effects were assessed using a rat calvarial defect model.

Results

The physicochemical test results confirmed that collagen coating increased bone graft materials' surface roughness and fluid absorption but did not affect their porous structure. In vivo evaluations revealed that collagen coating had no adverse impact on the bone healing effect of bone graft materials. After confirming the biocompatibility and effectiveness, we applied the bone graft materials in two orthopedic cases and one dental case. Notably, successful fracture healing was observed in both orthopedic cases. In the dental case, successful bone regeneration was achieved without any loss of alveolar bone.

Discussion

This study demonstrated that porcine bone graft material promotes bone healing in dogs with its hemostatic and cohesive effects resulting from the collagen coating. Bone graft materials with enhanced biocompatibility through collagen coating are expected to be widely used in veterinary clinical practice.

Biological Properties and Medical Applications of Carbonate Apatite: A Systematic Review

Bone defects represent an everyday challenge for clinicians who work in the fields of orthopedic surgery, maxillofacial and oral surgery, otorhinolaryngology, and dental implantology. Various bone substitutes have been developed and utilized, according to the needs of bone reconstructive surgery. Carbonate apatite has gained popularity in recent years, due to its excellent tissue behavior and osteoconductive potential. This systematic review aims to evaluate the role of carbonate apatite in bone reconstructive surgery and tissue engineering, analyze its advantages and limitations, and suggest further directions for research and development. The Web of Science, PubMed, and Scopus electronic databases were searched for relevant review articles, published from January 2014 to 21 July 2023. The study was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Eighteen studies were included in the present review. The biological properties and medical applications of carbonate apatite (CO3Ap) are discussed and evaluated. The majority of articles demonstrated that CO3Ap has excellent biocompatibility, resorbability, and osteoconductivity. Furthermore, it resembles bone tissue and causes minimal immunological reactions. Therefore, it may be successfully utilized in various medical applications, such as bone substitution, scaffolding, implant coating, drug delivery, and tissue engineering.

Volume change after maxillary sinus floor elevation with apatite carbonate and octacalcium phosphate

PURPOSE

Maxillary molars have low alveolar bone height diameter due to the presence of the maxillary sinus; thus, a sinus lift may be required in some cases. Changes in the volume of bone substitutes can affect the success of implant therapy. Therefore, this study aimed to compare the changes in the volume of two different bone substitutes-one based on carbonate apatite and the other on octacalcium phosphate-used in maxillary sinus floor elevation.

METHODS

Nineteen patients and 20 sites requiring maxillary sinus floor elevation were included in the study. Digital Imaging and Communications in Medicine data for each patient obtained preoperatively and immediately and 6 months postoperatively were used to measure the volume of the bone grafting material using a three-dimensional image analysis software. The immediate postoperative volume of octacalcium phosphate was 95.3775 mm3 per piece of grafting material used. It was multiplied by the number of pieces used and converted to mL to determine the immediate postoperative volume.

RESULTS

The mean resorption values of carbonate apatite and octacalcium phosphate were 12.7 ± 3.6% and 17.3 ± 3.9%, respectively. A significant difference in the amount of resorption of the two bone replacement materials was observed (P = 0.04).

CONCLUSIONS

The results of this study indicate that both bone substitute materials tend to resorb. The two bone grafting materials that are currently medically approved in Japan have not been in the market for a long time, and their long-term prognosis has not yet been reported. Further clinical data are warranted.

Osteogenic human MSC-derived extracellular vesicles regulate MSC activity and osteogenic differentiation and promote bone regeneration in a rat calvarial defect model

BACKGROUND

There is growing evidence that extracellular vesicles (EVs) play a crucial role in the paracrine mechanisms of transplanted human mesenchymal stem cells (hMSCs). Little is known, however, about the influence of microenvironmental stimuli on the osteogenic effects of EVs. This study aimed to investigate the properties and functions of EVs derived from undifferentiated hMSC (Naïve-EVs) and hMSC during the early stage of osteogenesis (Osteo-EVs). A further aim was to assess the osteoinductive potential of Osteo-EVs for bone regeneration in rat calvarial defects.

METHODS

EVs from both groups were isolated using size-exclusion chromatography and characterized by size distribution, morphology, flow cytometry analysis and proteome profiling. The effects of EVs (10 µg/ml) on the proliferation, migration, and osteogenic differentiation of cultured hMSC were evaluated. Osteo-EVs (50 µg) or serum-free medium (SFM, control) were combined with collagen membrane scaffold (MEM) to repair critical-sized calvarial bone defects in male Lewis rats and the efficacy was assessed using µCT, histology and histomorphometry.

RESULTS

Although Osteo- and Naïve-EVs have similar characteristics, proteomic analysis revealed an enrichment of bone-related proteins in Osteo-EVs. Both groups enhance cultured hMSC proliferation and migration, but Osteo-EVs demonstrate greater efficacy in promoting in vitro osteogenic differentiation, as evidenced by increased expression of osteogenesis-related genes, and higher calcium deposition. In rat calvarial defects, MEM with Osteo-EVs led to greater and more consistent bone regeneration than MEM loaded with SFM.

CONCLUSIONS

This study discloses differences in the protein profile and functional effects of EVs obtained from naïve hMSC and hMSC during the early stage of osteogenesis, using different methods. The significant protein profile and cellular function of EVs derived from hMSC during the early stage of osteogenesis were further verified by a calvarial bone defect model, emphasizing the importance of using differentiated MSC to produce EVs for bone therapeutics.

Comparison of vertical bone resorption following various types of autologous block bone grafts

BACKGROUND

This study aims to measure and compare the differences in vertical bone resorption after vertical augmentation using different types of autologous block bone.

METHODS

Data were collected from 38 patients who had undergone vertical ridge augmentation using an autologous block bone before implant insertion. The patients were divided into three groups based on the donor sites: ramus bone (RB), chin bone (CB), and iliac crestal bone (IB).

RESULTS

The surgical outcome of the augmentation was evaluated at the follow-up periods up to 60 months. In 38 patients, the mean amount of vertical bone gain was 8.36 ± 1.51 mm in the IB group, followed by the RB group (4.17 ± 1.31 mm) and the CB group (3.44 ± 1.08 mm). There is a significant difference in vertical bone resorption between the groups (p < 0.001), and the RB group demonstrated significantly lower resorption than the CB and IB groups (p = 0.011 and p < 0.001, respectively). The most common postoperative complications included neurosensory disturbance in the CB graft and gait disturbance in the IB graft. Out of the 92 implants inserted after augmentation, four implants were lost during the study period, resulting in an implant success rate of 95.65%.

CONCLUSIONS

The RB graft might be the most suitable option for vertical augmentation in terms of maintaining postoperative vertical height and reducing morbidity, although the initial gain was greater with the IB graft compared to other block bones.

Use of Injectable Platelet-Rich Fibrin Accompanied by Bone Graft in Socket Endurance: A Radiographic and Histological Study

Background Ridge preservation became a crucial dental health issue and strategy to keep away from ridge defacement after post-tooth loss. The recent scientific evolution of platelet-rich fibrin (PRF) comprises a parenteral formulation of PRF. The combined allograft for socket preservation gives benefits. In this study, bone allografts, demineralized freeze-dried bone allografts (DFDBA) and freeze-dried bone allografts (FDBA) are used in a 30:70 ratio alone or in combination with injectable PRF (I-PRF) for socket preservation. Methods This study is a radiographic and histological examination conducted on 60 participants aged between 19-65 years. Participating patients agreed voluntarily that they would not bear any fixed prosthesis for the next nine months and plan for implanted teeth placement, including multi-rooted mandibular molars denticles. Both groups received atraumatic extraction; then, the socket was preserved with bone allograft alone in the control group and bone allograft mixed with I-PRF, forming sticky bone, in the experimental group. Clinical, radiological, and histological assessments were taken at the inception stage, three months, six months, and nine months. A multivariate regression model and a generalized estimating equation (GEE) model were used to analyse the effects of these changes on outcomes. Results In all the parameters, the test group indicated a good amount of bone growth with increasing intervals of time for bone height radiographically with statistically significant difference present (p<0.05) and histologically after nine months when socket site grafted with bone graft in combination with I-PRF. Conclusion This study's results demonstrated that I-PRF possesses the potential to regenerate and heal in the tooth-extracted socket. This study further recommends the implementation of I-PRF in safeguarding and conserving the raised rim of the tooth. Future research should take place on the osteogenic capability of I-PRF in more comprehensive ridge accession surgical procedures and additional expanding and improving capacities in periodontal reconstruction.

Consequence of Synthetic Bone Substitute Used for Alveolar Cleft Graft Reconstruction (Preliminary Clinical Study)

Background  The outcome of alveolar grafting with synthetic bone substitute (Osteon III) in various bone defect volumes is highlighted. Methods  A prospective study was accomplished on 55 patients (6-13 years of age) with unilateral alveolar bone cleft. Osteon III, consisting of hydroxyapatite and tricalcium phosphate, is used to reconstruct the defect. Alveolus defect diameter was calculated before surgery (V1), after 3 months (V2), and finally after 6 months (V3) postsurgery. In the t -test, a significant difference and correlation between V1, V2, and V3 are stated. A p- value of 0.01 is considered a significant difference between parameters. Results  The degree of cleft is divided into three categories: small (9 cases), medium (20 patients), and large (26 cases).The bone volume of the clefted site is divided into three steps: volume 1: (mean 18.1091 mm 3 ); step 2: after 3 months, volume 2 resembles the amount of unhealed defect (mean 0.5109 mm 3 ); and the final bone volume assessment is made after 6 months (22.5455 mm 3 ). Both show statistically significant differences in bone volume formation. Conclusion  An alloplastic bone substitute can also be used as a graft material because of its unlimited bone retrieval. Osteon III can be used to reconstruct the alveolar cleft smoothly and effectively.

In Vitro and In Vivo Bone Regeneration Assessment of Titanium-Doped Waste Eggshell-Derived Hydroxyapatite in the Animal Model

In this work, a titanium-doped hydroxyapatite (HAp) scaffold was produced from two different sources (natural eggshell and laboratory-grade reagents) to compare the efficacy of natural and synthetic resources of HAp materials on new bone regeneration. This comparative study also reports the effect of Ti doping on the physical, mechanical, and in vitro as well as in vivo biological properties of the HAp scaffold. Pellets were prepared in the conventional powder metallurgy route, compacted, and sintered at 900 °C, showing sufficient porosity for bony ingrowth. The physical-mechanical characterizations were performed by density, porosity evaluation, XRD, FTIR, SEM analysis, and hardness measurement. In vitro interactions were evaluated by bactericidal assay, hemolysis, MTT assay, and interaction with simulated body fluid. All categories of pellets showed absolute nonhemolytic and nontoxic character. Furthermore, significant apatite formation was observed on the Ti-doped HAp samples in the simulated body fluid immersion study. The developed porous pellets were implanted to assess the bone defect healing in the femoral condyle of healthy rabbits. A 2 month study after implantation showed no marked inflammatory reaction for any samples. Radiological analysis, histological analysis, SEM analysis, and oxytetracycline labeling studies depicted better invasion of mature osseous tissue in the pores of doped eggshell-derived HAp scaffolds as compared to the undoped HAp, and laboratory-made samples. Quantification using oxytetracycline labeling depicted 59.31 ± 1.89% new bone formation for Ti-doped eggshell HAp as compared to Ti-doped pure HAp (54.41 ± 1.93) and other undoped samples. Histological studies showed the presence of abundant osteoblastic and osteoclastic cells in Ti-doped eggshell HAp in contrast to other samples. Radiological and SEM data also showed similar results. The results indicated that Ti-doped biosourced HAp samples have good biocompatibility, new bone-forming ability, and could be used as a bone grafting material in orthopedic surgery.

Alveolar ridge preservation in post-extraction sockets using concentrated growth factors: a split-mouth, randomized, controlled clinical trial

Aim

The aim of this clinical trial was to assess the impact of autologous concentrated growth factor (CGF) as a socket-filling material and its ridge preservation properties following the lower third molar extraction.

Materials and methods

A total of 60 sides of 30 participants who had completely symmetrical bilateral impacted lower third molars were enrolled. The primary outcome variables of the study were bone height and width, bone density, and socket surface area in the coronal section. Cone beam computed tomography images were obtained immediately after surgery and three months after surgery as a temporal measure. Follow-up data were compared to the baseline using paired and unpaired t-tests.

Results

CGF sites had higher values in height and width when compared to control sites (Buccal wall 32.9 ± 3.5 vs 29.4 ± 4.3 mm, Lingual wall 25.4 ± 3.5 vs 23.1 ± 4 mm, and Alveolar bone width 21.07 ± 1.55vs19.53 ± 1.90 mm, respectively). Bone density showed significantly higher values in CGF sites than in control sites (Coronal half 200 ± 127.3 vs -84.1 ± 121.3 and Apical half 406.5 ± 103 vs 64.2 ± 158.6, respectively). There was a significant difference between both sites in the reduction of the periodontal pockets.

Conclusion

CGF application following surgical extraction provides an easy, low-cost, and efficient option for alveolar ridge preservation. Thus, the use of CGF by dentists during dental extractions may be encouraged, particularly when alveolar ridge preservation is required.

Clinical trial registration

TCTR identification, TCTR20221028003.

Can a low dosage of recombinant human bone morphogenetic protein-2 loaded on collagen sponge induce ectopic bone?

Recombinant human bone morphogenetic protein-2 (rhBMP-2) is one of the growth factors that may induce the formation of new bone. The aim was to determine the efficacy of low doses of rhBMP-2 for bone regeneration using a collagen sponge as a carrier. Three doses of rhBMP-2 (1.167, 0.117, and 0.039 mg/mL) were combined with an absorbable collagen sponge (ACS) as a delivery vehicle. The rhBMP-2/ACS implants were placed in the subcutaneous tissues of rat backs. X-ray microcomputed tomography (micro-CT) and histological analysis were used to evaluate bone formation. The samples treated with 1.167 mg/mL of rhBMP-2 showed greater bone formation than the samples treated with 0.117 mg/mL of rhBMP-2 four weeks after surgery. However, there was no evidence of bone formation in the samples that were treated with 0.039 mg/mL of rhBMP-2. It was found that rhBMP-2 was osteogenic even at one-tenth of its manufacturer's recommended concentration (1.167 mg/mL), indicating its potential for clinical use at lower concentrations.

One-Step Preparation of an Injectable Hydrogel Scaffold System Capable of Sequential Dual-Growth Factor Release to Maximize Bone Regeneration

Numerous growth factors are involved in the natural bone healing process, which is precisely controlled in a time- and concentration-dependent manner. Mimicking the secretion pattern of growth factors could be an effective means to maximize the bone regeneration effect. However, achieving the sequential delivery of various growth factors without the use of multiple materials or complex scaffold designs is challenging. Herein, an injectable poly(organophosphazene) hydrogel scaffold (IPS) encapsulating bone morphogenetic protein (BMP)-2 and TGFβ-1 (IPS_BT) is studied to mimic the sequential secretion of growth factors involved in natural bone healing. The IPS_BT system is designed to release TGFβ-1 slowly while retaining BMP-2 for a longer period of time. When IPS_BT is injected in vivo, the hydrogel is replaced by bone tissue. In addition, angiogenic (CD31 and alpha-smooth muscle actin (α-SMA)) and stemness (Nanog and SOX2) markers are highly upregulated in the early stages of bone regeneration. The IPS system developed here has promising applications in tissue engineering because 1) various amounts of the growth factors can be loaded in one step, 2) the release pattern of each growth factor can be controlled via differences in their molecular interactions, and 3) the injected IPS can be degraded and replaced with regenerated bone tissue.

Recent advances on injectable nanocomposite hydrogels towards bone tissue rehabilitation

There has been significant interest in the recent past to develop injectable hydrogel scaffolds that follow minimally invasive implantation procedures towards efficient healing and regeneration of defective bone tissues. Such scaffolds offer several advantages, as they can be injected into the irregularly shaped defect and can act as a low‐density aqueous reservoir, incorporating necessary components for bone tissue repair and augmentation. Considering that bone is a biocomposite of natural biopolymer and bioapatite nanofiller, there has been a growing trend to develop nanocomposite scaffolds by combining biopolymers and inorganic nanofillers to biomimic the hierarchical nanostructure and composition of natural bone. Furthermore, the nanocomposite scaffolds can be tailored to have patient‐specific bone properties, which can lead to better biological responses. The present article begins with the introduction, followed by an overview of polymer matrices, property requirements, and crosslinking techniques employed for injectable hydrogels. Various strategies to develop injectable composites, with emphasis on nanocomposite hydrogels incorporating bioinert and bioactive nanofillers have been discussed. The fundamental challenges related to the development of injectable hydrogel nanocomposite scaffolds and the research efforts directed towards solving these problems have also been reviewed. Finally, future trends and conclusions on new generation injectable hydrogel nanocomposite bone scaffolds have been discussed in this article.

Efficacy of calcium sulfate dihydrate as a bone graft substitute in odontogenic cystic defects of jaws following enucleation: A clinical study

Background

The treatment of osseous bone defects created following enucleation of a cyst is an arduous challenge. Autogenous bone grafts despite being the gold standard have various drawbacks such as donor site morbidity, limited availability of bone graft, and increased operative time. Hence, there are various bone grafts which are being investigated which could overcome the limitations of autografts. Thus, this study was conducted to evaluate the efficacy of calcium sulfate (CS), a bone graft substitute, for spontaneous bone regeneration of cystic defects.

Objectives

The purpose of this study is to evaluate bone formation in odontogenic cystic defects following enucleation and reconstruction with bone graft substitute by three-dimensional radiographic and clinical evaluation.

Methodology

A total of twenty patients diagnosed with odontogenic cysts were randomly divided into two groups, out of which the study group had undergone enucleation with bone grafting (tobramycin-impregnated CS dihydrate) and the control group had undergone enucleation without bone grafting. The patients were evaluated clinically and radiographically at the 1st, 3rd, 6th, and 12th months postoperatively.

Results

There was no bone formation observed at 1 month postoperative in both the groups. There was a statistically significant higher bone defect reduction observed radiologically on orthopantomogram and computed tomography scan in the study group than the control group at the 3rd, 6th, and 12th months postoperative. The rate of reduction in cystic volume of the study group at the 12th month was 94.4% and in the control group was 37.16%.

Conclusion

Immediate grafting of cystic cavity can avoid complications such as pathological fracture due to less bone support, delayed healing, etc., The utilization of a graft with a property of inducing rapid bone formation should be taken into consideration. The use of CS as a grafting material accelerated the rate of bone regeneration in the cystic defects, with minimal complications.

Enhanced bone tissue regeneration with hydrogel-based scaffolds by embedding parathyroid hormone in mesoporous bioactive glass

OBJECTIVES

To evaluate hydrogel-based scaffolds embedded with parathyroid hormone (PTH)-loaded mesoporous bioactive glass (MBG) on the enhancement of bone tissue regeneration in vitro.

MATERIALS AND METHODS

MBG was produced via sol-gel technique followed by PTH solution imbibition. PTH-loaded MBG was blended into the hydrogels and submitted to a lyophilisation process associated with a chemical crosslinking reaction to the production of the scaffolds. Characterisation of the MBG and PTH-loaded MBG scaffolds, including the scanning electron microscope (SEM) connected with an X-ray detector (EDX), Fourier transform infrared (FTIR), compression strength, rheological measurements, swelling and degradation rates, and PTH release analysis, were performed. Also, bioactivity using simulated-body fluid (SBF), biocompatibility (MTT), and osteogenic differentiation analyses (von Kossa and Alizarin Red stainings, and μ-computed tomography, μCT) of the scaffolds were carried out.

RESULTS

SEM images demonstrated MBG particles dispersed into the hydrogel-based scaffold structure, which was homogeneously porous and well interconnected. EDX and FTIR revealed large amounts of carbon, oxygen, sodium, and silica in the scaffold composition. Bioactivity experiments revealed changes on sample surfaces over the analysed period, indicating the formation of carbonated hydroxyapatite; however, the chemical composition remained stable. PTH-loaded hydrogel-based scaffolds were biocompatible for stem cells from human-exfoliated deciduous teeth (SHED). A high quantity of calcium deposits on the extracellular matrix of SHED was found for PTH-loaded hydrogel-based scaffolds. μCT images showed MBG particles dispersed into the scaffolds' structure, and a porous, lamellar, and interconnected hydrogel architecture.

CONCLUSIONS

PTH-loaded hydrogel-based scaffolds demonstrated consistent morphology and physicochemical properties for bone tissue regeneration, as well as bioactivity, biocompatibility, and osteoinductivity in vitro. Thus, the scaffolds presented here are recommended for future studies on 3D printing.

CLINICAL RELEVANCE

Bone tissue regeneration is still a challenge for several approaches to oral and maxillofacial surgeries, though tissue engineering applying SHED, scaffolds, and osteoinductive mediators might help to overcome this clinical issue.

Biominerals Added Bioresorbable Calcium Phosphate Loaded Biopolymer Composites

Nanocrystalline calcium phosphate (CP) bioceramic coatings and their combination with biopolymers are innovative types of resorbable coatings for load-bearing implants that can promote the integration of metallic implants into human bodies. The nanocrystalline, amorphous CP particles are an advantageous form of the various calcium phosphate phases since they have a faster dissolution rate than that of crystalline hydroxyapatite. Owing to the biomineral additions (Mg, Zn, Sr) in optimized concentrations, the base CP particles became more similar to the mineral phase in human bones (dCP). The effect of biomineral addition into the CaP phases was thoroughly studied. The results showed that the shape, morphology, and amorphous characteristic slightly changed in the case of biomineral addition in low concentrations. The optimized dCP particles were then incorporated into a chosen polycaprolactone (PCL) biopolymer matrix. Very thin, non-continuous, rough layers were formed on the surface of implant substrates via the spin coating method. The SEM elemental mapping proved the perfect incorporation and distribution of dCP particles into the polymer matrix. The bioresorption rate of thin films was followed by corrosion measurements over a long period of time. The corrosion results indicated a faster dissolution rate for the dCP-PCL composite compared to the dCP and CP powder layers.

Bone Formation on Murine Cranial Bone by Injectable Cross-Linked Hyaluronic Acid Containing Nano-Hydroxyapatite and Bone Morphogenetic Protein

New injection-type bone-forming materials are desired in dental implantology. In this study, we added nano-hydroxyapatite (nHAp) and bone morphogenetic protein (BMP) to cross-linkable thiol-modified hyaluronic acid (tHyA) and evaluated its usefulness as an osteoinductive injectable material using an animal model. The sol (ux-tHyA) was changed to a gel (x-tHyA) by mixing with a cross-linker. We prepared two sol−gel (SG) material series, that is, x-tHyA + BMP with and without nHAp (SG I) and x-tHyA + nHAp with and without BMP (SG II). SG I materials in the sol stage were injected into the cranial subcutaneous connective tissues of mice, followed by in vivo gelation, while SG II materials gelled in Teflon rings were surgically placed directly on the cranial bones of rats. The animals were sacrificed 8 weeks after implantation, followed by X-ray analysis and histological examination. The results revealed that bone formation occurred at a high rate (>70%), mainly as ectopic bone in the SG I tests in mouse cranial connective tissues, and largely as bone augmentation in rat cranial bones in the SG II experiments when x-tHyA contained both nHAp and BMP. The prepared x-tHyA + nHAp + BMP SG material can be used as an injection-type osteoinductive bone-forming material. Sub-periosteum injection was expected.

Use of a Lateral Sinus Bony Window as an Intraoral Donor Site for Guided Bone Regeneration in Wide Post-Extraction Defects

Maxillary sinus augmentation (MSA) and guided bone regeneration (GBR) have shown successful clinical, radiological, and histological outcomes for implant-related bone reconstruction and have been used to augment bony defects of various shapes and sizes. This study demonstrated that the lateral sinus bony window obtained during MSA can be used as an autogenous block bone graft for the augmentation of wide post-extraction defects. During the uncovering procedure performed 6 months after surgery, the grafted lateral bony window was well integrated with the adjacent native bone, and complete bone filling was observed in all bony defects around the implants. All of the implants survived. Within the limitations of this study, autogenous block bone obtained from lateral window sites can be used as novel donors for the resolution of wide bony defects around implants.

Reconstruction of Natural Smile and Splinting with Natural Tooth Pontic Fiber-Reinforced Composite Bridge

Teeth replacement is challenging in old patients with severe periodontal disease, limiting prosthetics treatment options. Here, we report a fiber-reinforced composite (FRC) resin bridge using natural tooth pontic in a patient with severe periodontitis. A 60-year-old lady complaining of teeth mobility was diagnosed with severe periodontitis, recession, bone loss, and crowding in the anterior maxillary teeth. Due to a hopeless periodontal prognosis, lateral incisors were extracted and sectioned using a cylindrical diamond bur. The pulp chamber was debrided and filled with self-adhesive flowable composite resin. After three weeks, the pontics were fixed in proximal contact areas, and the FRC bridge was fabricated directly using the resin fiber strip followed by occlusion adjustment, finishing, and polishing. Esthetic, occlusion, and periodontal status were re-evaluated after six months. Here, FRC using natural pontic could successfully reconstruct a natural smile, splint the adjacent teeth, eliminate crowding, and provide stable occlusion. Therefore, this method may be considered for similar cases.

Performance of Biocomposite Materials Reinforced by Hydroxyapatite and Seashell Nanoparticles for Bone Replacement

Bone defects and disorders include trauma, osteonecrosis, osteoporosis, bone tumours, arthritis rheumatoid, osteosarcoma, and iatrogenic injury. Obtaining a composite material with characteristics that mimic what bones in the human body have is a vital target for the purpose of replacing or repairing damaged bones. The key objective of this study was to develop a composite having mechanical and biological properties that resemble to a large extent native bone features. Highly biocompatible epoxy resin was reinforced by various weight fractions of seashell nanoparticles. The morphologies of the pristine bioepoxy, seashell-bioepoxy, and hydroxyapatite-bioepoxy composites were observed by scanning electron microscopy. Moreover, the mechanical properties were examined by the means of tension and Izod impact tests. Besides, the influence of seashell and hydroxyapatite nanoparticles on the bioepoxy chemical structure and thermal properties was also evaluated using Fourier transform infrared spectroscopy and differential scanning calorimetry technique, respectively. The tensile strength, modulus of elasticity, and impact strength of the seashell nanoparticle-reinforced bioepoxy were revealed to be higher than those of the unmodified bioepoxy and were significantly depended on the filler content. When the mass fraction of the reinforcement was 7 wt%, the improvement in the tensile strength, modulus of elasticity, and impact strength was around 46.7%, 37%, and 57%, respectively, compared to that of blank bioepoxy. In addition, these properties were higher for the composites loaded with seashell nanoparticles than those filled with commercially available hydroxyapatite nanoparticles. An enhancement in glass transition temperature for the bioepoxy after modification with both of these nanofillers was also achieved. All these features make these kinds of composites a promising option that could be used in the orthopaedic field. Furthermore, the use of seashell nanoparticles may reduce the cost of the resulted composite and alleviate the negative consequences of large quantity by-product waste seashells on the environment.

Bioactive Inorganic Materials for Dental Applications: A Narrative Review

Over time, much attention has been given to the use of bioceramics for biomedical applications; however, the recent trend has been gaining traction to apply these materials for dental restorations. The bioceramics (mainly bioactive) are exceptionally biocompatible and possess excellent bioactive and biological properties due to their similar chemical composition to human hard tissues. However, concern has been noticed related to their mechanical properties. All dental materials based on bioactive materials must be biocompatible, long-lasting, mechanically strong enough to bear the masticatory and functional load, wear-resistant, easily manipulated, and implanted. This review article presents the basic structure, properties, and dental applications of different bioactive materials i.e., amorphous calcium phosphate, hydroxyapatite, tri-calcium phosphate, mono-calcium phosphate, calcium silicate, and bioactive glass. The advantageous properties and limitations of these materials are also discussed. In the end, future directions and proposals are given to improve the physical and mechanical properties of bioactive materials-based dental materials.

Dicalcium Phosphate Dihydrate Mineral Loaded Freeze-Dried Scaffolds for Potential Synthetic Bone Applications

Dicalcium Phosphate Dihydrate (DCPD) mineral scaffolds alone do not possess the mechanical flexibility, ease of physicochemical properties' tuneability or suitable porosity required for regenerative bone scaffolds. Herein, we fabricated highly porous freeze-dried chitosan scaffolds embedded with different concentrations of Dicalcium Phosphate Dihydrate (DCPD) minerals, i.e., 0, 20, 30, 40 and 50 (wt)%. Increasing DCPD mineral concentration led to increased scaffold crystallinity, where the % crystallinity for CH, 20, 30, 40, and 50-DCPD scaffolds was determined to be 0.1, 20.6, 29.4, 38.8 and 69.9%, respectively. Reduction in scaffold pore size distributions was observed with increasing DCPD concentrations of 0 to 40 (wt)%; coalescence and close-ended pore formation were observed for 50-DCPD scaffolds. 50-DCPD scaffolds presented five times greater mechanical strength than the DCPD mineral-free scaffolds (CH). DCPD mineral enhanced cell proliferation for the 20, 30 and 40-DCPD scaffolds. 50-DCPD scaffolds presented reduced pore interconnectivity due to the coalescence of many pores in addition to the creation of closed-ended pores, which were found to hinder osteoblast cell proliferation.

Guided Bone Regeneration Prior to Implant Therapy in the Esthetic Zone: A Case Report

Background:

Implant placement on the anterior maxilla requires a comprehensive concern of adequate alveolar bone and gingival biotype. Insufficient support for hard and soft tissues becomes one of the main causes of implant complications. To avoid this problem, pre-surgical treatment with Guided Bone Regeneration (GBR) is suggested with respect to the alveolar ridge defect.

Objective:

In this study, we reported the predictability of a sandwich technique of GBR prior to implant placement.

Case Presentation:

Case: Thirty-four-year-old male was referred with a chief complaint of missing teeth on area #21 accompanied by labial bone dehiscence due to trauma. Bone thickness measurement displayed was approximately 3/4/5 mm (coronal/middle third/apical third of the alveolar ridge). This case was diagnosed as soft and hard tissue deformity on area #21 prior to implant. Case management: GBR and implant placement were performed in two stages of surgery. GBR was executed by using a combination of Biphasic Calcium Phosphate (BCP) (consisting of 40% Beta-Tri Calcium Phosphate (β-TCP) and 60% Hydroxyapatite (HA)) and Demineralized Freeze-Dried Bone Allografts (DFDBA) bone graft materials. Alveolar ridge re-measurement five months after GBR showed significant bone augmentation, 6/6/6 mm (coronal/middle third/apical third of the alveolar ridge). Furthermore, a 3.5 mm (diameter) x 10 mm (length) bone-level implant was inserted accordingly. The two-year follow-up exhibited gingival stability and no sign of either recession or bone resorption.

Conclusion:

Herein, we demonstrated the effectiveness of BCP and DFDBA bone substitutes to obtain proper conditions for the long-termed stability and predictability of implant.

Biocompatibility Assessment of Two Commercial Bone Xenografts by In Vitro and In Vivo Methods

Bone substitutes based on xenografts have been used for a long time in bone regeneration thanks to their inductive capacity for bone tissue regeneration. Some bone-based scaffolds have been modified by adding collagen and other proteins to improve their regenerative capacity and prevent migration and aggregation, especially particles. However, rejection of this graft has been reported due to protein residues caused by poor material preparation. We compared the in vitro and in vivo biological response of two commercial xenografts (InterOss^®, F1 and InterOss^® Collagen, F2) and a commercial porcine collagen membrane (InterCollagen^® Guide, F3) as a rapid degradation control. Fourier Transform Infrared Spectroscopy (FT-IR) analysis evidenced the presence of hydroxyl, orthophosphate, and carbonate groups of the xenografts and amide groups of collagen. Thermogravimetric analysis (TGA) of the xenografts demonstrated their thermal stability and the presence of a few amounts of organic material. The study by differential scanning calorimetry showed the presence of endothermic peaks typical of the dehydration of the xenografts (F1 and F2) and for the collagen membrane (F3), the beginning of structural three-dimensional protein changes. Subsequently, in vitro biocompatibility tests were carried out for the materials with Artemia salina and MTT cell viability with HeLa cells, demonstrating the high biocompatibility of the materials. Finally, in vivo biocompatibility was studied by implanting xenografts in biomodels (Wistar rats) at different periods (30, 60, and 90 days). The F1 xenograft (InterOss) remained remarkably stable throughout the experiment (90 days). F2 (InterOss Collagen) presented a separation of its apatite and collagen components at 60 days and advanced resorption at 90 days of implantation. Finally, the collagen membrane (F3) presented faster resorption since, at 90 days, only some tiny fragments of the material were evident. All the in vivo and in vitro test results demonstrated the biocompatibility of the xenografts, demonstrating the potential of these materials for tissue engineering.

Specially designed and CAD/CAM manufactured allogeneic bone blocks using for augmentation of a highly atrophic maxilla show a stable base for an all-on-six treatment concept: a case report

Background

In terms of a highly atrophic maxilla, bone augmentation still remains very challenging. With the introduction of computer-aided design/computer-aided manufacturing (CAD/CAM) for allogeneic bone blocks, a new method for the treatment of bone deficiencies was created. This case report demonstrates the successful use of two specially designed and CAD/CAM manufactured allogeneic bone blocks for a full arch reconstruction of a highly atrophic maxilla with an all-on-six concept.

Case presentation

We report the case of a 55-year-old male patient with a highly atrophic maxilla and severe bone volume deficiencies in horizontal and vertical lines. In order to treat the defects, the surgeon decided to use a combination of two allogeneic bone blocks and two sinus floor augmentations. The bone blocks were fabricated from the data of a cone beam computed tomography (CBCT) using CAD/CAM technology. After the insertion of the two bone blocks and a healing period of 7 months, six dental implants were placed in terms of an all-on-six concept. The loading of the implants took place after an additional healing time of 7 months with a screw-retained prosthetic construction and with a milled titanium framework with acrylic veneers.

Conclusion

The presented procedure shows the importance of the precise design of CAD/CAM manufactured allogeneic bone blocks for the successful treatment of a highly atrophic maxilla. Proper soft-tissue management is one of the key factors to apply this method successfully.

Reshapable Osteogenic Biomaterials Combining Flexible Melt Electrowritten Organic Fibers with Inorganic Bioceramics

Ever-growing various applications, especially for tissue regeneration, cause a pressing need for novel methods to functionalize melt electrowritten (MEW) microfibrous scaffolds with unique nanomaterials. Here, two novel strategies are proposed to modify MEW polycaprolactone (PCL) grids with ZnO nanoparticles (ZP) or ZnO nanoflakes (ZF) to enhance osteogenic differentiation. The calcium mineralization levels of MC3T3 osteoblasts cultured on PCL/ZP 0.1 scaffolds are ∼3.91-fold higher than those cultured on nonmodified PCL scaffolds, respectively. Due to the nanotopography mimicking bone anatomy, the PCL/ZF scaffolds (∼2.60 times higher in ALP activity compared to PCL/ZP 1 and ∼2.17 times higher in mineralization compared to PCL/ZP 0.1) achieved superior results. Moreover, the flexible feature inherited from PCL grids makes it possible for them to act as a reshapable osteogenic bioscaffold. This study provides new strategies for synthesizing nanomaterials on microscale surfaces, opening up a new route for functionalizing MEW scaffolds to fulfill the growing demand of tissue engineering.

Biomedical Membrane of Fish Collagen/Gellan Gum Containing Bone Graft Materials

The development of a guided bone regeneration (GBR) membrane with non-mammalian fish collagen has the advantage of low risk for transmission of infectious diseases in tissue regeneration. In this work, a fish collagen/gellan gum and bone graft material (FC/GG-BGM) composite GBR membrane were fabricated through solution blending and casting procedures in a vacuum. The membranes were characterized using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy observation (SEM), and atomic force microscope (AFM) analyses. FT-IR results suggested that ionic interactions were formed between FC and GG both in composite powder and membranes. In vivo experiments showed that these FC/GG-BGM composite membranes could generate osteoblast minerals and promote loose bone calcification, thus accelerating bone regeneration. At 2 weeks, the defected site of rats treated with FC/GG-BGM membrane (0.377 ± 0.012 mm3) showed higher regeneration than that of rats treated with the bovine collagen membrane (0.290 ± 0.015 mm3) and control rats without membrane (0.160 ± 0.008 mm3). Compared with bovine collagen membrane, the FC/GG-BGM composite membrane displays better bone regeneration ability. Therefore, FC/GG-BGM composite membrane is suitable as a GBR membrane for bone regeneration.

Comparison of the Morphological and Structural Characteristic of Bioresorbable and Biocompatible Hydroxyapatite-Loaded Biopolymer Composites

Calcium phosphate (CaP)-based ceramic-biopolymer composites can be regarded as innovative bioresorbable coatings for load-bearing implants that can promote the osseointegration process. The carbonated hydroxyapatite (cHAp) phase is the most suitable CaP form, since it has the highest similarity to the mineral phase in human bones. In this paper, we investigated the effect of wet chemical preparation parameters on the formation of different CaP phases and compared their morphological and structural characteristics. The results revealed that the shape and crystallinity of CaP particles were strongly dependent on the post-treatment methods, such as heat or alkaline treatment of as-precipitated powders. In the next step, the optimised cHAp particles have been embedded into two types of biopolymers, such as polyvinyl pyrrolidone (PVP) and cellulose acetate (CA). The pure polymer fibres and the cHAp-biopolymer composites were produced using a novel electrospinning technique. The SEM images showed the differences between the morphology and network of CA and PVP fibres as well as proved the successful attachment of cHAp particles. In both cases, the fibres were partially covered with cHAp clusters. The SEM measurements on samples after one week of immersion in PBS solution evidenced the biodegradability of the cHAp-biopolymer composites.

A Review of the Effects of Collagen Treatment in Clinical Studies

Collagen, an abundant extracellular matrix protein, has been found to have a lot of pharmaceuticals, medicine, food, and cosmetics applications. Increased knowledge of collagen sources, extraction techniques, structure, and properties in the last decades has helped develop more collagen-based products and tissue engineering biomaterials. Collagen products have been playing an important role in benefiting the health of the human body, especially for aging people. In this paper, the effects of collagen treatment in different clinical studies including skin regeneration, bone defects, sarcopenia, wound healing, dental therapy, gastroesophageal reflux, osteoarthritis, and rheumatoid arthritis have been reviewed. The collagen treatments were significant in these clinical studies. In addition, the associations between these diseases were discussed. The comorbidity of these diseases might be closely related to collagen deficiency, and collagen treatment might be a good choice when a patient has more than one of these diseases, including the coronavirus disease 2019 (COVID-19). It concludes that collagen-based medication is useful in treating comorbid diseases and preventing complications.

Possible Treatment of Severe Bone Dehiscences Based on 3D Bone Reconstruction—A Description of Treatment Methodology

Gingival recessions constitute serious limitations for effective interdisciplinary periodontal, orthodontic, and implant therapy. A proper bone morphology of the alveolar bone and soft tissues that cover it are interdependent. The regeneration procedures known to date are based on the use of autogenous bone, or its allogeneic, xenogeneic, or alloplastic substitutes. These substitutes are characterized by different osteogenesis potentials. No effective procedure for three-dimensional bone reconstruction for cases in which there is dentition with recessions has been described to date, especially in its vertical dimension. This article presents the patented method of the three-dimensional bone reconstruction of the anterior mandible with preserved dentition when using an allogeneic bone block, and also includes a case report with a 2-year follow-up as an example. Based on clinical observations, it was stated that the intended therapeutic effect was achieved. There was no recession, shallowing of the vestibule, signs of inflammation, or pathological mobility of the teeth in the area undergoing reconstruction. The radiographic images revealed the formation of a new layer of cortical bone on the vestibular side and a certain volume of cancellous bone. No radiological demarcation zone of brightening, which indicates an incomplete adaptation, integration, and reconstruction of the bone block, was found.

Enhanced osteoinductive capacity of poly(lactic-co-glycolic) acid and biphasic ceramic scaffolds by embedding simvastatin

OBJECTIVES

This study evaluated the effect of embedding simvastatin (SIM) on the osteoinductive capacity of PLGA + HA/βTCP scaffolds in stem cells from human exfoliated deciduous teeth (SHED).

MATERIALS AND METHODS

Scaffolds were produced by PLGA solvent dissolution, addition of HA/βTCP, solvent evaporation, and leaching of sucrose particles to impart porosity. Biphasic ceramic particles (70% HA/30% βTCP) were added to the PLGA in a 1:1 (w:w) ratio. Scaffolds with SIM received 1% (w:w) of this medication. Scaffolds were synthesized in a disc-shape and sterilized by ethylene oxide. The experimental groups were (G1) PLGA + HA/βTCP and (G2) PLGA + HA/βTCP + SIM in non-osteogenic culture medium, while (G3) SHED and (G4) MC3T3-E1 in osteogenic culture medium were the positive control groups. The release profile of SIM from scaffolds was evaluated. DNA quantification assay, alkaline phosphatase activity, osteocalcin and osteonectin proteins, extracellular calcium detection, von Kossa staining, and X-ray microtomography were performed to assess the capacity of scaffolds to induce the osteogenic differentiation of SHED.

RESULTS

The release profile of SIM followed a non-liner sustained-release rate, reaching about 40% of drug release at day 28. Additionally, G2 promoted the highest osteogenic differentiation of SHED, even when compared to the positive control groups.

CONCLUSIONS

In summary, the osteoinductive capacity of poly(lactic-co-glycolic) acid and biphasic ceramic scaffolds was expressively enhanced by embedding simvastatin.

CLINICAL RELEVANCE

Bone regeneration is still a limiting factor in the success of several approaches to oral and maxillofacial surgeries, though tissue engineering using mesenchymal stem cells, scaffolds, and osteoinductive mediators might collaborate to this topic.

Animal models of vertical bone augmentation (Review)

Vertical bone augmentation is an important challenge in dental implantology. Existing vertical bone augmentation techniques, along with bone grafting materials, have achieved certain clinical progress but continue to have numerous limitations. In order to evaluate the possibility of using biomaterials to develop bone substitutes, medical devices and/or new bone grafting techniques for vertical bone augmentation, it is essential to establish clinically relevant animal models to investigate their biocompatibility, mechanical properties, applicability and safety. The present review discusses recent animal experiments related to vertical bone augmentation. In addition, surgical protocols for establishing relevant preclinical models with various animal species were reviewed. The present study aims to provide guidance for selecting experimental animal models of vertical bone augmentation.

Vertical mandibular bone augmentation by the osteodistraction of the transplanted fibula free flap: A case series with long-term follow-up

Vertical augmentation of the mandible to prepare dental implant therapy is still a challenge, especially with large mandible defects. Reconstruction with fibula free flap is a regularly applied approach in such cases, but it does not always yield optimal results: the resulting crestal height might differ significantly from the crestal height of the patient's intact bone, which makes esthetic and functional rehabilitation difficult. Osteodistraction of the integrated flap is a known but rarely discussed approach where the already integrated flap undergoes additional distraction. Through the four cases reported here, we would like to demonstrate that the osteodistraction of the transplanted fibula free flap is a useful and efficient method of secondary augmentation for cases where the flap itself fails to produce the desired crestal height, and no other method is applicable. The cases show that the method allows outcomes that are highly satisfactory, both in the functional and esthetic sense.

Zn-Containing Membranes for Guided Bone Regeneration in Dentistry

Barrier membranes are employed in guided bone regeneration (GBR) to facilitate bone in-growth. A bioactive and biomimetic Zn-doped membrane with the ability to participate in bone healing and regeneration is necessary. The aim of the present study is to state the effect of doping the membranes for GBR with zinc compounds in the improvement of bone regeneration. A literature search was conducted using electronic databases, such as PubMed, MEDLINE, DIMDI, Embase, Scopus and Web of Science. A narrative exploratory review was undertaken, focusing on the antibacterial effects, physicochemical and biological properties of Zn-loaded membranes. Bioactivity, bone formation and cytotoxicity were analyzed. Microstructure and mechanical properties of these membranes were also determined. Zn-doped membranes have inhibited in vivo and in vitro bacterial colonization. Zn-alloy and Zn-doped membranes attained good biocompatibility and were found to be non-toxic to cells. The Zn-doped matrices showed feasible mechanical properties, such as flexibility, strength, complex modulus and tan delta. Zn incorporation in polymeric membranes provided the highest regenerative efficiency for bone healing in experimental animals, potentiating osteogenesis, angiogenesis, biological activity and a balanced remodeling. Zn-loaded membranes doped with SiO₂ nanoparticles have performed as bioactive modulators provoking an M2 macrophage increase and are a potential biomaterial for promoting bone repair. Zn-doped membranes have promoted pro-healing phenotypes.

PLGA+HA/βTCP Scaffold Incorporating Simvastatin: A Promising Biomaterial for Bone Tissue Engineering

The aim of this study was to synthesize, characterize, and evaluate degradation and biocompatibility of poly(lactic-co-glycolic acid) + hydroxyapatite/β-tricalcium phosphate (PLGA+HA/βTCP) scaffolds incorporating simvastatin (SIM) to verify if this biomaterial might be promising for bone tissue engineering. Samples were obtained by the solvent evaporation technique. Biphasic ceramic particles (70% HA, 30% βTCP) were added to PLGA in a ratio of 1:1. Samples with SIM received 1% (m/m) of this medication. Scaffolds were synthesized in a cylindric shape and sterilized by ethylene oxide. For degradation analysis, samples were immersed in phosphate-buffered saline at 37°C under constant stirring for 7, 14, 21, and 28 days. Nondegraded samples were taken as reference. Mass variation, scanning electron microscopy, porosity analysis, Fourier transform infrared spectroscopy, differential scanning calorimetry, and thermogravimetry were performed to evaluate physico-chemical properties. Wettability and cytotoxicity tests were conducted to evaluate the biocompatibility. Microscopic images revealed the presence of macro-, meso-, and micropores in the polymer structure with HA/βTCP particles homogeneously dispersed. Chemical and thermal analyses presented similar results for both PLGA+HA/βTCP and PLGA+HA/βTCP+SIM. The incorporation of simvastatin improved the hydrophilicity of scaffolds. Additionally, PLGA+HA/βTCP and PLGA+HA/βTCP+SIM scaffolds were biocompatible for osteoblasts and mesenchymal stem cells. In summary, PLGA+HA/βTCP scaffolds incorporating simvastatin presented adequate structural, chemical, thermal, and biological properties for bone tissue engineering.

Collagen-based biomaterials for biomedical applications

Collagen is an insoluble fibrous protein that composes the extracellular matrix in animals. Although collagen has been used as a biomaterial since 1881, the properties and the complex structure of collagen are still extensive study subjects worldwide. In this article, several topics of importance for understanding collagen research are reviewed starting from its historical milestones, followed by the description of the collagen superfamily and its complex structures, with a focus on type I collagen. Subsequently, some of the superior properties of collagen-based biomaterials, such as biocompatibility, biodegradability, mechanical properties, and cell activities, are pinpointed. These properties make collagen applicable in biomedicine, such as wound healing, tissue engineering, surface coating of medical devices, and skin supplementation. Moreover, some antimicrobial strategies and the general host tissue responses regarding collagen as a biomaterial are presented. Finally, the current status and clinical application of the three-dimensional (3D) printing techniques for the fabrication of collagen-based scaffolds and the reconstruction of the human heart's constituents, such as capillary structures or even the entire organ, are discussed. Besides, an overall outlook for the future of this unique biomaterial is provided.

Three-dimensional bioactive hydrogel-based scaffolds for bone regeneration in implant dentistry

Bone tissue requires a range of complex mechanisms to allow the restoration of its structure and function. Bone healing is a signaling cascade process, involving cells secreting cytokines, growth factors, and pro-inflammatory factors in the defect site that will, subsequently, recruit surrounding stem cells to migrate, proliferate, and differentiate into bone-forming cells. Bioactive functional scaffolds could be applied to improve the bone healing processes where the organism is not able to fully regenerate the lost tissue. However, to be optimal, such scaffolds should act as osteoconductors - supporting bone-forming cells, providing nutrients, and sustaining the arrival of new blood vessels, and act as osteoinducers - slowly releasing signaling molecules that stimulate mesenchymal stem cells to differentiate and deposit mineralized bone matrix. Different compositions and shapes of scaffolds, cutting-edge technologies, application of signaling molecules to promote cell differentiation, and high-quality biomaterials are reaching favorable outcomes towards osteoblastic differentiation of stem cells in in vitro and in vivo researches for bone regeneration. Hydrogel-based biomaterials are being pointed as promising for bone tissue regeneration; however, despite all the research and high-impact scientific publications, there are still several challenges that prevent the use of hydrogel-based scaffolds for bone regeneration being feasible for their clinical application. Hence, the objective of this review is to consolidate and report, based on the current scientific literature, the approaches for bone tissue regeneration using bioactive hydrogel-based scaffolds, cell-based therapies, and three-dimensional bioprinting to define the key challenges preventing their use in clinical applications.

Materials and Manufacturing Techniques for Polymeric and Ceramic Scaffolds Used in Implant Dentistry

Preventive and regenerative techniques have been suggested to minimize the aesthetic and functional effects caused by intraoral bone defects, enabling the installation of dental implants. Among them, porous three-dimensional structures (scaffolds) composed mainly of bioabsorbable ceramics, such as hydroxyapatite (HAp) and β-tricalcium phosphate (β-TCP) stand out for reducing the use of autogenous, homogeneous, and xenogenous bone grafts and their unwanted effects. In order to stimulate bone formation, biodegradable polymers such as cellulose, collagen, glycosaminoglycans, polylactic acid (PLA), polyvinyl alcohol (PVA), poly-ε-caprolactone (PCL), polyglycolic acid (PGA), polyhydroxylbutyrate (PHB), polypropylenofumarate (PPF), polylactic-co-glycolic acid (PLGA), and poly L-co-D, L lactic acid (PLDLA) have also been studied. More recently, hybrid scaffolds can combine the tunable macro/microporosity and osteoinductive properties of ceramic materials with the chemical/physical properties of biodegradable polymers. Various methods are suggested for the manufacture of scaffolds with adequate porosity, such as conventional and additive manufacturing techniques and, more recently, 3D and 4D printing. The purpose of this manuscript is to review features concerning biomaterials, scaffolds macro and microstructure, fabrication techniques, as well as the potential interaction of the scaffolds with the human body.

Analysis of Sagittal Position Changes of the Condyle After Mandibular Setback Surgery Across the Four Different Types of Plating Systems

The authors analyzed the three-dimensional postoperative condylar position change across the plating systems. This retrospective study was conducted with the patients who underwent bilateral sagittal split ramus osteotomy with setback surgery. The condylar change was analyzed from preoperative cone-beam computed tomography to postoperative 1 month (T1) and postoperative 6 months (T2) using superimposition software, automatically merging based on the anterior cranial base. The condylar changes during T1 and T2 were analyzed across the four types of plates (4-hole sliding, heart-shaped, 3-hole sliding, and 4-hole conventional) Mean intraclass correlation coefficient values were consistently high for each measurement (>0.850). During T1, the conventional plate had a decreased condylar anterior distance when compared with the 3-hole sliding plate (P = 0.032). During T2, the conventional plate had an increased condylar posterior distance when compared with the 3-hole sliding plate (P = 0.031). Superimposition software based on the anterior cranial base could be available for measurement of condylar position with highly reproducible results. After bilateral sagittal split ramus osteotomy, the 3-hole sliding plate could effectively compensate for the anterior displacement of the condyle compared to other plates.

Beta-tricalcium phosphate promotes osteogenic differentiation of bone marrow-derived mesenchymal stem cells through macrophages

Macrophages are vital regulators of skeletal remodeling and osseous repair. Beta-tricalcium phosphate (β-TCP) is a synthetic ceramic biomaterial that has shown promise as bone substitute. However, whether and how β-TCP affects osteogenesis-related responses of macrophages has rarely been studied. The aims of this study were to explore (a) the effects of β-TCP on osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs) co-cultured with macrophages and (b) on macrophage polarization as well as macrophage gene and protein expression profiles. BMSC osteogenic differentiation capacity in vitro was enhanced in β-TCP-induced co-cultured BMSCs compared to that in BMSC monocultures. We also found that macrophages induced with 25 mg ml^-1 β-TCP extract had more significant immune responses and switched to the M2 phenotype. Expression levels of the Wnt signaling pathway modulators wingless-type MMTV integration site family, member 6 (WNT6) and Wnt inhibitory factor 1 (WIF1) were upregulated and downregulated, respectively, in macrophages treated with β-TCP extract. Our findings suggest that β-TCP enhances osteogenic differentiation of BMSCs by inducing macrophage polarization and by regulating the Wnt signaling pathway, thereby highlighting its therapeutic potential for bone healing through osteoimmunomodulatory properties.

Ibandronate Reduces the Surface Bone Resorption of Mandibular Bone Grafts: A Randomized Trial With Internal Controls

Autologous bone grafts are considered the gold standard for reconstruction of the edentulous alveolar ridges. However, this procedure is associated with unpredictable bone loss caused by physiological bone resorption. Bisphosphonates are antiresorptive drugs that act specifically on osteoclasts, thereby maintaining bone density, volume, and strength. It was hypothesized that the resorption of bone grafts treated with an ibandronate solution would be less advanced than bone grafts treated with saline. Ten patients who underwent bilateral sagittal split osteotomy were included in a randomized double‐blind trial with internal controls. Each patient received a bone graft treated with a solution of ibandronate on one side and a graft treated with saline (controls) contralaterally. Radiographs for the measurement of bone volume were obtained at 2 weeks and at 6 months after surgery. The primary endpoint was the difference in the change of bone volume between the control and the ibandronate bone grafts 6 months after surgery. All of the bone grafts healed without complications. One patient was excluded because of reoperation. In eight of the nine patients, the ibandronate bone grafts showed an increase in bone volume compared with baseline, with an average gain of 126 mm³ (40% more than baseline) with a range of +27 to +218 mm³. Only one ibandronate‐treated graft had a decrease in bone volume (8%). In the controls, an average bone volume loss of −146 mm³ (58% of baseline) with a range of −29 to −301 mm³ was seen. In the maxillofacial field, the reconstructions of atrophic alveolar ridges, especially in the esthetical zones, are challenging. These results show that bone grafts locally treated with ibandronate solution increases the remaining bone volume. This might lead to new possibilities for the maxillofacial surgeons in the preservation of bone graft volumes and for dental implant installations. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC. on behalf of American Society for Bone and Mineral Research.

Early osteoimmunomodulatory effects of magnesium-calcium-zinc alloys

Today, substantial attention is given to biomaterial strategies for bone regeneration, and among them, there is a growing interest in using immunomodulatory biomaterials. The ability of a biomaterial to induce neo vascularization and macrophage polarization is a major factor in defining its success. Magnesium (Mg)-based degradable alloys have attracted significant attention for bone regeneration owing to their biodegradability and potential for avoiding secondary removal surgeries. However, there is insufficient evidence in the literature regarding the early inflammatory responses to these alloys in vivo. In this study, we investigated the early body responses to Mg-0.45wt%Zn-0.45wt%Ca pin-shaped alloy (known as ZX00 alloy) in rat femora 2, 5, and 10 days after implantation. We used 3D micro computed tomography (µCT), histological, immunohistochemical, histomorphometrical, and small angle X-ray scattering (SAXS) analyses to study new bone formation, early macrophage polarization, neo vascularization, and bone quality at the implant bone interface. The expression of macrophage type 2 biological markers increased significantly after 10 days of Mg alloy implantation, indicating its potential in stimulating macrophage polarization. Our biomineralization results using µCT as well as histological stained sections did not indicate any statistically significant differences between different time points for both groups. The activity of alkaline phosphatase (ALP) and Runt-related transcription factor 2 (Runx 2) biological markers decreased significantly for Mg group, indicating less osteoblast activity. Generally, our results supported the potential of ZX00 alloy to enhance the expression of macrophage polarization in vivo; however, we could not observe any statistically significant changes regarding biomineralization.

Synthetic Polymeric Materials for Bone Replacement

Some treatment options available to repair bone defects are the use of autogenous and allogeneic bone grafts. The drawback of the first one is the donor site’s limitation and the need for a second operation on the same patient. In the allograft method, the problems are associated with transmitted diseases and high susceptibility to rejection. As an alternative to biological grafts, polymers can be used in bone repair. Some polymers used in the orthopedic field are poly(methyl methacrylate), poly(ether-ether-ketone), and ultra-high molecular weight polyethylene (UHMWPE). UHMWPE has drawn much attention since it combines low friction coefficient and high wear and impact resistance. However, UHMWPE is a bioinert material, which means that it does not interact with the bone tissue. UHMWPE composites and nanocomposites with hydroxyapatite (HA) are widely studied in the literature to mitigate these issues. HA is the main component of the inorganic phase in the natural bone, and the addition of this bioactive filler to the polymeric matrix aims to mimic bone composition. This brief review discusses some polymers used in orthopedic applications, focusing on the UHMWPE/HA composites as a potential bone substitute.

Propolis extract and bovine bone graft combination in the expression of VEGF and FGF2 on the preservation of post extraction socket

Aim:

To determine the potential of propolis extract and BBG combination on the quantity of fibroblast growth factor 2 (FGF-2), vascular endothelial growth factor (VEGF), and osteoblasts in the preservation of tooth extraction socket on days 3 and 7.

Settings and Design:

Laboratory in vivo reseach using animal model.

Materials and Methods:

Fifty-six Cavia cobaya were divided into eight groups containing seven animals in each group. The extraction socket on the lower left incisor was filled with polyethylene glycol (PEG) at a concentration of 2% (Groups I and II) as a control; active materials consisted of propolis extract and PEG (Groups III and IV); active materials consisted of BBG and PEG (Groups V and VI); and active materials consisted of propolis extract, BBG, and PEG (Groups VII and VIII). Then, an examination was done using immunohistochemistry to perform an expression of VEGF, FGF2, as well as histology of osteoblasts.

Statistical Analysis Used:

The statistical analysis performed using a one-way ANOVA and Tukey's honestly significant difference test.

Results:

Propolis extract, BBG and PEG had the most significant result related to the formation of FGF2, VEGF, and osteoblasts.

Conclusion:

The combination of propolis extract with BBG and PEG in socket preservation is effective in increasing the expression of FGF2, VEGF, and osteoblasts.

A Modified Ridge Splitting Technique Using Autogenous Bone Blocks-A Case Series

Background: Alveolar atrophy following tooth loss is a common limitation of rehabilitation with dental implant born prostheses. Ridge splitting is a well-documented surgical method to restore the width of the alveolar ridge prior to implant placement. The aim of this case series is to present a novel approach to ridge expansion using only autogenous bone blocks. Methods: Patients with Kennedy Class I. and II. mandibles with insufficient bone width were included in this study. Ridge splitting was carried out with the use of a piezoelectric surgery device by preparing osteotomies and after mobilization of the buccal cortical by placing an autologous bone block harvested from the retromolar region as a spacer between the buccal and lingual cortical plates. Block-grafts were stabilized by osteosynthesis screws. Implant placement was carried out after a 3-month healing period. A total of 13 implants were placed in seven augmented sites of six patients. Results: Upon re-entry, all sites healed uneventfully. Mean ridge width gain was 2.86 mm, range: 2.0–5.0 mm. Conclusions: Clinical results of our study show that the modified ridge splitting technique is a safe and predictable method to restore width of the alveolar ridge prior to implant placement.