Alveolar bone defects caused by inflammation or trauma jeopardize patients' oral functions. Guided bone regeneration (GBR) is widely used in repairing periodontal tissue, with barrier membranes play a crucial role in preserving the bone regeneration space. In this study, an injectable dual-crosslinked hydrogel was developed to improve the existing barrier membranes in flexibility and functionality. The hydrogel matrix, composed of methacrylated carboxymethyl chitosan (CMCS) reinforced with robust silk fibroin (SF), was further functionalized with bioactive glass (BG) particles to promote bone regeneration. The pre-gel solution achieved a fast-curing process under visible light and at body temperature. Further, the composite hydrogels presented good biocompatibility, biodegradability, resilience, alongside in vitro barrier effect against human gingival fibroblasts (HGFs). It significantly enhanced osteogenic differentiation and angiogenesis of bone marrow mesenchymal stem cells (BMSCs), facilitate the tube formation of human umbilical vein endothelial cells (HUVECs), and inhibit Staphylococcus aureus and Porphyromonas gingivalis. In a rat skull defect model, the osteogenic performance of hydrogels was comparable with that of collagen membranes (Bio-Gide®). Overall, this in-situ gel-forming barrier material served as a stable carrier for bioactive ions and a biomineralized scaffold for tissue ingrowth, supporting the enhancement of GBR technique.

This study was performed to evaluate the regenerative capabilities of levan hydrogels when combined with conventional bone graft materials (Bio-Oss®) in guided bone regeneration (GBR). With the growing interest in the application of levan polysaccharide for regenerative purposes over the last decade, a noticeable gap in in-vivo validations remains. This research therefore fills this gap by utilizing the cytocompatibility and cell proliferation potential of levan hydrogels and marks a preliminary effort in its use in combination with Bio-Oss® for bone regeneration, which was examined both in-vitro and in-vivo for the first time. Considerable increases in cell viability (nearly 180 %) attributed to the addition of levan hydrogels alone and with Bio-Oss® (2:2) was detected. In parallel, a histological examination revealed a significant increase in new bone formation compared with the administration of Bio-Oss® alone. The results conclusively demonstrate for the first time that the combination of levan hydrogel with Bio-Oss® results in histopathologically superior new bone formation compared to Bio-Oss® used alone. Additionally, this combination promoted greater osteoblast density and neovascularization. These outcomes not only emphasize the potential of levan hydrogels in enhancing GBR but also suggest their broader applicability in bone regeneration strategies.

Guided tissue regeneration (GTR) and guided bone regeneration (GBR) are two common dental regenerative procedures used to repair periodontal defects caused by periodontitis. In both procedures, a barrier membrane is placed at the interface between the soft tissue and the periodontal defect, serving to impede the infiltration of soft tissue while creating a secluded space for periodontal regeneration. Recently, barrier membranes based on chitosan (CS) have emerged as a promising avenue for these applications. However, despite numerous studies on the development of CS-based membranes, comprehensive review articles specifically addressing their progress in GTR/GBR applications remain scarce. Herein, we review recent research and advancements in the use of CS-based membranes for periodontal GTR and GBR. The review begins by highlighting the advantageous properties of CS that make it a suitable biomaterial for GTR/GBR applications. Next, the development of composite CS-based membranes, reinforced with various compositions like bioactive fillers and therapeutic agents, is discussed in detail based on recent literature, with a focus on their enhanced efficacy in promoting periodontal regeneration. Finally, the review explores the emergence of functionally graded CS-based membranes, emphasizing their potential to address specific challenges encountered in GTR/GBR procedures.

This study assessed the efficacy of antimicrobial photodynamic therapy (aPDT) with toluidine blue (TB) for decontamination of resorbable membranes inoculated with Streptococcus mutans (S. mutans).

In this in vitro study, Mucoderm and Jason resorbable membranes were cut into 15 pieces each, and were inoculated with S. mutans at 105 colony forming units (CFUs)/mL concentration. The membranes were subsequently assigned to 3 subgroups each (n = 5), for decontamination with TB (100 µg/mL) activated by 635 nm laser (60 s) as the experimental group (aPDT), 0.12 % chlorhexidine (CHX) as the positive control, and phosphate buffered saline (PBS) as the negative control. Changes in colony count after the interventions were calculated. Data were analyzed by the Kruskal-Wallis and Dunn's tests (alpha=0.05).

In both membrane types, the difference in colony count was significant among the three subgroups (P = 0.002). The lowest colony count was noted in the CHX subgroup, and the highest was recorded in the PBS subgroup. aPDT caused a significant reduction in colony count compared with the negative control group (P = 0.002). Significant differences were found between all three groups in pairwise comparisons (P < 0.05). The efficacy of aPDT was not significantly different for decontamination of the two membrane types (P = 635).

aPDT with 635 nm diode laser and TB had optimal efficacy (although inferior to CHX) for decontamination of both Jason and Mucoderm resorbable membranes inoculated with S. mutans.

The effects of optical clearing of implantable collagen materials were studied using optical clearing agents (OCAs) based on aqueous glucose solutions of various concentrations. By measuring the kinetics of the collimated transmission spectra, the diffusion D and permeability P coefficients of the OCAs of collagen materials were determined as D = (0.22 ± 0.05) × 10-6 to (1.41 ± 0.05) × 10-6 cm2/c and P = (0.55 ± 0.04) × 10-4 to (1.77 ± 0.07) × 10-4 cm/c. Studies with optical coherence tomography (OCT) confirmed that each of the OCAs used had an effect on the optical properties of collagen materials, and allowed us to quantify the group refractive indices of the collagen of various samples, which turned out to be in the range from nc = 1.476 to nc = 1.579.

Bone graft absorption and infection are the major challenges to guided bone regeneration(GBR), yet the GBR membrane is neither osteogenic nor antibacterial. Hence, we followed sono-piezo therapy strategy by fabricating an electrospun membrane dispersed with boron nitride nanotubes. The PLLA/Gelatine/PDA@BNNT (PGBT) membrane has improved mechanical and biocompatible properties and generate piezovoltages of 130 mV when activated by ultrasound stimulation under 100 mW/cm2 without extra polarization. The PGBT with ultrasound is conducive to cellular osteogenesis, barrier function, and shows antibacterial rate of about 40 %. The rat cranial defect experiments revealed that PGBT with ultrasound could promote osteogenesis in-vivo and show great potentials for vertical bone defect repair.

Vertical and horizontal bone augmentation is one of the most challenging techniques in bone engineering. The use of barrier membranes and scaffolds in guided bone regeneration (GBR) procedures is a common approach for the treatment of lost bone around teeth and dental implants. The aim of this study was to estimate the barrier effects of a synthetic poly (lactic acid/caprolactone) [P(LA/CL)] bilayer membrane for GBR, compared to a porcine collagen bilayer membrane, in the vertical augmentation model on 10-12-months old rat skull without periosteum.

The hydroxyapatite (HAp) block (diameter: 4 mm, height: 3 mm, porosity:75%, average pore size:150 μm) was placed on the rat skull without a periosteum. The P(LA/CL) membrane (solid layer: 25 μm, porous layer: 175 μm) or the collagen membrane (solid layer, porous layer) was applied onto the HAp block. At 3, 6, and 12 weeks after the surgery, the incised tissues were fixed, decalcified, and stained with hematoxylin and eosin for histological evaluation.

The P(LA/CL) membrane remained until 12 weeks and could achieve barrier effects to inhibit cellular invasion from the repositioned soft tissues. Local bone formation occurred in the interconnected pores of HAp at 6 weeks. On the other hand, the collagen membrane did not inhibit cellular invasion for its expansion until 3 weeks, and was absorbed until 6 weeks. Histomorphometrically, bone in the P(LA/CL)/HAp at 6 and 12 weeks occupied 8.3 % and 10.0 %, respectively, while bone was not formed in the pores of the upper half area in the collagen/HAp.

The results in the biomimetic model indicated that the P(LA/CL) membrane might be effective in GBR as an occlusive and absorbable membrane. Key words:Guided bone regeneration (GBR), bone, augmentation, absorbable, membrane, collagen, hy-droxyapatite; P(LA/CL), biomimetic.

Background/Objectives: The use of titanium meshes in bone regeneration is a clinical procedure that regenerates bone defects by ensuring graft stability and biocompatibility. The aim of the present investigation was to evaluate the clinical effectiveness of titanium mesh procedures in terms of vertical bone gain and the exposure rate. Methods: The product screening and eligibility analysis were performed using the Pubmed/MEDLINE, EMBASE, and Google Scholar electronic databases by two authors. The selected articles were classified based on the study design, regenerative technique, tested groups and materials, sample size, clinical findings, and follow-up. A risk of bias calculation was conducted on the selected randomized controlled trials (RCTs) and non-randomized trials and a series of pairwise meta-analysis calculations were performed for the vertical bone gain (VBG) and exposure rate. A significantly lower exposure rate was observed using coronally advanced lingual flaps (p < 0.05). No difference was observed between the titanium mesh and GBR techniques in terms of VBG (p > 0.05). Results: The initial search output 288 articles, and 164 papers were excluded after the eligibility analysis. The descriptive synthesis considered a total of 97 papers and 6 articles were considered for the pairwise comparison. Conclusions: Within the limits of the present investigation, the titanium mesh procedure reported high VBG values after the healing period. The mesh exposure rate was drastically lower with passive management of the surgical flap.

To summarize the research progress of bioactive scaffolds in the repair and regeneration of osteoporotic bone defects.

Recent literature on bioactive scaffolds for the repair of osteoporotic bone defects was reviewed to summarize various types of bioactive scaffolds and their associated repair methods.

The application of bioactive scaffolds provides a new idea for the repair and regeneration of osteoporotic bone defects. For example, calcium phosphate ceramics scaffolds, hydrogel scaffolds, three-dimensional (3D)-printed biological scaffolds, metal scaffolds, as well as polymer material scaffolds and bone organoids, have all demonstrated good bone repair-promoting effects. However, in the pathological bone microenvironment of osteoporosis, the function of single-material scaffolds to promote bone regeneration is insufficient. Therefore, the design of bioactive scaffolds must consider multiple factors, including material biocompatibility, mechanical properties, bioactivity, bone conductivity, and osteogenic induction. Furthermore, physical and chemical surface modifications, along with advanced biotechnological approaches, can help to improve the osteogenic microenvironment and promote the differentiation of bone cells.

With advancements in technology, the synergistic application of 3D bioprinting, bone organoids technologies, and advanced biotechnologies holds promise for providing more efficient bioactive scaffolds for the repair and regeneration of osteoporotic bone defects.

This study investigates the mechanical properties as well as in vitro and in vivo cyto- and biocompatibility of collagen membranes cross-linked with glutaraldehyde (GA), proanthocyanidins (PC), hexamethylendiisocyanate (HMDI) and 1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide (EC/NHS). A non-crosslinked membrane was used as reference control (RF). The initial in vitro cytotoxic analyses revealed that the PC, EC, and HMDI crosslinked membranes were cytocompatible, while the GA crosslinked membrane was cytotoxic and thus selected as positive control in the further in vivo study. Cross-linking enhances the tensile strength and collagenase resistance, effectively prolonging the membrane's standing time in vivo. Using (immune-) histochemistry and histomorphometrical analyses, the cellular inflammatory responses, tissue integration and vascularization patterns at 10-, 30-, and 90-day post-implantation in a subcutaneous implantation model in rats were analyzed. The PC membrane elicited the mildest inflammatory cell levels, akin to the RF membrane, while other groups induced an M1-dominated macrophage response and numerous multinucleated giant cells throughout the study period. EC membranes maintained structural stability up to 30 days post-implantation, similar to the GA group, whereas others collapsed prematurely. Concurrent with membrane collapse, transmembrane vascularization occurred across all groups. Histopathological and histomorphometry results reveal the intricate interplay of inflammatory cell populations in vascularization. These findings offer valuable insights into the pivotal role of cross-linkers in modulating mechanical properties and tissue responses of collagen membranes.

BACKGROUND This study included 32 patients with single missing teeth and alveolar bone defects and aimed to compare outcomes from guided bone regeneration with a gelatin/polylactic acid (GT/PLA) barrier membrane and a Guidor® bioresorbable matrix barrier dental membrane. MATERIAL AND METHODS A total of 32 participants were recruited in the clinical study, with single missing teeth and alveolar bone defects, requiring guided bone regeneration (32 missing teeth in total). They were randomly divided into the GT/PLA membrane group (experimental) and Guidor® membrane group (control) by the envelope method (n=16). Both membranes were used intraoperatively to cover the bone substitute material. Cone beam computed tomography (CBCT) was performed immediately and at 6 months after surgery to assess the amount of bone resorption. In addition, the osteogenic efficacy was calculated. The soft tissue index (STI), wound healing, membrane exposure, and incidence of infection in the operative area were evaluated. RESULTS The implant survival rate was 100% in both groups. The average bone resorption was 148.54±107.42 mm³ in the experimental group and 185.25±85.31 mm³ in the control group (P=0.163); the osteogenic efficacy was 75% in the experimental group and 56% in the control group (P=0.458). Moreover, the parameters of STI, wound healing, membrane exposure, and incidence of infection in the operative area showed no statistically significant difference between the 2 groups (P>0.05). CONCLUSIONS The GT/PLA barrier membrane yielded non-inferior clinical and imaging results to the GUIDOR® membrane, exhibiting good efficacy and biocompatibility in GBR.

At present, there is a significant population of individuals experiencing bone deficiencies caused by injuries, ailments affecting the bones, congenital abnormalities, and cancer. The management of substantial bone defects a significant global orthopedic challenge due to the intricacies involved in promoting and restoring the growth of fresh osseous tissue. Autografts are widely regarded as the "gold standard" for repairing bone defects because of their superior tissue acceptance and ability to control osteogenesis. However, patients undergoing autografts may encounter various challenges, including but not limited to hernia, bleeding, nerve impairment, tissue death. Therefore, researchers in regenerative medicine are striving to find alternatives. Collagen is the most abundant protein in the human body, and its triple helix structure gives it unique characteristics that contribute to its strength and functionality in various tissues. Collagen is commonly processed into various forms such as scaffolds, sponges, membranes, hydrogels, and composite materials, due to its unique compatibility with the human body, affinity for water, minimal potential for immune reactions, adaptability, and ability to transport nutrients or drugs. As an alternative material in the field of bone regeneration, collagen is becoming increasingly important. The objective of this review is to provide a comprehensive analysis of the primary types and sources of collagen, their processes of synthesis and degradation, as well as the advancements made in bone regeneration research and its potential applications. A comprehensive investigation into the role of collagen in bone regeneration is undertaken, providing valuable points of reference for a more profound comprehension of collagen applications in this field. The concluding section provides a comprehensive overview of the prospective avenues for collagen research, underscoring their promising future and highlighting their significant potential in the field of bone regeneration. The Translational Potential of this Article. The comprehensive exploration into the diverse functions and translational potential of collagen in bone regeneration, as demonstrated in this review, these findings underscore their promising potential as a treatment option with significant clinical implications, thus paving the way for innovative and efficacious therapeutic strategies in this domain.

With the implementation of bone substitute materials, regeneration strategies have inevitably evolved over the years. Histomorphometry is the optimal means of quantitative evaluation of bone structure and morphology. This systematic review focuses on determining study models, staining methods and histomorphometric parameters used for bone regeneration research on non-decalcified plastic-embedded specimens over the last 10 years. After being subjected to the inclusion and exclusion criteria, 118 studies were included in this review. The results establish the most commonly selected animal model is rat, followed by rabbit, sheep and dog. Strong preference for staining samples with toluidine blue was noted. With regard to histomorphometric parameters, terms related to bone were most frequently assessed, amounting to almost half of recorded parameters. New bone formation was the main descriptor of this category. Residual bone graft and non-bone tissue parameters were also often evaluated. With regard to dynamic histomorphometry, mineral apposition rate (MAR) was the parameter of choice for most researchers, with calcein green being the preferred dye for fluorochrome labelling. An overview of the contemporary literature, as well as weaknesses in the current research protocols have been discussed.

(1) Background: Collagen, a natural polymer, is widely used in the fabrication of membranes for guided bone regeneration (GBR). These membranes are sourced from various tissues, such as skin, pericardium, peritoneum, and tendons, which exhibit differences in regenerative outcomes. Therefore, this study aimed to evaluate the morphological and chemical properties of porcine collagen membranes from five different tissue sources: skin, pericardium, dermis, tendons, and peritoneum. (2) Methods: The membrane structure was analyzed using energy-dispersive X-ray spectrometry (EDX), variable pressure scanning electron microscopy (VP-SEM), Fourier transform infrared spectroscopy (FTIR), and thermal stability via thermogravimetric analysis (TGA). The absorption capacity of the membranes for GBR was also assessed using an analytical digital balance. (3) Results: The membranes displayed distinct microstructural features. Skin- and tendon-derived membranes had rough surfaces with nanopores (1.44 ± 1.24 µm and 0.46 ± 0.1 µm, respectively), while pericardium- and dermis-derived membranes exhibited rough surfaces with macropores (78.90 ± 75.89 µm and 64.89 ± 13.15 µm, respectively). The peritoneum-derived membrane featured a rough surface of compact longitudinal fibers with irregular macropores (9.02 ± 3.70 µm). The thickness varied significantly among the membranes, showing differences in absorption capacity. The pericardium membrane exhibited the highest absorption, increasing by more than 10 times its initial mass. In contrast, the skin-derived membrane demonstrated the lowest absorption, increasing by less than 4 times its initial mass. Chemical analysis revealed that all membranes were primarily composed of carbon, nitrogen, and oxygen. Thermogravimetric and differential scanning calorimetry analyses showed no significant compositional differences among the membranes. FTIR spectra confirmed the presence of collagen, with characteristic peaks corresponding to Amide A, B, I, II, and III. (4) Conclusions: The tissue origin of collagen membranes significantly influences their morphological characteristics, which may, in turn, affect their osteogenic properties. These findings provide valuable insights into the selection of collagen membranes for GBR applications.

To assess the clinical and radiographic outcomes of alveolar ridge augmentation using a novel three-dimensional printed individualized titanium mesh (3D-PITM) for guided bone regeneration (GBR).

Preoperative cone-beam computed tomography (CBCT) was used to evaluate alveolar ridge defects, followed by augmentation with high-porosity 3D-PITM featuring circular and spindle-shaped pores. Postoperative CBCT scans were taken immediately and after 6 months of healing. These scans were compared with preoperative scans to calculate changes in bone volume, height, and width, along with the corresponding resorption rates. A statistical analysis of the results was then conducted.

A total of 21 patients participated in the study, involving alveolar ridge augmentation at 38 implant sites. After 6 months of healing, the average bone augmentation volume of 21 patients remained at 489.71 ± 252.53 mm3, with a resorption rate of 16.05% ± 8.07%. For 38 implant sites, the average vertical bone increment was 3.63 ± 2.29 mm, with a resorption rate of 17.55% ± 15.10%. The horizontal bone increment at the designed implant platform was 4.43 ± 1.85 mm, with a resorption rate of 25.26% ± 15.73%. The horizontal bone increment 2 mm below the platform was 5.50 ± 2.48 mm, with a resorption rate of 16.03% ± 9.57%. The main complication was exposure to 3D-PITM, which occurred at a rate of 15.79%.

The novel 3D-PITM used in GBR resulted in predictable bone augmentation. Moderate over-augmentation in the design, proper soft tissue management, and rigorous follow-ups are beneficial for reducing the graft resorption and the incidence of exposure.

An oroantral communication may form in the upper molar region after tooth extraction. The patient is a 59-year-old female, who is a nonsmoker. At the initial visit, teeth #14, #15, and #17 were missing. After tooth #16 was extracted due to apical periodontitis, a bone defect with a diameter of approximately 4 mm was observed, leading to the formation of an oroantral fistula (OAF). Another window was created in the lateral wall adjacent to the superior part of the bone defect at the fistula site to achieve closure of the OAF through bone formation and simultaneously perform sinus floor elevation (lateral approach) for implant placement. Through this lateral window, instruments were inserted into the maxillary sinus towards the bone defect at the fistula site. During this process, the remaining bone between the lateral window and the bone defect at the fistula site was carefully removed with instruments, connecting the two bone defects to facilitate manipulation of the instruments. The Schneiderian membrane was elevated without enlarging the tear. Six months after these surgeries, a cone beam computerized tomography (CBCT) scan confirmed the closure of the fistula with hard tissue and the elevation of the sinus floor. Subsequently, three implants were placed, and prosthetic treatment was completed. Follow-up data is provided, including periapical X-ray and CBCT images taken 2 years and 3 months after surgery (1 year and 3 months after the placement of the final prosthetic structure). The progress so far has been favorable.

This study aimed to evaluate the impact of different collagen membran fixation protocols on the volume stability in horizontal ridge augmentation in the aesthetic area.

A total of 48 patients with 65 augmented sites were included in this study. Implants were placed in the aesthetic region, and simultaneous guided bone regeneration (GBR) surgery was performed for horizontal ridge augmentation. Participants were divided into four groups, each comprising 12 patients, based on different absorbable collagen membrane fixation protocols. Group 1: without fixation; Group 2: fixation with absorbable sutures; Group 3: fixation with titanium pins; Group 4: fixation with titanium pins and absorbable sutures. Cone beam computed tomography (CBCT) was performed immediately after surgery and at 6 months post-surgery, respectively. The horizontal thickness of the augmented region was analyzed for volume stability at the implant shoulder (H0) and 1-5 mm apical to the implant shoulder (H1-H5). Changes in labial thickness during bone healing were calculated as absolute values (mm) and relative values (%).

After 6 months of bone healing, horizontal thickness was significantly reduced at all levels (H0-H5) in all groups compared to immediate post-surgery results (p < 0.05). At H1-H5, horizontal bone loss in group 1 was significantly higher than in the other three groups (p < 0.05). Group 4 exhibited significantly less horizontal bone loss compared to group 2 at H0-H2 (p < 0.05) and group 4 compared to group 3 at H0-H1 (p < 0.05). No significant difference in horizontal bone loss between groups 2 and 3 was detected at H0-H5 (p > 0.05).

Guided bone regeneration in the aesthetic area with additional membrane fixation demonstrated superior volume stability of the augmented region compared to cases without fixation. There was no significant difference in bone volume stability between membrane fixation with titanium pins and fixation with absorbable sutures. However, the combined use of pins and absorbable sutures yielded superior volume stability.

Collagen membranes play a crucial role in guided bone regeneration (GBR) by preventing soft tissue infiltration and maintaining space for bone formation. This study investigated the impact of collagen membrane flexibility on GBR outcomes through in vitro and in vivo analyses. Flexible (0.3 mm in width) and stiff (0.5 mm in width) porcine collagen membranes were compared. In vitro tests assessed hydrophilicity, enzymatic degradation, conformability, space maintenance, and tensile strength. An in vivo study using a canine model evaluated bone regeneration in standardized mandibular defects filled with deproteinized porcine bone mineral and covered with no membrane, flexible membrane, or stiff membrane. Micro-computed tomography and histomorphometric analyses were performed at 8 and 16 weeks. The flexible membrane demonstrated superior hydrophilicity, faster enzymatic degradation, and greater conformability in vitro. In vivo, micro-computed tomography analysis revealed similar alveolar ridge widths across all groups. Histomorphometric analysis at 16 weeks showed significantly larger regenerated areas in the flexible membrane group compared to controls in coronal, middle, and apical regions. Both membrane groups exhibited higher regeneration ratios than controls, with significant differences in the coronal area. The flexible membrane group demonstrated significantly higher new bone formation in all regions compared to controls at 16 weeks. These findings suggest that flexible membrane substantially enhances GBR outcomes by increasing hydrophilicity and conformability. The study highlights the potential clinical benefits of incorporating flexible membranes in GBR procedures for improved bone regeneration outcomes.

Background/Objectives: The primary aim of this retrospective clinical study was to assess the success and bone gain achieved by using the Fibrinogen-Induced Regeneration Sealing Technique (F.I.R.S.T.) in different indications. Methods: In this single-center retrospective clinical study, F.I.R.S.T. was performed in the following indications: alveolar ridge preservation (ARP), immediate implant placement, and horizontal and vertical guided bone regeneration (GBR) with simultaneous dental implant placement. F.I.R.S.T. is a modified approach to GBR characterized by the application of a porcine cortical lamina, as a long-term resorbable bone barrier to cover the bone defect, and a fibrin sealant for easy adaptation of the xenogenic bone graft material and the fixation of the collagenic bone barrier. Patients with uncontrolled systemic diseases, medications, or diseases that may alter bone metabolism; local inflammation; poor oral hygiene; and heavy smoking were excluded from this study. Horizontal and vertical bone gain (HBG and VBG) were measured by comparing postoperative and preoperative cone beam computed tomography (CBCT) reconstructions. Patients were recalled for controls and oral hygiene treatment every 6 months. Results: Altogether, 62 patients (27 male, 35 female, age 63.73 ± 12.95 years) were included in this study, and 105 implants were placed. Six implants failed during the 50.67 ± 22.18-month-long follow-up. Cumulative implant survival throughout the groups was 94.29 %. In the immediate implant group, HBG was 0.86 mm (range: -0.75-8.19 mm) at the 2 mm subcrestal level, while VBG was 0.87 ± 1.21 mm. In the ARP group, HBG was 0.51 mm (range: -0.29-3.90 mm) at the 2 mm subcrestal level, while VBG was -0.16 mm (range: -0.52-0.92 mm). In the horizontal GBR group, HBG was 2.91 mm (range: 1.24-8.10 mm) at the 2 mm subcrestal level. In the vertical GBR group, VBG was 4.15 mm (range: 3.00-10.41 mm). Conclusions: F.I.R.S.T. can be utilized successfully for bone augmentation. The vertical and horizontal bone gains achieved through F.I.R.S.T. allow for implant placement with adequate bone width on both the vestibular and oral aspects of the implant.

Alveolar ridge loss presents difficulties for implant placement and stability. To address this, alveolar ridge preservation (ARP) is required to maintain bone and avoid the need for ridge augmentation using socket grafting. In this study, a scaffold for ARP was created by fabricating a 3D porous dense microfiber silk fibroin (mSF) embedded in poly(vinyl alcohol) (PVA), which mimics the osteoid template. The research utilized a freeze-thawing technique to create a mimicked osteoid 3D porous scaffold by incorporating different amounts of mSF into the PVA, namely, 1%, 3%, 5% and 7%. Subsequently, a 3D profilometer machine and a scanning electron microscope were employed to examine the morphology and size of the mSF and the mimicked osteoid 3D porous scaffold in all groups. Thermal characteristics and crystalline structure were analyzed before assessing the water contact angle, swelling behavior, degradation and mechanical properties. The experiment evaluated the biological performance of the mimicked osteoid 3D porous scaffold by examining the efficacy of osteoblast cell adhesion, proliferation, viability, protein synthesis, alkaline phosphatase (ALP) activity and calcium synthesis. Finally, the ability of osteoblast cells to regulate the osteoid matrix deposition on the osteoid 3D porous scaffold was assessed by mimicking the dynamic bone environment using rat mesenchymal stem cells. The findings suggest that incorporating mSF into PVA enhances the interconnective pore size, crystalline structure and thermal behavior of the mimicked osteoid 3D porous scaffold. The hydrophilicity of PVA decreased with an increase in the proportion of mSF, while a higher proportion of mSF resulted in increased swelling and mechanical characteristics. Incorporating a greater proportion of mSF, specifically 5% and 7%, led to a reduced rate of degradation. The addition of 5% mSF to the PVA 3D porous scaffold resulted in remarkable biological properties and excellent osteoconductive activity.

Objectives: The aim of this matched prospective cohort study was to examine the microarchitecture of the augmented bone following a modified alveolar ridge splitting procedure and compare it to that of native bone. Methods: In the test group, patients underwent a modified ridge split osteotomy procedure to restore the width of the posterior segment of the mandible. Patients with sufficient bone width for dental implant placement in the posterior region of the mandible following 3-month-long spontaneous healing after tooth removal were included in the control group. In both study groups, bone biopsy samples were harvested and dental implants were placed. Histomorphometry and micro-CT analysis were performed. Results: Altogether, 15 patients were included in this study (7 patients in the test group, with 14 bone core biopsies harvested, and 8 patients in the control group, with 13 bone core biopsies harvested). Percentage bone volume (BV/TV) in the micro-CT analysis (22.088 ± 8.094% and 12.075 ± 4.009% for the test and control group, respectively) showed statistically significant differences between study groups. Conclusions: Based on histological and micro-CT analyses, the modified ridge splitting procedure with autologous bone block harvested from the retromolar area results in a dental implant recipient bone microarchitecture superior to that of the extraction sockets left to heal undisturbed for a 3-month-long healing period.

Guided bone regeneration (GBR) is an extensively used technique for the treatment of maxillofacial bone defects and bone mass deficiency in clinical practice. However, to date, studies on membranes for GBR have not achieved the combination of suitable properties and cost-effective membrane production. Herein, we developed a polycaprolactone/human extracellular matrix-like collagen (PCL/hCol) membrane with an asymmetric porous structure via the nonsolvent-induced phase separation (NIPS) method, which is a highly efficient procedure with simple operation, scalable fabrication and low cost. This membrane possessed a porous rough surface, which is conducive to cell attachment and proliferation for guiding osteogenesis, together with a relatively smooth surface with micropores, which allows the passage of nutrients and is unfavorable for the adhesion of cells, thus preventing fibroblast invasion and overall meeting the demands for GBR. Besides, we evaluated the characteristics and biological properties of the membrane and compared them with those of commercially available membranes. Results showed that the PCL/hCol membrane exhibited excellent mechanical properties, degradation characteristics, barrier function, biocompatibility and osteoinductive potential. Furthermore, our in vivo study demonstrated the promotive effect of the PCL/hCol membrane on bone formation in rat calvarial defects. Taken together, our NIPS-prepared PCL/hCol membrane with promising properties and production advantages offers a new perspective for its development and potential use in GBR application.

Collagen-based membrane is the most commonly used biomaterial for guided bone and tissue regeneration; however, its barrier function can be threatened by its rapid degradation pattern, affecting the success of the regeneration process. Differences in the origin and functionalization of the membrane to obtain better properties can alter the degradation rate. The objective of this study was to examine the biodegradation pattern of two commercially available collagen membranes (Jason® and Collprotect®) manufactured using porcine pericardium or dermis, doped or not with zinc-ions or doxycycline, in a period up to 21 days. The membrane specimens were subjected to hydrolytic and bacterial degradation tests. The different immersion times were carried out from 12 h up to 21 days. At each time point, quantitative measurements of thickness and weight were made using a digital caliper and an analytic microbalance, respectively. ANOVA and Student-Newman-Keuls tests were carried out for comparison purposes (p < 0.05). The differences between time-points within the same membranes and solutions were assessed by pairwise comparisons (p < 0.001). Unfunctionalized Jason membrane made of porcine pericardium attained the highest resistance to both degradation tests. The functionalization of the membranes did not alter the biodegradation patterns. All the membranes completely degraded before 48 h in the bacterial collagenase solution, which was the most aggressive test.

Several nanomaterials have been recently used to overcome various challenges in the dental domain. Bioactive glasses, a class of bioceramics, with their outstanding properties including but not limited to their strong biocompatibility, antibacterial characteristics, and bioactivity inside the body's internal milieu have made them valuable biomaterials in a variety of dental domains. The utilization of nanomaterials has improved the performance of teeth, and the incorporation of bioactive glasses has the field of dentistry at an unsurpassed level in different categories such as esthetic and restorative dentistry, periodontics and dental implants, orthodontics, and endodontics. The current study discusses the most recent developments of the bioactive glasses' creation and implementation for dental applications, as well as the challenges and opportunities still facing the field. This work provides an overview of the current obstacles and potential future prospects for bioactive glasses-based nanocomposites to improve their dental uses. It also emphasizes the great potential synergistic effects of bioactive glasses used with other nanomaterials for dental applications.

Scaffolds with multiphasic structures are considered to be superior for guided tissue regeneration. Two types of tilapia skin collagen gradient membranes (stepped gradient and linear gradient) with multiphasic structures were prepared by controlling the collagen concentrations and the freezing rates. The results revealed that collagen gradient membranes were more capable of guiding tissue regeneration compared to homogeneous membranes. These two gradient membranes featured a dense outer layer and a loose inner layer, with good mechanical properties as indicated by tensile strengths of more than 250 Kpa and porosities exceeding 85 %. Additionally, these membranes also showed good hydrophilicity and water absorption, with an inner layer contact angle of less than 91° and a water absorption ratio greater than 40 times. Furthermore, the multiphasic scaffolds were proved to be biocompatible by the acute toxicity assay, the intradermal irritation test and so on. Gradient membranes could effectively promote the adhesion and proliferation of fibroblasts and osteoblasts, through elevating the TGF-β/Smad signaling pathway by TGF-β and Smads, and activating the Wnt/β-catenin signaling pathway by LRP5 and β-catenin, similar to homogenous membranes. Therefore, collagen gradient membranes from tilapia skin show important application value in guiding tissue regeneration.

The mechanical competence and suturing ability of collagen-based membranes are paramount in guided bone regeneration (GBR) therapy, to ensure damage-free implantation, fixation and space maintenancein vivo. However, contact with the biological medium can induce swelling of collagen molecules, yielding risks of membrane sinking into the bone defect, early loss of barrier function, and irreversibly compromised clinical outcomes. To address these challenges, this study investigates the effect of the crosslinked network architecture on both mechanical and suture-holding properties of a new atelocollagen (AC) membrane. UV-cured networks were obtained via either single functionalisation of AC with 4-vinylbenzyl chloride (4VBC) or sequential functionalisation of AC with both 4VBC and methacrylic anhydride. The wet-state compression modulus (Ec) and swelling ratio (SR) were significantly affected by the UV-cured network architecture, leading up to a three-fold reduction in SR and about two-fold increase inEcin the sequentially functionalised, compared to the single-functionalised, samples. Electron microscopy, dimensional analysis and compression testing revealed the direct impact of the ethanol series dehydration process on membrane microstructure, yielding densification of the freshly synthesised porous samples and a pore-free microstructure with increasedEc. Nanoindentation tests via spherical bead-probe atomic force microscopy (AFM) confirmed an approximately two-fold increase in median (interquartile range (IQR)) elastic modulus in the sequentially functionalised (EAFM= 40 (13) kPa), with respect to single-functionalised (EAFM= 15 (9) kPa), variants. Noteworthy, the single-functionalised, but not the sequentially functionalised, samples displayed higher suture retention strength (SRS = 28 ± 2-35 ± 10 N∙mm-1) in both the dry state and following 1 h in phosphate buffered saline (PBS), compared to Bio-Gide® (SRS: 6 ± 1-14 ± 2 N∙mm-1), while a significant decrease was measured after 24 h in PBS (SRS= 1 ± 1 N∙mm-1). These structure-property relationships confirm the key role played by the molecular architecture of covalently crosslinked collagen, aimed towards long-lasting resorbable membranes for predictable GBR therapy.

Collagen barrier membranes are frequently used in guided tissue and bone regeneration. The aim of this study was to analyze the signature of human serum proteins adsorbed onto collagen membranes using a novel protein extraction method combined with mass spectrometry. Native porcine-derived collagen membranes (Geistlich Bio-Gide®, Wolhusen, Switzerland) were exposed to pooled human serum in vitro and, after thorough washing, subjected to protein extraction either in conjunction with protein enrichment or via a conventional surfactant-based method. The extracted proteins were analyzed via liquid chromatography with tandem mass spectrometry. Bioinformatic analysis of global profiling, gene ontology, and functional enrichment of the identified proteins was performed. Overall, a total of 326 adsorbed serum proteins were identified. The enrichment and conventional methods yielded similar numbers of total (315 vs. 309), exclusive (17 vs. 11), and major bone-related proteins (18 vs. 14). Most of the adsorbed proteins (n = 298) were common to both extraction groups and included several growth factors, extracellular matrix (ECM) proteins, cell adhesion molecules, and angiogenesis mediators involved in bone regeneration. Functional analyses revealed significant enrichment of ECM, exosomes, immune response, and cell growth components. Key proteins [transforming growth factor-beta 1 (TGFβ1), insulin-like growth factor binding proteins (IGFBP-5, -6, -7)] were exclusively detected with the enrichment-based method. In summary, native collagen membranes exhibited a high protein adsorption capacity in vitro. While both extraction methods were effective, the enrichment-based method showed distinct advantages in detecting specific bone-related proteins. Therefore, the use of multiple extraction methods is advisable in studies investigating protein adsorption on biomaterials.

The alveolar ridge split (ARS) technique is a pivotal advancement in dental implantology, addressing the limitation of insufficient bone width for implant placement. This review traces the historical development of ARS from its initial conceptualization to current practices and future directions. Emphasizing the technique's development, indications, procedural overview, and osteotomy variations, we highlight its minimally invasive nature, which reduces patient morbidity and treatment time. This article reviews various osteotomy methods within ARS, examining their applications, benefits, and limitations. Furthermore, it discusses the technique's role in expanding treatment options for patients with compromised alveolar structures, underpinned by a high implant survival rate and the potential for immediate implant placement. We also cover the necessity of meticulous surgical technique, the importance of patient-specific factors, and the promising future of ARS facilitated by advancements in biomaterials and regenerative medicine. In summary, this review provides a comprehensive overview of ARS, offering valuable insights for dental professionals and informing future clinical practices and research in implantology.

Alveolar bone defects caused by tumor, trauma and inflammation can lead to the loss of oral function and complicate denture restoration. Currently, guided bone regeneration (GBR) barrier membranes for repairing bone defect cannot effectively promote bone regeneration due to their unstable degradation rate and poor antibacterial properties. Furthermore, they require additional tailoring before implantation. Therefore, this study developed a visible light-curing hydrogel membrane (CF-Cu) comprising methacrylated carboxymethyl chitosan (CMCS-MA), silk fibroin (SF), and copper nanoparticles (Cu NPs) to address these shortcomings of commercial membranes. The CF-Cu hydrogel, characterized by scanning electron microscopy (SEM), a universal testing machine, and swelling and degradation tests, demonstrated a smooth porous network structure, suitable swelling ratio, biodegradability, and enhanced mechanical strength. Cytotoxicity and hemolysis tests in vitro demonstrated excellent cyto- and hemo-compatibility of the CF-Cu hydrogel extracts. Additionally, evaluation of antibacterial properties in vitro, including colony forming unit (CFU) counts, MTT assays, and live/dead fluorescence staining, showed that the CF-Cu hydrogel exhibited excellent antibacterial properties, inhibiting over 80% of S. aureus, S. mutans, and P. gingivalis with CF-1Cu hydrogel compared to the control group. Moreover, evaluation of osteogenic differentiation of rBMSCs in vitro suggested that the CF-1Cu hydrogel significantly improved alkaline phosphatase (ALP) activity and the mineralization of extracellular matrix, up-regulating the expressions of osteogenesis-related genes (Runx2, ALP, Col-1, OPN and BSP). In summary, these results indicated that CF-1Cu hydrogel exhibited excellent cytocompatibility, antibacterial and osteogenic properties in vitro. Therefore, the CF-1Cu hydrogel holds potential as a viable material for application in GBR procedures aimed at addressing bone defects.

Biomaterials have been the subject of extensive research, and their applications in medicine and pharmacy are expanding rapidly. Collagen and its derivatives stand out as valuable biomaterials due to their high biocompatibility, biodegradability, and lack of toxicity and immunogenicity. This review comprehensively examines collagen from various sources, its extraction and processing methods, and its structural and functional properties. Preserving the native state of collagen is crucial for maintaining its beneficial characteristics. The challenges associated with chemically modifying collagen to tailor its properties for specific clinical needs are also addressed. The review discusses various collagen-based biomaterials, including solutions, hydrogels, powders, sponges, scaffolds, and thin films. These materials have broad applications in regenerative medicine, tissue engineering, drug delivery, and wound healing. Additionally, the review highlights current research trends related to collagen and its derivatives. These trends may significantly influence future developments, such as using collagen-based bioinks for 3D bioprinting or exploring new collagen nanoparticle preparation methods and drug delivery systems.

Guided bone regeneration facilitates the growth of new bone in areas where there is a bone defect or insufficiency. This technique involves placing a barrier membrane over the bone graft site, and the membrane prevents the invasion of soft tissue (such as gingival tissue) into the bone graft area. This allows the slower-growing bone cells to populate the area without competition, promoting proper bone regeneration. When combined, chitosan and gelatin create composite scaffolds that leverage the strengths of both materials. Chitosan provides structural integrity and antimicrobial properties, and gelatin enhances cell attachment and proliferation, which improves mechanical properties and makes it more suitable for supporting bone regeneration in load-bearing areas. This systematic review aims to evaluate the effectiveness of chitosan and gelatin-based scaffolds in bone regeneration. Various databases such as PubMed, Cochrane Library, LILAC, and Google Scholar were screened to adhere to the eligibility criteria. The included studies in the review were the in vivo and in vitro assessment of the chitosan and gelatin efficiency as a scaffold. Six studies were investigated for the involvement of chitosan and gelatin-based scaffolds in bone regeneration. Of these, two in vivo studies examined bone regeneration by measuring alkaline phosphatase activity (ALP) using different staining techniques, while the remaining four in vitro studies used histologic and histometric analysis where stem cells, chemicals, and other biopolymers were compared. Chitosan and gelatin scaffolds consistently showed better results in terms of bone repair throughout all six experiments. Gelatin's capacity for regeneration can be increased by mixing it with chitosan. For additional advancement, future researchers need to focus on incorporating biopolymers. The potential of scaffolds composed of gelatin and chitosan to replace tissue lost due to periodontitis shows great clinical significance.

Periodontitis is a chronic inflammatory disease primarily caused by dental plaque, which is a significant global public health concern due to its high prevalence and severe impact on oral, and even systemic diseases. The current therapeutic plan focuses on three objectives: pathogenic bacteria inhibition, inflammation control, and osteogenic differentiation induction. Existing treatments still have plenty of drawbacks, thus, there is a pressing need for novel methods to achieve more effective treatment effects. Nanomaterials, as emerging materials, have been proven to exert their inherent biological properties or serve as stable drug delivery platforms, which may offer innovative solutions in periodontitis treatment. Nanomaterials utilized in periodontitis treatment fall into two categories, organic and inorganic nanomaterials. Organic nanomaterials are known for their biocompatibility and their potential to promote tissue regeneration and cell functions, including natural and synthetic polymers. Inorganic nanomaterials, such as metal, oxides, and mesoporous silica nanoparticles, exhibit unique physicochemical properties that make them suitable as antibacterial agents and drug delivery platforms. The inorganic nanosurface provides terrain induction for cell migration and osteogenic regeneration at defect sites by introducing different surface morphologies. Inorganic nanomaterials also play a role in antibacterial photodynamic therapy (aPDT) for eliminating pathogenic bacteria in the oral cavity. In this review, we will introduce multiple forms and applications of nanomaterials in periodontitis treatment and focus on their roles in addressing the key therapeutic objectives, to emphasize their promising future in achieving more effective and patient-friendly approaches toward periodontal tissue regeneration and overall health.

Advanced periodontitis poses a significant threat to oral health, causing extensive damage and loss of both hard and soft periodontal tissues. While traditional therapies such as scaling and root planing can effectively halt the disease's progression, they often fail to fully restore the original architecture and function of periodontal tissues due to the limited capacity for spontaneous regeneration. To address this challenge, periodontal tissue engineering has emerged as a promising approach. This technology centers on the utilization of biomaterial scaffolds, which function as three-dimensional (3D) templates or frameworks, supporting and guiding the regeneration of periodontal tissues, including the periodontal ligament, cementum, alveolar bone, and gingival tissue. These scaffolds mimic the extracellular matrix (ECM) of native periodontal tissues, aiming to foster cell attachment, proliferation, differentiation, and, ultimately, the formation of new, functional periodontal structures. Despite the inherent challenges associated with preclinical testing, the intensification of research on biomaterial scaffolds, coupled with the continuous advancement of fabrication technology, leads us to anticipate a significant expansion in their application for periodontal tissue regeneration. This review comprehensively covers the recent advancements in biomaterial scaffolds engineered specifically for periodontal tissue regeneration, aiming to provide insights into the current state of the field and potential directions for future research.

The periodontium is a complex hierarchical structure composed of alveolar bone, periodontal ligament, cementum, and gingiva. Periodontitis is an inflammatory disease that damages and destroys the periodontal tissues supporting the tooth. Periodontal therapies aim to regenerate the lost tissues, yet current treatments lack the integration of multiple structural/biochemical instructive cues to induce a coordinated regeneration, which leads to limited clinical outcomes. Hierarchical biomaterial scaffolds offer the opportunity to recreate the organization and architecture of the periodontium with distinct compartments, providing structural biomimicry that facilitates periodontal regeneration. Various scaffolds have been fabricated and tested preclinically, showing positive regenerative results. This review provides an overview of the recent research on hierarchical scaffolds for periodontal tissue engineering (TE). First, the hierarchical structure of the periodontium is described, covering the limitations of the current treatments used for periodontal regeneration and presenting alternative therapeutic strategies, including scaffolds and biochemical factors. Recent research regarding hierarchical scaffolds is highlighted and discussed, in particular, the scaffold composition, fabrication methods, and results from in vitro/in vivo studies are summarized. Finally, current challenges associated with the application of hierarchical scaffolds for periodontal TE are debated and future research directions are proposed.

Background: Guided bone regeneration (GBR) is a reliable technique used in vertical and horizontal bone defects. The posterior mandibular region is an area limited by anatomic constraints. The use of resorbable membranes with a cortical component could compensate for the lack of rigidity of resorbable membranes without the complications of non-resorbable membranes. The aim of this study was to evaluate the mean bone gains of a xenogeneic cortical membrane in horizontal and vertical bone defects in comparison with other membranes in the literature. Methods: A porcine cortical membrane was used to perform 7 GBR in the posterior mandibular region of five patients. Preoperative (T0) and six months postoperative (T1) cone beam computed tomography were superimposed to measure the horizontal and vertical bone gain. Implants were positioned at all sites, six months after GBR. Complications and bone resorption around the implants were also documented. Results: The mean horizontal and vertical bone gains were 3.83 ± 1.41 mm and 4.17 ± 1.86 mm, respectively. The analysis of repeatability was 0.997. As many as 40% of patients experienced pain refractory to analgesics. No exposure or infectious phenomenon was observed. Conclusions: This xenogeneic cortical membrane seemed to provide interesting results in the regeneration of horizontal and vertical bone defects. Comparative and prospective studies are necessary to validate the effectiveness of this membrane.

Assisted reproductive technologies are key to solving the problems of aging and organ defects. Collagen is compatible with living tissues and has many different chemical properties; it has great potential for use in reproductive medicine and the engineering of reproductive tissues. It is a natural substance that has been used a lot in science and medicine. Collagen is a substance that can be obtained from many different animals. It can be made naturally or created using scientific methods. Using pure collagen has some drawbacks regarding its physical and chemical characteristics. Because of this, when collagen is processed in various ways, it can better meet the specific needs as a material for repairing tissues. In simpler terms, collagen can be used to help regenerate bones, cartilage, and skin. It can also be used in cardiovascular repair and other areas. There are different ways to process collagen, such as cross-linking it, making it more structured, adding minerals to it, or using it as a carrier for other substances. All of these methods help advance the field of tissue engineering. This review summarizes and discusses the current progress of collagen-based materials for reproductive medicine.

Periodontitis is a bacteria-induced chronic inflammatory disease characterized by degradation of the supporting tissue and bone in the oral cavity. Treatment modalities seek to facilitate periodontal rehabilitation while simultaneously preventing further gingival tissue recession and potentially bone atrophy. The aim of this study was to compare two differently sourced membranes, a resorbable piscine collagen membrane and a porcine-derived collagen membrane, in the repair of soft tissue defects utilizing a preclinical canine model. This in vivo component consisted of 10 beagles which were subjected to bilateral maxillary canine mucogingival flap defects, as well as bilateral soft tissue defects (or pouches) with no periodontal ligament damage in the mandibular canines. Defects received either a piscine-derived dermal membrane, (Kerecis® Oral, Ísafjörður, Iceland) or porcine-derived dermal membrane (Geistlich Mucograft®, Wolhusen, Switzerland) in a randomized fashion (to avoid site bias) and were allowed to heal for 30, 60, or 90 days. Statistical evaluation of tissue thickness was performed using general linear mixed model analysis of variance and least significant difference (LSD) post hoc analyses with fixed factors of time and membrane. Semi-quantitative analysis employed for inflammation assessment was evaluated using a chi-squared test along with a heteroscedastic t-test and values were reported as mean and corresponding 95% confidence intervals. In both the mucogingival flap defects and soft tissue gingival pouches, no appreciable qualitative differences were observed in tissue healing between the membranes. Furthermore, no statistical differences were observed in the thickness measurements between piscine- and porcine-derived membranes in the mucogingival flap defects (1.05 mm [±0.17] and 1.29 mm [±0.17], respectively [p = .06]) or soft tissue pouches (1.36 mm [±0.14] and 1.47 mm [±0.14], respectively [p = .27]), collapsed over time. Independent of membrane source (i.e., piscine or porcine), similar inflammatory responses were observed in both the maxilla and mandible at the three time points (p = .88 and p = .79, respectively). Histologic and histomorphometric evaluation results indicated that both membranes yielded equivalent tissue responses, remodeling dynamics and healing patterns for the mucogingival flap as well as the soft tissue gingival pouch defect models.

Classical guided bone regeneration (GBR) treatments can achieve favorable clinical results for ridge defects. However, extensive bone augmentation in the non-esthetic area in the posterior region for minor ridge defects is unnecessary. Therefore, this study used a collagen and Platelet-rich fibrin (PRF) mixture for bone augmentation on minor posterior ridge defects and evaluated the effects.

22 Seibert Class I ridge defects were treated with BC and covered with a PRF membrane (simplified guided bone regeneration, simplified GBR) and other 22 were treated with Bio-Oss and covered with Bio-Gide (classical GBR). Cone-beam computed tomography imaging was conducted 6 months post-surgery to compare the ridge's horizontal width (HW) and buccal ridge's horizontal width to assess the osteogenic effect. In addition, the buccal ridge contour morphology was studied and classified.

The buccal ridge contour of simplified GBR was Type A in 14 cases, Type B in 7 cases, and Type C in 1 case and it of classical GBR was Type A in 11 cases, Type B in 8 cases, and Type C in 3 cases. The mean HW significantly increased by 1.50 mm of simplified GBR treatment, while it increased by 1.83 mm in classical GBR treatment.

The combined use of BC and PRF had a significant effect on bone augmentation and this treatment exhibited promising clinical results for correcting posterior Seibert Class I ridge defects. The morphological classification of the reconstructive effect in this study can be utilized in future clinical work.

Complications that occur after maxillary sinus floor augmentation (MSA) can be divided into early and late complications. Early complication is a side effect that occurs during the MSA procedure or during the initial healing period. Usually, late complication refers to a side effect that occurs after 3 weeks of MSA. However, in the longer term, there are cases that occur during the follow-up period after the prosthesis is delivered, and most of them present with peri-implantitis. In the present two cases, sinus graft complications occurred 1-2 years after prosthesis delivery but were independent of peri-implantitis and had atypical features showing asymptomatic results. Although the route of the infection source is unclear, the lesions were presumed to be caused by slow and delayed inflammation of oral bacteria infiltrating the bone graft area of the maxillary sinus. Within the limitations of present case reports, bone defects were successfully managed with a guided bone regeneration (GBR) procedure that included thorough defect degranulation, surface decontamination of exposed implant, and regrafting. Periodic monitoring of radiographic images is required for the detection of unusual sinus graft complications in sinus-augmented sites.

The aim of this study was to determine the effect of membrane fixation and combinations of bone substitute materials and barrier membranes on horizontal bone regeneration in peri-implant defects. Eight mongrel dogs underwent chronic buccal peri-implant dehiscence defects creation and were randomized into 4 groups: (a) deproteinized bovine bone mineral 1 (DBBM1) with a native collagen membrane (CM) (BB group, positive control group), (b) DBBM1 with native CM and 2 fixation pins (BBP group), (c) DBBM2 with a cross-linked CM (XC group), and (d) DBBM2 with cross-linked CM and 2 fixation pins (XCP group). Following 16 weeks of healing, tissues were radiographically and histomorphometrically analyzed. The total augmented area was significantly larger in the BBP, XC, and XCP groups compared to the BB group (4.27 ± 3.21, 7.17 ± 7.23, and 6.91 ± 5.45 mm2 versus 1.35 ± 1.28 mm2, respectively; P = 0.022). No significant difference for the augmented tissue thickness was observed among the 4 groups. The augmented tissue thickness measured at 3 mm below the implant shoulder was higher in BBP, XC, and XCP than that in BB (2.43 ± 1.53, 2.62 ± 1.80, and 3.18 ± 1.96 mm versus 0.80 ± 0.90 mm, respectively), trending toward significance (P = 0.052). DBBM2 and a cross-linked CM were significantly more favorable for horizontal bone regeneration compared to DBBM1 and a native CM. However, when DBBM1 and a native CM were secured with fixation pins, outcomes were similar. The addition of pins did not lead to more favorable outcomes when a cross-linked CM was used.

The guided bone regeneration (GBR) technique is an effective treatment for small and medium-sized bone defects in the oral and maxillofacial region. However, currently available collagen membranes have limited functionality and are inadequate for clinical requirements. To address this challenge, this study pioneeringly developed a multifunctional bilayer membrane. Specifically, a bimetallic/polydopamine network (BPN), consisting of silver, magnesium, and dopamine, was successfully synthesized for the first time and integrated with collagen and hydroxyapatite. The resulting material was characterized, and its physicochemical properties, along with its barrier, osteogenic, angiogenic, antibacterial, hemostatic, and biosafety effects, were evaluated through both in vitro and in vivo studies. The results indicated that the BPN, composed of magnesium ions, silver nanoparticles (Ag NPs), and polydopamine (PDA), exhibited excellent thermal stability and slow release of silver and magnesium elements. The BPN/Col-HA membrane featured a bilayer structure with uniform distribution of silver and magnesium. It also demonstrated good hydrophilicity, suitable degradation and mechanical properties, as well as sustained release of silver and magnesium. In vitro experiments showed that the BPN/Col-HA membrane possessed desirable barrier, osteogenic, angiogenic, antibacterial, hemostatic, and biocompatible properties. In vivo results further confirmed its biosafety, hemostatic efficacy, and ability to effectively promote bone defect repair and angiogenesis. Thus, the BPN/Col-HA membrane emerges as a multifunctional GBR membrane with potential for clinical translation.

Several therapeutic approaches have been developed to promote bone regeneration, including guided bone regeneration (GBR), where barrier membranes play a crucial role in segregating soft tissue and facilitating bone growth. This study emphasizes the importance of considering specific tissue requirements in the design of materials for tissue regeneration, with a focus on the development of a double-layered membrane to mimic both soft and hard tissues within the context of GBR. The hard tissue-facing layer comprises collagen and zinc-doped bioactive glass to support bone tissue regeneration, while the soft tissue-facing layer combines collagen and chitosan. The electrospinning technique was employed to achieve the production of nanofibers resembling extracellular matrix fibers. The production of nano-sized (~116 nm) bioactive glasses was achieved by microemulsion assisted sol-gel method. The bioactive glass-containing layers developed hydroxyapatite on their surfaces starting from the first week of simulated body fluid (SBF) immersion, demonstrating that the membranes possessed favorable bioactivity properties. Moreover, all membranes exhibited distinct degradation behaviors in various mediums. However, weight loss exceeding 50% was observed in all tested samples after four weeks in both SBF and phosphate-buffered saline (PBS). The double-layered membranes were also subjected to mechanical testing, revealing a tensile strength of approximately 4 MPa. The double-layered membranes containing zinc-doped bioactive glass demonstrated cell viability of over 70% across all tested concentrations (0.2, 0.1, and 0.02 g/mL), confirming the excellent biocompatibility of the membranes. The fabricated polymer bioactive glass composite double-layered membranes are strong candidates with the potential to be utilized in tissue engineering applications.

Guided bone regeneration (GBR) has become a necessary practice in implantology. Absorbable membranes have shown advantages over non-absorbable membranes, such as blood support of bone tissue. This study aimed to evaluate five collagen membranes in rat calvaria critical-size defects through a histomorphometric analysis of the inflammatory profile during the initial phase of bone repair.

A total of 72 Albinus Wistar rats were used for the study, divided into six groups, with 12 animals per group, and two experimental periods, 7 and 15 days. The groups were as follows: the CG (clot), BG (Bio-Gide®), JS (Jason®), CS (Collprotect®), GD (GemDerm®), and GDF (GemDerm Flex®).

Data showed that the BG group demonstrated an inflammatory profile with an ideal number of inflammatory cells and blood vessels, indicating a statistically significant difference between the JS and CS groups and the BG group in terms of the number of inflammatory cells and a statistically significant difference between the JS and CS groups and the GD group in terms of angiogenesis (p < 0.05).

We conclude that different origins and ways of obtaining them, as well as the thickness of the membrane, can interfere with the biological response of the material.