Mechanisms of guided bone regeneration: a review

Fish scale-derived hydroxyapatite for alveolar ridge preservation

Alveolar ridge resorption following tooth extraction poses significant challenges for future dental restorations. This study investigated the efficacy of fish scale-derived hydroxyapatite (FSHA) as a socket preservation graft material to maintain alveolar bone volume and architecture. FSHA was extracted from *Labeo rohita* fish scales and characterized using Fourier transform infrared (FTIR) analysis. In vitro, biocompatibility and osteogenic potential were assessed using Saos-2 human osteosarcoma cells. Cell viability, migration, and proliferation were evaluated using MTT and scratch assays. In vivo performance was assessed in a rat model, and FSHA was compared to a commercial xenograft (Osseograft) and ungrafted controls. Histological analysis was performed at 8-week post-implantation to quantify new bone formation. FTIR confirmed the purity and homogeneity of FSHA. In vitro, FSHA enhanced Saos-2 viability, migration, and proliferation compared to controls. In vivo, FSHA demonstrated superior bone regeneration compared to Osseograft and ungrafted sites, with balanced graft resorption and new bone formation. Histological analysis revealed an active incorporation of FSHA into new bone, with minimal gaps and ongoing remodeling. Approximately 50%-60% of FSHA was resorbed by 8 weeks, closely matching the rate of new bone deposition. FSHA stimulated more bone formation in the apical socket region than in coronal areas. In conclusion, FSHA is a promising biomaterial for alveolar ridge preservation, exhibiting excellent biocompatibility, osteogenic potential, and balanced resorption. Its ability to promote robust bone regeneration highlights its potential as an effective alternative to currently used graft materials in socket preservation procedures.

A Simplified GBR Treatment and Evaluation of Posterior Seibert Class I Ridge Defects via Bio-collagen and Platelet-Rich Fibrin: A Retrospective Study

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

Microbial colonization in the partially exposed nonabsorbable membrane during alveolar ridge preservation

AIM

This study evaluated the impact of the partial exposition of the nonabsorbable membrane (dPTFE) on microbial colonization during bone healing.

MATERIALS AND METHODS

Patients indicated for tooth extraction were randomized to dPTFE group (n = 22) - tooth extraction and alveolar ridge preservation (ARP) using an intentionally exposed dPTFE membrane and USH group (n = 22) - tooth extraction and unassisted socket healing. Biofilm samples were collected at the barrier in the dPTFE and on the natural healing site in the USH after 3 and 28 days. Samples from the inner surface of the dPTFE barrier were also collected (n = 13). The microbiome was evaluated using the Illumina MiSeq system.

RESULTS

Beta diversity was different from 3 to 28 days in both groups, and at 28 days, different microbial communities were identified between therapies. The dPTFE was characterized by a higher prevalence and abundance of gram-negative and anaerobic species than USH. Furthermore, the inner surface of the dPTFE membrane was colonized by a different community than the one observed on the outer surface.

CONCLUSION

Intentionally exposed dPTFE membrane modulates microbial colonization in the ARP site, creating a more homogeneous and anaerobic community on the inner and outer surfaces of the membrane.

CLINICAL RELEVANCE

DPTFE promoted faster biofilm colonization and enrichment of gram-negative and anaerobes close to the regenerated site in the membrane's inner and outer surfaces. dPTFE membrane can be used exposed to the oral site, but approaches for biofilm control should still be considered. The study was retrospectively registered at Clinicaltrials.gov (NCT04329351).

Double layer graft technique for horizontal alveolar ridge augmentation with staged implant placement: radiographic histological and implant stability analysis-a case report

INTRODUCTION

Horizontal ridge augmentation of a deficient alveolar bone site is performed either simultaneously with implant placement or in a staged approach prior to implant insertion. There are several available strategies for the augmentation of alveolar ridge deficiencies, including guided bone regeneration (GBR) through the use of barrier membranes. The success of the GBR approach mainly depends on the exclusion of soft tissue cells during bone remodeling.

CASE PRESENTATION

A healthy 25-year-old male patient presented with a missing upper left central incisor after clinical and radiographic examination, the site showed a class III defect horizontal atrophy. The procedure performed was the horizontal alveolar ridge augmentation using resorbable pericardium membrane with double layer graft technique (DLT) where autogenous bone placed as a first layer of the graft followed by xenograft as a second layer, the membrane was fixed with titanium pins. A cone beam computed tomography (CBCT) was performed before, immediately and 6 month following the surgery. After 6 months during implant placement, a core biopsy specimen was retrieved, stored and prepared for histological evaluation, with assessment of primary implant stability. The radiographic analysis showed a horizontal width gain of about 4 mm, at 6 month following implant placement, the implant was successfully osteointegrated with stability assessment also done after 6 months from placement.

CONCLUSION

DLT was successfully used for horizontal alveolar ridge augmentation, thus allowing a prosthetically driven implant placement. More cases assessing implant survival and success are needed to confirm the results of this case report.

Engineering a microparticle-loaded rough membrane for guided bone regeneration modulating osteoblast response without inducing inflammation

Guided bone regeneration (GBR) is a widely used procedure that prevents the fast in-growth of soft tissues into bone defect. Among the different types of membranes, the use of collagen membranes is the gold standard. However, these membranes are implanted in tissue location where a severe acute inflammation will occur and can be negatively affected. The aim of this study was to develop a collagen-based membrane for GBR that incorporated alginate-hydroxyapatite microparticles. Membranes were manufactured using collagen type I and gelatin and alginate-hydroxyapatite microparticles. Membranes were assessed in terms of topography by scanning electron microscopy and confocal microscopy; stability by swelling after an overnight incubation in saline and enzymatic degradation against collagenase and mechanical properties by tensile tests. Furthermore, the biological response was assessed with SaOs-2 cells and THP-1 macrophages to determine alkaline phosphatase activity and inflammatory cytokine release. Our results showed that the incorporation of different percentages of these microparticles could induce changes in the surface topography. When the biological response was analyzed, either membranes were not cytotoxic to THP-1 macrophages or to SaOs-2 cells and they did not induce the release of pro-inflammatory cytokines. However, the different surface topographies did not induce changes in the macrophage morphology and the release of pro- and anti-inflammatory cytokines, suggesting that the effect of surface roughness on macrophage behavior could be dependent on other factors such as substrate stiffness and composition. Collagen-gelatin membranes with embedded alginate-hydroxyapatite microparticles increased ALP activity, suggesting a positive effect of them on bone regeneration, remaining unaffected the release of pro- and anti-inflammatory cytokines.

Insights and Advancements in Periodontal Tissue Engineering and Bone Regeneration

The regeneration of periodontal bone defects continues to be an essential therapeutic concern in dental biomaterials. Numerous biomaterials have been utilized in this sector so far. However, the immune response and vascularity in defect regions may be disregarded when evaluating the effectiveness of biomaterials for bone repair. Among several regenerative treatments, the most recent technique of in situ tissue engineering stands out for its ability to replicate endogenous restorative processes by combining scaffold with particular growth factors. Regenerative medicine solutions that combine biomaterials/scaffolds, cells, and bioactive substances have attracted significant interest, particularly for bone repair and regeneration. Dental stem cells (DSCs) share the same progenitor and immunomodulatory properties as other types of MSCs, and because they are easily isolable, they are regarded as desirable therapeutic agents in regenerative dentistry. Recent research has demonstrated that DSCs sown on newly designed synthetic bio-material scaffolds preserve their proliferative capacity while exhibiting increased differentiation and immuno-suppressive capabilities. As researchers discovered how short peptide sequences modify the adhesion and proliferative capacities of scaffolds by activating or inhibiting conventional osteogenic pathways, the scaffolds became more effective at priming MSCs. In this review, the many components of tissue engineering applied to bone engineering will be examined, and the impact of biomaterials on periodontal regeneration and bone cellular biology/molecular genetics will be addressed and updated.

Utilizing partially demineralized dentin plate for horizontal ridge augmentation: A case report

BACKGROUND

This article intends to showcase a case of guided bone regeneration (GBR) utilizing a partially demineralized dentin plate processed from an extracted second molar for horizontal augmentation of the posterior ridge for implant placement.

METHODS AND RESULTS

A 60-year-old patient presented with horizontal ridge deficiency at site #30 and an endodontically treated tooth #31 with recurrent decay. A treatment plan was proposed to extract tooth #31 and utilize a dentin graft from the tooth for ridge augmentation at site #30. Following the atraumatic extraction of tooth #31, it was sectioned into a 1 mm thick dentin plate, sterilized, and processed to obtain a demineralized dentin graft. Following a mid-crestal incision and full-thickness flap elevation, the dentin plate was adapted on the buccal defect of site #30 with 10 mm fixation screws, and the gap between the plate and the buccal bone was filled with 0.5 cc of 50/50 cortico-cancellous bone allograft hydrated with saline, covered with collagen membrane followed by primary closure. At 6 months, a postoperative cone-beam computed tomography (CBCT) was obtained to evaluate the ridge width revealing sufficient ridge width for optimal implant placement. The radio-opaque dentin plate was visible on the CBCT depicting integration with the alveolar ridge. Following surgical implant preparation protocol, a 4 mm diameter and 8.5 mm length implant was placed in a restoratively driven position.

CONCLUSION

This case reports favorable outcomes for GBR using a partially demineralized dentin plate as an alternative to an autogenous bone block graft for horizontal ridge augmentation for future implant placement.

KEY POINTS

This case introduces a novel method utilizing partially demineralized dentin plates derived from extracted teeth for guided bone regeneration, showcasing its potential efficacy in addressing ridge deficiencies. Success, in this case, relies on meticulous sectioning of the tooth and processing of the dentin graft, precise adaptation and fixation of the graft to the residual ridge, and achieving primary closure for undisturbed healing. Limitations to success include the availability of teeth for extraction coinciding with the need for ridge augmentation and unstable graft fixation.

Horizontal GBR with anorganic equine bone combined with a customized titanium mesh

This case report describes the fixed rehabilitation of the lower left arch in a patient following an horizontal GBR procedure by means of a customized titanium mesh and a new slow resorption bone substitute of equine origin.

Morphological Integrated Preparation Method and Implementation of Inorganic/Organic Dual-Phase Composite Gradient Bionic Bone Scaffold

Large bone defects caused by congenital deformities and acquired accidents are increasing day by day. A large number of patients mainly rely on artificial bone for repair. However, artificial bone cannot fully imitate the structure and composition of human bone, resulting in a large gap with autologous bone function. Therefore, this article proposes a continuous preparation method for inorganic/organic biphasic composite gradient biomimetic bulk bone scaffolds. First, a controllable gradient hybrid forming platform for inorganic/organic dual-phase biomaterials was constructed, and the feeding control strategy was studied to achieve precise control of the feeding of sodium alginate/gelatin composite organic materials and hydroxyapatite inorganic materials. The speed is, respectively, sent from the corresponding feeding nozzle to the mixing chamber to realize the uniform mixing of the biphasic material and the extrusion of the composite material, and the inorganic/organic biphasic composite gradient biomimetic bone scaffold with gradual structure and composition is prepared. Second, to prove the superiority of the preparation method, the physicochemical and biological properties of the prepared scaffolds were evaluated. The test results showed that the morphological characteristics of the biphasic composite gradient bone scaffold showed good microscopic porosity and the structure and composition showed gradients. The mechanical properties are close to that of human bone tissue and in vitro cell experiments show that the scaffold has good biocompatibility and bioactivity. In conclusion, this article provides a new type of bone scaffold preparation technology and equipment for the field of tissue engineering, which has research value and application prospects.

Semi-customized three-dimensional ultra-fine titanium meshes in guided bone regeneration for implant therapy in severe alveolar bone defect: a case report

This case report provides a detailed description of a simple and fast bone regeneration procedure using a semi-customized three-dimensional ultra-fine titanium mesh. A 50-year-old male with a severe vertical and horizontal bone defect in the anterior mandible underwent implant treatment in a staged approach. The autologous bone was combined with a xenograft, and the mixture was grafted to augment the bone defect and covered with semi-customized ultra-fine titanium meshes, which were selected among its various types according to size and configuration of the bone defect, directly connected and immobilized on the tenting screws with minimal shaping. In a postoperative 6 months re-entry surgery, the performed titanium meshes were removed, implants were placed, and a bone core biopsy was obtained that demonstrated satisfactory new bone formation. Finally, two months later, the definitive prosthesis was installed. This semi-customized ultra-fine titanium mesh could help an implant clinician obtain more predictable results in the guided bone regeneration (GBR).

A Novel Approach for the Treatment of Recurrent Oroantral Fistula Occurring at an Infected Sinus Augmentation Site

Closing a recurrent oroantral fistula (OAF) that occurs at an infected sinus augmentation site is a challenge for clinicians. The recurrent OAF has a detrimental impact on bone regeneration and subsequent implant placement. This case report includes three cases in which sinus graft infection and OAF occurred after maxillary sinus augmentation (MSA). In these cases, treatments to control sinus infection were performed using an otolaryngologist; then, intraoral interventions comprising mucosal flap procedures, bone grafts, and barrier membrane applications were performed 2-5 times by oral surgeons. Nevertheless, OAF recurred persistently. The failure to stop OAF recurrence may be due to the inability to effectively block air pressure at the OAF site. Following a comprehensive debridement of the infected tissue at the previous sinus augmentation site, a pouch was created through sinus mucosal elevation. The perforated sinus mucosa at the OAF site was covered with a non-resorbable membrane in one case and with resorbable collagen membranes in the other two cases, followed by bone grafting within the pouch. Lastly, this procedure was completed by blocking the entrance of the pouch with a cortical bone shell graft and a resorbable collagen membrane. The cortical bone shell graft, obstructing the air pressure from the nasal cavity, facilitated bone formation, and, ultimately, allowed for implant placement. Within the limitations of the present case report, the application of a guided bone regeneration technique involving a cortical bone shell graft and a barrier membrane enabled the closure of the recurrent OAF and subsequent implant placement.

A systematic review of oral wound healing indices

Wound healing monitoring for abnormality identification and intervention is crucial to securing a successful surgical outcome. Indices have been used to summarize the degree of healing. Given the increasing frequency of regenerative procedures which preserve dentition and implant stability, and the higher esthetic demands, an appraisal of the available indices is needed to identify the current knowledge gap. This study aimed to systematically review published oral wound healing indices and scores.

MATERIALS AND METHODS

A complete literature electronic search in 5 databases was conducted by two reviewers. A combination of keywords related to oral wound healing was used.

RESULTS

A total of 11 articles were included in the evaluation of various procedures (conventional periodontal procedures, guided tissue regeneration, soft tissue reconstruction procedures, and tooth extractions), at different time points (1 day to 12 weeks), with a focus on diverse clinical signs and symptoms. Frequently evaluated parameters included wound dehiscence/epithelialization (91%), tissue color (redness) (73%), suppuration (55%), swelling/edema (55%), and hemostasis (55%). Other less commonly used parameters include esthetics-related and patient-centered outcomes.

CONCLUSION

The available indices evaluate a diverse group of subjective clinical signs and symptoms to estimate the underlying biological healing events and assess the degree of clinical success. The majority of the included indices are not validated. Quantitative and objective subclinical parameters including blood perfusion, biomaterial stability, and completeness of epithelialization, are needed for customized wound healing care and better outcome prediction.

Clinical and Radiographic Outcomes of Autogenous Inlay Graft vs Autogenous Onlay Graft for Anterior Maxillary Horizontal Ridge Augmentation: A Randomized Control Clinical Study

AIM

This study aimed to compare the efficacy of autogenous onlay and inlay grafts for anterior maxillary horizontal ridge augmentation.

MATERIALS AND METHODS

This randomized clinical trial was performed on 14 patients with a deficient partially edentulous anterior maxillary ridge (3-5 mm in width). Patients were randomized and grouped into two equal groups: Group A was treated with symphyseal autogenous bone block, which was placed and fixed buccally as an onlay graft, and group B: was treated with symphyseal autogenous bone block, which was interpositioned and fixed in space created between buccal and lingual cortex as inlay graft. Patients were evaluated clinically and radiographically to evaluate the increase of bone width at [Baseline, immediate postoperative (T0)] and six months post-graft (T6).

RESULTS

A total of 14 patients (8 males and 6 females) with age range from 20 to 43 years old with a mean of 42.1 years were involved in our study. Radiographically, there was a significant statistical difference in comparing between two groups for the creation of a horizontal alveolar bone at T0. In the inlay group, the mean preoperative bone width was 3.9 ± 0.3 mm at T0 and 5.7 ± 0.5 mm at T6. While in the onlay group, the mean preoperative bone width was 3.7 ± 0.7 mm at T0 while at T6 the mean bone width was 6.1 ± 0.8 mm. This was statistically significant.

CONCLUSION

Inlay block graft appears to be a successful treatment option for horizontal ridge augmentation in the maxillary arch.

CLINICAL SIGNIFICANCE

both techniques are viable techniques for augmentation of atrophic alveolar ridge with uneventful healing. How to cite this article: Elsayed AO, Abdel-Rahman FH, Ahmed WMAS, et al. Clinical and Radiographic Outcomes of Autogenous Inlay Graft vs Autogenous Onlay Graft for Anterior Maxillary Horizontal Ridge Augmentation: A Randomized Control Clinical Study. J Contemp Dent Pract 2024;25(2):107-113.

Horizontal ridge augmentation with particulate cortico-cancellous freeze-dried bone allograft alone or combined with injectable-platelet rich fibrin in a randomized clinical trial

OBJECTIVES

The objective of this study is to assess the effectiveness of horizontal ridge augmentation using FDBA in combination with injectable-platelet rich fibrin (i-PRF) versus FDBA alone. To fulfill this aim, the radiographic and histomorphometric outcomes are compared.

METHOD

The study involved 41 patients who had horizontal alveolar ridge defects categorized as either B (2.5-7 mm) or C (0-2.5 mm). The control group received FDBA alone (n = 20), while the test group received FDBA in combination with i-PRF (n = 21). The horizontal dimensions of the alveolar ridge were measured at 0, 2, 4, and 6 mm from the bone crest using CBCT before and 6 months after alveolar ridge augmentation. In the second-stage surgery, 24 biopsies were taken from the augmented bone - 13 from the control group and 11 from the test group, and were examined histologically and histomorphometrically. The data were analyzed using Pearson correlation coefficient, chi-square, paired-t, and two-sample t tests.

RESULTS

There was no significant difference (p > 0.05) in the increase of mean ridge width between the test group and the control group after 6 months at distances of 0, 2, 4, and 6 mm from the crest, with differences of -0.28, 0.12, 0.52, and 1.04 mm, respectively. However, the amount of newly formed bone and material residues was significantly higher in the FDBA + i-PRF group compared to the FDBA alone group (45.01% and 13.06% vs 54.03% and 8.48%, respectively). There was no significant difference in the amount of soft tissue between the two groups (41.02% and 37.5%, p > 0.05).

CONCLUSION

The study found that there was no statistically significant difference in the increase of horizontal ridge width between the FDBA + i-PRF group and the FDBA group. However, the histomorphometric analysis revealed that the FDBA + i-PRF group had a higher proportion of newly formed bone, less connective tissue, and fewer residual particles. This suggests a superior quality of bone formation compared to the FDBA group.

Evaluation of the Success of Autogenous Block Grafting in Atrophic Maxillary and Mandibular Ridges Prior to and After Implant Placement

BACKGROUND

Dental implantology's success relies on adequate bone volume and quality, necessitating bone augmentation for implant placement. Primary lateral bone augmentation, utilizing autogenous block grafts, addresses horizontal bone loss.

OBJECTIVE

This study aims to evaluate the efficacy of autogenous block grafting, specifically ramus and fibula blocks, in addressing severe atrophic ridges before and after implant placement.

METHODS

Twenty-one patients underwent block grafting, predominantly using the ramus technique (80/20 ratio). CBCT measurements assessed horizontal grafting outcomes. Implant success and bone volume changes were analyzed.

RESULTS

Post-grafting, bone width increased from 1.8-3.1 mm to 4.5-6 mm, exceeding critical thresholds. Implant success reached 95%, indicating the grafting techniques' effectiveness.

CONCLUSION

Autogenous block grafting, especially with ramus and fibula blocks, transforms severe atrophic ridges, enabling successful implant integration. Long-term follow-up is essential for a comprehensive evaluation.

CLINICAL RELEVANCE

This study provides crucial insights into autogenous block grafting's transformative impact on challenging cases, guiding future applications in reconstructive dentistry.

Platelet-rich fibrin for rehydration and pre-vascularization of an acellular, collagen membrane of porcine origin

OBJECTIVES

Pre-vascularization of the collagen membranes with autologous platelet concentrates is a standard procedure in oral and maxillofacial surgery. This study analyzed the possible interaction of an acellular collagen membrane of porcine origin (NM) with platelet-rich fibrin (PRF) regarding its rehydration protocol with differences in pH values and effect on angiogenesis.

MATERIALS AND METHODS

NM was analyzed alone and combined with solid PRF by plotting or co-culturing with injectable PRF. Different media (venous blood, buffer solution with a fixed pH value of 7, saline solution, and injectable PRF) were used to analyze the influence on pH value during rehydration. Chorion allantois membrane assay (CAM) was applied to check pro-angiogenic effects after 24, 48, and 72 h, followed by immunohistochemical analysis.

RESULTS

Rehydration in injectable PRF showed acidity over time (p < 0.05). A definite pro-angiogenic effect of NM alone was found regarding neo-vessel formation supported by the respective light microscopically analysis without significant differences to PRF alone (p > 0.005). This pro-angiogenic effect could not be exaggerated when NM was combined with liquid/solid PRF (each p > 0.005).

CONCLUSIONS

Rehydration with liquid PRF of the collagen membrane results in acidity compared to a saline solution or patient's blood. The significant pro-angiogenic potential of the membrane alone resulted in enhanced neo-vessel formation that could not be optimized with the addition of PRF.

CLINICAL RELEVANCE STATEMENT

Using injectable PRF for rehydration protocol of the collagen membrane leads to acidosis that can ultimately optimize wound healing. Differences in the physio-mechanical interplay of collagen matrices and autologous platelet concentrates must result in clinical algorithms if pre-vascularization can maximize outcomes.

Dual Mg-Reinforced PCL Membrane with a Janus Structure for Vascularized Bone Regeneration and Bacterial Elimination

Commercially available guided bone regeneration (GBR) membranes often exhibit limited mechanical properties or bioactivity, leading to poor performance in repairing bone defects. To surmount this limitation, we developed a Janus structural composite membrane (Mg-MgO/PCL) reinforced by dual Mg (Mg sheets and MgO NPs) by using a combined processing technique involving casting and electrospinning. Results showed that the addition of Mg sheets and MgO NPs enhanced the mechanical properties of the composite membrane for osteogenic space maintenance, specifically tensile strength (from 10.2 ± 1.2 to 50.3 ± 4.5 MPa) and compression force (from 0 to 0.94 ± 0.09 N mm-1), through Mg sheet reinforcement and improved crystallization. The dense cast side of the Janus structure membrane displayed better fibroblast barrier capacity than a single fiber structure; meanwhile, the PCL matrix protected the Mg sheet from severe corrosion due to predeformation. The porous microfibers side supported preosteoblast cell adhesion, enhanced osteogenesis, and angiogenesis in vitro, through the biomimetic extracellular matrix and sustainable Mg2+ release. Furthermore, the Mg-MgO/PCL membrane incorporating 2 wt % MgO NPs exhibited remarkable antimicrobial properties, inducing over 88.75% apoptosis in Staphylococcus aureus. An in vivo experiment using the rat skull defect model (Φ = 5 mm) confirmed that the Mg-MgO/PCL membrane significantly improved new bone formation postsurgery. Collectively, our investigation provides valuable insights into the design of multifunctional membranes for clinical oral GBR application.

Poly(lactic acid/caprolactone) bilayer membrane achieves bone regeneration through a prolonged barrier function

Guided bone regeneration (GBR) is a treatment strategy used to recover bone volume. Barrier membranes are a key component of GBR protocols, and their properties can impact treatment outcomes. This study investigated the efficacy of an experimental, slow-degrading, bilayer barrier membrane for application in GBR using in vivo animal models. A synthetic copolymer of poly(lactic acid/caprolactone) (PLCL) was used to prepare a slow-degrading bilayer membrane. The biodegradability of PLCL was evaluated by subcutaneous implantation in a rat model. The barrier function of the PLCL membrane was investigated in a rat calvaria defect model and compared with commercially available membranes composed of type I collagen (Col) and poly(lactic-co-glycolic acid) (PLGA). An alveolar bone defect model in beagle dogs was used to simulate GBR protocols to evaluate the bone regeneration ability of the experimental PLCL membrane. The PLCL membrane showed slow biodegradation, resulting in an efficient and prolonged barrier function compared with commercial materials. In turn, this barrier function enabled the space-making ability of PLCL membrane and facilitated bone regeneration. In the alveolar bone defect model, significantly greater regeneration was achieved by treatment with PLCL membrane compared with Col and PLGA membranes. Additionally, a continuous alveolar ridge contour was observed in PLCL-treated bone defects. In conclusion, the PLCL bilayer membrane is a promising biomaterial for use in GBR given its slow degradation and prolonged barrier function.

Atypical histological presentation of bone regeneration after insertion of cryoprotected allogeneic bone graft

BACKGROUND

To evaluate bone regenerative capacity of cryoprotected corticocancellous allogeneic bone graft performed in type II and III post-extraction sockets for ridge preservation after twelve weeks in-vivo.

MATERIAL AND METHODS

Twenty-seven type II or III bony-walled extraction sockets (mandible and maxilla) were selected for this study. Following atraumatic tooth-extraction a cryoprotected corticocancellous allogeneic bone graft material and a resorbable porcine-derived collagen membrane were used for ridge preservation. During re-entry surgery at approximately 12 weeks, bone core biopsies were obtained using a 3.2 mm trephine drill and samples were histologically processed and subjected to qualitative and quantitative histomorphometric analysis. Quantitative data was analyzed using a general linear mixed model with results presented as mean values with the corresponding 95% confidence interval values.

RESULTS

Healing without incident and ridge preservation allowed for the placement of dental implants after 12 weeks in 25 out of the 27 treated socket sites. Analyses yielded an average of ~21.0±7% of old/native bone, ~17±5.5% of newly regenerated bone (total of ~38±12.8% for all bone), 0.23±0.14% of new bone presenting with nucleating sites within the matrix, ~52±5.12% of soft tissue, and 3.6±2.09% of damaged bone. The average regenerated bone was statistically analogous to that of old/native bone (p=0.355). Furthermore, an atypical histological pattern of bone regeneration was observed, with newly formed bone exhibiting "infiltration-like" behavior and with new bone nucleating sites observed within the demineralized bone matrix.

CONCLUSIONS

Cryoprotected corticocancellous allogeneic bone-graft demonstrated osteoconductive, osteoinductive, and osteogenic properties, yielding unique healing patterns which does warrant further investigation.

Appraising and comparing the role of autogenous periosteal graft as a barrier membrane in the treatment of intrabony defects in chronic periodontitis cases: A systematic review and meta-analysis

Periodontal regeneration refers to procedures aimed at restitution of lost supporting tissue around the periodontally compromised tooth. Regenerative procedures very often include the use of barrier materials to encourage the growth of key surrounding tissues. The current study aimed to evaluate the effectiveness of autogenous periosteal graft as a barrier membrane for the treatment of intrabony defects in chronic periodontitis patients. A total of four data bases MEDLINE (by PubMed), Cochrane database, EBSCO, and Google Scholar were explored to identify the studies in English up to December 2022. An additional hand search of relevant journals was also done. A team of three independent reviewers screened the retrieved articles using the inclusion criteria. Randomized control trials (RCTs) evaluating the effectiveness of autogenous periosteal grafts in the treatment of intrabony defects in chronic periodontitis cases were included in the study. A total of six relevant articles were recognized for data procurement. A total of 117 patients with 68 sites with an age range between 18 years and 55 years were selected. Outcome variables examined were pocket depth (PD), clinical attachment level (CAL), radiographic bone defect fill (BDF), gingival recession (GR), plaque index (PI), gingival index (GI) and bleeding on probing (BOP). Data were analyzed using Revman 5.3 software. The mean differences and 95% confidence interval were used to illustrate the estimate of effect size. There is an equal effect in both groups for the PI, GI, and BOP reduction. For PD reduction, the result was in the favor of periosteal graft with open flap debridement (OFD) group. For CAL gain, radiographic BDF and GR, results also favored the periosteal graft, but no statistically significant difference was found amongst the groups. Within the limitation of the study, it seems that the autogenous periosteal graft can be used successfully along with OFD to treat intrabony defects in chronic periodontitis patients.

Attachment and proliferation of human gingival fibroblasts seeded on barrier membranes using Wharton's jelly-derived stem cells conditioned medium: An in vitro study

The effect of Wharton's jelly mesenchymal stem cells conditioned medium (WJMSCs-CM) and zinc oxide nanoparticles (ZnO-NPs) on cultured human gingival fibroblasts on various barrier membranes was investigated in this study. In this study, human gingival fibroblasts were prepared and cultured on three membranes: collagen membrane, acellular dermal matrix (ADM) with ZnO-NPs, and ADM without ZnO-NPs. WJMSCs-CM was given to the testing groups, while control groups received the same membranes without WJMSCs-CM. Following 48 and 72 h, 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) tests were performed to assess cell survival. Cell proliferation on the membranes was also evaluated using 4',6-diamidino-2-phenylindole (DAPI) staining after 48 and 72 h. Field emission scanning electron microscopy was used to determine membrane surface structure and cell adhesion. Nanoparticles were also subjected to an energy-dispersive x-ray analysis to identify their chemical structure. Two-way analysis of variance was used to conduct the statistical analysis. The p-value ≤.05 was considered significant. When ADM-ZnO-NPs were combined with CM, fibroblast viability, and adhesion significantly differed from ADM-ZnO-NPs alone. DAPI results confirmed cell proliferation in all six groups on both experiment days. The abundance and concentrated distribution of cells during cell proliferation were found in CM-containing membranes, specifically the ADM-ZnO-NPs membrane, demonstrating the improved biocompatibility of the ADM-ZnO-NPs membrane for cell proliferation. The other groups did not significantly differ from one another. WJMSCs-CM positively affected the viability and proliferation of gingival fibroblasts, but only marginally. Under certain conditions, ZnO-NPs below a specific concentration increased the biocompatibility of the membranes.

Regeneration Membranes Loaded with Non-Antibiotic Anti-2 Microbials: A Review

Both guided bone and guided tissue regeneration are techniques that require the use of barrier membranes. Contamination and infection of the surgical area is one of the most feared complications. Some current lines of research focus on functionalizing these membranes with different antimicrobial agents. The objective of this study was to carry out a review of the use and antibacterial properties of regeneration membranes doped with antimicrobials such as zinc, silver, chlorhexidine, and lauric acid. The protocol was based on PRISMA recommendations, addressing the PICO question: "Do membranes doped with non-antibiotic antimicrobials have antibacterial activity that can reduce or improve infection compared to membranes not impregnated with said antimicrobial?" Methodological quality was evaluated using the RoBDEMAT tool. A total of 329 articles were found, of which 25 met the eligibility criteria and were included in this review. Most studies agree that zinc inhibits bacterial growth as it decreases colony-forming units, depending on the concentration used and the bacterial species studied. Silver compounds also decreased the secretion of proinflammatory cytokines and presented less bacterial adhesion to the membrane. Some concentrations of chlorhexidine that possess antimicrobial activity have shown high toxicity. Finally, lauric acid shows inhibition of bacterial growth measured by the disk diffusion test, the inhibition zone being larger with higher concentrations. Antimicrobial agents such as zinc, silver, chlorhexidine, and lauric acid have effective antibacterial activity and can be used to dope regenerative membranes in order to reduce the risk of bacterial colonization.

Guided Bone Regeneration Using Barrier Membrane in Dental Applications

Guided bone regeneration (GBR) is a widely used technique in preclinical and clinical studies due to its predictability. Its main purpose is to prevent the migration of soft tissue into the osseous wound space, while allowing osseous cells to migrate to the site. GBR is classified into two main categories: resorbable and non-resorbable membranes. Resorbable membranes do not require a second surgery but tend to have a short resorption period. Conversely, non-resorbable membranes maintain their mechanical strength and prevent collapse. However, they require removal and are susceptible to membrane exposure. GBR is often used with bone substitute graft materials to fill the defect space and protect the bone graft. The membrane can also undergo various modifications, such as surface modification and biological factor loading, to improve barrier functions and bone regeneration. In addition, bone regeneration is largely related to osteoimmunology, a new field that focuses on the interactions between bone and the immune system. Understanding these interactions can help in developing new treatments for bone diseases and injuries. Overall, GBR has the potential to be a powerful tool in promoting bone regeneration. Further research in this area could lead to advancements in the field of bone healing. This review will highlight resorbable and non-resorbable membranes with cellular responses during bone regeneration, provide insights into immunological response during bone remodeling, and discuss antibacterial features.

Membrane barriers for guided bone regeneration: An overview of available biomaterials

Dental implants revolutionized the treatment options for restoring form, function, and esthetics when one or more teeth are missing. At sites of insufficient bone, guided bone regeneration (GBR) is performed either prior to or in conjunction with implant placement to achieve a three-dimensional prosthetic-driven implant position. To date, GBR is well documented, widely used, and constitutes a predictable and successful approach for lateral and vertical bone augmentation of atrophic ridges. Evidence suggests that the use of barrier membranes maintains the major biological principles of GBR. Since the material used to construct barrier membranes ultimately dictates its characteristics and its ability to maintain the biological principles of GBR, several materials have been used over time. This review, summarizes the evolution of barrier membranes, focusing on the characteristics, advantages, and disadvantages of available occlusive barrier membranes and presents results of updated meta-analyses focusing on the effects of these membranes on the overall outcome.

Accumulative Rolling Mg/PLLA Composite Membrane with Lamellar Heterostructure for Enhanced Bacteria Inhibition and Rapid Bone Regeneration

Developing composite materials with optimized mechanics, degradation, and bioactivity for bone regeneration has long been a crucial mission. Herein, a multifunctional Mg/Poly-l-lactic acid (Mg/PLLA) composite membrane based on the "materials plain" concept through the accumulative rolling (AR) method is proposed. Results show that at a rolling ratio of 75%, the comprehensive mechanical properties of the membrane in the rolling direction are self-reinforced significantly (elongation at break ≈53.2%, tensile strength ≈104.0 MPa, Young's modulus ≈2.13 GPa). This enhancement is attributed to the directional arrangement and increased crystallization of PLLA molecular chains, as demonstrated by SAXS and DSC results. Furthermore, the AR composite membrane presents a lamellar heterostructure, which not only avoids the accumulation of Mg microparticles (MgMPs) but also regulates the degradation rate. Through the contribution of bioactive MgMPs and their photothermal effect synergistically, the membrane effectively eliminates bacterial infection and accelerates vascularized bone regeneration both in vitro and in vivo. Notably, the membrane exhibits outstanding rat skull bone regeneration performance in only 4 weeks, surpassing most literature reports. In short, this work develops a composite membrane with a "one stone, four birds" effect, opening an efficient avenue toward high-performance orthopedic materials.

Evaluation of the biological effects of amelogenin on human oral keratinocytes

OBJECTIVES

Amelogenins are clinically used in periodontal regeneration as main components of root surface modifying agents, even without specifically preventing the premature colonization of the healing tissue defect by means of a physical barrier membrane. The objective of this study was to investigate the effects of human amelogenin on the proliferation, migration, and morphology of Immortalized Human Oral Keratinocytes (iHOKs).

METHODS

Immortalized Human Oral Keratinocytes were expanded in Keratinocyte Growth Medium-2 (KGM-2). Full-length recombinant amelogenin protein was diluted in KGM-2 in five concentrations (10 ng/ml, 100 ng/ml, 1.000 ng/ml, 5.000 ng/ml and 10.000 ng/ml). iHOKs were cultured in medium supplemented with the amelogenin dilutions. Samples without amelogenin served as control. Cell metabolism and cell proliferation together with cell migration were evaluated at day 7, 14, 21.

RESULTS

At day 7, iHOKs treated with 10,000 ng/ml showed a significant decrease in keratinocytes´ proliferation. The metabolic activity at this timepoint was significantly lower for concentrations ≥ 1000 ng/ml. At days 14 and 21, both the addition of 5000 ng/ml and even more 10,000 ng/ml amelogenin reduced significantly the proliferation of keratinocytes. The effects on the metabolic activity for these timepoints were visible already with 100 ng/ml. Treatment of iHOKs with amelogenin of ≥ 1000 ng/ml led to inhibitory effects on cell migration already after 24 h.

CONCLUSIONS

The full-length recombinant amelogenin has a significant biological impact on iHOKs. The increasing dose dependent inhibitory effects of amelogenin shown on iHOKs might explain the disruption of the apical migration of the junctional epithelium during regenerative healing.

CLINICAL SIGNIFICANCE

Amelogenin, presents time- and dose-dependent inhibitory effects on the growth of keratinocytes, which might explain the biological rationale behind its application in periodontal regeneration.

Regeneration of Buccal Wall Defects after Tooth Extraction with Biphasic Calcium Phosphate in Injectable Form vs. Bovine Xenograft: A Randomized Controlled Clinical Trial

Bone healing after tooth extraction may be affected by defects of the alveolus buccal wall, such as fenestrations and dehiscences. Therefore, to minimize dimensional changes it is advisable to perform alveolar ridge preservation after tooth extractions. Different biomaterials are used for this purpose. The aim of this study was to investigate the qualitative and quantitative histological changes in human biopsies taken after 6 months of healing of extraction sockets with buccal wall defects. For this purpose, the defects of 36 patients (18 per group) were treated with injectable biphasic calcium phosphate (I-BCP) or bovine xenograft (BX) after extraction. After six months of healing, biopsies were taken and proceeded to the histology laboratory. No evidence of an inflammatory response of the tissue was observed in the biopsies of either group, and the newly formed bone (NB) was in close contact with the remaining biomaterial (BM). The histomorphometric results showed that there was no statistically significant difference between the groups in the mean percentage of NB (p = 0.854), BM (p = 0.129), and soft tissue (p = 0.094). To conclude, both biomaterials exhibited osteoconductivity and biocompatibility and achieved satisfactory bone regeneration of buccal wall defects after tooth extraction.

Guided Tissue and Bone Regeneration Membranes: A Review of Biomaterials and Techniques for Periodontal Treatments

This comprehensive review provides an in-depth analysis of the use of biomaterials in the processes of guided tissue and bone regeneration, and their indispensable role in dental therapeutic interventions. These interventions serve the critical function of restoring both structural integrity and functionality to the dentition that has been lost or damaged. The basis for this review is laid through the exploration of various relevant scientific databases such as Scopus, PubMed, Web of science and MEDLINE. From a meticulous selection, relevant literature was chosen. This review commences by examining the different types of membranes used in guided bone regeneration procedures and the spectrum of biomaterials employed in these operations. It then explores the manufacturing technologies for the scaffold, delving into their significant impact on tissue and bone regenerations. At the core of this review is the method of guided bone regeneration, which is a crucial technique for counteracting bone loss induced by tooth extraction or periodontal disease. The discussion advances by underscoring the latest innovations and strategies in the field of tissue regeneration. One key observation is the critical role that membranes play in guided reconstruction; they serve as a barrier, preventing the entry of non-ossifying cells, thereby promoting the successful growth and regeneration of bone and tissue. By reviewing the existing literature on biomaterials, membranes, and scaffold manufacturing technologies, this paper illustrates the vast potential for innovation and growth within the field of dental therapeutic interventions, particularly in guided tissue and bone regeneration.

A Bibliometric Study on the Top 101 Most-Cited Articles of Dental Journals of the Middle East/North Africa Countries From 2011 to 2021

Introduction: This retrospective descriptive study evaluated the Scopus-indexed dental journals and their most-cited documents affiliated with the Middle East and North Africa (MENA) countries from 2011 to 2021. Methods: Dental journals affiliated with MENA countries, their bibliometric indicators (SJR, CiteScore, SNIP, and H-index), and the 101 most cited articles of the considered journals were extracted and studied through descriptive statistics. In addition, the "citation per year" of each top 101 articles was calculated. Spearman's rho test was used for pairwise comparisons of the correlation coefficient values between each two of the considered bibliometric indicators. Results: The number of citations of the 101 most-cited papers ranged from 35 to 203. The mean (SD) citations of studied articles were 61.33 (37.58) and the median was 46. Furthermore, CiteScore had the highest significant correlation with SJR (r=0.828, P˂0.001). Moreover, the citation per year of the top 101 documents had no significant relationship with any of the journals' bibliometric indicators. Conclusion: Because journal performance and citation rate are multi-dimensional concepts, a single metric cannot express them thoroughly despite correlations between indices. "European Journal of Dentistry" from Turkey, "Saudi Dental Journal" from Saudi Arabia, and "Iranian Endodontic Journal" and "Journal of Lasers in Medical Sciences" both from Iran had the highest ranks in the SCImago portal and the highest scores in bibliometric indices amongst the MENA dental journals.

Resorbable membrane design: In vitro characterization of silver doped-hydroxyapatite-reinforced XG/PEI semi-IPN composite

In this study, the production and characterization of silver-doped hydroxyapatite (AgHA) reinforced Xanthan gum (XG) and Polyethyleneimine (PEI) reinforced semi-interpenetrating polymer network (IPN) biocomposite, known to be used as bone cover material for therapeutic purposes in bone tissue, were performed. XG/PEI IPN films containing 2AgHA nanoparticles were produced by simultaneous condensation and ionic gelation. Characteristics of 2AgHA-XG/PEI nanocomposite film were evaluated by structural, morphological (SEM, XRD, FT-IR, TGA, TM, and Raman) and biological activity analysis (degradation, MTT, genotoxicity, and antimicrobial activity) techniques. In the physicochemical characterization, it was determined that 2AgHA nanoparticles were homogeneously dispersed in the XG/PEI-IPN membrane at high concentration and the thermal and mechanical stability of the formed film were high. The nanocomposites showed high antibacterial activity against Acinetobacter Baumannii (A.Baumannii), Staphylococcus aureus (S.aureus), and Streptococcus mutans (S.mutans). L929 exhibited good biocompatibility for fibroblast cells and was determined to support the formation of MCC cells. It was shown that a resorbable 2AgHA-XG/PEI composite material was obtained with a high degradation rate and 64% loss of mass at the end of the 7th day. Physico-chemically developed biocompatible and biodegradable XG-2AgHA/PEI nanocomposite semi-IPN films possessed an important potential for the treatment of defects in bone tissue as an easily applicable bone cover. Besides, it was noted that 2AgHA-XG/PEI biocomposite could increase cell viability, especially in dental-bone treatments for coating, filling, and occlusion.

Underestimated microbial infection of resorbable membranes on guided regeneration

Barrier membranes are critical in creating tissuecompartmentalization for guided tissue (GTR) and bone regeneration (GBR) therapies. More recently, resorbable membranes have been widely used for tissue and bone regeneration due to their improved properties and the dispensable re-entry surgery for membrane removal. However, in cases with membrane exposure, this may lead to microbial contamination that will compromise the integrity of the membrane, surrounding tissue, and bone regeneration, resulting in treatment failure. Although the microbial infection can negatively influence the clinical outcomes of regenerative therapy, such as GBR and GTR, there is a lack of clinical investigations in this field, especially concerning the microbial colonization of different types of membranes. Importantly, a deeper understanding of the mechanisms of biofilm growth and composition and pathogenesis on exposed membranes is still missing, explaining the mechanisms by which bone regeneration is reduced during membrane exposure. This scoping review comprehensively screened and discussed the current in vivo evidence and possible new perspectives on the microbial contamination of resorbable membranes. Results from eligible in vivo studies suggested that different bacterial species colonized exposed membranes according to their composition (collagen, expanded polytetrafluoroethylene (non-resorbable), and polylactic acid), but in all cases, it negatively affected the attachment level and amount of bone gain. However, limited models and techniques have evaluated the newly developed materials, and evidence is scarce. Finally, new approaches to enhance the antimicrobial effect should consider changing the membrane surface or incorporating long-term released antimicrobials in an effort to achieve better clinical success.

Evaluation of bone gain in horizontal ridge augmentation using titanium mesh in combination with different flap advancement techniques: a randomized clinical trial

The aim of this study was to investigate and compare the clinical and radiographic bone gain in guided bone regeneration with titanium mesh, for four different advancement techniques: periosteal releasing incision (PRI), double flap incision (DFI), modified periosteal releasing incision (MPRI), and coronally advanced lingual flap (CALF). Forty patients with a partially edentulous mandible were allocated randomly to four study groups (PRI, DFI, MPRI, CALF; 10 patients in each). Clinical bone gain (primary outcome) and radiographic bone gain were evaluated. In addition, correlations between study variables (clinical and radiographic bone gain, flap advancement, mesh exposure area and percentage exposure, pain, and swelling) were explored. CALF exhibited the highest mean clinical bone gain (4.12 ± 1.37 mm) and PRI the lowest (2.60 ± 1.36 mm); the mean clinical bone gain differed significantly among the groups (P < 0.001). The highest mean radiographic bone gain was seen in the CALF group (3.54 ± 1.65 mm) and the lowest in the PRI group (2.06 ± 1.11 mm); the mean radiographic bone gain also differed significantly among the groups (P < 0.001). The correlation analysis revealed positive correlations between flap advancement and radiographic bone gain (P = 0.003) and between swelling and pain (P = 0.007). An inverse correlation was found between flap advancement and swelling (P = 0.049), mesh exposure area and clinical bone gain (P = 0.022), and mesh exposure percentage and clinical bone gain (P = 0.017). In summary, the highest clinical and radiographic bone gain was observed for CALF, while the lowest was observed for PRI.

Evaluation of efficacy of non-resorbable membranes compared to resorbable membranes in patients undergoing guided bone regeneration

Background

Replacement of missing teeth in patients with prolonged edentulism poses a challenge for clinicians. An extended period of edentulism results in severe atrophy of alveolar ridges rendering them unsatisfactory for rehabilitation using an implant-supported prosthesis. To overcome this difficulty, Guided Bone Regeneration (GBR) was introduced and constructed upon the principles of Guided Tissue Regeneration (GTR) procedures. Evidence suggests that GBR has proven to be a predictable treatment modality for treating vertical and horizontal ridge deficiencies.

Objective

The present systematic review aimed to evaluate the efficacy of non-resorbable (N-RES) membranes compared to resorbable (RES) membranes in patients undergoing GBR.

Methods

An electronic search of three databases, including PubMed, Web of Science, and Scopus, was conducted for articles published until March 2022. A supplementary manual search of references from these articles was performed to include any articles that may have been overlooked in the electronic search. Articles that evaluated the efficacy of RES membranes and N-RES membranes in GBR were included. Case reports, case series, commentaries, letters to the editor, narrative or systematic reviews were excluded. Articles in languages other than English were also excluded. The articles were assessed against risk of bias 2 tool for Randomized Control Trials (RCTs) and ROBINS-I tool for Non-Randomized Clinical Trials (N-RCTs). The Grading of Recommendations Assessment, Development and Evaluation (GRADE) assessment was followed based on the Cochrane Handbook for quality assessment. A summary of findings table was used to present the results.

Results

One hundred and fifty one articles were identified in an electronic search. Eight articles met the inclusion criteria and were included in the present systematic review. The studies were conducted on partially or completely edentulous patients with alveolar ridge deficiencies undergoing vertical or horizontal bone for subsequent implant placement. The majority of the studies reported similar results for bone gain in both RES and N-RES membrane groups.

Conclusion

The available evidence suggests that RES and N-RES membranes are equally effective in GBR. However, the evidence must be interpreted with caution due to its 'low quality' GRADE assessment.

Clinical implications

Further research focusing on human clinical trials with well-matched subjects with homogeneity in the type and method of GBR and method of assessment of new bone formation will derive conclusive results on the efficacy of RES and N-RES membranes in achieving new bone formation.

Unique Fiber Morphologies from Emulsion Electrospinning—A Case Study of Poly(ε-caprolactone) and Its Applications

The importance of electrospinning to produce biomimicking micro- and nano-fibrous matrices is realized by many who work in the area of fibers. Based on the solubility of the materials to be spun, organic solvents are typically utilized. The toxicity of the utilized organic solvent could be extremely important for various applications, including tissue engineering, biomedical, agricultural, etc. In addition, the high viscosities of such polymer solutions limit the use of high polymer concentrations and lower down productivity along with the limitations of obtaining desired fiber morphology. This emphasizes the need for a method that would allay worries about safety, toxicity, and environmental issues along with the limitations of using concentrated polymer solutions. To mitigate these issues, the use of emulsions as precursors for electrospinning has recently gained significant attention. Presence of dispersed and continuous phase in emulsion provides an easy route to incorporate sensitive bioactive functional moieties within the core-sheath fibers which otherwise could only be hardly achieved using cumbersome coaxial electrospinning process in solution or melt based approaches. This review presents a detailed understanding of emulsion behavior during electrospinning along with the role of various constituents and process parameters during fiber formation. Though many polymers have been studied for emulsion electrospinning, poly(ε-caprolactone) (PCL) is one of the most studied polymers for this technique. Therefore, electrospinning of PCL based emulsions is highlighted as unique case-study, to provide a detailed theoretical understanding, discussion of experimental results along with their suitable biomedical applications.

Biomimetic Bilayered Scaffolds for Tissue Engineering: From Current Design Strategies to Medical Applications

Tissue damage due to cancer, congenital anomalies, and injuries needs new efficient treatments that allow tissue regeneration. In this context, tissue engineering shows a great potential to restore the native architecture and function of damaged tissues, by combining cells with specific scaffolds. Scaffolds made of natural and/or synthetic polymers and sometimes ceramics play a key role in guiding cell growth and formation of the new tissues. Monolayered scaffolds, which consist of uniform material structure, are reported as not being sufficient to mimic complex biological environment of the tissues. Osteochondral, cutaneous, vascular, and many other tissues all have multilayered structures, therefore multilayered scaffolds seem more advantageous to regenerate these tissues. In this review, recent advances in bilayered scaffolds design applied to regeneration of vascular, bone, cartilage, skin, periodontal, urinary bladder, and tracheal tissues are focused on. After a short introduction on tissue anatomy, composition and fabrication techniques of bilayered scaffolds are explained. Then, experimental results obtained in vitro and in vivo are described, and their limitations are given. Finally, difficulties in scaling up production of bilayer scaffolds and reaching the stage of clinical studies are discussed when multiple scaffold components are used.

Dynamics of CSBD Healing after Implementation of Dentin and Xenogeneic Bone Biomaterial

Autologous dentin is frequently used in guided bone regeneration due to its osteoinductive properties, which come from its similarity to native bone. On the other hand, the xenogeneic bone biomaterial Cerabone^® serves as a biocompatible, but hardly resorbed biomaterial. During bone healing, an inflammatory, vascular, and osteogenic response occurs in which cytokines such as tumor necrosis factor-alpha (TNF-α), vascular endothelial growth factor (VEGF), and osteopontin (OPN) are released locally and systemically. The aim was to follow up the dynamics (on days 3, 7, 15, 21, and 30) of critical-sized bone defect (CSBD) healing after the implantation of bovine devitalized dentin, rat dentin, and xenogeneic bone biomaterial. For this purpose, histological and histomorphometric methods were employed. Additionally, serum concentrations of TNF-α, VEGF, and OPN were monitored in parallel to better understand the biomaterial-dependent systemic response in rats. At the last time interval, the results showed that the bone defect was bridged over in all three groups of biomaterials. The rat dentin group had the highest percentage of bone volume (BV/TV) and the least percentage of residual biomaterial (RB), which makes it the most optimal biomaterial for bone regeneration. Serum concentrations of the TNF-α, VEGF, and OPN refer to systemic response, which could be linked to intense bone remodeling between days 15 and 21 of the bone healing.

Effect of ozone therapy on the modulation of inflammation and on new bone formation in critical defects of rat calvaria filled with autogenous graft

OBJECTIVE

The aim of this study was to evaluate the effect of ozone therapy on new bone formation and inflammation modulation in defects of rat calvaria filled with autogenous bone.

MATERIAL AND METHODS

Critical size defects were created in the calvaria of 24 male Wistar rats. The animals were randomly divided into four groups according to the treatment: G1: clot; G2: clot and covered with xenogenic membrane; G3: particulate autogenous bone graft; G4: autogenous bone graft and application of 3 mL O₂/O₃ gas mixture (10 µg/ml). The defects were filled immediately after surgery with a bilateral retroauricular application, in the region immediately above the incision. After 21 days, the animals were euthanized, and the samples were processed for morphometric evaluations designed to measure both the intensity of the inflammatory infiltrate, and the presence of new bone formation in the defect.

RESULTS

The results showed a lower inflammation score and higher mean of newly formed bone in the region of the defect for the group associated with ozone therapy (G4). The bone formed in the region of the defect could be observed as being more lamellar and mineralized in the case of associated ozone therapy.

CONCLUSION

Ozone therapy represents a promising adjuvant therapy to accelerate tissue regeneration.

Antimicrobial and Pro-Osteogenic Coaxially Electrospun Magnesium Oxide Nanoparticles-Polycaprolactone /Parathyroid Hormone-Polycaprolactone Composite Barrier Membrane for Guided Bone Regeneration

Introduction

An antibacterial and pro-osteogenic coaxially electrospun nanofiber guided bone regeneration (GBR) membrane was fabricated to satisfy the complicated and phased requirements of GBR process.

Methods

In this study, we synthesize dual-functional coaxially electrospun nanofiber GBR membranes by encapsulating parathyroid hormone (PTH) in the core layer and magnesium oxide nanoparticles (MgONPs) in the shell layer (MgONPs-PCL/PTH-PCL). Herein, the physicochemical characterization of MgONPs-PCL/PTH-PCL, the release rates of MgONPs and PTH, and antibacterial efficiency of the new membrane were evaluated. Furthermore, the pro-osteogenicity of the membranes was assessed both in-vitro and in-vivo.

Results

We successfully fabricated a coaxially electrospun nanofiber MgONPs-PCL/PTH-PCL membrane with the majority of nanofibers (>65%) ranged from 0.40~0.60μm in diameter. MgONPs-PCL/PTH-PCL showed outstanding antibacterial potential against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) through the release of MgONPs. We also discovered that the incorporation of MgONPs significantly prolonged the release of PTH. Furthermore, both the in-vivo and in-vitro studies demonstrated that high dosage of PTH promoted pro-osteogenicity of the membrane to improve bone regeneration efficacy with the presence of MgONPs.

Conclusion

The new composite membrane is a promising approach to enhance bone regeneration in periodontitis or peri-implantitis patients with large-volume bone defects.

In vitro evaluation of crosslinked bovine pericardium as potential scaffold for the oral cavity

BACKGROUND

Bovine pericardium (BP) is a scaffold widely used in soft tissues regeneration; however, its calcification in contact with glutaraldehyde, represent an opportunity for its application in hard tissues, such as bone in the oral cavity.

OBJECTIVE

To develop and to characterize decellularized and glutaraldehyde-crosslinked bovine pericardium (GC-BP) as a potential scaffold for guided bone regeneration GBR.

METHODS

BP samples from healthy animals of the bovine zebu breed were decellularized and crosslinked by digestion with detergents and glutaraldehyde respectively. The resulting cell-free scaffold was physical, chemical, mechanical, and biologically characterized thought hematoxylin and eosin staining, DNA quantification, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), uniaxial tensile test, cell viability and live and dead assay in cultures of dental pulp stem cells (DPSCs).

RESULTS

The decellularization and crosslinking of BP appeared to induce conformational changes of the CLG molecules, which led to lower mechanical properties at the GC-BP scaffold, at the same time that promoted cell adhesion and viability of DPSCs.

CONCLUSION

This study suggests that the decellularized and GC-BP is a scaffold with the potential to be used promoting DPSCs recruitment, which has a great impact on the dental area.

Healing Patterns of Non-Collagenated Bovine and Collagenated Porcine Xenografts Used for Sinus Floor Elevation: A Histological Study in Rabbits

Objective: To compare healing of collagenated and non-collagenated xenografts used for maxillary sinus floor elevation. Materials and Methods: Two different xenografts were used: deproteinized bovine bone (DBBM group) and collagenated corticocancellous porcine bone (collagenated group). Healing was studied after 2, 4, and 8 weeks. The loss of dimensions of the elevated area and the percentages of new bone, xenograft remnants, osteoclastic zones, vessels, inflammatory infiltrates, and soft tissues were analyzed. Three regions were evaluated: close to the bone walls (bone wall region), subjacent the sinus mucosa (submucosa region), and the center of the elevated area (middle region). The primary variables were the percentage of new bone and xenograft remnants. Results: Between 2 and 8 weeks, the elevated areas showed a reduction of 16.3% and 52.2% in the DBBM and collagenated groups, respectively (p < 0.01 between the two areas after 8 weeks). After 8 weeks, the highest content of new bone was observed in the bone wall region, which was higher in the collagenated group than in the DBBM group (41.6% and 28.6%, respectively; p < 0.01). A similar quantity of new bone was found between the two groups in other regions. A higher percentage of vessels in all regions evaluated (p < 0.01) and soft tissue in the sub-mucosa region (p < 0.05) was found in the collagenated group than in the DBBM group. Conclusions: The present study showed that both xenografts allowed new bone formation. In comparison with the non-collagenated xenograft, the collagenated xenograft underwent higher resorption, resulting in greater shrinkage of the elevated space after sinus lifting and a higher content of new bone in the regions close to the bone walls. Clinical relevance: In this study, the region adjacent to the bone wall showed the highest new bone content. This region resembles the base of the sinus, closest to the sinus floor and walls, and is the most important region from a clinical point of view because it is where the implant will be installed. Residues of the biomaterial remained after 8 weeks of healing. Other reports have shown that these biomaterial residues may interfere with the integration of implants.

Use of Melatonin/Decorticotomy and Autogenous Bone Graft in Induced 1-Wall Defect

PURPOSE

This study was designed to investigate the effect of intramarrow penetration (IMP) and 1% melatonin (MLN) gel on the remodelling process of autogenous bone graft (ABG) in an induced 1-osseous wall defect model.

METHODS

Sixty-four intrabony induced mandibular defects were created on the distal side of premolars-P1, P2, P3, and P4 (on each side)-in 8 beagle dogs. A ligature-induced periodontitis was initiated in each defect. Defects were then divided into 4 equal groups. Group I was treated with open-flap debridement (OFD) alone, group II was treated with OFD/ABG, group III was treated with OFD/IMP/ABG, and group IV was treated with OFD/ABG/IMP/1% MLN gel. The study parameters were bone fill, histologic analysis, and immunohistochemical evaluation of endothelial nitric oxide synthase (eNOS) expression at 2-week (2W) and 8-week (8W) time intervals.

RESULTS

At 8W, significant differences were revealed amongst all groups regarding the amount of bone fill and eNOS expressions (P < .001). Bone fill percentages were 55.5%, 22.3%, 16.8%, and 0% in groups IV, III, II, and I, respectively. eNOS expressions were 1.68 ± 0.06, 8.43 ± 0.04, 16.80 ± 0.17, and 1.97 ± 0.07 in groups IV, III, II, and I, respectively. The favourable results were in line with group IV.

CONCLUSIONS

According to these preliminary results, defects treated by ABG augmented with IMP and 1% MLN gel revealed a greater amount of bone fill and reduced eNOS expression. This combination is therefore highly suggested as an adjunct to ABG.

Characterization of a Magnesium Fluoride Conversion Coating on Mg-2Y-1Mn-1Zn Screws for Biomedical Applications

MgF₂-coated screws made of a Mg-2Y-1Mn-1Zn alloy, called NOVAMag^® fixation screws (biotrics bioimplants AG), were tested in vitro for potential applications as biodegradable implants, and showed a controlled corrosion rate compared to non-coated screws. While previous studies regarding coated Mg-alloys have been carried out on flat sample surfaces, the present work focused on functional materials and final biomedical products. The substrates under study had a complex 3D geometry and a nearly cylindrical-shaped shaft. The corrosion rate of the samples was investigated using an electrochemical setup, especially adjusted to evaluate these types of samples, and thus, helped to improve an already patented coating process. A MgF₂/MgO coating in the µm-range was characterized for the first time using complementary techniques. The coated screws revealed a smoother surface than the non-coated ones. Although the cross-section analysis revealed some fissures in the coating structure, the electrochemical studies using Hanks' salt solution demonstrated the effective role of MgF₂ in retarding the alloy degradation during the initial stages of corrosion up to 24 h. The values of polarization resistance (Rp) of the coated samples extrapolated from the Nyquist plots were significantly higher than those of the non-coated samples, and impedance increased significantly over time. After 1200 s exposure, the Rp values were 1323 ± 144 Ω.cm² for the coated samples and 1036 ± 198 Ω.cm² for the non-coated samples, thus confirming a significant decrease in the degradation rate due to the MgF₂ layer. The corrosion rates varied from 0.49 mm/y, at the beginning of the experiment, to 0.26 mm/y after 1200 s, and decreased further to 0.01 mm/y after 24 h. These results demonstrated the effectiveness of the applied MgF₂ film in slowing down the corrosion of the bulk material, allowing the magnesium-alloy screws to be competitive as dental and orthopedic solutions for the biodegradable implants market.

Janus electro-microenvironment membrane with surface-selective osteogenesis/gingival healing ability for guided bone regeneration

Guided bone regeneration is widely applied in clinical practice to treat alveolar bone defects. However, the rate of healing of severe alveolar bone defects is slow, and there is a high incidence of soft tissue wound dehiscence. In this study, we propose a barrier membrane with a Janus electro-microenvironment (JEM) to achieve side-selective bone regeneration and soft tissue healing. The JEM membrane was constructed using a polarized polyvinylidene fluoride ferroelectric membrane with different surface potentials on either side. It promoted osteogenic differentiation and bone regeneration on the negatively polarized side (JEM-) and soft tissue regeneration on the positively polarized side (JEM+). Further investigation revealed that the JEM-mediated promotion of bone formation was related to mitochondrial autophagy, as indicated by depolarization of the mitochondrial membrane potential and the expression of LC3, Pink I, and Parkin. Moreover, the gingival healing promoted by JEM+ was related to oxidative phosphorylation in mitochondria, as indicated by the upregulation of mitochondrial complexes I–V and an increase in ATP generation. The design concept of the JEM provides a new avenue for regulating tissue regeneration between different tissue interfaces.

Channel Aperture Characteristics of Carbonate Apatite Honeycomb Scaffolds Affect Ingrowths of Bone and Fibrous Tissues in Vertical Bone Augmentation

Synthetic scaffolds with the ability to prevent fibrous tissue penetration and promote bone augmentation may realize guided bone regeneration without the use of a barrier membrane for dental implantation. Here, we fabricated two types of honeycomb scaffolds of carbonate apatite, a bone mineral analog, whose channel apertures were square (HC-S) and rectangular (HC-R). The side lengths of the HC-Ss and HC-Rs were 265.8 ± 8.9; 817.7 ± 2.4 and 267.1 ± 5.2 μm, respectively. We placed cylindrical HC-Ss and HC-Rs on the rabbit calvaria. At 4 weeks post-implantation, the HC-Ss prevented fibrous tissue penetration from the top face via the channels, which allowed the new bone to reach the top of the scaffold from the bottom face or the calvarium. In contrast, in the HC-Rs, fibrous tissues filled the channels in the top region. At 12 weeks post-implantation, the HC-Ss were partially replaced with new bone. In the top region of the HC-Rs, although new bone had formed, fibrous tissue remained. According to the findings here and in our previous study, the longer side length rather than the shorter side length of a rectangular scaffold channel aperture is the dominant factor that affects fibrous tissue penetration and new bone augmentation. Furthermore, even though channel aperture areas are similar, bone and fibrous tissue ingrowths are different when the aperture shapes are different.

Flap Extension Technique Using Intrasocket Granulation Tissue in Peri-Implant Osseous Defect: Case Series

A compromised extraction socket is characterized by severe bone resorption around neighboring teeth and is often occupied with thick intrasocket granulation tissue (IGT). Guided bone regeneration (GBR) is a procedure that can preserve the bone volume around extraction sockets, and it can also be combined with immediate implant placement. However, an early exposure of GBR sites is a possible complication because it increases the risk of infection and can inhibit successful bone regeneration. The purpose of these case series is to introduce a novel, surgical procedure that can prevent the exposure of GBR sites by using IGT for flap extension during immediate implant placement in compromised extraction sockets. The technique was successfully performed in six patients. For successful flap closure, the inner portion of the IGT was dissected so that the flap was properly extended with the base of IGT attached to the flap for blood supply. Periosteal releasing incisions were not performed. The IGT was first sutured to the palatal flap with resorbable sutures, and then the overlying flap was closed with additional sutures. There was no post-operative exposure of the surgical GBR site in any of the patients, and the location of the mucogingival junction remained unchanged. All grafted sites also achieved sufficient bone regeneration. Within the limitations, this case series demonstrates the potential use of IGT, a concept which was previously obsolete.

Influence of melatonin associated with the Bio-Gide® membrane on osteoblast activity: an in vitro Study

Melatonin (MLT) is a hormone responsible for regulating several physiological processes. It has been shown that MLT can be an important mediator in bone formation and stimulation, promoting osteoblast differentiation. In clinical practice, in tissue regeneration procedures, it is necessary to use membranes or barriers, associated with biomaterials, or not. The aim of this in vitro study was to assess the effect of melatonin on the activity of osteoblastic cells, associated, or not, with a resorbable collagen membrane (Bio-Gideä). For this, mice-derived pre-osteoblastic cells MC3T3 obtained from the ATCC (American Type Culture Collection) were used. Cultured cells were subject to the following treatments: MLT with a concentration of 1mM, a Bio-Gideä membrane and a membrane associated with MLT (Bio-Gideä + MLT). Proliferation and cell viability assays and protein lysate (ELISA test) quantification for the BMP-2 protein were carried out, in periods of 72 hours, 7 days and 10 days. After analyzing the data (one-way ANOVA, alpha=5%) it was observed that when MLT was used in isolation, there was an increase in cell proliferation and viability in osteoblastic cells (p<0.05). But, when MLT was associated with resorbable membranes, there was an inverse behavior, both in terms of proliferation and viability (p<0.05). In the case of the ELISA test, no secretion of BMP-2 was detected in any of the analyzed groups. It is concluded that MLT has a stimulatory effect on osteoblasts, but, when associated with Bio-Gideä resorbable membranes, it does not show any viable action in osteoblastic cell stimulation.

Current Advances of Three-Dimensional Bioprinting Application in Dentistry: A Scoping Review

Three-dimensional (3D) bioprinting technology has emerged as an ideal approach to address the challenges in regenerative dentistry by fabricating 3D tissue constructs with customized complex architecture. The dilemma with current dental treatments has led to the exploration of this technology in restoring and maintaining the function of teeth. This scoping review aims to explore 3D bioprinting technology together with the type of biomaterials and cells used for dental applications. Based on PRISMA-ScR guidelines, this systematic search was conducted by using the following databases: Ovid, PubMed, EBSCOhost and Web of Science. The inclusion criteria were (i) cell-laden 3D-bioprinted construct; (ii) intervention to regenerate dental tissue using bioink, which incorporates living cells or in combination with biomaterial; and (iii) 3D bioprinting for dental applications. A total of 31 studies were included in this review. The main 3D bioprinting technique was extrusion-based approach. Novel bioinks in use consist of different types of natural and synthetic polymers, decellularized extracellular matrix and spheroids with encapsulated mesenchymal stem cells, and have shown promising results for periodontal ligament, dentin, dental pulp and bone regeneration application. However, 3D bioprinting in dental applications, regrettably, is not yet close to being a clinical reality. Therefore, further research in fabricating ideal bioinks with implantation into larger animal models in the oral environment is very much needed for clinical translation.

Customized 3D-Printed Titanium Mesh Developed for an Aesthetic Zone to Regenerate a Complex Bone Defect Resulting after a Deficient Odontectomy: A Case Report

Background and Objectives: Alveolar ridge augmentation in the complex bone defect is a popular topic in implantology. Guided bone regeneration (GBR) is one of the most commonly applied methods to reconstruct alveolar bone. The application of a membrane is the fundamental principle of GBR. There are many membrane types used in oral surgery, but the advantage of the titanium mesh is the rigidity which provides space maintenance and prevents contour collapse. The smooth surface also reduces bacterial contamination. Using computer-aided design (CAD) and computer-aided manufacturing (CAM) in dentistry allows us to obtain the perfect architecture form of the mesh, which covers and protects the bone reconstruction. Case presentation: We present a surgical case of a 27-year-old female patient with severe aesthetic bone atrophy after a deficient odontectomy. Based on the GBR clinical applications, the technique consists of bone reconstruction and a customized titanium mesh application. Using mesh titanium in this case presentation was a reliable alternative to perform a lateral alveolar bone augmentation and reconstruct ridge deformities before reaching an ideal implant placement. Conclusions: According to our case report, the customized titanium mesh could be a valuable option for guided bone regeneration in aesthetic maxillary defects.

Comparative Analysis of Implant Prosthesis Treatment Planning and Execution Following Bone Repair Procedures Using Dynamic Surgical Navigation in Augmented Areas

Successful implant placement in augmented sites depends on the appropriate bone volume and quality, as well as careful planning of the procedure. Minimizing risks during the surgical and healing phases is also of great importance. A very promising technique has been introduced, which partially meets the above criteria. This technique is designed to increase the precision and reduce the invasiveness associated with surgical procedures during implantation. The aim of this clinical study was to analyze the accuracy of computer-guided implant surgery in augmented sites in patients treated with dental implants introduced using dynamic implant navigation. Eleven healthy patients who had planned and performed implant-prosthetic treatment after bone augmentation were analyzed. Twenty-three implants were placed with Navident dynamic navigation using the tissue punch flapless technique. This study evaluated the position of the inserted implant relative to the virtual plan and determined the correlation. The treatments were successful in all the treated patients, and the integration period (3 or 6 months) was uneventful and enabled implant-prosthetic treatment. The accuracy values provided in this study are comparable to, but not better than, data provided in the literature on dynamic and static computer-assisted surgery. Dynamic navigation may improve the quality and safety of surgical procedures and reduce the risk of complications.