Mechanisms of guided bone regeneration: a review

Tissue Sources Influence the Morphological and Morphometric Characteristics of Collagen Membranes for Guided Bone Regeneration

(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.

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.

Simultaneous Osseo- and Odontointegration of Titanium Implants: Description of Two Cases in Human and Animal Models and Review of Their Experimental and Clinical Implications

Two cases of calcified bone and dental tissue integration with titanium implants are presented, along with a review of the literature on their experimental and clinical implications. First, histological analyses of a titanium implant extracted from a patient with iimplant disease revealed the integration of both dental and bone tissue on the implant's surface. Secondly, a biocompatibility study in an animal model documented two implants in contact with tooth roots. Samples from both animal and human models demonstrated simultaneous osseointegration and dental tissue neoformation, with the latter attributed to the activity of cementoblasts. The literature review confirms the formation of cementum around dental implants in contact with teeth. Certain clinical reports have proposed the insertion of implants into bone sites containing impacted teeth as a conservative treatment alternative, avoiding the need for tooth extraction surgery and demonstrating the successful integration of teeth, bone, and dental implants. Furthermore, the documented natural formation of periodontal tissues around dental implants provided a foundation for tissue engineering studies aimed at realizing implant-bone relationships similar to those of natural bone-tooth structures. The primary challenges remain the long-term preservation of periodontal-like tissue formed on implants and the imparting of functional proprioceptive properties.

Bone graft substitutes and dental implant stability in immediate implant surgery: a systematic review and meta-analysis

INTRODUCTION

Implant dentistry is currently being revolutionized by breakthroughs in techniques, technology, and material, there are few systematic reviews and meta-analyses that examine the effects of utilizing different bone graft substitutes in immediate implant placement surgeries.

AIM

The purpose of this research is to systematically review and meta-analyze the effect that different bone graft substitutes have on implant stability when concurrently utilized in patients undergoing immediate implant surgeries.

METHODOLOGY

The PICO criteria were used to construct the focused question, and the systematic review has been outlined as per the PRISMA guidelines. The revised Cochrane risk-of-bias method for randomized trials was used to assess the risk of bias for the selected articles. To derive estimates for the results, random effects meta-analysis was conducted on the selected articles.

RESULTS

The electronic databases were searched and a total of 1583 articles were identified. After title and abstract screening and due to problems in retrieval a further 1358 articles were eliminated. Fifteen articles were finally chosen to be qualified for review. Of which full text evaluation of 5 articles were found to meet the eligibility criteria and were therefore included in the systematic review.

CONCLUSION

This systematic review and meta-analysis on the stability of dental implants and bone graft substitutes in immediate implant surgery, was unable to draw any conclusions and established no statistically significant correlation between the different types of grafts used and implant stability.

Intraosseous Delivery of Mesenchymal Stem Cells for the Treatment of Bone and Hematological Diseases

Mesenchymal stem cells are used most in regenerative medicine due to their capacities in differentiation and immune modulation. The intraosseous injection of MSC into the bone has been recommended because of expected outcomes for retention, bioavailability, and enhanced therapeutic efficacy, particularly in conditions involving the bone, such as osteoporosis and osteonecrosis. A review of the intraosseous delivery of mesenchymal stem cells in comparison with intravenous and intra-arterial delivery methods will be subjected to critical examination. This delivery mode fares better regarding paracrine signaling and immunomodulation attributes, which are the cornerstone of tissue regeneration and inflammation reduction. The local complications and technical challenges still apply with this method. This study was more focused on further research soon to be conducted to further elucidate long-term safety and efficacy of intraosseous mesenchymal stem cell therapy. Though much has been achieved with very impressive progress in this field, it is worth noting that more studies need to be put into place so that this technique can be established as a routine approach, especially with further research in biomaterials, gene therapy, and personalized medicine.

Effect of bioceramic inclusions on gel-cast aliphatic polymer membranes for bone tissue engineering applications: An in vitro study

BACKGROUND

Polylactic acid (PLA) has been extensively used in tissue engineering. However, poor mechanical properties and low cell affinity have limited its pertinence in load bearing bone tissue regeneration (BTR) devices.

OBJECTIVE

Augmenting PLA with β-Tricalcium Phosphate (β-TCP), a calcium phosphate-based ceramic, could potentially improve its mechanical properties and enhance its osteogenic potential.

METHODS

Gels of PLA and β-TCP were prepared of different % w/w ratios through polymer dissolution in acetone, after which polymer-ceramic membranes were synthesized using the gel casting workflow and subjected to characterization.

RESULTS

Gel-cast polymer-ceramic constructs were associated with significantly higher osteogenic capacity and calcium deposition in differentiated osteoblasts compared to pure polymer counterparts. Immunocytochemistry revealed cell spreading over the gel-cast membrane surfaces, characterized by trapezoidal morphology, distinct rounded nuclei, and well-aligned actin filaments. However, groups with higher ceramic loading expressed significantly higher levels of osteogenic markers relative to pure PLA membranes. Rule of mixtures and finite element models indicated an increase in theoretical mechanical strength with an increase in β-TCP concentration.

CONCLUSION

This study potentiates the use of PLA/β-TCP composites in load bearing BTR applications and the ability to be used as customized patient-specific shape memory membranes in guided bone regeneration.

Antibiotic-Loaded Dendrimer Hydrogels in Periodontal Bone Regeneration: An In Vitro Release Feasibility Study

The prescription of a course of oral antibiotics following bone grafting procedures is a common practice in clinical periodontics to reduce surgical site infections. The goal of this study is to characterize the release profile of antibiotics via local delivery using dendrimer hydrogels (DH) and to analyze the effect of two different particulate bone allografts on the release of the antibiotics in vitro. DH were synthesized from polyamidoamine (PAMAM) dendrimer G5 and polyethylene glycol diacrylate, and cefazolin was chosen as the antibiotic. The antibiotic-loaded samples were bathed in PBS and incubated at 37 °C; aliquots were taken (1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 12 h, 24 h, 48 h, 72 h) and analyzed using HPLC to determine the amounts of released cefazolin. In samples with DH, the estimated maximum concentration of cefazolin was 36.97 ± 2.39 μg/mL (95% CI: 34.58-39.36) with 50% released in 4.17 h (95%: 3.26-5.07) and an estimated growth rate of 0.27 (95% CI: 0.17-0.37). For samples without DH, the estimated maximum concentration of cefazolin was 167.4 ± 7.0 μg/mL (95% CI: 160.4-174.4) with 50% released in 2.36 h (95% CI: 2.05-2.67) and an estimated growth rate of 0.70 (95% CI: 0.54-0.87). We conclude that DH are a promising platform for sustained antibiotic release and that the presence of bone grafts did not significantly affect their release.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

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.

Lateral Alveolar Ridge Augmentation with Autogenous Tooth Roots and Staged Implant Placement-5-Year Follow-Up Case Series

Background/Objectives: Alveolar bone augmentation before implant placement is a safe and effective treatment option for the reconstruction of a deficient alveolar ridge. According to recent research, permanent teeth have been used as bone graft materials, with studies confirming their clinical and histological results. This study aimed to evaluate the efficacy of alveolar ridge augmentation with autogenous tooth roots and staged implant placement, and peri-implant tissue stability in augmented sites. Methods: A total of 20 augmentations with autogenous tooth roots on mandibular alveolar ridges in 15 patients were performed. After 6 months, the ridge width (RWa) and ridge width gain (RWg) were measured. Titanium dental implants were placed in grafted sites and loaded 10 weeks after placement. Clinical parameters (bleeding on probing-BOP; probing depth-PD; mucosal recession-MR; and clinical attachment level-CAL) were assessed 2 months (T1), 3 years (T2), and 5 years (T3) after implant loading. Results: The mean RWa was 6.71 ± 0.74 mm, and the RWg was 3.15 ± 0.54 mm, respectively. No statistically significant differences were observed for clinical parameters (BOP, PD, MR, and CAL) among different time points (p > 0.05). Conclusions: Autogenous tooth roots represent a viable solution for alveolar ridge augmentation and implant placement, providing a stable environment for peri implant tissues.

Supra-Alveolar Bone Regeneration: Progress, Challenges, and Future Perspectives

Periodontitis is a highly prevalent disease that damages the supporting tissues of a tooth, including the alveolar bone. Alveolar bone loss owing to periodontitis is broadly categorized as supra-alveolar and intra-alveolar bone loss. In intra-alveolar bone loss, the defect has an angular or oblique orientation to the long axis of the tooth in an apical direction. In contrast, the defect is perpendicular to the long axis of the tooth in supra-alveolar bone loss. Unlike intra-alveolar bone defects, supra-alveolar bone defects lack supporting adjacent space, which makes supra-alveolar bone regeneration more challenging. In addition, the limited availability of resources in terms of vascularity and underlying tissues is another obstacle to supra-alveolar bone regeneration. Currently, supra-alveolar bone loss is the least predictable periodontal defect type in regenerative periodontal therapy. In addition, supra-alveolar bone loss is much more common than other alveolar bone loss. Despite its prevalence, research on supra-alveolar bone regeneration remains sparse, indicating an unmet need for significant research efforts in this area. This review summarize recent advances, obstacles, and future directions in the field of supra-alveolar bone regeneration. We discuss the biomaterials, bioactive molecules, and cells that have been tested for supra-alveolar bone regeneration, followed by pre-clinical and clinical approaches employed in this field. Additionally, we highlight obstacles and present future directions that will propel supra-alveolar bone research forward.

Adhesion of Candida albicans on PTFE membranes used in guided bone regeneration

OBJECTIVES

Guided bone regeneration (GBR) is a core procedure used to regenerate bone defects. The aim of the study was to investigate the adherence of Candida albicans on six commercially available polytetrafluoroethylene (PTFE) membranes used in GBR procedures and the subsequent clinical consequences.

MATERIALS AND METHODS

Six commercially available PTFE membranes were tested. Two of the membranes had a textured surface and the other four a plane, nontextured one. C. albicans (ATCC 24433) was cultured for 24 h, and its cell surface hydrophobicity was assessed using a modified method. C. albicans adhesion to membrane discs was studied by scanning electron microscopy (SEM) and real-time polymerase chain reaction (PCR).

RESULTS

C. albicans was found to be hydrophobic (77.25%). SEM analysis showed that C. albicans adherence to all membranes examined was characterized by patchy, scattered, and small clustered patterns except for one nontextured membrane with a most rough surface in which a thick biofilm was observed. Real-time PCR quantification revealed significantly greater adhesion of C. albicans cells to PTFE membranes than the control membrane (p ≤ .001) with the membranes having a textured surface exhibiting the highest count of 2680 × 104 cells/ml compared to the count of 707 × 104 cells/mL on those with a nontextured one (p ≤ .001). One membrane with nontextured surface, but with most rough surface was found to exhibit the highest count of 3010 × 104 cells/ml (p ≤ .05).

CONCLUSION

The results of this study indicate that C. albicans adhesion on membranes' surfaces depends on the degree of surface roughness and/or on the presence of a texture. Textured PTFE membranes and/or membranes high roughness showed significantly more adhered C. albicans cells. These findings can impact the surgeon's choice of GBR membrane and postoperative maintenance.

Research status and prospects of biodegradable magnesium-based metal guided bone regeneration membranes

Biodegradable magnesium-based metal guided bone regeneration (GBR) membranes possess excellent mechanical properties, biodegradability, and osteopromotive capabilities, making them ideal implants for the treatment of maxillofacial bone defects. This review summarizes the current status and future research trends related to magnesium-based GBR membranes. First, the research history and application fields of magnesium-based metals are introduced, and the advantages of the use of magnesium-based materials for GBR membranes, including their mechanical properties, biocompatibility, osteopromotive performance, and underlying mechanisms are discussed. Finally, this review addresses the current limitations of magnesium-based GBR membranes and their applications and prospects in the field of dentistry. In conclusion, considerable advancements have been in fundamental and translational research on magnesium-based GBR membranes, which lays a crucial foundation for the treatment of maxillofacial bone defects.

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.

Osteoproductivity of Injectable Bone Grafts with and without Ostrich Eggshell Membrane Protein in Rabbit Femur

BACKGROUND

The aim of this study was to evaluate the biocompatibility and effectiveness in terms of osseointegration of dental implants composed of novel injectable bone grafts with and without ostrich eggshell particles and membrane protein in rabbit femur.

METHODS

Sixteen adult male New Zealand rabbits were used in this study. A bone defect was created in each animal's right and left femur, and a dental implant was placed adjacent to the defect. Two graft materials were prepared, one containing the membrane protein and the other not. In two groups, the defects were filled with these materials. In the negative control group (NC, (n:8)), the defects were left empty. A commercial product of biphasic calcium sulfate was used as a positive control material (PC, n = 8). The graft groups were defined as the group with the membrane protein (MP+, (n:8)), and without the membrane protein (MP-, n:8). The animals were euthanized at the 12th week after surgery. The samples were investigated using histology, histomorphometry, and micro-computed tomography. Data were statistically analyzed using one-way ANOVA and Tukey's tests (p = 0.05).

RESULTS

Both the PC and MP+ groups had similar newly formed bone areas, and the mean values of these groups were significantly (p < 0.05) higher than those of the MP- and NC groups. The PC group had the highest amount of unresorbed material, while the MP- group had the lowest amount of unresorbed material. The bone-implant contact (BIC) scores of the PC and MP+ groups were significantly higher (p < 0.05) than that of the NC group. The connective tissue area of the PC group was the lowest, which was significantly lower than the other groups (p < 0.05).

CONCLUSIONS

The grafts produced are highly biocompatible and also showed osteoproductivity. Their cost-effectiveness and osteoproductive activity require further investigation.

Prognosis recovery score of apical surgery Guided Bone Regeneration using cone beam computed tomography and digital bioinformatics

Objective

Guided Bone Regeneration (GBR) is a dental surgical procedure that uses barrier membranes to prevent soft tissue invasion and conduct new bone growth. This study aimed to define a Prognosis Recovery score (PR score) to objectively classify post-surgery responders from non-responder patients who underwent GBR using Cone Beam Computed Tomography (CBCT).

Methods

This prospective-observational-longitudinal-cohort study recruited 250 individuals who were assigned to: Conventional-Apical-Surgery (CAS, n = 39), Apical-Surgery using human fascia lata Membrane placement (ASM, n = 42), and Apical-Surgery using human fascia lata Membrane placement and lyophilized allograft Bone powder (ASMB, n = 39); and Apical-Surgery using collagen membrane Porcine origin and Bovine Bone-matrix (ASPBB, n = 130), an independent external validation cohort. Surgery was performed, and evolution was monitored by CBCTs at 0, 6-, 12-, 18-, and 24 months post-surgery.

Results

Normalized lesion volumes were calculated, and non-linear time evolution morphology curves were characterized. The three-time evolution bone growth patterns were: a linear tendency (PR0), "S'' shaped log-logistic (PR1), and "C" cellular growth (PR2). The treatment success rates were PR2-46 %, PR2-88 %, and PR2-95 %/PR1-5% for CAS, ASM, and ASMB groups. The xenograft ASPBB counterpart achieved PR2-92 % and PR1-8%. The score PR had a sensitivity, specificity, and accuracy of 100 %.

Conclusions

Patients' treatment success can be quantitatively, objectively, and precisely predicted with the Prognosis Recovery score (using only two CBCTs), according to their biological response to allograft or xenograft materials (time-evolution bone growth curves), reducing cost and radiation exposure.

Clinical significance

Through digital imaging and bioinformatic analysis of bone regeneration observed in CBCTs, we defined a Prognosis Recovery (PR) score using only two CBCT volume assessments (0 and 6 months). The PR score allowed us to define three time-evolution curves depending on the biomaterials used and to classify patients in a quantitative, objective, and accurate way.

Effect of Different Graft Material Consistencies in the Treatment of Minimal Bone Dehiscence: A Retrospective Pilot Study

Among different therapeutic strategies proposed in the case of bone volume deficit, guided bone regeneration (GBR) is a consolidated surgical procedure. The objective of this study is to retrospectively evaluate the behavior of two bone grafts with different consistencies in the GBR procedure by measuring the volumetric tissue changes 1 year after surgery. For this retrospective analysis, 25 cases of GBR with simultaneous implant insertion were selected. A total of 13 were grafted with a porcine cortico-cancellous bone mix (CCBM group), and 12 were grafted with a pre-hydrated granulated cortico-cancellous bone mix of porcine origin blended with 20% TSV gel (Collagenated-CCBM). A collagen membrane was fixed to cover the bone defect. A total of 42 implants were placed with computer-guided surgery. Preoperative and 12-month postoperative digital impressions were used to evaluate dimensional changes. Student's t-test used for independent samples showed no statistically significant differences between the integrated distance (p = 0.995) and mean distance (p = 0.734). The mean integrated distance in the CCBM group was 41.80 (SD. 101.18) compared to a mean of 42.04 (SD. 66.71) in the Collagenated-CCBM group. Given the limitations of this study, in patients with peri-implant bone dehiscence, simple heterologous and collagenated heterologous cortico-cancellous bone grafts are suitable for filling the bone defect to promote bone regeneration, although further studies are needed.

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.

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).

Applications of a minimally invasive roll flap technique in peri-implant soft-tissue augmentation - A case series

Deficiency of peri-implant tissue contours is commonly seen due to the process of alveolar ridge resorption after tooth loss. Minor deficiencies can be effectively managed by soft-tissue augmentation procedures to create a more biomimetic tissue contour. The minimally invasive roll technique is a modification of the palatal roll-flap technique and can be carried out at both stages of implant surgery. In this technique, the crestal keratinized tissue is marked and de-epithelialized using a circular partial-thickness incision. The crestal connective tissue is then reflected using a lingual full-thickness semi-circular incision, keeping the buccal attachment intact. This buccal attachment serves as the pedicle. The crestal connective tissue is then rolled into a pouch on the buccal aspect of the ridge to obtain soft-tissue augmentation. The present case study documents the clinical results of the minimally invasive roll flap technique (MIRT) in three clinical scenarios, namely single-stage implant surgery, second-stage implant surgery, and anterior esthetic soft-tissue contouring. In all the cases, excellent soft-tissue contour and thickness has been obtained around dental implants. The MIRT is a simple and efficient technique for areas that require minor soft-tissue augmentation. The technique can be used both in the maxilla and the mandible and facilitates a suture-free surgery.

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.

Barrier membranes for periodontal guided bone regeneration: a potential therapeutic strategy

Periodontal disease is one of the most common oral diseases with the highest incidence world-wide. In particular, the treatment of periodontal bone defects caused by periodontitis has attracted extensive attention. Guided bone regeneration (GBR) has been recognized as advanced treatment techniques for periodontal bone defects. GBR technique relies on the application of barrier membranes to protect the bone defects. The commonly used GBR membranes are resorbable and non-resorbable. Resorbable GBR membranes are divided into natural polymer resorbable membranes and synthetic polymer resorbable membranes. Each has its advantages and disadvantages. The current research focuses on exploring and improving its preparation and application. This review summarizes the recent literature on the application of GBR membranes to promote the regeneration of periodontal bone defects, elaborates on GBR development strategies, specific applications, and the progress of inducing periodontal bone regeneration to provide a theoretical basis and ideas for the future application of GBR membranes to promote the repair of periodontal bone defects.

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.

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.

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.

Preclinical Evaluation of Bioactive Scaffolds for the Treatment of Mandibular Critical-Sized Bone Defects: A Systematic Review

This systematic review evaluated current in vivo research on regenerating critical-sized mandibular defects and discussed methodologies for mandibular bone tissue engineering. Out of the 3650 articles initially retrieved, 88 studies were included, and all studies that used a scaffold reported increased bone formation compared to negative controls. Combining scaffolds with growth factors and mesenchymal stem cells improved bone formation and healing. Bone morphogenic proteins were widely used and promoted significant bone formation compared to controls. However, discrepancies between studies exist due to the various methodologies and outcome measures used. The use of scaffolds with bioactive molecules and/or progenitor cells enhances success in mandibular bone engineering. Scaffold-based mandibular bone tissue engineering could be introduced into clinical practice due to its proven safety, convenience, and cost-effectiveness.

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.