Effect of membrane exposure on guided bone regeneration: A systematic review and meta-analysis

Subperiosteal implants constructed with digital technology: A systematic review

STATEMENT OF PROBLEM

Atrophied jaw is a condition where there is insufficient bone quantity and quality. Several treatment plans are available for treating atrophied jaws, including subperiosteal implants.

PURPOSE

To evaluate the spectrum of subperiosteal implants for severely atrophied jaws using digital technology.

MATERIALS AND METHODS

An electronic and manual search was conducted in the PubMed, Scopus, and Google Scholar databases. Publications of cohort studies, case series, and case reports written in English without data restrictions that reported on subperiosteal implant management of patients with severely atrophied jaws in a completely and partially edentulous population.

RESULTS

A total of 26 articles, comprising 302 cases, were analyzed. In patients with severely atrophied jaws. The success rate was 87.7%, the surviving rate was 95.3%. The most common complications were biological, such as dehiscence and framework exposure. The rates of biologic complications were 11.5%, and the rates of prosthetic problems were 5.9%.

CONCLUSIONS

Subperiosteal implants designed and constructed using digital technology are a promising treatment in the short term. Attention should be directed to decrease the biological complication. Correct designing, implanting, fixing, and patient selection and maintenance are critical for the success of the treatment. Longer prospective studies with larger population are needed to view the effect on hard and soft tissue.

Healing patterns of alveolar bone following ridge preservation procedures

OBJECTIVES

Examine the histomorphometric bone composition, following alveolar ridge preservation techniques and unassisted socket healing.

MATERIALS AND METHODS

Forty-two patients (42) requiring a single rooted tooth extraction were randomly allocated into three groups (n = 14 per group): Group 1: Guided Bone Regeneration (GBR) using deproteinised bovine bone mineral (DBBM) and a porcine collagen membrane; Group 2: Socket Seal (SS) technique using DBBM and a porcine collagen matrix; Group 3: Unassisted socket healing (Control). Trephined bone biopsies were harvested following a 4-month healing period. Forty-two samples underwent Back-Scattered Electrons -Scanning Electron Microscopy (BSE-SEM) imaging, with 15 samples examined using Xray Micro-Tomography (XMT) (n = 6 for each GBR/SS and n = 3 Control). Images were analysed to determine the percentage (%) of connective tissue, new bone formation, residual DBBM particles and direct bone to DBBM particle contact (osseointegration).

RESULTS

BSE-SEM analysis demonstrated that new bone formation was higher in the Control (45.89% ± 11.48) compared to both GBR (22.12% ± 12.7/p < .004) and SS (27.62% ± 17.76/p < .005) groups. The connective tissue percentage in GBR (49.72% ± 9), SS (47.81% ± 12.57) and Control (47.81% ± 12.57) groups was similar. GBR (28.17% ± 16.64) and SS (24.37% ± 18.61) groups had similar levels of residual DBBM particles. XMT volumetric analysis indicated a lower level of bone and DBBM particles in all test groups, when matched to the BSE-SEM area measurements. Osseointegration levels (DBBM graft and bone) were recorded at 35.66% (± 9.8) for GBR and 31.18% (± 19.38) for SS.

CONCLUSION

GBR and SS ARP techniques presented with less bone formation when compared to unassisted healing. GBR had more direct contact/osseointegration between the DBBM particles and newly formed bone.

Role of Sticky Bone in the Management of Various Alveolar Bone Defects: A Systematic Review

AIM

This systematic review aimed to evaluate the effectiveness of sticky bone in managing various alveolar bone defects, examining both its benefits and drawbacks.

MATERIALS AND METHODS

The review adhered to PRISMA guidelines and employed a thorough search strategy using major databases, medical subject headings (MeSH) keywords, and Boolean operators. As a result, the systematic review identified 12 studies focusing on the efficacy of sticky bone in treating alveolar bone defects. Inclusion criteria consisted of randomized controlled trials and case series reporting on the outcomes of sticky bone use for bone defect treatment. Two examiners meticulously performed screening, data extraction, and bias assessment, with the risk of bias evaluated using the Cochrane tool.

RESULT

The findings indicated significant improvements in bone quality, width, height, and volume, with enhanced predictability in socket preservation and implant placement. Sticky bone was particularly effective in ridge augmentation, guided bone regeneration, and filling periodontal defects, often outperforming alternatives like concentrated growth factors (CGFs) and autologous fibrin glue (AFG). It simplified procedures and reduced resorption during healing, underscoring its value as a versatile adjunct in bone reconstruction surgery.

CONCLUSION

Sticky bone demonstrated exceptional results in various oral surgeries, effectively addressing issues such as furcation defects, bone loss, and ridge augmentation, with significant clinical and radiographic improvements. Further research is needed to explore its full potential and refine protocols for broader oral surgery and periodontics applications.

A Novel Device for the Evaluation of In Vitro Bacterial Colonization in Membranes for Guided Tissue and Bone Regeneration

Purpose: To evaluate, in vitro, the efficiency of a novel apparatus to test the adherence and penetration of bacteria on different membranes for guided regeneration. Methodology: To create the 3D device, Computer Aided Design/Computer Aided Manufacturing (CAD/CAM) systems were used. Three types of biomaterials were tested (n = 6): (DT) a collagen membrane; (DS) a polymer membrane; and (LP) a dense polytetrafluoroethylene barrier. The biomaterials were adapted to the apparatuses and challenged with two different monospecies bacterial culture of A. actinomycetemcomitans b and S. mutans. After 2 h, bacterial adherence and penetration were quantified by counting the number of colony-forming units (CFUs). Two specimens from each group were used for image analysis using Confocal Laser Scanning Microscopy. Statistical analysis was performed. Findings: The DS group had a higher adherence of S. mutans compared to A. actinomycetemcomitans b (p = 0.05). There was less adherence of A. actinomycetemcomitans b in the DS group, compared to the LP (p = 0.011) and DT (p < 0.001) groups. Only the membranes allowed penetration, which was blocked by barriers. The DT group allowed a greater penetration of S. mutans to occur compared to A. actinomycetemcomitans b (p = 0.009), which showed a higher penetration into the DS membranes compared to S. mutans (p = 0.016). The penetration of A. actinomycetemcomitans b through DS was higher compared to its penetration through DT and LP (p < 0.01 for both). DT and DS allowed a greater penetration of S. mutans to occur compared to LP, which prevented both bacterial species from penetrating. Conclusion: The apparatus allowed for the settlement and complete sealing of the biomaterials, enabling standardization.

Anti-Wound Dehiscence and Antibacterial Dressing with Highly Efficient Self-Healing Feature for Guided Bone Regeneration Wound Closure

Guided bone regeneration (GBR) is a well-established technique for preserving and enhancing alveolar ridge structures. Success in GBR relies on fulfilling the Primary wound closure, Angiogenesis, Space maintenance, and Stability (PASS) principles. Conventional methods, involving titanium meshes and sutures, have drawbacks, including the need for secondary removal and customization challenges. To address these issues, an innovative multifunctional GBR dressing (MGD) based on self-healing elastomer (PUIDS) is introduced. MGD provides sutureless wound closure, prevents food particle accumulation, and maintains a stable environment for bone growth. It offers biocompatibility, bactericidal properties, and effectiveness in an oral GBR model. In summary, MGD provides a reliable, stable osteogenic environment for GBR, aligning with PASS principles and promoting superior post-surgery bone regeneration.

Ultrasound-based jawbone surface quality evaluation after alveolar ridge preservation

BACKGROUND

Bone readiness for implant placement is typically evaluated by bone quality/density on 2-dimensional radiographs and cone beam computed tomography at an arbitrary time between 3 and 6 months after tooth extraction and alveolar ridge preservation (ARP). The aim of this study is to investigate if high-frequency ultrasound (US) can classify bone readiness in humans, using micro-CT as a reference standard to obtain bone mineral density (BMD) and bone volume fraction (BVTV) of healed sockets receiving ARP in humans.

METHODS

A total of 27 bone cores were harvested during the implant surgery from 24 patients who received prior extraction with ARP. US images were taken immediately before the implant surgery at a site co-registered with the tissue biopsy collection location, made possible with a specially designed guide, and then classified into 3 tiers using B-mode image criteria (1) favorable, (2) questionable, and (3) unfavorable. Bone mineral density (hydroxyapatite) and BVTV were obtained from micro-CT as the gold standard.

RESULTS

Hydroxyapatite and BVTV were evaluated within the projected US slice plane and thresholded to favorable (>2200 mg/cm3; >0.45 mm3/mm3), questionable (1500-2200 mg/cm3; 0.4-0.45 mm3/mm3), and unfavorable (<1500 mg/cm3; <0.4 mm3/mm3). The present US B-mode classification inversely scales with BMD. Regression analysis showed a significant relation between US classification and BMD as well as BVTV. T-test analysis demonstrated a significant correlation between US reader scores and the gold standard. When comparing Tier 1 with the combination of Tier 2 and 3, US achieved a significant group differentiation relative to mean BMD (p = 0.004, true positive 66.7%, false positive 0%, true negative 100%, false negative 33.3%, specificity 100%, sensitivity 66.7%, receiver operating characteristics area under the curve 0.86). Similar results were found between US-derived tiers and BVTV.

CONCLUSION

Preliminary data suggest US could classify jawbone surface quality that correlates with BMD/BVTV and serve as the basis for future development of US-based socket healing evaluation after ARP.

Restoring Severely Atrophic Edentulous Ridge of Mandible Using Self-Expanding Tissue Expander-A Case Report

This report describes the use of Self Inflating Tissue Expanders (SITEs) to rehabilitate severely atrophic edentulous mandibular ridges, enabling successful bone grafting and implant placement. The treatment resulted in stable and complication-free implants over a seven-year follow-up, demonstrating SITEs' effectiveness in providing sufficient bone volume and soft tissue coverage for dental implants.

Unveiling the consequences of early human saliva contamination on membranes for guided bone regeneration

AIMS

GBR membranes have various surface properties designed to elicit positive responses in regenerative clinical procedures; dental clinicians attempt to employ techniques to prevent the direct interaction of contaminated oral fluids with these biomaterials. However, saliva is uninterruptedly exhibited in oral surgical procedures applying GBR membranes, suggesting a persistent interaction with biomaterials and the surrounding oral tissues. This fundamental study aimed to investigate potential alterations in the physical, chemical, and key biological properties of membranes for guided bone regeneration (GBR) caused by isolated early interaction with human saliva.

METHODS

A reproducible step-by-step protocol for collecting and interacting human saliva with membranes was developed. Subsequently, membranes were evaluated for their physicochemical properties, protein quantification, DNA, and 16S rRNA levels viability of two different cell lines at 1 and 7 days, and ALP activity. Non-interacted membranes and pure saliva of donors were applied as controls.

RESULTS

Qualitative morphological alterations were noticed; DNA extraction and 16S quantification revealed significantly higher values. Furthermore, the viability of HGF-1 and MC3T3-E1 cells was significantly (p < .05) reduced following saliva interaction with biodegradable membranes. Saliva contamination did not prejudice PTFE membranes significantly in any biological assay.

CONCLUSIONS

These outcomes demonstrated a susceptible response of biodegradable membranes to isolated early human saliva interaction, suggesting impairment of structural morphology, reduced viability to HGF-1 and MC3T3-E1, and higher absorption/adherence of DNA/16S rRNA. As a result, clinical oral procedures may need corresponding refinements.

Advancements in alveolar bone grafting and ridge preservation: a narrative review on materials, techniques, and clinical outcomes

This narrative review systematically explores the progression of materials and techniques in alveolar ridge preservation (ARP). We commence by delineating the evolution from traditional ARP methods to cutting-edge alternatives, including platelet-rich fibrin, injectable bone repair materials, and hydrogel systems. Critical examination of various studies reveals these innovative approaches not only accelerate bone healing but also significantly improve patient-reported outcomes, such as satisfaction, pain perception, and overall quality of life. Emphasis is placed on the correlation between advanced ARP techniques and enhanced patient comfort and clinical efficacy, underscoring their transformative potential in dental implantology. Highlighting the effectiveness of ARP, the implant survival rate over a span of 5 to 7 years was high, showcasing the reliability and success of these methods. Further, patients expressed high aesthetic satisfaction with the soft tissue outcome, evidenced by an average visual analog scale (VAS) score of 94. This positive aesthetic appraisal is linked to the clinical health of implants, potentially due to the employment of tooth-supported surgical guides. The economic analysis reveals a varied cost range for bone graft substitutes ($46.2 to $140) and socket sealing materials ($12 to $189), with a noteworthy correlation between the investment in barrier membranes and the diminished horizontal and vertical ridge resorption. This suggests that membrane usage significantly contributes to preserving ridge dimensions, offering a cost-effective strategy for enhancing ARP outcomes. In conclusion, this review illuminates the significant advancements in ARP, highlighting the shift towards innovative materials and techniques that not only promise enhanced bone regeneration and reduced healing times but also improve patient satisfaction and aesthetic outcomes. The documented high implant survival rate and the beneficial economic implications of membrane use further validate the effectiveness of contemporary ARP strategies, paving the way for their broader adoption in dental implantology.

Horizontal ridge augmentation using guided bone regeneration with an association of particulate allografts mixed with platelet-rich fibrin, collagen membrane and tent-screws: A prospective study

BACKGROUND

Guided Bone Regeneration (GBR) is a versatile technique employed not only to correct pre-implant alveolar bone defects but also to facilitate bone defect correction during simultaneous implant placement. The effectiveness of GBR varies significantly among different protocols, as reported in the literature. This study specifically aimed to radiologically evaluate the horizontal bone gain obtained using a GBR procedure combining a particulate allograft, platelet-rich fibrin, resorbable collagen membrane, and screw tents.

MATERIALS AND METHODS

A total of 42 patients with an insufficient alveolar bone width for dental implant placement were treated with a GBR technique using a mixture of particulate allograft (demineralised freeze-dried bone allograft 300-500 and 500-1000 µm), advanced platelet-rich fibrin (A-PRF), resorbable collagen membranes and screws tents (1.2 mm in diameter). Over the course of the study, a total of 63 GBR procedures were performed on these patients. Bone gains were measured by cone-beam computed tomography at 9.1 ± 2.0 months post-operative.

RESULTS

A significant mean increase (P < 0.001) of 3.2 ± 0.9 mm at the sites of the greatest bone defect was observed. This improvement was consistent across various locations, including both maxillary and mandibular regions, and in cases of terminal and embedded edentulism, without any post-operative complications during the entire post-operative follow-up. All patients benefited from implant placement following the bone augmentation protocol.

CONCLUSION

GBR combining particulate allografts, A-PRF, collagen membranes, and screw tents achieves reliable, predictable, and reproducible clinical gains that allow for future implant placement.

Assessment of bone regeneration after maxillary radicular cyst enucleation with or without bone grafting materials: a retrospective cohort study

OBJECTIVE

The limitations of spontaneous bone healing underscore the necessity for exploring alternative strategies to enhance bone regeneration in maxillary radicular cyst cases. This retrospective study aimed to assess the impact of a bone substitute material (i.e., Bio-Oss) on bone volume regeneration following maxillary radicular cyst enucleation using cone-beam computed tomography (CBCT).

MATERIALS AND METHODS

Seventy-three patients with maxillary radicular cysts were divided into two groups: one undergoing guided bone regeneration (GBR) with Bio-Oss and absorbable collagen membrane (n = 35), and the other receiving cyst excision alone (n = 38). Volumetric measurements using Amira software on CBCT scans evaluated bone regeneration, with cystic lesion shrinkage rates calculated. Intergroup comparisons utilized independent sample t-tests (P < 0.05), and linear regression analysis assessed the influence of preoperative cyst volume and group on bone healing.

RESULTS

Both groups showed similar success rates in bone formation at the 12-month follow-up, with no significant differences between them (mean (SD), control: 75.16 (19.17) vs. GBR: 82 (20.22), P > 0.05). Linear regression analysis revealed a negative correlation between preoperative cyst volume and bone regeneration in both groups (P < 0.05).

CONCLUSION

Bio-Oss may not significantly enhance bone augmentation in maxillary radicular cysts. In addition, preoperative cyst volume negatively affected the shrinkage rate of cystic lesions.

CLINICAL RELEVANCE

Clinicians should consider patient-specific factors such as anatomy and lesion size when determining the need for bone substitute materials. Future research could focus on optimizing treatment protocols and alternative regenerative strategies to improve patient outcomes in maxillary cyst cases.

Ridge augmentation planning, wound healing evaluation, and peri-implant tissue phenotype assessment with ultrasonography: A case report

BACKGROUND

Ridge regeneration for implant therapy requires comprehensive site evaluation and wound healing monitoring. This case report aimed to demonstrate ultrasound (US) can image soft and hard tissues for surgical planning and assess longitudinal outcomes.

METHODS AND RESULTS

US was used in a patient planned for ridge augmentation to evaluate soft tissue thickness, location of muscle attachment, and hard tissue defect features presurgically. US were obtained at 1, 2.5, and 5 months afterward to assess tissue healing. Preoperatively, US showed ∼2.5 mm and ∼0.8 mm soft tissue thickness on the facial and lingual sides, respectively. The crestal bone width was ∼2 mm, with severe facial bone deficiency and high muscle attachment. US showed wound approximation and ridge width gain to 4.5 and 4.0 mm at 1 and 5 months, respectively. US tissue perfusion increased to ∼two-fold and ∼4-fold at 1 and 2.5 months and reduced below the baseline at 5 months. An implant with simultaneous bone augmentation was performed accordingly. Tissue phenotype around the implant was measured on US images at 1-year visit.

CONCLUSIONS

This case report demonstrated that US parameters could be valuable for planning and wound healing outcome assessment of ridge augmentation in clinical as well as research settings.

KEY POINTS

Why is this case new information? Novel high-resolution, chairside ultrasound was proposed to facilitate treatment planning and wound healing outcome assessment of ridge augmentation in clinical as well as research settings. What are the keys to successful use of this technology? Proper training in imaging acquisition and interpretation Adhere to high-level disinfection protocol Patient education and explanation What are the primary limitations to success in using this technology? Investment in this technology Learning curve in imaging acquisition and reading Insurance reimbursement strategy.

Antibacterial properties of marine algae incorporated polylactide acid membranes as an alternative to clinically applied different collagen membranes

The reconstruction of bony defects in the alveolar crest poses challenges in dental practice. Guided tissue regeneration (GTR) and guided bone regeneration (GBR) procedures utilize barriers to promote bone regeneration and prevent epithelial growth. This study focuses on evaluating the antibacterial properties of marine algae-polylactic acid (PLA) composite membranes compared to commercially available collagen membranes. Marine algae (Corallina elongata, Galaxaura oblongata, Cystoseira compressa, Saragassum vulgare, and Stypopodium schimperi) were processed into powders and blended with PLA to fabricate composite membranes. Cytocompatibility assays using human periodontal ligament fibroblasts (n = 3) were performed to evaluate biocompatibility. Antibacterial effects were assessed through colony-forming units (CFU) and scanning electron microscopy (SEM) analysis of bacterial colonization on the membranes. The cytocompatibility assays demonstrated suitable biocompatibility of all marine algae-PLA composite membranes with human periodontal ligament fibroblasts. Antibacterial assessment revealed that Sargassum vulgare-PLA membranes exhibited the highest resistance to bacterial colonization, followed by Galaxaura oblongata-PLA and Cystoseira compressa-PLA membranes. SEM analysis confirmed these findings and revealed smooth surface textures for the marine algae-PLA membranes compared to the fibrous and porous structures of collagen membranes. Marine algae-PLA composite membranes show promising antibacterial properties and cytocompatibility for guided bone and tissue regeneration applications. Sargassum vulgare-PLA membranes demonstrated the highest resistance against bacterial colonization. These findings suggest that marine algae-PLA composite membranes could serve as effective biomaterials for infection control and tissue regeneration. Further in vivo validation and investigation of biodegradation properties are necessary to explore their clinical potential.

A bi-layered asymmetric membrane loaded with demineralized dentin matrix for guided bone regeneration

OBJECTIVES

Guided bone regeneration (GBR) is a well-established method for repairing hard tissue deficiency in reconstructive dentistry. The aim of this study was to investigate the barrier function, osteogenic activity and immunomodulatory ability of a novel bi-layered asymmetric membrane loaded with demineralized dentin matrix (DDM).

METHODS

DDM particles were harvested from healthy, caries-free permanent teeth. Electrospinning technique was utilized to prepare bi-layered DDM-loaded poly(lactic-co-glycolic acid) (PLGA)/poly(lactic acid) (PLA) membranes (abbreviated as DPP bilayer membranes). We analyzed the membranes' surface properties, cytocompatibility and barrier function, and evaluated their osteogenic activity in vitro. In addition, its effects on the osteogenic immune microenvironment were also investigated.

RESULTS

Synthetic DPP bilayer membranes presented suitable surface characteristics and satisfactory cytocompatibility. Transwell assays showed significant fewer migrated cells by the DPP bilayer membranes compared with blank control, with or without in vitro degradation (all P < 0.001). In vitro experiments indicated that our product elevated messenger ribonucleic acid (mRNA) expression levels of osteogenic genes alkaline phosphatase (ALP), osteopontin (OPN), osteocalcin (OCN) and runt-related transcription factor 2 (Runx2). Among all groups, 20% DPP bilayer membrane displayed highest ALP activity (P < 0.001). Furthermore, DPP bilayer membranes enhanced the mRNA expression of M2 macrophage markers and increased the proportion of CD206+ M2 macrophages by 100% (20% DPP: P < 0.001; 30% DPP: P < 0.001; 40% DPP: P < 0.05), thus exerting an inflammation suppressive effect.

CONCLUSIONS

DPP bilayer membranes exhibited notable biological safety and osteogenic activity in vitro, and have potential as a prospective candidate for GBR approach in the future.

Application of CAD-CAM Technologies for Maxillofacial Bone Regeneration: A Narrative Review of the Clinical Studies

The application of regenerative methods in treating maxillofacial defects can be categorized as functional bone regeneration in which scaffolds without protection are used and in-situ bone regeneration in which a protected healing space is created to induce bone formation. It has been shown that functional bone regeneration can reduce surgical time and obviate the necessity of autogenous bone grafting. However, studies mainly focused on applying this method to reconstruct minor bone effects, and more investigation concerning the large defects is required. In terms of in situ maxillofacial bone regeneration with the help of CAD-CAM technologies, the present data have suggested feasible mesh rigidity, perseverance of the underlying space, and apt augmentative results with CAD-CAM-based individualized Ti meshes. However, complications, including dehiscence and mesh exposure, coupled with consequent graft loss, infection and impeded regenerative rates have also been reported.

Harmonizing Thickness and Permeability in Bone Tissue Engineering: A Novel Silk Fibroin Membrane Inspired by Spider Silk Dynamics

Guided bone regeneration gathers significant interest in the realm of bone tissue engineering; however, the interplay between membrane thickness and permeability continues to pose a challenge that can be addressed by the water-collecting mechanism of spider silk, where water droplets efficiently move from smooth filaments to rough conical nodules. Inspired by the natural design of spider silk, an innovative silk fibroin membrane is developed featuring directional fluid transportation via harmoniously integrating a smooth, dense layer with a rough, loose layer; conical microchannels are engineered in the smooth and compact layer. Consequently, double-layered membranes with cone-shaped microporous passageways (CSMP-DSF membrane) are designed for in situ bone repair. Through extensive in vitro testing, it is noted that the CSMP-DSF membrane guides liquid flow from the compact layer's surface to the loose layer, enabling rapid diffusion. Remarkably, the CSMP-DSF membrane demonstrates superior mechanical properties and resistance to bacterial adhesion. When applied in vivo, the CSMP-DSF membrane achieves results on par with the commercial Bio-Gide collagen membranes. This innovative integration of a cross-thickness wetting gradient structure offers a novel solution, harmonizing the often-conflicting requirements of material transport, mechanical strength, and barrier effectiveness, while also addressing issues related to tissue engineering scaffold perfusion.

Management of postoperative outcomes of polytetrafluoroethylene membranes in alveolar ridge reconstruction: a systematic review

Guided bone regeneration (GBR) is a validated technique with satisfactory outcomes during 30 years of follow-up. The use of polytetrafluoroethylene (PTFE) membrane for vertical augmentation has been studied extensively. However, studies have reported exposure rates of up to 31%, there is no consensus on the management of postoperative exposure. The objective of this study was to propose a management approach for postoperative exposure of polytetrafluoroethylene (PTFE) membranes in alveolar ridge reconstruction.

MATERIAL AND METHOD

An electronic search in PubMed Central's and additional electronic databases was performed. The search strategy was limited to human studies, full-text English or French articles published from 1990 until april 2023. The extracted data included defect location, membrane type, biomaterials, time to postoperative exposure, and Fontana classification stage. Protocol bias assessment was performed using an adaptation of the QUADAS-2 tool. This review has been registered on PROSPERO (ID: CRD42023445497).

RESULTS

A total of 43 articles were found to be eligible, and 11 of these met the predefined inclusion and exclusion criteria. Based on the results of this systematic review, an algorithm for the management of PTFE membrane exposure is proposed.

CONCLUSION

Postoperative membrane exposure is not a determining factor for the success of bone grafting. In cases with postoperative complications, the majority of cases still achieved adequate implant-prosthetic rehabilitation. Lastly, this series of 11 articles was insufficient to draw conclusions regarding good practice recommendations. A larger series is required to validate the specific management approaches.

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.

Efficacy of biomaterials for lateral bone augmentation performed with guided bone regeneration. A network meta-analysis

Bone regeneration is often required concomitant with implant placement to treat a bone fenestration, a dehiscence, and for contouring. This systematic review assessed the impact of different biomaterials employed for guided bone regeneration (GBR) simultaneous to implant placement on the stability of radiographic peri-implant bone levels at ≥12 months of follow-up (focused question 1), as well as on bone defect dimension (width/height) changes at re-assessment after ≥4 months (focused question 2). Only randomized controlled trials (RCTs) and controlled clinical trials (CCTs) that compared different biomaterials for GBR were considered. A Bayesian network meta-analysis (NMA) was performed using a random-effects model. A ranking probability between treatments was obtained, as well as an estimation of the surface under the cumulative ranking value (SUCRA). Overall, whenever the biological principle of GBR was followed, regeneration occurred in a predictable way, irrespective of the type of biomaterial used. A lower efficacy of GBR treatments was suggested for initially large defects, despite the trend did not reach statistical significance. Regardless of the biomaterial employed, a certain resorption of the augmented bone was observed overtime. While GBR was shown to be a safe and predictable treatment, several complications (including exposure, infection, and soft tissue dehiscence) were reported, which tend to be higher when using cross-linked collagen membranes.

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.

The importance of soft tissue condition in bone regenerative procedures to ensure long-term peri-implant health

Bone regenerative procedures have been widely proved to be a reliable treatment option to re-create the ideal pre-implant clinical conditions. Nevertheless, these techniques are not free from post-operative complications which might result in implant failure. Consequently, as demonstrated by the increasing recently published evidence, a careful pre- and intra-operative flap evaluation to ensure an ideal and hermetic tension-free wound closure is of paramount importance to successfully treat bony defects. In this respect, several surgical interventions mainly aimed to increase the amount of keratinized mucosa either to allow an optimal healing after a reconstructive procedure or to establish an optimal peri-implant soft tissue seal have been proposed. The present review summarizes the level of evidence on the surgical clinical aspects which have an impact on the soft tissue handling associated with bone reconstructive procedures and on the importance of soft tissue conditions to enhance and maintain peri-implant health in the long-term.

Egg white-derived peptide KPHAEVVLR promotes wound healing in rat palatal mucosa via PI3K/AKT/mTOR pathway

KPHAEVVLR (KR-9) is a peptide derived from egg white hydrolyzed, which has been found to accelerate skin wound healing in mice. However, the effect of KR-9 on wound healing on palatal mucosa in rats remains unknown, and the mechanism through which KR-9 promotes wound healing should be further explored. Herein, we aimed to investigate the effect and mechanism of KR-9 peptide on palatal mucosa wound healing. Our results showed that KR-9 reduced the wound area of palatal mucosa in rats and promoted human gingival fibroblasts(HGFs) migration and proliferation.The peptide can enter into cytoplasm. It also increased the phosphorylation of PI3K, AKT, and mTOR protein. The effect of KR-9 on HGFs migration and proliferation could be reversed by PI3K inhibitor. These results demonstrated that KR-9 peptide facilitated wound healing of palatal mucosa in rats by promoting HGFs migration and proliferation, which was mediated by PI3K/AKT/mTOR signaling pathway. This data proves that KR-9 might be used as a potential agent for wound healing treatment.

Bone regeneration in implant dentistry: Which are the factors affecting the clinical outcome?

The key factors that are needed for bone regeneration to take place include cells (osteoprogenitor and immune-inflammatory cells), a scaffold (blood clot) that facilitates the deposition of the bone matrix, signaling molecules, blood supply, and mechanical stability. However, even when these principles are met, the overall amount of regenerated bone, its stability over time and the incidence of complications may significantly vary. This manuscript provides a critical review on the main local and systemic factors that may have an impact on bone regeneration, trying to focus, whenever possible, on bone regeneration simultaneous to implant placement to treat bone dehiscence/fenestration defects or for bone contouring. In the future, it is likely that bone tissue engineering will change our approach to bone regeneration in implant dentistry by replacing the current biomaterials with osteoinductive scaffolds combined with cells and mechanical/soluble factors and by employing immunomodulatory materials that can both modulate the immune response and control other bone regeneration processes such as osteogenesis, osteoclastogenesis, or inflammation. However, there are currently important knowledge gaps on the biology of osseous formation and on the factors that can influence it that require further investigation. It is recommended that future studies should combine traditional clinical and radiographic assessments with non-invasive imaging and with patient-reported outcome measures. We also envisage that the integration of multi-omics approaches will help uncover the mechanisms responsible for the variability in regenerative outcomes observed in clinical practice.

Bone grafting techniques and materials for implant dentistry

Bone quality, volume, height and width all play a pivotal role in dental implant stability, success and survival. A lack of adequate bone can be overcome with various bone grafting procedures. Dependent on many factors, including the amount of bone required, the site of implant placement, patient preferences and clinician factors; the type of bone grafting material and procedure undertaken can vary. Supplemental bone can be sourced from a variety of sources, including autogenous, allogenous and xenograft bone. Dependent on the source of the bone, it will have different properties in aiding bone formation, as well as being presented in different formulations, such as bone particles or bone blocks.The aim of this paper is to provide an overview of bone grafting indications, materials and types of bone grafting techniques that can be utilised to aid dental implant provision. It also discusses the properties needed to ensure optimal success of guided bone regeneration techniques.

Decontaminative Properties of Cold Atmospheric Plasma Treatment on Collagen Membranes Used for Guided Bone Regeneration

Background cold atmospheric plasma (CAP) is known to be a surface-friendly yet antimicrobial and activating process for surfaces such as titanium. The aim of the present study was to describe the decontaminating effects of CAP on contaminated collagen membranes and their influence on the properties of this biomaterial in vitro. Material and Methods: A total of n = 18 Bio-Gide^® (Geistlich Biomaterials, Baden-Baden, Germany) membranes were examined. The intervention group was divided as follows: n = 6 membranes were treated for one minute, and n = 6 membranes were treated for five minutes with CAP using kINPen^® MED (neoplas tools GmbH, Greifswald, Germany) with an output of 5 W, respectively. A non-CAP-treated group (n = 6) served as the control. The topographic alterations were evaluated via X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Afterward, the samples were contaminated with E. faecalis for 6 days, and colony-forming unit (CFU) counts and additional SEM analyses were performed. The CFUs increased with CAP treatment time in our analyses, but SEM showed that the surface of the membranes was essentially free from bacteria. However, the deeper layers showed remaining microbial conglomerates. Furthermore, we showed, via XPS analysis, that increasing the CAP time significantly enhances the carbon (carbonyl group) concentration, which also correlates negatively with the decontaminating effects of CAP. Conclusions: Reactive carbonyl groups offer a potential mechanism for inhibiting the growth of E. faecalis on collagen membranes after cold atmospheric plasma treatment.

Clinical Evaluation of Short (6 mm) and Longer Implants Placed Side by Side in Posterior Partially Edentulous Area: A 3-Year Observational Study

Background

Short implants have been proposed as an alternative solution for the rehabilitation of atrophic posterior region.

Purpose

To compare the clinical outcomes between 6 mm short implants and conventional implants placed under similar conditions of bone quality and occlusal loading.

Materials and Methods

Nine patients received atone 6 mm implant and one standard-length (8 mm length or longer) implants in a total of 10 partially edentulous areas. Implants were left submerged for 3-6 months healing period and the screw-retained splinted prostheses were delivered. When the provisional or final restoration was placed, and at each year after loading, standardized intraoral radiograph was taken for themarginal bone level (MBL) changes around the implants. Subsequently, the patients were recalled for the clinical examination evaluating the implant survival, sulcus bleeding index, suppuration, and the incidence of prosthetic complications at every 6 months after the definitive crown delivery. The observation period was continued to 3 years (mean follow-up was 3.4 ± 0.3 years) after functional loading.

Results

Nine patients (10 short implants and 10 standard length implants) were selected in this study. Cumulative survival rates of the short implants and standard-length implants were 100% in both groups, and no biological and prosthetic complication were found in 3 years observation period. Cortical bone thickness of implant insertion sites was 1.39 ± 0.45 mm at short implants and 1.38 ± 0.69 mm at standard-length implants, and trabecular bone computed tomography values of implant insertion sites was 424.1 ± 290.1 at short implants and 410.9 ± 267.9 at standard-length implants. The MBL changes were -0.30 ± 0.71 mm at short implants and -0.19 ± 0.78 mm at standard-length implants at 3 years follow-up visit. No significant difference was found in the average of MBL changes between implant length.

Conclusions

Within the limits of this study, it can be concluded that 6 mm short implants in a posterior edentulous region showed excellent results compared with conventional implants.

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.

Vertical augmentation of a severely atrophied posterior mandibular alveolar ridge for a dental implant using a patient-specific 3D printed PCL/BGS7 scaffold: A technical note

Vertical bone augmentation for dental implants in the posterior mandibular region with significant bone resorption is challenging. For this purpose, methods such as block bone grafting with screw fixation, particulate bone grafting with titanium mesh or barrier membrane, and distraction osteogenesis have been used, and autogenous block bone grafting is considered the gold standard. However, the autogenous block bone grafting has the following disadvantages: bone harvesting is challenging, and block bone contouring according to the recipient site is time-consuming and laborious. Therefore, in this study, we report the use of particulate bone with a polycaprolactone/bioactive glass-7 scaffold, designed, and three-dimensionally printed preoperatively, to resolve the above-mentioned challenges.

Influence of partially exposed nonabsorbable membrane for alveolar ridge preservation: A randomized controlled trial

AIM

This randomized controlled trial evaluated the impact of a partially exposed non-absorbable membrane (dPTFE) in Alveolar Ridge Preservation (ARP) procedures on clinical, tomographic, immunoenzymatic, implant-related, and patient-centered outcomes.

MATERIALS AND METHODS

Patients with a hopeless maxillary single-rooted tooth demanding rehabilitation with implants were included. Patients were randomized into two groups: dPTFE (n = 22)-tooth extraction followed by ARP using a partially exposed dPTFE membrane; USH (n = 22)-unassisted socket healing. Clinical and tomographic analyses were performed at baseline and after 3 months. After 3 months, patients received one dental implant. Implant stability quotient was obtained following implant placement. Bone-related markers were analyzed in bone biopsies using an immunoenzymatic assay.

RESULTS

Greater gain in Keratinized Mucosa Width (KMW) was observed in the dPTFE (1.33 ± 0.98 mm) compared to USH (0.59 ± 0.98 mm) (Mann-Whitney test, Z = 2,28, p < 0.05). USH showed a reduction of pain/discomfort, edema, and interference with daily life from the seventh day (Friedman/Wilcoxon test, maxT = 7.48, 8.00, and 5.92, respectively, p < 0.05). dPTFE presents a reduction of edema and interference with daily life from the 7th day and pain/discomfort from the 14th day (Friedman/Wilcoxon test, maxT = 5.40, 5.26, and 4.78, respectively, p < 0.05). The dPTFE group presented higher pain/discomfort in the 35 and 42 days and higher edema from 7 to 42 days postoperatively than USH group (Mann-Whitney test, p < 0.05). No differences between groups were observed in the tomographic measures, immunoenzymatic analysis, and implant stability (p > 0.05).

CONCLUSION

dPTFE was superior to USH by increasing KMW gain. However, dPTFE without bone graft presented similar bone loss compared to USH. This clinical trial was not registered prior to participant recruitment and randomization (NCT04329351).

Optimizing the combined soft tissue repair and osteogenesis using double surfaces of crosslinked collagen scaffolds

Excessive tissue damage or loss has been solved by guided tissue regeneration and guided bone regeneration theories. However, the unfavorable degradation property of the resorbable collagen scaffold brings a big challenge to support soft tissue stabilization and time-consuming osteogenesis. The combined effect for soft tissue and bone of the collagen scaffold with better degradation pattern has not been clearly proven. This study determined whether the double surfaces of crosslinked collagen scaffolds could optimize the combined soft tissue repair and osteogenesis. In this study, we applied the chemically crosslinking treatment to the commercially available collagen scaffolds. Surface characterization, mechanical property and cell proliferation in vitro were evaluated. Combined bilateral skin and bone defects were established with the smooth surface of scaffold facing the skin defect and the rough surface facing the bone defect on the calvaria of rat. Micro-CT and histological evaluation were applied to determine the scaffold degradation pattern, soft tissue repair and osteogenesis. The crosslinked collagen scaffolds showed comparably favorable surface porosity, structure intactness, superhydrophilicity and mechanical properties. Compared to the native scaffolds, the crosslinked scaffolds could optimize the combined soft tissue repair and osteogenesis by preferably prolonged degradation time. Early pro-angiogenesis facilitated soft tissue repair and osteogenesis by upregulated soft tissue matrix degradation and balanced pro-osteogenesis with limited osteoclast-mediated bone resorption. Taken together, this study offers a promising repair strategy for the combined soft tissue and bone defects. Further, the possible mechanism of controllable scaffold degradation should be conducted.

A minimally invasive method for titanium mesh fixation with resorbable sutures in guided bone regeneration: A retrospective study

OBJECTIVES

Titanium mesh has become a mainstream choice for guided bone regeneration (GBR) owing to its excellent space maintenance. However, the traditional fixation method using titanium screws impacts surgery efficiency and increases patient trauma. We report a novel method of fixing a titanium mesh using resorbable sutures. We assessed the feasibility of resorbable sutures for fixing a titanium mesh and whether it can serve as a stable, universal, and minimally invasive fixation method for a broader application of titanium meshes.

METHODS

Patients undergoing GBR with a digital titanium mesh fixed using titanium screws (TS group) and resorbable sutures (RS group) were observed at different time points. The stability of the fixation methods was evaluated on parameters such as titanium mesh spatial displacement, bone augmentation, and bone resorption.

RESULTS

A total of 36 patients were included in this study. The exposure rate of the titanium mesh in the TS group was 16.67%, while no exposure was noted in the RS group. There was no significant difference in the parameters of titanium mesh spatial displacement, bone augmentation, and bone resorption between the two groups (p > 0.05).

CONCLUSION

The use of resorbable sutures for fixing a titanium mesh can achieve similar results to traditional fixation using titanium screws. Although this new fixation method can improve the efficiency of the surgery and reduce the risk of complications, the long-term clinical effects require further follow-up investigation.

Surface characteristics and in vitro biocompatibility of surface-modified titanium foils as a regenerative barrier membrane for guided bone regeneration

This study evaluated surface characteristics and biocompatibility of surface-modified thin titanium (Ti) foils as a regenerative barrier membrane for future application in guided bone regeneration (GBR) surgery to augment atrophic alveolar bone. Anodic oxidation and post-heat treatment were performed to prepare various Ti foil samples. Then, the in vitro soft and hard tissue compatibility of the samples was evaluated by examining the cell responses using primary human gingival fibroblasts (HGFs) and MG63 human osteoblast-like cells. Investigated Ti foil samples showed marked differences in physicochemical surface properties. Additional 400°C heat treatment applied to the anodized Ti surface led to formation of an anatase titanium dioxide structure and well-organized nanoscale protrusions, and significantly increased surface wettability. Anodization and heat treatment enhanced the growth of HGFs and MG63 cells in Ti foil samples. Additional heat treatment for 10 and 30 min further significantly improved the response of HGFs including spreading and proliferation, and upregulated the mRNA expression of cell adhesion- and maturation-related genes as well as the osteoblast differentiation of MG63 cells. Ti foil sample with thin oxide coating obtained by a 30 min heat treatment exhibited poor clinical plasticity as a regenerative barrier membrane, which showed complete coating failure in the bending test. Our results indicate that anatase Ti oxide coating of a specific film thickness with nanoscale surface protrusion morphology and hydrophilic characteristics obtained by anodization and post-heat treatment would be an effective approach as a biocompatible Ti regenerative membrane for inducing better regeneration of both gingival tissue and bone.

SIS membrane modification to improve antimicrobial and osteogenic properties for guide bone regeneration

The guided bone regeneration (GBR) technique is the most common and durable approach to repairing bone defects in periodontal surgery. However, membrane exposure causes bacterial infiltration, which lowers the functional integrity of the barrier membrane and destroys bone repair. Here, an antibacterial peptide-modified small intestinal submucosa (SIS) membrane is used as a new GBR membrane for effective bone regeneration. The peptide JH8194 was placed into chitosan microspheres to preserve its stability and allow for sustained release, which realizes rapid and efficient functional modification of the SIS membrane. Biocompatibility and certain antibacterial activities were found in the modified SIS membrane (SIS@CS-JH8194). Additionally, in vitro experiments showed that SIS@CS-JH8194 promoted the expression of osteogenic-related factors and decreased the secretion of inflammatory factors in rat bone mesenchymal stem cells. In vivo experiments showed that SIS@CS-JH8194 could effectively promote bone regeneration in rat skull defects. In this work, we created a new antibacterial GBR membrane to help avoid postoperative infection and improve bone tissue regeneration.

Polycaprolactone versus collagen membrane and 1‐year clinical outcomes: A randomized controlled trial

BACKGROUND

Polycaprolactone (PCL) is a synthetic aliphatic polyester widely used in biomedical applications with biodegradability in the body and promotes cell proliferation and differentiation. A newly developed bilayered PCL membrane was developed for possibly being used as a membrane in guided bone regeneration (GBR).

PURPOSE

To compare the clinical efficacy between a newly developed bilayered PCL membrane with a Cytoplast™ RTM collagen membrane for GBR with simultaneous implant placement.

MATERIALS AND METHODS

Twenty-four patients were randomized to PCL or RTM group, and a total of 24 dental implants were placed. Primary outcomes were patient mean buccal bone thickness (BBT) immediately postimplantation and at 6 months using cone-beam CT and soft tissue surface dimensional changes (STC) at crown insertion, 6 months, and 1 year after loading using intraoral scanner. Secondary outcomes included success rate, clinical parameters, healing index, implant stability, pink esthetic score, and marginal bone levels.

RESULTS

The percentage of reduced BBT at 6 months was 32.38%, 25.94%, and 23.96% in the test group and 34.42%, 14.75%, and 6.34% in the control group at the corresponding levels. The mean difference of changed BBT associated with PCL membrane, when compared to collagen membrane, at 6 months was -0.02 ± 0.18 mm (95% confidence interval [CI]: -0.40 to 0.35), 0.29 ± 0.28 mm (95% CI: -0.29 to 0.87), and 0.62 ± 0.38 mm (95% CI: -0.17 to 1.42) at 0, 2, and 4 mm from implant shoulder. Minimal loss of STC was observed in both groups up to 1 year of loading. The mean difference loss of surface dimensional change associated with PCL membrane, when compared to collagen membrane, at 1 year of loading was 0.31 ± 0.19 mm (95% CI: -0.07 to 0.70), 0.22 ± 0.26 mm (95% CI: -0.33 to 0.76), and 0.17 ± 0.30 mm (95% CI: -0.45 to 0.78) at 0, 2, and 4 mm from implant shoulder. None of these differences were statistically significant (unpaired t-test, degrees of freedom [df] = 22; p > 0.05).

CONCLUSION

Within the limits of this trial, both barrier membranes resulted in comparable outcomes for GBR with implant placement after 1 year in function. Further research is necessary with a larger sample size.

Primary flap closure in alveolar ridge preservation for periodontally damaged extraction socket: A randomized clinical trial

INTRODUCTION

The effect of primary wound closure (PC) on alveolar ridge preservation (ARP) in periodontally damaged sockets has yet to be fully discovered.

METHODS

Periodontally damaged sockets were allocated to one of the following groups: (1) ARP with PC (group PC), and (2) ARP without PC (group secondary wound closure [SC]). Following tooth extraction and flap elevation, granule-type xenogeneic bone substitute material and a collagen barrier were applied. Ridge change was evaluated using cone-beam computed tomographic (CBCT) scans immediately after ARP and at 4 months. Core biopsy specimens were examined histomorphometrically.

RESULTS

A total of 28 patients were included in the analysis (13 in group PC, 15 in group SC). Histomorphometrically, the percentage of newly formed bone was 26.2 ± 17.7% and 24.6 ± 18.4% in groups PC and SC, respectively (independent t-test, degree of freedom [df] = 25, p > 0.05). Horizontal ridge changes on CBCT were -4.9 ± 3.1 mm and - 4.2 ± 2.5 mm in groups PC and SC at the 1 mm level below the ridge crest, respectively (independent t-test, df = 26, p > 0.05). Approximately half of the sites required additional bone augmentation at implant placement.

CONCLUSIONS

ARP with/without PC yielded similar new bone formation and radiographic ridge change. This clinical trial was not registered prior to participant recruitment and randomization (https://cris.nih.go.kr/cris/search/detailSearch.do/19718).

The use of periodontal membranes in the field of periodontology: spotlight on collagen membranes

Periodontal regenerative techniques are performed to accomplish the restitution of soft and hard teeth-supporting tissues that have been lost due to trauma or inflammatory disease. Periodontal membranes are used for these techniques to provide support and a framework for cell growth and tissue regeneration. They act as a temporary and selective barrier to cell proliferation. Easy clinical handling, biomechanical specifications, high biocompatibility, cell-occlusivity, and satisfactory bioresorption rate are essential properties a membrane needs to be effective. The creation and maintenance of a secluded space is also a fundamental rule in periodontal regenerative techniques. The use of barrier membranes in the field of restorative dentistry has progressed toward the use of minimally invasive approaches optimizing wound closure and limiting patient morbidity. This review intends to provide an overview of the major cellular events in the surgical wound and membrane surface. It was also performed to assess, from literature data, the pertinence of using non-resorbable and resorbable membranes for this regenerative purpose. Special attention will be given to collagen membranes.

Barrier Membranes for Guided Bone Regeneration (GBR): A Focus on Recent Advances in Collagen Membranes

Guided bone regeneration (GBR) has become a clinically standard modality for the treatment of localized jawbone defects. Barrier membranes play an important role in this process by preventing soft tissue invasion outgoing from the mucosa and creating an underlying space to support bone growth. Different membrane types provide different biological mechanisms due to their different origins, preparation methods and structures. Among them, collagen membranes have attracted great interest due to their excellent biological properties and desired bone regeneration results to non-absorbable membranes even without a second surgery for removal. This work provides a comparative summary of common barrier membranes used in GBR, focusing on recent advances in collagen membranes and their biological mechanisms. In conclusion, the review article highlights the biological and regenerative properties of currently available barrier membranes with a particular focus on bioresorbable collagen-based materials. In addition, the advantages and disadvantages of these biomaterials are highlighted, and possible improvements for future material developments are summarized.

Reconstruction of vertical alveolar ridge deficiencies utilizing a high-density polytetrafluoroethylene membrane /clinical impact of flap dehiscence on treatment outcomes: case series/

Objectives

The aim of this study was to evaluate the effects of membrane exposure during vertical ridge augmentation (VRA) utilizing guided bone regeneration with a dense polytetrafluoroethylene (d-PTFE) membrane and a tent-pole space maintaining approach by registering radiographic volumetric, linear and morphological changes.

Methods

In 8 cases alveolar ridge defects were accessed utilizing a split-thickness flap design. Following flap elevation VRA was performed with tent-pole space maintaining approach utilizing the combination of a non-reinforced d-PTFE membrane and a composite graft (1:1 ratio of autogenous bone chips and bovine derived xenografts). Three-dimensional radiographic evaluation of hard tissue changes was carried out with the sequence of cone-beam computed tomography (CBCT) image segmentation, spatial registration and 3D subtraction analysis.

Results

Class I or class II membrane exposure was observed in four cases. Average hard tissue gain was found to be 0.70 cm3 ± 0.31 cm3 and 0.82 cm3 ± 0.40 cm3 with and without membrane exposure resulting in a 17% difference. Vertical hard tissue gain averaged 4.06 mm ± 0.56 mm and 3.55 mm ± 0.43 mm in case of submerged and open healing, respectively. Difference in this regard was 14% between the two groups. Horizontal ridge width at 9-month follow-up was 5.89 mm ± 0.51 mm and 5.61 mm ± 1.21 mm with and without a membrane exposure respectively, resulting in a 5% difference.

Conclusions

With the help of the currently reported 3D radiographic evaluation method, it can be concluded that exposure of the new-generation d-PTFE membrane had less negative impact on clinical results compared to literature data reporting on expanded polytetrafluoroethylene membranes.

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.

CBCT Evaluation of Sticky Bone in Horizontal Ridge Augmentation with and without Collagen Membrane-A Randomized Parallel Arm Clinical Trial

Guided bone regeneration (GBR) is a reliable technique used to treat ridge deficiencies prior or during implant placement. Injectable-platelet rich fibrin (i-PRF) laced with a bone substitute (sticky bone) has heralded the way for advancing the outcomes of bone regeneration. This study evaluated the efficacy of sticky bone in horizontal ridge augmentation with and without collagen membrane. A total of 20 partially edentulous patients (Group-I n = 10; Group-II n = 10) that indicated GBR were included, and the surgical procedure was carried out. In Group-I, the sticky bone and collagen membrane were placed in ridge-deficient sites and Group-II received only sticky bone. At the end of 6 months, 20 patients (Group-I (n = 10); Group-II (n = 10)) completed the follow-up period. A CBCT examination was performed to assess changes in the horizontal ridge width (HRW) and vertical bone height (VBH). A statistically significant increase in HRW (p < 0.05) was observed in both groups with mean gains of 1.35 mm, 1.55 mm, and 1.93 mm at three levels (crest, 3 mm, and 6 mm) in Group-I and 2.7 mm, 2.8 mm, and 2.6 mm at three levels in Group-II. The intergroup comparison revealed statistical significance (p < 0.05) with respect to HRW and KTW (Keratinised tissue width) gains of 0.775 at the 6-month follow-up. Sticky-bone (Xenogenic-bone graft + i-PRF) served as a promising biomaterial in achieving better horizontal bone width gain.

Flipped autograft: A novel approach for management of wound dehiscence in implant dentistry. A case report

Introduction and importance

This case report describes a novel technique for management of peri-implant wound dehiscence that involves using auto graft from the same surgical site to seal the dehiscence defect.

Case presentation

A 21-year-old female was referred for extraction of a non-restorable lower left first molar and replacement by immediate dental implant. Following attachment of the cover screw bone graft biomaterial and collagen membrane was secured over the biomaterial and buccal flap was coronally positioned and sutured. Patient was seen 1 week after surgery for follow up where a minor wound dehiscence was discovered with some biomaterial particles exposed. Patient was advised to continue strict oral hygiene control and to wait for another week. After 2 weeks of the implant placement surgery patient came back for dehiscence management visit where an innovative flipped autograft technique was performed to seal the dehiscence defect.

Clinical discussion

Healing by primary intention was achieved that led to uneventful healing and hence a successful well-functioning restoration with clinically healthy soft tissue and optimal aesthetic outcome.

Conclusions

Peri-implant wound dehiscence can be successfully treated by the novel flipped autograft technique that yielded great aesthetic and functional results.

•

This report is the first to demonstrate the management of wound dehiscence using flipped autograft technique

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Visibility and access, Primary closure with delicate manipulation and patient home care are the keys to successful management of this case.

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The primary limitations to success in this case are poor blood supply associated with thin thickness soft tissue flap and Failure to achieve primary closure

Bacterial Growth on Three Non-Resorbable Polytetrafluoroethylene (PTFE) Membranes-An In Vitro Study

GBR (Guided Bone Regeneration) procedure is challenged by the risk of membrane exposure to the oral cavity and contamination. The barrier quality of these membranes serve as a mechanical block from bacterial penetration into the GBR site. The purpose of this in vitro study was to evaluate the antibacterial effect of three commercial non-resorbable polytetrafluoroethylene membranes. (Two d-PTFE membranes and one double layer e-PTFE +d-PTFE membrane). A validated in vitro model with two bacterial species (Streptococcus sanguinis and Fusobacterium nucleatum) was used. Eight samples from membrane each were placed in a 96-well microtiter plate. The experimental and positive control groups were exposed to a bacterial suspension which involved one bacterial species in each plate. Bacterial growth was monitored spectrophotometrically at 650 nm for 24 h in temperature controlled microplate spectrophotometer under anaerobic conditions. One- Sample Kolmogorov−Smirnov Normal test and the Kruskal−Wallis test was used for the statistical analysis. As shown by the bacterial growth curves obtained from the spectrophotometer readings, all three membranes resulted in bacterial growth. We have not found a statistical difference in F. nucleatum growth between different membrane samples and the positive control group. However, S. sanguinis growth was reduced significantly in the presence of two membranes (CYTOPLAST TXT-200 and NeoGenTM) when compared to the control (p < 0.01). The presence of Permamem® had no significant influence on S. sanguinis growth. Some types of commercial non-resorbable PTFE membranes may have an impact on the growth dynamics of specific bacterial species.

Polymeric Nanotechnologies for the Treatment of Periodontitis: A Chronological Review

Periodontitis is a chronic infectious and inflammatory disease of periodontal tissues estimated to affect 70 - 80 % of all adults. At the same time, periodontium, the site of periodontal pathologies, is an extraordinarily complex plexus of soft and hard tissues, the regeneration of which using even the most advanced forms of tissue engineering continues to be a challenge. Nanotechnologies, meanwhile, have provided exquisite tools for producing biomaterials and pharmaceutical formulations capable of elevating the efficacies of standard pharmacotherapies and surgical approaches to whole new levels. A bibliographic analysis provided here demonstrates a continuously increasing research output of studies on the use of nanotechnologies in the management of periodontal disease, even when they are normalized to the total output of studies on periodontitis. The great majority of biomaterials used to tackle periodontitis, including those that pioneered this interesting field, have been polymeric. In this article, a chronological review of polymeric nanotechnologies for the treatment of periodontitis is provided, focusing on the major conceptual innovations since the late 1990s, when the first nanostructures for the treatment of periodontal diseases were fabricated. In the opening sections, the etiology and pathogenesis of periodontitis and the anatomical and histological characteristics of the periodontium are being described, along with the general clinical manifestations of the disease and the standard means of its therapy. The most prospective chemistries in the design of polymers for these applications are also elaborated. It is concluded that the amount of innovation in this field is on the rise, despite the fact that most studies are focused on the refinement of already established paradigms in tissue engineering rather than on the development of revolutionary new concepts.

Challenges and tissue engineering strategies of periodontal guided tissue regeneration

Periodontitis is a chronic infectious oral disease with a high prevalence rate in the world, and is a major cause of tooth loss. Nowadays, people have realized that the local microenvironment that includes proteins, cytokines, and extracellular matrix has a key influence on the functions of host immune cells and periodontal ligament stem cells during a chronic infectious disease such as periodontitis. The above pathological process of periodontitis will lead to a defect of periodontal tissues. Through the application of biomaterials, biological agents, and stem cells therapy, guided tissue regeneration (GTR) makes it possible to reconstruct healthy periodontal ligament tissue after local inflammation control. To date, substantial advances have been made in periodontal guided tissue regeneration. However, the process of periodontal remodeling experiences complex microenvironment changes, and currently periodontium regeneration still remains to be a challenging feat. In this review, we summarized the main challenges in each stage of periodontal regeneration, and try to put forward appropriate biomaterial treatment mechanisms or potential tissue engineering strategies that provide a theoretical basis for periodontal tissue engineering regeneration research.

The “Sling” Technique for Horizontal Guided Bone Regeneration: A Retrospective Case Series

The aim of this retrospective case series was to present a new technique, called the “sling technique”, for massive horizontal alveolar ridge augmentation through the innovative use of an expanded polytetrafluoroethylene (e-PTFE) membrane to reduce the risk of biological complications related to membrane exposure. Materials and Methods: Eligible patients for implant rehabilitation with a horizontal bone defect were enrolled in our study. All patients were treated with our new GBR approach, called the “sling technique” (ST), which consisted of covering the vestibular side of the bone defect with a stretched e-PTFE membrane. This technique allowed the amplification of the membrane surface as long as the compression and the immobilization of the underlying graft material remained (1:1 autologous bone and bovine xenograft). The membrane was placed far from the surgical incision of the mucosa to avoid infective complications. Pre- and post-regenerative surgery CBCT scans were used to assess the tissue gain amount after the GBR. Results: A total of 10 patients (4 females, 6 males; age range: 45–60 years old) were enrolled in our study and 33 implants were placed in regenerated bone. An average of 4 mm bone gain was achieved using the ST. No membrane exposures or biological complications were registered during the post-operative healing period. After a 24-month follow-up, a 100% implant survival rate was observed without hard or soft tissue dehiscence. Conclusion: The e-PTFE membrane positioned with the “sling technique” gave satisfactory results in horizontal bone augmentation. Considering the small sample, further confirmations with larger studies are needed.

Permeability of P. gingivalis or its metabolic products through collagen and dPTFE membranes and their effects on the viability of osteoblast-like cells: an in vitro study

Membrane exposure is a widely reported and relatively common complication in Guided Bone Regeneration (GBR) procedures. The introduction of micro-porous dPTFE barriers, which are impervious to bacterial cells, could reduce the technique sensitivity to membrane exposure, even if there are no studies investigating the potential passage of bacterial metabolites through the barrier. Aim of this study was the in vitro evaluation of the permeability of three different GBR membranes (dPTFE, native and cross-linked collagen membranes) to Porphyromonas gingivalis; in those cases, where bacterial penetration could not be observed, another purpose was the analysis of the viability and differentiation capability of an osteosarcoma (U2OS) cell line in presence of bacteria eluate obtained through membrane percolation. A system leading to the percolation of P. gingivalis broth culture through the experimental membranes was arranged to assess the permeability to bacteria after 24 and 72 h of incubation. The obtained solution was then added to U2OS cell cultures which underwent, after 10 days of incubation, MTT and red alizarin essays. The dPTFE membrane showed resistance to bacterial penetration, while both types of collagen membranes were crossed by P. gingivalis after 24 h. The bacteria eluate filtered through dPTFE membrane didn't show any toxicity on U2OS cells. Results of this study demonstrate that dPTFE membranes can contrast the penetration of both P. gingivalis and its metabolites toxic for osteoblast-like cells. The toxicity analysis was not possible for the collagen membranes, since permeability to bacterial cells was observed within the first period of incubation.

Complications in bone-grafting procedures: Classification and management

Bone-regenerative interventions aiming to restore deficient alveolar ridges, such as the use of block grafts or through the application of guided bone-regeneration principles, have reported positive outcomes in the published scientific literature. These interventions, however, are invasive, and hence, intraoperative and/or postoperative complications may occur. The types of complications and their severity may vary from the exposure of the biomaterial (membrane or graft) to postsurgical infections, neurosensorial disturbances, occurrence of hemorrhage, and pain, etc. The aim of the present narrative review was to search the available scientific evidence concerning the incidence of these complications, their effect on treatment outcomes, their clinical management and, finally, strategies aimed at prevention. Exposure of the barrier membrane or the block graft is the most common complication associated with oral regenerative interventions. To manage these complications, depending on the extent of the exposure and the presence or absence of concomitant infections, therapeutic measures may vary, from the topical application of antiseptics to the removal of the barrier membrane or the block graft. Regardless of their treatment, the occurrence of these complications has been associated with patient selection, with compliant patients (eg, nonsmokers) having a lower reported incidence of complications. Similarly, surgical factors such as correct flap elevation and a tensionless closure are of obvious importance. Finally, to prevent the incidence of complications, it appears prudent to utilize whenever possible less invasive surgical interventions.

Healing complications and their detrimental effects on bone gain in vertical-guided bone regeneration: A systematic review and meta-analysis

PURPOSE

Guided bone regeneration (GBR) utilizes a barrier membrane to allow osteogenic cells to populate a space by excluding epithelial and connective tissue cells. The purpose of this systematic review was to investigate the ratio of means (RoM) of vertical bone gained (Outcome) in vertical GBR procedures with healing complications (Intervention) and in vertical GBR procedures without healing complications (Comparison) in patients with vertically resorbed edentulous ridges that require dental implant placement (Population). A further aim was to investigate the incidence of complications after vertical GBR, and the influence of the timing of implant placement and regenerative devices on complications.

MATERIALS AND METHODS

MEDLINE (through PubMed), EMBASE, and Cochrane Central Register of Controlled Trials (CENTRAL) were searched in duplicate up to, and including, November 2020 for randomized and controlled clinical trials and prospective and retrospective case series. Outcomes included patient-level and site-level RoM of vertical bone gain between healing complications and uneventful healing, and incidences of complications that occurred after vertical GBR. Random-effects and fixed-effects meta-analyses were performed where appropriate. This study was registered on PROSPERO (CRD42021226432).

RESULTS

A total of 31 publications were selected for the qualitative and quantitative analyses. The RoM of vertical bone gained was 0.65 [95% CI = 0.47, 0.91] and 0.62 [95% CI = 0.45, 0.85] when membrane exposure without suppuration and abscess formation without membrane exposure occurred respectively, in comparison to uneventful healing. The overall incidence proportion of healing complications occurring at the augmented site at a site- and patient-level was 11.0% [95% CI = 7.0, 15.6] and 10.8% [95% CI = 6.6, 15.7]. At a patient-level, there were no significant differences between a simultaneous or staged approach, or with the regenerative device used. The site-level incidence proportion of membrane exposure without suppuration, membrane exposure with suppuration, and with abscess formation without membrane exposure was 8.7% [95% CI = 4.2, 14.2], 0.7% [95% CI = 0.0, 2.9], and 0.5% [95% CI = 0.0, 1.7], respectively. The site-level weighted mean incidence proportion of neurologic complications occurring at the donor site was 0.8% [95% CI = 0.0, 5.3].

CONCLUSIONS

There is a significant reduction in bone gain when healing complications occur. However, healing complications are relatively uncommon surgical complications after vertical GBR.