The response of human osteoblasts on bovine xenografts with and without hyaluronate used in bone augmentation.

The aim of the in vitro study was to asses the effect of hyaluronate in conjunction with bovine derived xenografts on the viability, proliferation on day 4, 7 and 10, expression of early osteogenic differentiation marker Alkaline phosphatase on day 14 and 21, collagen, calcium deposition on day 14, 21 and 28 and cellular characteristics, as assessed through live cell image analysis, confocal laser scanning microscopy and scanning electron microscopy, in primary human osteoblasts compared to three bovine xenografts without hyaluronate. All experiments were performed in triplicates. Data were compared between groups and timepoints using one-way analysis of variance (ANOVA). Bonferroni post hoc test were further used for multiple comparison between groups (p < .05) An increase in cell viability (p < .05) and enhanced ALP activity was observed in all xenografts. Specimens containing hyaluronate showed a highest significant difference (23755 ± 29953, p < .0001). The highest levels of calcium (1.60 ± 0.30) and collagen (1.92 ± 0.09, p < .0001) deposition were also observed with hyaluronate loaded groups. The osteoblasts were well attached and spread on all xenograft groups. However, a higher number of cells were observed with hyaluronate functionalized xenograft (76.27 ± 15.11, (p < .0001) in live cell image analysis and they migrated towards the graft boundaries. The biofunctionalization of xenografts with hyaluronate improves their in vitro performance on human osteoblasts. This suggests that hyaluronate might be able to improve the bone regeneration when using such xenografts.

Evaluation between Biodegradable Magnesium Metal GBR Membrane and Bovine Graft with or without Hyaluronate.

Bone substitutes and barrier membranes are widely used in dental regeneration procedures. New materials are constantly being developed to provide the most optimal surgical outcomes. One of these developments is the addition of hyaluronate (HA) to the bovine bone graft, which has beneficial wound healing and handling properties. However, an acidic environment that is potentially produced by the HA is known to increase the degradation of magnesium metal. The aim of this study was to evaluate the potential risk for the addition of HA to the bovine bone graft on the degradation rate and hence the efficacy of a new biodegradable magnesium metal GBR membrane. pH and conductivity measurements were made in vitro for samples placed in phosphate-buffered solutions. These in vitro tests showed that the combination of the bovine graft with HA resulted in an alkaline environment for the concentrations that were used. The combination was also tested in a clinical setting. The use of the magnesium metal membrane in combination with the tested grafting materials achieved successful treatment in these patients and no adverse effects were observed in vivo for regenerative treatments with or without HA. Magnesium based biodegradable GBR membranes can be safely used in combination with bovine graft with or without hyaluronate.

Differences in Mechanical and Physicochemical Properties of Several PTFE Membranes Used in Guided Bone Regeneration.

Non-resorbable PTFE membranes are frequently used in dental-guided bone regeneration (GBR). However, there is a lack of detailed comparative studies that define variations among commonly used PTFE membranes in daily dental clinical practice. The aim of this study was to examine differences in physicochemical and mechanical properties of several recent commercial PTFE membranes for dental GBR (CytoplastTM TXT-200, permamem®, NeoGen®, Surgitime, OsseoGuard®-TXT, OsseoGuard®-NTXT). Such differences have been rarely recorded so far, which might be a reason for the varied clinical results. For that reason, we analyzed their surface architecture, chemical composition, tensile strength, Young's modulus, wettability, roughness, density, thickness and porosity. SEM revealed different microarchitectures among the non-textured membranes; the textured ones had hexagonal indentations and XPS indicated an identical spectral portfolio in all membranes. NeoGen® was determined to be the strongest and OsseoGuard®-TXT was the most elastic. Wettability and roughness were highest for Surgitime but lowest for OsseoGuard®-NTXT. Furthermore, permamem® was the thinnest and NeoGen® was identified as the thickest investigated GBR membrane. The defect volumes and defect volume ratio (%) varied significantly, indicating that permamem® had the least imperfect structure, followed by NeoGen® and then Cytoplast TM TXT-200. These differences may potentially affect the clinical outcomes of dental GBR procedures.

Peri-Implant Mucosa Augmentation with an Acellular Collagen Matrix.

Peri-implant keratinized mucosa (PI-KM) may support implant survival. Acellular collagen matrices (aCMs) have been widely used to facilitate soft tissue regeneration. The aim of this study was to investigate clinical outcomes obtained with the use of an aCM (mucoderm®) to enhance PI-KM. In this retrospective non-randomized case series, 27 restored implants in 14 patients (eight males and six females, mean age = 56 years) with a PI-KM width ≤ 1 mm were followed for 6 months. It was demonstrated that aCM grafts augmented PI-KM effectively (mean increase of 5.4 mm; >533%) without a significant change in bleeding on probing (BOP) from baseline. The mean aCM shrinkage was 3.9 mm (42%). Gender, area, arch, and BOP did not influence PI-KM augmentation or aCM shrinkage significantly. The present results demonstrated that the examined aCM was effective and predictable for attaining a band of keratinized tissue, while avoiding graft donor site harversting.

Open-Healing Socket Preservation with a Novel Dense Polytetrafluoroethylene (dPTFE) Membrane: A Retrospective Clinical Study.

Background and objectives: Non-resorbable dense polytetrafluoroethylene (dPTFE) membranes are widely used for regeneration procedures, alone or in combination with particulate materials. The aim of this work was to examine the efficacy of a newly developed dPTFE membrane in the management of extraction socket healing. Materials and Methods: The extraction premolar sockets of 44 patients (20 men and 24 women) were preserved. One group received prosthetic rehabilitation with a fixed partial denture (FPD) (PROS group, N = 19) and a second group received immediate implant placement (IMPL group, N = 25). The PROS group sockets were augmented with a bovine derived xenograft and covered with a newly developed dPTFE membrane prior to FPD rehabilitation. Results: In the IMPL group, socket preservation was combined with immediate implant placement. Before (T0) and 6 months after surgery (T1), horizontal and vertical dimensions were measured with customized stents. No significant differences in alveolar bone loss from T0 to T1 were observed between the PROS and IMPL groups in the horizontal dimension for any tooth type. There was a significant difference in alveolar bone loss from T0 to T1 between the two groups for only single-rooted maxillary premolars in the vertical dimension. Conclusions: The use of the examined new dPTFE membrane consistently led to the preservation of hard tissue in the extraction sites.

Periorbital Reconstruction by "Periorbital Patch" Technique Using a Pericardium-Based Collagen Membrane and Titanium Mesh.

OBJECTIVE: Titanium mesh is a commonly used material for the reconstruction of orbital floor fractures. However, in some instances, a subsequent inflammatory reaction can occur that causes the adhesion of orbital tissue to the titanium mesh. The adhesion of the orbital soft tissue to the mesh causes diplopia, lid rigidity and extraocular movements restriction. This study was performed to determine if the placement of a collagen membrane over a titanium mesh can prevent the adhesion of orbital soft tissue for an improved clinical outcome. Clinical considerations: A case study was performed investigating 106 patients undergoing a periorbital restoration. Seventy-two patients received a titanium mesh without a barrier membrane, 12 patients received a barrier membrane composed of autologous auricular cartilage to provide a barrier function and 22 patients received a pericardium collagen membrane and titanium mesh. CONCLUSIONS: Titanium has been shown to generate an intense inflammatory reaction in host tissues, which can cause fibrosis to adjacent structures. Fibrosis is an essential factor in the repair of fracture sites, however this can lead to adverse effects in the orbital socket. Fibrosis can cause cicatrization and lower eyelid retraction when induced along the lower orbital rim. An improved outcome can be achieved by using a barrier between the titanium mesh and the soft tissue, such as autogenous auricular cartilage, however, only patients treated with a resorbable collagen membrane to act as a soft tissue barricade during site regeneration, prevented the fibrosis reaction and related problems from occurring.

Hydrophilicity, Viscoelastic, and Physicochemical Properties Variations in Dental Bone Grafting Substitutes.

The indication-oriented Dental Bone Graft Substitutes (DBGS) selection, the correct bone defects classification, and appropriate treatment planning are very crucial for obtaining successful clinical results. However, hydrophilic, viscoelastic, and physicochemical properties' influence on the DBGS regenerative potential has poorly been studied. For that reason, we investigated the dimensional changes and molecular mobility by Dynamic Mechanical Analysis (DMA) of xenograft (cerabone®), synthetic (maxresorb®), and allograft (maxgraft®, Puros®) blocks in a wet and dry state. While no significant differences could be seen in dry state, cerabone® and maxresorb® blocks showed a slight height decrease in wet state, whereas both maxgraft® and Puros® had an almost identical height increase. In addition, cerabone® and maxresorb® blocks remained highly rigid and their damping behaviour was not influenced by the water. On the other hand, both maxgraft® and Puros® had a strong increase in their molecular mobility with different damping behaviour profiles during the wet state. A high-speed microscopical imaging system was used to analyze the hydrophilicity in several naturally derived (cerabone®, Bio-Oss®, NuOss®, SIC® nature graft) and synthetic DBGS granules (maxresorb®, BoneCeramic®, NanoBone®, Ceros®). The highest level of hydrophilicity was detected in cerabone® and maxresorb®, while Bio-Oss® and BoneCeramic® had the lowest level of hydrophilicity among both naturally derived and synthetic DBGS groups. Deviations among the DBGS were also addressed via physicochemical differences recorded by Micro Computed Tomography, Scanning Electron Microscopy, Fourier Transform Infrared Spectroscopy, X-ray powder Diffractometry, and Thermogravimetric Analysis. Such DBGS variations could influence the volume stability at the grafting site, handling as well as the speed of vascularization and bone regeneration. Therefore, this study initiates a new insight into the DBGS differences and their importance for successful clinical results.

A double-layer patch design for local and controlled drug delivery as an intraoperative custom-made implant-coating technology.

BACKGROUND: The specific biological need of patients frequently becomes obvious just in the intraoperative setting. We hypothesized that a double-layer patch approach that allowed rapid attachment to an implant surface would represent a potential solution for technically challenging intraoperative personalized local drug delivery. METHODS: Dexamethasone-loaded poly[(rac-lactide)-co-glycolide] (PLGA) microparticles were embedded within a polyvinyl alcohol (PVA) patch that was attached to metal implant surfaces by in situ polymerization of alkyl-2-cyanoacrylates (CAs). Hydroxyapatite (HA) nanoparticles were also embedded in the PVA patch. RESULTS: Very rapid dexamethasone-release profiles were observed from the PLGA microparticles / PVA patches. The incorporation of HA nanoparticles into the PVA enabled control of CA penetration within the patch, and improved significantly its attachment, while no interference with the drug release was observed. CONCLUSIONS: Double-layered patches with 1 layer for drug delivery and 1 as gluing interface could represent a solution for safe and controlled local drug delivery from implant surfaces or other, even biological, materials. The technology platform presented here opens the opportunity for personalized medicine by allowing local administration of drugs with customized release based on an intraoperative application.

Intra-operatively customized implant coating strategies for local and controlled drug delivery to bone.

Bone is one of the few tissues in the human body with high endogenous healing capacity. However, failure of the healing process presents a significant clinical challenge; it is a tremendous burden for the individual and has related health and economic consequences. To overcome such healing deficits, various concepts for a local drug delivery to bone have been developed during the last decades. However, in many cases these concepts do not meet the specific requirements of either surgeons who must use these strategies or individual patients who might benefit from them. We describe currently available methods for local drug delivery and their limitations in therapy. Various solutions for drug delivery to bone focusing on clinical applications and intra-operative constraints are discussed and drug delivery by implant coating is highlighted. Finally, a new set of design and performance requirements for intra-operatively customized implant coatings for controlled drug delivery is proposed. In the future, these requirements may improve approaches for local and intra-operative treatment of patients.