Two dimensional alveolar ridge augmentation using particulate hydroxyapatite and collagen membrane: A case report

3D-printed bioactive ceramic scaffolds with biomimetic micro/nano-HAp surfaces mediated cell fate and promoted bone augmentation of the bone–implant interface in vivo

Calcium phosphate bio-ceramics are osteo-conductive, but it remains a challenge to promote the induction of bone augmentation and capillary formation. The surface micro/nano-topography of materials can be recognized by cells and then the cell fate are mediated. Traditional regulation methods of carving surface structures on bio-ceramics employ mineral reagents and organic additives, which might introduce impurity phases and affect the biological results. In a previous study, a facile and novel method was utilized with ultrapure water as the unique reagent for hydrothermal treatment, and a uniform hydroxyapatite (HAp) surface layer was constructed on composite ceramics (β-TCP/CaSiO₃) in situ. Further combined with 3D printing technology, biomimetic hierarchical structure scaffolds were fabricated with interconnected porous composite ceramic scaffolds as the architecture and micro/nano-rod hybrid HAp as the surface layer. The obtained HAp surface layer favoured cell adhesion, alleviated the cytotoxicity of precursor scaffolds, and upregulated the cellular differentiation of mBMSCs and gene expression of HUVECs in vitro. In vivo studies showed that capillary formation, bone augmentation and new bone matrix formation were upregulated after the HAp surface layer was obtained, and the results confirmed that the fabricated biomimetic hierarchical structure scaffold could be an effective candidate for bone regeneration.

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Simple and practical process to construct surface structure layer in situ with little impurities.

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Combined with the 3D printing technology to fabricate architecture of the pre-treated matrix.

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Study the angiogenesis and osteogenesis (for mesenchymal stem cells) separately.

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Improving tissue growth in vivo: capillary formation, bone-augmentation and new bone matrix formation.

Design and evaluation of a novel sub-scaffold dental implant system based on the osteoinduction of micro-nano bioactive glass

Alveolar ridge atrophy brings great challenges for endosteal implantation due to the lack of adequate vertical bone mass to hold the implants. To overcome this limitation, we developed a novel dental implant design: sub-scaffold dental implant system (SDIS), which is composed of a metal implant and a micro-nano bioactive glass scaffold. This implant system can be directly implanted under mucous membranes without adding any biomolecules or destroying the alveolar ridge. To evaluate the performance of the novel implant system in vivo, SDISs were implanted into the sub-epicranial aponeurosis space of Sprague-Dawley rats. After 6 weeks, the SDIS and surrounding tissues were collected and analysed by micro-CT, scanning electron microscopy and histology. Our results showed that SDISs implanted into the sub-epicranial aponeurosis had integrated with the skull without any mobility and could stably support a denture. Moreover, this design achieved alveolar ridge augmentation, as active osteogenesis could be observed outside the cortical bone. Considering that the microenvironment of the sub-epicranial aponeurosis space is similar to that of the alveolar ridge, SDISs have great potential for clinical applications in the treatment of atrophic alveolar ridges. The study was approved by the Animal Care Committee of Guangdong Pharmaceutical University (approval No. 2017370).

Andrew's bridge system: A boon for huge ridge defect in aesthetic zone

Tooth loss may pose a challenge for prosthetics when several missing teeth are associated with huge vertical and horizontal bone defects due to cleft palate, road traffic accidents, congenital defects etc. This case report presents prosthetic rehabilitation of a 22 year old male patient of cleft lip and palate with missing upper front teeth along with severe ridge defect since 1 year due to surgical intervention in premaxillary region. The extensive soft and hard tissue defect in aesthetic region was evident and it made the prosthetic rehabilitation more challenging. Among treatment options, fixed partial denture (FPD) was not feasible due to long edentulous span and extensive soft and hard tissue loss. Psychologically, patient was not ready for removable prosthesis. Patient was also not ready for next implant or bone augmentation surgery procedure. The patient presented with Kennedy class IV edentulous area with Seibert's class III ridge defect, so fixed-removable prosthesis was planned to compensate soft and hard tissue defect. The patient with several missing teeth and extensive visible bony defect in the anterior region was successfully rehabilitated using fixed-removable Andrew's bridge system. Although it is not commonly used by dentist so this present case report shows effective management of huge defect case by very simple and conservative technique.

The Biological Evaluation of Conventional and Nano-Hydroxyapatite-Silica Glass Ionomer Cement on Dental Pulp Stem Cells: A Comparative Study

BACKGROUND

Despite their lower strength, glass ionomer cements (GICs) are widely used as restorative materials because of their anti-cariogenic properties, direct adhesion to tooth structure and good biocompatibility. Recently, the addition of nano-hydroxyapatite (nano-HA)-silica to conventional GIC (cGIC) has been shown to improve the strength of cGIC. However, the biocompatibility and cell attachment properties of this material are unknown.

AIMS

This study aims to evaluate and compare the cytotoxicity and cell attachment properties of cGIC and nano-HA-silica-GIC on dental pulp stem cells (DPSCs).

METHODS AND MATERIALS

Material extracts of nano-HA-silica-GIC and cGIC were prepared into seven serial dilutions and applied to 96 well plates seeded with DPSCs. After 72 h, the cell viability was determined using MTT assay. The DPSCs cell attachment properties were examined under scanning electron microscope (SEM) after 24 and 72 h. Kruskal-Wallis test was used to analyse the data for MTT assay (P < 0.05). SEM images of cell attachment properties were also described.

RESULTS

Nano-HA-silica-GIC and cGIC was shown to be slight to non-cytotoxic at all concentrations, except 200 mg/ml. Moderate cytotoxicity has been observed at 200 mg/ml concentration where nano-HA-silica-GIC and cGIC revealed cell viability values of 44.38 and 42.15%, respectively. Nano-HA-silica-GIC demonstrated better cell viability values than cGIC at all concentrations except for 6.25 and 12.5 mg/ml. Nevertheless, the results were not statistically significant (P > 0.05). SEM examination revealed the increasing numbers of DPSCs attached to both groups with prominent filopodia, especially after 72 h.

CONCLUSIONS

Nano-HA-silica-GIC exhibited good biocompatibility which is comparable to cGIC and favoured the attachment of DPSCs.

The use of hydroxyapatite bone substitute grafting for alveolar ridge preservation, sinus augmentation, and periodontal bone defect: A systematic review

OBJECTIVES

We determined and structurally analyzed the reported effect of hydroxyapatite (HA) bone substitute on alveolar bone regeneration. To the best of our knowledge, no systematic reviews have previously reported the bone regenerative effect of the HA bone substitute.

MATERIALS AND METHODS

A literature search was performed for articles published up to August 2015 using MEDLINE with the search terms "hydroxyapatite," "bone regeneration," and "alveolar bone" as well as their known synonyms. The inclusion criteria were set up for human trials with at least five patients. The literature search, eligible article selection, and data extraction were independently performed by two readers, and their agreement was reported by κ value.

RESULTS

Of the 504 studies found using the MEDLINE literature search, 241 were included for further steps (inter-reader agreement, κ = 0.968). Abstract screening yielded 74 studies (κ = 0.910), with 42 completely fulfilling the inclusion criteria (κ = 0.864). In a final step, 42 studies were further analyzed, with 17 and 25 studies with and without statistical analysis, respectively. The 17 studies reporting similar outcome measures were compared using the calculated 95% confidence intervals. The effect of HA on ridge preservation could not be evaluated.

CONCLUSIONS

The use of the HA bone substitute interfered with the normal healing process, with significant differences found for sinus augmentation but not for periodontal bone defects. Thus, a bone substitute with optimal bone regenerative properties for alveolar ridge or socket preservation, sinus augmentation, and periodontal bony defect should be developed.

3D Printing Nanoscale Bioactive Glass Scaffolds Enhance Osteoblast Migration and Extramembranous Osteogenesis through Stimulating Immunomodulation

Bioactive glass (BG) can repair bone defects, however, it is not clear whether BG has the ability for bone augmentation without making any bone defect. Unlike the intramembranous osteogenesis in bone defect repair, the extramembranous osteogenesis occurs outside the cortical bone and the osteoprogenitor cells show the reversed migration. Herein, nanoscale bioactive glass scaffolds (BGSs) are fabricated, and their role and immunomodulation-related mechanism in the extramembranous osteogenesis are investigated. The in vitro migration and differentiation of calvaria preosteoblasts are studied by culturing with peripheral macrophage-conditioned medium after stimulating with BGSs. The results indicate that the proinflammatory environment significantly promotes preosteoblast migration, but has limited effect on osteogenic differentiation. However, the anti-inflammatory environment and BGSs significantly increase the osteogenic differentiation of preosteoblasts. The in vivo extramembranous osteogenesis evaluation shows that the active osteogenesis is observed near the skull. The osteoblasts derived from the reverse migration of cranial cells can be confirmed by comparing with the scaffolds implanted in back subcutaneous which is just colonized by fibrous tissue. This study may bring a fresh perspective for BG in bone regeneration and explore the osteogenic immunomodulation of peripheral macrophages in a nonosteogenic environment.

Advances in collagen, chitosan and silica biomaterials for oral tissue regeneration: from basics to clinical trials

Different materials have distinct surface and bulk characteristics; each of them potentially useful for the treatment of a particular wound or disease.