Reactive Inkjet Printing of Regenerated Silk Fibroin Films for Use as Dental Barrier Membranes.

Current commercially available barrier membranes for oral surgery have yet to achieve a perfect design. Existing materials used are either non-resorbable and require a second surgery for their extraction, or alternatively are resorbable but suffer from poor structural integrity or degrade into acidic by-products. Silk has the potential to overcome these issues and has yet to be made into a commercially available dental barrier membrane.

3D printed tissue engineered model for bone invasion of oral cancer.

Recent advances in three-dimensional printing technology have led to a rapid expansion of its applications in tissue engineering. The present study was designed to develop and characterize an in vitro multi-layered human alveolar bone, based on a 3D printed scaffold, combined with tissue engineered oral mucosal model. The objective was to incorporate oral squamous cell carcinoma (OSCC) cell line spheroids to the 3D model at different anatomical levels to represent different stages of oral cancer.

safety and efficacy testing of a thermally triggered injectable hydrogel scaffold for bone regeneration and augmentation in a rat model.

Bone loss resulting from degenerative diseases and trauma is a significant clinical burden which is likely to grow exponentially with the aging population. In a number of conditions where pre-formed materials are clinically inappropriate an injectable bone forming hydrogel could be beneficial. The development of an injectable hydrogel to stimulate bone repair and regeneration would have broad clinical impact and economic benefit in a variety of orthopedic clinical applications.

Characterization of Multilayered Tissue-Engineered Human Alveolar Bone and Gingival Mucosa.

Advances in tissue engineering have permitted assembly of multilayered composite tissue constructs for potential applications in the treatment of combined hard and soft tissue defects and as an alternative in vitro test model to animal experimental systems. The aim of this study was to develop and characterize a novel three-dimensional combined human alveolar bone and gingival mucosal model based on primary cells isolated from the oral tissues. Bone component of the model was engineered by seeding primary human alveolar osteoblasts into a hydroxyapatite/tricalcium phosphate scaffold and culturing in a spinner bioreactor.

The significance of cell-related challenges in the clinical application of tissue engineering.

Tissue engineering is increasingly being recognized as a new approach that could alleviate the burden of tissue damage currently managed with transplants or synthetic devices. Making this novel approach available in the future for patients who would potentially benefit is largely dependent on understanding and addressing all those factors that impede the translation of this technology to the clinic. Cell-associated factors in particular raise many challenges, including those related to cell sources, up- and downstream techniques, preservation, and the creation of in vitro microenvironments that enable cells to grow and function as far as possible as they would in vivo.

Repair of bone defects in vivo using tissue engineered hypertrophic cartilage grafts produced from nasal chondrocytes.

The regeneration of large bone defects remains clinically challenging. The aim of our study was to use a rat model to use nasal chondrocytes to engineer a hypertrophic cartilage tissue which could be remodelled into bone in vivo by endochondral ossification. Primary adult rat nasal chondrocytes were isolated from the nasal septum, the cell numbers expanded in monolayer culture and the cells cultured in vitro on polyglycolic acid scaffolds in chondrogenic medium for culture periods of 5-10 weeks.

Development of three-dimensional tissue engineered bone-oral mucosal composite models.

Tissue engineering of bone and oral mucosa have been extensively studied independently. The aim of this study was to develop and investigate a novel combination of bone and oral mucosa in a single 3D in vitro composite tissue mimicking the natural structure of alveolar bone with an overlying oral mucosa. Rat osteosarcoma (ROS) cells were seeded into a hydroxyapatite/tri-calcium phosphate scaffold and bone constructs were cultured in a spinner bioreactor for 3 months.

The biological seal of the implant-soft tissue interface evaluated in a tissue-engineered oral mucosal model.

For dental implants, it is vital that an initial soft tissue seal is achieved as this helps to stabilize and preserve the peri-implant tissues during the restorative stages following placement. The study of the implant-soft tissue interface is usually undertaken in animal models. We have developed an in vitro three-dimensional tissue-engineered oral mucosal model (3D OMM), which lends itself to the study of the implant-soft tissue interface as it has been shown that cells from the three-dimensional OMM attach onto titanium (Ti) surfaces forming a biological seal (BS).

Determination of relative in vivo osteoconductivity of modified potassium fluorrichterite glass-ceramics compared with 45S5 bioglass.

Potassium fluorrichterite (KNaCaMg(5)Si(8)O(22)F(2)) glass-ceramics were modified by either increasing the concentration of calcium (GC5) or by the addition of P(2)O(5) (GP2). Rods (2 × 4 mm) of stoichiometric fluorrichterite (GST), modified compositions (GC5 and GP2) and 45S5 bioglass, which was used as the reference material, were prepared using a conventional lost-wax technique. Osteoconductivity was investigated by implantation into healing defects in the midshaft of rabbit femora.

Evaluation of osteoconductive and osteogenic potential of a dentin-based bone substitute using a calvarial defect model.

The aim of this study was to assess the osteoconductive and osteogenic properties of processed bovine dentin using a robust rabbit calvarial defect model. In total, 16 New Zealand White rabbits were operated to create three circular defects in the calvaria. One defect was left unfilled, one filled with collected autogenous bone, and the third defect was filled with the dentin-based bone substitute.

Ultrastructural analysis of implant-soft tissue interface on a three dimensional tissue-engineered oral mucosal model.

A three dimensional tissue-engineered human oral mucosal model (3D OMM) used in the investigation of implant-soft tissue interface was recently reported. The aim of this study was to examine the ultrastructural features of soft tissue attachment to various titanium (Ti) implant surfaces based on the 3D OMM. Two techniques, that is, focus ion beam (FIB) and electropolishing techniques were used to prepare specimens for transmission electron microscopic (TEM) analysis of the interface.

Biological evaluation of nano-hydroxyapatite-zirconia (HA-ZrO2) composites and strontium-hydroxyapatite (Sr-HA) for load-bearing applications.

The biological response of strontium (Sr) doped hydroxyapatite (HA) and hydroxyapatite-zirconia (HA-ZrO₂) composites produced by employing sol-gel technology, minimal ZrO₂ loadings, and novel microwave-sintering regimes thereby retarding decomposition, is reported. In vitro evaluations indicate that all materials induce a favorable response from rat osteosarcoma cells. In vivo evaluations show osteoconductivity and biocompatibility for both the Sr-HA and HA-ZrO₂.

In vitro biocompatibility of modified potassium fluorrichterite and potassium fluorrichterite-fluorapatite glass-ceramics.

Potassium fluorrichterite (KNaCaMg(5)Si(8)O(22)F(2)) glass-ceramics were modified by either increasing the concentration of calcium in the glass (GC5), or by the addition of P(2)O(5) to produce potassium fluorrichterite-fluorapatite (GP2). The solubility of the stoichiometric composition (GST), GC5 and GP2 were measured using the standard test described in ISO 6872:1995 (Dental Ceramics). Ion release profiles were determined for Si, Ca, Mg, Na, K and P using inductively coupled plasma mass spectrometry and fluoride ion (F(-)) concentration was measured using an ion-selective electrode.

Prediction of osteoconductive activity of modified potassium fluorrichterite glass-ceramics by immersion in simulated body fluid.

Potassium fluorrichterite (KNaCaMg(5)Si(8)O(22)F(2)) glass-ceramics were modified by either increasing the concentration of calcium (GC5) or by the addition of P(2)O(5) (GP2). The stoichiometric composition (GST), GC5 and GP2 were soaked in simulated body fluid (SBF) along with 45S5-type bioglass as a control. After immersion, surface analyses were performed using thin-film X-ray diffraction (TF-XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and Fourier-transform infrared (reflection) spectroscopy (FT-IR).

Development of a novel model for the investigation of implant-soft tissue interface.

Background: In dental implant treatment, the long-term prognosis is dependent on the biologic seal formed by the soft tissue around the implant. The in vitro investigation of the implant-soft tissue interface is usually carried out using a monolayer cell-culture model that lacks a polarized-cell phenotype. This study developed a tissue-engineered three-dimensional oral mucosal model (3D OMM) to investigate the implant-soft tissue interface.

Biologic assessment of antiseptic mouthwashes using a three-dimensional human oral mucosal model.

Background: The biologic safety profile of oral health care products is often assumed on the basis of simplistic test models such as monolayer cell culture systems. We developed and characterized a tissue-engineered human oral mucosal model, which was proven to represent a potentially more informative and more clinically relevant alternative for the biologic assessment of mouthwashes. The aim of this study was to evaluate the biologic effects of alcohol-containing mouthwashes on an engineered human oral mucosal model.

Development of biodegradable electrospun scaffolds for dermal replacement.

Our objective is to develop a synthetic biodegradable replacement dermal substitute for tissue engineering of skin and oral mucosa. Our in vivo criteria were that candidate scaffolds should allow surrounding cells to migrate fully into the scaffolds, enabling vasculogenesis and remodelling without invoking a chronic inflammatory response. We examined a total of six experimental electrospun polymer scaffolds: (1) poly-l-lactide (PLLA); (2) PLLA+10% oligolactide; (3) PLLA+rhodamine and (4-6) three poly(d,l)-lactide-co-glycolide (PLGA) random multiblock copolymers, with decreasing lactide/glycolide mole fractions (85:15, 75:25 and 50:50).

Mucotoxicity of dental composite resins on a tissue-engineered human oral mucosal model.

Objective: Tissue-engineered human oral mucosal models have been developed for biocompatibility assessment of biomaterials. The aim of this study was to evaluate the biological effects of three different composite resin systems on a three-dimensional human oral mucosal model.

Methods: Full-thickness oral mucosal models were engineered by air/liquid interface culture of a human oral keratinocyte cell line on a lamina propria composed of oral fibroblasts seeded into a porous scaffold.

The effect of investment materials on the surface of cast fluorcanasite glasses and glass-ceramics.

Modified fluorcanasite glass-ceramics were produced by controlled two stage heat-treatment of as-cast glasses. Castability was determined using a spiral castability test and the lost-wax method. Specimens were cast into moulds formed from gypsum and phosphate bonded investments to observe their effect on the casting process, surface roughness, surface composition and biocompatibility.

Bespoke human hypertrophic chondrocytic cell lines provide the osteoinductive signals required for vascularized bone formation.

Hypertrophic cartilage provides the morphological and biochemical template for orchestrating bone growth. To produce a bone-inductive material such as hypertrophic cartilage for clinical use, we have conditionally immortalized hypertrophic chondrocytic cells from human femur and expanded them in vitro through more than 145 divisions. The clonal cell lines generated by this process consistently express signals that induce both rat and human marrow cells to differentiate in vitro into osteoblastic cells.

Localization of type VI collagen in tissue-engineered cartilage on polymer scaffolds.

Together, the chondrocyte and its pericellular matrix have been collectively termed the chondron. Current opinion is that the pericellular matrix has both protective and signalling functions between chondrocyte and extracellular matrix. Formation of a native chondrocyte pericellular matrix or chondron structure might therefore be advantageous when tissue engineering a functional hyaline cartilage construct.

Cytotoxicity of resin monomers on human gingival fibroblasts and HaCaT keratinocytes.

Objectives: The aim of this study was to evaluate and compare the biological effects of three resin monomers on three human gingival fibroblast (HGF) cell lines and immortalised human keratinocytes.

Methods: Primary HGFs and HaCaT keratinocytes were cultured for 24h and grown to sub-confluent monolayers. Resin monomers were dissolved in dimethyl sulphoxide (DMSO) and diluted with culture medium.

The effect of calcium fluoride (CaF(2)) on the chemical solubility of an apatite-mullite glass-ceramic material.

Objective: To assess the effect of varying CaF(2) on the chemical solubility of apatite-mullite glass-ceramic (G-C) materials in both the glassy and crystallized states.

Methods: Apatite-mullite forming glasses used in this study are ionomer cement derivatives based on the general formula (4.5SiO(2)-3Al(2)O(3)-1.

Sinus augmentation bone grafts for the provision of dental implants: report of clinical outcome.

Purpose: The aim of this study was to report the outcome of sinus augmentation surgery with autogenous bone grafting in routine dental implant practice.

Materials And Methods: Twenty-seven sinus augmentation procedures were undertaken on 18 consecutive patients (mean age 43.7 years).