Tien-Min Gabriel Chu

Indiana University-Purdue University Indianapolis | IUPUI · Biomedical and Applied Sciences, School of Dentistry

Dicalcium phosphate dihydrate (DCPD) cements are typically prepared using beta-tricalcium phosphate (beta-TCP) as the base component. However, hydroxyapatite (HA) is an interesting alternative because of its potential for reducing cement acidity, as well as modulating cement properties via ionic substitutions. In the present study, we have characte...

Objective: Varying the concentrations of inhibitor such as butyl hydroxytoluene (BHT) has been shown to be effective in reducing the polymerization shrinkage of composite. However, how BHT will affect the water sorption and mechanical property after the composite is service for extended amount of time is still unknown. For this reason, this project...

Dental pulp stem cells (DPSCs) have drawn much interest for the regeneration of mineralized tissues, and several studies have compared DPSCs to bone marrow-derived mesenchymal stem cells (BMMSCs). However, conflicting results, possibly due to donor-associated variability, have been published and the regenerative potential of DPSCs is currently uncl...

The optimal degree of curing throughout the bulk of a visible light-activated dental resin composite is acknowledged to be important to the clinical success of a resin composite restoration. Unfortunately, the dentist has no means of monitoring the cure of the resin surfaces not directly exposed to the curing light. Techniques, such as the layered...

Recent studies have shown that mesenchymal stem cells (MSC) with the potential for cell-mediated therapies and tissue engineering applications can be isolated from extracted dental tissues. Here, we investigated the collection, processing, and cryobiological characteristics of MSC from human teeth processed under current good tissue practices (cGTP...

We have developed a high-strength light-cured glass-ionomer cement (LCGIC). The polymer in the cement was composed of the 6-arm star-shape poly(acrylic acid) (PAA), which was synthesized using atom-transfer radical polymerization. The polymer was used to formulate with water and Fuji II LC filler to form LCGIC. Compressive strength (CS) was used as...

Conventional histologic or histomorphometric evaluation provides clear evidence of the bone healing process. However, the sample preparation process is tedious and destructive, and the three-dimensional (3D) anisotropic information of the bone trabeculae is compromised. Micro-computed tomography (microCT) has been introduced as an alternative to th...

Segmental defect regeneration has been a clinical challenge. Current tissue-engineering approach using porous biodegradable scaffolds to delivery osteogenic cells and growth factors demonstrated success in facilitating bone regeneration in these cases. However, due to the lack of mechanical property, the porous scaffolds were evaluated in non-load...

Large segmental defects in bones can result from tumor removal, massive trauma, congenital malformation, or non-union fractures. Such defects often are difficult to manage and require multiple-phase surgery to achieve adequate union and function. In this study, we propose a novel design of bone morphogenetic protein 2 (BMP-2) carrier for tissue eng...

Segmental defects in long bones pose a clinical challenge in orthopaedic surgery. These defects often require multiple surgeries to achieve the desired bridging and union. Bone morphogenetic protein 2 (BMP-2) has been used extensively to facilitate regeneration in these large defects. The two important roles that BMP-2 has to play in large defect r...

The reconstruction of segmental defect in long bone is a clinical challenge. Multiple surgeries are typically required to restore the structure and function of the affected defect site. In order to overcome this defect a biodegradable bone tissue engineering scaffold is used. This scaffold acts as a carrier of proteins and growth factors, while als...

Dicalcium phosphate dihydrate (DCPD) cement was effective in our prior study as a bone morphogenetic protein-2 (BMP-2) delivery vehicle in a rat segmental defect regeneration study. In this study, we investigated the effects of liquid-to-powder (L/P) ratio on the in vitro degradation and protein release behavior of this material. The L/P ratios use...

A biodegradable polymer network hydrogel was fabricated and characterized for neural tissue engineering purposes. The proposed hydrogel contains both hydrophobic and hydrophilic components. The hydrophobic component is a three-arm poly(e-caprolactone) maleic acid with molecular weight of 900 (PCLTMA), and the hydrophilic component is poly(ethylene...

The objective of this study was to investigate the effects of temperature and solids loading on the viscosity of two nonaqueous ceramic suspensions. In this article, the viscosity of Al2O3 suspensions with 5%–50% solids loading and hydroxyapatite suspensions with a solids loading of 5%–40% were measured at temperatures of 25°, 45°, 65°, and 75°C. T...

Bone tissue engineering utilizes scaffolds to deliver biofactors including cells, genes, and proteins to regenerate bone. The scaffold itself must fulfill three primary functions to ensure successful treatment of bone defects. First, the scaffold must provide the correct anatomic geometry to define and maintain the space for tissue regeneration. Se...

Bone tissue engineering utilizes biomaterial scaffolds seeded with biofactors (cells, genes, and/or proteins) to reconstruct bone defects. The scaffolds must be able to temporarily bear load, shape regenerate tissue, and enhance tissue regeneration through biofactor delivery. Thus, scaffold evaluation requires traditional engineering experiments li...

Internal architecture has a direct impact on the mechanical and biological behaviors of porous hydroxyapatite (HA) implants. However, traditional processing methods provide very minimal control in this regard. This paper reviews a novel processing technique developed in our laboratory for fabricating scaffolds with controlled internal architectures...

Internal architecture has a direct impact on the mechanical and biological behaviors of porous hydroxyapatite (HA) implant. However, traditional processing methods provide minimal control in this regard. To address the issue, we developed a new processing method combining image-based design and solid free-form fabrication. We have previously publis...

Porous hydroxyapatite (HA) has been used as a bone graft material in the clinics for decades. Traditionally, the pores in these HAs are either obtained from the coralline exoskeletal patterns or from the embedded organic particles in the starting HA powder. Both processes offer very limited control on the pore structure. A new method for manufactur...

Internal architecture has a direct impact on the mechanical and biological behaviors of porous hydroxyapatite (HA) implants. However, traditional processing methods provide very minimal control in this regard. This paper reviews a novel processing technique developed in our laboratory for fabricating scaffolds with controlled internal architectures...

Trabecular bone architecture is a significant determinant of both its effective stiffness and strength. Developing a mathematical equation to characterize stiffness and strength dependence on architecture, known as astructure function relationshiphas two important applications: 1)predicting bone fragilityand 2)designing scaffolds to regenerate bone...

This article will present an image-based approach to the designing and manufacturing of biomimetic tissue engineered temporomandibular (TMJ) condylar prosthesis. Our vision of a tissue-engineered TMJ prosthesis utilizes a 3-D designed and manufactured biodegradable scaffold shaped similar to a condylar head and neck, i.e. a condylar-ramus unit (CRU...

Although both bone grafting and synthetic material reconstruction have been successful in many applications, their shortcomings have motivated a third approach to bone reconstruction, tissue engineering. Tissue engineering combines biologic regenerative factors, like stromal cells or growth factors, with biodegradable material scaffolds, like calci...

The objective of this study is to use differential scanning calorimetry (DSC) to characterize the curing kinetics of Al2O3 and hydroxyapatite suspensions in acrylates. The heat evolution of the acrylate premix and ceramic suspensions in dynamic and isothermal curing was measured. The calculated activation energies for the acrylate premix and the tw...

This article will present an image-based approach to design and manufacture of scaffolds for the tissue engineering of bone and cartilage constructs. Our vision of tissue-engineered bone and/or cartilage constructs utilizes 3-D designed and manufactured biodegradable scaffolds that are site specific for the area of maxillofacial reconstruction. The...

Bone tissue engineering (BTE), which combines biomaterial scaffolds with biologically active factors, holds tremendous promise for reconstructing craniofacial defects. A significant challenge in craniofacial reconstructive BTE applications is the complex patient-specific geometry that must be reconstructed. In this paper, we present an image-based...

Bone tissue engineering (BTE), which combines biomaterial scaffolds with biologically active factors, holds tremendous promise for reconstructing craniofacial defects. A significant challenge in craniofacial reconstructive BTE applications is the complex patient-specific geometry that must be reconstructed. In this paper, we present an image-based...

Thesis (Ph. D.)--University of Michigan. Includes bibliographical references. Photocopy.

Direct ceramic stereolithography (SLA) is done using UV-curable suspensions of powders in acrylates in a conventional SLA machine. Hydroxyapatite prototypes for bone tissue scaffolds are built from Image-Based Design files, featuring an interior architecture of void passages. Complex alumina objects are built as digital sculptures. Piezoelectric ce...

Hydroxyapatite bioceramic was used for the manufacture of an orbital floor prosthesis from spiral CT data acquired transaxially at 1-mm beam collimation, pitch of 1, and 0.2-mm reconstruction intervals. CT data were converted to vector file format for subsequent prosthesis manufacture on a stereo-lithography machine. The orbital floor prosthesis wa...

Internal architecture has a direct impact on the mechanical and biological behaviors of porous hydroxyapatite (HA) implants. However, traditional processing methods provide very minimal control in this regard. This paper reviews a novel processing technique developed in our laboratory for fabricating scaffolds with controlled internal architectures...

The traditional gold and porcelain fused to metal crowns have been challenged by the esthetic all-ceramic crown materials. Only previous experience with poor mechanical properties, lack of standardized tooth preparation, and processing challenges have prevented universal acceptance of all-ceramic crowns. However, stronger and tougher ceramics and u...