The following research articles have been fully or partially funded by the ADRF.

In vitro fracture strength and patterns in root filled teeth restored with different base materials

TCL Chan, S Küçükkaya, R Wong, P Parashos

The choice of base material beneath fillings in teeth can influence the failure mode, which may have implications for the clinical presentation of structural failures of root filled teeth. Four restorative materials (glass ionomer cement, zinc phosphate cement, composite resin and Biodentine®) were tested as intermediate bases under direct resin fillings for root filled premolar teeth. The restorative technique promoted strengths that can withstand normal and maximum masticatory function. The four materials performed equally well.


Rapid prototyped bilayered porous scaffold combined with osteogenic growth factor for vertical bone augmentation

P T Sudheesh Kumar, C Vaquette, S Ivanovski

Following tooth loss, the resorption of jaw bone is a physiological process, and it results the formation of jaw bone defect. This can create major problems for subsequent placement of dental implants. This study demonstrated the use of a 3D printed bilayered scaffold made of biocompatible polymers loaded with bone growth factor can regenerate bone tissue on the existing bone. This scaffold could be used to regenerate jaw bone tissue where adequate bone is required to place dental implants. 


The effect of diabetes on osseointegration of different implant surfaces in rats

R S Lee, S Hamlet, S Ivanovski

Diabetic condition can negatively influence bone healing, compromising clinical outcomes of dental implant treatment. The current study demonstrated that diabetic condition decreased bone formation rate along the implant surface in the intramembranous bone.  However, the negative effect of diabetes in the bone healing following a dental implant treatment could be partially compensated by the use of implants with hydrophilic moderately rough surfaces.

Functional characterisation of genes specific for dental mesenchymal stem cells with high proliferation and differentiation capacity

D Menicanin, S Gronthosm, P M Bartold
Significant emphasis in the field of regenerative medicine has been placed on investigation of mesenchymal stem cells (MSC). These cells have demonstrated vast capacity to repair and regenerate multiple adult tissue types lost or damaged due to injury and/or disease. In this study we examined genes that control the ability for MSC cells to grow and develop into specific tissues. Understanding of these important processes will contribute to predictable and effective therapeutic application of MSC.

The effect of incident beam angle and horizontal distance of the light curing unit on the degree of polymerisation in photo-initiated composite resin dental restorative materials

Dr C Yang, A/Prof M Liddell, Dr E Jennings, Prof P Buttner, Prof N Meredith
The aim of the study is to evaluate the effect of the angle and distance of a curing light (device used to set a dental filling) on the filling material. 3 types of fillings were used (nanohybrid, bulk-fill, flowable) and they were tested at 7 angles, and 5 distances. The fillings were then analysed to find out how much they have “set”. It was found that as the angle between the curing light and the filling increased, the setting of the filling material decreased. As the distance of the curing light from the filling increased, the setting of the filling decreased as well.

The effect of two sodium hypochlorite gels on the structural and chemical properties of dentine, tissue dissolution, and their antimicrobial efficacy in vitro

S Cochrane, M Burrow, P Parashos
In root canal treatment, root canal systems are generally disinfected with sodium (NaOCl) solutions. Recently, research has turned towards the use of NaOCl gels as antibacterial agents between appointments. This research investigated the effects of this gel on tooth tissue (dentine). The results showed that the gels were detrimental to the mechanical properties of dentine. Such gels should be used with caution until further laboratory-based studies are undertaken.

Effect of Local Delivery of VEGF-Hydrogel on BRONJ lesion and local gene expression in Rat Model – An in vivo and in vitro study

D Sharma, S Hamlet, E B Petcu, S Ivanovski
 Dental treatments involving jaw bone, in patients on anti-resorptives such as bisphosphonates (BP), carries a high risk of oral lesions that consists of painful exposure of bone due to the direct effect of BPs on the jaw bone vasculature, termed Bisphosphonate- induced osteonecrosis of jaw. This project aimed to evaluate the potential use of locally delivered gel containing a vascular stimulant (Vascular endothelial growth factor) immediately after surgical dental treatment to significantly reduce the chance of developing this painful condition subsequent to dental treatments.

Investigation of osteoinductive and osteoconductive potential of modified titanium using a novel osteogenesis and regeneration model

YS Huang, C Vaquette, S Saifzadeh, S Ivanovski
 Titanium is a commonly used biomaterial in dental implantology. Previous studies have shown that titanium surfaces that has been specifically modified are able to accelerate bone formation and implant integration. In this study, it was shown that a titanium surface that was blasted with titanium oxide particle and etched with hydrofluoric acid produced a surface that was more favourable for bone formation, which could be observed as early as 2 weeks after implant placement. In summary, the modified surface demonstrated superior capacity for bone formation.


Flexural Strength and sensitivity to low temperature degradation of high translucency zirconia

A Oveissian, M Guazzato, I Klineberg
 Zirconia dental restorations have gained popularity because of its strength. However, the strength of new high translucent zirconia has not been investigated. The results of this study showed that translucent zirconia is significantly weaker and more prone to strength degradation than traditional zirconia. The use of newly introduced high translucent zirconia should be limited to anterior single unit restorations. More studies are required to have a better understanding of the properties and clinical indications of high translucent zirconia.


Macrophage Integrin Gene Expression in Response to Titanium Surface Modification

S Hamlet, S Ivanovski
Attachment to the surface of a biomaterial by macrophages, is a critical first step influencing the resultant immune response. This attachment is mediated by a cell surface proteins i.e. ‘integrins’ whose expression differs depending upon the surface topography of the biomaterial encountered. As the role of titanium surface properties on integrin expression by macrophages has not been described, we used rat bone marrow-derived macrophages to shown that the expression of ‘α-integrins’ were significantly upregulated by a nanoscale modified titanium surface.

Novel polymer/mesoporous ceramic composite scaffold: Fabrication and evaluation of bone regeneration potential

P T S Kumar, C Vaquette, S Ivanovski
This study demonstrated the use of a 3D printed scaffold using a biocompatible polymer and ceramic composite. The presence of polymer imparts strength and space to the scaffold whereas the bioceramics provides the bioactivity like enhanced bone growth. This scaffold could be used as a potential biomaterial for dental bone regeneration where adequate bone is required to place dental implants.

Growing Small Particles to Grow Bone

P A Tran, A Matthew, C Vaquette, S Ivanoski, D W Hutmacher
This project focused on decorating barrier membranes and scaffolds used to restore dental bone loss with antimicrobial particles. We have developed a method to grow the selenium particles of “nano” size on to the scaffolds and membrane. The selenium “nanoparticles” demonstrated strong antimicrobial activities and normal bone growth in pre-clinical testing. This promising result has established a strong foundation for translational research of the selenium coating which has the regulatory advantage of being a non-drug surface modification method.

Fibre guiding melt electrospun scaffold and cell sheet technology for the hierarchical regeneration of the periodontium complex

C Vaquette, D W Hutmacher, S Ivanovski
 Melt electrospinning wiring technology enables the depostion of small polymeric fibres in a highly controlled manner. This technique was utilised for the fabrication of fibre guiding scaffold in order to enhance the regenerative outcomes of periodontal treatment. This was achieved by creating channels with guide the orientation of cell and collagen matrix for potentially promoting functional attachment onto the root surface.

Bioactive tissue-engineered constructs for periodontal regeneration

Y. Zhou, L. Chen, C. Vaquette, S. Ivanovski
Periodontitis is an inflammatory disease that can ultimately lead to tooth loss. Present treatments cannot fully restore the complex periodontal structure consisting of soft tissue (gum) and hard tissue (bone). We have developed a tissue-engineered construct, which combines dental stem cells and a supporting scaffold. The cell-scaffold constructs have shown superior performance and achieved predictable regeneration of damaged periodontal tissues. Further study on the application of the tissue-engineered constructs in an inflammatory microenvironment is required.

Preclinical development of a novel porosity indicator for early detection of caries


J E Mangum
Tooth decay is reversible if it is detected early and preventive measures are implemented by dentists. However, those early stages of decay can be difficult to detect and diagnose. This project developed a new diagnostic tool (dental paint) to help dentists diagnose decay earlier and inform preventive treatment decision-making. This new technology shows promise for improving the prevention of tooth decay.

Locally-delivered bioactive agents as treatment modalities in the management of Medication-induced osteonecrosis of the jaws.

D Sharma, S Hamlet, E B Petcu, S Ivanovski
Medication-induced osteonecrosis of jaw is a condition that involves painful exposure of bone, often after dental treatments involving jaw bone due to the direct effect of commonly used prescription anti-resorptive and anti-angiogenic medications on the bone vasculature. This preliminary study evaluated the potential application of hydrogel containing a vascular stimulant (Vascular endothelial growth factor) or bone growth factor (BMP-7) immediately after surgical dental treatment to significantly reduce the chance of developing this painful condition.

New methacrylated bone-derived extracellular matrix hydrogel for craniofacial tissue engineering

F Obregon, A Spahr, MD Habil

Bone defects represent a challenge in the restorative treatment of patients. In this context, different bone grafts are utilised, however, the outcomes achieved are limited.
Using simple biochemistry, our group developed an injectable hydrogel combining bone extracellular matrix proteins with polyethylene glycol diacrylate, which was further optimised and characterised. The hydrogel offered superior biological and physicochemical features as a scaffold for bone regeneration procedures. 

Comparing the Efficacy of Dentine Desensitizing Agents

AL Wee, S Shetty
This lab-based study investigated the effectiveness of 4 different toothpastes and a mouthwash in relieving dentine sensitivity following simulated challenges in the mouth with acid and saliva. The study concluded that Colgate Sensitive Pro-Relief Extra Protect toothpaste (arginine with CalSealTM technology) and Listerine Advanced Defence Sensitive mouthwash (potassium oxalate) performed best among the treatments available, including in an acidic environment. The effectiveness of Colgate Sensitive Pro-Relief toothpaste (arginine) increased in a simulated saliva environment.