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


The effect of altering the lateral occlusion scheme on peri-implant strain: a laboratory study

Jennifer Lo, Jaafar Abduo, and Joseph Palamara

In many instances oral implants provide ideal replacement of missing teeth. However, the literature consistently report occurrence of biological and mechanical complications. One of the factors that are believed to contribute to implant complications is how the implant crown meets the opposing teeth, which is known as occlusion. Therefore, the clinical recommendation is to avoid heavy occlusal loading and uncontrolled occlusal contacts on implant crowns. This study aimed to evaluate the effect of four different occlusions and loading sites on strains around an upper canine implant. A resin maxillary model with a canine implant was fabricated. Four different crowns with different occlusions were manufactured by a commercial dental laboratory. All the crowns were loaded similarly in three different sites: (1) centre of the tooth, (2) 1 mm from the centre and (3) 2 mm from the centre. For each testing cycle, the strain development within the resin surrounding the implant was recorded. The results showed that the strain development was influenced by the occlusion design and the loading sites. However, the loading site had greater influence on strain magnitude than the occlusion design. As the loading site moves away from the centre, the strain magnitude increases significantly. Therefore, it is recommended when restoring a single implant to design the crown in a way that it will reduce the lateral loads during function.

The application of novel nanoengineered implants for craniosynostosis therapy

M. Bariana, S. Ranjitkar, J.A. Kaidonis, D. Losic, G.C. Townsend and P. Anderson

Craniosynostosis is a paediatric condition caused by premature closure of skull sutures. The future of treatment lies in delivery of glypicans proteins to slow down suture fusion, but the lack control over release rate and concentration beyond few days remains a major challenge. Our nanoimplant-based system overcame these problems for 20 days and holds promise for more future developments to come.

The effect of bisphosphonates on osseointegration of implants with different surface topography: An experimental study in rats.

M. Hou, S.B. Lee, Z. Du, S Hamlet, Y. Xiao, S. Ivanovski
The use of bone sparing medications (bisphosphonates such as zoledronate) can affect bone healing, and hence may influence clinical treatment with dental implants. This study showed that zoledronate negatively effects the integration of dental implants into the jaw bone. This negative effect is partially reduced by the use of implants with micro-roughened surfaces. Therefore, the use of dental implants with micro-roughened surfaces is recommended in patients undergoing treatment with bisphosphonates, especially zolendronate.


Fit of CAD/CAM frameworks to conical connection implants as determined by micro-CT

Nicholas D.J. Palfreyman, Roy B.Judge, Joseph E.A. Palamara, BCSc, Dip Ed, PhD Geoffrey G. Adams, Jaafar T.Abduo
"When multiple implants are used in the replacement of missing teeth, a framework is required to connect the implants. How well this framework fits is thought to affect the outcome of treatment. Using Micro Computed Tomography the fit of titanium frameworks connected directly to two implants (11 conical connection) was compared the fit of frameworks connected via intermediate abutments. The study found slightly increased gaps in the latter group, but as these gaps are elevated away from the bone by the abutments, the clinical significance is unclear and needs further investigation."

Novel debridement methods of dental implant surfaces contaminated by a dental biofilm: a proof of concept study

C Tran, C Yip, M Wei, N Meredith, LJ Walsh
Because the surfaces of dental implants are difficult to clean, this study compared the effectiveness of different techniques using laboratory models of dental plaque or an ink applied to the surface which copies the properties of dental plaque. Using hand operated or powered ultrasonic scalers caused surface damage to titanium surfaces, which varied according to the application time and type of tip used. These scalers were not very effective at cleaning the complex surfaces of dental implants. In contrast, particle powder beams (air abrasion) was better at cleaning, and caused less damage to the titanium surfaces. The study showed that once dental plaque has formed on the rough surfaces of dental implants, it is extremely difficult to remove using currently available techniques. Abrasive powders are superior to ultrasonic scalers and hand instruments.


Implant surface debridement using lasers

T Fenelon, C Tran, L Chai, R George, LJ Walsh
Dental implants are widely used to replace missing teeth, but the surfaces of implant threads are difficult to clean if these become exposed. This study examined how different types of pulses delivered from a laser can interact with smooth and rough surfaces of the titanium used in most dental implants. A range of different methods for delivering laser energy onto the surface were examined, and the extent of surface change measured. Laser pulses with low energy could be delivered onto the surface in a way that provides a shockwave to clean the surface but without damaging the metal surface.

Effectiveness of implant surface debridement using particle beams at differing air pressures

Max Chang Ting Wei, Carol Tran, Professor Laurence J Walsh
Dental implants have different chemical and physical properties compared to teeth. Normal teeth cleaning methods may struggle to treat or prevent infections related to implants.
This study looks into air abrasive systems to determine the most effective cleaning settings along with certain powder types at different air pressures. The results indicate that sodium bicarbonate and calcium carbonate powders produce good outcomes in cleaning while not altering surfaces at low air pressures.

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

Yu-Sheng Huang, Cedryck Vaquette, Siamak Saifzadeh, Saso 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

Arash Oveissian, Massimilliano Guazzato, Iven 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.