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Journal of Oral Science & Rehabilitation No. 1, 2017

B o n e a u g m e n t a t i o n u s i n g p o r o u s (cid:696)-TC PB o n e a u g m e n t a t i o n o f c a n i n e f r o n t a l s i n u s e s u s i n g a p o r o u s (cid:696)-t r i c a l c i u m p h o s p h a te Introduction Materials and methods Implant placement in highly atrophic maxillae has been a major challenge in implant dentistry. Sinus floor elevation is a preferred option in such situ- ations. Various maxillary sinus floor augmenta- tion techniques have been developed for manag- ing severe bone loss in the maxilla.1–4 However, it is important to define the best bone substitute for the subsinus cavity after sinus membrane lift procedures. Although autogenous bone grafting is still considered the gold standard for treatment, it has several disadvantages, including the re- quirement of a second surgery at the donor site and limited bone supply.5, 6 Artificial bone grafts are promising alternatives to autogenous bone grafts. Synthetic hydroxyapatite (HA) has been widely applied in the medical and dental fields because of its high biocompatibility and osteo- conductive properties.7, 8 However, the application of HA has to be carefully considered because it is poorly displaced by new bone tissue9 and is easily adsorbed by bacteria and epithelial cells because of its high surface energy.10, 11 Bovine HA is fre- quently used as a grafting material in sinus lift procedures because of its features that resemble cancellous bone, complete deproteinization of the inorganic component and thus the absence of antigenicity.12 Beta-tricalcium phosphate ((cid:697)-TCP) was one of the earliest calcium phosphate com- pounds used as a bone graft substitute because of its high osteoconductivity, tissue compati bility and ability to withstand suficient mechanical stress.13 High-temperature TCP, known as (cid:696)-TCP, is often prepared by sintering amorphous precur- sors with the proper composition.14 Marukawa et al. demonstrated the usefulness of self-setting (cid:696)-TCP (BIOPEX-R) in maintaining the rigidity of implanted bone screws using maxil- lary sinus augmentation in rabbits.15 However, a drawback of self-setting bone cement is its weak mechanical property. In a previous study, we fab- ricated porous (cid:696)-TCP composites with a contin- uous small-and-large-pore structure and demon- strated that the composite created using porous (cid:696)-TCP particles and collagen or collagen model peptide had enough adaptability for treating skull bone defects in miniature pigs.5 However, the efectiveness of porous (cid:696)-TCP particles as a graft- ing material in sinus lift procedures has not yet been investigated. The objective of this study was to evaluate the effects of porous (cid:696)-TCP as a tissue- engineered scafold using a canine frontal sinus model. M a t e r i a l a n a l y s i s Preparation and characterization of porous (cid:696)-TCP particles Porous (cid:696)-TCP particles with an average diame- ter of 580.8 μm and porosity of about 80% were obtained from Taihei Chemical Industrial (Osaka, Japan) and sterilized by dry heating before the experiment. A field-emission scanning electron microscope (S-4100, Hitachi High-Technologies Corporation, Tokyo, Japan) was used to analyze particle size, pore distribution and outer surface conditions. Before observation, samples were coated with platinum–palladium using the E-1030 (Hitachi High-Technologies Corporation). (cid:696)-TCP particles were characterized using a powder X-ray difraction system (XRD; XRD- 6100, Shimadzu, Kyoto, Japan). XRD patterns were obtained with the following parameters: 40 kV, 30 mA, scan rate of 2°/min and step size of 0.05° within a range of 10–60°. Crystal phase was characterized using data from the Interna- tional Centre for Difraction Data (HA: 9-0432; (cid:696)-TCP: 9-0348). X-ray photoelectron spectros- copy (XPS) measurements were performed to determine the surface Ca/P atomic ratios with a PHI X-tool (Ulvac-Phi, Chigasaki, Japan) equipped with an Al–K(cid:696) radiation source (15 kV; 53 W; spot size of 205 μm) at a pass energy of 280.0 eV, a step size of 0.1 eV and a takeof angle of 45° with 20 scans. A n i m a l m o d e l s The mandibular defect model was established using six healthy beagles (2 years old; weighing approximately 10 kg) obtained from Hamaguchi Animal (Osaka, Japan). The animals were housed in a temperature-controlled environment at 24 °C with free access to food and water. The body weight and general health of the animals were monitored throughout the study. (cid:696)- T C P p a r t i c l e t r a n s p l a n t a t i o n The dogs underwent bilateral sinus floor augmen tation surgeries and were randomly divided into two groups depending on the type of repair: The experimental group received a porous (cid:696)-TCP and tapered titanium (Ti) implant (NovelActive, Nobel Biocare Japan, Tokyo, Japan), and the control group received the Journal of Oral Science & Rehabilitation Volume 3 | Issue 1/2017 45

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