Setting Time, Handling Property and Mechanical Strength Evaluation of SCPC50 and Apatite Cement Mixture in Various Combinations

Apatite cement is ideal self-setting cement for bone substitute material, however its use is limited only to areas that receive minimum load bearing because mechanical strength of apatite cement is low. Silica-calcium phosphate nanocomposite (SCPC50) is material having good mechanical strength and has an important role in bone remodeling (bone metabolism), mineralization, synthesis of cartilage, collagen production, proliferation and differentiation of bone cells. However, the unsetting and granule’s physical shape of SCPC50 limits the application. The purpose of this study is to determine the effect of various mixtures of SCPC50 and apatite cement to manipulative index (setting time and handling property), and mechanical properties. The experimental results show that the setting time of apatite cement mixture with 5% and 10% SCPC50 was 40% higher (p<0.05). The mechanical strength evaluated by Diametral Tensile Strength showed that the addition of both 5% silica and 10% SCPC50 composition to apatite cement mixture increased the mechanical strength of apatite cement mixture (p<0.1). The handling property of cement paste was significantly increased between the apatite cement without SCPC50 and apatite cement with both 5% SCPC50 and 10% SCPC50 (p<0.05). It is concluded that the addition of SCPC50 to apatite cement mixture could improve the mechanical properties and it is expected to improve its bioactivity.

Diametral Tensile Strength Evaluation of Carbonate Apatite Cement Reinforced by Genipin Cross-Linked Gelatin

Carbonate apatite is one of the most widely studied bioceramic material for its use as bone cement. On the previous study, it has already stated that CO3Ap cement has good osteoconductivity which makes this cement could be replaced by bone. However, the mechanical strength of CO3Ap cement is still low. This low mechanical strength is estimated due to the high porosity and absence of organic components. The aim of this study is to improve the mechanical strength of the CO3Ap cement reinforced by gelatin as an organic component with genipin as a cross-linking agent (Gelapin). The powder phase of vaterite and DCPA at weight ratio 40:60 were mixed with 0.2 mol/L Na2HPO4, 5% (w/v) gelatin, and 20% (v/v) genipin using 0.5 liquid to powder (L/P) ratio. The liquid phase ratios of Na2HPO4 and Gelapin were 50:50, 70:30, and 90:10. For control group, Gelapin were didn’t mixed in the liquid. Diametral tensile strength was improving and statistically significant (p<0.05) on set cement with 50:50 liquid ratio, the average value was 6.02 ± 0.14 MPa whereas the average value of the control group was only 3.10 ± 0.15 MPa. For this instance, gelatin serves a polymer matrix so the carbonate apatite crystallites could be well distributed within it which then gives more flexibility and resistance for the cement. On the other hand, genipin was also successfully cross-linked the gelatin. This study showed that by reinforcing CO3Ap cement using genipin cross-linked gelatin might be a good candidate for a bone substitute material.

Biocompatibility of Hydrophilicity Improved Apatite Cement

Hydrophilicity of apatite cement was increased after O3 gas treatment on apatite cement (AC) powder. It results on the improvement of the handling and mechanical properties of set AC. Behavior of osteoblastic cells to O3-treated set AC was evaluated including initial cell attachment, morphology of the attached cells and proliferation using rat bone marrow cell (RBM). Cells’ response to the set AC was the same regardless of O3 treatment. The cells well attached and spread with filopodial extensions even over the O3-treated set AC specimens. The rates of cell proliferation on set AC were also the same regardless of O3 treatment. The result indicated O3 treatment of AC powder would not affect to the osteoblast cell response of set AC.

Modification of surface hydrophilicity of dental materials by ozone

Introduction: Gypsum, Portland, and apatite cement, and gypsum have been developed as dental materials for a long time. Similarity of the three materials leads to some relevant approaches to improve the characteristic of dental materials. Water reducing agent is commonly used in detergent or soap and also used as a conventional method in the cement industry to increase the handling and mechanical property. Cement paste mixed with water reducing agent is more flowable (ease handling), and the set mass is harder (mechanical property increased). However, it has a problem with biomaterial cement due to the biocompatibility. This water reducing agent is harmful to living tissue. Therefore, a new approach will be demonstrated in this research. Methods: In this study, the hydrophilicity of cement powder was modified by ozone gas treatment. Ozone gas treatment will be applied to modify the hydrophilicity of cement particles; therefore, it can act similar to the water reducing agent. Results: The hydrophilicity of gypsum, Portland, and apatite cement powder was significantly increased after ozone gas treatment. The hydrophilicity improvement of cement powder increased the ability of water to interact with the cement powder. The benefit is the flowability improvement of cement paste. Therefore, the manipulation index would also be increased. The mechanical property would be increased because the water added for manipulation was decreasing. Conclusion: Ozone gas treatment could improve the hydrophilicity of gypsum, Portland, and apatite cement powder.Keywords: Gypsum, Portland, apatite cement, hydrophilic, ozone

The Evaluation of Setting Time and FTIR Spectroscopy of Carbonate Apatite Cement as Endodontic Sealer

The carbonate apatite (CO3Ap) cement as an endodontic sealer play an essential role for endodontics treatment due to its potential to obturate root canal system as one of the most important part in endodontic treatment. Moreover, the CO3Ap has probability of similarities with composition of root dentin. Recently, the setting time of commercial endodontic sealer has 4 hours to 1 day. Therefore, the aim of this present study is to evaluate setting time and to determine the functional group of the new material composition for endodontic sealer. CO3Ap cement sealer was prepared by mixing dicalcium phosphate anhydrous (DCPA), vaterite and calcium hydroxide [Ca (OH)2] with 0.2 mol/L Na2HPO4 containing 1% sodium carboxymethylcellulose (NaCMC) and 32 μg thymoquinone, with liquid to powder ratio of 0.6. The setting time was evaluated by Vicat needle method as describe on modification ISO 1566 for zinc phosphate cement. Five compositions of powder ratio were prepared in this study. The set CO3Ap cement sample was evaluated by Fourier Transform Infrared Spectroscopy (FTIR) to define the functional group of the sample. Setting time evaluation indicated that the average setting time of CO3Ap cement was 21 minutes of five compositions. The FTIR analyses revealed that the CO32- groups were detected, so the results could determine as B-type CO3Ap.The CO3Ap cement was considered fast setting as an endodontic sealer compared to sealers made from other base and proven to have similarities with the components of root dentin.

Setting time evaluation of injectable carbonate apatite cement using various sodium carboxymethylcellulose (Na CMC) concentration

Introduction: The injectable calcium phosphate cement has the advantage to be used in the bone defect with the limited access which supports a minimally invasive surgical technique. These Injectability properties of calcium phosphate cement can be modified by adding a sodium carboxymethylcellulose (Na CMC). The aim of this present study is to investigate the setting time of injectable bone cement based on CO3Ap using various Na CMC concentration. Methods: Vaterite (a polymorph of CaCO3) and Dicalcium Phosphate Anhydrous (DCPA) as powder phase mixed with 0.2 mol/L Na2HPO4 solution containing 1% polyethylene glycol (PEG) and various concentration of Na CMC as followed 0.5%, 1%, 1.5%, and 2%, respectively. Each concentration groups was consisting of 5 samples from total 20 samples. Powder and liquid phase was mixed with a spatula at a liquid to powder (L/P) ratio of 0.4. The setting time of CO3Ap cement was evaluated according to the modification method standardized by ISO 1566 for dental zinc phosphate cement using a custom fabricated Vicat needle apparatus. The cement was maintained at 37ºC and 100% relative humidity as a standard requirement. Results: The mean value of setting time cement was as followed 0.5% Na CMC 35:06 minutes, 1% Na CMC 38:48 minutes, 1.5% Na CMC 40:06 minutes, and 2% Na CMC 41:30 minutes. The result is statistically significant (p<0.05) with the group of 0.5% Na CMC compared to others group. Conclusion: Increasing the concentration of Na CMC could prolong the setting time of CO3Ap cement.

Hardness Evaluation of Carbonate Apatite Cement Based on Various Ratio of Precursor

Carbonate Apatite (CO3Ap) cement is considered as an ideal bone substitute due to its biocompatibility and osteoconductivity. Also, CO3Ap cement has the chemical composition that closes to natural bone. During cement preparation, precursors play an important role that affects the properties of CO3Ap cement. Cement hardness is one of the important properties that need to be evaluated before the obtained cement can be applied as a bone substitute. Therefore, the purpose of this study is to determine the effect of precursor ratio of CaCO3 and CaHPO4 on the hardness level of CO3Ap cement. In the present study, the CO3Ap cement was prepared from CaCO3 and CaHPO4. Both Commercial and synthesized CaCO3 were used. The CO3Ap cement obtained from commercial CaCO3 was used as a control group. Synthesized CaCO3 was obtained from Indonesian natural limestone. Three different CaCO3:CaHPO4 ratios, 40:60, 30:70 and 20:80 were mixed with 1 mol/L Na2HPO4. Samples were kept at 37°C with 100% relative humidity for 24 hours then tested using micro Vickers hardness testing machine. The micro Vickers hardness of the control group with CaCO3:CaHPO4 ratio of 40:60, 30:70 and 20:80 were 5.09 VHN, 6.34 VHN, and 6.73 VHN, respectively. Meanwhile, the micro Vickers hardness of the CO3Ap cement obtained from synthesized CaCO3 were 6.22 VHN, 7.50 VHN, and 10.37 VHN for the CaCO3:CaHPO4 ratio of 40:60, 30:70 and 20:80, respectively. The micro Vickers hardness level of CO3Ap cement precursor ratio from the lowest to the highest was 40:60 < 30:70 < 20:80. In conclusion, the precursor ratio significantly affects the hardness level of the CO3Ap cement. The hardness level of CO3Ap cement obtained from synthesized CaCO3 was higher compared with that obtained from commercial CaCO3.