The Effect of Composite Cement (ECC) as A High Performance Fiber Reinforced Composite Cement

Composite Cement (ECC) addresses a special type of high performance fiber reinforced composite cement with high tensile ductility. Fibers have been used to increase the toughness of quasi-brittle cement-based materials. As a result of its ability to produce high tensile ductility, ECC originally designed its strain-hardening behavior using a micromechanical concept, so that over-tensile strain capacity could be achieved in excess of 2% through multiple cracks. This research method is carried out by means of laboratory testing in accordance with data from literature studies both Indonesian SK SNI Standards and foreign standards, namely ASTM. The method applied in this research is an experimental method. The independent variable in this study is the reinforcement with the addition of fiber to the PVA ECC material mix, while the dependent variable in this study is the compressive strength value and the magnitude of the elastic modulus of the PVA ECC material. The results of the tensile strength of the ECC PVA material obtained on average at the age of 7, 14 and 28 days were 3.108 MPa, 3.547 MPa and 4.34 MPa, respectively. The tensile strength of the ECC PVA material increases with age. The average modulus of elasticity of PVA ECC material obtained at the age of 7, 14 and 28 days was 18763.02 MPa, 20788.81 MPa and 21060.03 MPa, respectively. Based on the modulus of elasticity, it also increases with the increase in compressive strength.

Better Glass-fiber Post Preservation in Teeth with Ferrule When Subjected to Chewing

SUMMARY Objectives: To evaluate the influence of ferrule effect and mechanical fatigue aging on glass-fiber post push-out bond strength (PBS) to root-canal dentin at different root thirds of premolars. Methods and Materials: Thirty-two sound maxillary premolar teeth were collected, and randomly assigned to two experimental groups (n=16): ‘Remaining Dentin Ferrule’ (RDF) = coronal crown cut 2.0 mm above the cemento-enamel junction (CEJ); ‘Without Dentin Ferrule’ (WDF) = coronal crown cut at the cemento-enamel junction. Teeth were endodontically treated, post spaces were prepared up to 10.0-mm depth from CEJ, and glass-fiber posts were cemented using a dual-cure self-adhesive composite cement. Standardized cores were built using a light-cure composite, upon which tooth cores were prepared using a 1.5-mm taper ogival-end diamond bur. Crowns were handmade using self-cure acrylic resin and cemented using the aforementioned composite cement. Half of the specimens were subjected to 1,200,000 cycles of mechanical fatigue in a chewing simulator (F = ‘Fatigue’), while the other half were stored in distilled water at 37°C for 1 week (C = ‘Control’). All specimens were horizontally sectioned into 1.0-mm thick slices prior to PBS test; the failure modes were assessed using stereomicroscopy and scanning electron microscopy (SEM). Data were analyzed for each root third using two-way analysis of variance (ANOVA) followed by Tukey HSD post-hoc test; frequency distribution was compared by Chi-square test (α=0.05) and post-hoc comparisons with Bonferroni. Results: The mean PBS in MPa (SD) were = RDF_F = 10.4 (2.9); WDF_F = 6.9 (1.7); RDF_C = 14.5 (2.7); WDF_C = 14.2 (2.9). Similar PBS were found for the root thirds. For all root thirds, significant differences were found for both the factors Dentin Ferrule and Fatigue, and their interaction (p<0.05). The lowest PBS was found for specimens without dentin ferrule subjected to chewing fatigue (p<0.001). Most failures occurred at the composite cement/dentin interface, followed by mixed and composite cement/glass-fiber post interfacial failures. There was a significant increase in mixed failures for the WDF_F group (p<0.001). Conclusion: Absence of 2.0-mm remaining dentin ferrule in premolars resulted in a higher decrease of the glass-fiber posts’ PBS to dentin after mechanical fatigue, irrespective of root third.

Comparative evaluation of polymethylmethacrylate and composite bone cements. Review of the experimental studies results

Current article is a review of experimental studies of different bone cements types and their combinations. Providing of bone fragments stable fixation at osteosynthesis in cases of difficult multifragmental fractures, arthroplasties and other implants using especially in the osteoporosis conditions is a main task of orthopaedic surgery procedures. Polymethylmethacrylate (PMMA) is the first material that is answered to these requirements. The evolution of bone cements resulted in creation of a new composite substance — combination of PMMA and β-threecalciumphosfates (β-TCPh). Combination of these two components allowed to provide high bioabsorbal, osteoconductive and osteointegrative properties along with sufficient durability. In the analyzed works the properties of composite cement CalCemex were evaluated in vivo experiment. It was found that in the case of PMMA penetration of bone tissue into the polymer structure did not occur. Under the conditions of using bone cement with β-TCF admixture, the formation of bone tissue was observed not only on the surface of the implant, but also in the external and internal pores. It is the presence of pores in CalCemex that the authors explain the possibility of penetration of cellular elements, blood vessels and bone formation. Moreover, β-TCPh is included into this material and it is bioresorbed by osteoclasts. This leads to the release of calcium and phosphorus ions and, consequently, simplifies the attachment of the newly formed bone to the bone cement. We assume that composite cement like CalCemex type is a promising material for the treatment of various types of fractures and replacement of bone defects. It should be mentioned that research in this area is ongoing and intensive work is underway to synthesize and study the results of clinical application of composite bone cements with maximum bioactive properties that will not only strengthen bone tissue but also perform osteointegrative function. Key words. Bone cement, polymethylmethacrylate, β-threecalciumphosfates, experiment.