Polymeric-Calcium Phosphate Cement Composites-Material Properties: In Vitro and In Vivo Investigations

New polymeric calcium phosphate cement composites (CPCs) were developed. Cement powder consisting of 60 wt% tetracalcium phosphate, 30 wt% dicalcium phosphate dihydrate, and 10 wt% tricalcium phosphate was combined with either 35% w/w poly methyl vinyl ether maleic acid or polyacrylic acid to obtain CPC-1 and CPC-2. The setting time and compressive and diametral tensile strength of the CPCs were evaluated and compared with that of a commercial hydroxyapatite cement. In vitro cytotoxicity and in vivo biocompatibility of the two CPCs and hydroxyapatite cement were assessed. The setting time of the cements was 5–15 min. CPC-1 and CPC-2 showed significantly higher compressive and diametral strength values compared to hydroxyapatite cement. CPC-1 and CPC-2 were equivalent to Teflon controls after 1 week. CPC-1, CPC-2, and hydroxyapatite cement elicited a moderate to intense inflammatory reaction at 7 days which decreased over time. CPC-1 and CPC-2 show promise for orthopedic applications

The Effect Of Filler Addition On Biaxial Flexure Strength And Modulus Of Commercial Dentin Bonding Systems.

To evaluate the effects of filler addition on the biaxial flexural strength and modulus of two commercial adhesive systems. The systems were either unfilled (Adper Single Bond [3M ESPE] and Prime and Bond 2.1 [Dentsply]) or filled (Adper Single Bond Plus [3M ESPE] and Prime and Bond NT [Dentsply]). Resin disks of each product (0.6 mm thick and 6.2 mm in diameter) were prepared in Teflon molds (n = 11 each group; 44 in total). The adhesive solutions were light activated with a halogen light-curing unit. The disks were stored dry in the dark 24 hours before biaxial flexural testing in a universal testing machine until fracture (1.27 mm/minute; model 5844, Instron). Data were statistically analyzed by one-way ANOVA and Tukey post hoc test at a preset alpha of 0.05. Flexural strength values (MPa) (SD) were Single Bond 62 (16); Single Bond Plus 46 (15); Prime and Bond 59 (13); and Prime and Bond NT 85 (16). The flexural moduli (MPa) (SD) were Single Bond 1,026 (241); Single Bond Plus 1,180 (188); Prime and Bond 744 (146); and Prime and Bond NT 1,539 (267). Based on the results, Prime and Bond NT (filled) exhibited higher flexural strength and modulus than Prime and Bond (unfilled), while no significant difference in both parameters was noted between Single Bond and Single Bond Plus. Filler addition to bonding agents can increase the flexural strength and modulus; however, results are product dependent.42e39-4

Silorane- and high filled-based"low-shrinkage" resin composites: shrinkage, flexural strength and modulus

This study compared the volumetric shrinkage (VS), flexural strength (FS) and flexural modulus (FM) properties of the low-shrinkage resin composite Aelite LS (Bisco) to those of Filtek LS (3M ESPE) and two regular dimethacrylate-based resin composites, the microfilled Heliomolar (Ivoclar Vivadent) and the microhybrid Aelite Universal (Bisco). The composites (n = 5) were placed on the Teflon pedestal of a video-imaging device, and VS was recorded every minute for 5 min after 40 s of light exposure. For the FS and FM tests, resin discs (0.6 mm in thickness and 6.0 mm in diameter) were obtained (n = 12) and submitted to a piston-ring biaxial test in a universal testing machine. VS, FS, and FM data were submitted to two-way repeated measures and one-way ANOVA, respectively, followed by Tukey's post-hoc test (a = 5%). Filtek LS showed lower VS than did Aelite LS, which in turn showed lower shrinkage than did the other composites. Aelite Universal and Filtek LS exhibited higher FS than did Heliomolar and Aelite LS, both of which exhibited the highest FM. No significant difference in FM was noted between Filtek LS and Aelite Universal, while Heliomolar exhibited the lowest values. Aelite LS was not as effective as Filtek LS regarding shrinkage, although both low-shrinkage composites showed lower VS than did the other composites. Only Filtek LS exhibited FS and FM comparable to those of the regular microhybrid dimethacrylate-based resin composite