Pooling of dentin microtensile bond strength data improves clinical correlation.

Purpose: To evaluate whether the correlation between in vitro bond strength data and estimated clinical retention rates of cervical restorations after two years depends on pooled data obtained from multicenter studies or single-test data. Materials and Methods: Pooled mean data for six dentin adhesive systems (Adper Prompt L-Pop, Clearfil SE, OptiBond FL, Prime & Bond NT, Single Bond, and Scotchbond Multipurpose) and four laboratory methods (macroshear, microshear, macrotensile and microtensile bond strength test) (Scherrer et al, 2010) were correlated to estimated pooled two-year retention rates of Class V restorations using the same adhesive systems. For bond strength data from a single test institute, the literature search in SCOPUS revealed one study that tested all six adhesive systems (microtensile) and two that tested five of the six systems (microtensile, macroshear). The correlation was determined with a database designed to perform a meta-analysis on the clinical performance of cervical restorations (Heintze et al, 2010). The clinical data were pooled and adjusted in a linear mixed model, taking the study effect, dentin preparation, type of isolation and bevelling of enamel into account. A regression analysis was carried out to evaluate the correlation between clinical and laboratory findings. Results: The results of the regression analysis for the pooled data revealed that only the macrotensile (adjusted R2 = 0.86) and microtensile tests (adjusted R2 = 0.64), but not the shear and the microshear tests, correlated well with the clinical findings. As regards the data from a single-test institute, the correlation was not statistically significant. Conclusion: Macrotensile and microtensile bond strength tests showed an adequate correlation with the retention rate of cervical restorations after two years. Bond strength tests should be carried out by different operators and/or research institutes to determine the reliability and technique sensitivity of the material under investigation.

A-1 Monthly Public Assistance Statistical Report Family Investment Program, December 2003

Monthly Public Assistance Statistical Report Family Investment Program

Tensile strength characteristics of polypropylene composites reinforced with stone groundwood fibers from softwood

The behavior of stone groundwood / polypropylene injection-molded composites was evaluated with and without coupling agent. Stone groundwood (SGW) is a fibrous material commonly prepared in a high yield process and mainly used for papermaking applications. In this work, the use of SGW fibers was explored as a reinforcing element of polypropylene (PP) composites. The surface charge density of the composite components was evaluated, as well as the fiber’s length and diameter inside the composite material. Two mixing extrusion processes were evaluated, and the use of a kinetic mixer, instead of an internal mixer, resulted in longer mean fiber lengths of the reinforcing fibers. On the other hand, the accessibility of surface hydroxyl groups of stone groundwood fibers was improved by treating the fibers with 5% of sodium hydroxide, resulting in a noticeable increase of the tensile strength of the composites, for a similar percentage of coupling agent. A new parameter called Fiber Tensile Strength Factor is defined and used as a baseline for the comparison of the properties of the different composite materials. Finally the competitiveness of stone groundwood / polypropylene / polypropylene-co-maleic anhydride system, which compared favorably to sized glass-fiber / polypropylene GF/PP and glass-fiber / polypropylene / polypropylene-co-maleic anhydride composite formulations, was quantified by means of the fiber tensile strength factor

E-1 Monthly Statistical Movement Summary for Entire Iowa Department of Corrections, Iowa Department of Corrections, February 2001

Monthly Statistical Movement Summary for Entire Iowa Department of Corrections

E-1 Monthly Statistical Movement Summary for Entire Iowa Department of Corrections, Iowa Department of Corrections, May 2001

Monthly Statistical Movement Summary for Entire Iowa Department of Corrections

E-1 Monthly Statistical Movement Summary for Entire Iowa Department of Corrections, Iowa Department of Corrections, April 2001

Monthly Statistical Movement Summary for Entire Iowa Department of Corrections

E-1 Monthly Statistical Movement Summary for Entire Iowa Department of Corrections, Iowa Department of Corrections, May 2001

Monthly Statistical Movement Summary for Entire Iowa Department of Corrections

E-1 Monthly Statistical Movement Summary for Entire Iowa Department of Corrections, Iowa Department of Corrections, June 2001

Monthly Statistical Movement Summary for Entire Iowa Department of Corrections

E-1 Monthly Statistical Movement Summary for Entire Iowa Department of Corrections, Iowa Department of Corrections, July 2001

Monthly Statistical Movement Summary for Entire Iowa Department of Corrections

E-1 Monthly Statistical Movement Summary for Entire Iowa Department of Corrections, August 2001

Monthly Statistical Movement Summary for Entire Iowa Department of Corrections

E-1 Monthly Statistical Movement Summary for Entire Iowa Department of Corrections, September 2001

Monthly Statistical Movement Summary for Entire Iowa Department of Corrections

E-1 Monthly Statistical Movement Summary for Entire Iowa Department of Corrections, Iowa Department of Corrections, November 2001

Monthly Statistical Movement Summary for Entire Iowa Department of Corrections

E-1 Monthly Statistical Movement Summary for Entire Iowa Department of Corrections, Iowa Department of Corrections, November "A" 2001

Monthly Statistical Movement Summary for Entire Iowa Department of Corrections

E-1 Monthly Statistical Movement Summary for Entire Iowa Department of Corrections, Iowa Department of Corrections, December 2001

Monthly Statistical Movement Summary for Entire Iowa Department of Corrections

E-1 Monthly Statistical Movement Summary for Entire Iowa Department of Corrections, Iowa Department of Corrections, January 2002

Monthly Statistical Movement Summary for Entire Iowa Department of Corrections