There are only three studies in PubMed that mention CrissCross bristle design explicitly.
The first, authored by Oral-B Laboratories, finds that "comparisons with more than 80 leading manual toothbrushes from around the world demonstrate a consistent, significant advantage for the new CrossAction toothbrush, both with respect to interproximal penetration and cleaning effectiveness."1
The second compares five manual toothbrushes of different bristle design and finds that CrissCross bristle design "demonstrated statistically significantly better plaque removal." It is also significant that the study was written BioSci Research, self described as "Independant [sic] Evaluation of Oral Health Care Products"--a for-profit lab that frequently endorses Oral-B products in their studies.2
The third, and the only legitimate-looking of the three (since it comes from an actual academic department), finds no difference between a power brush with a static CrissCross component and a manual toothbrush (made by Butler Gum).3
- Beals, Ngo, et. al. "Development and laboratory evaluation of a new toothbrush with a novel brush head design." Am J Dent. 2000 Mar;13(Spec No):5A-14A.
- "A clinical evaluation of the plaque removal efficacy of five manual toothbrushes" published in the Journal of Clinical Dentistry 2010;21(1):8-12.
- "Evaluation of several brushing motion combinations in relation to plaque-removing efficacy with Oral-B CrossAction Power: a professional brushing study." Int J Dent Hyg. 2006 Nov;4(4):204-8.
Please note that this answer does not constitute medical advice. It is only meant to summarize published research related to the topic and limited to the cited sources. Consult your physician about what these results may mean for your health.