I'm not aware of any quantitative research specifically relating to pornography and sexting. There's certainly qualitative research that suggests a strong connection.
Quantitatively, it is clear that pornography and, in general, sexualized media have a strong influence on how youth view sex and sexuality. Connections have been drawn between pornography and acceptance of rape myths, but a lot of this is not restricted to pornography. A lot of the evidence has shown that you get the same effects from any kind of sexualized media, and that it is not the sexuality, not the sexual element of pornography, that is the problem, but the stereotyped and, in particular, one might say patriarchal forms of sexuality that are on display in so many forms of sexualized media—and that again is why media literacy is an essential partner to digital literacy in addressing these issues.