Dagmar loooved rusks when she was teething, and I shamefacedly admit I loved them too because I could give her one instead of making her cereal, so it eased the burden for me a bit. I never had any problems with them, I actually didn't like the harder US teething biscuits because they could break into hard choking pieces, whereas rusks sort of dissolved in her mouth. But every baby is different!
We were lucky, she was a very easy teether-but the only thing that worked for her was Motrin and her dummy, she didn't like/use any teething toys and she really didn't like anything cold or frozen.