I have heard so many times that babies who are teething refuse to nurse. On another hand, my dd was always more interested in nursing when she was cutting a new tooth. It really depends on a baby. But I agree, many of them won't nurse because their gums are swallen and supersensitive and they don't feel comfortable while nursing.
You can offer some chilled rubber teethers in meantime and keep offering breast, but don't force a baby to nurse, he may get aversion to your breast. If you are worried about his milk intake, try to nurse when he is sleeping, they are way more relaxed then and willing to accept feeding.