Always thought that babies "teething" are more likely to be needing more sleep or are unsettled about something else. There have been studies done to show that teething if it does cause pain is mild and lasts only for a day or two.
"Let’s start with the oft-cited claim that teething causes excruciating pain because a tooth is “stabbing” through the gum. “That’s one of those myths,” explains Clay Jones, a pediatric and newborn hospitalist at Newton-Wellesley Hospital in Newton, Massachusetts, who wrote about teething for the popular blog Science-Based Medicine. “What happens is that the gums remodel—they move out of the way as the tooth emerges.” After all, Jones says, gums don’t bleed when kids teethe. A 2003 study documented a statistically significant increase in one inflammatory marker during infant teething, but the rest of the markers the study tested, called cytokines, didn’t change much. “A baby might be in pain or having some degree of discomfort, but I think that a significant amount of pain is not likely or plausible,” Jones says.
Indeed, if teething caused tremendous pain, one would expect kids to have consistent symptoms—but they don’t. In one of the most carefully conducted studies on teething that’s ever been done, researchers in Brazil sent dentists into the homes of 47 babies every day for eight months. They took the babies’ temperatures, checked their gums, and interviewed the parents about their infants’ behaviors. The study found that teething was associated with sleep disturbances, drooling, rashes, runny noses, diarrhea, appetite loss, irritability, and slight rises in temperature (not clinical fevers). But the interesting thing is that these symptoms consistently occurred only on the day that a child’s tooth erupted and one day after. No symptoms regularly occurred in the days before the tooth appeared."