When does teething start? Probably not as early as people think. (Schedule of normal tooth eruption) At the four month checkup, I'm always asked if the baby is teething because she puts everything in her mouth and slobbers all over the place. This is just normal development - by four months babies are learning to put their hands together at the midline, grasp, and bring whatever they grab to the mouth for oral exploration. Yes, sometimes infants get teeth before six months but that doesn't change much. Some babies wait until a year to erupt teeth, but they all start drooling and chewing at four months.
How much does teething hurt? I can't remember myself. Parents imagine it must be dreadful, judging by all the teething nostrums they buy. If the gum isn't really red or painful-appearing, I tend to doubt it hurts much, if at all. Most of the time teeth just appear one day and nobody really noticed any great struggle on baby's part to "birth" the tooth. If some teeth supposedly hurt so much, how come so many more teeth cause nary a whimper? Those certainly were larger teeth! My sons erupted 80 deciduous ("baby") teeth among them. I don't think we took note of more than one or two of them as possibly causing discomfort. The symptom of night waking and crying in the eight or nine month old infant commonly attributed to "terrible teething pain" is really trained night waking in a child habitually rocked or nursed to sleep (those folks need a good video 8-).
Ask yourself this question: if teething hurts so darn much when the child is small, why is it that when he erupts permanent teeth - larger teeth, to be sure - he will never complain about gum pain? Hmmm...
How important is it when the teeth come in, by six months or nine months, or whatever? Again, much ado about nothing. The doctor's rule of thumb is, at least one tooth by 12 to 15 months, and all is well with the child. They always come in, and if they are late, probably several will come in at once. Hormonal deficiencies, for example low thyroid or low growth hormone can cause delayed eruption of the teeth - but those problems would be noticed long, long before the delay in tooth eruption was noticed. I've never seen, heard of, or even read in the medical literature about a child in whom when the teeth erupted made a medical, diagnostic difference.
So what actual symptoms does teething cause? Maybe some fussiness, certainly a lot of gnawing on everything in sight, slobbering all over everything... but NOT: fever, runny nose, diarrhea. Those are all symptoms of infection. "But everybody says their child...." or "But I know my child ALWAYS gets a fever when he cuts a tooth..." Well, statistically we expect that between 6 months and 30 months the child will get 1) twenty little infections - colds, gastroenteritis with diarrhea, viral infections with fever, and 2) twenty teeth. It is not unexpected that often the tooth and the sniffles will be closely associated in time. That doesn't mean one causes the other. Sorry. Every so often I see a child with fairly serious illness - pneumonia, or kidney infection - whose parents say "He had a fever of 104º but we just thought it was teething, so we didn't call..." So this isn't a trivial discussion.
Once in a while a pocket of hemorrhage will appear on the gum - a dark, bluish colored firm knot where an erupting tooth has worked its way through a blood vessel. This is harmless and probably painless. It can be left alone to rupture by itself, or Mother may massage it a bit with her finger. Your choice. Parents may also discover a tiny, round, firm white knot on the gum which they think is a tooth in a very young infant. This is actually an epithelial (skin) cyst. It will rupture and disappear soon of its own accord.
Various topical anesthetic gum preparations are sold for the treatment of the
scourge of teething. They are generally harmless, if not totally useless. Use them if you feel you must. The ones containing benzocaine make the most sense;
some teething remedies are mostly alcohol, which may burn on
application to the gum and generally doesn't make a lot of sense
for use in young infants.