Teething is the process by which an infant's teeth sequentially appear by breaking through the gums. Teething may start as early as three months or as late, in some cases, as twelve months. The typical time frame for new teeth to appear is somewhere between six and nine months. It can take up to several years for all 20 deciduous (aka "baby" or "milk") teeth to emerge. Though the process of teething is sometimes referred to as "cutting teeth", when teeth emerge through the gums they do not cut through the flesh. Instead, special chemicals are released within the body that cause some cells in the gums to die and separate, allowing the teeth to come through.

Sequence of appearance

..5 days later that incisor is visible.

The infant teeth tend to emerge in pairs - first one lower incisor emerges then the other lower incisor emerges before the next set begin to emerge. The general pattern of emergence is:

1. Lower central incisors (2) at approximately 6 months
2. Upper central incisors (2) at approximately 8 months
3. Upper lateral incisors (2) at approximately 10 months
4. Lower lateral incisors (2) at approximately 10 months
5. First molars (4) at approximately 14 months
6. Canines (4) at approximately 18 months
7. Second molars (4) at approximately 2-3 years

Milk teeth tend to emerge sooner in females than in males. The exact pattern and initial starting times of teething appear to be hereditary. When and how teeth appear in an infant has no bearing on the health of the child.

Teething symptoms

The level of pain that a baby can handle will be different for each child. Some may be a lot fussier than others while they are teething. The soreness and swelling of the gums before a tooth comes through is the cause for the pain and fussiness a baby experiences during this change. These symptoms usually begin about three to five days before the tooth shows, and they disappear as soon as the tooth breaks the skin.  Some babies are not even bothered by teething.

Common symptoms include drooling or dribbling, mood changes and feelings of irritability or crankiness and swollen gums. Crying, sleeplessness, restless sleep at night, and mild fever are also associated with teething. Teething can begin as early as 3 months and continue until a child's third birthday.  In rare cases, an area can be filled with fluid and appears over where a tooth is erupting and cause the gums to be even more sensitive. Pain is often associated more with large molars since they cannot penetrate through the gums as easily as the other teeth.

Some of the signs or symptoms that a baby has entered the teething stage will be actions that are noticeable. They may chew on their fingers or toys to help relieve pressure on their gums. Babies might refuse to eat or drink due to the pain. Symptoms will generally fade on their own, but a doctor should be notified if they worsen or are persistent. Teething may cause signs and symptoms in the mouth and gums, but it doesn't cause problems elsewhere in the body. 

Pulling on the ears is another sign of pain; the pain in the mouth throbs throughout the baby's head so they pull their ears believing that it will provide relief. Mild rash can develop around the mouth due to skin irritation that is caused because of excessive drooling or dribbling. 

Teething has not been shown to cause fever or diarrhea. A slight rise of temperature may occur when the teeth come through the gum, but this does not make a baby ill.