Teething is the process of baby teeth pushing through the gums, and it involves far more biology than most parents realize. Teeth don’t simply slide upward through soft tissue. They actively remodel bone, dissolve connective tissue, and break through the gum surface over the course of months. The process typically begins around 6 months of age and continues until roughly age 3, when all 20 primary teeth have emerged.
What Happens Inside the Jaw
Each baby tooth forms inside its own small pocket of bone in the jaw, called a bony crypt. Surrounding the developing tooth is a specialized layer of tissue called the dental follicle. This tissue is the real engine behind teething. It releases signaling molecules that coordinate two opposing activities at the same time: bone breakdown above the tooth and bone growth below it.
The top half of the dental follicle triggers the production of cells that dissolve bone, clearing a path upward through the jaw. It does this by releasing a key signaling protein that activates bone-dissolving cells at much higher levels near the crown of the tooth than near the base. Meanwhile, the bottom half of the follicle stimulates new bone formation beneath the tooth, creating an upward push. This combination of clearing from above and building from below is what moves the tooth toward the surface.
As the tooth nears the gum line, the follicle also breaks down the connective tissue between the bone and the gum surface. Once the tooth pierces through the gum tissue, it continues to emerge slowly until it reaches its full height and makes contact with the opposing tooth.
Which Teeth Come In First
Teeth generally follow a predictable sequence, though there’s a wide range of normal timing. According to the American Academy of Pediatric Dentistry, many otherwise normal infants don’t follow the stated schedule exactly, so a few months of variation in either direction is common.
The lower central incisors (the two bottom front teeth) are usually first, arriving between 5 and 8 months. The upper central incisors follow at 6 to 10 months. From there, the remaining front teeth fill in: upper lateral incisors between 8 and 12 months, and lower lateral incisors between 7 and 10 months.
The first molars arrive between 11 and 18 months, followed by the canines (the pointed teeth between the front teeth and the molars) at 16 to 20 months. The second molars come in last, between 20 and 30 months. By around age 2.5 to 3, most children have a full set of 20 primary teeth.
What Teething Actually Feels Like for Babies
The symptoms parents most reliably see during teething are mild and localized: irritability, increased drooling, and red or swollen gums at the eruption site. These make sense given the biology. The gum tissue is being stretched and broken from underneath, which triggers a mild inflammatory response right at the surface.
What teething does not cause is high fever or diarrhea. These are among the most common misconceptions. A structured review of the clinical evidence found no credible link between teething and significant fevers or gastrointestinal problems. A very slight rise in temperature can occur, but a true fever (above 100.4°F) warrants attention as an illness, not dismissal as teething. Attributing serious symptoms to teething can delay the recognition of actual infections, which happen to peak during the same age range because maternal antibodies are waning.
Eruption Cysts
Occasionally, fluid collects between the tooth and the gum tissue as a tooth pushes upward, forming a small dome called an eruption cyst. These look like a bluish or clear bump on the gum, most commonly toward the back of the lower jaw. They’re usually painless, and the bump itself may be the only visible sign.
In most cases, eruption cysts resolve on their own once the tooth breaks through. However, if the bump bleeds, oozes pus, causes pain when chewing, or lasts longer than two weeks, it’s worth having a dentist take a look. Cysts that persist beyond a month may need a minor procedure to help the tooth come through.
Safe Ways to Ease Discomfort
The American Academy of Pediatrics recommends two straightforward approaches: rubbing your baby’s gums with a clean finger, and giving them a teething ring made of firm rubber to chew on. Gentle pressure on the gum counteracts the sensation of pressure from below, which is why babies instinctively want to bite down on things during active eruption. The teething ring should not be frozen. A too-hard or frozen object can actually bruise the already-irritated gums and make things worse. Chilled (not frozen) is fine.
Products to Avoid
The FDA has issued direct warnings against using numbing gels or creams containing benzocaine or lidocaine on teething babies. These products offer little to no benefit for teething pain and carry serious risks. Benzocaine can trigger a condition where red blood cells lose their ability to carry oxygen effectively. Lidocaine solutions can cause seizures, heart problems, and severe brain injury in infants if too much is applied or accidentally swallowed. Both have been linked to infant deaths.
Homeopathic teething tablets fall under the same warning. The FDA has found that some of these products contain inconsistent amounts of active ingredients, including toxic levels of belladonna. The safest options remain the simplest: clean fingers, firm rubber rings, and a cold washcloth to gnaw on.