Most babies get their first tooth around six months of age, though the process can start as early as four months or as late as a year. The full set of twenty primary teeth typically takes about 22 months to come in once the first one appears, wrapping up somewhere between the second and third birthday. While the timeline is fairly predictable at a population level, individual variation is wide, and the experience of teething, from the order teeth appear to the symptoms your baby shows, is more nuanced than the simple chart on your pediatrician’s wall might suggest.
The Typical Eruption Sequence
The lower central incisors, the two front teeth on the bottom, almost always arrive first. They’re followed by the upper central incisors, then the upper lateral incisors (the teeth flanking the front two on top), and then the lower lateral incisors. After the eight front teeth are in, the first molars appear, the upper ones typically slightly ahead of the lower. Canines come next, and the second molars bring up the rear. A cross-sectional study of children’s eruption chronology found that this sequence held for both boys and girls, though the precise timing of each tooth showed differences between sexes.1PubMed Central. Eruption Chronology in Children: A Cross-sectional Study
A useful rule of thumb: corresponding teeth on the left and right sides tend to emerge close together. Research on Australian children found that at least 35% of antimeric pairs (the same tooth on opposite sides of the jaw) appeared within two weeks of each other.2PubMed. Primary tooth emergence in Australian children: timing, sequence and patterns of asymmetry If the left lower central incisor popped through three weeks ago and the right one hasn’t budged, that’s still within normal range. But if one side consistently runs months behind the other across multiple tooth types, it may warrant a conversation with your pediatric dentist.
What Teething Actually Feels Like for Your Baby
Teething has a reputation for causing just about every infant ailment under the sun. The evidence tells a more restrained story. A meta-analysis pooling data from children up to 36 months found that about 70% of infants showed some signs or symptoms during eruption. The most common were gum irritation (reported in roughly 87% of symptomatic children), irritability (about 68%), and drooling (around 56%).3Pediatrics. Signs and Symptoms of Primary Tooth Eruption: A Meta-analysis
A prospective study that tracked individual tooth eruptions more closely confirmed that increased biting, gum-rubbing, sucking, irritability, wakefulness, ear-rubbing, facial rash, decreased appetite for solid foods, and a mild temperature rise were all statistically linked to teeth coming in. What was not linked: congestion, significant sleep disturbance, loose stools, cough, rashes elsewhere on the body, vomiting, or fever above 102°F.4Pediatrics. Symptoms Associated With Infant Teething: A Prospective Study
The fever question deserves its own mention because it comes up so often. A systematic review and meta-analysis found no overall association between fever and primary tooth eruption. When studies that measured rectal temperature specifically were analyzed separately, there was a link, but the temperatures involved were mild elevations, not true fevers.5PubMed Central. Association between Fever and Primary Tooth Eruption: A Systematic Review and Meta-analysis The takeaway: if your baby has a real fever, something else is going on, and blaming it on teething can delay care for an actual infection.
Soothing a Teething Baby
The options fall into two categories: things you put in the baby’s mouth and medications. On the non-drug side, a clinical trial comparing several approaches found that teething rings produced the most favorable results in terms of recovery time and parental satisfaction, followed by comforting and holding the baby, and then rubbing the gums directly.6PubMed Central. Signs and symptoms associated with primary tooth eruption: a clinical trial of nonpharmacological remedies A systematic review confirmed that teething rings were especially effective for drooling, disrupted sleep, gum irritation, and crying.7Braz. oral. res. Efficacy of treatments used to relieve signs and symptoms associated with teething: a systematic review Chilling the ring in the refrigerator (not the freezer, which can make it hard enough to bruise gums) adds a mild numbing effect.
When discomfort is significant, infant-appropriate doses of acetaminophen or ibuprofen (for babies over six months) are the standard pharmacological options. A meta-analysis of pediatric pain trials found the two drugs have comparable efficacy and similar safety profiles at recommended doses.8PubMed. Efficacy and safety of acetaminophen vs ibuprofen for treating children’s pain or fever: a meta-analysis Your pediatrician can confirm the right dose for your child’s weight.
Products to Avoid
Not everything marketed for teething is safe. The FDA issued a warning after laboratory analysis found inconsistent and sometimes dangerously high levels of belladonna, a toxic substance, in certain homeopathic teething tablets. The agency urged consumers not to use these products at all.9The Brown University Child & Adolescent Psychopharmacology Update. Belladonna found in certain homeopathic teething tablets Topical benzocaine gels, once a drugstore staple, also carry FDA warnings for infants because of the risk of methemoglobinemia, a condition where the blood’s oxygen-carrying capacity drops suddenly. The safest approach is to stick with teething rings and, when needed, the over-the-counter pain relievers discussed above.
Folk remedies persist in many cultures. A survey of Indian parents documented the use of various items tied around teething infants’ necks, including copper-containing coins and bead necklaces, as well as over-the-counter homeopathic preparations containing chamomilla.10PubMed Central. Exploring Parental Knowledge and Indigenous Practices for Infant Teething in Indian Population: A Cross-sectional Study Necklaces of any kind, including the popular amber teething necklaces, pose a strangulation and choking hazard and have no demonstrated mechanism for relieving teething pain.
Why Some Babies Get Teeth Early or Late
The textbook “first tooth at six months” is an average, not a rule. Several factors can shift the timeline meaningfully.
Premature birth is one of the most common causes of apparently delayed eruption. A prospective study following 167 infants born between 27 and 40 weeks’ gestational age found that when you counted from the date of birth, premature infants got their first tooth later than term babies. But when you counted from the original due date instead, the difference vanished.11American Journal of Diseases of Children. Teething Age in Prematurely Born Infants More recent work confirmed the same pattern, finding a mean eruption delay of about 2.7 months by calendar age in preterm infants that shrank to roughly 1.4 months when corrected age was used, with preterm babies actually showing a tendency toward faster eruption rates, suggesting catch-up growth.12PubMed Central. Timing of primary maxillary tooth eruption in preterm compared to term infants: a retrospective longitudinal cohort study An additional study found the same correction effect in very low birth weight infants, reinforcing that the delay is a consequence of being born early, not a problem with dental development itself.13Journal of Applied Oral Science. The influence of gestational age and birth weight of the newborn on tooth eruption
Thyroid function also plays a role. Children with hypothyroidism tend to have delayed tooth eruption along with enamel defects, while children with hyperthyroidism can experience accelerated eruption.14PubMed. Thyroid Function during Early Life and Dental Development These effects are part of a broader pattern: thyroid hormones regulate skeletal growth generally, and tooth development follows suit.
In rare cases, teeth fail to erupt at all, a condition called primary failure of eruption (PFE). Non-syndromic PFE is primarily genetic, with an autosomal dominant inheritance pattern, meaning a parent who had the same issue may pass it on. Syndromic forms are associated with broader developmental conditions such as ectodermal dysplasia and cleidocranial dysplasia, where dental eruption failure is one feature among many.15PubMed Central. Syndromic and Non-Syndromic Primary Failure of Tooth Eruption: A Genetic Overview If your child has no teeth by 18 months with no apparent cause, a dental evaluation is reasonable.
Babies Born With Teeth
Every so often, a baby arrives with one or two teeth already visible. These are called natal teeth (present at birth) or neonatal teeth (erupting within the first 30 days). Natal teeth are more common, outnumbering neonatal teeth at a ratio of about 3 to 1.16PubMed Central. Natal and neonatal teeth: an overview of the literature The overall incidence is roughly 1 in 2,000 to 1 in 3,000 live births. The lower front teeth are almost always the ones involved, they usually appear in pairs, and the vast majority are simply early-arriving normal primary teeth rather than extra (supernumerary) ones. Fewer than 10% are supernumerary.17PubMed Central. Natal teeth: a review
The teeth often look different from what you’d expect: smaller, yellowish, cone-shaped, with thin enamel and poor or absent root formation. Potential complications include discomfort during breastfeeding (for both baby and mother), ulceration on the underside of the baby’s tongue, and a very small aspiration risk if a tooth is loose. A dental X-ray helps determine whether the tooth is a genuine primary tooth or a supernumerary one. If it’s supernumerary or dangerously mobile, extraction is recommended. If it’s a real primary tooth that isn’t causing problems, leaving it in place is the preferred approach, since removing it means that spot in the arch will be empty for years until the permanent tooth grows in.17PubMed Central. Natal teeth: a review A pilot study in a large Indian hospital found four natal teeth among 4,341 newborns, with a slight female preponderance and no relationship to the type of delivery.18PubMed Central. Incidence of Natal Teeth in Newborns in Government Medical College and Hospital, Chengalpattu: A Pilot Study
Why Primary Teeth Matter More Than Parents Think
Because they fall out, baby teeth sometimes get dismissed as disposable. They are not. Primary teeth hold space in the jaw for the permanent teeth developing underneath. When a primary tooth is lost prematurely, whether to decay, injury, or extraction, the neighboring teeth can drift into the gap. This reduces the available space for the permanent tooth, setting the stage for crowding, impaction, and the kind of complex orthodontic treatment that space maintenance could have prevented.19PubMed. Space maintenance Restoring a decayed primary tooth, rather than just pulling it, lets it serve as a natural space maintainer until the permanent tooth is ready to take over.
This is one of the reasons dental organizations recommend that children see a dentist by their first birthday or within six months of the first tooth appearing, whichever comes first. In reality, children often make their first dental visit far later. A study evaluating the gap between recommendation and practice noted that many children don’t see a dentist until around age 7, well past the window when early caries and eruption problems can be caught and addressed simply.20PubMed Central. First Dental Visit: Age Reasons Oral Health Status and Dental Treatment Needs among Children Aged 1 Month to 14 Years
How Eruption Reshapes the Mouth’s Microbial Landscape
Before any teeth arrive, your baby’s mouth is a relatively simple microbial environment. Teeth change that dramatically. The hard surfaces of enamel provide a new habitat that soft tissue alone can’t offer, allowing bacteria to form biofilms (plaque) in ways they simply can’t on gums or cheeks. A longitudinal study tracking infants from pre-dentition through the eruption of their first eight teeth found that microbial diversity in both saliva and dental plaque shifted considerably during that front-teeth phase. Interestingly, diversity did not change as much during the later eruption of primary molars, suggesting that the initial introduction of hard surfaces into the mouth is the real turning point for the oral microbiome.21PubMed Central. Maturation of the oral microbiota during primary teeth eruption: a longitudinal, preliminary study
This is relevant for cavity prevention. The bacteria most associated with tooth decay, particularly Streptococcus mutans, colonize teeth, not gums. The window during which a child first acquires these organisms often overlaps with early tooth eruption. Minimizing sugar exposure and avoiding the transfer of saliva from an adult with active decay (through shared utensils, for instance) during this colonization window is one of the more practical things parents can do to reduce their child’s cavity risk.
Teeth and Feeding Independence
The timing of primary tooth eruption isn’t random. It’s tightly linked to when infants start needing solid food. The front incisors arrive right around the age when breast milk alone is no longer sufficient and supplemental feeding begins. Research has shown that deciduous incisors have a prenatal “fast track,” where a greater proportion of the enamel crown forms before birth compared to any other tooth type. This head start allows them to erupt early enough to be functional when mixed feeding begins.22PubMed. Dental fast track: prenatal enamel growth, incisor eruption, and weaning in human infants
Across primates, the timing of molar eruption correlates with major life history milestones such as weaning completion, age at maturity, and lifespan. Modern humans have a distinctly slow dental schedule compared to our closest relatives. In wild chimpanzees, the first permanent molar emerges by about 3.3 years of age.23PubMed Central. First molar eruption, weaning, and life history in living wild chimpanzees In modern humans, the same tooth doesn’t arrive until roughly age 6.24Scientific Reports. Diversity in tooth eruption and life history in humans: illustration from a Pygmy population This nearly doubled delay reflects the broader human strategy of extended childhood dependency, prolonged brain development, and delayed reproduction. Our teeth, in effect, are on the same slow schedule as the rest of our unusually drawn-out growth.
Asymmetric Eruption and What It Can Signal
Parents occasionally notice that teeth on one side of the mouth seem to run ahead of the other. Mild asymmetry is normal and common. But pronounced, persistent asymmetry can sometimes be an early marker of a broader developmental pattern. A study of children with hypodontia (congenitally missing teeth) found that asymmetric tooth formation was elevated across all tooth types in the affected children, not just at the sites where teeth were missing. Asymmetric development occurred in about 19% of cases with hypodontia compared to 12% in controls.25PubMed. Bilateral asymmetry of tooth formation is elevated in children with simple hypodontia The researchers interpreted this as a sign of generalized developmental instability, where the genetic disruption that causes a missing tooth also subtly destabilizes the timing of other teeth throughout the mouth.
Separate research has explored whether functional lateralities, essentially whether a child is right-handed, left-handed, or mixed, relate to eruption symmetry. Children who were not consistently right-sided across hand, foot, and eye dominance showed slightly more symmetric eruption of certain tooth pairs compared to strongly right-sided children.26Archives of Oral Biology. Tooth eruption symmetry in functional lateralities The clinical significance of this finding is modest, but it underscores that tooth eruption is wired into the same deep developmental programs that govern other aspects of bilateral body organization. A tooth popping through your baby’s gum is not just a local event in the jaw. It’s a small readout of the whole organism’s developmental timing.