Tooth Replacement in Children: Sequence and Approximate Timing

Primary teeth are the first set, and sooner or later they give way to the permanent set. It is useful for parents to understand the general sequence and approximate timing so they know what is happening in their child's mouth. Below are reference points that describe the process on average.

When tooth replacement begins in children

The first primary tooth usually erupts at about 6 months, although it may happen earlier or later. There are 20 primary teeth in total: 10 in the upper jaw and 10 in the lower jaw, 5 on each side of the jaw — two incisors, a canine, and two molars. Teeth of the same name on each side of the jaw appear at the same time, and lower teeth usually appear before upper ones.

The primary dentition is divided into two periods. The first lasts from formation to 3.5 years: the teeth are closely spaced, without gaps, and wear is not noticeable. The second period is from 3.5 to 6 years: the jaws grow, physiological spaces appear between the teeth (diastemas and tremas), the bite changes from orthognathic to straight, and signs of noticeable wear appear. The replacement itself is the mixed dentition period, when primary teeth are still present and permanent teeth are already erupting.

Approximate timing of tooth replacement

There are no calendar dates for the loss of each individual tooth in the reference base, so the reference points describe the process on average rather than a schedule.

• 6–7 years — permanent posterior teeth begin to erupt;
• 11 years — second molars;
• 12–13 years — the permanent bite is formed;
• 3–4 months — the usual interval between the loss of a primary tooth and the eruption of the permanent one.

Sequence of loss and eruption of permanent teeth

The sequence of replacement roughly corresponds to the order in which the primary teeth erupted: teeth of the same name on the right and left change almost synchronously, and lower teeth are ahead of upper ones. In girls, eruption occurs somewhat earlier than in boys.

The mixed dentition ends with the formation of the permanent bite. If a primary tooth has fallen out and something remains in the gum that worries parents, the situation is assessed by a dentist during an examination.

Until what age teeth change

By 12–13 years, the permanent bite is formed. The longest wait is for wisdom teeth — they erupt at 17–25 years or later, and may not appear at all. The eruption of individual permanent teeth therefore stretches over years.

When tooth replacement does not follow the schedule

Variation is inherent in the process itself: the timing of eruption and replacement is individual, so the same picture in two children of the same age may look different.

A situation that deserves separate discussion is when primary teeth have not fallen out and new ones are already growing. The cause of the delay is determined by the dentist after an examination. The decision on whether interventions are needed and when is made by the doctor and parents together.

When to show the child to a dentist

The first visit to the dentist is planned for when the first primary teeth appear, or before 12 months: this way the child gets used to the setting, and the doctor assesses the condition of the oral cavity. After that — regular examinations at the times set by the dentist. Questions about tooth replacement are also a reason to come outside the schedule: a primary tooth does not fall out for a long time, a permanent tooth does not appear for a long time in the place of the one that fell out, something remains in the gum after a tooth falls out.

During the examination, the dentist assesses the condition of the oral cavity and gives recommendations for further examinations. The preventive part includes fluoride varnish, which is offered from 3 years of age at least twice a year, and sealing of the fissures of permanent posterior teeth, which is done after their eruption, usually around 6–7 years, and again between 11 and 14 years.

Tooth replacement itself is not a reason to call an ambulance. 103 or 112 — if the child has a serious injury to the face or jaw or another life-threatening condition.

The material is for reference and does not replace a doctor's consultation: only a dentist during an appointment can assess a specific situation.

This content is for reference and does not replace a doctor's consultation. Medical disclaimer