Tooth development is the complex process. The teeth form from embryonic cells, grow, and erupt into the mouth. The tooth development is by an large the same for both humans and non-humans. For human teeth to have a healthy oral environment, enamel, dentin, cementum, and the periodontium must all develop during appropriate stages of fetal development. Primary (baby) teeth start to form between the sixth and eighth weeks of pregnancy (in utero), and permanent teeth begin to form in the twentieth week of pregnancy (in utero). If teeth do not start to develop at or near these times, they will not develop at all.

What initiates the development of teeth?

A significant amount of research has focused on determining the processes that initiate tooth development. It is widely accepted that there is a factor within the tissues of the developing foetus that is necessary for the development of teeth.

Nutrition and tooth development

As in other aspects of human growth and development, nutrition has an effect on the developing tooth. Essential nutrients for a healthy tooth include calcium, phosphorus, fluoride, and vitamins A, C, and D. Calcium and phosphorus are needed to properly form the hard part of the tooth (hydroxyapatite crystals), and their levels in the blood are maintained by Vitamin D. Vitamin A is necessary for the formation of keratin, as Vitamin C is for collagen. Fluoride is incorporated into the hydroxyapatite crystal of a developing tooth and makes it more resistant to demineralization and subsequent decay.

Deficiencies of these nutrients can have a wide range of effects on tooth development. In situations where calcium, phosphorus, and vitamin D are deficient, the hard structures of a tooth may be less mineralized. A lack of vitamin A can cause a reduction in the amount of enamel formation. Fluoride deficency causes increased demineralization when the tooth is exposed to an acidic environment, and also delays remineralization. Furthermore, an excess of fluoride while a tooth is in development can lead to a condition known as fluorosis.

Which is the first baby tooth to come in?

Watching your little bundle of joy attain his milestones is the most treasured moment for a parent. Teething is one such milestone. As a parent you can have many doubts and concerns about your baby’s teeth. Baby teeth or milk teeth start coming into the mouth from around 4-6 months. The lower front teeth ( incisors ) are the first ones to come in. Then the upper front teeth erupt ( upto 11-12 months). Your baby will have the molars ( Chewing teeth by 18 months and 36 months) and then the canines ( 24 months ) come in by the 3 rd year.

Human tooth development timeline

The following tables present the development timeline of human teeth. Times for the initial calcification of baby teeth are for weeks of pregnancy (in utero). Abbreviations: wk = weeks; mo = months; yr = years.

Maxillary (upper) teeth
Primary teeth Central
Canine First
Initial calcification 14 wk 16 wk 17 wk 15.5 wk 19 wk
Crown completed 1.5 mo 2.5 mo 9 mo 6 mo 11 mo
Root completed 1.5 yr 2 yr 3.25 yr 2.5 yr 3 yr
 Mandibular (lower) teeth
Initial calcification 14 wk 16 wk 17 wk 15.5 wk 18 wk
Crown completed 2.5 mo 3 mo 9 mo 5.5 mo 10 mo
Root completed 1.5 yr 1.5 yr 3.25 yr 2.5 yr 3 yr


In total, 20 teeth form and erupt in the child. These teeth have to remain in place till their counterparts from the adult teeth come into place. The milk teeth serve the following functions

  • Aesthetics
  • Speech
  • Chewing
  • Maintaining a patent airway
  • Space maintenance for the permanent teeth

All of the above mentioned are important for the child’s overall growth and development. It is important to teach the child early on about the importance of oral hygiene and train your child in good dental hygiene methods like brushing.