Health and safety

Understanding about the development of dentition

Timings of milk teeth development

Development of dentition

Dentition means a set of teeth. The purpose of this article is to discuss the main course of normal development of human dentition, its influence by the prenatal and postnatal environment and getting to know the most common developmental disturbance and how to avoid and manage such occurrence.

The milk teeth

Why it is so called, have you ever wondered? The milk teeth are called as the milk teeth because the refractive index of the milk teeth is same as that of milk. The Exciting Moment is when the parents see the first teeth appear in the child’s mouth.

The initiation of development of all milk teeth occur between 3.5 to 4.5 intrauterine months and the development process continues. The first tooth that is the lower incisors see the world at 6th month of the child’s life. This process of eruption of milk teeth is known as teething. For it is the most important early milestone in development of a child. The teething process starts at the sixth month and they continue to appear till the child is two and a half years old.

The milk teeth period starts on the arrival of the lower central incisors, usually between the sixth to eight months, and lasts until the first permanent molars appear in the mouth, usually at six years. During milk teeth period, the tooth buds of permanent teeth develop below the primary teeth, close to the palate or tongue.

The teething occurs in the following manner and teeth erupt sooner in females than males.

Timings of milk teeth development

Lower
1. Central Incisors – 6 months
2. Lateral incisors – 7 months
3. Canines – 16 months
3. First molars – 12 months
4. Second molars – 20 months

Upper
1. Central Incisors – 71/2 months
2. Lateral Incisors – 9 months
3. Canines – 18 months
4. First molars – 14 months
5. Second molars – 24 months

Signs of teething
In most cases eruption doesn’t cause any distress, but sometimes it may cause
1. Local irritation
2. Inflammation of overlying gum tissues
3. Baby wants to bite anything he puts in his mouth usually solid stuffs
4. Restlessness sometimes diarrhea
5. Sucks finger

This can be prevented by maintaining child’s oral and general body hygiene. Adequate quantity of vitamins, minerals, proteins are given to the child so that the body’s resistance is increased. Use of teething objects, a variety of objects differing in size and shape and composition have been advocated to satisfy the natural desire of the baby to chew on hard objects during the teething process.

Nutrition and teething

As in other aspects of growth and development, nutrition has an effect on the developing tooth. Essential nutrients for a healthy tooth include calcium, phosphorus, and vitamins A, C, and D.

Calcium and phosphorus are needed to properly form the hydroxyapatite crystals, which is the primary mineral of the tooth enamel. Calcium and phosphors levels in the blood are maintained by Vitamin D. 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 deficiency causes increased demineralization when the tooth is exposed to an acidic environment, and also delays remineralisation. Furthermore, an excess of fluoride while a tooth is in development can lead to a condition known fluorosis.

Developmental disturbance
Dental development disorders may occur as a result of numerous inherited syndromes, improper prenatal development, endocrine disorders, and environmental factors.

Some Developmental disorders include
1. Hypodontia lack of some tooth development.
2. Anodontia, a very rare condition. It is the lack of teeth.
3. Supernumerary or Extra teeth: These are more common in permanent teeth than in baby teeth; extra teeth usually are somewhat shapeless pegs, although occasionally an extra molar develops fully.

Discoloured and misshapen teeth that may cause discoloration of the teeth include
1. Hypoplasia in which insufficient or irregular enamelling of the teeth caused by the administration of tetracycline to a pregnant or nursing mother or to the infant or young child.

2. Enamel and Dentin hypoplasia, in which the enamel and dentin are not calcified (hardened by the depositing of minerals) due to vitamin D deficiency during tooth development.

3. Hypo calcification, in which the enamel is of poor quality due to genetic factors, extensive plaque deposits, excessive sucking on citrus fruits, or high consumption of very acidic carbonated beverages.

4. Amelogenesis imperfecta, an inherited defect that causes thin and discoloured enamel.

5. Dentinogenesis Imperfecta, a defect of the dentin that causes discoloration and loss of enamel.

6. Extrinsic enamel coloration due to liquid iron supplements administered for anaemia or due to plaque or stains adhering to calculus, hard mineral deposits on the crowns and roots.

7. Intrinsic enamel coloration due to pigments carried in the blood from tetracycline or other drugs or from excessive fluoride Illness or trauma during infancy or early childhood, including infections, high fever, malnutrition, or disorders such as congenital syphilis or Down syndrome, can cause misshapen or discoloured teeth. Both the baby teeth and the permanent teeth are usually affected, particularly the eight front teeth and the six-year or first molars. Crowns may be pitted, grooved, and discoloured.

8. Dental Fluorosis: Critical period is age 2-3, if fluoride levels greater than 1 part per million are ingested it leads to this condition. Fluoride comes from several sources besides water. Adult-strength fluoride toothpastes, fluoride supplements, infant foods, soft drinks, and fruit juices. Severity is dose dependent. Higher intakes during critical periods associated with more severe fluorosis. Teeth affected by fluorosis may appear mildly discoloured from lacy white in mild to yellow or brown colour in severe cases.

Read Overall Dental Health of a Child

About the author

Dr. Shreen Fatima

The writer is a practising dentist who has a passion for kids dental health and who herself enjoys dealing with kids. Being herself a mother of a kid wants to share her knowledge on dental health care for the benefit of the child's well-being.