It seems there might be a slight misunderstanding in the term used. Based on the provided reference, the concept described relates to the dental formula, not a "dentine formula." Dentine is a substance within the tooth, whereas the dental formula is a way to represent the number and type of teeth.
Therefore, rephrasing the question to accurately reflect the information provided and the standard biological term:
The dental formula is a concise way to represent the number and type of teeth present in a mammal, typically written for one side of the jaw (both upper and lower). It provides a snapshot of the dentition layout.
How is the Dental Formula Formulated?
As stated in the reference from Vedantu, the dental formula is structured as a fraction:
(Number of teeth in half of the upper jaw for each type) / (Number of teeth in half of the lower jaw for the same type of teeth)
The teeth types are listed in a specific order, usually from the front of the mouth to the back:
- Incisors (I): Front teeth for cutting.
- Canines (C): Pointed teeth next to incisors for tearing.
- Premolars (P): Located behind canines, for grinding and crushing.
- Molars (M): Rear teeth for heavy grinding.
The formula is written using the initial letter of each tooth type followed by the count for that type on one side of the upper and lower jaw.
Calculating Total Number of Teeth
To find the total number of teeth in the mouth, the dental formula for one side is multiplied by two, as the formula represents only half of the jaw (one side of the upper and one side of the lower).
Total Teeth = 2 x (I + C + P + M) / (I + C + P + M)
Where the top row represents the counts for the upper jaw side and the bottom row for the lower jaw side.
Human Dental Formulas
Humans have different dental formulas for deciduous (baby) teeth and permanent (adult) teeth.
Adult Human Dental Formula
Adult humans typically have 32 permanent teeth. The formula for one side of the jaw is:
- Incisors: 2 upper, 2 lower
- Canines: 1 upper, 1 lower
- Premolars: 2 upper, 2 lower
- Molars: 3 upper, 3 lower
This is represented as:
I 2/2, C 1/1, P 2/2, M 3/3
To calculate the total number of teeth: 2 (2+1+2+3) = 2 8 = 16 (upper) + 16 (lower) = 32 total teeth.
Child Human Dental Formula
Children typically have 20 deciduous teeth. The formula for one side of the jaw is:
- Incisors: 2 upper, 2 lower
- Canines: 1 upper, 1 lower
- Premolars: 0 upper, 0 lower (Baby teeth don't have premolars)
- Molars: 2 upper, 2 lower
This is represented as:
I 2/2, C 1/1, P 0/0, M 2/2
To calculate the total number of teeth: 2 (2+1+0+2) = 2 5 = 10 (upper) + 10 (lower) = 20 total teeth.
Summary Table
Here's a quick look at the human dental formulas:
| Tooth Type | Adult (Permanent) Upper/Lower (per side) | Child (Deciduous) Upper/Lower (per side) |
|---|---|---|
| Incisors | 2/2 | 2/2 |
| Canines | 1/1 | 1/1 |
| Premolars | 2/2 | 0/0 |
| Molars | 3/3 | 2/2 |
| Total | 8/8 per side (16 upper + 16 lower = 32 total) | 5/5 per side (10 upper + 10 lower = 20 total) |
Understanding the dental formula helps in comparing dentition across different species and stages of life.
