How Many Teeth Do Humans Have?

Our teeth start to erupt at around 6 months old, and it takes about 2-3 years for all teeth to grow in, during which time we also go through the process of tooth replacement. Some people may find that the number of teeth is not the same for everyone, as some people may have one or two canine teeth, and some people may have wisdom teeth, thus making the number of teeth for each person seem different. So, how many teeth do humans have? Let's take a look below.

During the primary teeth period, there are approximately twenty teeth in a person's mouth, including four central incisors, four lateral incisors, four canine teeth, and eight molars. After the age of six, when the primary teeth are replaced by permanent teeth, the number of teeth in the mouth increases to twenty-eight to thirty-two, which include four central incisors, four lateral incisors, four canine teeth, eight premolars, and eight to twelve molars. These teeth, which have similar names to the primary teeth, are also distributed symmetrically and evenly on both sides of the upper and lower jaws. Compared to primary teeth, permanent teeth have eight additional premolars and four additional molars. Everyone has these eight premolars, but the number of these four molars can vary from person to person, which is why some people only have twenty-eight teeth while others have thirty-two teeth.

Why do some people have 1-4 molars while others do not? This is because during the process of human evolution, due to changes in the living environment and dietary structure, the jaws have become much smaller, leading to the complete or partial degeneration of the third molars (commonly known as wisdom teeth). Therefore, the number of permanent teeth ranges from twenty-eight to thirty-two. It is normal for adults to have twenty-eight to thirty-two teeth, and anything outside of this range is considered abnormal. These abnormal conditions are often caused by abnormal development of the tooth germ, with more than thirty-two teeth being called "supernumerary teeth" and fewer than twenty-eight teeth being called "hypodontia".

Overall, humans have a total of 48-52 teeth in their lifetime, with twenty primary teeth accompanying them through childhood and the permanent teeth replacing them staying with them for life. It is important to protect them, as there are no replacements for permanent teeth if they fall out.

6-8 months: Two central incisors grow in the lower jaw, followed by two incisors growing in the upper jaw.

8-12 months: Two outer incisors grow in the upper jaw, and then two lateral incisors emerge in the lower jaw.

12-16 months: The first primary molars appear in both the upper and lower jaws.

16-20 months: Canine teeth grow in both the upper and lower jaws.

20-30 months: The second primary molars grow in both the upper and lower jaws, completing the growth of all twenty primary teeth. Babies start to get teeth at around 6 months old, and by the time they are around 2 and a half years old, all twenty primary teeth have usually grown in.