[Music] we concluded the previous video with a new term it's called the human dentition any idea what it could mean something related to teeth I know but what exactly is it let's understand the definition of human dentition first it's defined as the study of the teeth pattern and their functions in humans okay so what we've been studying so far is dentition somewhat yes we have studied a few concepts related to teeth and now we learn a few more technically dentition is the characteristic arrangement kind and number of teeth in a given species at a given age that means in a particular species how the teeth are arranged what are the characteristic features of those teeth like the size shape and so on and also how many teeth in total are present is what the dentition tells us can you tell me how many teeth do V humans have the instant answer we give is 32 but is that really the case with all let's find that out humans like other mammals are diffident and what does that mean deaf ear don't in simple words means having two sets of teeth and does that refer to the teeth on both upper and the lower jaws nope absolutely not humans have two sets of teeth one is the deciduous and the other is the permanent set of teeth now what are these exactly we know that a few months after birth a set of teeth begin to appear in the baby these teeth are called the baby teeth or the milk teeth or the primary or even the deciduous teeth after these teeth fall away the next set of permanent teeth begin to appear so the primary and then the permanent are the two sets of teeth in the life of humans due to which we are called diffident and what's the number of these teeth well the teeth are usually training number and the growth of the entire set of these teeth is generally completed by the time a child is 2 or 3 years old the next set of permanent teeth that starts developing is at around 5 years of age the training milk teeth are later replaced by around 30 to permanent teeth yes the 32 teeth that we usually talk about now can you tell me the number of each type of teeth is it fixed or random it's definitely fixed and how is that determined you will be surprised to know that there are formulae to understand the dentition pattern in different animals including humans yes they are called the dental formulae the number and the arrangement of the teeth in the human's form the human dental formula for an adult human mouth the dental formula is given as 2 1 2 3 by 2 1 2 3 and how is that read take this representation for example here let's focus on the upper jaw first here if we divide the complete jaw in equal halves we get two incisors one canine two premolars and three molars so this makes up 8 teeth on one side of the upper jaw same is the case with the other half yes 2 1 2 3 so 8 and 8 give us 16 teeth in the upper jaw now what about the lower jaw if we carefully count then the lower jaw also has two incisors one canine two premolars and three molars so here is well we get sixteen teeth in total and together we get thirty-two teeth on adding the ones from both jaws since we have two incisors one canine two premolars and three molars on both upper and lower jaws on each side we write the formula as two one two three by two one two three now here we have an image of an infant mouth with primary or the milk teeth can you tell me the dental formula for this arrangement okay let me give you a hint there are in total twenty milk teeth in infants now try cracking this interesting question and do leave your answers in the comment section below [Music] you