Vaginal pH and what you need to know
Article by Doctor Nguyen Thanh Xuan about Vaginal pH - the vagina has a very rich resident microflora including beneficial and harmful microorganisms
Permanent premolars (permanent premolars) are placed between the anterior and molars. Eight premolars are found in the permanent dentition. Of these, 4 on each arc and two in each quadrant. The main function of the premolars is to assist the canines in tearing and stabbing food. They complement the grinding of the molars during chewing. Other functions are to support the corners of the mouth, enhance the smile appearance, and maintain verticality.
content
1. Introduction to premolars (RCNs)
Terms
In English, RCN is also known by another common name "bicuspid" (two-pack teeth). However, RCNs are not always bipartite, so this designation is not widely used. The word for RCN in English and French is "premolar, premolaire", which is often translated into Vietnamese as "pre-jam", "pre-mortem". Although this term is still quite common and seems acceptable in translation, it is not biologically appropriate.
Time to grow
As we all know, there are 8 premolars (also known as premolars) on the human permanent teeth. The erupting RCNs replace the primary molars. They erupt between the ages of 9 and 11, before the eruption of the 2nd molars. The upper and lower first (first premolars 1) erupt relatively simultaneously (at about 9 years of age). This was followed by second RCNs (2 premolars) at about 11 years of age.
>> You can see more: The stages and time of teething of children that mothers should know .
4 premolars of the upper jaw
Quantily
Primitive humans had four premolars in each quadrant, or 16 per person. Over time, the central premolars – the teeth closest to the front of the mouth – were lost. Paleontologists refer to these medial premolars as 3rd and 4th premolars.
Body shape, function
The premolars occupy the position between the canines and the molars on the dental arch. Morphologically, they can be seen as a transition between canines and molars. We already know that canines have a wedge-shaped cusp suitable for biting or tearing. While molars have many segments and wide chewing surfaces, suitable for chewing and grinding functions.
RCN has at least one large and sharp cusp (outer cusps of the lower premolar). Or have 2-3 packs and have a relatively small chewing surface compared to molars (molars), suitable for stamping function. The RCNs and molars form a group of posterior teeth.
Summary of features of the premolar group:
2. Upper molars
Premolars 1 upper and lower jaw
Size and age of eruption of upper premolars
Dimensions (mm) |
RCN 1 |
RCN 2 |
Tartar Near and far from the crown Outside in the crown Totally high Near and far from the neck of the tooth Outside in the neck of the tooth Age of growth |
9.3 7.5 9.7 22.5 5.3 8.7 9 |
8.8 7.2 9.5 22.2 5.3 8.8 ten |
3. Lower premolars
The lower RCN 1 from a purely functional point of view can be viewed as a canine. While the lower RCN 2 is like a miniature molar . Therefore, these two teeth do not resemble each other as much as the two RCNs above.
Premolars 2 upper and lower jaws
Features of the lower premolar arch:
Size and age of eruption of lower premolars
Dimensions (mm) |
RCN 1 |
RCN 2 |
Tartar Near and far from the crown Outside in the crown Totally high Near and far from the neck of the tooth Outside in the neck of the tooth Age of growth |
9.5 7.8 8.5 24 5.0 7.3 9 |
9.0 7.8 9.0 24 5.2 7.7 ten |
4. The difference between the upper and lower premolars
There are several common features that distinguish the upper RCN from other posterior teeth and the mandibular RCN:
Premolars are teeth that have a transitional shape between canines and molars. They perform the function to support the process of grinding and tearing food of the molars. Permanent RCNs erupt at the ages of 9-11, to replace the primary molars. When the baby molars are lost early, it will delay the eruption of permanent premolars. Therefore, we need to protect the baby molars until the time of tooth replacement is appropriate, to avoid early loss of caries.
Doctor Truong My Linh
Article by Doctor Nguyen Thanh Xuan about Vaginal pH - the vagina has a very rich resident microflora including beneficial and harmful microorganisms
On the human body, there are about 49 sesame bones of different sizes. Sesamoid bones are small bones located below tendons, commonly found in the joints of the hands and feet.
The seminal vesicles in humans are part of the male reproductive system. This unit has a distinct structure and function. It plays a role in semen production
The article was consulted by doctor Nguyen Huynh Uyen Tam about ureters, ureteral function and some related diseases.
Article by Doctor Nguyen Doan Trong Nhan about testicles. There are many conditions that affect the testicles and can sometimes lead to infertility.
Enamel is the outermost layer, plays a protective role and is also the strongest component. Although hard, enamel can still crack, chip and be dissolved by acids
Gums play an important role in the oral system. It helps to cover, create aesthetics for the mouth area, protect and prevent the penetration of bacteria
The temporal lobe is one of the main lobes that make up the human brain. This lobe of the brain has distinct functions.
Doctor Nguyen Lam Giang's article about the lacrimal gland, a very specific exocrine gland in humans, thanks to the lacrimal gland we can express our emotions
Article by Doctor Luong Sy Bac about tibia. The tibia is the large bone in the lower leg that bears the main force of the body and is often injured.