Children have a total of 20 small white baby teeth in their mouths. From the age of six, each lost baby tooth grows another permanent tooth from below until the age of twelve when they are all replaced with 20 corresponding permanent teeth. But, did you know? At the age of six, when the tooth replacement begins, immediately behind the last milk molar quietly grows a permanent tooth larger than the milk molar is the first permanent molar, the oral cavity up, down, left and right each grows one, a total of four first permanent molar. Because the first permanent molar is about six years old eruption is also known as “six-year-old teeth”. 1. The importance of the sixth age teeth The sixth age teeth are the permanent molars that erupt the earliest, are not replaced for life, and accompany the longest time of life. The crown of the sixth-age tooth is the largest, the occlusal surface is wide, the cusps are high and numerous, and the roots are bifurcated, thick and firmly embedded in the alveolar bone, which bear the greatest chewing force in a person’s life and play a major role in the process of biting and grinding solid food. Especially during the replacement of milk molars, they are the main teeth that bear the chewing function. Sixth-aged teeth are located at the end of the milk teeth and in the middle of the entire dental arch, just like the four pillars of a house, supporting the entire dental arch and playing an important role in the establishment of the occlusal relationship of permanent teeth and the development of the entire jaw bone. The presence of the sixth tooth not only regulates the alignment of the permanent teeth in front of it, but also induces the eruption of the second permanent molar behind it. The occlusal relationship between the maxillary and mandibular sixth-aged teeth determines the occlusal relationship of the entire permanent dental row, so it is also called the “lock and key”. 2.Why are the sixth age teeth most prone to caries? The sixth age teeth are the permanent teeth most prone to caries. There are many grooves and gaps on the surface of the sixth-aged teeth, which are uneven and easy to collect food residues and various bacteria, and it is difficult to clean thoroughly. Because the enamel mineralization on the surface of the newly erupted teeth is not mature, some of the teeth are often accompanied by incomplete enamel development or poor calcification, and there is plaque on the surface of the teeth, which is not acid-resistant and wear-resistant and easy to be carious. When six-year-old teeth just erupted, the far middle is covered by gum, and the gum can only be completely receded after a long time, so this part is especially easy to accumulate plaque and retain food residue, which provides favorable conditions for the occurrence of dental caries. Children seldom pay attention to oral hygiene actively, their ability to brush teeth correctly is poor, and the six-year-old teeth are located at the end of the tooth row, so they cannot be cleaned thoroughly. Over time, the bacteria gathered in the sulcus will use the food residue to ferment and produce acid, which will corrode the sixth age teeth. Because the sixth age teeth are teeth that erupt directly in the oral cavity without replacement, they are often mistaken as milk teeth by parents, resulting in their decay not being treated in time. Some sixth-age teeth have to be extracted due to serious decay, resulting in the disorder of the occlusal relationship of permanent teeth and affecting the facial development. 3.Daily protection of the sixth age teeth The sixth age teeth are the first permanent teeth to erupt, and their position and function are very important, therefore, parents must protect the sixth age teeth. Firstly, all the baby teeth should be examined and treated before the age of six to create a good environment for the eruption of permanent teeth. Secondly, teach children the correct way to brush their teeth, once in the morning and once in the evening. When brushing, focus on brushing the occlusal and buccal surfaces of the sixth-aged teeth. When the six-year-old teeth just erupted, the gum on the far middle side has not completely receded, do not use this tooth to ask for hard food, so as not to bite the gum, do not use your hand to pick, at this time should be carefully cleaned around the teeth plaque, so as to avoid gum inflammation. After the age of six, children can brush their teeth with fluoride toothpaste, and if possible, floss the adjacent space 2-3 times a week. Do not eat before bedtime or after brushing. In addition, teach your child to develop the habit of rinsing after meals. Encourage your child to eat more coarse fiber foods and fresh fruits, drink more plain water, less drinks, and no snacks. Teach children to eat less sweet and soft fine foods, strengthen the exercise of chewing function, and promote the development of upper and lower jaws and face. Maintain good oral hygiene, regular oral examination is very necessary. Every six months, take your child for oral examination, some caries can only be found with the help of oral apparatus, timely filling and early treatment can help the health of teeth. Since the position of the sixth tooth is very important, it must be well protected so that it can give full play to its function. When the sixth age teeth are erupted and caries has not yet occurred, preventive measures can be taken in the hospital, and the common method is sulcus closure. The World Health Organization (WHO) recommends a method to protect the newborn permanent teeth to children all over the world, and our dental prevention organization also recommends this new method to kindergartens, primary and secondary school students all over the country. The theme of our 2010 “Love Teeth Day” is “Closure of Vultures, Protection of Teeth”. Vulval closure is a method to effectively prevent the occurrence of dental caries by applying a layer of adhesive resin material to the occlusal, buccal or lingual surfaces of the dentition without removing the dental tissues to protect the enamel from the erosion of bacteria and metabolic products. The surface of six-year-old teeth has a lot of pits and grooves, these areas are very narrow and easy for bacteria to collect and colonize, and because of the narrow and deep, it is impossible to remove the plaque by professional methods, so the pits and grooves are the good place for caries to occur. According to the statistics of literature, the occurrence of sulcus caries accounts for 86% of dental caries. The material of the sulcus closure closes the narrow and deep sulcus to flatten the tooth surface of the sixth age teeth, which is good for brushing and cleaning and prevents the accumulation and breeding of bacteria. The teeth that have been sealed are like wearing a protective coat, which protects the teeth from bacteria and food residues and reduces the occurrence of dental caries. How easy is it to perform a fissure sealant? There are six steps and it only takes about 10 minutes: 1.Cleaning. Remove the debris and plaque from the tooth surface. 2.Acid etching. To re-clean and facilitate the adhesion of sealant. 3. Rinse and dry. Rinse the weak acid left on the tooth surface and blow dry the tooth surface in a chalky state. 4.Application of sealant. Apply the sealant at the sulcus. 5.Curing. Visible light is irradiated and the sealant hardens in half a minute. 6.Check. Check the sealing effect. Vulgar closure does not destroy the teeth, there is no discomfort, and the filling does not affect chewing and taste. When should I do the fissure closure? Sixth-aged teeth usually do the sulcus closure during 6-8 years old, the crown of the sixth-aged teeth should be completely exposed, if there is gum cover, it can’t be separated from the wet, and the sealant will be easy to fall off. If the caries of milk teeth of children is more serious, it is more important to have the sulcus closure of sixth age teeth in time to prevent the occurrence of permanent tooth caries. Parents should bring their children to the pediatric dentistry department of the designated hospital to do the sulcus closure, and don’t let the children eat too much before the treatment to avoid nausea and vomiting. Parents should tell their children to avoid biting hard and sticky food, such as chewing gum and bubble gum, when the teeth are just closed. Even if it falls out, the sealant has already penetrated into the tooth tissue, just like the roots of a tree rooted in the soil, and still has the effect of sealing. The sealant can remain on the tooth for a long time, but as the permanent teeth erupt, the sealant may wear away and fall out. It is recommended to take your child to the dentist every six months for a routine checkup and to have the sealant re-sealed if there is a large area of loss. It is important to note that the use of gully sealant can prevent the occurrence of gully caries, but it has no preventive effect on the smooth surface of teeth and adjacent surfaces. Fluoride is a chemical caries prevention method, which can effectively prevent the occurrence of caries on the smooth surface of teeth and adjacent surfaces by enhancing the caries resistance of teeth and promoting remineralization. Therefore, the combined use of sulcus sealant and fluoride can prevent both sulcus caries and smooth surface caries, and prevent the occurrence of caries to the maximum. It is not the case that the closed teeth will be free from caries, parents still need to urge their children to brush their teeth carefully.