 Hello everyone, welcome back to a new session on dentistry and more. So today we have a new topic that is flu rights. So flu rights will be covered under a different session. So today's sessions will be covering about history of flu rights. So what is so much special about flu rights in dentistry? Nowadays we see flu rights in almost all the dental products like toothpaste or mouth washes or gels. Everything has to read because it has proven that flu right can prevent dental caries to an extent. And fluoride is the most significant element which prevents dental caries. So how we know that the flu rate can prevent dental caries? It is like almost a centurion acquired by the scientist and epidemiologist which has ultimately reached a conclusion that flu right can prevent dental caries. So we have to study the history of flu rate, how the element was invented, how it was found out that flu right causes fluorosis then it was used to prevent dental caries. And all this will be covered in this chapter. And today's section will be covering about the history of flu rights. The scientist and their inventions, their contribution and the significant contribution by new scientist ultimately that contribution leads to the conclusion that flu right prevent dental caries. So let's see the some basic things about flu rate. It has atomic weight 19 atomic number nine and it is derived from a Latin word fluro. That means to flow and it is very electronegative element. So it cannot exist as an element and it always stays like with the compound. It combines with some other element and like calcium fluoride for sodium fluoride. So it always exists as compounds. So let's see the historical evolution of flu rights. So we have to start with a famous dentist named Frederick McKay. So in 1901 he finished his dental graduation from Pennsylvania dental school and started practicing in a city known as Colorado Springs in USA. So there he found out in many patients some peculiar enamel markings. And he would not find any scientific literature to substantiate this peculiar enamel markings and the discoloration or hypomentalization or the brown discoloration on the teeth. And he called this enamel as motile enamel. So it looked like white flex, yellow or brown spots which are scattered irregularly and streaked our surface of the tooth. So Dr. Frederick McKay was the first name you should remember. He was the pioneer in the fluorosis or the fluorine identification or fluoride and dental caries or fluorine and fluorosis identification. So Dr. Frederick McKay in 1901. So he identified the Colorado Springs or Colorado motile enamel. Then came Dr. GV Black. So he approached another doctor or dentist named GV Black. He was that time Dean of Northwestern University Dental School. So he did not actually believe it. The theory of all the findings of Dr. Frederick McKay. But what he did was he collected some motile enamel samples and agreed to attend the Colorado State Dental Association 1901, 1909 and spend some time in Colorado. So agreed to visit Colorado Springs for further investigation. But meanwhile, what our Frederick McKay did was he did a study with the help of Isaac Burton, a flaming. He did examination among almost 3,000 children in public schools of Colorado Springs and found out that almost 88% of children were with motile enamel. And he published the same findings along with GV Black as an endemic imperfection of enamel of teeth here to for unknown in literature of dentistry. This was the first published finding of dental fluorosis or motile enamel. But still they were not able to find out what was the cause. So in 1916, McKay and GV Black conducted studies on individuals that is from 26 different communities in USA and concluded that a particular factor in the water causing this motling of the enamel. And that was affecting during the tooth calcification. So similar motlings were seen in the city of Britain. So it was sitting in the USA, not in the United Kingdom. So Britain, where the water supply, people drinking water supply was changed from shout out to deep wells in 1898. So it was found that people were born before 1898 were having normal teeth and people who went after 1898. In another word, we can say that people who started drinking the deep well water are started showing enamel motling. So it made them believe that it was due to the particular factor in the water which causing enamel motling. The same thing was also happened in Bauxite. Because in 1909, this water changed from shallow to deep water. Then came another scientist, H. V. Churchill. He was a chief chemist in Alcova company in Pennsylvania. So that time in USA, people were using aluminum for cooking. But they mentioned that aluminum utensils caused poisoning. Because most of the aluminum product that Alcova company taking from Bauxite area was aluminum, just taken from Bauxite. And in Bauxite, there were a lot of dental enamel motling. So they thought this problem with aluminum because in Bauxite region, there are people with motling of enamel. So it could affect us also because of this particular aluminum product. So Alcova company had to answer for this poisoning theory by the people of USA. Because of the Bauxite region people showing enamel motling. And they thought that it was due to the aluminum. And Churchill took sample from Bauxite and did analysis and found out that 13.7 parts per million of fluoride was present in Bauxite waters. So Churchill was the first person who found out the presence of fluorine in water. And later he started collecting samples from various regions. Like Colorado Spring had two PPM and Bauxite, as I mentioned, 13.7. Well-near Kiddur, 12 PPM, then 11 PPM and six PPM. So various regions where this motling were recorded are having high amount of fluorine in the drinking water setup. But still there was no precise correlation between fluoride content and this motling enamel. They could not establish a proper fossil link between this fluoride and motling of the enamel. Thereby, this company proved that it was not due to the aluminum, or aluminum is not a poison. It was due to the amount of fluorine in the water which is causing fluorosis or the motling of the enamel at Bauxite region. So it was to protect their company but accidentally they found out the element fluorine. So next came the famous epitomologist or public health scientist, Dr. H.T. Dean, or H.Trendley Dean. He conducted some landmark survey in the history of evolution of fluorides that is the Shu Leather Survey. It is commonly asked question and it is very interesting. The name is very interesting Shu Leather Survey. So he was appointed by United State Public Health to continue the work of Meche. So they wanted to continue the work of Dr. Meche. What was the reason for this motling of the enamel and what is the connection between fluoride and this motling of the enamel? Because by the time fluoride was already into picture and they wanted to show or prove that this could be a reason for the fluoride could be the reason for fluorosis or motling of the enamel. So Shu Leather Survey was done by Dr. H.T. Dean. So his first task was to continue Meche's work to find the extent and geographic distribution of motling enamel. So he wanted to see how far it is distributed, how much area it was affected. So what he did was he started posting lectures to local and state and society in country, local physicians asking if motling enamel existed in their area. So almost 1200 letters he sent and 632 replies were received. Then he started his famous Shu Leather Survey. Dean and his colleagues started Shu Leather Survey among the 22 cities in 10 states of USA. And collected 5,824 children and gave a report. And why it was known as Shu Leather Survey? Because it was a door to door survey because he started walking to each place or his friends started walking asking questions. So it was involving a lot of walking hence it was called as Shu Leather Survey because of this door to door survey and a lot of walking. And what they found out was a striking feature. You can see that this blank one is normal enamel and this black one is motling enamel. So you can see as the PPM of fluoride is increasing the motling also started increasing. So you can see 0.6 PPM there is no motling, 0.9 there is very little, very mild motling 1.7, 2.5, 2.9, 3.9 and 4.6 the high motling is seen. So they could found out that the presence of fluorine is directly proportional to the motling of the enamel. That was the biggest conclusion of this Shu Leather Survey directly proportional fluorine and motling. Then this gave the report like a high concentration of fluorine water is directly related to the motling enamel motling was widespread in areas with water content more than 3 PPM with a discrete pitting if it is more than 4 PPM. Whereas motling was less where it is 2.503 and no motling was present where it is around 1 PPM. So this were the conclusions of Shu Leather Survey. So motling enamel gave way to more exact terms. So they started calling this motling of enamel as dental fluorosis because the perfection imperfection was caused by fluorine. So they started calling as dental fluorosis. And in 1934 Dean standardized a classification of fluorosis and it is known as Dean's Fluorosis Index. We have already learned it in a practical session and it was modified later in 1942. And in 1942 he found out that drinking 1 PPM of water would reduce a caries by 60 percentage. Then he conducted another study 21 cities study. Okay, this is different from Fluorosis Survey. This was done by Dean Arnold and Elvov in 1942. So what he wanted to prove that there is a inverse relationship between this fluorosis and dental caries because what he observed was wherever this fluorosis is present the dental caries was very less. So he wanted to prove that the fluorine and caries are inverse relationship. Sorry, not the caries and fluorosis and dental caries. So what he did was caries experience was investigated among 7,257 children that is between 12 to 14 years from the 21 cities of four states. Okay, this Shu Leather Survey was different. It was done among the 22 cities of 10 states whereas 21 city studies were done in four states. Okay, so it was done in four states but 21 cities. It was to prove the relationship of dental fluorosis and dental caries but Shu Leather Survey was done to prove that enamel, modeling and the amount of fluorine and water. There is no caries in Shu Leather Survey. So in 21 cities concluded that there is an association between the increasing fluoride concentration in the drinking water and decreasing caries experience. So that was a landmark conclusion which created history in public health because they found out that maximal reduction in caries experience occurred with the concentration of 1 ppm of fluoride drinking water and this became the foundation of agoridation of water, fluoridation of toothpaste, fluoridation of all the other products to get a net effect of 1 ppm. So 1 ppm was approved by the World Health Organization in later times so as to provide fluorides to people with less or more caries area and less fluoride in drinking water. WHO only recommended to start water fluoridation to get the benefit of fluorine to prevent dental caries. So it is like double A sword, if it goes very higher it creates problem like fluorosis. If it is very less it has no benefit and there will be caries. So it has to be at a optimal level that is 1 ppm. So this was the graph where they found out after the 21 cities studies. So we can see that the ppm is on the x-axis and the caries experience on the y-axis, okay. So we can see there is a inverse relationship as the fluoride content is going high there is a significant reduction in the caries. Can see this curve is going downward as the fluoride is going on the x-axis. So there is a inverse relationship between caries experience and fluoride. So that's all about history of fluorides. So in next session we'll be seeing about systemic fluoride where they started water fluoridation studies. After this World Health Organization or the not World Health Organization after this US Public Health Service started giving permission to water fluoridations in certain cities. And it has all proved that there was a reduction of around 50 to 60 seconds. So that was a different story of the water fluoridation studies. And it was among some six, seven cities in Canada and USA. So they all proved that water fluoridation was effective in preventing dental caries. So that's all about history of dental fluorosis and its effect with dental caries. And just for your information, fluorides are present all over the lithosphere, biosphere and atmosphere. So it is an organic fluoride compound. And it is this lake you have to remember highest natural fluoride concentration is Nakuru Lake in Kenya, almost 2,800 ppm. So we were talking about 3, 4, 5 ppm. And this is 2,800 ppm that is Lake Nakuru in Kenya. And 15 states in India are affected with fluorosis. Some states almost 50 to 100 states. These all are coming in fluoride toxicity. So I just want to show that some natural products which is having high amount of fluoride that is tea leaves having high amount of fluoride that is 3.22, 400 ppm. And the fish products like salmons, sargeens, fluoride content, cereals, bananas. So that's all about history of fluorides. It started from Dr. Frederick McKay, then G.V. Black, then Churchill, then came our famous trend, H.D. Conductor 21 city studies and shoo leather survey. Finally found out that giving 1 ppm fluoride in drinking water could prevent entry carries. So U.S. Public Health adopted this concept and started giving permission for water fluoridation. So after that 1945, the first artificial fluoridation started in USA. So in next video I'll be explaining more about this water fluoridation studies under systemic water fluoridation. So this video mainly includes the history of fluorides and various scientists, various surveys and landmark achievements by the scientist. So the next sessions will be having systemic topical fluoride toxicity and de-fluidation techniques. But in India there is no scope for water fluoridation because as I told you, 15 out of 30 states, including the unitary trees are affected with endemic fluorosis. So we are into the action of de-fluidation but this community water fluoridation is a great moment and a great invention in the public health sector. And it was started in USA and they continued this water fluoridation for at least 30 to 40 years and then around 1970 since this two-spaced star into the market which provide equal effect of caries protection, it slowly started disappearing. All most of the plants were closed around 1970s because the same benefit could be obtained by the two-paced, so why to waste so much money? The installation charges were water fluoridation but this was how fluoride came into our dentistry. And how we protected dental caries is one of the landmark invention or achievement by the public health. So I'll come up with a system of fluoridation in my next video. So today's topic is systemic fluoride. So systemic fluoride is about how fluoride is used by a person. We can use it by two methods, one is systemic route and the another one is topical routes. So today's video will cover the systemic fluorides and its methods, its advantages, the mechanism. The next video I'll be covering about the topical fluorides. So in systemic fluorides, as the name suggests, it's a route of administration is systemic and its effect on the teeth is different compared to the topical ones. So let's move on to the topic. So let's see what are the contents, how it is working types and what are fluoridation studies, school and salt, milk fluoridation and the other supplements, shingles, stables, lozenges and other things. So systemic fluorides, it provides a very low concentration of fluoride to the teeth for a longer period of time. Mostly the systemic fluoride works till six or seven years, why? Because it affects the mineralization stages of teeth. So mineralization stages complete by seven years, that is the second molars, the second last tooth of our eruption sequence, second last tooth is second molar. It gets mineralized by the age of six or seven. So the systemic fluoride should use this potential. After that, there's no point for systemic fluoridation because it goes to our bloodstream, it enters to our bloodstream. Sorry. Then this fluoride enters to the teeth while it's getting mineralized and it gives a firm structure to the firm art structure to the enamel. So it becomes resistant to dental caries, that is the rational behind the systemic fluoridation. So it should be before six to seven years. So once the teeth erupts, fluoride contacts the teeth through the salivary secretion, but that is a topical effect. So that is systemic fluorides. So I mentioned you about its mechanism. It goes to the developing stages of teeth until six or seven years and it replaces a hydroxyl ion in the enamel lattice and replaces replaced with fluoride. It makes the enamel lattice more stronger. So that is a mechanism. So we have various types of systemic fluorides. The common one is water fluoridation, then salt, milk and fluoride tablets. In water fluoridation, we have community and school water fluoridation. So it's all we are consuming inside. It enters the systemic circulation. So let's see a brief intro of all these mechanisms. Water fluoridation, commonly we use one PPM, that is one past per million. In salt or school water fluoridation, it ranges from two to three PPM because the amount of water consumed by the school children will be low and the amount of the days the children's attend will be less compared to community water fluoridation because community water fluoride supplies water to the house. So we tend to drink more water from the house than compared to the school. So to get a one PPM effect, we need to have more increase the PPM or concentration of fluoride because of the less intake in salt or school water fluoridation milk. Again, it is comparatively very less consumption than the salt or school water. So it has to be by PPM to get a one PPM net effect. And we have some other supplements like fluoride tablets, APF, sodium fluoride and other stuff. So by definition, it is the upward adjustment of concentration of fluoride. So we are increasing the amount of fluoride to get an optimal level so as to give a maximum protection against dental caries. So it is upward adjustment of the concentration of fluoride in community water supply to achieve a maximum caries reduction and clinically in significant level of fluorosis. So we are giving an upward adjustment. So defluidation will be learning in the future videos. So that will be downward adjustment. So water fluoridation is always upward adjustment. Presently the fluoride amount will be very less. So we increase the amount of fluoride. So water fluoridation is one of the common delivery mechanisms because of its low post and long range. The problem is always we need to control the PPM water and it depends on the regional temperature. If it is a hot climate or hot region, we have to give less PPM and it on a colder climate, we have to increase the PPM. So the optimal, as I mentioned, it should be one PPM or one parts per million. It gives a 50 to 70 percentage of reduction from the dental caries. So we have seen the history of fluoride, our history of fluoride evolved and ultimately reached to the water fluoridation. So we have some water fluoridation studies. So it proves that the water fluoridation mechanism would definitely reduce the caries by 40 to 60 percentage. So the first water fluoridation program was started in United States in 1945. There was Grand Rapids Muskegon study, the Newark Instance, Evanston Oak Park, Grand Flood, Sarnia, Stratford study and Tiel Bloomberg study. So all these studies are very important with respect to the water fluoridation. The first study we need not to go very in detail about all these studies. Just need to know what time it started, what was the percentage reduction and how much duration was it. So it started in 1945 in Grand Rapids. That was the water fluoridation city and Muskegon was kept as controlled. After six years, the caries reduction was 50 percentage compared to the control city. Okay, so that is the first study, Grand Rapids and Muskegon study. So always the first city will be the intervention city and the second name will be the control city. The reduction was 50 percentage. And after six years, started in 1945, checked 1951, okay. So the second study in Newark, Kingston, Newark was the intervention and Kingston was the control. It started in 1945, after 10 years, the reduction was 23.5 to 13.9 percentage. So the next study is Evanston Oak Park, 1946. The intervention was at Evanston and Illinois and the nearby community Oak Park acted as a control town. So it was 14 years of fluoridation and the reduction was 49 percentage. So Evanston was an intervention city, Oak Park Act, Illinois, where the control cities. The Brandford, Sarnia, Brandford study. So Brandford was intervention, was in Canada. So 1945, so Sarnia along with Stratford were kept as a control. So after 17 years of fluoridation, the Brandford, Brandford and Brandford were reported. Brandford and this Stratford controls were reported. 50 percentage of fluoridation and the control. So this was the intervention. These two were the controls of 55 percentage of reduction of case was reported at intervention that is Brandford city. Teal Coulomburg was, steel was, its study was in 1953. Teal was fluoridated, Coulomburg was kept as control and after 13 years, it was 58 percentage reduction in the intervention city. That is steel. So those were the water fluoridation studies. Most of the studies reported around 50 to 60 percentage of reduction of dental cases. So how the temperature affects this fluoride level that is we're going to discuss. We have said the optimal level is not exactly one it ranges from 0.7 to 1.2 because when it is very high temperature or the temperature of this area or the water is more, we have to give very less amount that is 0.7 is fine. And the colder side, we have to give 1.2 ppm. So it is based on a formula that is Kalkan's formula that is 0.34 divided by E. E is minus 0.038 plus 0.062 X temperature of the area. So we have to multiply into temperature. So E is coming at the denominator. So always temperature is inversely proportional to the amount of fluoride. So what are the prerequirements of water fluoridation? So there should be some significant amount of carries in community and level of fluoride concentration should be low. There should be centralized water supply and there should be acceptance from the community and there will be huge installation and maintenance cost. So this is important because these are the three mechanisms or the equipments used for water fluoridation that is dry feeder, solution feeder and saturation method. In dry feeder, the amount, the compound such as ammonium, silica fluoride and flow spar, sodium silica fluoride is used, solution feeder, hydrofluorosilic acid. So three mechanisms, this is a mechanism used for water fluoridation or the equipments fluoride, equipments, dry feeder, solution feeder and saturation feeder. How fluoride is mixed to the water, community water. So then the saturation system, the last system, what we are doing is 4% saturated solution of sodium fluoride. It is injected at desired concentration in the water distribution using a pump. So 4% solution of sodium fluoride is injected to the water. In dry feeder, the sodium fluoride or silica fluoride in the form of powder is introduced and dissolved. So here it is a solution, here it is powder. That's why dry feeder is a saturated system. And solution feeder is volumetric pump permitting the addition of a given quantity. So we use a pump, volumetric pump and put hydrofluorosilic acid in proportion to the water what we are going to treat. So this is a volumetric pump mechanism. And dry feeder is different where we add powder into this dissolving basin and saturator is solution we inject with a pump. So what are the advantages of water fluoridation? Because it can give benefit to a very large number of people because it is mixed in a community water supply. An entire city can be prevented carries by 50% each. So it not just act systemically but also it has a topical effect through the release of saliva. So it has definitely a systemic effect. It enters to the blood circulation and it goes to the teeth formation. Similarly, it has a saliva effect. So it always keep replenishing the lost minerals or lost fluoride from the tooth. So it has a topical and systemic effect. So fluoridation of community is a least expensive way to provide fluoride to a large group of people. So it is a least because even though it has a very big amount of installation cost considering the large population it serves it becomes the least expensive way. But on the other side, we have some disadvantages and one is the ethical issue because ultimately, once we start the community water supply all the people in that community are bound to drink that water. There is no choice of rejection. If I don't want to drink that particular water for any reason, I can't do that because the water supply is coming to my house and I'm bound to drink that particular water. So human rights is violated here. The right to reject is violated. The ethical issues are there. And we have other modes which is not considered here. And common source of water supply if it is not there, this is not possible. It has to be. There has to be a central supply of water. Then only this will be possible. So what we have seen is a community water supply. That is a community, a common centralized water is mixed with fluoride by any of the methods dive feeder, solution feeder or the saturator feeder system. And all of the community people drinking that water. The next is cool water fluidization. Now we are mixing the fluoride to the school water tank. Okay, so school water fluidization. In the beginning I told you the amount of PPM will be high because the number of hours a student spends in the school is less and the amount of water he drinks is also less. So to get a one PPM net effect he has to drink a water with as more PPM or 3, 3.5 PPM water if he drinks then only that one PPM net effect he would get. So usually three to four, four to five PPM. So it ranges between three, four, five. So usually these are the reasons because of the short period of stay at school to compensate for holidays and vacations. So it first started in 1954 at St. Thomas, St. Virgin Islands. So there it started. So it has to be at a higher level of PPM. So we can give four to five PPM to compensate their shorter period and holidays and vacations. So usually we give four to five that's 4.5 times or four to five PPM. Normally it is one PPM so that would be four or five times more. So it also gives a reduction 20 to 25 to 40 percentage. So advantages, good result, minimal equipments and not very expensive. But the disadvantages, children's do not receive the benefit until they go to school because they go to school by the age of five. By that time most of the teeth are already mineralized. So we are not able to use the pre-reactive mineralization cycle. That is the ultimate aim of this systemic fluidization because we have to get fluoride incorporated into the tooth while it gets mineralized so that finishes by six years or seven years. So what if the child goes to school at five years? So most of the teeth maybe molars and pre-molars are already mineralized. Left is a second molars and canines. So the major portion of the major parts or the major tooth are already mineralized. So that is the one problem and next is not all children go to the school. Some from the poor countries and towns, villages they don't go to the school. So amount of water drink also can't be regulated. Some people drink water, some people don't drink. Students drinking habit is not regularized. We can't monitor it. So some people may get the benefit, some people may not. So all these problems are there with regard of this school water fluidization. So next we have salt fluidization. Salt fluidization is started by WESPE in Switzerland, 1948. So in 1955 onwards they started selling fluoride salt. So usually sodium or potassium fluoride is mixed with salt. So it is like 90 milligram of fluoride per kilogram of salt or 250 to 350 milligram per kilogram. So it can be added by two processing known as one is batch processing and the continuous processing. So for the better caries prevention, fluoride must be present in ionic form when salt is dissolved in water. That is sodium chloride. So it should be ionic form. That fluoride has to be at its ionic form when the sodium chloride is dissolved in water then only the caries prevention will happen. So we can, there are essentially two different salt production process like batch processing and continuous processing. So one method is fluoride is added to the salt by spraying concentrated solution of sodium fluoride or potassium fluoride. So the solution is directly spread to the salt. Sodium fluoride or potassium fluoride we spray it on the normal salt or we have granules of sodium fluoride and calcium fluoride. So premixed granules of sodium fluoride and calcium fluoride with phosphate are added to the common salt. Either the granules are just spraying. So advantages it is safe and it does not require community water supply as in case of water fluidization we can, there's no need of any centralized supply and it has no ethical issues. If somebody doesn't want, he can reject it, it's low cost. So all these are the advantages and disadvantages. The main problem is sodium is always associated with hypertension and there is international effort to reduce the intake of sodium and there is no precise control how much salt it varies from person to person. So we cannot just regulate the amount being consumed. The next one is milk fluidization. It started by Ziegler. Salt was started by Vespy. This was started by Ziegler and both are in Switzerland, okay. So this is like mixing fluoride into water. So it gives additional benefits because already milk has some benefits. It gives calcium and vitamin D for kids along with fluoride also will be added beneficial. Rational is nothing but the nutritional value and it gives, milk products are very good for their teeth and bones. So added benefit will be given if it is fluoridated. So how we distribute milk? We can distribute through the school system and like school milk program or such programs will be there for kindergarten or nursery schools. So either fluoridated milk can be produced like one liquid pasteurized and sterilized or powder can be mixed into this milk. So just like salt, continuous and batch processing is there, milk also we can either use in a form of liquid or powder. So all these are the products which can be used, calcium fluoride, sodium fluoride, isodium monofluorophosphate and disodium silicofluoride. So after that we have fluoride supplements like tablets, drops, lozenges. So these are not commonly available over the counter but can be prescribed by dentist or pediatrician. So it has to be, these all are supplements, most commonly used is sodium fluoride. It has to be at a range of 0.25 milligram or 0.5 milligram or one milligram and they should be taken on a daily basis. So this is a chart which we can, which can be used to calculate the amount of fluoride we given to a particular child. So this is the amount of fluoride existing in the fluoride water, that is the water which we drink or the child drinks. So if the particular child drinks water with the amount of less than 0.3 ppm and his age is less than six months, we don't need to supplement anything. And if the age between six months to three years, we can give 0.25 gram additional and up to six years, 0.5 gram and six to 16 years, one gram we can give additional. And if the water supply is less than six ppm and greater than 0.3 ppm, we don't need to supplement up to three years, three to six years we can give 0.25 and six to 16 years we can give 0.5 gram supplement additionally. If the water drinking water has more than six ppm, we don't need to supplement fluoride for that particular child. So there are so much benefits for these tablets, losenges and drops which gives a reduction 16 to 65% age because it has both systemic and topical effects. We should always take precautions because of the toxicity because toxicity will be covered in detail on the next video. So that's all about fluorides that is systemic fluorides. I was explaining about the various fluidization studies and various mechanisms. Studies were important and why and how this is getting into this tooth lattice at what age it gives the protection to six years why systemic fluoride works. Beyond that, it won't have any much effect because teeth mineralization of tooth will be completed almost two second molar completed by six to seven years. So why this fluoride ppm is different for water fluoridation and salt or milk fluoridation. This is community water fluoridation as one ppm but school this salt milk has four to five ppm because the amount and duration of consumption is very different compared to community because community we will be drinking 24 by seven unlike school salt or milk fluoridation and various studies. We have many studies all we need to remember the intervention city control city, the year, the duration and the percentage of protection. Then the fluoride equipments how we add fluoride into community water supply that is dry feeders solution feeder and saturated methods and various advantages and the disadvantages for water fluoridation will be four to five ppm that is four or five times greater and why the reason it was started in 1954. Next is salt fluoridation and batch process and continuous process. It's advantages and disadvantages milk fluoridation. It's advantages and liquid and powder application and various methods, droplets, lozenges and tablets. It should be daily taken and this table given by American Dental Association if drinking water has dismissed ppm we should supplement this amount of ppm to get maximum protection against chemical carries. Okay, so that's all about system fluoridation and system in fluidation. The unfortunate part is nowadays very few countries are following system of fluidation because researchers has confirmed that the net effect of water fluidation and topical fluidation is almost same. The carries reduction is almost same for water fluidation and that is system of fluidation and topical fluidation. System fluidation requires a lot of installation charges where topical fluidation can be achieved by a single toothpaste. So why to waste so much investment time and manpower for community water fluidation and it violates human rights. So from 1970 onwards, most of the system in fluidation that is community water fluoride plants were closed because of the ethical issues and installation and maintenance charge. And nowadays the topical effect is more concentrated than the systemic effect. Because most of the time we think about systemic effect but nowadays the researchers are stressing on the topical effect because to always keep an amount of fluoride in the saliva and GCF that gives a continuous protective effect against carries than the systemic effect. But that was a very recent invention but still 1970 was believed that the water fluidation was the best method. And that's all about systemic flow. Today we have a new topic in fluorides. So that is topical fluoride methods. So basically there are two methods to apply fluorides. One we have covered already that is systemic methods. So that is like we consume fluorides as any compound or through water fluidation or through salt or milk. So it enters our blood circulation and get the benefit. So it goes to the teeth and bonds and it replaces the ions in tooth. It replaces hydroxyl ions and makes the enamel lattice very stronger. So by it creates a carries protective enamel. That is the mechanism of systemic fluoridation or how the fluoride helps tooth to prevent dental carries or a better tooth compared to the non-fluoride that tooth without any fluorides. So whereas in topical methods, it is entirely different because teeth has completely mineralized. So we are applying the topic applying the fluorides on the surface. So this can be applied after the eruption of teeth but the systemic fluoridation methods can be done or can be performed even before the eruption of teeth. So it goes to the teeth structure while it getting formed. So teeth eruption happens very late because most of the teeth that is up to second molar get mineralized by the age of six or seven but the second molar erupts at 13 or 14 age. So systemic fluoridation should be done before six to seven years. And topical we can do at any time. Mostly we do on the recently erupted teeth. Okay, so by definition, topical fluorides are the delivery systems which provide fluoride for a local chemical reaction to the exposed surfaces of erupted addition. So the indications are here is active individuals recently erupted tooth and people taking radiation therapy that can affect their salivary flow and a periodontal surgery. Where the routes are exposed. So how can this topical fluorides be applied? So basically it can applied via a profession like a professional can do it if we go to a dentist and we can do from our home itself. So topical fluorides professional application was introduced by BB in 1942. So we know in systemic fluorides we give just one PPM or four or five PPM, not more than that. But here we are giving 5,000 to 19,000 PPM which is equivalent to five to 15 milligram fluoride. Why is that difference? Because in systemic is giving at very low concentration as it is entering into our bloodstream and it is affecting the mineralization stage of tooth. But topical we are giving on the top or on the surface of the teeth where we are using the post mineralization phase. You basically a tooth has pre eruptive mineralization and post eruptive mineralization. So 90% of the total mineralization belongs to pre eruptive. So we are utilizing systemic fluorides by this pre eruptive mineralization and just 10% post eruptive mineralization is a topical fluorides target. So we need to increase the PPM to very high. Then only we get a net effect of one PPM because one PPM is optimal effect to prevent endocardies. So if topical fluorides needs to be at a net effect of one PPM it should be given at very high range because we are giving at a topical side and more than that just 10% H utilization of the post eruptive mineralization. Okay. So that is professional application. Self application we commonly use identifies as most of the identifiers as fluoride and we can use mouth princess gills. So it has basically less fluorides compared to the professional that is 200 to 1000 PPM. Still it is very high compared to the systemic circulation. So the reason I already explained to you it was invented by BB in 1942. So what are the basic sources of topical fluorides? The first one is toothpaste, mouth princess, professional applied gills, form princess and even our saliva as fluorides. So toothpaste we can apply it while brushing. Mouth princess like gargling, we can do gargling. Forms can be applied by a professional. Gills can be painted or using a mouth guard. So fluoride vehicles, how professional application of fluoride done is using a fluoride vehicle that is aqueous solution and gel. So the property of gel is which adheres to the teeth and eliminates the continuous wetting. If it is a solution, we need to continuously wet the tooth but if it is a gel, it adheres to the tooth and a continuous wetting is not required. And thixotrophic solutions, which are special type of gels. It's not a normal gel, but a special type of gels. So what is that speciality is it has high viscosity under storage conditions and it becomes fluid under condition of stress. So when we apply it to the tooth, we apply some pressure, it becomes fluid and it enters to the end of spaces. So that is thixotrophic solution. This is a fluoride vehicles, commonly used in professional methods. And we have seen a prophylactic paste. So it has fluorides. When we do prophylactic, the tooth might lose it's a little bit of fluoride content from the top layer. So it can be replenished if you do a post prophylactic paste application. And foam is like it minimizes the risk of fluoride over dosage and maintain the efficacy. Okay, so foam we can apply. So it is basically lighter than conventional gel and very little amount is required. So it can be easily penetrated into the intraproximal area and it doesn't require any suction. That is the biggest advantage of foam application. Next is fluoride varnish. Commonly we have two types of varnish. The one is giraffeette and fluoroproductor. So the advantage of varnish is the increasing the time of contact between enamel surface and the fluoride agent because it adheres to the tooth surface for a such a longer period. So there is a lot of time for action of this fluoride agents with enamel surface. So giraffeette is a product with 22,600 ppm and fluoroproductor is another product which has less ppm, that is 7,000. Sorry. And karex is another fluoride concentration which has lesser than giraffeette but has equal efficacy, which is one of the product we used for prevention of dental caries. So fluoride application, this is a paint on technique. This is how we do painting. So it's just like using a brush, we paint the teeth surface. So fluoride toothpaste, the commonly available toothpaste contains fluoride. So fluoride toothpaste are into the market around 50s and 60s. So once the fluoride toothpaste are into the market, slowly the systemic water fluidization is vanished from the history because most of the plants were closed because the effect of systemic and topical wear in preventing dental caries were almost same. So I had to spend a lot of money for installation of a systemic fluidization because we have seen already how much cost it requires for a plant setup. So the same effect can be obtained by using a toothpaste. So salive also has fluorides. So let's see what are the basic three solutions commonly used in topical fluids that the first one is neutral sodium fluoride sedulated phosphate fluoride or IPF and stannous fluoride. It can be applied either by paint on technique. So this is a paint on technique. We paint on the teeth surface by using a brush or tray technique. We apply the material, we load the material into tray and apply it. So aqua solution can be painted and the viscous gel can be used in a tray. So let's see what are the three methods, three compounds. So the first one is neutral sodium fluoride. So for that is 2% of sodium fluoride which gives a reduction of 30% of dental caries. So it is prepared by dissolving 20 grams of sodium fluoride in one liter of distilled water. So 20 gram we put in one liter, we get sodium fluoride. So that is known as Knudsen's technique. So the basic procedures are, we have to clean the teeth and apply it for three to four minutes. We leave it for drying for three to four minutes. So it gets its maximum concentration. So beyond four minutes, there is no point but the maximum concentration of this fluoride on the tooth surface can be obtained within four minutes. But the procedure has to be repeated at different intervals. That is a second, third and fourth application will be there after one week interval. So we have to apply at one week interval. So there will be four times application of this Knudsen's technique that is 2% sodium fluoride. So this four visit procedure is commonly seen in three, seven, 11 and 13 years because it coincides with the eruption of different groups of primary and permanent teeth. This is very important because at three years, there is primary molars, seven permanent incisors and molars, 11 and 13 canines and primolars. So this has to be applied on recently erupted tooth to utilize the 10% post- eruptive mineralization. So the advantages of neutral sodium fluoride are it is basically stable product and we can store it in a plastic container. Taste is well accepted by the patients and it is non-irritating to gingiva. It does not cause tooth discoloration. But the main problem is it has to be repeated at four intervals of one week gap. That is the most commonly reported disadvantage of this neutral sodium fluoride because it is not applied annually or semi-annually. It is applied at week intervals and that has to be at four times. There should be application at different age groups. That is three, seven, 11 and 13. If it is applied for the same person, it has to be done 16 times. So each year, four times at one week interval. So the second practice, stannous fluoride. So it's most commonly used at eight percentage. So the two percentage sodium fluoride or it is known as neutral sodium fluoride. Second one is stannous fluoride, eight percentage. So this is prepared by 0.8 grams. It's dissolved in 10 ml of distilled water in a plastic container and it has to be prepared freshly. And there is no stability. If you're using it for a patient, you have to prepare it at the moment and use it. You cannot prepare and keep it for the next patient. So it is like 0.8 grams in 10 ml of water, whereas sodium fluoride was like 20 grams in one liter of water, 20 grams in one liter of water, whereas stannous fluoride is 0.8 gram in 10 ml of water, okay? So technically same, you have to keep it for four minutes. You have to dry the tooth, keep cotton rolls, isolate it properly, then apply it for four minutes. So it reaches its maximum concentration and you can repeat the application at every six months, not like one week interval for four times like we seen in sodium fluoride. It has to be applied for twice, that is six months interval for the one patient. There is no age category, what we have seen in sodium fluoride. So the four minute theory I told you because the amount of fluoride reaches on the top of surface by four minutes. So even if you apply for eight minutes, there is no point, maximum concentration is achieved within four minutes. So four minutes is the ideal time. So advantage is only two application is needed unlike four applications. And the base, when the disadvantages are, it is not stable, you have to specially prepare for each patient and it is quite as stringent and its taste is a little odd and application is unpleasant. So there is a reports of tissue irritation and pigmentation of teeth. So none of these are present in sodium fluoride. So this is not stable and pleasant tissue irritation, arm gives pigmentation. So advantages are just like we have only one or two appointments in a year. So the last one is APF or acidulated phosphate fluoride. So it is prepared by 20 grams of sodium fluoride in one liter of phosphoric acid that is 0.1 molar, 20 grams in one liter of 0.1 molar phosphoric acid, then add 50 percentage of hydrofluoric acid and adjust the pH at three and fluoride concentration at 1.23. This is known as Brutfall solution. This is known as Muller's solution. This is Muller's technique. The first one was Knudsen's technique. Stannous fluoride is Muller's technique and the last one is Brutfall solution. So this is prepared by 20 grams in one liter, 0.1 molar phosphoric acid, then 50 percent hydrofluoric acid is added, pH three, concentration 1.23. Same method applies same way. There is just like a Stannous fluoride twice in a year and kept for four minutes. Commonly used in gels. So gel applied by Trey method. Sodium fluoride and Stannous fluoride apply by paint on technique, just like painting. This is applied in gels, that is Trey technique. So four minute period is also same here. On the tray, we apply the material into tray and keep it using a saliva ejector to control the water contamination. So this is Trey technique. We fill it one fourth of the tray height wise. Then we apply it like this Maxland mantable and keep it for four minutes. So advantages is just like Stannous fluoride two application in a year and gel preparation. Sorry, gel preparation is not like that sodium fluoride and Stannous fluoride where Trey technique is being used and the cost of application is reduced. Disadvantages is practical difficulties are there and it is very acidic because of pH three and it cannot be stored in glass. So just compare this percentage was 2% 8% and 1.23% of fluoride. PPM is 9,000, almost 20,000 and here it is 12,300. pH and sodium fluoride it was neutral. Here it was 2.4 to 2.8, almost acidic and it is also acidic. And sodium fluoride total 16 application for at one week interval at 3, 7, 11 and 13 in years that is four years each year for application total 16 application. This is bi-annually, this is also bi-annually. Stannous fluoride has a lot of disadvantages to pigmentation in gel irritation. Freshly need to be prepared very freshly like that and most of the teeth, most of the products gives a 30% age reduction. So the remaining products are dentifies small prints and gels, dentifies commonly we apply the most of the toothpaste as fluoride. And all traces we can give it for children under six years of age. It can be rinsed, it will give carries protection. Then methods is nothing but 5ML should be rinsed before bed and switch between teeth for a 60 seconds. Okay, so that's all about topical fluorides. So the most important things are these ones, sodium fluoride, stannous fluoride and APF. So stannous fluoride has most disadvantages and we need to remember this table, percentage, BPM and pH frequency of application. Okay, I'll come up with a new topic that is prevention of dental carries by fluoride in my next session. In topical fluorides video, I missed out a few things having mentioned about the mechanism of action of topical fluorides that is three techniques, sodium fluoride, stannous fluoride and APF. So in today's video, so I'll be explaining about the chemical reaction, the mechanism of these three techniques. So in Knudsen's technique, we know that we apply neutral 2% sodium fluoride and we applied for four minutes. It is, there is four applications on one week interval that is on second, third and fourth application will be at one week interval and it will be applied on age three, seven, 11 and 13. So there'll be a total of 16 applications. So let's see what is the mechanism of action? So how this topical fluoride of sodium fluoride helping the tooth to bite against dental carries. In systemic fluoride, we have seen the fluoride goes into the enamel and it replaces the hydroxyl ion and it creates a fluorohydroxyapatite or fluoroapatite crystals, which is very stronger than the normal hydroxyapatite. So let's see what is happening in sodium fluoride mechanism or Knudsen's technique. So when we apply sodium fluoride, what happens is this sodium fluoride, it reacts with hydroxyapatite crystal and to form calcium fluoride. This is a byproduct which forms calcium fluoride. So it start getting formed. The calcium fluoride is getting formed on the surface and a thick layer is formed at the end of four minutes. So what happens after that? This thick layer calcium fluoride interferes with further diffusional fluoride. So once this thick layer is formed, we apply sodium fluoride again and again. There is no point because this thick layer interferes with further diffusion. So there is no point applying sodium fluoride after four minutes. So that is why most of the topical fluorides are applying at a period of four minutes. So this particular process is known as shocking of effect. This is very important. It is seen in sodium fluoride. Once the calcium fluoride is formed after the application for a four minute spirit, it further prevents the diffusion of fluoride. So it blocks further entry of fluoride ions and it is known as shocking of effect. So this sudden stop of entry of fluoride is termed as shocking of. So this calcium fluoride act as a reservoir. So this calcium fluoride will be there on the surface and it slowly releases the fluoride. Okay, so it is not the sodium fluoride. It releases the fluoride for the prevention of tenderloin. It is actually the calcium fluoride releases the fluoride. So we might think that it is sodium fluoride is releasing fluoride, but no, it is the calcium fluoride. So calcium fluoride reacts with hydroxyapatite. Then there will be fluoride, hydroxyapatite, which increases the concentration of fluoride on nanosurface and proven caries. So from calcium fluoride, the actual fluoride is releasing out. Okay, not from the sodium fluoride. So that is a chemical reaction happening with the first topical fluoride that is nonsense technique. So all these techniques we have covered in detail in that video. So in this video I'll be explaining about the chemical reaction happening and especially this phenomenon known as chocking off effect. Chocking off means we are strangling someone and forcing or preventing his breath. So that is chocking off. So similar way we are strangling the further entry of fluoride. Because calcium fluoride act as a barrier and interferes with the further diffusion of fluoride. Okay, so let's see the second product that is tannous fluoride. So we are playing almost very high people that is 20,000 or around 20,000 ppm. So all these we have discussed already. So I'll be explaining about the mechanism of action. So when stannous fluoride is applied at a very low concentration, what happens is there is tin hydroxyapatite formation. Okay, so stannous is nothing but tin. It's a chemical name for tin SN. So tin hydroxyapatite is formed which gets dissolved in oral tissues when we apply in low concentration. So that is the scenario when we apply in low concentration. And when we apply at very high concentration, what happens is there is a formation of calcium trifluorostanate. So this stannous fluoride reacts with the calcium of hydroxyapatite and forms calcium trifluorostanate. At the same time, there is another product which is known as tin trifluorophosphate. So these two products will be formed once stannous fluoride applied at very high concentration. Okay, low concentration, there is no attraction, only tin hydroxyapatite forms. At high concentration, these two products are formed. The calcium trifluorostanate and tin trifluorophosphate. So this tin trifluorophosphate is responsible for making the two structure more stable. So this is the product which actually act as a barrier or prevents dental caries. Because this is a product which helps tooth to become more stronger than the normal hydroxyapatite. And calcium fluoride is the end product. So after this there will be end product that is calcium fluoride. In both low and high concentration which reacts with hydroxyapatite and a small fraction of fluorohydroxyapatite also gets formed. So same time along with this there is a very small amount of fluorohydroxyapatite because at the end product calcium fluoride is there. So it reacts with hydroxyapatite and fluorohydroxyapatite but very low amount. In sodium fluoride mechanism, calcium fluoride is the main product. Okay, but whereas in Muller's technical stannous fluoride this tin tri-fluorophosphate is the main product. There is a calcium tri-fluorostannate but this is the main product which helps the tooth to prevent caries or make it very hard. So that is the second mechanism of stannous fluoride or Muller's solution. So let's see what is acetylated phosphate fluoride or APF mechanism. So here what happens is when APF is applied to teeth in the beginning time, there is dehydration and shrinkage of hydroxyapatite crystals because we are applying it at very low pH. So it is applied at 1.23. Percentage at 3 pH which is very highly acidic. So it creates dehydration and shrinkage in hydroxyapatite crystals. After that an intermediate product known as DCPD is formed. That is di-calcium phosphate, dihydrate is formed. So this forms in APF. So always there is no need of confusion when we apply sodium fluoride. Calcium fluoride is formed when we apply stannous fluoride. Calcium trifluorostanate and tin trifluorophosphate is formed. We apply APF, DCPD is formed. So the DCPD is very highly reactive and starts forming immediately after APF is applied. So fluoride penetrates into the crystals more deeply through the opening. So there was shrinkage and dehydration. So this fluoride can easily penetrate into the deeper parts of enamel and forms fluoropetite. So this DCPD is a crucial product which forms when we apply APF. So this DCPD formed, which will be later converted into fluoropetite. Okay, so the compounds which are very vital in APF is DCPD, stannous fluoride which is trifluorophosphate and in sodium fluoride technique it was calcium fluoride and choking of effects seen in sodium fluoride. So these are the three techniques which we use to apply topical fluorides and the mechanism and its chemical reactions. So that's all about the mechanism of action which is associated with topical fluorides. So after that, we have seen all this, the comparison which we have discussed already, the pH percentage and all other things and fluorides. So I'll come up with a new video. So it was just an extension of our topical fluoride video just to give you a brief idea about the chemical reaction which is happening with the topical fluoride application. Thank you. Initiation of fluoride topics. So today we have a very small topic that is prevention of dental caries by fluoride. So we have learned various fluoride mechanisms like systemic fluorides, topical fluorides and its gross mechanisms like systemic, goes to the blood circulation. It enters to the mineralization stage and replaces hydroxyl ion and making it fluoro-apetite crystals. Whereas in topical fluorides, the mechanism is different because it uses the posterior demonization where this fluoride forms calcium fluoride by combining with the calcium of enamel and this fluoride will be available for further remanolization. So the mechanism is different. Where the systemic utilizes the pre-reptive mineralization stage which is a majority that is 90% of total mineralization and it has to be done before six to seven years because most of the teeth get mineralized before seven years. And post-reptive mineralization will be utilized in topical fluorides where the 10% of the mineralization will be used. But that is very critical because it is lifelong remanolization and remanolization will be happening in our tooth. Because our teeth in oral cavity are subjected to various pH and various changes in day-to-day life. So basically what happens when a fluoride is incorporated into teeth we have learned already. So in today's video I'll be explaining a few mechanisms whereby fluoride prevents dental caries. The first mechanism is fluoride increases the enamel's resistance and acid solubility because it replaces hydroxyl ion in the enamel lattice because it is a hexagonal shape which has a central void where the hydroxyl ion is located. Since fluoride is very highly electronegative it replaces the hydroxyl ion both are negative ions. So it replaces the hydroxyl ion and it fills the void which is present inside the enamel lattice and makes it very resistant to acid attack. So that is why it becomes resistant when there is acid challenge happens because it forms fluoropotate. You know enamel is a hydroxyapatite crystal. So this hydroxy ions that is OH ions will be removed and it becomes fluoropotate. So this hydroxyl ion that is OH ions is less electronegative than this fluorion. So this will be replaced and this fluoropotate will crystal will be formed. So that is why it is becoming very resistant and it is making acid less soluble. Whereas the second mechanism is the reminalization potential of fluoride. So if we add fluoride in our drinking water or if we keep fluoride in our topical or toothpaste or any solution gels form so on. What happens is fluoride will be present in the oral environment maybe in the gingival crevicella or saliva and it will be act as a reservoir to replenish the lost ions in the teeth. So day to day we may lose so much of ions because of our acidic food taking and our brushing or many factors we lose day by day some ions. But if fluoride is present in the saliva or GCF it can easily replenish the lost ions. So reminalization will be favored and there will be less caries chances. So topical fluoride also it has the advantages of presence of fluoride ions in the GCF and saliva. So it gives fluoride ions whenever there is a loss of ions from the tooth surface. So it always protects the tooth by providing fluorides whenever there is a reminalization. So reminalization potential is very important because every day it act as a reservoir inside saliva or GCF. And fluoride also has anti-bacterial effect because it interferes with the bacterial cell growth because it has inhibitive effect on the enzymes which are essential for cell metabolism and growth. That is rupto-hocus bacterial enzymes are destroyed or inhibited by this fluoride and it reduces surface energy of tooth and it can strip off bacteria from hydroxyapatite because fluoride can bind more effectively to positively charged areas on the appetite it serves than the bacteria. So obviously fluoride is beneficial. So if it attaches on the tooth surface and the bacteria is no place to be attached there is no platformation and ultimately less caries. So this is anti-bacterial effects. And the fourth point is increased rate of post eruptive maturation. So I told you already there are two phases of maturation of a particular tooth, pre eruptive maturation that is happening before the tooth erupts in total cavity and post eruptive maturation. And post eruptive maturation is critical because it is a lifelong process. Every day we have ion loss from the tooth surface and at the same time the ions are coming back to the tooth. So if the ion loss is becoming more compared to the replenishment then there is chance of caries. But the rate of post eruptive maturation is why it is important because this fluoride has a special capacity to re-mineralize the hypo mineralized areas. That is the biggest advantage. So wherever the tooth is not properly mineralized that areas will be soon or fastly re-mineralized by the help of fluoride. And the newly ruptured teeth we know the newly ruptured teeth are still need to get mineralized by 10 percentage. So these teeth can attract fluoride very easily. So we should apply fluoride always to the newly ruptured teeth. That's why fluorides are applied onto the newly ruptured teeth. In Knudsen's technique we have seen it is applied on 3, 7, 11, 13. So all the teeth are like deciduous molars, permanent molars and incisors, canines, primolars. So soon the tooth erupts into the oral cavity we should apply fluoride because this fluoride will soon be uptake, soon will be taken into the surface because these areas are hypo mineralized. It get mineralized only after three years or two to three years. The complete mineralization happens. The post mineralization happens right after two to three years. And there will be a lifelong remineralization, remineralization cycle. So we have to use that potential. Once the tooth erupts into the oral cavity we should apply fluoride. That is why we are applying topical fluorides into the recently ruptured teeth. And the last mechanism is modification in tooth morphology. So it has seen that people who consumed fluoride water as changes in the diameter and custom depth compared to the people who have not taken fluoride water. So it reduces the occlusion depth and occlusion cavity will be lesser and lesser chances of carries. Because of this improved morphology of occlusion surface can be attributed to the lesser amount of carries. So the diameter and custom depths are smaller if you already is present. So this is a very small topic. These mechanisms are the real reason why the fluoride prevents dental carries. So these were the mechanism. The first one was it increases enamel resistance to acid solubility. There will be less acid soluble enamel. Then there will be remineralization. There is antibacterial effect and increase rate of that is in hypomenalized area that is increased rate of post eruptive menstruation and there will be modification in tooth morphology. That's it. I'll be explaining about various de-fluidation techniques which are commonly used by the Indians. That is 15 out of 30 states have affected with fluorosis. So the common practices which are seen in India is explained in this video. So I have explained you about fluoride as a double H sword in my fluoride toxicity video because once it is going low, it can cause or it can attribute to formation of dental carries. And if it is going high, it causes fluorosis. So in 1984, WHO guidelines suggested that there should be one PPM for the optimal fluoride, one PPM should be the optimal fluoride concentration. So as to get the maximum benefit of it is to prevent dental carries. So if it is a warmer climate, the PPM can be low around 0.7, 0.8. And if it is a cooler climate, it can go up to 1.2. So the range varies between 0.7 to 1.2 because it is affected with the temperature. So we have already learned the motling because in the history of fluorides, we have seen the motile enamel. If it goes higher, the motling and discrete witting will be seen. So if it goes one, two, three, four, five range, it causes a severe destruction of the tooth. So for your information, the highest naturally occurring fluoride is recorded in a lake in Kenya and the lake is known as Nakuru. And it has 2,800 milligram per liter, that is 2,800 PPM. So we are talking about one, two, three PPM, but this lake has 2,800 PPM. This milligram per liter is PPM. So India has 15 out of 32 states that includes unit territories. We don't have 32 states, as such it includes unit territories. So 15 of total these states and unit territories are affected with fluorosis, that is endemic fluorosis, which is present for a very long period because groundwater has high amount of fluoride content. So in India, in USA, we have seen the community water fluidizations where happened in many cities, but in India there is no possibility of community water fluidization because we are suffering from the excess amount of fluorine or the fluorosis. So we are always thinking about de-fluidation, not the water fluidization, because we are at the other edge of the fluorine because we are getting disadvantage out of fluorine. So mainly the Gujarat, Rajasthan, Andhra are the 50 to 100% of the district in these states are affected. In Kerala, it is Alpi and Palakkad were affected mostly, but in these states have a severe attack of this fluorosis, that is almost 50 to 100% districts are affected. So let's come to the point that is de-fluidation. So what we are doing is we are removing fluoride from the drinking water, that is the idea behind de-fluidation. So what we can do is, either we can remove the fluoride from water or you can go for an alternative source of safe water. And bring water from a very distant sources. So those are the options we have, but the most convenient and most feasible method is de-fluidation, that is remove the fluoride from the water we have. So we have few methods, de-fluidation, and by definition it is the downward adjustment of level of fluoride in drinking water to the optimal level. So we have learned fluoridation is upward adjustment. So we are increasing in community water fluidization, the upward adjustment of fluoride, but whereas in de-fluidation it is a downward adjustment of level of fluoride in drinking water to the optimal level, that is one PPM. So we have the common methods as adsorption technique, ion exchange technique, precipitation technique and some techniques known as reverse osmosis. So adsorption is keeping some material in the water and the fluoride will be adsorbed to the surface. And exchange is replacing the fluoride ions by cation and anion. Precipitation is just like our water purification method. We add alum lime and bleaching powder and precipitate the fluoride by making it a flux. Okay, so this precipitation method is the most common, also known as an Alganra technique, which is almost same as our water purification or the process which we have seen in the water plant, the flocculation, sedimentation, filtration. All those procedures are same in this precipitation technique. So water purification is almost same. So let's see one by one. First one is adsorption technique. It is nothing but adsorption of fluoride ions onto the surface of an activation. We put some active agent into the water and get the fluoride adsorbed, not adsorbed, adsorbed on the surface. So the material used are activated alumina, activated carbon and boncha. Boncha is nothing but bones of these dead animals. So it has a property to adsorb this fluoride. Okay, so activated alumina, alumina which is launched by UNICEF in rural India because rural India is mostly affected with fluorosis. So alumina can be inserted into the water and it adsorbs the fluoride. But the most problem faced with this alumina application is adsorption of fluoride only at specific pH range. So we have to check the pH range, whether it is suitable for this alumina application or not. And there is always a pre-post pH adjustment of water. Water should be at a proper pH for this alumina activation or alumina application. And there should be frequent activation of alumina is needed which makes a technique very expensive. So once we use alumina, it needs to be replenished. The active ingredient will be lost after a period of time. So it needs to be replenished or frequent activation is required. So these are the disadvantage of alumina. So bone char as the same process, bone char we put into the water and it absorbs fluoride. But the problem is it depends upon the temperature and pH of the water. But it is economic, bone char are economic because it is maybe available, not like activated alumina. But the main problems are it can harm the bacterias and it is an hygienic method and it is very technique sensitive. And the biggest problem in Indian scenario is the cultural and religious objections. We take bones of the dead animals. It may cause problems considering the cultural sentiments. So the next thing in adsorption technique is brick pieces column. So it is almost like activated alumina. So it has an agent compound is the compound which is present in the brick column is alumina oxide which absorbs fluoride. And also mud pots also can be used to remove fluoride. So water which is kept in mud pots the mud pot will receive or it absorbs the fluoride. And it is one of the common method which is used in the rural part because of its economic point. And it is commonly used, commonly accepted in rural community because mud pots are easily available and it is cheap. So there are some natural adsorption. Adsorbents like drumstick tree, seeds of drumstick tree, roots of vetiver grass and tambourine seeds. The MS Swaminathan Research Foundation that is MSS RF had shown that this drumstick seeds to have a remarkable defluidation efficiency which is higher than that of activated alumina. So which is all natural adsorptions. We have drumstick seeds, roots of vetiver grass and tambourine seeds. So these also can be used as an adsorbent. So these were the adsorbing techniques. So we had seen this natural adsorption, adsorbents and mud pot brick pieces, then the bone choice activated alumina. So the next we have ion exchange method. So ion exchanging method is using of synthetic chemicals namely anion and cation exchange. So the problem with this technique is it is very expensive and uneconomical in Indian scenario because Indian scenario this pleurosis is mostly affected in the rural areas and they cannot afford this type of equipments and this ion exchange techniques. They're all convenient with the adsorbing techniques. Till the Nalgonda technique has come into practice. So one of the ion exchange technique the compound used is carbion. It is a cation exchange resin. So it can be used on sodium and hydrogen cycle. So it exchanges the cation whereas a defluorone one and defluorone two are different one. So defluorone one has, it is a sulfonated sodast which is mixed with two percentage alum solution. The defluorone two was developed later to overcome the problem of defluorone one. It is sulfonated coal using alumina solution. Okay, first one was sodast whereas the second one was coal. Both are sulfonated. So that was a very expensive method. This carbion, defluorone one, defluorone two the ion exchange method. So the ion will be exchanged either the cation or anion. The ion of this fluoride compound or this fluoride will be because fluoride and ever stays as a ion it always exists as a compound. So the product we apply will replace this ion or it exchanges the ion and reduces the fluoride availability or the presence in the drinking water. So make it to a drinkable condition. So this is not used because of its expensive nature. And the most common method we use is a precipitation technique. So disadvantages of ion exchange engine and adsorption techniques we have seen because there need to be a necessary flow system. And it is often difficult to arrange if there is no pipe to water supply if people are taking water from the wells or rivers or something like that. Ponds or such water supply. This is not possible. The two methods which I explained already are not run with this well system. There should be a flow system that is it should go through the pipes and this equipment should be connected to the pipes. And there should be and this is an active agent. So there should be frequent activation of the agents. There should be replenishment of this agents otherwise the water won't be get the flutation. But the precipitation methods are based on the addition of chemicals such as coagulants and precipitating the soluble fluoride as insoluble fluoroapetite. Okay, so it's just like what we have seen in water purification method. The big tank we add alum as a coagulant and it coagulate the impurities and the flokes are getting sedimented and it removed from the bottom of this chamber and then it goes through the filtration. It's the same principle as being applied in Nalconda technique except some extra agent will be added here. The Nalconda technique of flutation is almost same as water purification and it was invented by NERI that is National Environmental Engineering Research Institute in Nagpur and it was by Nalke et al in 1974. It was very economical and simple method. So why this Nalconda name came because Nalconda is a district in Andhra Pradesh where they used this technique as indigenous method. Later this institute has taken up this method and commercialized and they started building this plan for this rural people. But Nalconda is the area where this technique was in its primitive fashion. So they started it. So the name was given as Nalconda technique. Nalconda is not in Nagpur, it is in Andhra. Okay, so what they're doing is they are adding sequence of sodium aluminate that is alum, lime and bleaching water to the fluoride water. Then do the flocculation, sedimentation and filtration just like our water purification. So in most commonly, we add alum to the water purification plant or water fluid purification in the first step. Here we are adding lime and bleaching water in a sequence. So that is the difference in between this water purification and Nalconda technique. So it can be very useful for domestic and the community water supply. So this is just a flow chart. What we are doing is lime, alum and bleaching water will be mixed to the first point of entry and there will be a rap mixing. This is flocculation, then there will be sedimentation. The sediment will be removed from the bottom of the chamber and this goes to the filtration. So filtration slowly it get filtered and it goes to a clean water tank. So the process is almost same as water purification. Only thing is it has a different reagent, lime, alum and bleaching water. So mechanism is it all commonly run for a 22 liters of water. The first we do rapid mixing that is coagulant will be added to this water then 30 to 60 seconds with the speed of 10 to 20 RPM. The coagulant is rapidly mixed so it gets uniformly dispersed. So it start getting microflogs of fluoride because of this chemical coagulant. Then flocculation is the second stage where it is RPM is two to four. The beginning it was 10 to 20. Now it is slowly run for 10 to 15 minutes. The rapid mixing was 30 to 60 seconds. The flocculation it is slowly do the rotation and it started forming the flocs because of this coagulant, the fluoride compound will get become, will become flocs and it's starting sedimentation. So due to this gravitational force this particles will be sedimented at the bottom and it will be removed. Okay, as we have seen in the diagram. So we add here, we do the rapid mixing then for flocculation this is 10 to 20 RPM, two to four RPM. This is for maybe one minute, this is for 10 to 15 minutes. Then it goes to sedimentation. This is the sedimentation time here. It is slowly for 10 to 15 minutes and two to four RPM. Then this sediment, this floc, flocs are removed from here because flocculation happened here flocs are removed from here. Then it goes to the filtration and filtration and finally we get the clean water. So filtration is same like our water purification plant. So it get filtered and we can send it for the domestic supply. So maintenance is very cheap. It is like 1.6 lakh for a 250 population and only we need 50 stainless steel filters and it is costing around 35,000. So the main advantage, it's its low cost of investment and low cost of maintenance. So the biggest advantages are there is no need of regeneration of media which was seen in the adsorption techniques. No handling of caustic acids and alkalis. The chemicals are required are readily available and it can be used for domestic use, economical, simple design, construction. We can use a very large quantity of water which is very efficient removing flow rate from high levels and very little wastage of water and needs minimum mechanical and electrical equipments. There is no need of energy, only need muscle power. Semi-skilled workers also can be used. So the biggest disadvantage is if the total dissolved solid exceeds 1,500 milligram per liter, we need to do a prior desalination and hardness of water also matters. If it is 200 to 600, it requires precipitation softening and if it is beyond 600 milligram per liter, it needs becomes a cost for rejection. Or adsorption of desalination. So there will be a high amount of sledge compared to the other methods in the algorithm. And there is a requirement of a large amount of alum. So indications should be total dissolved solid should be less than 1500 milligram per liter. Total hardness should be 600, below 600. This should be below 1500. And raw water flow rate should be between 1.5 to 20, that is 1.5 to 20 ppm. Modifications are like polyaluminum chloride is another compound. Polyaluminum hydroxy sulphate also can be used. And the other methods are reverse osmosis, electrolysis or electrolysis are the physical methods that are tested for de-fluidation. So these methods are also can be used for a very small amount of water. So reverse osmosis is like we use hydraulic pressure exerted on one side of a permeable membrane. We have seen it in our younger classes, what is osmosis, what is reverse osmosis. We keep a semi permeable membrane and apply hydro hydraulic pressure, which forces the water across the membrane and leaving the salt behind. So leaving the salt or fluoride behind and get the clean water on the other side. In electrolysis, the membrane allows the ion to pass but not the water. Okay, so our idea is to remove the fluoride from this water. So we can use a reverse osmosis, keeping semi permeable membrane. Or in electrolysis, the ions will be passed and the good water will be left out. And electrolysis is also very expensive and intensive procedures. But it is very rarely used all these. Reverse osmosis, electrolysis techniques. Electrolysis also it is a process with adsorption of fluoride with freshly prepared aluminum hydroxide, which is generated by anodic dissolution of aluminum or it's alloy in electrochemical cell. We have learned in chemistry what is anode what is cathode, what is electrolysis. So once electricity passes this ions moves to anode and cathode. So that procedure also can be used to remove fluoride from water. Biggest advantage is it doesn't need any chemical and no need to pre and post treatment. Low volume of sludge, but it is required, there is a requirement of electricity. So that's all about deflutation techniques because like I said, 15 out of total Indian states are affected with fluorosis. So we are into the action of deflutation not water fluidation because we are to remove the fluoride from the water to get people a palatable or portable drinking water. So far we covered fluoride's history, the systemic and topical fluorides, fluorides in prevention of dental caries and do deflutation techniques. So let's see the details about fluoride toxicity. Fluoride is known as doublet spot. So usually we know this spot we have seen in pictures and this was used for the meeting. Yes. Hello everyone. Welcome back to a new session on dentistry and more. Today we have a topic on fluorides and that's fluoride toxicity. So we have covered so far the history of fluorides, systemic fluorides and the topical and the role of fluoride in prevention of dental caries and the various deflutation techniques. And the last one is fluoride toxicity. So let's see the topic in detail. So fluoride is known as doublet spot. So usually spot will be having only one end which we have seen the spots in pictures. One end it we have a handle and other end is serving its purpose. So what if the sword has a double edge? So it can ensure with both the hands, both the ends. So that is a doublet sword. So fluoride is a doublet sword. Why? Because if the amount is too less and if the amount is too high, it causes problem. It should be at a optimal level. Just like a doublet sword, it can ensure a person with both the ends. Usually sword enjoys a person with only one end. So similarly the fluorides, if it is too low, the patient or the people may get caries. If it is too high, it can cause fluorosis either dental or skeletal. That's why it's known as doublet sword because fluoride should be at a optimal level for proper protection against dental caries. That is one PPM, one parts per meter. If it is less than that, patient has a chance of getting dental caries. That is one disadvantage. If it is too high, it causes skeletal and dental fruoses. That is a second disadvantage. So on either ends, it has disadvantages. So it should be at optimal level, that is one PPM. So the toxicity is broadly classified as acute and chronic. So don't forget the doublet sword concept of fluoride when it is low and when it is high, it causes problem. Okay, so the acute and chronic, as we all know acute is sudden, chronic is slow action, acute is very fast, just like a single ingestion of very large amount of fluoride. So that becomes acute. You know acute pain and chronic pain acute is sudden, pain and chronic is slow throbbing type. So similarly, the fluoride, if we consume very large amount in very short of period in a single shot, it's known as acute and chronic, very slow amounts over a longer period of time. So let's see what is acute toxicity. So acute toxicity, as we mentioned, a large amount ingestion in a very short of period or a single shot. So the speed and severity of response dependent on the amount of fluoride ingested and the weight and age of the individual. So it depends the prognosis or the outcome of the patient, depending on how much fluoride we consume and weight and age of the individual. So most common adverse effect is nausea and the patient may have abdominal cramps, dindaria and salivation, dehydration and thirst. So after two to four hours, better it is possible if first aid is not administrative. So the golden hour is first two to four hours. So we should do the treatment, give improper treatment or the emergency treatment at the first two to four hours. So usually death happens if the treatment is not given by cardiac failure or respiratory analysis. So that is acute toxicity, the symptoms and the golden hour two to four hours. So if the death is not happening after 24 hours, then the prognosis will be. So we need to learn the two doses here. One is certainly lethal dose, also known as CLD and safely tolerated dose, that is STD. So CLD is 32 to 64 milligram per kilogram body weight and safely tolerable tolerated dose is eight to 16 gram. So that is almost one fourth of the CLD. So that is the easy way to study the CLD and STD. CLD is equal to four STDs. Can just see multiply eight at 32 with four, 16 to four. We get 64. So certainly lethal dose is this per kilogram body weight if you multiply with 100, you get three grams, 3.226.4 grams KG. So 100 KG body weight needs a 3.226.4 grams because we are converting milligram to gram. Okay, so it becomes 3.226.4 gram of 100 KG body weight person. So if a person consumes 3.226.4 gram of fluoride, it might leads to death of the person. So on average, you can take five gram as your lethal dose. So if you consume five grams of fluorides, you might die. So that is certainly lethal dose and safely tolerated dose is one fourth of CLD. So we can say that if person has 100 KG, safely tolerated dose of the body is 0.8 to 1.6 gram. So this is milligram and I'm talking about gram because I'm talking about a person with body weight 100 KG for your easy comparison. So we calculated five grams here and we can say this one fourth, the safely tolerated dose will be around 1.25 gram can be tolerated by the body. So that is CLD and STD. Okay, so this will be if we calculate, we get five grams and this will be around 1.25 gram up to 1.25 gram can tolerated. We can tolerate, body can tolerate that amount and if it goes four times and it becomes five grams around five grams, patient or the person might die. So what we do if we face a situation of fluoride toxicity in our house or in a clinic or anywhere, anywhere around us where a person consumes a large amount of fluoride by mistake or any suicide attempt, what we are supposed to do. So first try to understand the difference that is we have three types of treatment that is if the amount consumed is less than five milligram per body weight and five to 15 and more than 15. Okay, so it is like if person has 100 kg weight, okay. So this is 0.5 gram, it becomes 0.5 gram and this is 0.5 to 1.5 gram and this is more than 1.5 gram. So we need to understand the amount consumed. This is just kilogram per body weight. So I am explaining about a person who is having 100 kg. So you can calculate if the person has around 80, 70 kg, it will be somewhere here, 0.4 grams or something like that. So if it is very less, just 0.5 gram, we need to give calcium because calcium binds to this fluoride. Fluoride is highly electronegative, the ion existing highly electronegative state that is F minus. So it will immediately react and bind to the calcium. Okay, so calcium fluoride will be found because it's very difficult fluoride to stay as an ion, so it always exists as compound. So if we give calcium, this fluoride will join with calcium and it becomes calcium fluoride. So it relieves GA symptoms and there is no need for induced vomiting if the person is consuming around 0.5 gram, less than 5 milligram per body weight. So what if the consumption is between 5 milligram to 15 milligram per body weight or 0.5 to 1.5 gram? Okay, all calculation I am referring with a person of 100 kg. So what we have to do is we have to induce vomiting using any ametic and we have to give the same oral calcium just like milk, 5% calcium, glutamate or calcium lactate solution and we should rush him to the hospital for observing for few hours. So vomiting oral calcium and taking him to hospital will be the treatment scenario if it is a moderate amount that is 0.5 to 1.5 gram. So what if it is very high dose like 1.5 gram? So we know lethal dose is 5 gram. So we have to take him to the hospital very immediately and induce vomiting and we should monitor the cardiac and we should keep IV, not orally IV calcium gluconate because absorption should be very fast and supportive measures and sometimes diuretics also we should keep. So if we don't know the amount consumed it's better to take him to hospital. And can assess the symptoms. If patient is very okay, if person seems to be okay, can assume that the amount consumed is mild or moderate. Person is not properly oriented and person has this vomiting tendency and dizziness. So all those symptoms you can rush him to hospital. So these are the various protocols for emergency treatment of fluoride exposure. So next is the chronic fluoride toxicity. It is commonly there are two types that is one is dental and skater for us. So chronic we know it is a chronic consumption or a very longer period of time, not immediate consumption and it doesn't need immediate treatment because it happens for a very longer period. So dental process we know the tooth optimal amount of fluoride in drinking water is one PPM. If we are consuming water with more than one PPM for a very longer period especially during the tooth development that is a highlight point tooth development that is less than six years old because the second one will be finishing its mineralization around six years. So if person consumes water with fluoride more than one PPM after six years, there are very less chances of fluorosis because most of the teeth completes its mineralization cycle. So if person consumes water more than one PPM during the mineralization cycle there are chances of dental fluorosis. So most commonly the fluorosis appears as white flex and chocky opaque areas on the enamel. Okay so most commonly it should be at one PPM and if it is going higher and higher the appearance will be changed. If it is two PPM or three PPM that is two or three times greater it will be white flex or chocky opaque areas where if it is going high that is four to five PPM it become brown and pitted corroded appearance that is severe fluorosis. That is about dental fluorosis that is in range one to five PPM we can say. If it is going very high more than six, seven, eight PPM our bones also will be affected. Usually all mineralized structure will be affected but mostly it is visible on the teeth if it is a very milder or the two, three to four PPM the skeletal structures also will be affected but we cannot make it very obvious because it is bonds we can't see the bonds. So the only calcified tissue we can see is our teeth so it is very visible on the teeth. So the visible changes that what we can see in our bonds is the crippling stage. It is very, very bad situation because the bonds will be crippled and its shape will be changed. So that is the only state where we can see the bone or skeletal fluorosis not like dental fluorosis. So it happens only when the fluoride amount is more than eight PPM. So symptoms will be severe pain in the back, bones, joints, hips and stiffness and there will be a special syndrome known as nocney syndrome because usually we can bend our legs and hands only in one side backward but we can do upward bending of legs and hands that is nocney syndrome. It is very advanced stage of skeletal fluorosis. So that's all about dental fluorosis and skeletal fluorosis which is seen in chronic fluoride toxicity and acute fluoride toxicity. It requires treatment, immunotreatment. These stages I mentioned under chronic toxicity. So fluoride is a double-edged sword if it is used at a proper optimal level that is around one PPM. It gives proper and a good protection against dental caries. So that's all about fluoride toxicity. I'll come up with a new topic in my next video. So thank you for watching. So that's all about fluoride toxicity. So we have completed the fluoride topics. So in my next session, I'll pick up a new topic. That's all about fluoride toxicity. So we have completed the fluoride topics. So I'll come up with a new topic on my next video. Thank you for watching.