 Welcome back to another revision session on dentistry and more. So today's session is about tools. So we have two confusing questions that you might face in your exam that is tools of dental public health and tools of epidermal disease. So what are the tools which is used for dental public health or a public health dentist and an epidemiologist. So dental public health we know that it is corresponding with the clinical dentistry. So clinical dentistry is concerned with treating one patient whereas public health dentistry is concerned with preventing diseases, oral diseases of a very large group of people. So that is dental public health or a public health dentist. So when preventing and promoting oral health of a very large group of people we need these tools. So the first tool is epidemiology. This is as per definition we know it is identifying and solving the diseases of people. The second tool of dental public health is biostatistics. So it is very difficult to reach into a conclusion by doing any epidemiological survey because we have a lot of data. So from this data to reach into conclusion we need mathematical analysis that is biostatistics. Second one is biostatistics and the third one is social science. So since we are dealing a big group of people we need to understand the sociology, the sociologies of psychology and all other social aspect of the people. And the fourth principle of dental public health is administration. So when we are applying a workforce into a big population to conduct a study there should be proper cautious measures how the workforce is being deployed, how they are categorized into various sections and how they are being managed. So administration is a big task otherwise we will end up without reaching into a conclusion by spending lot of money, time and workforce. And the last one is preventative dentistry that is the ultimate goal is to reduce the mortality of dental problems in a public. So we conduct epidemiology, understand the problem and reach into conclusion by doing biostatistics and the social aspect of people by doing a proper administration and finally we do preventive dentistry to prevent the problems of a public that is mainly the dental problems of public. So that is tools of dental public health or tools of a public health dentist. Now let's see what does the tool of epidemiology. So here the thing is epidemiology is itself a tool of dental public health and epidemiology further it has again three tools that is rate, ratio and proportion. So these things we have discussed in detail in our epidemiology sessions. Rate is different thing, ratio is different thing when our ratio is x is to y there will be two parameters proportion we take proportion and it will be mentioned in percentage. The most common proportion is prevalence that is how much area or how much people in a total population is affected with the disease. Rate is the speed, speed of progression. So I am just giving a recap on all these we have covered in detail. So the example is incidence. So we have seen cumulative incidence and incidence proportion and incidence density. So all those things we have covered in detail. So my idea is to give you a proper clear idea because when you study in this format you will never get confused while writing exam because tools you might end up writing the wrong answer so always never get confused. Epidemology is one of the tool of dental public health and Epidemology has three tools basically rate, ratio and proportion. Okay I will come with a new revision topic in the industry and more. Thank you.