email time it's email time oh man if you sent me an email in the last 10 days 14 days apologize that I have not written back yet it's becoming a little more difficult to reply to all of them in a well-thought-out detailed way and so I need to come up with a better strategy for answering your emails so thank you for your patience but yes I'm gonna sit down now and answer a lot of your emails okay did you see yesterday's vlog about the hoka carbon rockets oh my goodness lots of thoughts lots of different opinions coming in about this shoe but all in the comments about the shoe but also about hoka in general so it's exciting it's exciting thank you for watching that if you haven't seen it upper right hand corner and then don't you worry I have not forgotten about the Reebok float ride run fast pros oh my gosh that is a mouthful but basically as soon as I bought these shoes they it snowed in Denver these are the three ounce shoes remember that very lightweight shoe and I bought them and then it just snowed and it's been kind of slushy and grimy here in Denver and I just didn't want to take these shoes out in the slush and the wet and the snow so anyway the snow is melting quickly in Denver and hope although it might snow again Thursday we will see so I hope to take these guys out by the end of the week we shall see I'm just a little old-school YouTube I'm a little old school I so this is my marathon training calendar and listen of course I love Strava love Strava love connecting with all of you onto more global running by the way oh my goodness it's blowing me away I cannot I can't even fathom how impressed I am with your training how much vertical some of you are getting it's just it's amazing it's inspiring it is inspiring but I first like to I like to start with a physical calendar you saw me inside my house writing out the training log for the next two to three weeks just plotting it out plotting it out thinking and I live I have a pencil I have an actual pencil and so I'll write something in and then kind of back up and be like meh I'm gonna move this workout over here and the reason I actually sometimes I erase things with the pencil because of the weather and so snow is probably gonna roll into Denver on Thursday of this week which means I want to try and get as much vertical early in the week for this upcoming week so it's just interesting and that is why I like to write things out on this physical calendar and I will give you a little brief update on the marathon training how it's going and how the body is reacting to the different workouts even though it's not like track workouts yet but just the vertical gain and everything else the key word today is Elton that's right Elton for Elton John why is it Elton well basically what do we do here on YouTube every Wednesday night we livestream that's right we do a Q&A and eventually we will do live interviews but again today Monday I tried I did another test with my brother it did not work who knows and I'm not gonna stress about it not gonna worry about it someday it's gonna work but in the meantime it's just gonna be you and I we're gonna be talking on this Wednesday not at night not at night because I will be at an Elton John concert with my mom that's right we bought tickets six months ago and I kind of forgot about the concert up until like two days ago and so we will not be doing a live stream this Wednesday night instead shout out to Europe we're gonna do the live stream at noon my time which is basically 7 p.m. if not base it is 7 p.m. in London I think that's about 7 p.m. in Paris maybe Madrid and then the further east you go in Europe it'll be you know 8 p.m. then 9 p.m. and 10 p.m. I don't know all the time zones in my head but so 7 p.m. or sorry noon Wednesday we're gonna do a live stream right here in the studio come back for that okay moving on and this is by the way I am in ketchup mode after the last two days of filming editing publishing about the Hoka carbon rocket today is a little bit of a down day on YouTube a little bit of a administrative day could we call it that because basically this shoe is keeping me busy a lot of comments a lot of thoughts are coming in about the Hoka carbon rocket from all of you thank you for tuning in to the vlogs over the last two days like there's a lot of opinions being shared about the narrowness of the Hoka lineup the narrow fit of the Hoka lineup the 1 millimeter drop in this shoe just a lot of opinions and so I'm trying to respond to as many of the comments as possible which means my time is a little limited as far as filming today and I didn't get to film my run in the beacon and on Strava definitely I'd say at least two or three times a week people are people are asking me about the durability and listen I don't have 200 miles in the shoe yet but I have about a hundred miles but so far so good I think one person did say after they're approaching 250 miles in the beacon and it's starting to show a little bit of wear and tear through the outsole but at a hundred miles we're still good and I mean we're talking real good and I'm gonna get you some close-up shots right now no complaints about durability through the upper or the outsole in the beacon okay and I'll keep taking this shoe further I'll get it to 200 miles eventually and we'll just keep well I'll just continue to keep you updated but so far I'm excited alright put that guy up there moving on to a couple more points t-shirts are in there there things are moving in the t-shirt world I think I said mid-February it's we're I don't know if it's gonna be quite ready by February but shout out to a vlog fan from North Carolina he reached out to this gentleman reached out to me and said hey I do graphic design work I'd love to help you with your overall branding and I'm just telling you like that was music to my ears I love video production but graphic design is not my strong point and so again shout out to this vlog fan from North Carolina he we've already spoken on the phone and we've exchanged emails and ideas are flowing as far as overall logo design t-shirt design all that good stuff so that is an update for you on the t-shirts okay and a quick update on marathon training and what I'm about to share I really don't want it to like influence what you're doing because guess what you got to stick to your game plan right you know your body you know like how your body reacts to training and I know how mine reacts to training and so as you've seen on Strava I like to build that aerobic base ridiculously big that's why I do the mountain runs like just that not going in aerobic at all just that big aerobic base at slow paces and I'm okay with that early in the training block if you're you're probably you're probably worried like Seth when are you gonna start going a little faster because guess what marathons are right you know racing a marathon those guys are fast and I realize that but I also know that I can sharpen really quickly like I can sharpen I mean I my brother and I often talk about this like I can sharpen in oh gosh like three weeks like and I'm exaggerating just a little bit but when I took third place at the pike speak ascent I literally trained for seven weeks before that race and I think that's part of the reason why I did pretty darn well is because my legs were not shot to you know what they were still pretty fresh so early in this training block for the marathon I have started so it started January 1st so we did 30 miles the first week uh sorry 20 miles the first week 32 miles the second 45 the third 51 the fourth as far as miles sorry I'm not gonna convert it into kilometers right now uh 65 miles in the fifth week and this week I hope to hit 70 miles and uh last week I was able to get 10,000 feet a vertical gain and I did notice a couple other people on the demore global running you hit you hit 10,000 as well congrats that's awesome um and I'm a big fan of using when you're training for any race really um but especially the marathon using the geographical features around you to your advantage so if you live by a beach like you can do some beach training in order to work on the suppleness of your legs and the strength of your legs I happen to have mountains by you know close by so I like using the mountains to my advantage but if you live at sea level you can work on uh turnover because you can run faster at sea level you know there's more oxygen to breathe so you can go faster so anyway that's what I like to do I love to use the mountains to my advantage and so far uh last week I think it was Wednesday was the first day that I felt sore in this training block so it took me basically 30 days exactly to feel the first onset of sore legs which means again that being as patient as possible in that ascent of volume um and what I'm doing so I started off at 20 miles the first week what I'm doing is I'm going to ascend up to 90 miles per week by early March 90 miles per week and then I'm gonna race that that mountain run in in Aspen Colorado and then I'm gonna drop back down because I know again based on experience that my body cannot hold high volume for months and months and months and the race the Cleveland Marathon is May 19th and so what I'm gonna do after early March I'm gonna drop back down to 40 miles and then climb and rest rest just reset and then climb back up again um and I will start to add speed work mid-march so basically eight weeks before the marathon uh I'll start to add speed work and when I say speed work oh my god well okay we're not gonna get into that now but eight weeks out from the marathon I'll start to work on that turnover um in workouts and then uh by early May I'll be at pretty high volume pretty high volume um will it be 90 miles a week it will be and it might even be a little higher than that so anyway that's the game plan so far I'm feeling good that's my update on the marathon and if you're racing a marathon let me know down in the comments in 2019 that'd be amazing I let me know which one and that question of the day well listen we could talk about running and running shoes every single day but I also just like to get to know all of you better and so here it is and I thought of this last night as I was putting uh the juice back into the fridge what is something unique or strange that you do in your daily routine all right or in your life or in your maybe it could be connected to running like something unique or strange or different uh for example last night I realized wait a minute every single night I go to the fridge and I take a swig of pineapple juice I don't know that's kind of strange maybe it's just like that one last injection of sugar into the blood stream for the day anyway that's something kind of unique that I do every single day and so what is something that you do I'd appreciate it down in the comments just you know whatever you want to share whatever you want to share lots lots of good stuff coming lots of good stuff coming up this week lots of good stuff see beauty work hard


Here at the California Memorial Stadium. Last Saturday, the Golden Bears took on number five USC Trojans. Beginning in the first quarter, Ashton Davis received a kick return, taking it from the end zone into the 40-yard line. The second quarter, senior running back, Vick and Weary pushes his way from the fourth quarter to receive a touchdown for Cal, helping lead the Bears 10-3. Matt Anderson ends the half with a 21-yard field goal to tie the game. In the third quarter, the USC Trojans and the Bears were held scoreless, showing strong defense. We had good opportunities for touchdowns in the fourth to keep the momentum going, but Ross Bowers threw an interception and a fumble to disable the Bears from catching up and score. But with one minute and 53 seconds to go in the fourth quarter, Jordan Veezy catches the ball for an eight-yard touchdown from Ross Bowers to cut the deficit to a 10-point difference. Even with the loss, Cal outscored the Trojans 416 to 356 in total offensive yards. The Golden Bears will try and get back on track as they travel to Oregon for a 730 matchup this Saturday. Thank you for tuning into CalTV Sports. I'm Phoebe LeMay here at California Memorial Stadium. Go Bears!


Hello everybody! We're here to do our second lecture in our general biology course. This lecture is on the process of science. Our last lecture was on life. Biology is the study of life, sort of a fundamental concept leading into a class about life. Biology is a science class and having an entire lecture on the process of science I think is really important. I have to say that not only do I think learning about the process of science is important period in any science class, that's something that I've always felt, but I feel an increased urgency in ensuring that humans out there understand the process of science and what it does and what it doesn't do, which means we have an entire nine-part lecture just on this topic. We're gonna start out with some definitions. You'll notice that I have a website up right now and this website is one of my primary go-tos when I am looking for information about science. This site is phenomenal. It addresses the process of science. It has incredible resources, great diversity of different kinds of scientists, different kinds of science that's being done, and my most favorite part is this little visual here that we're gonna spend some time looking at, but it does a really awesome job of talking through how the process of science is rarely linear and it's often sort of creative and exciting, which depending on your exposure to science, that may not be your experience with a process of science. So before we begin, let's go ahead and do some definitions. I'm gonna write down some definitions. This whole lecture is going to be, I find this stuff difficult to organize because there's a lot of information and there's a lot of, well this is true and this isn't true and what about this and how do you think about this one? This list of definitions is a bunch of definitions that are commonly, they're differently used in science than they are maybe in common language or in the media or every day. So I am a little bit sad to write this first one down for you because I, well when I write it down for you, you will see perhaps why I'm sad. I'm a little sad that we have to spend some time defining the word fact because it's one of those that like I would not have thought that the word fact was debatable but it is and so I'm gonna give you a definition that's just gonna guide our, like the way we use words in this class. A fact is a statement we know to be true through direct observation. The next definitions that we're gonna look at, bit better. I'm gonna give you the next one. I'm not done with fact but I'm gonna give you the next one. The next one is theory and this I think hopefully will help you see why I included fact in this list of definitions. In science a theory is a broad explanation. I'm gonna write that down. A broad explanation that's usually supported by many lines of evidence supported by many lines of evidence. Okay, I hope this handwriting is okay for you. Theory is a word that we've always had a difference in the way we use the word in science compared to the way we use the word every day and commonly. When I say I have a theory when I'm hanging out at the dinner table I'm saying this is my random idea and a theory doesn't always carry a lot of weight in our common use of the word. In science a theory is as close as you can get to something that's really really really really true. As we will learn science is a process that gives us information but it's always changing. A theory has so much evidence that is supporting it that it carries a tremendous amount of weight. You can hear the difference in how we use the word theory commonly and how we use the word theory in science. It's disappointing to me that there is a difference in how the word fact may be used commonly. That's new. With the advent of alternative facts I want to be very very clear that in this class that like there really aren't alternative facts. There are things we know are true based on direct observation and that's how we're going to use the word. Just like in this class when we talk about a theory we're going to talk about a broad explanation supported by many lines of evidence. The other word there's a couple more here that have different uses hypothesis. We're going to talk about this word a lot and so we'll have we'll have more words to say about hypothesis but I'm going to give you a definition now. A hypothesis commonly is similar to theory it's like a guess commonly. Not how we use it in science. In science it is a proposed explanation so think about that. Proposed I think I spelled that wrong. A proposed explanation for to explain a narrow set of observations so it's really specific it's kind of narrow and there are some things that are true. It's a proposed explanation that is testable so you have to be able to design some kind of test to check it and it's falsifiable and this we're gonna again we're gonna talk about this a little bit more but I just want to throw it at you. That means that you can provide evidence that your hypothesis is not true. You know what you're looking for that will tell you that oh that is not true and it has explanatory power. It tells you something about what you already know and has explanatory power. So hypothesis is a really specific type of thing that we build or we generate in the sciences. Okay I have two more for you. The next one I have is law and this is another one where you're gonna see laws used in science they usually are generalizations based on a lot of data so they carry explanatory power or predictive power but they are less clear than like a theory. A theory if something's labeled a theory you know there are many many many lines of evidence from lots of different areas that support this idea. A law is used a little more muscially in science. I want it out there we're gonna see some laws you may wonder why is this a law and not a theory we can have that conversation when it comes up. The last one I want to address is the scientific method and I want to address this because this is most of y'all have experienced science through the lens of the scientific method and it's basically a recipe for doing science. It's very linear when I say recipe I'm like that's exactly what it is. I always I hate to admit this as a science human I always kind of didn't love science labs because they felt like recipes for doing a thing it wasn't discovery it wasn't question asking it was following a recipe and the scientific method to me is not super inspiring whereas the process of science is super inspiring and interesting. In the next lecture let's look at the process of science and sort of the next section we'll look at the process of science and how it is different than the scientific method.


Welcome to everybody. Today, I'll be talking about working length determination. I'll be talking about this particular topic. And the following contents. I'll begin with introduction. I will go on with the definitions involved in working length. Anatomy of the root apex clinical significance of working land different methods of working in determination and the most common methods in our clinical practice. In radiograph, like such as radiographic and non radiographic methods. Let us begin with introduction. One of the main concerns in root canal treatment is to determine how far the instrument should be advanced within the root canal. And at what point preparation and filling should terminate. Winning shaping and obturation cannot be accomplished unless working length is determined precisely. Next coming on to the most common definitions to understand working length concept. Working length is defined as the distance from the coronal reference point to a point at which canal preparation and obturation should terminate. The reference point, it is a site on occlusion or incisal surface from which measurements are made. This point is used throughout canal preparation and obturation. Anatomic apex is defined as a tip or end of the root determine morphologically and the radiographic apex is defined as a tip or end of the root determine radiographically. Next coming on to the major and minor diameter. Now major diameter or apical foramen. It is the main apical opening of the root canal. It is frequently essentially located away from the anatomic or radiographic apex. Now, can you see how this is the major apical diameter. Now coming on to the apical construction or a minor diameter. It is it is the apical portion of the root canal having the narrowest dimension. Now, can you see this particular figure? Now, this is the apical construction or a minor diameter. Now, next is a cemento-dental junction. It is a region where the cement and dentine are united. Now, to understand the cemento-dental junction, as we all know, there's a dentine in the root canal. Now, this dentine means the cement of the root apex and that location where they both unite is called the cemento-dental junction. Next, we will understand the anatomy of the apex. Now, this understanding or this knowledge is very important to understand the concept of working length. So, if understood properly, we can establish an accurate working length. So, to understand this particular anatomy of the root apex, we need to know certain components of this root apex. Now, the root apex generally comprises of apical foramen, apical constriction, cemento-dental junction, lateral canals. Then there is a canal curvature and there are different types of root apex. So, I'll be talking about all this under the following slides. Let me begin with the apical foramen. Apical foramen is rounded edge like a funnel or a crater that differentiates the termination of the cemento-dental canal from the exterior surface of the root. So, this is the apical foramen. Okay, foramen is nothing but an opening. As we know, in astrology, we all have heard about the various foramans in our skull. So, to understand it better, it's just an opening of the root towards the apex. Now, the location and shape of fully formed apical foramen vary in each tooth and in the same tooth at different periods of life. Next, coming to the apical constriction. Now, apical constriction is the narrowest part of the root canal with the smallest diameter of blood supply. As you can see here in this particular figure, it's the narrowest part of the root canal system. Now, preparation to this point results in a small wound site and optimal healing conditions, means to say that if you try to prepare your canal like a biomechanical preparation, or if you try to operate the root canal to this point, it can create an optimal healing condition. Now, apical foramen is not always the most constricted part of the root canal. From the apical constriction, the canal widens as it approaches the apical foramen. Now, if you can see here, it widens when it approaches the apical foramen. Now, this shape can be compared to a funnel shape or it can be compared to a hyperbolic shape or the shape of the morning glory flower. Next, the important landmark in the root anatomy is the cementodentinal junction. I've already explained about the cementodentinal junction as to what it means. So, it basically means the dentin meeting the cement of the root apax. Now, it is a histological landmark. It cannot be located clinically or radiographically because it is present in the canal system. So, we cannot really determine it morphologically or clinically. Next, coming to the various lateral canals or accessory canals present in the main root canal. The knowledge of lateral canals is very important to determine the working length precisely. So, we need to know the exit, the origin of the lateral canals. So, a lateral canal is located at right angles to the main root canal. You can see here it is the lateral canal originates at right angles to the main root canal. Now, accessory canal. Now, here is the accessory canal. It branches off from the main root canal in the apical region and the forkation canal originates in the forkation area. Now, these canals are areas for interchange of metabolic and breakdown products between the pulp and the periodontal tissue. So, if any disruption of this area or if any infection results in the pulp, which it can reach the periodontal tissue, also the vice versa, if the infection is existing in periodontal tissue, it can reach the pulp. Now, we need to know two important canals, which is lateral canal and an apical delta. Now, if you can see in this particular radiograph, this is nothing but a lateral canal, which is right angle direction from the main root canal. Now, where is the apical delta can be seen in the root apex? So, this is a branching pattern of small accessory canals, which can be seen at the tip or apex of the sum two. Now, in this particular radiograph, you can see a mandibular molar showing in apical delta. So, sometimes this apical delta is very critical to obture it because sometimes if any irritants or bacterial byproducts are there in this particular apical delta, chances of reinfection or it can, you know, the obturation, it really determines the success rate of the root canal treatment. Next, moving on to the significance of working and determination. It determines how far into the canal the instruments are placed and well and thus how deeply the tissues, the debris and metabolites are removed. It limits the depth to which the canal filling may be placed. It affects the degree of pain and discomfort that the patient will feel following the appointment. If calculated within correct limits, it will play an important role in determining the success of the treatment and conversely, if calculated incorrectly, may cause the treatment to fail. Next, coming on to failure to accurately determine and maintain the working length. Now, what are the main causes of failure? Suppose the length too long. Now, suppose if you have calculated working length and the length of the working length is too long can lead to perspiration through apical constriction. It can lead to overfilling or overextension of the gutter pressure points. It can lead to increased incidence of postoperative pain. It can lead to a prolonged healing period and low success rate owing to incomplete regeneration of cementum, baritone ligament and alveolar bone. Now, problems associated with the shorter working length. It can lead to incomplete cleaning that is incomplete debridement of the bacteria and its byproducts from the main root canal. It can cause underfilling of the root canal. It can cause a persistent discomfort to the patient. It can cause incomplete apical seal, apical leakage, which supports the existence of viable bacteria and contributes to a periratical and lesion. And also the main factor or main point to be noted here if the short working length is present in root canal treatment, it can lead to a lower success rate. Now, how to measure working length? Now, measurement should be made from a secure reference point on the ground that can be identified and monitored accurately in close proximity to the straight line path of the instrument. Now, reference points in anterior teeth are usually the incisal edges and in posterior they are the cusp tips. The reference point must be definite and reliable point or surface to ensure exactness in all subsequent measurements. Means the reference point should not be changed in but in following appointments. So it should be a reliable point. Now incisal edges or cusp that are undermined or fractured should be ground until a sound surface is attained. So the statement means if suppose there is uneven surface or there is a up and downs in particular incisal edges or a cusp tip. So it should be made flattened so that that particular point can be used also in the next upcoming appointments. The reference point is the site on the occlusion or incisal surface from which measurements are made. A reference point is chosen that is stable and easily visualized during the preparation. Reference point that will not change during or between appointments is selected. Do not use weakened enamel or diagonal lines or fractured as a reference site for length of tooth measurement. Weakened cusp or incisal edges are reduced to a well supported tooth structure. You can see here there is a fractured anterior tooth which has made stabilized to which has made even so that a proper attainable reference point is achieved. So this reference point will not be changed in subsequent steps of the root canal treatment. Next moving on to the different methods of working-line determination. Now there are basically two different types of working-line determination. One which involves a radiograph and one which does not involve the radiograph. Now radiographic methods can be different types. Now there are so many types which are mentioned here. Starting with best method, Brickmans, Bramante's, Grossman's formula, Engels method, Wien's method, Cutler's method, radiographic grid, Euclidean endometry, zero radiography, direct digital radiography, subtraction radiography and endometric probe. Now the most common used radiographic methods in our clinical practice will be either Grossman's formula, Engels method and Wien's method. Whereas non-neutographical methods are becoming more popular as in the current era of practicing endodontics which can be digital tactile sense, apical periodontal sensitivity, electronic apex locator and paper point method. So in this the electronic apex locator with the different generations of apex locator available, it is becoming easier for us to accurately determine the working-lines. Now let us understand the most commonly used radiographic methods first and then we will move on to non-neutographical methods. Now this is the basic idea of radiographic method of determination of working length. Now in this particular slide you can understand there is a radiograph which will be exposed. That is that preoperative radiograph will be exposed and then files will be placed in the root canal and then one more radiograph will be exposed and with the addition or subtraction principle we can accurately determine the working length. Now there are two techniques of radiography which is involved in assess our determination of working length. The first technique is paralleling technique and the next technique is bisecting angle technique. Now I am not going to the oral medicine aspect or oral radiology aspect to give you the insights about the both techniques. So whichever technique is feasible to our practice or wherever you are practicing or you want to calculate the working length you can choose either of the technique. Now coming to the Grossman's method. In Grossman's method it involves a series of radiographs which can be a preoperative radiograph and placing the file inside the canal and taking a radiograph later on. So the correct length of the tooth can be determined by the Grossman's formula. It can be calculated by correct length of the tooth is equal to known length of the instrument in the tooth into apparent length of the tooth on the radiograph. That is after exposing the radiograph while placing the file on the root canal divided by apparent length of the instrument on the radiograph. So with this formula you can calculate the working length of the tooth. The next which is the most commonly used in our clinics is Ingle's method. Now this method is very simple like first we have to measure the tooth on the preoperative radiograph. So this is the first step wherein you measure the tooth length in the preoperative radiograph. Then you subtract 1 mm as a safety allowance for possible image distortion or magnification and then you place the file. Now suppose this particular length of the tooth is 23 mm. Now we have subtracted 1 mm and we adjust the length to be 22 mm and with this file the endodontic file is placed in the root canal and one more radiograph is exposed. Now another radiograph on the other radiograph measure the difference between the end of the instrument and end of the root end and add this amount to the original measured length. Now suppose if the instrument is at the apex there will be no need to change the root canal length. If suppose there is a difference in the length. Like suppose if you find that there is a 1 mm short of the length you can adjust it according to the preoperative radiograph. If the instrument has gone beyond the apex, subtract this difference from the adjusted length of the tooth and subtract 1 mm. Now safety factor to confirm with the apical termination of the root canal at the apical constriction. Now the safety factor is nothing but you have to subtract 1 mm from the actual length of the tooth. That is only because that major and minor diameter are always separated by a distance of 0.5 to 1 mm.  Now suppose you calculate the working length in the radiograph and it is 23 mm. So for the safety factor you need to subtract 1 mm and you need to keep your working length as 22 mm. Okay that is about the Engels method of working length determination. Now for this, Veen has given some modifications in a length subtraction. Now he says that if there is no resorption in the first picture you can see if there is no resorption, if there is an optimal periapical condition, you can subtract 1 mm. And suppose if there is any periapical bone loss present you can subtract 1.5 mm and if there is any periapical bone loss with root apex resorption you can subtract 2 mm. So these are the Veen's modification which is very very very important for us to know wherein in those particular three conditions to subtract how much length from the main calculated working length. Now according to Cutler what he has told is like anatomy of the root apex he has divided or he has given some facts about the distance between the major minor diameter, the apex of the tooth and the minor diameter. So the main point to be remembered here is the distance between the major and minor diameter is 0.5 mm in 18 to 25 year old and 0.7 mm in 55 years or above. Okay and the distance between 1 and 3 that is the apex and the minor constriction is in the range of 0.1 to 2.7 mm. Okay so it can be from very minimal to maximum of 2.7 mm. Now coming to the advantages and disadvantages of this radiographic method. The advantages of being you can see the anatomy of the tooth. You can see if any curvatures of the tooth roots present if present it can see a relationship between adjacent teeth and anatomic structures. Disadvantages being it varies with different observers it can superimpose the anatomical structures. It can give a 2D view of a 3D object and it leads to a radiation exposure. It cannot interpret if apical foramen has buccal or lingual exit and also it has limited accuracy. So with all this disadvantages kept in mind the researchers have gone from radiographic to non-radiographic. So now we will see the most commonly used methods in our critical practice which involves no radiography. The first one is digital tactile sense. Now this method is very simple method wherein with the digital tactile sensation we can feel the apex of the root. Okay you can just take a file and you can just feel the apex of the root and also to keep in mind this comes with experience. Suppose if you have an experience you can really feel the root apex. So you can try it out in the extracted tooth models and then you can try it out on the patient. So advantages being for this method it is a time saving and there is no radiation exposure but also there are some disadvantages. Suppose in cases of a narrow canals one may feel increased resistance as the file approaches the apex. Also in cases of teeth with immature apex the instrument can go very apically 2 to 3 mm beyond. In case of anatomical variations in apical constriction or sclerosis or resorption and age this method becomes unreliable. So this method should be considered supplementary to high quality carefully aligned parallel working length radiograph or an apex locator. So this is a supplemental method. Next is the Paradontal Sensitivity Test. This method does not provide accurate readings for example in case of narrow canals instrument may feel increased resistance in apical 2 to 3 mm. Now this Paradontal Sensitivity Test is mainly a test wherein you can get the patient's response of pain. Suppose when you put a file inside the tooth now you can proceed or you can advance your file to a point wherein patients ask you to stop it because it will be very painful for him to experience that particular you know the situation. So this also can be used as a supplemental method in working length determination. Next is the Paperpoint Measurement Method. This method however may give unreliable data. If the bulk is not completely removed like suppose this is nothing but using a paper point and we can place it in the canal. So you can advance this paper point to a point wherein you can see a bleeding or suppose in the apex of the root canal when there is a bleeding point it makes the working length determine accurately. Suppose I can give you an example that suppose in a patient wherein you have extirpated the bulb correctly you can place this paper point and this paper point when it reaches the apex there is a bleeding point noted. So that is how we measure the working length in this particular method. But this method cannot be reliable if suppose the tooth is pulplis and a periobacterial lesion rich in blood supply is given because if such thing is there the entire paper point will become red in colour. Also if the paper point is left in canal for a long time it gives you an unreliable result. Next coming on to the Electronic Apex Locator. In addition to radiography tactile sensation has been used with questionable success. The drawbacks cited about radiographic length determination, the introduction and development of apex locators was received with enthusiasm. This device does not assess the position of the root apex and the name electronic apex locator is not appropriate. Electronic apical foramen locator or electronic root canal length measurement device as a generic name would be more appropriate. So it is basically electronic device which can be used to determine the apical foramen or minor constriction using electric current. So we will understand the mechanism of how it accurately determines the root length. It uses the human body to complete an electrical circuit. One side of the circuitry is connected to an endodontic instrument that is here. If you can see one side is connected to an endodontic instrument and the other side to the patient's body. So this is the other side which is a lip or a chin or a buccal mucosa here and is connected to the patient's body. The patient's lip or by an electrode held in the patient's hand. You can also make patients hold it or keep it in its hand. The functionality is based on the fact that the electrical conductivity of tissue surrounding the apex of the root is greater than the conductivity inside the root canal system provided the canal is dry. Now the length of this is measured by the electrical difference between the canal, the canal conductivity of the current in the canal and also in the pellet apex. So differences in this both situation will lead to a determination of a point wherein you can look at the minor constriction. The parts of the apex locator. Now it has four parts. It is the lip clip, the file clip, the electronic device and the cord which connects above three parts. Coming to the uses of the apex locator, it provides objective information with high degree of accuracy. If there are suppose any overlapping routes in cases of mandibular or maxillary molars, it can determine the working length. If there is an excessive bone density present in the apical portion of the root, it can determine the working length. It can be used in patients with gag reflex and cannot tolerate x-ray films. It can be used in pregnant ladies to reduce the radiation exposure. It can be useful in children, disabled patients, heavily sedated patients, etc. So these are the basic uses of the apex locator. The conditions for the accuracy of electronic apex locator can be like basic conditions to for accurately it has to be present to accurate for the accuracy of this particular apex locator. The canal should be relatively dry. The canal should be free from debris. There should be no cervical release. There should be no blockage or calcification of canals. There should be proper contact of file with the canal walls and the periapics. These are the basic conditions required. Coming to the different generations of electronic apex locator with some of the examples. Now coming to the first generation, it was mainly the main principle involved and its working was resistance. So it used to determine the resistance between the flow of the current in the apex and the canal system. So the examples were endometer as the dendometer, then also there is a cofinken by Denmark company. Next was second generation was impedance. Now impedance, the principle involved here is impedance, which was used and the examples being the Sono Explorer and Digipex 2. Whereas the third generation is the frequency, which is most commonly used in our clinical practice. It gives you different frequencies in the root canal and also in the apex. So the most common example for this can be the ND 5000. Also the index are up to the apex locator. The next thing the fourth generation apex locator, it has dual frequencies which are involved to accurately determine the working length. It can be root ZX and propex to fifth generation. It involves the multiple frequencies and it is one of the recent advanced type of an apex locator, which determines the root apex 90 with 99.9% accuracy. And the last being the sixth generation or an active type of apex locator. So this is still under the research stage, but soon the days are not far that we can get a apex locator which can accurately determine and which can replace the radiographic method. Finally the conclusion the minor diameter is a practical and anatomy termination point for the preparation and obturation of the root canal and this cannot be determined radiographically. Modern apex locators can determine this position with accuracies greater than 90% but with some limitations. No individual method is truly satisfactory in determining endodontic working length. Therefore the combination of the methods should be used to assess the accurate working length determination. So that's all about the walking and determination. I thank all of you to attending or listening to this lecture. Thank you.


What if CPD was not only engaging, but it made a difference to your classroom friends? Okay, schools continue with the lockdown, what can I do to help you?  Whether you're putting the kids to bed or whether you've put the kids to bed already and you're on the sofa with a glass of wine, I've been thinking about how I can continue to share best practice in this current circumstance where I can't come out to schools. You have probably got an increased workload, a growing kind of anxiety, sleep, or need some motivation, whatever it is. Having a little think about some of the resources on my site, most popular, some that are kind of locked down behind the scenes and some of the resources that I know make a difference. Throughout the pandemic, I've also been working with a huge number of skills and that's also determined my own workload. I'm thinking about how I can support you as an individual teacher outside of your school circumstances. So following the research on memory, what can I give teachers where there's no frills? Give the video, watch it live or recorded. You get all the slides, you even edit the templates. It doesn't give you any additional workload. And what content has made a big difference? What I know about memory, effective feedback, marking and behavior, curriculum thinking, lesson planning, kickstarting your own research journey as you move into an academic world. Maybe it's how to write a book, how to write a blog, how to create your own social media channels. So whatever it is, I'm listening to many resources that I know be of good value. I also know it's going to make a difference. At the end of every session, there's an opportunity for you to stay on the line and have a one-to-one. Whatever it is, I'll be there to try and give you the support that I think you need at this challenging time. So what you're waiting for, sign up. I hope to see you there.


Welcome to the Everton News Daily. Ella Sims is in talks with Coventry City about leaving Everton on a permanent basis to join the Sky Blues. He is due at Coventry today for a medical according to reports. A project of fee of around between £6-8 million has been mooted for the 22-year-old who scored once in the Premier League last season for Everton. A crucial equaliser in a two-all draw at Chelsea. It hasn't worked out for Sims at Everton and that's your own date has made the decision to allow him to leave. I think if we have to just accept where we are right now, if this is a player that isn't going to be part of the manager's plans, then we may as well go and get a fee for him and hopefully it will help us in what we need to do. There's no point in keeping plays around the squad that aren't going to play. For Sims himself, everything's been a little bit of a stop-star for him over the last few years. He's had low moves to Blackpool, up to Scotland at heart, off to Sunderland for the first part of last season which he did very well in and then was called back to Gooderson Park for the remainder of the season. This will be an opportunity for him to put some roots down and become the main striker for the team. We wish Ellis well if he does Cy for Coventry over the weekend. Everton are reportedly interested in Geng's sensation, Christopher Bonsu Bar. Now the interest this is coming out of Belgium media today. He's just signed for Geng last week and therefore I don't really understand this link. I think I understand Everton keeping an eye on him. He is really highly rated 18 years of age, bright and very interested in him. In fact they try to hide his deal before he got a Geng. But Belgium media saying Everton are about to submit a bid for him, I think is nonsense in all fairness. We are just here to report the news and this is in the news today so we are reporting it. But I do not see this one happening. Certainly not this summer when he just arrived in Belgium last week unless they are just literally bringing him into Salomon. We'll see. But Everton do remain interested in bringing lead striker Roderigo to Gooderson Park. Some reports suggest that that deal could actually even be done over the weekend in time for Everton's trip to Switzerland. The player has indicated he wants to leave Ellen Road. A fee of around £3-4 million has been put out for the 32-year-old striker who got 13 goals last season for Leeds United as they were relegated to the championship. This is something that has been around now for about 7-10 days ever and very interested in bringing him in. He won't be the only forward that this and Everton are after but it will be a decent start to it near a fee like that. I understand and as someone who continually goes on about selling on value and things like that for players and bringing in younger players and developing them, this is a little bit of a different angle from that but it's someone who's got that experience can also play just off the striking and can play in a wide area as well. You can understand why he appeals to Sean Dyche and Kevin Thelwell right now. Another player Everton that's still very interested in, according to Italian media, is Wilfred Nonto, also of Leeds United. Last and Villa, apparently interested in them as well into my land. I've looked as well but the Italian press certainly think Everton are in the driving seat to take the 19-year-old to Gooderson Park. A favour around £13 million has been mooted for this player again. This one is a player, I think a lot of Evertonians like to look off. Given his age he's obviously got a big ceiling. He's lively, he's got two goals and four assists last season for Leeds United. I've got four goals in all competitions I think as well so we'll see whether there is anything in that one but Everton certainly trying to do some business in their attack and third. It's where they need it most. Obviously the sale assumes if that goes through coming off the back of issue Samuel Smith to Chelsea as well so some money coming into Gooderson Park which might enable Everton to begin moving in the other direction and bringing players in. Finally Everton Academy player Isaac Heath has signed a two-year professional contract. It's his first professional contract and Heath wants to continue developing at Gooderson. He said the dream come true to sign a professional contract once you now kick on and develop under the stewardship of Leighton Beins and Paul Tate and the Everton Academy level. That is it for the news day. Give the video a thumbs up and subscribe if you haven't. Have a great weekend. See you later.