Tuesday, January 26, 2010
The University of Colorado School of Dentistry entrance exams will be coming up before you know it! Last year they were on May 2 and May 9, and it will be similar this year. These are the first practical exams for 2010, and there is still time to prepare - but that also means that there is time to do a comprehensive preparation.
This is a good time to take our Online FRT (Fundamentals of Restorative Techniques) program, which is designed to help you prepare for practical examinations.
Check out our dentistCEprogram.com website for a complete description, even including homework assignments that you do at home and send to me so I can evaluate your preparations onto a DVD.
If you can get here, we have 18 day courses early in the year, since people aren't in so much of a last-minute rush, and 9-day programs for those who can't stay out here quite as long. But if you cannot come out even that long - it is highly recommended to take the much less costly online program. If you have done a comprehensive job with the online program - you can even come out for a three-day hands-on, real-time, one-on-one with me to really make sure that you are doing things in the most effective way and safe way - and I will show you how to work more quickly and still get excellent work done.
We offer many ways that you can learn what you need to.
Please don't wait until you get an invitation to a school interview before starting to prepare! First of all, you won't have time to learn what you need to. And, taking the course earlier will definitely help you get the invitation!
February, March and April can be big months for your preparation for these exams - and making sure you know how to do many preparations with precision and confidence, based on a sound knowledge of all principles.
Monday, December 7, 2009
There is always confusion about how clinical examinations are graded. You do a class II amalgam preparation on a patient, for example, and think you have made very few errors and fail, or make many errors and pass, or make a serious error and pass.
We certainly emphasize these issues during our courses - but a lot has to do with the examination itself. There are two distinct ways to grade a clinical procedure - we will call them the "critical error" approach, and the "average error" approach. In the former, the overall grade is given according to the worst thing you did, and in the latter the overall grade is determined by summing the grades in a number of sub-categories, essentially averaging the errors.
I won't here go into the details of deciding between slight and moderate errors, but whether an error is important enough to be considered failing is important.
Let's say you over extend the facial proximal wall AND you underextend the pulpal depth. For the amalgam procedure, if the thickness of amalgam in the isthmus would be inadequate then the lifetime of the restoration is compromised and that is a major, or failing, error. If the facial wall is overextended by .5 mm or so, and the lifetime would not be impacted, then this would be a moderate or still passing error. For some exams the overall grade for the preparation would be failing because there is one major error, but for other exams only the part of the grade associated with internal form is failed, but the outline form category still passes. Overall the preparation could actually pass if other categories had no errors!
We would like to pass the exam, so the "average error" method sounds desirable - but how does Nature grade? In other words, will the preparation pass LIFE? It doesn't really matter how board examiners grade the preparation - what matters is how it will serve the patient. It would be nice if there would be some correspondence. Unfortunately, in the "average error" case there is not - the preparation can pass the exam but the restoration may break and fall out within days. In the "critical error" grading, the preparation will fail the human graders and fail as well in the test of life!
For the now-discontinued California Dental Board Exam - the old Cal Board - the grading was always based on the critical error. The passing rate was somewhat lower than for other exams based on the average error, but the mandate to do better work was paramount.
Interestingly, it is still possible to pass the some board class II procedures even if you damage the adjacent tooth so severely that the pulp is exposed!
Let's work toward having NO errors that are severe enough to compromise the lifetime of the restoration, and then we will deserve to pass our clinical exam and get fairly licensed.
Monday, November 30, 2009
Since the season for clinical licensure exams is starting to come back around again - I thought I would make some comments about patient selection, or lack of selection, as the case may be.
It is important, or critical, to realize that for patient-based exams the choosing of the appropriate patient is much of the exam - you essentially create your own exam. This is reasonable, since the examiners are really checking to see how much dentistry you understand, and the ability to tell what to expect from a certain tooth in a patient is an important clinical skill. In other words, they are grading you on JUDGMENT - and we hope you have good judgment and exercise it, but you must realize also that this can't happen unless you collect data from which you must make that judgment. Many people fall down in the data collection part.
That being said - you are graded largely on your ability to determine that a particular patient case is within your skill range - but what if someone else chooses a patient for you?
If you have someone else choose a patient for you - for example if you get a patient from a patient-finding service - you may not see inside the patient's mouth until the start of the exam. This means that someone else is creating your exam for you! Definitely not the way to go....
There are people that would like to do away with patient-based clinical exams for licensure, and just have typodont and theoretical exercises instead. My main argument against these people is that I have seen thousands of dentists and dental students learn a lot more dentistry as they go through the process of getting ready for a clinical exam, and this would be lost. These examinations are not about how much you know now, but how much you can learn before the exam. Very few U.S. dental school graduates are ready to practice dentistry upon being graduated - but most will reestablish their landmarks and standards and ability to evaluate subtleties in patients as they prepare for these exams - and this takes them toward a more independent patient interaction and understanding.
If clinical exams for licensure in the U.S. were run by their providing you with a patient and asking you to do a certain procedure, you can bet that the hew and cry would be stentorious objecting to this exam format. And yet, if you pay someone to find a patient for you, often this is exactly what you are subjecting yourself to.
But even under these circumstances, your skills at looking at a tooth and deciding what needs to be done and what to watch out for while doing the preparation and restoration, and what are the dangerous aspects of each case, will be paramount in determining your success.
Over the last 10 years we have recorded thousands of patient evaluations involving discussion of prospective patient cases and working through what to expect from each - would they be a reasonable board case or not - would they be an acceptable board case or not.
Now a selected set of these evaluations is available for you ONLINE. Check out dentistCEprogram.com for information about our offering!
Whether you are looking for patients yourself, or using one provided by someone else, you need to know that you are looking at and how it will relate to your skill level. Most people looking at a maxillary first premolar DO don't notice several common situations that can make their lives very miserable indeed. Learn to look, learn to see - only this gives you the opportunity to use good judgment!
Monday, November 23, 2009
For those who are taking Advanced Standing Entrance (practical) exams, during the on campus interviews, it is going to be a really good idea for you to be aware of what it takes to get a typodont in shape. That means that the proximal contacts are there and passive and the occlusion is reasonable and stable. I discussed in another post the difference between Columbia and Kilgore tpodonts, but didn't really get into how to make each of them good enough for an exam.
While the practical exams are mostly over for this year, the first one for 2010 will probably be in May - at least the Colorado exam was in early May this year, and this comes pretty fast. Those who didn't apply during this season or who are planning to apply next year, should start figuring out some of the issues right away - and one is control of the typodont.
In the next few months I will make a new videotape of typodont equilibration and put it on our DDSeClass.com website, so you can sign up and see how it is done. But there is no definite rule, except the same one that works in the patient's mouth - figure out what the problems are and then invent something that will fix them!
There is, however, a reasonably systematic approach to adjusting a typodont. I will go through some of it here and leave the rest of the details for the eClass. First, I will point out that the other day I equilibrated a student's typodont for the USC exam, and it was really a mess. The typodont was Columbia and only about 2-3 years old, but the teeth I have, which are newly manufactured, did not fit well at all. The problem is that when you put the teeth into the socket and look through the hole in the bottom of the typodont base, the screw hole in the tooth doesn't line up. In this instance the hole in the base must be enlarged so the screw will enter the tooth passively and not break the tooth.
Provided the holes all line up, we need first to tighten all of the screws on the typodont, so that if they are tightened later during equilibration, nothing changes. Also it will prevent rotation, which is a big problem on the anterior teeth. Then I will take out all of the second premolars and the maxillary lateral incisors. At this point I check to see how passive the contact is between the molars in all four quadrants. I also check to see how the contacts are anterior to the removed teeth. Also we need to know if there is room to put the second premolar back in the socket. Sometimes there is more than enough room, and sometimes, like the newer Columbia typodonts, there is not enough room. Then we have to decide which way to move the teeth anterior and posterior to the missing tooth so that there is just the right amount of space to return the premolar, and so that there are good contacts in the anterior and posterior regions, and they are passive contacts.
Sometimes a lot of tilting of the teeth is involved. Sometimes all of the proximal contacts in the anterior and posterior segments are fine, but there is not enough room to return the second premolar. In this case, the second premolar is usually recontoured to fit the space that is available.
I will describe here some techniques for tilting teeth, but I will save the occlusal adjustment for another posting.
If you wish to tilt a premolar mesially or distally, it is usually possible to cut the bottom of the tooth at an angle, so when the screw is tightened, the tooth will tilt accordingly. Sometimes the tooth won't tile because the head of the screw sits on the base in a bad way, so we recut the surface of the base where the head tightens at an angle. For molars it is generally best to take a small piece of aluminum foil (I generally use a strip from the edge of a scalpel blade package) and place it under the tooth, on one side or another. You can also use foil to raise a tooth into occlusion, or to raise AND tilt a tooth at the same time, by using different thicknesses of foil in two different locations. The scalpel foil can be folded a number of times to get different thicknesses. Sometimes I've had to use 5 layers on one side of a tooth and 7 layers on another to get it raised into occlusion, but without the facial cusp (say) too close to the opposing tooth surface.
When we get back into prime practical exam preparation "season" we'll be going over more of these things more carefully and I'll be answering more questions.
It is also relevant that typodont equilibration is important in some Regional Clinical Licensure Examinations, like the CRDTS, but a lot of people don't realize it due to the way the exam is graded.
Monday, November 16, 2009
Just a few notes here with respect to the Kilgore versus the Columbia typodonts. Depending on which school you apply to, the practical exam at the interview could involve one or the other, and either could be on a manikin or hand-held. The USC exam that was just held yesterday involved hand-held typodonts - which is actually more complicated for some procedures and a lot less realistic, of course. But if you can do the preparations well in the manikin, you know exactly what to look for as you do the work hand-held - just practice a little.
BUT, the Kilgore and Columbia typodonts are significantly different in several important ways. The nature of the ideal preparations, of course, does not change, but the sensitivity of each typodont to any overextension or carelessness in margin placement is very different.
Mostly, we are looking at Kilgore typodonts for the Northern California schools, but there are others as well. Be sure to ask what typodont they are expecting you to use, and if you supply your own or not. Remember that ALL typodonts have problems with positioning of teeth so that there is good proximal contact, or at least some, and it is not ACTIVE, and that there is good occlusion, with solid vertical stops for posterior preparations.
But you must be aware that for the Kilgore typodont the proximal contacts are positioned much farther toward the facial than for Columbia, and the occlusogingival width of the contact is very small, typically, for the Kilgore. This means that the box for a class II is shifted to the facial with respect to the isthmus, and that very little gingival extension is required to get gingival clearance. In fact, if you are not careful about your pulpal depth, you may have gingival clearance before even making the box!
For the Kilgore, it is generally easier to cut a crown preparation through the proximal contact area without coming too near the adjacent tooth, because the gingival embrasures are so large, but the preparations tend to be shorter than for Columbia, because of the smaller clinical crown. This makes over reduction of the marginal ridges a more serious problem, due to the short resultant walls and limited retention.
For the Columbia, active proximal contacts is a continuing problem - necessitating adjustment of the bottom of the tooth at an angle, recutting the seat of the screw on the back of the base, or placing aluminum foil under one side or the other of the bottom of the tooth, mostly molars in this case. If the adjacent tooth shifts while cutting a class II box, it can cause real problems. To say nothing of the very large contacts occlusogingivally for Columbia, often requiring very deep boxes to get gingival clearance. The newer Columbia typodonts use a different plastic for the base than they used to - exchanging Melamine for, I think, Nylon. This new base does not lend itself well to the adjustments that are necessary to get teeth to fit with only passive proximal contact.
A few days ago I equilibrated an older typodont - only 2 years old - and had to replace most of the teeth with new ones. Normally this would cause difficulties, having to adjust ALL proximal contacts in a sequential fashion, but in this case it was doubly complex, because almost all of the teeth did not fit the screw holes in the base. That is, when you look at the bottom of the tooth through the screw hole in the base, the hole in the tooth is not centered, often points so that the screw will hit the side of the hole in the base (hence tipping the tooth), or the screw will not even go into the tooth. In this case I had to recut the holes in the base in all of these cases - if that were not done and the screw could be tightened into the tooth, the tooth would almost always break. Some of you might have had this problem before - but it is becoming more frequent with Columbia typodonts recently!
If you read this post and find the subject of typodont equilibration important for you now or in the future, with a little encouragement I will make a videotape of the procedure for a couple of typodonts so that you can see some of the techniques that are necessary. Realistically, most students that see how complex this can be, elect to have me do it for them if they are to take their own typodont to an exam. If you use a typodont supplied to you by the school, know at least enough to check it and see if it will make your life more complicated because they did not equilibrate it well enough!
Tuesday, November 3, 2009
Some comments should well be made about composite preparations as they may be found on entrance exams - so far I only know of one that gives the class III and that is U Mich - see another posting. For the USC exam it could well be that the case descriptions that they give you would call for either a composite or amalgam class II filling, and you should know what the criteria are for either. But you should also know how to do them. There are some significant issues that one comes across with these preparations, and, it must be known, that not all examination entities agree on the ideal preparation designs.
For example, the class III composite preparation. Know, first of all, that if you are preparing a typodont tooth, you must have a clear picture of where the decay WOULD be. It's pretty much the same as for a class II, the decay is at the gingival portion of the contact area, but here we enter from a completely different direction. Now there is some question about how much of the contact needs to be involved. In reality, typically, very little of the contact is involved. The incisal margin is generally in contact with the adjacent tooth, but it is not placed too far into the contact - if it is IN contact, that is far enough incisally.
The facial extension is another issue - both for clinical exams and manikin exams. For the patients it is easy to see how far the facial margin will have to be extended, because the surface decalcification is generally found into the facial embrasure, at least far enough so that the facial clearance will allow a bevel to remove the last of it. For a typodont, various approaches may be mandated as to how far the facial margin is extended - there could be the directions "don't break facial contact" - which tells you exactly nothing. Generally, I council my students to extend the facial wall, angled outward, until there is just enough clearance facially so that a facial bevel can be placed all the way to the incisal wall. This most closely duplicates what we commonly find in patients.
Should there be a bevel on the class III margins? All the textbooks say yes. Regional clinical board exams, even for patient-based procedures, generally state that bevels are optional! What does this mean? It really means that you need to decide whether to place a bevel or not. I can picture situations where, just for retention, a bevel would be an absolute clinical requirement. And in all other cases I would still place a bevel for good marginal bonding, good esthetic gradient, and to allow a more conservative preparation that still removes all of the surface decalcification. But be careful about local beliefs here.
For the class II composite preparation it is clear that there should be a gingival bevel - and yet it is rarely done in practice. I sometimes think that the lack of requirements for a bevel on clinical board exams is more a reflection of what the examiners do in their practice - as opposed to what the schools teach. I admit, I have not been in any regional board calibration meetings for years, and never got the chance to ask this question, but that could be it. What will you choose to do in your practice? Personally, I won't place a class II composite when I do not have gingival enamel to bond to, and I will always take that extra 30 seconds to place the bevel - why not?
The other interesting thing about the class II composite preparation is the proximal wall exit angles. If they are flared - i.e. the angle of tooth structure is obtuse, the end of the enamel rods is exposed by the wall itself and no proximal wall bevel is necessary. On the other hand, a more conservative preparation can be made by underextending facially and lingually and then removing the last of the decalcification with the bevel. On the other hand, in the dental community, the burs that are most commonly used for class II preparations are too large to permit a conservative class II preparation anyway - whether amalgam or composite.
So we basically do the class II composite preparation just as we do the amalgam - the same technique exactly, but we flare the proximal walls a little, and bevel the gingival margin. The isthmus width can be smaller, the "axial depth" can be smaller, but otherwise it is the same in most respects.
I'd like to hear about what experiences you might have observing dentistry in the U.S. in the area of composite preparations. Many of my students are dental assistants, and they always have something interesting to say about how dentistry is practiced in their office. Generally, not how it is taught!