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Mahmoud Massalha Prostho Sheet #13 part 2 31/12/2013

2nd part of Sheet #13:

After we checked all the peripheries (labial and buccal of upper, and labial, buccal, and lingual of lower) How do we do molding to the lingual? We ask the patient to move the tongue to right, left, slightly forward and touch the palate, and then you see the borders in the same way. If we got an overextended area, you mark it with a pencil and trim it, then apply the PIP (pressure indicating paste) again, replace it (the denture), then mould it and then recheck. If there is no ripping off the PIP then it's correct. However, if it's (the PIP) gone off the borders then there still overextension and you have to trim it again, and be careful you don't do excessive movements by putting pressure on the cheeks because it's not a functional movement.

And now after checking the peripheries you check the polish surface. You have to apply PIP on the polish surface. As we see in the picture below (in the upper part) there are root prominences which you can trim them a little bit (do NOT eliminate the root eminences), and then you check the part of the polish surface which is away from the root eminences. If you look at the second part of the picture you can see a thickened area which indicates excessive contact, so you have to reduce the thickness.

And the same thing should happen to the polish surface of the palate. And we can see in the picture below that the PIP was removed, so it means that you have to trim it until the thickness is reduced because it affects phonetics. So finally you get a thin palate.

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Now you check the retention of the dentures, and that can be achieved by having properly extended borders and conserving the undercut areas which give the retentive property of the denture. First, you check the retention of the upper denture. We have anterior retention and posterior retention. But before we go deeper, we need to remember the definition of retention which is resistance to forces acting to displace the denture away from tissues. So to see the resistance of the upper denture you try to pull it down. To check the anterior retention you hold the anterior teeth and try to pull the denture down and there should be some kind of resistance (you should get a retentive denture if the borders were fully extended and there has to be resistance to pulling movement). To check the posterior retention which means breaking the seal posteriorly, you place the fingers behind the canine area anteriorly and you try to flip the posterior part of the denture down and there should be resistance to displacing the denture posteriorly, and if there is no resistance this means that there is no retention and the denture will drop. You as a dentist have to diagnose the problem, is it because the flanges are under-extended or they are overextended, is it because the post dam is under-carved or it is over-carved or maybe misplaced, so you have to be able to diagnose the problem at this stage and at the time of post-insertion.

Note: Sometimes the reason is over-supported borders which prevent the denture to make a proper seal.

As we said above that the overextension is one of the common reasons for dropping of the denture out of the patient's mouth. For example if it's extended to the mobile soft palate area, as soon as the patient talks, opens his mouth, or swallows food it'll immediately drop. So if you suspect that the problem at the post dam area, locate the vibrating line by asking the patient to say a long "AHH" and then insert the denture and see if it is overextended beyond the line then you can trim off the excess (this makes a big difference because once it gets over the line it will lose retention).

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You repeat the whole thing for the mandibular denture which takes a longer time because you have to check the retention of the lingual side as well. So, checking anterior retention for the mandible is done by trying to lift the denture vertically upward. And you check the posterior retention by placing your fingers behind the lower anteriors by trying to flip it, and as a result of that there should be resistance from the side of the retromolar pad where displacement should be upward. And as for the upper denture, the same can happen to the lower, it can get overextension or under-extension which is checked by the PIP. However, it's better to get overextension rather than under-extension because under-extension is difficult to adjust.

So far we have repaired, finished the fitting surface and the borders as well. And now we'll check the occlusal analysis. If your technician has done the laboratory remount, there should be a minimal adjustment done, only because there were problems transferring the occlusal relationship from the intraoral to the articulator, or if you didn't do a proper occlusal registration for a proper relationship for the patient, like for example: centric relation doesn't go inside the centric occlusion while you supposedly should establish new centric occlusion position on the complete denture that go inside the centric relation. (As a reminder: centric relation is the most retruded position of the mandible related to the maxilla) you don't push the mandible to that position, but you guide the mandible for the complete denture patient to go for centric relation. For normal people centric occlusion doesn't usually go inside the centric relation. It's an acceptable deviation because it occurs in more than 70-80% of the people and it does not harm. However, if you try to bring the mandible back to the most retruded position, you'll find out that it's not the maximum intercuspation position, and only few cups are touching. For the complete denture patient if you try to bring the mandible back there must be a maximum intercuspation because it's the only repeatable position that you establish occlusion at.

If you insert the dentures inside the patient and try to guide the mandible to centric relation and the patient has only few contacts (while we want even contacts on the functional cusps as we said) then they are considered as premature contacts, or if they have an open bite anteriorly (this is a common mistake because of proof falsking and packing of acrylic. So there might be occlusal problems that might be skipped in the laboratory remount and that's why during clinical analysis we need to do another remount called clinical remount (we call it clinical remount because it's done in the clinic, then we do registration, and then we transfer it to the articulator and we use quick setting by the plaster paris for the mounting then we use the occlusal adjustment while the patient is seated on the chair).

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It has to be done as a routine procedure which means that it's easier to do the procedure extraorally because intraorally is really hard to ask the patient to repeat the movement in the same position. There are many reasons which make this hard to be accomplished intraorally such as the saliva which makes the visibility not that good, patient keeps shifting, it's time consuming, tissues might get distorted, and they might miss a psychological factor like if you keep asking the patient to close his mouth, and by the time you get tired, appear to be bored, and sweat, so these make the patient feeling that there is something wrong in the denture.

So if you get to do this procedure in front of him you have to be confident enough as it appears to be as a routine procedure for you so the patient feels that it is a routine procedure as well (actually there is no need to do occlusal adjustment, but this is in case if you or the technician has done a mistake and you're trying to fix it). Remember that if you want to do remounting our problem is that there is no cast, so we're going to do pouring around the denture from your cast, and as you remember we have made an occlusal jig to locate the upper denture on the articulator, so place the denture in the jig and then place wet gauze (or wet cotton rolls) inside the undercuts (we don't want a cast, we just need something to hold the dentures to do the adjustment on the articulator) to prevent the plaster of the clinical remount to go inside the undercuts of the denture and for easier separation later on. And you mount the upper member on the articulator, and then you retake the upper denture, insert it and then you place bite registration material in between the teeth, this can be anything (the most accurate bite registration paste is the silicon, it's easier to use, and come in the form of gum, easier application… the most important thing is not the material, so it can be silicon, wax, aluwax… however, what we care mostly about is getting the patient to close in the centric relation whether it go inside or not with the centric occlusion). So you place it and manipulate the mandible until it goes back and you ask the patient to stop closing when he feels that the teeth begin to contact with each other ( Why?!! .. because if penetration has happened in the material, and the cusps touched each other this tells that firstly there probably was a premature contact and then the patient slides to maximum intercuspation, we don't want the centric occlusion that the patient eventually reached, we want the precentric occlusion which means the beginning of the contact which is the premature contact) then you observe the material if there is show-through then you have to redo it because this is not a precentric, this is centric occlusion and there might be a shift between centric relation and centric occlusion.

And you can actually repeat and redo until you make sure that this is the correct relationship that you want and there is no shifts in the mandible either forward or to the sides and then you wash it, you mount and place the lower and upper on the articulator, you hold them upside-down and then you mount the lower denture according to this relationship that you recorded, and after setting of the material you can use quick set plaster of paris to set quickly, before attempting to trim the teeth you can recheck if this is the correct relationship intraorally, and then you remove the bite registration material, and restart the selective grinding.

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The "S" sound, we check it at the time of free-way measurement.

When we say "S", there's a touch between the incisors; they become close together and posterior teeth, shouldn't be contacting, so if the "S" sounds like "SH" or "TH" like in "ث", this might indicate that there's something wrong in the setting, and you should have checked this at the time of bight registration and the try-in, because if there is a problem in phonetics, at this stage you can't change anything! You have to remove the teeth and re-set them.

So, you should have done this previously.but you have to keep in mind that sometimes when patients receive the dentures, especially the first-time-denture wearers ( first time they wear dentures), phonetics might need time, you have to give them a period of adaptation of one week to adapt to the denture, then after that, you check phonetics(you also check it at the time of fitting the dentures) but you decide if a problem is present in phonetics or not after a period of one week, so if there is a problem and the patient didn't adapt to the new denture(the letters are still pronounced incorrectly) then the there is a problem, and the problem might be in: 1.setting the teeth 2.thickness of the palate 3.position of the teeth … etc.

so here you have to solve the problem(after the discovery of the problem after the period of one week), but at the time of fitting the dentures, if the phonetics aren't that good(unless there was an obvious problem) you don't do adjustments at that stage.

Now, finally you check esthetics, and patients should have the chance to say anything about esthetics at the trial of wax rims. Ex. In some countries they let the patient to sign to assure their satisfaction, so when he comes at the time of denture fitting ( when dentures are already flasked and no more adjustments can be done) and complains about the esthetics, it is his problem and not the dentist's! and he should pay if he wants to change anything.

Remember: esthetics quality is as important to the mental health of the patient as the biological and technical qualities are to his physical and dental health!So it's your responsibility to give time to the patient at the time of try-in(wax rims) so he could make up his mind concerning the esthetics.Now, because you have done lots of adjustments, you have to polish the denture and do the minor adjustments (finishings).

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There are kits for finishing and polishing; special polishing kits(from breslin; the name of the brand, not sure about the name though!), then you use a special polishing paste on a felt-cloth wheel.

Then you provide the instructions for the patient for proper denture and oral hygiene.

Lots of patients don't read written instructions, but anyway there must be written instructions for the patient as well as instructions told verbally.

Special attention for those who wear dentures for the first time, because it might be uncomfortable for them for the first few days; there will be excessive salivation, eating will be difficult, and they have to chew on both sides simultaneously soft, small lumps until they master chewing on the posterior teeth and then they start incising on the anterior teeth afterwards.

They have to remove the dentures out of their mouths while sleeping. They have to clean them after each meal with a soft brush without a tooth-paste, because it might cause abrasion, soap is fine.

They have to hold it properly over a sink so that it doesn't fall and break. They mustn't put them in hot water because hot water causes discoloration to the dentures and basically affects the esthetics.

There are lots of instructions, those of hygiene are the most important, because lots of patients think that by only rinsing them under water it'll be enough! Well, it's not!Actually once every week they must put them in a diluted hypoclorite solution, and let them bleach to remove the debris that stick and which are difficult to remove, also don't forget about the brush(medium or soft) to remove all food debris and the plaque that accumulates on the teeth of the dentures.

Also, you have to get the patient in a review appointment, ideally one week after the fitting of the dentures to correct all the impingements, ulcerations, difficulties in speech, problems or complaints the patient might have.

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This(the review appointment) should be given to the patient routinely, it's a must! You have to give the patient a fixed review appointment and not just to come when there's a problem.

You have to give the patient instructions and tell him at the time of fitting the dentures.

He won't come to the post-insertion appointment sad and complaining about the denture not being good and uncomfortable! If you warned him before that there will be a review appointment for adjustments of any problem the patient might have, then he would feel that the dentures are fine, they just need to be adjusted a little bit, so proper adaptation will occur.

So, the review appointment is an essential routine that should be given to the patient.

Usually patients with complete dentures keep coming with more than one review appointment, especially the very old patients and those who had old dentures and you adjusted on them to the ideal way (they find a difficulty in adaptation to the new situation).

So, at the time of review appointment, we have to do differential diagnosis for the post-insertion or post-fitting problems.

If you have followed all the steps correctly without any drastic mistakes in the lab, there will be few problems occurring that you have to adjust.

There are a number of problems we'll talk about them next year more thoroughly that you need to adjust, like if the problem is on the ridge … if the problem increases with time during the day … what are the manifestations and causes like an overextended border for example … etc. (don't worry about these now).The basic rule: never adjust unless you can see exactly where to adjust.

Keep in mind that the patient can't actually locate the problem(where the problem actually is) because he has his teeth all lost and when he feels the pain along the whole denture, he can't locate where the problem exactly is!

You can't depend on what the patient tell you because they're usually wrong locating the source of the problem, so you have to spend time looking and thinking.Always use indicating media: - pressure-indicating paste for the peripheries of the fitting surface - articulating paper for occlusion.

You have to ask certain questions: where is the problem? > easier when using special indicating of 13


paste, when is it? At chewing only, then it's probably an occlusion problem, for how long?does any thing make it worse? > like when opening his mouth wide, the denture falls off.

Have the patient demonstrate the problem, let the patient tell you what exactly occurs or what he feels, like when he opens his mouth, he feels like there is a sore throat or the flanges of the denture irritates the soft tissues, then the problem is that the flanges are overextended.

There should be a limited number of problems, which may be :1-the denture base making an impingement.2-there are interferences in the occlusal relationship (in protrusive, centric or eccentric).3-lack of retention (borders, saliva…)4-vertical dimension problems.5- allergy (very rare)to acrylic.6-infection (is common).7-tooth position also can be a problem.8-phonetics.

For the denture base, we already checked at the time of fitting that no sharp spicules or edges are present, and should be adjusted at that time.

If there's tissue impingement, at this stage you can precisely locate where the impingement is.

What you can do instead of placing pressure-indicating paste on the whole fitting surface, is just you place it at the area (for example maxillary tuberosity) and the paste will be displaced, so you trim it off.It's much easier than the blind wearing that we used to do at the time of fitting the denture.

We don't care about the incisal pin anymore, you drop the teeth until they have a proper contact and you follow the same principles of selective grinding that you followed previously when doing the laboratory remount, you do centric movement and then with the vertical dimension, then you do eccentric movement (lateral then protrusive). Use articulating paper with minimal thickness you can start by thicker ones and go down to thinner ones, ensure that there is no contact on anterior teeth in centric occlusion, there is uniform simultaneous, bilateral centric contacts, and smooth excursive movements.

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We have to have balanced occlusion in the lateral movement of both sides and in the protrusive and there should be light grazing contact of anterior teeth in the excursions, and then intraorally verify the contacts and make sure that there is sufficient 2-4mm of free way space for the patient. After checking occlusion (it doesn't take long time because it is easier to do on the articulator) you check the phonetics (which is the last step we do) if your setting is correct, so all letters should be pronounced correctly. For example you have to know that the 'F' sound is produced by the touching between the upper teeth and the lower lip (and the 'V' is the same), so if the 'F' and 'V' sounds are not correct, it means that we might placed the teeth too far or too low, or maybe they are too much pointed forward or backward. Then the 'S' sound we check it at the time of free way measurement, where there is a touch between the incisors close together and the posteriors should not contacting, for example if the 'S' sounds like 'sh' or 'th' this will indicate that there is something wrong in the setting (you should've checked this at the time of bite registration of the try-in because if there was a problem in the phonetics at this stage you couldn't change anything, you have to remove the teeth and reset them). You have to keep in mind sometimes patients when they receive the denture (especially the first denture wearer) the phonetics might need time of adaptation which may last for one week to adapt to the dentures, and then after a week you check the phonetics if they are pronounced correct or not, if they are not correct it means there might be a problem in the setting of the teeth or the thickness of the palate or the position of the teeth (or whatever)… and then you will have to solve the problem. However, at the time of fitting of the dentures if the phonetics are not that good unless it's a very obvious problem you don't do adjustment at this stage.

Now Finally you check esthetics.

Never adjust, never trim tissue impingements/areas causing tissue impingements unless there is pain through the pressure indicating base. Usually if the problem is from the denture base the patient will tell you that the area is sore at all times until he can no longer tolerate the denture. That is the usual complain regarding tissue impingements.

If this worsens during the day it might be due to occlusion, so you have to differentiate between denture base problems and occlusal problems.

(This will be given to us in more details next year)

We only apply pressure to the area that the patient suffers from pain at, and trim that area, but you must be careful with undercut areas not to lose retention.

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Occlusive problems

- Are common: For example it is common to have insufficient freeway space in which the patient complains that he feels that the teeth are too high, and the problem worsens during the day and at the end of the day he complains from strained jaws because there is no sufficient freeway space or that the vertical dimension of the occlusion is increased.

While if there is excessive freeway space that patient will complain that they have to move their jaws a long distance until they bring the teeth together to chew and efficiency of chewing is not that good (inefficient mastication ).

-If there is an excessive vertical dimension we can trim of the teeth.

-If the freeway space is too large we will have to reregister the occlusal relationship and set the teeth.

Usually occlusal problems are very difficult to determine intra-orally because when the patient is in pain at a side his reflex will be to move away from it.

Again we have to remount and reset the teeth.

Retention problems

- These problems are from overextension or under extension

We do apply pressure indicating base and if it remote from the border then this is a case of overextension, and we trim it until we get a thin layer of pressure indicator on the border.

If it is severely under-extended and the denture is not retentive then we will have to adjust the border and redo the base.

Again, we learned how to check for the retention of the denture of the upper and lower dentures.

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The post dam area is an important retention area of the upper denture, we have to locate the vibrating line. Of it is overextended we can trim it, if it is under extended we have to retake the impression and redo the base.

Usually if it is over or under-extended the patient will complain from food/bubbles getting under the denture, and with no posterior seal; the denture will drop.

It is easier to correct overextension than under-extension.

Regarding instructions we have to stress oral and denture hygiene of patients. If he comes to an appointment with a filthy denture it shows that the end result will be disastrous.

Usually when there is poor oral or denture hygiene, the patient sleeps wearing the denture, with generalised inflammation of the gum.

Overextension of the borders might cause:

- An ulcerit would be localised at the area of overextension characterised by redness - The denture falling out of place due to lack of retention

Allergy is a rare condition associated with poor oral hygiene and generalised inflammation on the whole denture bearing area. In this case we will need to apply more proper oral hygiene instructions to the patient and place stress on cleaning the dentures.

Problems regarding tooth positioning that if the teeth are not properly located then the big problem will be instability in the denture.

Remember when we checked stability of upper denture we used to alternate pressure on both sides.

One of the most common problems, that the teeth are set too far buccally or too far palatally or lingually and this will cause instability of the denture and also difficulty chewing.

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Another example: In cleft position of the tooth if upper and lower teeth were set in a way that there is no horizontal over-jet, there will be a problem of cheek biting because uppers should overlap lowers and give more support. if there is no over-jet and uppers and lowers are at the same level, the patient will complain from cheek biting. You can solve the problem sometimes by trimming off the buccal walls of the lower teeth. If it is severe then you will have to re-set the teeth.

Aesthetic problems should have be solved previously. If the patient has aesthetic problems and phonetic problems at this stage then you will have to reset the teeth and change the position of the teeth to the right place.

Some areas are very common to need adjustment at the time of denture adjustment or review appointment, some of which are:

a. Labial Frenum – requires appropriate relief, if wasn’t properly relieved the patient comes to the review appointment having either ulceration or the denture drops.

b. Hamular Notches – also common areas having either ulceration if it is over-extended or the denture drops.

c. Midline Fulcrum or Midline Raphe - in the middle because they retain mucosa.

d. Zygomatic Impingement on the buccal of posteriors - because of lack of proper molding for that area.

e. Lingual Frenum and Labial Frenum in the mandibular arch – lingual is very common to be overextended it might either cause ulceration or displacement of the denture.

f. Retromylohyoid – also very common to be over-extended and usually the patient complains from sore throat and also that the denture moves upon swallowing.

g. Buccal Shelf - can be over extended in width and depth.

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Regarding phonetic problems; always allow time for adaptation. Some of the problems might be solved if you increase the thickness of the palate by adding a piece of wax on the palate. If the phonetics improve you send it to the lab to add acrylic to that area.

If poor phonetics is due to poorly positioned anterior teeth, you have to remove the teeth, re-place and remake the dentures.

Your Colleague: Mahmoud Massalha

I apologize for handing in the sheet in such untimely fashion.

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