 Hello everyone, welcome back to another session in dentistry and more so then we have a very important topic from process analytics That is relining and rebasing So the name gives a clue about the procedure that is Relying and rebasing that is we are either doing a small procedure complete Reconstruction of a old denger a denger which is having fitting issues So we are doing additional work on the existing dentures. So that is Relining and rebasing So as per GPT The relining it is a procedure used to resurface the tissue side of a denture with new material layer Okay, that is we are resurfacing the tissue side of denture so that's producing an accurate adaptation to the denture foundation area Since it is having the fitting issues. So we are resurfacing the tissue surface So it is usually carried out when the fitness of the denture is compromised and it is not necessary to construct a new one You can just reline it Whereas rebasing it is a laboratory process of replacing the entire denture based material on an Existing processes without changing the occlusion relationship or dental arch So it is performed for extensive tissue changes and the entire denture base is changed following impression procedure So that is the difference between relining and rebasing so what are the indications of Relining the first thing is for adaptation adaptation the adaptation problem That is adaptation of the denture base to the ridge then patient with complaint of looseness or instability of denture When patient complains the dentist about his dentures looseness or instability following a long standing history of comfort and satisfaction with the denture foot and Maybe three to six months After the construction of immediate denture There also we need to do the relining or for patients in category of geriatrics or Chronically ill so such patients also we need to do the process that is relining geriatrics or Chronic ill patients or The affordability some patient Might not be able to afford a new denture. So in such cases also we can just do the relining It is not costly as creating a newer denture So rebasing is indicated when there is loss of retention and stability and regarding the contraindications So this is indications contraindications If there is excessive ridge resorption if there is a TMJ problems if there is any a TMJ problem and Dentures with poor aesthetics Dentures with major speech problem. So aesthetic compromised dentures dentures which create Major speech problem minus speech problem will be there definitely And if there is any presence of Osceous undercuts So in those cases we just Cannot do This process of relining or rebasing in those cases We might need to create a new one rather than Reconstructing the existing denture So the first step of relining or rebasing is a Preparation so preparation of the tissue or preparation of the existing denture So tissue preparation involves the oral mucosa it should be free of any type of irritation and The dentures that should be left out of the mouth two or three days before making the final impression so two to three days without denture and Zero irritation there should not be any irritation for oral mucosa And hypertrophic tissues should be removed The hypertrophic tissues So removal at night And massaging the Gums massaging Gums So these are Preparatory things we should do on the tissue. So these are the tissue preparation Uh procedures And now let's see what are the denture preparation procedures So a border extension should be checked properly border extension And it should be corrected undercuts should be relieved Undercut should be relieved and occlusal disharmony is corrected by selective grinding selective grinding for occlusal disharmony And there should be accurate posterior bilateral seal establishment So next we have the relining techniques. So relining techniques are basically classified into the direct Methods and indirect methods in indirect method. We have static and functional static means the Occlusal dentures or the dentures are in a static position. There's there's no functional moments like swallowing Uh, or other lip movements. So nothing will be there We can do it in open mouth and closed mouth way Uh, the next in indirect method is functional where we, uh Reproduce or simulate all the basic functional moments such as chewing Smiling and other lip and cheek movements So in direct method it is also known as chaiseid technique chaiseid technique So cold cured acrylic or tissue conditional material is used for this chaiseid technique But, uh, they're not very durable. So direct Relining is less time consuming So the fitting surface of the denture is clean Roughened and slightly reduced as you see the picture here Then the flanges are trimmed just to reduce the danger of over extension and the undercuts are removed Then we apply the lubricant over the polished surface to prevent the new resin material to adhere on it and The new self curing relining material is then mixed and applied to the fitting surface So hope you know what is exactly The polish surface and what is the fitting surface fitting surface is the surface which comes in contact with the tissue and the Opposite one is polish surface So we put lubricant over the polish surface to prevent the new resin material to adhere on it And the new self curing relining material is applying on the fitting surface So the denture is inserted and the patient asked to bite gently on the denture To ensure that the occlusion is not altered by the procedure Then the motor molding can be carried out and the denture is kept in situ for about five minutes after which it is removed and carefully examined So what are the problems associated with this direct or trace side Technique the first thing is material is porous And has an unpleasant odor Then the excess monomer which can leaches out and may irritate the mucosa And there will be exothermic heat Which can burn the mucosa And it has poor color stability And if it is not positioned correctly it can lead to gross discrepancies So that was about The direct method now we have indirect method and indirect we have static And functional So in static again, we have open mouth and closed mouth Okay Now let's see what is open mouth technique. That is an indirect method. So here the dentures are used as special tray Okay for making the final impression. We are using the denture itself as a special tray Okay, not correcting On the existing dentures. We are using it as a special tray for making the final impression Then we keep tissue stops Which are prepared in the denture using a loaf using compound to maintain the vertical dimension occlusion plane and aesthetic position of the anterior teeth And these tissue surface and borders of the dentures are trimmed by one millimeter Then these borders are molded with green stick compound Then we take the final impression with the zinc oxide paste So there'll be green stick Our usual procedure will be carried out. Then the final impression with zinc oxide huge north And impression of maxillary denture is made then followed by mantibular and new centric relation Is made using the inter occlusion check methods So this is indirect method. Okay. Direct method is quite easy. We directly just trim off the Surface and apply the gold cure and take impression. But this is indirect method. This is exactly Like how we do our procedure in the original preparation of dentures we Use the existing denture as a special tray only the primary impression step is missing here So the special tray is made that is our old denture. Then we put tissue stops Then the green streak compounds then the zinc oxide huge north and the new centric relation is made and finally The inter occlusion check So that is open method where the patient's mouth is opened first maxilla is made then the mandible And the advantages are the selective impression is made without any occlusion Interferences the operator need not worry about making jaw relation while making impression As a separate record is made The centric relation record is verifiable. Okay. So these are the advantages of Open method which is coming in static and indirect method But the disadvantages Are the chances of increase in vertical dimension even though tissue stops are provided. So there is vertical dimension may be increased And high possibility of denture moving forward And the it is a very demanding and a laborious technique. It is almost as like Making a new denture And it requires more clinical and laboratory time So that is all about the open technique. Now we have the closed technique So how it differs from open technique Here the difference from open technique The closed technique where the maxilla and mandible dentures are kept in position And taken the impression Simultaneously not one after another. So in open technique first the maxilla will be taken then followed by mandible here simultaneously Taking impression that is dentures kept used as a special tray for making the final impression similar procedure Then the tissue surface and the borders of the dentures are trimmed one to two mm Except for the posterior border of the maxillary denture Then borders are molded with our green stick compound then final impression with zinc oxide huge knot And There is no Separately tricking the Centric relation because it is already in a closed position So the advantage is the less chances of increase in vertical dimension Unlike our open method And it takes less time because we are doing it simultaneously And chances of denture moving forward during the impression is less because both are in a Closed mode position. So there is less chances. It is being forwardly placed So vertical dimension will not be increased It takes less time and the chances of denture moving forward Taking impression is less But the problem is If existing errors in centric occlusion can produce pressure points and inaccurate impression And hydrostatic pressure in palette during impression Making and packing of acrylic can still cause increase in vertical dimension So that is also there enclosed More technique Because of this hydrostatic pressure in palette during the impression making and packing of acrylic Can result in increased vertical dimension And there can be inaccurate impression because of the existing errors in the centric occlusion If already that error is there in the centric occlusion There will be inaccurate impression will be obtained So we finish the direct technique and the static methods of indirect technique next we have The indirect technique That is a functional method Functional method So functional method it is simple practical and very popular So tissue conditioners are used as an impression material The areas of the denture which are not to be contacted by fluid resin are painted with a lubricant Then powder and liquid of the soft liner are mixed according to the manufacturer's instructions And allowed to polymerize in the mixing cup then on Creamy and fluid stage what we do is we pour the material into tissue surface and when material Flow stopped we insert It into the patient mouth. So patient is instructed to close in centric Uh my relation maintaining the vertical dimension And we ask the patient to make all the active and passive moments That is the methods of border molding Such as functional moments like swallowing smiling speaking until impression reaches a more stable Rubber like stage. So that is the difference between functional and static static such Uh moments are not there here. We are asking the patient to simulate the functional moments So after removal of excess tissue conditioner Then voids are corrected with new And we need to recall the patient After three to five days when the patient returns The under extensions denuded areas and pressure sports can be corrected by trimming Or maybe added adding new material So the material is changed periodically till the tissue returns to a state of health And then the patient is scheduled for final impression And as in gauxite usually impression paste or we can use a light body wash impression Uh over the conditioning material and we can we can verify it This method is similar to the functional reliant technique So this is uh procedures That is done in patient's mouth Now we have the lab laboratory procedure. They are Lab procedure. They are the flask method Then the articulator method flask articulator and The jig method So the first method flask method So the reliant impression is poured with dental stone Then the master cast is poured around the impression similar to the original master cast by Beading and boxing So the cast provides the surface against which the denture is reliant by invading it in a processing flask Then the flask is formed to soften the impression compound before opening it to remove the impression material Separating medium is applied on the plaster and stone mold And heat polymerized denture base resin is packed into the mold Then the flask is closed and clamped to ensure maintenance of occlusion vertical dimension After processing uh flask is cold slowly and the denture is retreat from the stone Finished and polished. This is how we Perform the flask method. So this we are familiarized Uh with this process In our original denture construction is almost same as this So here the reliant impression is poured with the dental stone at first Then the master cast is poured around the impression similar to the original master cast How we do by beading and boxing then this cast Uh provides the surface against which the denture is reliant by invading it in the processing flask So that is how we do flask method whereas the articulator method So master cast is poured then cast not separated from the impression A layer of plaster is arranged in platform fashion on the lower member of the articulator As a plaster is set The cast with reliant impression is placed on the wet plaster Such that the teeth penetrate the plaster surface to a depth of 2 mm as you see the picture here Okay here in the first picture what you see is reliant denture with cast stabilized on a platform of Plaster to form an index. Okay, then uh can see the completed mounting of reliant impression with cast on and the articulator with Formation of index of the denture teeth. So we are creating an index of the teeth on the plaster. Okay This forms an index or key of the teeth which allows the positioning of the teeth Once the plaster sets additional plaster is placed on the base of the cast And is mounted on the upper membrane of the articulator when mounting sets The articulator can be opened and the denture with impression is separated from the cast So the denture base is waxed cast and dentures are removed uh from mounting Then we do the flasking processing with heat cure denture base acrylic resin. So that is the articulator method on The final steps are same for everything flask and articulator method only thing using an articulator We create indentation or the index of the teeth on the plaster Whereas the jig method jig is a device used to maintain mechanically correct Positional relationship between a piece of work and a tool or between The components during assembly or alteration. This is definition given by GPT It is a device used to maintain mechanically correct To correct the positional relationship between a piece of work and a tool or between the components during the assembly So first we need to see the occlusion surface of the denture on the plaster form on lower membrane of the uh relining jig Then after the stone index is made Mount the denture with the cast to the upper membrane in relined jig similar to the articulator method So this is almost same as an articulator method We are creating uh index on the plaster that is stone Then open the jig remove the teeth from the denture base and adapt the base plate wax on the cast and wax the denture Then after processing replace the cure denture Trick and correct occlusion using the indentation made in the jig Uh during the mounting of denture So that was all about uh the jig method Uh, so we were discussing the relining and rebasing process So we had direct and indirect method So direct method was chase side method indirect. Uh, we had static and functional Static uh, we had the open mouth and closed mouth technique And then followed by the lab Procedures or lab technique flask method articulator method and trick method It is uh very commonly asked short essay or short note in prosaerotic exam So hope you understood the concept of relining and rebasing. So I'll come up with a new topic in dentistry and more. Thank you