 Hello everyone welcome back to another session in dentistry and more topic for today is resin bonded fpd. So fixed partial dunger we commonly follow a peculiar scenario that is if you are replacing the 3 6 so we just cannot put 3 6 here sometimes we can put it like that but it need to be an implant but we are talking about fixed partial dunger not an implant. So in that case we need to take support from 3 5 and 3 7 ok. So what we do is we plan a 3 unit crown. So we plan a 3 unit crown so we will make a 3 unit crown. So in order to get the support for 3 6 3 5 and 3 7 are sacrificed because it was natural tooth it had no problem it was caries free it was sound still we sacrificed 3 5 and 3 7 just to get the support for 3 6. So that is a common scenario of fixed partial denture but the resin bonded fpd is having an innovative idea that is we are not going to sacrifice 3 5 and 3 7 what we are doing is we are keeping an additional attachment from the 3 6 that is the pontic the attachment will be towards 3 5 and 3 7 there will not be much destruction of 3 5 and 3 7. The tooth structure will be maintained the tooth structure will not be destroyed much a little bit of enamel will be etched or other procedure but it is very much differs from the conventional fpds. So it is nothing but the resin bonded fpds we use resins to bond to the abutment teeth in order to get the support for the tooth that is the concept of resin bonded fpd. So resin bonded fpd is a process that requires minimal removal of tooth structure particularly for the abutment teeth that are intact and caries free. So the primary goal of the resin bonded fpd is a replacement of missing teeth and maximum conservation of tooth structure. So as per definition it is a processes that is looted to tooth structure primarily enamel which has been etched to provide mechanical retention for the composite resin. So we use resin for the mechanical locking and also enamel etching will be there. So we use wings like planks or apparatus which will be attached to the abutment tooth using a mechanical lockage instead of destruction or preparation of tooth. So there will be very minimal preparation of the abutment tooth but we will get the enough support. So once the acid etching technique has been popular the acid etching technique was popular the resin bonded fpds are introduced to the market because it involves acid etching. So in these fpds like I told there will be metal framework which is like wings attached to the abutment tooth. So what exactly is the difference between conventional fpds and resin bonded fpds? So in conventional fpds the greater amount of tooth structure destruction will be there but in resin bonded fpds there will be very minimal tooth preparation requires and the conventional fpds aesthetically may not be very pleasing but in resin bonded it can be given in both anterior and posterior region because of its pleasing aesthetics. And missing tooth as well as the abutment teeth has to be replaced in case of conventional fpds but in resin bonded fpds only the missing tooth is replaced the abutment tooth is not affected. So what are the types of resin bonded fpds? It's a very commonly asked question the first one is crochet bridge the second one is marieland bridge the third one is cast mesh fpd cast mesh fix partial denture and the fourth one is virginia bridge it differs from the mechanism of bonding. So first one is raw shade bridge so as you see the picture here it have funnel shaped perforations in the wings. So I told you there will be wings which is starting from the pontic towards the abutment okay so this wings having perforations to enhance the retention you can see it here so there will be combined slain coupling agent to produce adhesion to the metal. So there will be a coupling agent which will produce adhesion. So the second one is marieland bridge in marieland bridge adapted electrochemical pit corroding technique that is 3.5 percentage of nitric acid is used for 5 minutes with current of 250 milli ampere followed by immersion of 18 percentage hydrochloric acid in an ultrasonic cleaner for 10 minutes. So this is how we create porosities for the adhesion that is electrochemical pit corrosion 3.5 percentage nitric acid for 5 minutes then 250 milli ampere current with 18 percentage of hydrochloric acid for 10 minutes so the resin alloy bond will be having a strength of 27.3 megapascal. So this specific to non beryllium nickel chromium alloy which is 2.9 times almost 3 times more retentive than the perforated type 3 times more retention so but this is a technique sensitive one over etching produces electro poly surface the next one is cast mesh fixed partial denture so it is non etching method okay non etching method unlike the other two where a net like nylon mesh is placed over the lingual surfaces of abertment teeth you can see here in the cast the mesh is incorporated in the retainer wax pattern so if the mesh blocked out by the wax when investing retention will be compromised so it should not be blocked out so it is a non etching type where we a net like nylon mesh is placed over the lingual surface of the abertment teeth in the cast so the mesh is incorporated in the retainer wax pattern that is the concept of cast mesh fpd which is a non etching type whereas a Virginia bridge it is by the incorporation of salt crystals into the retainers to produce roughness in inner surface that is why it is known as lost salt technique lost salt technique so retainer pattern fabricated with resin with 1 mm wide crystal free zone around the outline the salt is dissolved in water after the resin polymerizes cubic voids act as a retentive component so aluminum oxide used as a surface treatment that is air abrasion to improve bonding with resin so that is a Virginia bridge it is also known as lost salt technique so what are the advantages of this resin pointed fpds the main advantage is there is no LA that is local Anastasia because most of the tooth preparation involves just enamel then it is mostly involving just supra gin javel margin there is no sub gin javel involvement and it is having very minimal tooth preparation so it is very conservative minimal tooth loss then it can be rebounded if the axial adhesion get loose bounded so these are various advantages of resin bonded but the disadvantages are the some amount of some sound to structure has to be lost there will be enamel loss that is invariably associated with the bonding process then the longevity that is a bigger problem compared to the conventional fpds and the alignment correction is not possible alignment correction is not possible with this because sometimes the tooth will be in a buckle position or lingual position or major or distal we just cannot tilt the alignment if it is in a conventional fpd we can just alter the preparation and make the alignment in a parallel way but this is not possible because we are just attaching some wings like apparatus on the apartment there is no change in the growth structure of the apartment so alignment is not possible to be corrected so next is temporization is not possible that is a provisional processes cannot be fabricated provisional restoration is not possible not possible that is temporization is not possible so we are directly attaching it to the tooth so we were talking about the advantages and disadvantages now let's see what are the indications it is indicated when carries free abutment teeth are present carries free abutment teeth and mostly on the mandibular incisor replacement incisor replacement or maxillary incisor replacement or periodontally compromised periodontally compromised abutment with reinforcement of resistance feature while preparing the tooth periodontally compromised tooth or single posterior tooth replacement single posterior tooth replacement so these are indications but it is contraindicated when there is excessive carries nickel sensitivity and deep overbite when overbite is more you just cannot perform this one so what are the things we should think about while doing tooth preparation that is axial reduction and guide plane on proximal surface with slight extension onto the facial surface which can provide a facial lingual lock ok so facial lingual lock is mainly based on the mechanical bonding so axial reduction and guide plane on proximal surface with slight extension onto the facial surface so it will create a facial lingual lock and we should give a light chamfer finish line light chamfer finish line with one mm supra chanchavali to enhance resistance 180 degree tooth preparation is to be done 180 degree tooth preparation to enhance the retention so the large surface area is involved to improve bonding because it is mainly based on the mechanical bonding and occlusion clearance sometimes can be employed vertical stops are placed like flat counter sinks on lingual surface of incisors singulum rest on canine occlusion rest seat on primolars and molars so grooves are used near the fascia proximal line ankle then an opposite side of singulum or lingual cusp creating a wraparound effect for mandibular primolars full coverage of lingual cusp is done so molars also have lingual cusp coverage preparation inlays can be attached to anatomical grooves on distal lingual surface axial coverage extending through proximal contact to connect with occlusion rest so we need a high speed hand piece articulating ribbon small wheel and short needle diamond bird so all these things we need so that was all about our topic resin bonded FPD so it was a newer technique after the acid etching technique was introduced because the conventional FPDs are having the main disadvantage of tooth destruction the abortment tooth are sacrificed for the retention of the pontic for the tooth to be replaced so if we have an option where it is indicated when the abortment is carries free and all other indications are fine so we can go for a resin bonded FPD where wings like attachment from the pontic towards abortment will give proper retention so it has many advantages such as very minimal destruction because it is just attaching on enamel and at the same time there is some problem too because it just cannot tell the angulation of the abortment because there is no gross change of the shape or alignment of the tooth so hope you understood this concept of resin bonded over the conventional FPD and these four are the various types that is Roshid Maryland cast mesh and Virginia this will be asked separately as a short note and this resin bonded as a short essay so you can write about its indication contra indication advantage disadvantage and this type with pictures so I'll come with a new topic in the industry and more thank you