Digital Workflow/CAD-CAM PDF

Dr. Islam Abd Alraheam DDS, MS American Board of Operative Dentistry Jordanian Board of Restorative Dentistry Written by Jude Nasri Corrected by Hala Kutkut one of the ways to do a final impression is to do it digitally through scanners ü Why to go digital? Because of the drawbacks (disadvantag...

Dr. Islam Abd Alraheam DDS, MS American Board of Operative Dentistry Jordanian Board of Restorative Dentistry Written by Jude Nasri Corrected by Hala Kutkut one of the ways to do a final impression is to do it digitally through scanners ü Why to go digital? Because of the drawbacks (disadvantages) of conventional impression ü Drawbacks of conventional impression: ü Physical material properties, consistency, taste, and odor, all of which may negatively So the patient wont have a pleasant experience after taking an impression with conventional materials ü influence the patient experience. ü Clinical studies have indicated that conventional impressions are ranked among ü one of the most unpleasant experiences during fixed, removable, and implant prosthodontics If you asked your patient which step is the most difficult one he will definitely tell you its the impression step  digital impression overcomes all of these drawbacks § Why to go digital? § Advantages of digital impressions: Sometimes intraorally its difficult to see üPrevisualization of the area of interest in three dimensions things, its easier to see it on scanner when you rotate it and see it from all üReduced working time positions, you can see errors that you didn’t visualize intraorally üImproved patient-reported outcomes. üAccurate digital casts, decreasing the risk of distortion associated with the use Impression materials have polymerization shrinkage which causes distortion and this distortion of impression materials directly affects the quality of the final restoration, we don’t have this problem with digital impression üOptimize workflows due to the ability to quickly rescan a missed area. In the conventional way if you are making an impression for multiple teeth and one of the teeth comes unclear then you have to repeat the whole impression, but in digital scan you can go back and scan the area of interest again so it saves time  § Similar success rates were found for both digital and conventional workflows regarding restorative fit, interproximal contacts, and occlusion. Digital crowns also required fewer adjustments and time during crown delivery Than conventional ones. Theres a systematic review done by Rafeal in 2021 about intraoral scanning, he found out: Intraoral scanning reduces procedure time and improves patient comfort in fixed prosthodontics and implant dentistry: a systematic review o IOS is faster than conventional impressions, independent of the size of the scanned area (regardless of whether a quadrant or complete-arch scan is conducted). o IOS can improve the patient experience in the dental office measured by overall preference and comfort. o IOS as part of a digital workflow is able to provide reliable prosthodontic outcomes. Rafael Siqueira, Clinical Oral Investigations, 2021 We have intaoral scanners, extraoral scanners We can use in dental office, there are multiple scanners available in the market, the most popular one is: TRIOS from 3 shape company. it fits nicely in the patients mouth, it doesn’t need powder or special spray on teeth, you can just scan directly, 3 shape has their own software where you can continue all the work on their software. Another scanner is the true deck scanner from 3M (?) This scanner, the head is small, the problem with it that it requires that you spray a specific powder on the teeth before scanning, its a little more challenging than 3 shape scanner, still its one of the good scanners available in the market  After we scan the area of interest the scan would be sent from the scanner to a cloud, the cloud is associated with the company you are working with, they can download this scan and do your work so it reduces the shipping time that you gonna need when you are doing a conventional impression, so in digital you don’t have to pack the impression and send it and worry about the dimensional accuracy In dental laboratory nowadays we are using computer designing and manufacturing like CAD/CAM its an abbreviation for computer aided design/computer aided manufacturer In the lab they will download the scan and § Computer designing and manufacturing: have a virtual model and a die preparation, they are going to do the trimming and draw ü Model and die preparation the margins, they gonna add luting agent space as discussed before in lecture 10, we ü Trimming and drawing the margins will do the same thing we do in conventional way but in the software. ü Luting agent space  For the designing we § Different softwares available: have multiple softwares available that enable you o 3Shape to design the crown or the bridge o Straumann Visual Chairside CAD. o Glidewell FastDesign. o OneVisit Chairside by Exocad.  We do have systems where they provide you with in-office ability to mail and deliver the restoration the same day like two hours or three hours appointment like: CEREC. They have their scanner, and 2 generations; the blue cam and the omnicam and they have a milling machine and then crystallization oven so you do your preparation and scan it, design your restoration and then send it to be milled and the milling machine is available in the office so the milling will take 15 minutes and the crystallization will take another 30 to 40 mins The only problem here that you need to be well trained because you will have 2 roles the dentist and the technician Scanners are expensive so if you want to do a digital scan an cant afford a scanner you can rent it or just simply take a conventional impression and send it to a lab where they have extraoral scanner where they can either scan the impression and generate a virtual model or they can pour the impression and scan the model itself and transfer it from a real stone model to virtual one and they can continue the workflow digitally. Marginal Accuracy of Lithium Disilicate Full-Coverage Single Crowns Made by Direct and Indirect Digital or Conventional Workflows: A Systematic Review and Meta-Analysis o The meta-analysis revealed similar marginal gap values in intraoral scanners with conventional groups (p>0.05) and in intraoral scanners with extraoral canners (p>0.05). They found out that no group was superior to the other and the accuracy of digital dentistry meets conventional dentistry Mahtab Tabesh, J of prosthodont, 2022  In the conventional way they have a die so we start doing the wax up and transform it into metal or all ceramic material (discussed in details in lecture 10) here we do have wax up but its a digital one so you design the restoration digitally you visualize it and Few links that the doctor recommended watching to understand the topic you can build the whole crown or you can just have § Designing a crown on 3shape a core first and the mill it § https://www.youtube.com/watch?v=ki9vSi18I5w&list=PPSV Zirconia crowns when they are milled they come out large, § Manufacturing a zirconia crown from A to Z 20% to 25% bigger than the actual crown you cement in the patients mouth, the crown after milling should be put it in § https://youtu.be/2YYx48IIbRU the centering oven after that shrinkage happens makes the crown look like the size of the crown we use. Emax blocks come in different colors than zirconia, § Milling E.max crown zirconia blocks like stones they are really soft, when its not centered it will leave a white powder on your hands § https://youtu.be/UIghMka7zpU because its not centered, emax is a rigid material and when its milled it remains exactly in the same size of the crown, there is no shrinkage process like in zirconia  Sometimes in the lab when they mill the restoration they will only send you the restoration because they didn’t work it on a model but sometimes you really want to check the restoration on a model before you check it intraorally, so here if you have the impression done digitally you can ask for a printed model, they print the models in resin materials § Resin In this study they looked at the accuracy of the printed models versus the conventional models Digital versus conventional workflow for the fabrication of physical casts for fixed prosthodontics: A systematic review of accuracy o In vitro studies showed that additively manufactured casts and gypsum casts share similar accuracy within the acceptable range for the fabrication of casts. o The quality of scanned data, additive manufacture technology, printing settings, and postprocessing procedures plays an essential role in the accuracy of additively manufactured casts. Clinical studies are required to confirm these findings. We don’t have clinical studies to confirm this finding, its based on virtual studies Hian Parize, J Prosthet Dent, 2022 CAD/CAM materials § Metal: base metal ,noble and high noble § Composite § All ceramic: lithium disilicate (LiSi, e.max CAD) The only way of doing zirconia is through CAD/CAM § Zirconia: Katana, Bruxier, ZirCAD Lithium disilicate can be pressed can be printed so it has multiple ways unlike zirconia. § Resin Also used for printed models § Polymethylmethacrylate These are used for provisionals, if you want long term provisional then we use PMMA § CAD/CAM materials § Metal Accuracy of CAD-CAM milling versus conventional lost-wax casting for single metal copings: A systematic review and meta-analysis o When CAD-CAM milling was used to fabricate single metal copings, no advantage in precision was found compared with lost-wax casting o Single metal copings cast from handmade conventional wax patterns had better marginal adaptation than those fabricated via CAD-CAM milling o Noble metal copings had improved marginal accuracy than base metal copings for both the casting and milling methods. So for metals we still believe that the conventional way provides us with better marginal accuracy but again this was found in literature and they are improving it Jun Yang, J Prosthet Dent, 2022 § CAD/CAM materials § Composite § Ultrathin CAD-CAM glass-ceramic and composite resin occlusal veneers for the treatment of severe dental erosion: An up to 3-year randomized clinical trial In this study they did a comparison between theses groups: o E.max (all ceramic) group vs Lava ultimate (composite) group Ceramic is stronger than composite o Results: Its a short term randomized trial so we don’t know on the long term which Ø No restorations were lost group will overvome Ø Five partial failures, in the form of chipping (all scored 4), were observed in the composite resin group (Lava Ultimate) Ø The Kaplan-Meier survival rates were 100% for ceramic and 84.7% (SE 0.065%) for composite resin. Differences between the 2 groups were not statistically significant (P=.124). Luis Schilichting, Randomized controlled trial, 2022 Keep this chart in your mind Opaque and strong translucent, aesthetic, weaker Hybrid its a combination not a resin and not a ceramic The difference in these 2 subgroups is the amount of resin sometimes resin work as the matrix of the material and sometimes its only added as few particles in the material After they are milled they look bigger then put in the oven then they undergo shrinkage and look smaller  in the oven The purple one the unfired ceramic after firing it turns into white then you polish it, stain it then glaze it Full crowns, copings, framework for partial dentures unfortunally not everything can be done digitally So in highly aesthetic areas where we have high aesthetic demands like anteriors we still do manual layering in conventional way because it provides more room for aesthetics like the layering with different shades of ceramics and producing some type of translucency and mandolin (?) effect. the digital workflow is kind of limiting with the aesthetic outcomes posteriors don’t matter as much as anteriors In anteriors even if we do it digitally we still cut back from facial surface and add manual powder and liquid porcelain to complete the full contour of the crown Zirconia has a zirconia polishing Kit Emax has a polishing kit for emax Each manufacturer has a polishing kit for their own ceramics after polishing we can apply some stains to mimic natural teeth and then a glaze layer to make the crown shiny  Staining Here we apply yellow stains in the interproximal area to mimic the original teeth Any stain or glaze material you apply you have to fire it in the oven after that so it crystallizes  In the last five minutes of the lecture the doctor went through a case of one of her patients if you are interested go back to the lecture at 24:12 and watch it § Skorulska A, Piszko P, Rybak Z, Szymonowicz M, Dobrzyński M. Review on polymer, ceramic and composite materials for cad/cam indirect restorations in dentistry— Application, mechanical characteristics and comparison. Materials. 2021 Mar 24;14(7):1592. § Schlichting LH, Resende TH, Reis KR, Dos Santos AR, Correa IC, Magne P. Ultrathin CAD-CAM glass-ceramic and composite resin occlusal veneers for the treatment of severe dental erosion: An up to 3-year randomized clinical trial. The Journal of Prosthetic Dentistry. 2022 Aug 1;128(2):158-e1. § Park BS, Lee WY, Ra YJ, Lee HK, Gu BM, Yang JT. Surgical outcomes for native valve endocarditis. The Korean journal of thoracic and cardiovascular surgery. 2020 Feb;53(1):1. § Siqueira R, Galli M, Chen Z, Mendonça G, Meirelles L, Wang HL, Chan HL. Intraoral scanning reduces procedure time and improves patient comfort in fixed prosthodontics and implant dentistry: A systematic review. Clinical oral investigations. 2021 Dec;25(12):6517-31.