Final - CAD_CAM_Implant-assisted RPD_YKK.txt

CAD/CAM removable partial dentures (RPDs) and new materials & implant-retained RPDs Prof. Young K. Kim, DMD, DMSc, FACP Diplomate & Fellow, American Board of Prosthodontics Clinical Assistant Professor, NYUCD, Dept. of Prosthodontics Editor & Co-leader, NYU Implant Restorative Protocol ’...

CAD/CAM removable partial dentures (RPDs) and new materials & implant-retained RPDs Prof. Young K. Kim, DMD, DMSc, FACP Diplomate & Fellow, American Board of Prosthodontics Clinical Assistant Professor, NYUCD, Dept. of Prosthodontics Editor & Co-leader, NYU Implant Restorative Protocol ’20 Editor & Co-leader, NYU Robotics Surgical Protocol ’21 / ’22 NEW YORK UNIVERSITY COLLEGE OF DENTISTRY Waves of innovation Photo by Ryan Craig Waves of innovation in DENTISTRY Evidence-based dentistry Foundational consensus Experimental research Waves of innovation in RPD New Materials CAD/CAM Implant-retained Objectives Identify CAD/CAM removable partial dentures and discuss basic information Explore the digital workflow of framework fabrication Describe the pros/cons of digital CAD/CAM RPDs (compared to conventional) Examine new materials for removable partial denture Introduce the concept of implant-retained removable partial denture CAD/CAM RPDs Basic information Source - Marotta Dental Studios • CAD (computer-aided design) • CAM (computer-aided manufacture) • Either additive (rapid prototyping or RP) or subtractive manufacturing (milling; computer numerical control or CNC) • RP = solid freeform fabrication or layered manufacturing (Lima JM, 2014) • Milling accuracy = within 10 um (Abduo J, 2014) • Currently available on both fixed and removable restorations (Kanazawa M, 2011) CAD/CAM RPDs Digital design principles “…CAD/CAM and digital dentistry will only affect the means of fabrication or adjudicate the treatment planning process. The design concepts promoted by Prof. Kratochvil will continue to endure.” Prof. John Beumer CAD/CAM RPDs Conventional design principles Dr. Young K. Kim, DMD, DMSc, FACP Conventional lost/wax CAD/CAM RPDs Conventional design principles Digital design principles Same rules apply! Dr. Young K. Kim, DMD, DMSc, FACP Conventional lost/wax CAD/CAM RPDs Digital workflow of framework fabrication Impression • Obtaining a digital model (either intra-oral digital scanning or laboratory digital scan of a stone cast) CAD/CAM RPDs Digital workflow of framework fabrication Impression CAD • Digital designing (either milling or 3D printed) using modeling CAD softwares (3Shape Dental System and Exocad) • Path of insertion • Undercuts • Virtual block-outs • Digital designing (either milling or 3D printed) using modeling CAD softwares (3Shape Dental System and Exocad) (Ye H, 2017) CAD/CAM RPDs Digital workflow of framework fabrication Impression CAD SLA file • Exporting the designed RPD framework in the form of a stereolithography (SLA) file • Can be used for the additive or subtractive manufacturing of RPD framework (Ye H, 2017) CAD/CAM RPDs Digital workflow of framework fabrication Impression CAD SLA file • Definitive prosthesis directly from • The digital design OR • From an intermediate product (resin-elimination pattern) which will be invested and cast CAM CAD/CAM RPDs Digital workflow of framework fabrication Impression CAD SLA file Milling (CNC) Spark erosion Stereolithography (SLA) Digital light projection (DLP) Jet (PolyJet/ProJet) printing Diamond grinding Carbide milling Subtractive Laser milling Additive CAM Direct/Selective laser melting (SLM) (Bilgin M, 2016) New Materials in RPDs Conventional metal framework • Cobalt-chromium (vitallium) or nickel-chromium (ticonium) • Advantages (Campbell SD, 2017) • Economical, high strength and stiffness, heat conductivity, resilience, and biocompatibility • Disadvantages (Zoidis P, 2016) • Display of metal clasps (aesthetic concern), heavier weight, metallic taste, and allergic reactions New Materials in RPDs Alternative materials (thermoplastic resins) Tri-Mack Plastics Mfg. Corp New Materials in RPDs Alternative materials (thermoplastic resins) • Thermoplastic resins with great potential in CAD/ CAM industry • Need further comprehensive physical evaluation for their clinical application • Current challenges = color stability, difficult repairing, fracture, surface deformation, insufficient rigidity and support • Disadvantages = challenging relining, poor adherence, conventional metal rests vs. nontransitional thermoplastic resin (Fueki K, 2014) New Materials in RPDs PEEK (Poly-Ether-Ether-Ketone) PAEK (Poly-Aryl-Ether-Ketone) PEKK (Poly-Ether-Ketone-Ketone) Source: Arkema/Machina Corp New Materials in RPDs PEEK vs. PAEK vs. PEKK Mechanical properties = roughly the same ! Source : TenCate New Materials in RPDs PEEK vs. PAEK vs. PEKK Lower melting temperature = speeds up in-situ consolidation ! Source : TenCate New Materials in RPDs Aryl ketone polymer (AKP) • High-performance medical grade • PAEK-based • High biocompatibility, superior mechanical properties, high temperature resistance, chemical resistance, excellent rigidity • Following the conventional RPD design concepts • Stainable (better aesthetics) • Lighter weight (1/3 of Cr-Co) • Excellent precision & accuracy • Further studies necessary Source - Marotta Dental Studios (Zoidis P, 2016) New Materials in RPDs Aryl ketone polymer (AKP) • Necessitates more thicker and bulkier clasps • May affect Pt’s speech • Doesn’t conduct heat as much • Influencing heat perception → Taste can be affected Source - Marotta Dental Studios (Zoidis P, 2016) Implant-retained RPDs Rationale McCracken’s Removable Partial Prosthodontics (2016) Implant-retained RPDs Rationale STRATEGIC PLACEMENT IMPROVING COMFORT & OCCLUSAL FUNCTION SUPPORT RETENTION McCracken’s Removable Partial Prosthodontics (2016) Implant-retained RPDs Rationale Implant-retained RPD • To improve denture design by optimizing the distribution of abutments • Non-rigid connector system between teeth and implants • Preventing complications (i.e. intrusion of teeth or progressive bone loss) (Krennmair G, 2007) Implant-retained RPDs Advantages Implant-retained RPD vs RPD • Increased retention, stability, and improvement in patient satisfaction (Mifiritsky E, 2004) • Turning Kennedy Class I or II (distal extention) into III (more favorable) (Turkyilmaz I., 2009) • Might prevent from Combination Syndrome manifestations (Mijiritsky E, 2007) • Improving Pt’s chewing ability (i.e. greater bite force + area of contact points) (Ohkubo C, 2008) • Bone preservation (Senna PM, 2011) Implant-retained RPDs Disadvantages Implant-retained RPD vs RPD • Increased cost • Surgical interventions • More complicated clinical & laboratory process Implant-retained RPDs Attachment options: 1) healing caps Implant-retained RPDs Attachment options: 1i) precision attachment (era) Implant-retained RPDs Attachment options: 1ii) precision attachment (bar/locator) Photo Courtesy of Dr. Ted Tso, DMD, MMSc, FACP Implant-retained RPDs Attachment options: 1v) abutments for a fixed prosthesis Photo Courtesy of Dr. Hyu Im, DDS, MSD, CAGS Implant-retained RPDs Attachment options: v) telescopic crowns Waves of innovation in RPD Evidence-based dentistry 2022 Foundational consensus Experimental research Foundation is critical NYUCD Foundational consensus Experimental research Thank you Instagram Youtube Linkedin YKK Website [email protected] @ykk_pros YK im Prosthodontist